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1
Park, ShinJu. "Water vapor estimation using near-surface radar refractivity during IHOP_2002." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81424.
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A ground-based radar refractivity mapping technique is used to measure water vapor near the surface during the International H2O Project in May and June, 2002 (IHOP_2002). Radar-measured refractivity is compared with refractivity estimated from surface station observations during this field experiment. Bias in radar and station refractivity is found to occur often when humidity is high. Possible reasons for this difference between radar and station observations are discussed. Most of the biases were associated either with inaccurate humidity observations by stations or with the small height difference of the two measurements. With confirming this last observation further during these wet ground conditions, radar refractivity shows much better agreement with radiosonde sounding refractivity just above the surface than with station refractivity.In addition, columnar water vapor is computed using the mixing ratios retrieved from radar and station refractivity and using the observed height of the convective boundary layer from a FM-CW radar. Surface moisture fluxes are computed as a residual of the columnar water vapor and compared with observations from flux-towers, which compute this using the eddy-covariance technique. Although the results show that the radar-based measurements may have some skill over longer time periods, the technique completely fails to reproduce observations over scales smaller than 1 hour.
2
Koby, Timothy Robert. "Development of a Trajectory Model for the Analysis of Stratospheric Water Vapor." Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493564.
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To study stratospheric water vapor, a new trajectory model was created. The model is built from first principles specific to stratospheric motion and can run on any gridded dataset, making it more versatile than current solutions. The design of a new model was motivated by measurements of elevated stratospheric water vapor, which in situ isotopic measurements have determined to be tropospheric in origin. A moist stratosphere has substantial feedbacks in the climate system including radiative, chemical, and biological effects. Additionally, elevated stratospheric water vapor is theorized as an important coupling in the historical transition to the Eocene, 56 million years ago, as well as emergence from the Eocene 40 million years ago. This transition mirrors modern climate change, both in surface temperature and carbon dioxide increase. However, the historical transition became much more extreme and settled to a state of warm temperatures from the equator to the poles with little variation in between. The lack of latitudinal gradient in temperature is associated with a moist stratosphere, which provides additional motivation for thoroughly understanding the effects of adding water vapor to the stratosphere in a climatological context.
The time evolution of water vapor enhancements from convective injection is analyzed by initializing trajectories over satellite-measured water vapor enhancements. The model runs show water vapor concentrations that remain elevated over the background concentrations for several days and often over a week, which is of the timescale that warrants concern over increased halogen catalyzed ozone loss and the subsequent risk to public health. By analyzing stratospheric winds during the summer months over North America using normalized angular momentum, a pattern of frequent stratospheric anticyclonic activity over North America emerges as a unique feature of the region. This provides a mechanism for the modeled persistent elevated water vapor and validates observations. In a climate like today's with increasing surface radiative forcing, the magnitude and frequency of convective injection may increase, with dramatic consequences on the climate system and human health.Physics
3
Vann, Lelia Belle. "Ultra narrow band fiber optic Bragg grating filters for atmospheric water vapor measurements." Diss., The University of Arizona, 2003. http://hdl.handle.net/10150/280456.
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Optical fibers have revolutionized telecommunications. Much of the success of optical fiber lies in its near-ideal properties: low transmission loss, high optical damage threshold, and low optical nonlinearity. The photosensitivity of an optical fiber was accidentally discovered by Hill, et al. in 1978. However, the technological advances made in the field of photosensitive optical fibers are relatively recent. This fascinating technology of photosensitive fiber is based on the principle of a simple in-line all-fiber optical filter. It has been shown that the transmission spectrum of a fiber Bragg grating can be tailored by incorporating multiple phase-shift regions during the fabrication process. Phase shifts open up ultra narrowband transmission windows inside the stop band of the Bragg grating. As a specific application, this research is focused on applying this technology in future space-based water vapor DIfferential Absorption LIDAR (DIAL) systems to improve the performance of space-based LIDAR systems by rejecting the reflected solar background. The primary goal of this research effort was to demonstrate the feasibility of using ultra narrow band fiber optic Bragg grating filters for atmospheric water vapor measurements. Fiber Bragg gratings were fabricated such that two transmission filter peaks occurred and were tunable, one peak at a 946 nm water vapor absorption line and another peak at a region of no absorption. Both transmission peaks were in the middle of a 2.66-nm stop band. Experimental demonstration of both pressure and temperature tuning was achieved and characterization of the performance of several custom-made optical fiber Bragg grating filters was made. To our knowledge these are the first optical fiber gratings made in this frequency range and for this application. The bandwidth and efficiency of these filters were measured and then these measurements were compared with theoretical calculations using a piecewise matrix form of the coupled-mode equation. Finally, an ultra narrow band water vapor DIAL filter was characterized having two pass bands less than 8 pm and peak transmissions greater than 80 percent. Such fiber optic filters are now ready for integrating into space-based water vapor LIDAR systems. More broadly, these filters have the characteristics that will revolutionized satellite remote-sensing.
4
Wassenberg, Chris Alan 1959. "Development of a multi-frequency microwave radiometer for the measurement of atmospheric water vapor and temperature profiles." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277271.
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The development of a system capable of continuously monitoring atmospheric brightness temperatures at H₂O and O₂ absorption/emission windows is discussed. Designed for remote (unattended) operation, the system employs radiometric technology and operates at microwave frequencies, thereby achieving essentially all-weather operation. The design, construction and calibration of the radiometer system are described. In addition, some of the physics and mathematics on which the theory of atmospheric radiative transfer is based is presented. Examples of measurements made during the system's first operational performance study is presented along with preliminary calibration calculations. Future work required to refine the measurement and calibration techniques is discussed.
5
Wang, Sheng-Hung. "Large-scale moisture flux analysis for the United States." Columbus, Ohio : Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1073015878.
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Thesis (Ph. D.)--Ohio State University, 2004.Title from first page of PDF file. Document formatted into pages; contains xviii, 154 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Jeffery C. Rogers, Dept. of Atmospheric Science. Includes bibliographical references (p. 142-153).
6
Pan, Xiong. "Theoretical Studies of Atmospheric Water Complexes." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/1163.
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Intermolecular complexes between H₂O and atmospheric species HO, HO₂, H₂O₂, O₃, NO and NO₂ have been studied by ab initio molecular orbital methods. The studies have been performed to the MP2 theory level by using 4-31G, 6-31G, D95, 6-31G**, D95**, 6-311G**, 6-311+G**, 6-311++G**, 6-311+G(2d,lp) and 6-311+G(2d,2p) basis sets. The geometries were fully optimized. The vibrational frequencies were calculated. The Basis Set Superposition Error (BSSE) were estimated. Finally, the binding energies of the complexes were predicted with other thermochemical properties. The binding energies of H₂O•HO, H₂O•HO₂, H₂O•H₂O₂, H₂O•O₃, H₂O•NO and H₂O•NO₂ are estimated to be 5.7±0.6, 8.9±1.0, 7.3±1.3, 1.8±0.2, 1.17 (no BSSE correction) and 2.98 (no BSSE correction) Kcal/Mol, respectively. The Kcq for dimerization to yield H₂O•HO, H₂O•HF, H₂O•HO₂, H₂O•H₂O and H₂O•H₂O₂ are estimated to be 0.11, 2.8, 3.3, 0.067 and 0.11 atm¯¹, respectively. The H₂O•HO, H₂O•HF, H₂O•HO₂, H₂O•H₂O and H₂O•H₂O₂ are quite strongly bonded complexes, while H₂O•O₃, H₂O•NO and H₂O•NO₂ are only weakly bonded complexes. The Kcq changes with temperature are discussed, and their importance in atmospheric chemistry are addressed.
7
Sargent, Maryann Racine. "The Response of Stratospheric Water Vapor to a Changing Climate: Insights from In Situ Water Vapor Measurements." Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10623.
