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1

Research on experiments and action mechanism with water vapor as coolant and lubricant in Green cutting  

Microsoft Academic Search

Green cutting has become focus of attention in ecological and environmental protection. Water vapor is cheap, pollution-free and eco-friendly. Therefore water vapor is a good and economical coolant and lubricant. Water vapor generator and vapor feeding system were developed to generate and feed water vapor. Comparative experiments were carried out in witch YT15 (P type in ISO) tool was used

Junyan Liu; Rongdi Han; Yongfeng Sun

2005-01-01

2

A Simple Experiment for Determining Vapor Pressure and Enthalpy of Vaporization of Water.  

ERIC Educational Resources Information Center

Laboratory procedures, calculations, and sample results are described for a freshman chemistry experiment in which the Clausius-Clapeyron equation is introduced as a means of describing the variation of vapor pressure with temperature and for determining enthalpy of vaporization. (Author/SK)

Levinson, Gerald S.

1982-01-01

3

Increases in middle atmospheric water vapor as observed by the Halogen Occultation Experiment and the ground-based Water Vapor Millimeter-wave Spectrometer from 1991 to 1997  

Microsoft Academic Search

Water vapor measurements made by the Halogen Occultation Experiment (HALOE) from 1991 to 1997 are compared with ground-based observations by the Water Vapor Millimeter-wave Spectrometers (WVMS) taken from 1992 to 1997 at Table Mountain, California (34.4°N, 242.3°E), and at Lauder, New Zealand (45.0°S, 169.7°E). The HALOE measurements show that an upward trend in middle atmospheric water vapor is present at

Gerald E. Nedoluha; Richard M. Bevilacqua; R. Michael Gomez; David E. Siskind; Brian C. Hicks; James M. Russell; Brian J. Connor

1998-01-01

4

Algorithms and sensitivity analyses for Stratospheric Aerosol and Gas Experiment II water vapor retrieval  

NASA Technical Reports Server (NTRS)

The operational inversion algorithm used for the retrieval of the water-vapor vertical profiles from the Stratospheric Aerosol and Gas Experiment II (SAGE II) occultation data is presented. Unlike the algorithm used for the retrieval of aerosol, O3, and NO2, the water-vapor retrieval algorithm accounts for the nonlinear relationship between the concentration versus the broad-band absorption characteristics of water vapor. Problems related to the accuracy of the computational scheme, the accuracy of the removal of other interfering species, and the expected uncertainty of the retrieved profile are examined. Results are presented on the error analysis of the SAGE II water vapor retrieval, indicating that the SAGE II instrument produced good quality water vapor data.

Chu, W. P.; Chiou, E. W.; Larsen, J. C.; Thomason, L. W.; Rind, D.; Buglia, J. J.; Oltmans, S.; Mccormick, M. P.; Mcmaster, L. M.

1993-01-01

5

Increases in middle atmospheric water vapor as observed by the Halogen Occultation Experiment and the ground-based Water Vapor Millimeter-wave Spectrometer from 1991 to 1997  

Microsoft Academic Search

Water vapor measurements made by the Halogen Occultation Experiment (HALOE) from 1991 to 1997 are compared with ground-based observations by the Water Vapor Millimeter-wave Spectrometers (WVMS) taken from 1992 to 1997 at Table Mountain, California (34.4øN, 242.3øE), and at Lauder, New Zealand (45.0øS, 169.7øE). The HALOE measurements show that an upward trend in middle atmospheric water vapor is present at

Gerald E. Nedoluha; Richard M. Bevilacqua; R. Michael Gomez; David E. Siskind; Brian C. Hicks; James M. Russell; Brian J. Connor

1998-01-01

6

NASA Experiment on Tropospheric-Stratospheric Water Vapor Transport in the Intertropical Convergence Zone  

NASA Technical Reports Server (NTRS)

The following six papers report preliminary results obtained from a field experiment designed to study the role of tropical cumulo-nimbus clouds in the transfer of water vapor from the troposphere to the stratosphere over the region of Panama. The measurements were made utilizing special NOAA enhanced IR satellite images, radiosonde-ozonesondes and a NASA U-2 aircraft carrying. nine experiments. The experiments were provided by a group of NASA, NOAA, industry, and university scientists. Measurements included atmospheric humidity, air and cloud top temperatures, atmospheric tracer constituents, cloud particle characteristics and cloud morphology. The aircraft made a total of eleven flights from August 30 through September 18, 1980, from Howard Air Force Base, Panama; the pilots obtained horizontal and vertical profiles in and near convectively active regions and flew around and over cumulo-nimbus towers and through the extended anvils in the stratosphere. Cumulo-nimbus clouds in the tropics appear to play an important role in upward water vapor transport and may represent the principal source influencing the stratospheric water vapor budget. The clouds provide strong vertical circulation in the troposphere, mixing surface air and its trace materials (water vapor, CFM's sulfur compounds, etc.) quickly up to the tropopause. It is usually assumed that large scale mean motions or eddy scale motions transport the trace materials through the tropopause and into the stratosphere where they are further dispersed and react with other stratospheric constituents. The important step between the troposphere and stratosphere for water vapor appears to depend upon the processes occurring at or near the tropopause at the tops of the cumulo-nimbus towers. Several processes have been sugested: (1) The highest towers penetrate the tropopause and carry water in the form of small ice particles directly into the stratosphere. (2) Water vapor from the tops of the cumulonimbus clouds is transported somehow through the tropopause, the vapor pressure being controlled by the temperature at the tops of the clouds; the dryness of the stratosphere could be explained if most of the transport occurs in connection with very high clouds in regions with very high and cold tropopause. (3) Cumulo-nimbus anvils act as terrestrial-radiation shields allowing the ice particle temperatures near cloud tops to cool radiatively below the supersaturation point; this cooling would cause a vapor deposition on the ice particles which will settle out and thus act as water scavengers. The experiment was designed to collect information on these detailed physical processes near and above the tropopause in order to assess their importance and the role they play in controlling stratospheric water vapor humidity.

Page, William A.

1982-01-01

7

Measurement of the particulate and water vapor contamination environments of the Midcourse Space Experiment (MSX) spacecraft  

Microsoft Academic Search

We have designed, fabricated, and tested two flashlamp-based instruments that will characterize the particulate and water vapor contamination environments aboard the Midcourse Space Experiment (MSX) spacecraft: the Xenon Flashlamp and the Krypton Radiometer. These instruments will operate as part of suite of instruments to monitor the MSX contamination environment over its five-year mission. The Xenon Flashlamp illuminates particles in the

Gary E. Galica; John J. Atkinson; G. Aurilio; Orr Shepherd; Jeffrey C. Lesho; Mark T. Boies; Kevin J. Heffernan; P. J. McEvaddy; O. Manuel Uy

1994-01-01

8

Water Vapor Imagery: Water Vapor Imagery Basics  

NSDL National Science Digital Library

This self-paced, interactive tutorial enables learners to discover practical uses for water vapor imagery from weather satellites. The module introduces the concept and function of the water vapor channel of satellite imagery, and teaches how to interpret and apply data obtained from the water vapor channel. At the end of the tutorial, links are provided to real world data collected by NASA satellites where learners can apply the skills they have acquired. This resource is part of the tutorial series, Satellite Observations in Science Education, and is the first of three modules in the tutorial, Water Vapor Imagery. (Note: requires Java plug-in)

9

Raman lidar and sun photometer measurements of aerosols and water vapor during the ARM RCS experiment  

NASA Technical Reports Server (NTRS)

The first Atmospheric Radiation Measurement (ARM) Remote Cloud Study (RCS) Intensive Operations Period (IOP) was held during April 1994 at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This experiment was conducted to evaluate and calibrate state-of-the-art, ground based remote sensing instruments and to use the data acquired by these instruments to validate retrieval algorithms developed under the ARM program. These activities are part of an overall plan to assess general circulation model (GCM) parameterization research. Since radiation processes are one of the key areas included in this parameterization research, measurements of water vapor and aerosols are required because of the important roles these atmospheric constituents play in radiative transfer. Two instruments were deployed during this IOP to measure water vapor and aerosols and study their relationship. The NASA/Goddard Space Flight Center (GSFC) Scanning Raman Lidar (SRL) acquired water vapor and aerosol profile data during 15 nights of operations. The lidar acquired vertical profiles as well as nearly horizontal profiles directed near an instrumented 60 meter tower. Aerosol optical thickness, phase function, size distribution, and integrated water vapor were derived from measurements with a multiband automatic sun and sky scanning radiometer deployed at this site.