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Stratospheric water vapor plays an important role in the Earth system, both through its role in stratospheric ozone destruction and as a greenhouse gas contributing to radiative forcing of the climate. Highly accurate water vapor measurements are critical to understanding how stratospheric water vapor concentrations will respond to a changing climate. However, the past disagreement among water vapor instruments on the order of 1 – 2 ppmv hinders understanding of the mechanisms which control stratospheric humidity, and the reliable detection of water vapor trends. In response to these issues, we present a new dual axis water vapor instrument that combines the heritage Harvard Lyman-\(\alpha\) hygrometer with the newly developed Harvard Herriott Hygrometer (HHH). The Lyman-\(\alpha\) instrument utilizes ultraviolet photo-fragment fluorescence detection, and its accuracy has been demonstrated though rigorous laboratory calibrations and in situ diagnostic procedures. HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell; it demonstrated in-flight precision of 0.1 ppmv (1-sec) with accuracy of 5%±0.5 ppmv. We describe these two measurement techniques in detail along with our methodology for calibration and details of the measurement uncertainties. We also examine the recent flight comparison of the two instruments with several other in situ hygrometers during the 2011 MACPEX campaign, in which five independent instruments agreed to within 0.7 ppmv, a significant improvement over past comparisons. Water vapor measurements in combination with simultaneous in situ measurements of \(O_3\), CO, \(CO_2\), HDO, and HCl are also used to investigate transport in the Tropical Tropopause Layer (TTL). Data from the winter 2006 CR-AVE campaign and the summer 2007 TC4 campaign are analyzed in a one-dimensional mixing model to explore the seasonal importance of transport within the TTL via slow upward ascent, convective injection, and isentropic transport from the midlatitude stratosphere. The model shows transport from midlatitudes to be significant in summer and winter, affecting ozone concentrations and therefore the radiative balance of the TTL. It also shows significant convective influence up to 420 K potential temperature in both seasons, which appreciably increases the amount of water vapor above the tropopause.Engineering and Applied Sciences
8
Wiedner, Martina Corinna. "Atmospheric water vapour and astronomical millimetre interferometry." Thesis, University of Cambridge, 1998. http://www.mma.nrao.edu/workinggroups/cal%5Fimaging/183GHz.html.
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Hancock, Jay Brian 1976. "Passive microwave and hyperspectral infrared retrievals of atmospheric water vapor profiles." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8573.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 231-234).
Two clear-air relative humidity profile estimators were designed and implemented using neural networks. The microwave estimator is the first to utilize 54-, 118-, and 183-GHz channels for simultaneously retrieving a relative humidity profile. It utilizes 2 separate instruments simultaneously. The first instrument is a medium-resolution dual-band radiometer with one set of 8 double-sideband 118-GHz channels and a second set of 8 single-sideband 54-GHz channels. The other instrument is a high-resolution double-sideband radiometer with a set of 3 183-GHz channels, and additional channels at 89, 220, and 150 GHz. The infrared estimator is among the first to utilize a hyperspectral infrared aircraft instrument for relative humidity profile retrievals. The infrared instrument is a 9000-channel interferometer operative over the wavelength range of 3.8-16.2 microns. Both estimators utilized neural networks of comparable topology and training methods. The training data was generated from the SATIGR set of 1761 RAOBs using a different implementation of the discrete radiative transfer equation for each estimator. The test data were from two clear-air ER-2 aircraft flights during the tropical CAMEX-3 mission near Andros Island. The retrievals were robust in the face of unknown instrument bias and noise, which introduced a difference between the training data and the flight data. A noise-averaging technique achieved robustness in exchange for a degradation in sensitivity of the retrieval algorithms. Robustness was demonstrated by the retrieval agreement between the microwave and infrared instruments. The theoretical average rms error in relative humidity for the various techniques on the training set was 12% for the microwave estimator, 11% for the infrared, and 10% for a linear regression of the two. In application to two flights, the rms error was 9.4% for the microwave, 7.7% for the infrared, and 7.7% for the combination, based on comparisons with nearby radiosondes.
by Jay Brian Hancock.
S.M.
10
Querel, Richard Robert, and University of Lethbridge Faculty of Arts and Science. "Remote sensing of atmospheric water vapour above the Chilean Andes." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Physics and Astronomy, 2010, 2010. http://hdl.handle.net/10133/2586.
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Water vapour is the principle source of opacity at infrared wavelengths in the Earth’s atmosphere.
In support of site testing for the European Extremely Large Telescope (E-ELT),
we have used La Silla and Paranal as calibration sites to verify satellite measurements of
precipitable water vapour (PWV). We reconstructed the PWV history over both sites by
analysing thousands of archived high-resolution echelle calibration spectra and compared
that to satellite estimates for the same period. Three PWV measurement campaigns were
conducted over both sites using several independent measurement techniques. Radiosondes
were launched to coincide with satellite measurements and provide a PWV reference
standard allowing intercomparison between the various instruments and methods. This
multi-faceted approach has resulted in a unique data set. Integral to this analysis is the
internal consistency provided by using a common atmospheric model.xvii, 206 leaves : ill. (some col.) ; 28 cm
11
Beucler, Tom(Tom George). "Interaction between water vapor, radiation and convection in the tropics." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121758.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 227-251).
The spatiotemporal variability of water vapor near the Equator remains poorly understood because convective organization simultaneously spans the cloud scale (~ 10km) and the planetary scale (~ 10, 000km). Spatiotemporal variability of tropical water vapor may result from internal instabilities of the atmosphere, arising from the interaction between water vapor, radiation and convection. The present work leverages the instability of radiative-convective equilibrium, the most fundamental state of the tropical atmosphere, to connect convective organization in cloud-permitting models with the observed variability of water vapor through common physical mechanisms. First, we propose a simple theory that explains when instability of radiative-convective equilibrium may occur: If the total atmospheric cooling decreases with column water vapor, then radiative-convective equilibrium may be unstable to the growth of moist and dry perturbations.
Secondly, we combine a linear response framework with the weak temperature gradient approximation to analyze the interaction between convection, radiation and water vapor at each level of the atmosphere. We find that convection may interact with radiation to trigger the growth of mid-tropospheric water vapor anomalies by transporting water vapor to the upper troposphere, where it can prevent lower-tropospheric water vapor from radiatively cooling to space. Thirdly, we turn to the spatial organization of water vapor anomalies and relate the evolution of the size of moist and dry regions to diabatic fluxes in twenty cloud-permitting simulations on large domains. Longwave radiation from ice clouds aggregates convection at larger scales, shortwave radiation aggregates convection at smaller scales, and surface enthalpy fluxes smooth out water vapor anomalies through their enthalpy disequilibrium component.
Finally, we relate the transient zonal variability of precipitable water to convective-aggregation mechanisms in realistic models and observations of the atmosphere. Radiative fluxes generate transient water vapor structures of planetary scales, while surface enthalpy fluxes and horizontal energy transport act to smooth out these structures, suggesting parallels between observations and idealized simulations of aggregated convection.
by Tom Beucler.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences
12
Nessel, James Aaron. "Estimation of Atmospheric Phase Scintillation Via Decorrelation of Water Vapor Radiometer Signals." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1447701180.
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Larson, Kristin Ann. "Tropical climate sensitivities : clouds, water vapor, radiation and large-scale circulation /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/10015.
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Rizk, Bashar. "Observations and modelling of the Martian water vapor budget for 1988-1989." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185634.