Ferrare, R. A.; Whiteman, D. N.; Melfi, S. H.; Evans, K. D.; Holben, B. N.

1995-01-01

10

Annual variations of water vapor in the stratosphere and upper troposphere observed by the Stratospheric Aerosol and Gas Experiment II  

NASA Technical Reports Server (NTRS)

Data collected by the Stratospheric Aerosol and Gas Experiment II are presented, showing annual variations of water vapor in the stratosphere and the upper troposphere. The altitude-time cross sections of water vapor were found to exhibit annually repeatable patterns in both hemispheres, with a yearly minimum in water vapor appearing in both hemispheres at about the same time, supporting the concept of a common source for stratospheric dry air. A linear regression analysis was applied to the three-year data set to elucidate global values and variations of water vapor ratio.

Mccormick, M. P.; Chiou, E. W.; Mcmaster, L. R.; Chu, W. P.; Larsen, J. C.; Rind, D.; Oltmans, S.

1993-01-01

11

LIMS Instrument Package (LIP) balloon experiment: Nimbus 7 satellite correlative temperature, ozone, water vapor, and nitric acid measurements  

NASA Technical Reports Server (NTRS)

The Limb Infrared Monitor of the Stratosphere (LIMS) LIP balloon experiment was used to obtain correlative temperature, ozone, water vapor, and nitric acid data at altitudes between 10 and 36 kilometers. The performance of the LIMS sensor flown on the Nimbus 7 Satellite was assessed. The LIP consists of the modified electrochemical concentration cell ozonesonde, the ultraviolet absorption photometric of ozone, the water vapor infrared radiometer sonde, the chemical absorption filter instrument for nitric acid vapor, and the infrared radiometer for nitric acid vapor. The limb instrument package (LIP), its correlative sensors, and the resulting data obtained from an engineering and four correlative flights are described.

Lee, R. B., III; Gandrud, B. W.; Robbins, D. E.; Rossi, L. C.; Swann, N. R. W.

1982-01-01

12

Implications of the Stratospheric Water Vapor Distribution as Determined from the Nimbus 7 LIMS Experiment.  

NASA Astrophysics Data System (ADS)

The LIMS experiment on Nimbus 7 has provided new results on the stratospheric water vapor distribution. The data show 1) a latitudinal gradient with mixing ratios that increase by a factor of 2 from equator to ±60 degrees at 50 mb, 2) most of the time there is a fairly uniform mixing ratio of 5 ppmv at high latitudes, but more variation exists during winter, 3) a well-developed hygropause at low to midlatitudes of the lower stratosphere 4) a source region of water vapor in the upper stratosphere to lower mesosphere that is consistent with methane oxidation chemistry, at least within the uncertainties of the data, 5) an apparent zonal mean H2O distribution that is consistent with the circulation proposed by Brewer in 1949, and 6) a zonal mean distribution in the lower stratosphere that is consistent with the idea of quasi-isentropic transport by eddies in the meridional direction. Limits to the use of the data in the refinement of our understanding of the stratospheric water vapor budget are noted.

Remsberg, Ellis; Russell, James M., III; Gordley, Larry L.; Gille, John C.; Bailey, Paul L.

1984-10-01

13

Overview of the Stratospheric Aerosol and Gas Experiment II water vapor observations - Method, validation, and data characteristics  

NASA Technical Reports Server (NTRS)

Results are presented of water vapor observations in the troposphere and stratosphere performed by the Stratospheric Aerosol and Gas Experiment II solar occultation instrument, and the analysis procedure, the instrument errors, and data characteristics are discussed. The results are compared with correlative in situ measurements and other satellite data. The features of the data set collected between 1985 and 1989 include an increase in middle- and upper-tropospheric water vapor during northern hemisphere summer and autumn; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere; slowly increasing water vapor values with altitude in the stratosphere, reaching 5-6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds.

Rind, D.; Chiou, E.-W.; Chu, W.; Oltmans, S.; Lerner, J.; Larsen, J.; Mccormick, M. P.; Mcmaster, L.

1993-01-01

14

Stratospheric water vapor feedback  

PubMed Central

We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry–climate model to be +0.3 W/(m2?K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-01-01

15

An experiment for measuring the low temperature vapor line of water  

NASA Astrophysics Data System (ADS)

A simple and low cost, but accurate, method to measure the vapor pressure curve of water below the normal boiling temperature is described. The apparatus uses the expansion power of hot air and steam. The vapor pressure is calculated by applying the ideal gas law, some elementary hydrostatics, and taking into account the water expansivity.

Velasco, S.; Faro, J.; Román, F. L.

2000-12-01

16

17Oexcess in evaporated desert waters and vapor from evaporation experiments  

NASA Astrophysics Data System (ADS)

Oxygen and hydrogen isotopes are classical proxies for the investigation of climatic effects in hydrological processes. The combination of the isotopic ratios 17O/16O and 18O/16O in water allowed the determination of mass dependent processes and enabled differentiation between equilibrium and kinetic fractionation (Barkan and Luz, 2007). In analogy to d-excess, deviation in ?17O from the global average trend of meteoric water is defined as: 17Oexcess = ?'17O - 0.528 × ?'18O 17Oexcess depends on the impact of diffusive evaporation into air and thus reflects relative humidity conditions. The isotope ratios of water ?17O and ?18O were determined by isotope ratio gas mass spectrometry in dual inlet mode on a ThermoFinnigan MAT 253. The oxygen was extracted by water fluorination with CoF3. Our average measurement precision for ?17O is ×0.03 ‰, for ?18O ×0.05 ‰ and for 17Oexcess approximately ×7 per meg (1?). We compared 17Oexcess in natural waters from the highly arid deserts of Sistan (East Iran) and Atacama (Chile) with data obtained from evaporation experiments. In these experiments, water was evaporated into a stream of dry nitrogen and vapor collected cryogenically. The data show a systematic depletion of 17Oexcess in water with increasing degree of evaporation in the residual water body. Most negative 17Oexcess were determined for samples from ponds (Sistan) and salars (Atacama). These strongly evaporated samples indicate an evaporation development, following a fractionation trend (?) of approximately 0.523. The evaporation experiment shows a ? of 0.525 and is in agreement with water data from an experiment by Barkan and Luz (2007). The difference between natural and experimental evaporation suggests either different evaporation kinetics in the natural environment, variable proportion of kinetic and equilibrium fractionation, or additional diffusive processes during ground water seepage. References: Barkan, E. and Luz, L. (2007). Diffusivity fractionations of H216O/H217O and H216O/H218O in air and their implications for isotope hydrology. Rapid Commun. Mass Spectrom., Vol. 21, pp. 2999-3005.

Surma, J.; Assonov, S.; Staubwasser, M.

2013-12-01

17

A comparison of the Stratospheric Aerosol and Gas Experiment II tropospheric water vapor to radiosonde measurements  

NASA Technical Reports Server (NTRS)

Results are presented of a comparison beteen observations of the upper-tropospheric water vapor data obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) instrument and radiosonde observations for 1987 and radiosonde-based climatologies. Colocated SAGE II-radiosonde measurement pairs are compared individually and in a zonal mean sense. A straight comparison of monthly zonal means between SAGE II and radiosondes for 1987 and Global Atmospheric Statistics (1963-1973) indicates that the clear-sky SAGE II climatology is approximately half the level of clear/cloudy sky of both radiosonde climatologies. Annual zonal means calculated from the set of profile pairs again showed SAGE II to be significantly drier in many altitude bands.

Larsen, J. C.; Chiou, E. W.; Chu, W. P.; Mccormick, M. P.; Mcmaster, L. R.; Oltmans, S.; Rind, D.

1993-01-01

18

Overview of the Stratospheric Aerosol and Gas Experiment II water vapor observations: Method, validation, and data characteristics  

SciTech Connect

Water vapor observations obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) solar occulation instrument for the troposphere and stratosphere are presented and compared with correlative in situ measurement techniques and other satellite data. The SAGE II instrument produces water vapor values from cloud top to approximately 1 mbar, except in regions of high aerosol content such as occurs in the low to middle stratosphere after volcanic eruptions. Details of the analysis procedure, instrumental errors, and data characteristics are discussed. Various features of the data set for the first 5 years after launch (1985-1989) are identified. These include an increase in middle and upper tropospheric water vapor during northern hemisphere summer and autumn, thus at times of warmest sea surface temperature; minimum water vapor values of 2.5-3 ppmv in the tropical lower stratosphere, with lower values during northern hemisphere winter and spring; slowly increasing water vapor values with altitude in the stratosphere, reaching 5-6 ppmv or greater near the stratopause; extratropical values with minimum profile amounts occurring above the conventionally defined tropopause; and higher extratropical than tropical water vapor values throughout the stratosphere except in locations of possible polar stratospheric clouds. SAGE II data will be useful for studying individual water vapor profiles, tropospheric response to climate perturbations, tropospheric-stratospheric exchange (due to its inherent high vertical resolution), and stratospheric transports. It should also aid in the preparation, for the first time on a global scale, of climatologies of the stratosphere and the upper level cloud-free troposphere, for use in radiative, dynamical, and chemical studies. 57 refs., 6 figs., 5 tabs.