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During 1988-89, the 1.5 m telescope on Mt. Bigelow, Arizona, combined with the Lunar and Planetary Laboratory echelle spectrograph, recorded 20 spectral CCD images of Mars during early spring, mid- and late summer, and autumnal equinox in its southern hemisphere. These images contained absorption features which permitted latitudinally resolved measurements of water vapor column abundance in the martian atmosphere on these four occasions, corresponding to the areocentric longitudes (L(s)) 208, 320, 340, and 360°. This dissertation describes the acquisition, analysis, and modeling of this data set. Photochemical models at different latitudes predicted ozone column abundance at L(s) = 208° when initialized by the observed water vapor abundances. Matching simultaneous ozone abundances, also measured from the ground, required eddy diffusivities at altitudes between 5 and 15 km that were at least two orders of magnitude lower than the values greater than 10⁸ cm² sec⁻¹ assumed above 30 km altitude, especially at south polar latitudes. Legendre polynomials and interpolating parabolas described the observed spatial and temporal behavior of the martian water vapor for L(s) = 320, 340, and 360°. Integrating the fits with latitude derived visible disk and globally averaged abundances as a function of time. A budget based on these abundances suggested the southern hemisphere subsurface to be a source, and therefore a reservoir, of water vapor during this season. The large magnitudes and signs of effective meridional diffusivities for the data implied the water vapor's disappearance to be more likely due to condensation and adsorption into local sinks than to atmospheric transport. When compared with Viking water vapor data, the Catalina abundances hinted that dust was a mechanism for shielding water vapor from ground-based observation and that northward transport was more efficient during a dusty southern spring and summer than during a dustless one. Finally, a one-dimensional analytical meridional diffusive model and a two-dimensional diabatic circulation water transport model confirmed the idea of a southern hemisphere surface source and sink for the Catalina water vapor, and more efficient northward water transport during dusty southern spring and summer. Moreover, both transport models suggested that the large amount of water seen from the ground during 1969 was not sublimed from a south polar residual cap of water ice.
15
Pazera, Marcin. "Development of experimental methods for characterizing water vapor transmission in building materials." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2007. http://wwwlib.umi.com/cr/syr/main.
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Smith, Jessica Birte. "The Sources and Significance of Stratospheric Water Vapor: Mechanistic Studies from Equator to Pole." Thesis, Harvard University, 2011. http://dissertations.umi.com/gsas.harvard:10034.
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It is the future of the stratospheric ozone layer, which protects life at Earth’s surface from harmful ultraviolet (UV) radiation, that is the focus of the present work. Fundamental changes in the composition and structure of the stratosphere in response to anthropogenic climate forcing may lead to catastrophic ozone loss under current, and even reduced, stratospheric halogen loading. In particular, the evolution toward a colder, wetter stratosphere, threatens to enhance the heterogeneous conversion of inorganic halogen from its reservoir species to its catalytically active forms, and thus promote in situ ozone loss. Water vapor concentrations control the availability of reactive surface area, which facilitates heterogeneous chemistry. Furthermore, the rates of the key heterogeneous processes are tightly controlled by the ambient humidity. Thus, credible predictions of UV dosage require a quantitative understanding of both the sensitivity of these chemical mechanisms to water vapor concentrations, and an elucidation of the processes controlling stratospheric water vapor concentrations. Toward this end, we present a set of four case studies utilizing high resolution in situ data acquired aboard NASA aircraft during upper atmospheric research missions over the past two decades. 1) We examine the broad scale humidity structure of the upper troposphere and lower stratosphere from the midlatitudes to the tropics, focusing on cirrus formation and dehydration at the cold-point tropical tropopause. The data show evidence for frequent supersaturation in clear air, and sustained supersaturation in the presence of cirrus. These results challenge the strict thermal control of the tropical tropopause. 2) We investigate the likelihood of cirrus-initiated activation of chlorine in the midlatitude lower stratosphere. At midlatitudes the transition from conditions near saturation below the local tropopause to undersaturated air above greatly reduces the probability of heterogeneous activation and in situ ozone loss in this region. 3) We probe the details of heterogeneous processing in the wintertime Arctic vortex, and find that in situ measurements of OH provide incontrovertible evidence for the heterogeneous reaction of HOCl with HCl. This reaction is critical to sustaining catalytically active chlorine and prolonging ozone loss in the springtime vortex. 4) We revisit the topic of midlatitude ozone loss with an emphasis upon the response of ozone in this region to changes in the chemical composition and thermal structure of the lower stratosphere induced by anthropogenic climate change. Specifically, we show evidence for episodic moisture plumes in the overworld stratosphere generated by the rapid evaporation of ice injected into this region by deep convection, and find that these high water vapor plumes have the potential to alter the humidity of the lower stratosphere, and drastically increase the rate of heterogeneous chemistry and in situ ozone loss, given sufficient reactive surface.Earth and Planetary Sciences
17
Williams, Joshua Bruce. "Algorithm Development for Column Water Vapor Retrieval Using the SAM Sensor." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/59.
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To understand and model the energetics of the Sun-Earth connection, measurements of specific atmospheric molecules are beneficial. The objective is to formulate an algorithm to derive temporally varying atmospheric water vapor concentrations as functions of altitude, latitude, and longitude from solar irradiance absorption measurements. The Visidyne SAM (Sun and Aureole Measurement) instrument, which studies the size and distribution of cloud particles, was used to obtain the experimental data. By introducing a spectrometer to the SAM instrument, column water vapor is produced as part of the data product. A new model optimized algorithm is developed and tested versus existing algorithms. Through a least-squares analysis, the new algorithm showed an improvement of a factor of 23 over the industry standard. A test was also conducted to determine which water absorption bandpass produces the smallest error. Through these tests a model optimized algorithm has been produced.
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Jian, Yongxiao. "Retrieval of temperature and water vapor from combined satellite and ground based ultra-spectral measurements." Thesis, Hampton University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3592878.
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Ultra-spectrometers with a spectral resolution better than 1 cm-1, such as AIRS on the AQUA, IASI on the Metop-A/B, and CrIS on the Suomi-NPP, have become operational during the past decade. The radiance spectra measured by these satellite-borne spectrometers provide soundings of the atmosphere with relatively high vertical resolution and high accuracy except for the lower atmosphere. Meanwhile, many ground-based ultra-spectrometers based on the Michelson Interferometer have been incorporated into the Department of Energy Atmospheric Radiation Measurement facilities and aboard NOAA research vessels. These instruments provide temperature and water vapor soundings within the planetary boundary layer continuously with very high vertical resolution. This dissertation develops a retrieval procedure which can combine the radiance measured by ground-based spectrometers and coincident observation from satellite-borne instruments to improve retrieval results throughout the lower atmosphere.
To verify the feasibility and improved accuracy of the combined retrieval, 90 clear sky cases from four in-situ radiosonde measurement locations or geographical regions, were selected for this study. Each region consists of radiosonde measurements of temperature and water vapor, downwelling radiance spectra measured at approximately the balloon launch time, and upwelling radiance observation by IASI at the location and time coincident with the surface radiance and radiosonde measurements.
These cases indicate, that when compared with the retrieval from upwelling radiance or downwelling radiance spectra only, there is a significant improvement of the retrieval using combined upwelling and downwelling radiance spectra is observed. At altitude below the 800 hPa pressure level, the errors using the combined retrieval are about 0.5 – 1 K in temperature, and 20 – 40 % for water vapor mixing ratio. These errors are approximately one-third the magnitude of errors for the sounding retrieval obtained using satellite upwelling radiance alone.
19
Lathem, Terry Lee. "On the water uptake of atmospheric aerosol particles." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/50112.
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The feedbacks among aerosols, clouds, and radiation are important components for understanding Earth's climate system and quantifying human-induced climate change, yet the magnitude of these feedbacks remain highly uncertain. Since every cloud droplet in the atmosphere begins with water condensing on a pre-existing aerosol particle, characterizing the ability of aerosols to uptake water vapor and form cloud condensation nuclei (CCN) are key to understanding the microphysics behind cloud formation, as well as assess the impact aerosols have on the Earth system. Through a combination of controlled laboratory experiments and field measurements, this thesis characterizes the ability of atmospheric aerosols to uptake water vapor and become CCN at controlled levels of water vapor supersaturation. The origin of the particle water uptake, termed hygroscopicity, is also explored, being from either the presence of deliquescent soluble material and/or adsorption onto insoluble surfaces. The data collected and presented is comprehensive and includes (1) ground samples of volcanic ash, collected from six recent eruptions re-suspended in the laboratory for analysis, (2) laboratory chamber and flow-tube studies on the oxidation and uptake of surface active organic compounds, and (3) in-situ aircraft measurements of aerosols from the Arctic background, Canadian boreal forests, fresh and aged biomass burning, anthropogenic industrial pollution, and from within tropical cyclones in the Atlantic basin. Having a more thorough understanding of aerosol water uptake will enable more accurate representation of cloud droplet number concentrations in global models, which can have important implications on reducing the uncertainty of aerosol-cloud-climate interactions, as well as additional uncertainties in aerosol transport, atmospheric lifetime, and impact on storm dynamics.
20
Conant, William Christopher. "Interactions between aerosol, water vapor, and solar radiation /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p3025938.
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Hausmann, Petra [Verfasser], and Ralf [Akademischer Betreuer] Sussmann. "Long-Term Monitoring of Atmospheric Water Vapor and Methane / Petra Hausmann ; Betreuer: Ralf Sussmann." Augsburg : Universität Augsburg, 2017. http://d-nb.info/1143518926/34.
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Brooks, Christopher K. "Multispectral analysis of maritime clouds at night in the presence of atmospheric water vapor." Thesis, Monterey, Calif. : Naval Postgraduate School, 1992. http://handle.dtic.mil/100.2/ADA256699.
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Thesis (M.S. in Meteorology)--Naval Postgraduate School, June 1992.Thesis Advisors: Durkee, Philip A. ; Wash, Carlyle H. "June 1992." Description based on title screen as viewed on March 10, 2009. Includes bibliographical references (p. 71-72). Also available in print.
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Brösamlen, Gerd. "Radiative transfer in lognormal multifractal clouds and analysis of cloud liquid water data." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68158.
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The study of radiative transfer in multifractal clouds is of great interest, an important application being to Global Climate Models. In this work we develop a formalism analogous to the multifractal singularity formalism for understanding photon scattering statistics in radiative transfer in multifractals, and test the results numerically on lognormal multifractals. Although the results are only exactly valid in the thick cloud limit, the approximation is found to be quite accurate down to optical thickness of $ tau approx1$-10, so the results may be widely applicable. Furthermore we show the possibility of "renormalizing" the multifractal by replacing it with a near equivalent homogeneous medium but with a "renormalized" optical thickness $ tau sp{1/(1+C sb1)}$ where C$ sb1$ is the codimension of the mean singularity of the cloud. We argue that this approximation is likely to continue to be valid for multiple scattering, and is also compatible with recent results for diffusion on multifractals. Finally we analyze cloud liquid water content data and estimate the universal multifractal indices. We find that the scaling is respected over the whole range 5m-330km and that the cloud can in fact be reasonably described by a lognormal multifractal.
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Meunier, Véronique. "On the performance of ground-based microwave radiometers in tomographic measurements of a 2D atmospheric water vapor field." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121178.
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Since water vapor plays an important role in the atmosphere, many different instruments capable of measuring quantities of vapor are available to atmospheric scientists. One such instrument is the microwave radiometer that can measure low-resolution profiles of water vapor. However, in the case of boundary layer and convective initiation studies, the resolution requirements by the scientific community are more demanding than what the instrumentation is currently capable of providing. Therefore, measurements techniques have been developed to help bridge this gap. One of these measurement techniques is tomography. The goal of this technique is to combine several similar instruments providing measurements at low ranging resolution or of integrated values, in such a way that they provide information on crossing paths, thereby making it possible to provide measurements at higher resolution. This technique has been used in meteorology to measure fields of water vapor and clouds. In this study, we examined the performance of the tomographic retrieval of a 2D water vapor field using ground-based microwave radiometry. Since microwave tomography requires the radiometers to scan near the horizon in order to provide measurements of water vapor near the surface, we first examined the biases that occur when scanning at these low elevations. The biases may be caused by the antenna beam width, the channel bandwidth, and the propagation models used in the instrument model. It was found that the errors in antenna beam width are larger that those of channel bandwidth. Then, we evaluated the information content and the accuracy of the microwave radiometer tomographic retrieval. The impact of different instrument characteristics (number of frequencies and elevation angles) and of different instrument set-ups (number and spacing between instrument) on the retrieval's solution was assessed. Although the use of multiple instruments in a tomographic set-up did improve the information content of the retrieval, the accuracy of the field was limited by the passive nature of the radiometric measurement, especially in the case of very variable water vapor fields. Finally, we investigated the impact of adding a Raman lidar to the microwave tomographic retrieval. This was done with the hope that including an active remote sensor would help the retrieval in variable fields. Three different ways to include the Raman lidar were tried. The simplest, and best way, to include the Raman lidar was to combine the observed vertical profile with the microwave radiometers in the retrieval. Here again, adding the Raman lidar improved the information content of the tomographic retrieval, but it did not significantly improve the accuracy of the retrieved field compared to the radiometer only retrieval. Therefore, although the tomographic technique did improve the information content and the accuracy of the solution in slow varying fields was good, the results in highly variable fields were disappointing.Comme la vapeur d'eau joue un rôle important dans l'atmosphère, plusieurs instruments pouvant mesurer des quantités de vapeur sont disponibles aux scientifiques. Un tel instrument est le radiomètre à microondes qui peut fournir des données sur les profils de vapeur d'eau à basse résolution. Par contre, dans le cas d'études portant sur la couche limite ou sur l'initiation de la convection, la résolution requise par la communauté scientifique est au-delà des capacités courantes des instruments. Par conséquent, des techniques de mesure ont été développées pour combler le fossé. Une de ces techniques de mesure est la tomographie. Le but de cette technique est de combiner plusieurs instruments du même genre, qui fournissent des mesures à faible résolution en portée ou des mesures intégrées, de sorte qu'ils fournissent des informations sur des trajets qui se croisent. Ce qui permet de fournir des mesures à plus haute résolution. Cette technique a été utilisée en météorologie pour mesurer des champs de vapeur d'eau et de nuages.Dans cette étude, nous avons examiné la performance du recouvrement tomographique d'un champ de vapeur d'eau 2D en utilisant la radiométrie microonde à partir du sol. Vu que la tomographie microondes exige aux radiomètres de balayer près du sol afin de fournir des mesures de la vapeur d'eau en surface, nous avons commencé par examiner les biais qui se produisent lors du balayage à ces basses altitudes. Les biais peuvent être causées par la largeur du faisceau d'antenne, la largeur des canaux et les modèles de propagation utilisés dans le modèle de l'instrument. Il a été constaté que les biais causés par la largeur du faisceau sont plus importants que ceux causés par la largeur des canaux. Ensuite, nous avons évalué le contenu de l'information et de l'exactitude du recouvrement tomographique avec les radiomètres microondes. L'impact des différentes caractéristiques des instruments (nombre de fréquences et les angles d'élévation) et de la configuration des instruments (le nombre d'instrument et l'espacement entre eux) sur la solution tomographique a été évaluée. Bien que l'utilisation de plusieurs instruments dans une configuration tomographique a amélioré le contenu de l'information du recouvrement, la précision du champ a été limitée par la nature passive de la mesure radiométrique, en particulier dans le cas des champs de vapeur d'eau très variables.Enfin, nous avons étudié l'impact de l'ajout d'un lidar Raman au recouvrement tomographique microondes. Ceci a été fait avec l'espoir que l'ajout un instrument de télédétection actif aiderait au recouvrement des champs variables. Trois différentes façons d'inclure le lidar Raman ont été essayées. La façon la plus simple, et la meilleure, d'inclure le lidar Raman était de combiner le profil vertical observé par le lidar avec les données des radiomètres microondes dans le recouvrement. L'ajout du lidar Raman a amélioré le contenu de l'information du recouvrement tomographique. Cependant, ceci n'a pas amélioré la précision du champ recouvré de manière significative par rapport au recouvrement qui utilise seulement les radiomètres. Par conséquent, bien que la technique tomographique a amélioré le contenu de l'information et que la précision de la solution du recouvrement dans le cas des champs lisses est bonne, les résultats dans des champs variables sont décevants.
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Aura, Stella M. (Stella Marris). "Fresh water forcing of the North Atlantic." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56641.