Rind, D. (NASA/Goddard Inst. for Space Studies, New York, NY (United States)); Chiou, E.W.; Larsen, J. (STX Corp., Hampton, VA (United States)); Chu, W.; McCormick, M.P.; McMaster, L. (NASA/Langley Research Center, Hampton, VA (United States)); Oltmans, S. (NOAA/Climate Modeling and Diagnostic Lab., Boulder, CO (United States)); Lerner, J. (STX Corp., New York, NY (United States))

1993-03-20

19

Nucleation and growth rates of homogeneously condensing water vapor in argon from shock tube experiments  

Microsoft Academic Search

A special shock tube process combining a reflected expansion wave with a weak shock wave is analyzed and calibrated. The process is employed to transfer water vapor carried in argon into a known supersaturated state for a short period of time (0.5 ms). During that period steady state homogeneous nucleation takes place followed by condensational growth. Nucleation and growth rates

F. Peters; B. Paikert

1989-01-01

20

Intercomparison of stratospheric water vapor observed by satellite experiments - Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy  

NASA Technical Reports Server (NTRS)

A comparison is made of the stratospheric water vapor measurements made by the satellite sensors of the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus-7 LIMS, and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. It was found that, despite differences in the measurement techniques, sampling bias, and observational periods, the three experiments have disclosed a generally consistent pattern of stratospheric water vapor distribution. The only significant difference occurs at high southern altitudes in May below 18 km, where LIMS measurements were 2-3 ppmv greater than those of SAGE II and ATMOS.

Chiou, E. W.; Mccormick, M. P.; Mcmaster, L. R.; Chu, W. P.; Larsen, J. C.; Rind, D.; Oltmans, S.

1993-01-01

21

Stratospheric water vapor results from the limb infrared monitor of the stratosphere /LIMS/ experiment on Nimbus 7  

NASA Technical Reports Server (NTRS)

Stratospheric water vapor results taken from the limb infrared monitor of the stratosphere experiment on Nimbus 7 are presented with emphasis on validation studies. Basic radiance data, the indicated orbital precision of the experiment and comparisons made with data collected in simultaneous balloon underflights are described. A plot of pressure versus H2O channel radiance shows the radiance variability as a function of pressure and latitude. Measured precision is in good agreement with calculated values using simulations.

Russell, J. M., III; Remsberg, E. E.; Gordley, L. L.; Gille, J. C.; Bailey, P.

1981-01-01

22

Stratospheric water vapor results from the limb infrared monitor of the stratosphere /LIMS/ experiment on Nimbus 7  

NASA Astrophysics Data System (ADS)

Stratospheric water vapor results taken from the limb infrared monitor of the stratosphere experiment on Nimbus 7 are presented with emphasis on validation studies. Basic radiance data, the indicated orbital precision of the experiment and comparisons made with data collected in simultaneous balloon underflights are described. A plot of pressure versus H2O channel radiance shows the radiance variability as a function of pressure and latitude. Measured precision is in good agreement with calculated values using simulations.

Russell, J. M., III; Remsberg, E. E.; Gordley, L. L.; Gille, J. C.; Bailey, P.

23

Vapor Compression Distillation Flight Experiment  

NASA Technical Reports Server (NTRS)

One of the major requirements associated with operating the International Space Station is the transportation -- space shuttle and Russian Progress spacecraft launches - necessary to re-supply station crews with food and water. The Vapor Compression Distillation (VCD) Flight Experiment, managed by NASA's Marshall Space Flight Center in Huntsville, Ala., is a full-scale demonstration of technology being developed to recycle crewmember urine and wastewater aboard the International Space Station and thereby reduce the amount of water that must be re-supplied. Based on results of the VCD Flight Experiment, an operational urine processor will be installed in Node 3 of the space station in 2005.

Hutchens, Cindy F.

2002-01-01

24

ELF and ALEX SURF WINTER WAVES: Lidar Intercomparison of Aerosol and Water Vapor Measurements in the Baltimore-Washington Metropolitan Area During the Winter Water Vapor Validation Experiments (WAVES) 2008 campaign.  

NASA Astrophysics Data System (ADS)

Elastic and Raman lidar measurements were conducted to measure the vertical distribution of aerosols and water vapor during the Water Vapor Validation Experiments (WAVES) 2008 campaign by the University of Maryland Baltimore County (UMBC) Atmospheric Lidar Group at UMBC, at the same time as measurements at Howard University's Beltsville Research Station (26.5 km distant). The lidar profiles of atmospheric water vapor and aerosols allowed comparison for AURA/Aqua retrieval studies, by performing instrument accuracy assessments and data, generated by various independent active and passive remote sensing instruments for case studies of regional water vapor and aerosol sub-pixel variability. Integration of the lidar water vapor mixing ratios has been carried out to generate a column precipitable water vapor timeseries that can be compared to UMBC's SUOMINET station and Baltimore Bomem Atmospheric Emitted Radiance Interferometer (BBAERI). Changes in atmospheric aerosol concentration and water vapor mixing ratios due to meteorological events observed in the lidar timeseries have been correlated to the vertical temperature timeseries of BBAERI and to modeling of the air mass over the Baltimore-Washington metro area with the Weather Research and Forecasting (WRF) model.

Delgado, R.; Weldegaber, M.; Wilson, R. C.; McMillan, W.; McCann, K. J.; Woodman, M.; Demoz, B.; Adam, M.; Connell, R.; Venable, D.; Joseph, E.; Rabenhorst, S.; Twigg, L.; McGee, T.; Whiteman, D. N.; Hoff, R. M.

2008-12-01

25

Annual variations of water vapor in the stratosphere and upper troposphere observed by the Stratospheric Aerosol and Gas Experiment II  

SciTech Connect

This paper presents a description of the annual variations of water vapor in the stratosphere and the upper troposphere derived from observations of the Stratospheric Aerosol and Gas Experiment II (SAGE II). The altitude-time cross sections exhibit annually repeatable patterns in both hemispheres. The appearance of a yearly minimum in water vapor in both hemispheres at approximately the same time supports the idea of a common source(s) for stratospheric dry air. Annual patterns observed at northern mid-latitudes, like the appearance of a hygropause in winter and the weakening and upward shifting of the hygropause from January to May, agree with in situ balloon observations previously obtained over Boulder and Washington, DC. An increase in water vapor with altitude in the tropics is consistent with methane oxidation in the upper stratosphere to lower mesosphere as a source for water vapor. A poleward gradient is also shown as expected based on a Lagrangian mean circulation. A linear regression analysis using SAGE II data from January 1986 to December 1988 shows that little annual variation occurs in the middle and upper stratosphere with the region of large annual variability near the tropopause. The semi-annual variability is relatively marked at altitudes of 24 and 40 km in the tropics. 30 refs., 4 figs., 1 tab.

McCormick, M.P.; McMaster, L.R.; Chu, W.P. (NASA Langley Research Center, Hampton, VA (United States)); Chiou, E.W.; Larsen, J.C. (Hughes STX Corp., Hampton, VA (United States)); Rind, D. (NASA Goddard Inst. for Space Studies, New York, NY (United States)); Oltmans, S. (NOAA Climate Monitoring and Diagnostic Lab., Boulder, CO (United States))

1993-03-20

26

Relationships between polar mesospheric clouds, temperature, and water vapor from Solar Occultation for Ice Experiment (SOFIE) observations  

NASA Astrophysics Data System (ADS)

The goal of this work is to explore relationships between polar mesospheric clouds (PMCs), temperature, and water vapor and to understand the extent that bulk thermodynamic equilibrium can explain observed PMC characteristics. We use observations from the Solar Occultation for Ice Experiment (SOFIE) and employ a simple PMC model which assumes that ice exists in thermodynamic equilibrium with the local temperature and water vapor. Model results using SOFIE temperatures and water vapor are found to reproduce the observed ice layer altitudes, ice frequency versus time and altitude, ice mass density (expressed as the gas phase equivalent contained in the ice phase, Qice) versus time and altitude, and the vertical column abundance of ice (or ice water content (IWC)). The differences (model - SOFIE) for July 2008 were -0.1 km in the altitude of peak ice mass density (Zmax), 16% in Qice at Zmax, and 35% in IWC. These results suggest that on average, PMCs can exist in equilibrium with the surrounding environment, and the results also imply that ice nucleation may occur throughout the PMC altitude range. Good correlations were found between ice abundance and temperature (or saturation ratio), although knowledge of both water vapor and temperature is required for a quantitative prediction of observed ice characteristics. Our results indicate that the seasonal dependence of ice abundance is generally controlled by temperature and that in a broad sense, changes in water vapor are a result of changes in ice. We also find that lower temperatures are associated with higher ice mass density, higher ice concentration, and slightly smaller particle radii. This finding indicates that the increase in ice mass density is due to the nucleation of more particles rather than the growth of existing ice, and this finding points to nucleation as an important factor in determining PMC variability.