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Several numerical experiments are carried out using the Bryan-Cox Ocean General Circulation Model to investigate the variability of the North Atlantic thermohaline circulation under steady, non-zonal, surface forcing and realistic geometry. To this end the annual mean surface forcing fields were derived from the climatological data sets of Levitus (1982), Hellerman and Rosenstein (1983) and, Schmitt et al. (1989). Further, Arctic freshwater flux, an important part of the hydrological cycle within the North Atlantic Deep Water formation region, is taken into account.It is found that under present-day climatological surface forcing the system may oscillate at interdecadal period. The mechanism driving the oscillations is linked to changes in both the horizontal and vertical extent of convection in the northern "Labrador Sea". The structure of the surface freshwater flux forcing plays a major role in both the initiation and sustenance of the interdecadal oscillations. Allowing for a freshwater flux into the northern region of the "Labrador Sea" inhibits the interdecadal variability. The oscillations, however, appear, relatively insensitive to Arctic fresh water transport into the "Greenland Sea".
A detailed three-dimensional discussion of the physics behind the interdecadal oscillations is presented.
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Cramer, J., B. Biggs, J. Contapay, A. Iskandar, and A. Mahan. "A SMALL SATELLITE FOR MEASURING ATMOSPHERIC WATER CONTENT; PART I, DOWNLINK AND COMMAND SYSTEMS." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607662.
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International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis student paper was produced as part of the team design competition in the University of Arizona course ECE 485, Radiowaves and Telemetry. It describes a telemetering system design recommendation for a small satellite capable of conducting scientific research regarding atmospheric water content. This paper focuses on the subsystems required to send the scientific data and monitored operational conditions from the satellite to, and commands to the satellite from, a ground station. A companion paper (Hittle, et. al.) focuses on the cross-link subsystem required to make the scientific measurements and on the power generation and distribution subsystem for the satellite.
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THOMASON, LARRY WILLIS. "EXTINCTION OF NEAR INFRARED SOLAR RADIATION AS A MEANS FOR REMOTE DETERMINATION OF ATMOSPHERIC WATER VAPOR." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188078.
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A computationally efficient and accurate model is derived for the calculation of the atmospheric transmittance along inhomogeneous paths and within spectral bands dominated by molecular line absorption. It is a Stieltjes integration of transmission weighted by the frequency of occurrence of absorption coefficient within the band. Path inhomogeneitites are accounted for by assuming that the rank of absorption coefficient at any wavenumber is independent of temperature and pressure. The technique is then applied to the ground based radiometric determination of precipitable water. It is found that the technique predicts the behavior of the ρστ water vapor absorption band very well. An RMS disagreement of 11% is found when the model predictions are compared to radiosonde determinations of precipitable water. The model is also applied to the determination of vertical water vapor distributions in the stratosphere given measured effective optical depths as a function of tangent height from a limb scanning satellite. A new iterative reduction technique is introduced which incorporates the transmission model and it is shown to be both numerically stable and rapidly convergent. A comparison of the results with an independent reduction technique shows good overall agreement with a small systematic difference above 20 km. The uncertainty in the measurements, which yields solution uncertainties on the order of 30%, renders this systematic difference unimportant.
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Reichert, Andreas [Verfasser], and Bernhard [Akademischer Betreuer] Mayer. "Quantification of the infrared water vapor continuum by atmospheric measurements / Andreas Reichert ; Betreuer: Bernhard Mayer." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2016. http://d-nb.info/1123957398/34.
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Bonazza, Mattia [Verfasser]. "Water vapor, precipitation and evapotranspiration isotopic composition in the tropical atmospheric boundary layer / Mattia Bonazza." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2021. http://d-nb.info/123249268X/34.
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Hanley, Thomas Ryan. "The microwave opacity of ammonia and water vapor: application to remote sensing of the atmosphere of Jupiter." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24673.
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Thesis (Ph.D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008.Committee Chair: Dr. Paul G. Steffes; Committee Member: Dr. Gregory D. Durgin; Committee Member: Dr. Robert D. Braun; Committee Member: Dr. Thomas K. Gaylord; Committee Member: Dr. Waymond R. Scott
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Hittle, K., A. Braga, R. Ackerman, F. Afouni, H. Khalid, J. Coleman, T. Keena, and A. Page. "A SMALL SATELLITE FOR MEASURING ATMOSPHERIC WATER CONTENT; PART II, CROSSLINK AND DATA COLLECTION." International Foundation for Telemetering, 2001. http://hdl.handle.net/10150/607693.
Full textAbstract:
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, NevadaThis student paper was produced as part of the team design competition in the University of Arizona course ECE 485, Radiowaves and Telemetry. It describes a telemetering system design recommendation for a small satellite capable of conducting scientific research regarding atmospheric water content. This paper focuses on the cross-link subsystem required to make the scientific measurements and on the power generation and distribution subsystem for the satellite. A companion paper (Cramer, et. al.) focuses on the subsystems required to send the scientific data and monitored operational conditions from the satellite to, and commands to the satellite from, a ground station. The central objective is to validate a new technique for precisely measuring water vapor profiles of clouds throughout the troposphere. This method involves the detection of 4 SHF tones sent out from the International Space Station (ISS), providing high-resolution amplitude and phase delay data.
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Fullick, Simon Geoffrey. "Energy Balance Models With Three Phases Of Water Feedback." Thesis, University of Canterbury. Physics and Astronomy, 2014. http://hdl.handle.net/10092/9440.
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Simple one-dimensional heat balance equations have been used to understand climate concepts since the 1960s, when a class of models was developed known as energy balance models (EBMs). EBMs use the growth or loss of polar surface ice as a climatic feedback, giving rise to surprisingly complex non-linear behaviours. One aspect of EBMs that has been relatively poorly examined is the effects of feedbacks caused by the other two phases of water in Earth’s climate other than ice: water clouds and water vapour. Cloud and water vapour play a critical role in the energy balance of Earth’s climate, and yet are some of the least well understood elements of the global climate system. This thesis explores the behaviour and interrelationships of climatic feedbacks caused by water in all three phases as it exists in the climate: surface ice caps, water vapour, and liquid water clouds. A two-layered EBM was modified with parameterizations of water vapour and liquid water clouds in order to conduct experiments. Three variants of the model were produced, each with progressively more water feedbacks than the last: a 1 phase model (with only surface ice feedback), a 2 phase model (with surface ice and water vapour) and a 3 phase model (with surface ice, water vapour, and cloud). The models were found to give generally realistic results, but with an underestimation of water vapour density, which in turn reduced the generated cloud fraction in the 3 phase model. Thus, the impacts of these extra feedbacks were likely to be underestimated in the analysis in general. The sensitivity of the model to several prognostic variables was studied by observing the changes in the model to a range of each variable. The 3 phase model was less sensitive to changes to the solar constant, S0, which measures incoming solar radiation, than the 1 phase model. This was probably caused by cloud reflecting and absorbing some radiation from the sun that would have otherwise reached the surface, changing the ratio of atmospheric heat transport to surface heat transport from 2.4953 for the 1 phase model to 2.0626 for the 3 phase model. Changing surface and ice albedo values resulted in changes in the model’s stability. The model was found to be insensitive to changes in surface humidity that drives the amount of water vapour the system has available, due to underestimation of water vapour in the model. The stability of the model was examined, and the 1 phase model was found to respond faster to changes in S0 than the 3 phase model. The model was tested for hysteresis, which was confirmed for all three model variants. The 1 phase model showed less stability then the 3 phase model as S0 was increased, but both models were similarly stable as S0 was decreased.
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Sun, De-Zheng. "Tropical tropospheric water vapor budget, maintenance of the lapse rate, and distribution of the extratropical tropospheric temperature and wind." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/58425.
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Friedman, Karen S. (Karen Samard). "Global atmospheric water vapor flux climatology in the NCEP/NCAR reanalysis and the Oort data set." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/10371.
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Horvath, Akos. "Differences between satellite measurements and theoretical estimates of global cloud liquid water amounts." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280553.