Hervig, Mark E.; Stevens, Michael H.; Gordley, Larry L.; Deaver, Lance E.; Russell, James M.; Bailey, Scott M.

2009-10-01

27

Water vapor lidar  

NASA Technical Reports Server (NTRS)

The feasibility was studied of measuring atmospheric water vapor by means of a tunable lidar operated from the space shuttle. The specific method evaluated was differential absorption, a two-color method in which the atmospheric path of interest is traversed by two laser pulses. Results are reported.

Ellingson, R.; Mcilrath, T.; Schwemmer, G.; Wilkerson, T. D.

1976-01-01

28

Water vapor diffusion membranes  

NASA Technical Reports Server (NTRS)

The program is reported, which was designed to define the membrane technology of the vapor diffusion water recovery process and to test this technology using commercially available or experimental membranes. One membrane was selected, on the basis of the defined technology, and was subjected to a 30-day demonstration trial.

Holland, F. F., Jr.; Smith, J. K.

1974-01-01

29

Analysis and forecast experiments incorporating satellite soundings and cloud and water vapor drift wind information  

NASA Technical Reports Server (NTRS)

A system for assimilating conventional meteorological data and satellite-derived data in order to produce four-dimensional gridded data sets of the primary atmospheric variables used for updating limited area forecast models is described. The basic principles of a data assimilation scheme as proposed by Lorenc (1984) are discussed. The design of the system and its incremental assimilation cycles are schematically presented. The assimilation system was tested using radiosonde, buoy, VAS temperature, dew point, gradient wind data, cloud drift, and water vapor motion data. The rms vector errors for the data are analyzed.

Goodman, Brian M.; Diak, George R.; Mills, Graham A.

1986-01-01

30

Quantification of the water vapor greenhouse effect: setup and first results of the Zugspitze radiative closure experiment  

NASA Astrophysics Data System (ADS)

Uncertainties in the knowledge of atmospheric radiative processes are among the main limiting factors for the accuracy of current climate models. Being the primary greenhouse gas in the Earth's atmosphere, water vapor is of crucial importance in atmospheric radiative transfer. However, water vapor absorption processes, especially the contribution attributed to the water vapor continuum, are currently not sufficiently well quantified. The aim of this study is therefore to obtain a more exact characterization of the water vapor radiative processes throughout the IR by means of a so-called radiative closure study at the Zugspitze/Schneefernerhaus observatory and thereby validate the radiative transfer codes used in current climate models. For that purpose, spectral radiance is measured at the Zugspitze summit observatory using an AERI-ER thermal emission radiometer (covering the far- and mid-infrared) and a solar absorption FTIR spectrometer (covering the near-infrared), respectively. These measurements are then compared to synthetic radiance spectra computed by means of the Line-By-Line Radiative Transfer Model (LBLRTM, Clough et al., 2005), a high resolution model widely used in the atmospheric science community. This line-by-line code provides the foundation of RRTM, a rapid radiation code (Mlawer et al., 1997) used in various weather forecast models or general circulation models like ECHAM. To be able to quantify errors in the description of water vapor radiative processes from spectral residuals, i.e. difference spectra between measured and calculated radiance, the atmospheric state used as an input to LBLRTM has to be constrained precisely. This input comprises water vapor columns, water vapor profiles, and temperature profiles measured by an LHATPRO microwave radiometer along with total column information on further trace gases (e.g. CO2 and O3) measured by the solar FTIR. We will present the setup of the Zugspitze radiative closure experiment. Due to its high-altitude location and the available permanent instrumentation, the Zugspitze observatory meets the necessary requirements to determine highly accurate water vapor continuum absorption parameters in the far- and mid-infrared spectral range from a more extensive set of closure measurements compared to previous campaign-based studies. Furthermore, we will present a novel radiometric calibration strategy for the solar FTIR spectral radiance measurements based on a combination of the Langley method and measurements of a high-temperature blackbody source that allows for the determination of continuum absorption parameters in the near-infrared spectral region, where previously no precise measurements under atmospheric conditions were available. This improved quantification of water vapor continuum absorption parameters allows us to further validate the current standard continuum model MT_CKD (Mlawer et al., 2012). Acknowledgements: Funding by KIT/IMK-IFU, the State Government of Bavaria as well as by the Deutsche Bundesstiftung Umwelt (DBU) is gratefully acknowledged. References: Clough, S. A., Shephard, M. W., Mlawer, E. J., Delamere, J. S., Iacono, M. J., Cady-Pereira, K., Boukabara, S., and Brown, P. D: Atmospheric radiative transfer modeling: a summary of the AER codes, Short Communication, J. Quant. Spectrosc. Radiat. Transfer, 91, 233-244, 2005. Mlawer, E. J., Taubman, J., Brown, P.D., Iacono, M.J, and Clough, S.A.: RRTM, a validated correlated-k model for the longwave. J. Geophys. Res., 102, 16,663-16,682, 1997. Mlawer, E. J., Payne V. H., Moncet, J., Delamere, J. S., Alvarado, M. J. and Tobin, D.C.: Development and recent evaluation of the MT_CKD model of continuum absorption, Phil. Trans. R. Soc. A, 370, 2520-2556, 2012.

Reichert, Andreas; Sussmann, Ralf; Rettinger, Markus

2014-05-01

31

Water Vapor Circulation on Earth  

NSDL National Science Digital Library

Water vapor plays an important role in the water cycle and in the distribution of heat around the planet. By observing the movement of water vapor, scientists can study global wind patterns and the development of cyclonic storms. This simulation from the National Center for Atmospheric Research shows the circulation of water vapor around the Earth over the course of a year. The segment is four minutes fifty-two seconds in length. Quicktime is required to view the clip.

2010-08-27

32

Intercomparison of stratospheric water vapor observed by satellite experiments: Stratospheric Aerosol and Gas Experiment II versus Limb Infrared Monitor of the Stratosphere and Atmospheric Trace Molecule Spectroscopy  

SciTech Connect

This paper presents a comparison of the stratospheric water vapor measurements made by the satellite-borne sensors the Stratospheric Aerosol and Gas Experiment II (SAGE II), the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS), and the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment. LIMS obtained data for 7 months between November 1978 and May 1979; ATMOS was carried on Shuttle and observed eight profiles from April 30 to May 6, 1985 at approximately 30[degrees]N and 50[degrees]S; and, SAGE II continues to make measurements since its launch in October 1984. For both 30[degrees]N and 50[degrees]S in May, the comparisons between SAGE II and ATMOS show agreement within the estimated combined uncertainty of the two experiments. Several important features identified by LIMS observations have been confirmed by SAGE II: a well-developed hygropause in the lower stratosphere at low- to mid-latitudes, a poleward latitudinal gradient, increasing water vapor mixing ratios with altitude in the tropics, and the transport of dry lower stratospheric water vapor upward and southward in May, and upward and northward in November. A detailed comparative study also indicates that the two previously suggested corrections for LIMS, a correction in tropical lower stratosphere due to a positive temperature bias and the correction above 28 km based on improved emissivities will bring LIMS measurements much closer to those of SAGE II. The only significant difference occurs at high southern latitudes in May below 18 km, where LIMS measurements are 2-3 ppmv greater. It should be noted that LIMS observations are from 16 to 50 km, ATMOS from 14 to 86 km, and SAGE II from mid-troposphere to 40 km. With multiyear coverage, SAGE II observations should be useful for studying tropospheric-stratospheric exchange, for stratospheric transport, and for preparing water vapor climatologies for the stratosphere and the upper troposphere. 32 refs., 14 figs., 2 tabs.