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This dissertation investigated the estimation of global cloud water amounts. The study was prompted by the large discrepancy in published global mean values of cloud liquid water path. Microwave and optical satellite measurements of this quantity range from 25 g/m² to 80 g/m². Theoretical estimates are significantly larger with a current best guess value of 380 g/m². The major limitations of microwave measurements were found to be the inadequate separation of the cloud- and rainwater components, and the lack of retrievals over land. Optical observations were found to be constrained by the truncation of retrieved optical thickness due to saturation effects, the limited knowledge of drop effective radius as a function of optical thickness and rain rate, and plane-parallel retrieval errors due to 3D effects. An analysis of the potential uncertainties concluded that the current theoretical estimate of the global mean cloud liquid water path of 380 g/m² was reasonable with an uncertainty of ±80 g/m². Errors in the optical retrievals due to 3D effects were estimated using a multiangle data set. A microwave-optical comparison revealed that a drop effective radius significantly larger than the common assumption of 8-10 μm was required to remove the low bias of optical retrievals of cloud liquid water in precipitating systems. The low bias due to saturation effects was accounted for by sigmoidal extrapolation of the cumulative distribution of cloud optical thickness. Overall it was found that the optical measurement of the global mean cloud liquid water path could be increased to a maximum of 150 g/m² over the oceans. The failure to close the gap between satellite measurements and theoretical estimates can partly be attributed to, but cannot be completely explained by, the lack of the most intense continental clouds in the ocean-only data set used in this study. It is unlikely that optical measurements can be corrected to accurately retrieve the largest liquid water amounts. New techniques are required to handle the wettest precipitating clouds.
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Rowe, Penny. "Measurements of the foreign-broadened continuum of water vapor in the 6.3 micron band at -30 celsius /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/8604.
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Karpowicz, Bryan Mills. "In search of water vapor on Jupiter: laboratory measurements of the microwave properties of water vapor and simulations of Jupiter's microwave emission in support of the Juno mission." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33947.
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This research has involved the conduct of a series of laboratory measurements of the centimeter-wavelength opacity of water vapor along with the development of a hybrid radiative transfer ray-tracing simulator for the atmosphere of Jupiter which employs a model for water vapor opacity derived from the measurements. For this study an existing Georgia Tech high-sensitivity microwave measurement system (Hanley and Steffes , 2007) has been adapted for pressures ranging from 12-100 bars, and a corresponding temperature range of 293-525°K. Water vapor is measured in a mixture of hydrogen and helium. Using these measurements which covered a wavelength range of 6--20 cm, a new model is developed for water vapor absorption under Jovian conditions. In conjunction with our laboratory measurements, and the development of a new model for water vapor absorption, we conduct sensitivity studies of water vapor microwave emission in the Jovian atmosphere using a hybrid radiative transfer ray-tracing simulator. The approach has been used previously for Saturn (Hoffman, 2001), and Venus (Jenkins et al., 2001).
This model has been adapted to include the antenna patterns typical of the NASA Juno Mission microwave radiometer (NASA/Juno -MWR) along with Jupiter's geometric parameters
(oblateness), and atmospheric conditions. Using this adapted model we perform rigorous sensitivity tests for water vapor in the Jovian atmosphere. This work will directly improve our understanding of microwave absorption by atmospheric water vapor at Jupiter, and improve retrievals from the Juno microwave radiometer. Indirectly, this work will help to refine models for the formation of Jupiter and the entire solar system through an improved understanding of the planet-wide abundance of water vapor which will result from the successful opreation of the Juno Microwave Radiometer (Juno-MWR).
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Cheng, Yufu. "Effects of manipulated atmospheric carbon dioxide concentrations on carbon dioxide and water vapor fluxes in Southern California chaparral /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Thesis (Ph. D.)--University of California, Davis and San Diego State University, 2003.Includes bibliographical references (leaves 95-101). Also available via the World Wide Web. (Restricted to UC campuses).
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Taniguchi, Kyoko. "Characterization of water vapor within the planetary boundary layer based on the ARM raman lidar observation at the SGP site." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1445054161&sid=18&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Lu, Cuixian [Verfasser], Harald [Akademischer Betreuer] Schuh, Gunnar [Gutachter] Elgered, and Robert [Gutachter] Weber. "Real-time sensing of atmospheric water vapor from multi-GNSS constellations / Cuixian Lu ; Gutachter: Gunnar Elgered, Robert Weber ; Betreuer: Harald Schuh." Berlin : Technische Universität Berlin, 2016. http://d-nb.info/1156273838/34.
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Roell, Marilee May. "Observed decadal variations of the zonal mean hygropause and its relationship to changes in the transport barrier." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45808.
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This study examines the long-term record of lower stratospheric water vapor focusing on the 20-year data record from the Stratospheric Aerosol and Gas Experiment II (SAGE II). The SAGE II zonal monthly mean water vapor data was enhanced to include the aerosol heavy late 1980s through the use of aerosol extinction filtering of the data. Comparisons between the SAGE II lower stratospheric water vapor and the Limb Infrared Monitor of the Stratosphere (LIMS), the Microwave Limb Sounder (MLS), and HALogen Occultation Experiment (HALOE) are performed. This study further focuses on the minimum lower stratospheric water vapor (i.e., hygropause) and on the dehydration seen in the hygropause with examination of the transport barrier at both the tropical tropopause and the tropopause folding region between the tropics and extra-tropics that would account for this decadal variation.
The effects of aerosol contamination on the SAGE II water vapor retrievals from four volcanic eruptions from 1984 to 1992 were examined, leading to a four level filtering of the SAGE II water vapor data to allow retention of good data from early in the data record. With the improved filtered water vapor data, monthly and seasonal time series analyses show a significant decadal variation in the lower stratosphere for all months where the satellite coverage provided data from the late 1980s to the early 2000s. This decadal variation documents a decrease in the water vapor from below approximately 25 km to below the tropopause with this decrease seen in the hygropause from the tropics to the poles.
Analysis of the hygropause for all months provided a statistically significant consistent neutral or decreasing value in the long-term water vapor minimum. March was shown to be the seasonal minimum in the hygropause over this 20-year low aerosol record, followed by a discontinuity in the minimum abundance after 2000. Three transport pathways for transport of water vapor from the moist troposphere to the lower stratosphere include the tropical tropopause, isentropic transport at the sub-tropical jet locations, and meridional transport from the tropics to the midlatitudes above the hygropause.
The tropical tropopause temperatures were examined using the new Modern Era Retrospective-analysis for Research and Applications (MERRA) data set. Analysis showed a significant decrease in the tropical and sub-tropical tropopause temperatures over the 20-year timeframe for the DJF season preceding the March minimum. The lower temperatures would provide a colder "cold trap" at the tropopause, further "freeze drying" the air seasonally transported from the upper troposphere to the lower stratosphere, providing the long-term dehydration in the hygropause and lower stratosphere.
The Ertel's Potential Vorticity (EPV or PV) was examined as a proxy for the sub-tropical jet movement towards the poles over this long-term record. Changes in this pathway location may affect the efficiency of isentropic transport of moist tropospheric air into the lower stratosphere at these higher latitudes. Analysis using the MERRA zonal EPV and maximum zonal Uwind data showed a statistically significant shift in the locations of the contours towards the SH poles over this 20-year timeframe for the DJF, DJFM seasons and the month of December. The meridional winds above the tropopause show an increase over the 20-year record covered by SAGE II water vapor data. These increasing winds are consistent with the increase in the Brewer-Dobson circulation shown in other studies. The colder tropopause temperatures along with the increasing Brewer-Dobson circulation just above the tropopause, are the likely cause for the decreasing water vapor trend as seen in the SAGE II March hygropause over the 20-years from 1986-2005.
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Nascimento, Cristina Rodrigues. "Correção atmosferica de imagens do sensor AVHRR/NOAA utilizando produtos atmosfericos do sensor MODIS/TERRA." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257080.