Chiou, E.W.; Larsen, J.C. (Hughes STX Corp., Hampton, VA (United States)); McCormick, M.P.; McMaster, L.R.; Chu, W.P. (NASA Langley Research Center, Hampton, VA (United States)); Rind, D. (NASA Goddard Inst. for Space Studies, New York, NY (United States)); Oltmans, S. (NOAA Climate Monitoring and Diagnostic Lab., Boulder, CO (United States))

1993-03-20

33

GEWEX Water Vapor Project (GVaP)  

NASA Technical Reports Server (NTRS)

The goal of the Global Energy and Water Cycle Experiment (GEWEX) Water Vapor Project (GVaP) is to improve the understanding of water vapor in meteorological, hydrological, and climatological processes through improving knowledge of water vapor and its variability on all scales. This goal clearly requires a multiscale observing strategy. A pilot project was deemed the most appropriate first step toward achieving this goal. An implementation plan was developed for this pilot phase. The four research components of the pilot phase are presented here.

Starr, David

1993-01-01

34

An evaluation of water vapor radiometer data for calibration of the wet path delay in very long baseline interferometry experiments  

NASA Technical Reports Server (NTRS)

The internal consistency of the baseline-length measurements derived from analysis of several independent VLBI experiments is an estimate of the measurement precision. The paper investigates whether the inclusion of water vapor radiometer (WVR) data as an absolute calibration of the propagation delay due to water vapor improves the precision of VLBI baseline-length measurements. The paper analyzes 28 International Radio Interferometric Surveying runs between June 1988 and January 1989; WVR measurements were made during each session. The addition of WVR data decreased the scatter of the length measurements of the baselines by 5-10 percent. The observed reduction in the scatter of the baseline lengths is less than what is expected from the behavior of the formal errors, which suggest that the baseline-length measurement precision should improve 10-20 percent if WVR data are included in the analysis. The discrepancy between the formal errors and the baseline-length results can be explained as the consequence of systematic errors in the dry-mapping function parameters, instrumental biases in the WVR and the barometer, or both.

Kuehn, C. E.; Himwich, W. E.; Clark, T. A.; Ma, C.

1991-01-01

35

A Physical Experiment to determine the Impact of Atmospheric Condensation of Water Vapor on Surface Air Movement  

NASA Astrophysics Data System (ADS)

A physical experiment, in which atmospheric air is enclosed in two interconnecting 4.8-metre high insulated PVC columns, consistently gives results showing that the condensation of water vapor, precipitated by means of refrigeration coils, gives rise to detectable air movements, with air speeds of up to 0.1 m/s. Once the compressor, sited well away from the two columns, is shut down, heavy drops of precipitated water are obtained which funnel into a flask for collection and measurement. The results in kg.m-2 (mm) from the 20 m3 volume of enclosed air accord well (>90%) with the physical calculations based on water vapor as an ideal gas. Air flow, resulting from the highly localized condensation, is measured through the movement of light-weight gauzes and an anemometer. It has a circulation time of some two minutes, such that both columns show cooling and a significant reduction in specific humidity from 0.01 to 0.005 (kg water vapor to kg dry air, r) with a drop in relative humidity of up to 40 per cent. Air flow is minimal during the control, non-refrigeration period of the experiment but becomes substantial within a minute of the compressor being switched on. The negative partial pressure change peaks at as much as 0.4 Pa/s during the first 30 minutes but reduces to approx. 0.08 Pa/s during the latter part of the 110 minute- long experiment. Airflow displays an inverse relationship to the partial pressure change, initially rising rapidly and then reducing before returning to zero once refrigeration has been switched off. Inverse correlations of up to 0.8 or higher between the partial pressure reduction and the airflow are obtained routinely. Semi-aquatic vegetation from the nearby marshland enhances precipitation, suggesting that evapotranspiration adds significantly to humidity. Without vegetation the condensation rate is 0.06 to 0.07 millimol.m-3.s-1 on average compared with 0.11 when vegetation is present. Cooling, by some 2°C, combined with a reduction in water vapor, by 6 grams/m3during the course of the experiment, leads to differential increases in air density. The latent heat released during condensation tends to warm the air in the immediate vicinity of the coolant coils and as such would tend to counter the air clockwise air-circulation, the assumption being that the highly localized partial pressure reduction on condensation is the overriding force. The experimental data accords well with data from Costa Rica, where, for the past three years, daily meteorological data have been collected from two OTS sites, namely La Selva and Palo Verde, the former in particular displaying relatively high rates of evapotranspiration. Statistically high correlations are found between the calculated evaporative/condensation force fE, and corresponding surface wind movements. Those findings, combined with the experimental data, suggest that a high rate of condensation and the consequent partial pressure reduction at the scale of the lower trophosphere leads to horizontal surface airflows of the order of 1 m.s-1.

Bunyard, P. P.; Nechev, P.

2013-12-01

36

Water vapor, whence comest thou.  

NASA Technical Reports Server (NTRS)

During a 14-hour period on Mar. 7, 1971, the Apollo 14 ALSEP suprathermal ion detector experiment (SIDE) observed an intense, prolonged series of bursts of 48.6-eV ions at the lunar surface. The SIDE mass analyzer showed the mass per unit charge of these ions to be characteristic of water vapor if singly ionized. The event was also observed by the SIDE total ion detectors (TIDs) at the Apollo 14 site and at Apollo 12 (located 183 km to the west). The TID data from SIDE 14 indicate that the energy spectrum was narrower than the 20-eV interval between energy channels. Ion spectra due to the LM exhaust gases are shown to be readily identified by the SIDE and are distinctly different in character from the spectra obtained on March 7. Detailed consideration of other possible sources of water, including the Apollo 14 CSM, leads to the conclusion that the water vapor did not come from a man-made source. Also, it is estimated that the event may have involved a quantity of water much greater than that which has been artificially introduced into the lunar environment. Consequently, it appears to be of lunar origin.

Freeman, J. W., Jr.; Hills, H. K.; Vondrak, R. R.

1972-01-01

37

Advanced Raman water vapor lidar  

NASA Technical Reports Server (NTRS)

Water vapor and aerosols are important atmospheric constituents. Knowledge of the structure of water vapor is important in understanding convective development, atmospheric stability, the interaction of the atmosphere with the surface, and energy feedback mechanisms and how they relate to global warming calculations. The Raman Lidar group at the NASA Goddard Space Flight Center (GSFC) developed an advanced Raman Lidar for use in measuring water vapor and aerosols in the earth's atmosphere. Drawing on the experience gained through the development and use of our previous Nd:YAG based system, we have developed a completely new lidar system which uses a XeF excimer laser and a large scanning mirror. The additional power of the excimer and the considerably improved optical throughput of the system have resulted in approximately a factor of 25 improvement in system performance for nighttime measurements. Every component of the current system has new design concepts incorporated. The lidar system consists of two mobile trailers; the first (13m x 2.4m) houses the lidar instrument, the other (9.75m x 2.4m) is for system control, realtime data display, and analysis. The laser transmitter is a Lambda Physik LPX 240 iCC operating at 400 Hz with a XeF gas mixture (351 nm). The telescope is a .75m horizontally mounted Dall-Kirkham system which is bore sited with a .8m x 1.1m elliptical flat which has a full 180 degree scan capability - horizon to horizon within a plane perpendicular to the long axis of the trailer. The telescope and scan mirror assembly are mounted on a 3.65m x .9m optical table which deploys out the rear of the trailer through the use of a motor driven slide rail system. The Raman returns from water vapor (403 nm), nitrogen (383 nm) and oxygen (372 nm) are measured in addition to the direct Rayleigh/Mie backscatter (351). The signal from each of these is split at about a 5/95 ratio between two photomultiplier detectors. The 5 percent detector is used for measurements below about 4.0 km, while the 95 percent detector provides the information above this level.

Whiteman, David N.; Melfi, S. Harvey; Ferrare, Richard A.; Evans, Keith A.; Ramos-Izquierdo, Luis; Staley, O. Glenn; Disilvestre, Raymond W.; Gorin, Inna; Kirks, Kenneth R.; Mamakos, William A.

1992-01-01

38

Water Vapor Circulation on Earth  

NSDL National Science Digital Library

This simulation from the National Center for Atmospheric Research portrays annual patterns in water vapor and precipitation across the globe, illustrating general circulation patterns as well as seasonal and regional variation.

Foundation, Wgbh E.

2005-10-21

39

A stratospheric water vapor feedback  

NASA Astrophysics Data System (ADS)

Variations in stratospheric water vapor play a role in the evolution of our climate. We show here that variations in water vapor since 2004 can be traced to tropical tropopause layer (TTL) temperature perturbations from at least three processes: the quasi-biennial oscillation, the strength of the Brewer-Dobson circulation, and the temperature of the troposphere. The connection between stratospheric water vapor and the temperature of the troposphere implies the existence of a stratospheric water vapor feedback. We estimate the feedback in a chemistry-climate model to have a magnitude of +0.3 W/m2/K, which could be a significant contributor to the overall climate sensitivity. About two-thirds of the feedback comes from the extratropical stratosphere below ~16 km (the lowermost stratosphere), with the rest coming from the stratosphere above ~16 km (the overworld).

Dessler, A. E.; Schoeberl, M. R.; Wang, T.; Davis, S. M.; Rosenlof, K. H.

2013-12-01

40

A Laboratory Water Vapor Laser.  

National Technical Information Service (NTIS)

A water vapor laser has been constructed that will emit coherent radiation in the far infrared. Although most construction details are typical of gas lasers, the particularly long wavelengths involved require some innovative design features. After a brief...

R. N. Chandler R. K. Likuski

1969-01-01

41

Water vapor adsorption on goethite.  

PubMed

Goethite (?-FeOOH) is an important mineral contributing to processes of atmospheric and terrestrial importance. Their interactions with water vapor are particularly relevant in these contexts. In this work, molecular details of water vapor (0.0-19.0 Torr; 0-96% relative humidity at 25 °C) adsorption at surfaces of synthetic goethite nanoparticles reacted with and without HCl and NaCl were resolved using vibrational spectroscopy. This technique probed interactions between surface (hydr)oxo groups and liquid water-like films. Molecular dynamics showed that structures and orientations adopted by these waters are comparable to those adopted at the interface with liquid water. Particle surfaces reacted with HCl accumulated less water than acid-free surfaces due to disruptions in hydrogen bond networks by chemisorbed waters and chloride. Particles reacted with NaCl had lower loadings below ?10 Torr water vapor but greater loadings above this value than salt-free surfaces. Water adsorption reactions were here affected by competitive hydration of coexisting salt-free surface regions, adsorbed chloride and sodium, as well as precipitated NaCl. Collectively, the findings presented in this study add further insight into the initial mechanisms of thin water film formation at goethite surfaces subjected to variations in water vapor pressure that are relevant to natural systems. PMID:23721420

Song, Xiaowei; Boily, Jean-François

2013-07-01

42

Multi-Filter Rotating Shadowband Radiometer (MFRSR) retrievals of total column aerosol, water vapor, and ozone during the Arm Enhanced Shortwave Experiment (ARESE)  

SciTech Connect

The ARESE provided an opportunity to compare MFRSR retrievals of total column aerosol optical depth, total column water vapor, and total column ozone with independent measurements of the same quantities during this campaign in the fall of 1995. MFRSR ozone was compared to ozonesondes that reached altitudes of at least 30 km. MFRSR water vapor was compared to microwave radiometer water vapor on several clear days during the campaign. Aerosol was measured by the ARM MFRSR and the Penn State Reagan sun photometer at high time resolution on a few days of the experiment. Only total column measurements of these constituents were compared. These comparisons were part of an effort to validate MFRSR retrievals that date from 1992. The daily total column aerosol optical depth record since that year illustrates the archival data and the variability of aerosol seasonally and during the decay of the Mt. Pinatubo stratospheric aerosol layer.

Michalsky, J.J.; Min, Qilong; Harrison, L.C.

1996-12-31

43

Vapor-liquid and liquid-liquid equilibria of water, 2-methoxyethanol and cyclohexanone: Experiment and correlation  

Microsoft Academic Search

Vapor-liquid equilibria and liquid-liquid equilibria of a ternary mixture consisting of water, 2-methoxyethanol and cyclohexanone and in addition of all binary subsystems were studied experimentally at several temperatures. A ternary corrective term in the expression for the Gibbs free energy based on the NRTL model improves simultaneous representation of binary and ternary phase equilibria.

T. Hauschild; H. Knapp

1994-01-01

44

Water vapor and cloud water measurements over Darwin during the STEP 1987 tropical mission  

Microsoft Academic Search

Measurements of stratospheric and upper tropospheric cloud water plus water vapor (total water) and water vapor were made with two Lyman alpha hygrometers as part of the STEP tropical experiment. The insitu measurements were made in the Darwin, Australia, area in January and February of 1987 on an ER-2 aircraft. Average stratospheric water vapor at a potential temperature of 375

K. K. Kelly; M. H. Proffitt; K. R. Chan; M. Loewenstein; J. R. Podolske; S. E. Strahan; J. C. Wilson; D. Kley

1993-01-01

45

Evaluation of Terms in the Water Vapor Budget Using Airborne Dial and In Situ Measurements from the Southern Great Plans 1997 Experiment  

NASA Technical Reports Server (NTRS)

The Southern Great Plains (SGP97) field experiment was conducted in Oklahoma during June and July 1997 primarily to validate soil moisture retrieval algorithms using microwave radiometer measurements from aircraft as well as in situ surface measurements. One important objective of the SGP97 experiment plan was to examine the effect of soil moisture on the evolution of the atmospheric boundary layer (ABL) and clouds over the Southern Great Plains during the warm season. To support boundary layer studies during SGP97. the NASA Langley Research Center's Lidar Atmospheric Sensing Experiment (LASE) was flown on a NASA-P3 aircraft in conjunction with the Electronically Scanned Thinned Array Radiometer (ESTAR). The LASE instrument is an airborne, downward-looking differential absorption lidar (DIAL) system capable of measuring water vapor concentration as well as aerosol backscatter with high horizontal and vertical resolution in the ABL. Here, we will demonstrate how the LASE data can be used to determine water vapor statistics and most of the water vapor budget terms in the ABL. This information can then be related to spatial variations in soil moisture and the surface energy budget. The extensive surface and aircraft in situ measurements conducted during SGP97 provide information on the ABL that cannot be retrieved from the LASE data alone and also offer an excellent opportunity to validate the remote water vapor budget measurements with LASE.

Senff, Christoph J.; Davis, Kenneth J.; Lenschow, Donald H.; Browell, Edward V.; Ismail, Syed

1998-01-01

46

The seasonal and global behavior of water vapor in the Mars atmosphere - Complete global results of the Viking atmospheric water detector experiment  

NASA Astrophysics Data System (ADS)

A key question regarding the evolution of Mars is related to the behavior of its volatiles. The present investigation is concerned with the global and seasonal abundances of water vapor in the Mars atmosphere as mapped by the Viking Mars Atmospheric Water Detector (MAWD) instrument for almost 1-1/2 Martian years from June 1976 to April 1979. Attention is given to the implications of the observed variations for determining the relative importance of those processes which may be controlling the vapor cycle on a seasonal basis. The processes considered include buffering of the atmosphere water by a surface or subsurface reservior of ground ice, physically adsorbed water, or chemically bound water. Other processes are related to the supply of water from the residual or seasonal north polar ice cap, the redistribution of the vapor resulting from atmospheric circulation, and control of the vapor holding capacity of the atmosphere by the local atmospheric temperatures.

Jakosky, B. M.; Farmer, C. B.

1982-04-01

47

Water vapor diffusion membranes, 2  

NASA Technical Reports Server (NTRS)

Transport mechanisms were investigated for the three different types of water vapor diffusion membranes. Membranes representing porous wetting and porous nonwetting structures as well as dense diffusive membrane structures were investigated for water permeation rate as a function of: (1) temperature, (2) solids composition in solution, and (3) such hydrodynamic parameters as sweep gas flow rate, solution flow rate and cell geometry. These properties were measured using nitrogen sweep gas to collect the effluent. In addition, the chemical stability to chromic acid-stabilized urine was measured for several of each type of membrane. A technology based on the mechanism of vapor transport was developed, whereby the vapor diffusion rates and relative susceptibility of membranes to fouling and failure could be projected for long-term vapor recovery trials using natural chromic acid-stabilized urine.

Holland, F. F.; Klein, E.; Smith, J. K.; Eyer, C.

1976-01-01

48

Water Vapor Imagery: Water Vapor and Jet Streams  

NSDL National Science Digital Library

This is a self-paced, on-line tutorial where learners can identify and analyze jet streams using water vapor imagery from weather satellites. Learners are introduced to the concept and function of the water vapor channel and how these images compare with weather models. An optional embedded refresher tutorial with providing meteorological background information about jet streams supports student-centered investigations in three learning scenarios: a jet stream tracking challenge made by a TV meteorologist, analyzing data in a in-air turbulence scenario involving an airline pilot, and a decision-making challenge involving the launching and tracking of a weather balloon. This resource is part of the tutorial series, Satellite Observations in Science Education, and is the third of three modules in the tutorial, Water Vapor Imagery. (Note: requires Java plug-in)

49

The atmospheric water vapor line.  