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Orientador: Jurandir Zullo JuniorDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
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Resumo: O sensoriamento remoto nas regiões espectrais do visível e do infravermelho próximo constitui uma das ferramentas mais importantes para o entendimento da biosfera e de suas dinâmicas. Entretanto, estas duas regiões são afetadas pelos efeitos atmosféricos tais como, o espalhamento e a absorção,ocasionados por sua vez pelos aerossóis e gases atmosféricos. Na tentativa de obter o fator de reflectância bi-direcional da superfície terrestre, nos canais 1 e 2 do sensor AVHRR, foi realizada a correção atmosférica, baseada na entrada de dados, tais como espessura óptica dos aerossóis, coluna total de vapor d?água e carga total de ozônio, respectivamente fornecidos pelo sensor MODIS. O intuito da utilização deste sensor está diretamente relacionado à obtenção das informações, necessários para a correção atmosférica, considerando-se a variabilidade dos parâmetros no tempo e no espaço. Para tanto foi utilizado o aplicativo SCORADIS, fundamentado no modelo de transferência radiativa 5S, então adaptado, para possibilitar a correção atmosférica de toda a imagem do AVHRR a partir da entrada das imagens correspondentes aos planos atmosféricos, através da utilização de quatro metodologias distintas de correção atmosférica. As análises realizadas indicaram que as correções realizadas a partir dos dados atmosféricos do sensor MODIS apresentaram resultados coerentes com o esperado após a eliminação dos efeitos de espalhamento e de absorção atmosférica, nos canais 1 e 2 do NOAA-17, nas duas datas consideradas (14/07/2004 e 30/08/2005). Para o NDVI, a diferença percentual entre as imagens com e sem correção chegaram a ser de, aproximadamente, 60%, o que ressalta a importância da correção atmosférica destes canais, principalmente no acompanhamento da vegetação a partir de imagens multitemporais. Não se observou diferença significativa entre as metodologias utilizadas para a entrada dos dados atmosféricos no sistema de correção atmosférica, devido, possivelmente, à magnitude dos valores utilizados e à áreateste escolhida. Os produtos obtidos a partir das imagens do MODIS mostraram potencial para utilização na estimativa dos principais parâmetros atmosféricos necessários para a correção atmosférica (como a espessura óptica dos aerossóis e conteúdo de vapor d'água e ozônio) e que são de grande dificuldade para obtenção em campo
Abstract: Remote sensing in the spectral regions of visible and infrared is one of the most important techniques used for studying the biosphere. However these two spectral regions are affected by atmospheric effects as scattering and absorption, caused by aerosols and atmospheric gases. In the attempt to obtain the real reflectance of ground surface, in channels 1 and 2 of AVHRR sensor, was performed the atmospheric correction of two NOAA images acquired on July/14/2004 and August/30/2005, based on atmospheric data supplied by the MODIS sensor, considering the spatial and temporal variability of these parameters. The system SCORADIS, based on the radiative transfer model called 5S, was adapted to read images having values of aerosols optical thickness, water vapor content and ozone contents corresponding spatially to each pixel of a AVHRR/NOAA image. Four distinct methodologies were used to define the images of atmospheric parameters. Coherent results were obtained using atmospheric data from MODIS, indicating that the scattering and absorption effects were correctly eliminated from the NOAA images in the two dates considered. The difference between the NDVI calculated with corrected and noncorrected images was up to 60%, showing the importance of using corrected images in applications based on multitemporal images. There was not observed significant difference among the four methodologies applied to define the atmospheric data used in the atmospheric correction system due, maybe, to the magnitude of the values and to the atmospheric conditions of test-area. The atmospheric products from MODIS can be used to defining the input data (like aerosol optical thickness, water vapor contents and ozone contents) for the atmospheric correction systems of AVHRR/NOAA images
Mestrado
Planejamento e Desenvolvimento Rural Sustentável
Mestre em Engenharia Agrícola
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Nehrir, Amin Reza. "Development of an eye-safe diode-laser-based micro-pulse differential absorption lidar (mp-DIAL) for atmospheric water-vapor and aerosol studies." Diss., Montana State University, 2011. http://etd.lib.montana.edu/etd/2011/nehrir/NehrirA0811.pdf.
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This dissertation describes the design, construction, and testing of an all diode-laser-based water-vapor differential absorption lidar (DIAL) instrument through two distinct stages of development. A second generation low pulse energy, high pulse repetition frequency DIAL instrument was developed to overcome the power limitations of the first generation instrument which required unrealistic integration times approaching 1 hour. The second generation DIAL transmitter used a custom built external cavity diode laser (ECDL) as the seed source for an actively current pulsed tapered semiconductor optical amplifier (TSOA), yielding a maximum output transmitter pulse energy of 2 microjoules over a 1 microsecond duration pulse width at a 20 kHz pulse repetition frequency, decreasing the required integration Period to approximately 20-30 minutes. Nighttime and daytime water-vapor profiles were collected with the second generation DIAL instrument which showed good agreement with collocated radiosonde measurements from near the surface up to the top of the planetary boundary layer. Aerosol optical properties were also measured using the calibrated offline channel returns using the iterative Fernald solution to the lidar equation. Most recently, a third generation DIAL transmitter has been developed to further increase the output pulse energy and to also decrease the DIAL atmospheric spectral sampling time. Two custom built high power ECDL's and an electro-mechanical based fiber optic switch are used to sequentially seed a single stage actively current pulsed TSOA in order to minimize the systematic errors introduced in the DIAL retrievals resulting from air-mass miss-sampling between the two DIAL wavelengths. Peak output pulse energies of 7 microjoules have been measured over 1 microsecond pulse durations at a 10 kHz pulse repetition frequency with a 1-6 second DIAL spectral switching time, further decreasing the total required integration period to 20 minutes for both nighttime and daytime operation. The increased performance of the third generation transmitter has allowed for nighttime and daytime water vapor profiling under varying atmospheric conditions that shows good agreement with collocated radiosonde measurements up to ~ 6 km and ~ 3 km, respectively. A detailed description of the second and third generation DIAL instrument performance as well as data retrievals are presented in this dissertation. Future work to improve the current third generation DIAL instrument for full-time autonomous measurements of atmospheric water-vapor and aerosols is also discussed.
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Leinweber, Ronny [Verfasser]. "Remote sensing of atmospheric water vapor over land areas using MERIS measurements and application to numerical weather prediction model validation / Ronny Leinweber." Berlin : Freie Universität Berlin, 2010. http://d-nb.info/1024743845/34.
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Martinez, Agudelo John Alejandro. "On the Hydroclimate of Southern South America: Water Vapor Transport and the Role of Shallow Groundwater on Land-Atmosphere Interactions." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/595679.
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The present work focuses on the sources and transport of water vapor to the La Plata Basin (LPB), and the role of groundwater dynamics on the simulation of hydrometeorological conditions over the basin. In the first part of the study an extension to the Dynamic Recycling Model (DRM) is developed to estimate the water vapor transported to the LPB from different regions in South America and the nearby oceans, and the corresponding contribution to precipitation over the LPB. It is found that more than 23% of the precipitation over the LPB is from local origin, while nearly 20% originates from evapotranspiration from the southern Amazon. Most of the moisture comes from terrestrial sources, with the South American continent contributing more than 62% of the moisture for precipitation over the LPB. The Amazonian contribution increases during the positive phase of El Niño and the negative phase of the Antarctic Oscillation. In the second part of the study the effect of a groundwater scheme on the simulation of terrestrial water storage, soil moisture and evapotranspiration (ET) over the LPB is investigated. It is found that the groundwater scheme improves the simulation of fluctuations in the terrestrial water storage over parts of the southern Amazon. There is also an increase in the soil moisture in the root zone over those regions where the water table is closer to the surface, including parts of the western and southern Amazon, and of the central and southern LPB. ET increases in the central and southern LPB, where it is water limited. Over parts of the southeastern Amazon the effects of the groundwater scheme are only observed at higher resolution, when the convergence of lateral groundwater flow in local topographical depressions is resolved by the model. Finally, the effects of the groundwater scheme on near surface conditions and precipitation are explored. It is found that the increase in ET induced by the groundwater scheme over parts of the LPB induces an increase in near surface specific humidity, accompanied by a decrease in near surface temperature. During the dry season, downstream of the regions where ET increases, there is also a slight increase in precipitation, over a region where the model has a dry bias compared with observations. During the early rainy season, there is also an increase in the local convective available potential energy. Over the southern LPB, groundwater induces an increase in ET and precipitation of 13 and 10%, respectively. Over the LPB, the groundwater scheme tends to improve the warm and dry biases of the model. It is suggested that a more realistic simulation of the water table depth could further increase the simulated precipitation during the early rainy season.