NASA Astrophysics Data System (ADS)

We have measured the hydrogen and oxygen isotope composition of atmospheric water vapor periodically across the American Southwest through most of 2007. Samples were primarily collected over Albuquerque, NM on the roof of the 3-story UNM geology building on a near-daily basis with occasional sampling in southern Arizona and southern Texas. Water vapor was captured by pumping ~60 to ~600 liters of air (amount depending on dew point) through a cold trap, producing ~1mL of water. Precipitation samples were also collected in Albuquerque throughout the year and analyzed for hydrogen and oxygen isotopic composition. Isotopic compositions of both vapor and precipitation were determined by CO2 equilibration for oxygen and chromium reduction for hydrogen, with resulting gasses analyzed on a mass spectrometer. Nearly all water vapor samples lie parallel to the Global Meteoric Water Line (GMWL) but with a deuterium excess of ~17 (?D = 8?O + 17). This is true regardless of relative humidity, dew point, location, time of day, or season. Precipitation samples fall to the right of the GMWL with a slope of ~5. Within our dataset we have identified 10 pairs of vapor and precipitation samples that were collected within 24 hours. Half of these sample pairs have values consistent with equilibrium conditions at ground temperature, while the other half are not in equilibrium at any temperature. Simple modeling of nonequilibrium fractionation processes suggests that the array of precipitation samples can be derived from the array of vapor samples by equilibrium condensation followed by partial evaporation of falling raindrops. Our data suggests that atmospheric water vapor has a relatively constant deuterium excess value regardless of moisture source, degree of rainout, and/or evapotranspiration contributions.

Strong, M.; Sharp, Z. D.; Gutzler, D. S.

2008-12-01

50

Validation of water vapor results measured by the Limb Infrared Monitor of the Stratosphere experiment on Nimbus 7  

NASA Technical Reports Server (NTRS)

In the LIMS experiment using thermal IR limb scanning to sound the composition and structure of the upper atmosphere, one of the LIMS channels was spectrally centered at 6.9 micrometers to measure the vertical profile and global distribution of stratospheric water vapor. This channel's characteristics, the data from it, and the steps taken to validate results are described. The mean difference between the LIMS measurements and data from 13 balloon underflights is about 0.6 ppmv with LIMS mixing ratios biased high; this difference is of about the same order as estimated LIMS accuracy and less than the sum of the errors for LIMS and the balloon techniques. In-orbit precision is 0.2-0.3 ppmv and accuracy is estimated at 20-30 percent from 50 mbar to the stratopause. An unexplained diurnal variation exists in the vertical profile data which is largest at the 1-mbar level and virtually nonexistent at 10 mbar; day values are higher than night. More confidence is placed in zonal mean distributions averaged over several days than in single profiles. A zonal mean pressure-latitude cross section is described for January 5-9, 1979.

Russell, J. M., III; Remsberg, E. E.; Gille, J. C.; Bailey, P. L.; Gordley, L. L.; Fischer, H.; Girard, A.; Drayson, S. R.; Evans, W. F. J.; Harries, J. E.

1984-01-01

51

Forward Model Studies of Water Vapor Using Scanning Microwave Radiometers, Global Positioning System, and Radiosondes during the Cloudiness Intercomparison Experiment  

SciTech Connect

Brightness temperatures computed from five absorption models and radiosonde observations were analyzed by comparing them with measurements from three microwave radiometers at 23.8 and 31.4 GHz. Data were obtained during the Cloudiness Inter-Comparison experiment at the U.S. Department of Energy's Atmospheric Radiation Measurement Program's (ARM) site in North-Central Oklahoma in 2003. The radiometers were calibrated using two procedures, the so-called instantaneous ?tipcal? method and an automatic self-calibration algorithm. Measurements from the radiometers were in agreement, with less than a 0.4-K difference during clear skies, when the instantaneous method was applied. Brightness temperatures from the radiometer and the radiosonde showed an agreement of less than 0.55 K when the most recent absorption models were considered. Precipitable water vapor (PWV) computed from the radiometers were also compared to the PWV derived from a Global Positioning System station that operates at the ARM site. The instruments agree to within 0.1 cm in PWV retrieval.

Mattioli, Vinia; Westwater, Ed R.; Gutman, S.; Morris, Victor R.

2005-05-01

52

Terahertz Spectroscopy of Water Vapors, Chemical Vapors and Ionized Air  

NASA Astrophysics Data System (ADS)

In the past, a few research groups have demonstrated that terahertz spectroscopy could be a useful tool for the identification of chemicals. However most of those demonstrations have been done with solid-phase or liquid-phase chemicals. There are little demonstrations for the detection and identification of chemicals in the gas-phase, as it is very difficult in part due to the presence of water-absorption lines in the terahertz frequency range. As the water absorption lines predominate in the 0.1 - 2THz spectral range, and can interfere with already weak terahertz signatures generated by chemical vapors, it is often very hard to obtain meaningful terahertz spectrum of chemical vapor. Regardless we recently have been able to obtain some terahertz spectra of chemical vapors and ionized air produced by several different ionization sources, including corona discharge and nuclear isotopes. Throughout data analysis we learned that water molecules, nitrogen and oxygen molecules play very important roles in these terahertz spectra. In this presentation we will discuss our experiments and the roles of these molecules.

Graber, Benjamin; Tao, Rongjia; Wu, Dong Ho

2013-03-01

53

First UV satellite observations of mesospheric water vapor  

Microsoft Academic Search

We report the first UV satellite observations of mesospheric water vapor. The measurements are of nonthermal OH prompt emission between 300-330 nm produced directly from the photodissociation of water vapor by H Lyman-alpha. This technique is most sensitive to water vapor concentrations between 70-90 km altitude. We present OH data from two limb scanning experiments: the Middle Atmosphere High Resolution

Michael H. Stevens; R. L. Gattinger; J. Gumbel; E. J. Llewellyn; D. A. Degenstein; M. Khaplanov; G. Witt

2008-01-01

54

Water vapor in protoplanetary disks  

NASA Astrophysics Data System (ADS)

This thesis is devoted to a study of the conditions and evolution of the planet formation region in young circumstellar disks, by means of spectroscopic observations of molecular gas emission. The main focus of this work is the infrared spectrum of water (H2O), which provides thousands of emission lines tracing the warm and dense gas inward of the water snow line in disks. The analysis includes also emission from some organic molecules that trace the carbon chemistry, C2H2, HCN, and CO2, as well as emission from OH that is connected to the formation and destruction of the water molecule. Two are the main directions explored in this work, for which we used spectra from the Spitzer Space Telescope (IRS) and the Very Large Telescope (VISIR and X-shooter). The first is to investigate how variable accretion phenomena occurring during the T Tauri phase affect the molecular environments in the planet formation region of disks. By monitoring T Tauri stars in different phases of accretion, we found that outbursts can remarkably affect their mid-infrared molecular emission. We propose a scenario where accretion flares trigger a recession of the water snow line, increasing water emission from the disk, when the accretion luminosity keeps higher over long enough timescales for the thermal structure of the disk to change (at least a few weeks, as observed in the strongly variable EX Lupi). In addition, enhanced UV radiation is found to produce OH from photodissociation of water in the disk. Organic molecules instead disappear during a strong outburst, and we are currently investigating the long-term evolution of these effects. A second direction was taken to tackle another fundamental problem: the origin of water vapor in inner disks. Some models predict that water is produced by evaporation of icy solids migrating inward of the snow line. One way to probe this scenario is by measuring the abundance of water vapor in the inner disk, and compare it to the oxygen abundance available to form water in situ. In this thesis, for the first time, a systematic rotation diagram analysis has been applied to infrared water emission. This analysis established a link between the spread of the rotational scatter and the water abundance in the inner disk, where a large rotational scatter would provide evidence for the migration scenario. Large rotational scatters are indeed tentatively observed in some disks, supporting water vapor enrichment from evaporation of icy migrators. Future higher-resolution observations will provide important answers on the origin of water vapor and its connection to disk evolution and planet formation processes.

Banzatti, Andrea

2013-03-01

55

Water Vapor Permeability of Plastic Fast Packs.  

National Technical Information Service (NTIS)

The objective of this investigation was to perform nondestructive tests that quantitatively measured the water vapor permeability of a plastic (high density polyethylene) Type I Fast Pack design. The water vapor transmission rate (WVTR) of the new pack de...