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Honaman, Andrew M. 1958. "The potential and actual evapotranspiration of water-rich ecosystems in arid regions." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/291843.
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The well-known and widely accepted Penman combination equation was applied to climatic data collected in a desert environment to predict actual evapotranspiration if the desert region were developed into irrigated agriculture. The Penman evaporation estimates from desert climate data were compared to Bowen ratio ET measurements collected on irrigated alfalfa fields in the general vicinity. Six variations of the wind function in Penman's equation were tested. From these six the best fit-model was determined. surprisingly, Penman's original equation provided the best fit (in mean hourly units W m⁻²) as PLE₁ = 0.953LE + 43. The s.e. was 51 W⁻², r² = 0.953, and n = 298 hourly points. A calibrated wind function was developed and named 'Sonoran'. The Sonoran wind function PLE₆ = 0.954LE + 24, s.e. = 48.8 r² = 0.956 provided virtually imperceptible improvements over Penman's original wind function.
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Wijenayaka, A. K. Lahiru Anuradha. "Investigation of the atmospheric processing of α-FeOOH containing aerosols with water and HNO3: reactivity, fate, and consequences and the impact of particle size on surface adsorption and particle solubility." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/2789.
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The atmosphere is a heterogeneous system which is rich in potential chemistry. The processes taking place within this system as well as at the interface of its constituents are of immense importance in understanding how the atmosphere in turn can impact the well-being of all living on the surface of earth. Thus, the heterogeneous chemistry of atmospheric aerosols has since long been subjected to extensive scientific investigation, in view of broadening our understanding of this imperative system.
In this study, the heterogeneous interactions of water vapor and gaseous HNO3 on goethite (a-FeOOH), a prominent component of mineral dust aerosol is investigated with quartz crystal microbalance (QCM) measurements and attenuated total reflectance - Fourier transform IR (ATR-FTIR) spectroscopy. Laboratory synthesized goethite samples of varying size (microrods of specific surface area 34 m2/g and nanorods of specific surface area 121 m2/g) were used in order to identify the size dependent interaction of goethite with H2O and HNO3. The study revealed that the exposure of goethite to gas phase H2O and HNO3 results in the uptake of these gases via surface adsorption. Additionally, this novel combined approach of QCM and ATR-FTIR spectroscopy allowed for quantification of the amount of uptake while the spectroscopic data provided information on the speciation of adsorbed products. Thus, with the QCM and spectroscopic data in hand, a precise interpretation of the reactivity as well as its size dependence was sought. In a general sense, the reactivity of a substance is believed to increase with decreasing particle size. The results of this investigation show that in the case of H2O, both microrods and nanorods take up water while the total amount of adsorbed water, when normalized to surface area, is similar for both particle sizes. However, for HNO3, the saturation coverage of total and irreversibly bound HNO3 on microrods was observed to be higher than that on nanorods. With supplementary analysis, this anomalous size effect was attributed to structural features such as the involvement of surface hydroxyl groups in determining the reactivity, which would be subjected to change as a function of particle size. Furthermore, an investigation of the behavior of HNO3 reacted goethite in aqueous media and the uptake of H2O and HNO3 at their mutual presence was carried out such as to better understand the effects of atmospheric processing upon dispersal within the hydrosphere. Further analysis is warranted before arriving at a general conclusion on the size-dependent reactivity of goethite. However, we may argue that goethite containing aerosols may indicate the same pattern of reactivity within the atmosphere as that observed here. Thus, the inference of this investigation proves to be significant in broadening our understanding of this atmosphere as well as the entire biosphere as a whole.
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Caramori, Paulo Henrique. "Structural analysis of airborne flux traces and their link to remote sensing of vegetation and surface temperature." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41012.
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This thesis examines the link between airborne flux estimates of CO$ sb2$, sensible heat, and water vapor, and surface parameters retrieved by remote sensing. Chapter 1 analyses the relationship between surface temperature and vegetation indices, obtained from the Advanced Very High Resolution Radiometer on board of NOAA-9 and -10 satellites, and fluxes of sensible heat, latent heat, and CO$ sb2$, estimated from aircraft. Linear relationships between CO$ sb2$ and the Normalized Difference Vegetation Index (NDVI) or the Simple Ratio vegetation index (SR) are found on a daily basis, but a highly nonlinear relationship appears for the seasonal variation. Latent Heat fluxes showed the poorest correlations with surface parameters. A seasonal linear relationship appeared between sensible heat and NDVI. Local extreme flux values due to the intermittency of boundary layer dynamics largely contribute to lower the correlations; such variations are the reason for the difficulties in relating fluxes obtained from single overpasses and over short distances to fixed points at the surface. This problem is further examined in Chapter 2, in which conditional sampling of airborne flux estimates is used to characterize the turbulent structures that are carrying flux, and their link to the surface. The analysis confirms that few extreme events may carry a significant fraction of the flux. Missing or hitting one of these structures may translate into very large oscillations on the flux estimate that are often not directly coupled to surface characteristics. A much clearer surface 'signature' emerges when measurements are taken within the surface layer, since the reorganization of turbulent structures that takes place with increasing height will result in a merging of the signature that came from different sources at the surface. This helps to explain some of the poor correlations obtained in Chapter 1 and reinforces the need for a better understanding of the distributions of these tu
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Brown, Abel K. "A global GPS data reprocessing strategy: Implications for the reference frame, orbital solutions, and trends in zenith delay parameters and total column water vapor (1994 - 2011)." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322627557.
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Killian, Marie Coy. "Kinetics of Atmospheric Reactions of Biogenic Volatile Organic Compounds: Measurement of the Rate Constant ofThujone + Cl· at 296 K and Calculation ofthe Equilibrium Constant for the HO2CH2CH2O2· H2O Complex." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3642.
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Biogenic volatile organic compounds (VOCs) react with Cl and OH radicals and the resulting radicals combine with oxygen to form peroxy radicals RO2. Organic peroxy radicals can then react with NO to form NO2, a precursor of tropospheric ozone. The work presented here explored the initial reaction between Cl and thujone, a VOC emitted by Great Basin sagebrush. The rate constant for the reaction of thujone + Cl at 296 K was measured with the method of relative rates with FTIR for detection of reactants. LEDs were used to photolyze Cl2 to generate Cl in the reaction cell. Thujone was also photolyzed by the LEDs and therefore the relative rates model was revised to account for this photolysis. With toluene as the reference compound, the rate constant for thujone + Cl at 296 K is 2.62 ± 1.90 × 10-12 molecules-1 s-1, giving an atmospheric lifetime of 0.5--2.6 minutes for thujone. Cline et al. showed that the rate of the self-reaction of HO2CH2CH2O2 (β-HEP) increases in the presence of water vapor. This enhancement has a strong temperature dependence with a greater enhancement observed at colder temperatures. The observed rate enhancement has been attributed to the formation of a β-HEP--H2O complex. In this work, the equilibrium constant for the formation of the β-HEP--H2O complex was calculated by ab initio calculations. Given the energy available at room temperature, the complex will populate three local minimum geometries and β-HEP will populate two local minimum geometries. The partition function for each of these geometries was calculated and used to calculate the equilibrium constant for complex formation as a function of temperature. Based on these computational results, the observed temperature dependence for the rate enhancement can be attributed to the strong temperature dependence for the rate constant of the reaction of β-HEP--H2O + β-HEP rather than the temperature dependence of complex formation.