J. A. Hincks

1978-01-01

56

Water vapor diffusion membrane development  

NASA Technical Reports Server (NTRS)

A total of 18 different membranes were procured, characterized, and tested in a modified bench-scale vapor diffusion water reclamation unit. Four membranes were selected for further studies involving membrane fouling. Emphasis was placed on the problem of flux decline due to membrane fouling. This is discussed in greater details under "Summary and Discussion on Membrane Fouling Studies" presented in pages 47-51. The system was also investigated for low temperature application on wash-water where the permeated water is not recovered but vented into space vacuum.

Tan, M. K.

1976-01-01

57

Internal Water Vapor Photoacoustic Calibration  

NASA Technical Reports Server (NTRS)

Water vapor absorption is ubiquitous in the infrared wavelength range where photoacoustic trace gas detectors operate. This technique allows for discontinuous wavelength tuning by temperature-jumping a laser diode from one range to another within a time span suitable for photoacoustic calibration. The use of an internal calibration eliminates the need for external calibrated reference gases. Commercial applications include an improvement of photoacoustic spectrometers in all fields of use.

Pilgrim, Jeffrey S.

2009-01-01

58

Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point  

ERIC Educational Resources Information Center

Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

Tellinghuisen, Joel

2010-01-01

59

Water Vapor Sorption of Package Sealants  

Microsoft Academic Search

A unique system, designed for simultaneously measuring mass change and residual gases of samples loaded from a controlled environment, was used in conducting outgassing and water vapor adsorption-desorption experiments on sealing glasses. Owens-Illinois XS-1175, a vitreous sealing glass, was glazed in vacuum, air, nitrogen and oxygen and Owens-Illinois CV-ll, a devitrifying sealing glass, was glazed in vacuum. The outgassing products

R. W. Vasofsky

1979-01-01

60

Water vapor diffusion membrane development  

NASA Technical Reports Server (NTRS)

An application of the water vapor diffusion technique is examined whereby the permeated water vapor is vented to space vacuum to alleviate on-board waste storage and provide supplemental cooling. The work reported herein deals primarily with the vapor diffusion-heat rejection (VD-HR) as it applies to the Space Shuttle. A stack configuration was selected, designed and fabricated. An asymmetric cellulose acetate membrane, used in reverse osmosis application was selected and a special spacer was designed to enhance mixing and promote mass transfer. A skid-mount unit was assembled from components used in the bench unit although no attempt was made to render it flight-suitable. The operating conditions of the VD-HR were examined and defined and a 60-day continuous test was carried out. The membranes performed very well throughout the test; no membrane rupture and no unusual flux decay was observed. In addition, a tentative design for a flight-suitable VD-HR unit was made.

Tan, M. K.

1977-01-01

61

Seasonal and global behavior of water vapor in the Mars atmosphere: Complete global results of the Viking atmospheric water detector experiment  

SciTech Connect

The water vapor content of the Mars atmosphere was measured from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) for a period of more than 1 Martian year, from June 1976 through April 1979. Results are presented in the form of global maps of column abundance for 24 periods throughout each Mars year. The data reduction incorporates spatial and seasonal variations in surface pressure and supplements earlier published versions of less complete data.

Jakosky, B.M.; Farmer, C.B.

1982-04-10

62

Airborne LIDAR Measurements of Water Vapor, Ozone, Clouds, and Aerosols in the Tropics Near Central America During the TC4 Experiment  

NASA Technical Reports Server (NTRS)

Large scale distributions of ozone, water vapor, aerosols, and clouds were measured throughout the troposphere by two NASA Langley lidar systems on board the NASA DC-8 aircraft as part of the Tropical Composition, Cloud, and Climate Coupling Experiment (TC4) over Central and South America and adjacent oceans in the summer of 2007. Special emphasis was placed on the sampling of convective outflow and transport, sub-visible cirrus clouds, boundary layer aerosols, Saharan dust, volcanic emissions, and urban and biomass burning plumes. This paper presents preliminary results from this campaign, and demonstrates the value of coordinated measurements by the two lidar systems.

Kooi, Susan; Fenn, Marta; Ismail, Syed; Ferrare, Richard; Hair, John; Browell, Edward; Notari, Anthony; Butler, Carolyn; Burton, Sharon; Simpson, Steven

2008-01-01

63

Multi-Filter Rotating Shadowband Radiometer (MFRSR) retrievals of total column aerosol, water vapor, and ozone during the Arm Enhanced Shortwave Experiment (ARESE)  

Microsoft Academic Search

The ARESE provided an opportunity to compare MFRSR retrievals of total column aerosol optical depth, total column water vapor, and total column ozone with independent measurements of the same quantities during this campaign in the fall of 1995. MFRSR ozone was compared to ozonesondes that reached altitudes of at least 30 km. MFRSR water vapor was compared to microwave radiometer

J. J. Michalsky; Qilong Min; L. C. Harrison

1996-01-01

64

Does Air Contain Water Vapor?  

NSDL National Science Digital Library

In this activity, students monitor the change that takes place when water vapor condenses from a gas to a liquid and see how a change in temperature affects this transformation. Materials needed to conduct the investigation include two thermometers, a clear glass container, ice cubes and tap water. The resource includes background information, teaching tips and questions to guide student discussion. This is chapter 10 of Meteorology: An Educator's Resource for Inquiry-Based Learning for Grades 5-9. The guide includes a discussion of learning science, the use of inquiry in the classroom, instructions for making simple weather instruments, and more than 20 weather investigations ranging from teacher-centered to guided and open inquiry investigations.

65

Cell for electrolysis of water vapor  

NASA Technical Reports Server (NTRS)

Electrolytic cells regenerate oxygen from the water vapor in the air of closed-loop life-support system and remove water vapor from air circulated through them. Water is converted into oxygen and hydrogen; the oxygen is returned to the air, the hydrogen is vented or used elsewhere.

Celino, V. A.; Roebelen, G.

1972-01-01

66

Water vapor trends over Boulder, Colorado  

NASA Astrophysics Data System (ADS)

Water vapor in the atmosphere is responsible for a significant portion of the greenhouse effect, and even small changes in the upper troposphere or lower stratosphere can have a large effect on climate. A new analysis of water vapor measurements by balloon-borne frost point hygrometers over Boulder, Colo., shows that stratospheric water vapor has increased over the past 30 years. Hurst et al. broke the long measurement record into four discrete time periods and determined the water vapor trends in each period for five 2-kilometer-thick stratospheric layers (16-26 kilometers in altitude). The scientists found that, on average, stratospheric water vapor increased by about 1 part per million by volume (27%) over the past 30 years, though there were many shorter-term variations in the record. Water vapor levels increased during 1980-1989 and 1990-2000, decreased from 2001 to 2005, and then increased again after 2005. The authors found that, at most, 30% of the observed water vapor increases can be attributed to greater amounts of methane oxidation in the stratosphere. The 2001-2005 decrease in midlatitude water vapor has been linked to observations of anomalously low tropopause temperatures in the tropics, but, to date, no connection between the observed water vapor increases and tropical tropopause temperatures has been found despite ongoing efforts. (Journal of Geophysical Research-Atmospheres, doi:10.1029/2010JD015065, 2011)

Tretkoff, Ernie

2011-04-01

67

Observe animated satellite images of water vapor  

NSDL National Science Digital Library

This Flash animation points out water vapor content 6-10 km above Earth's surface measured by infrared sensors on satellites. Lighter areas represent high moisture content, darker areas, little water vapor. Jet streams are viewed as elongated dark regions bordered by lighter sections.

Goes; Noaa; Earth, Exploring

68

Advanced Atmospheric Water Vapor DIAL Detection System.  

National Technical Information Service (NTIS)

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. Thi...

T. F. Refaat H. E. Elsayed-Ali

2000-01-01

69

Water vapor retrieval over many surface types  

SciTech Connect

In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

Borel, C.C.; Clodius, W.C.; Johnson, J.

1996-04-01

70

Interannual Changes of Stratospheric Water Vapor and Correlations with Tropical Tropopause Temperatures  

Microsoft Academic Search

Interannual variations of stratospheric water vapor over 1992-2003 are studied using Halogen Occultation Experiment (HALOE) satellite measurements. Interannual anomalies in water vapor with an approximate 2-yr periodicity are evident near the tropical tropopause, and these propagate vertically and latitudinally with the mean stratospheric transport circulation (in a manner analogous to the seasonal ''tape recorder''). Unusually low water vapor anomalies are

William J. Randel; Fei Wu; Samuel J. Oltmans; Karen Rosenlof; Gerald E. Nedoluha

2004-01-01

71

CO2 DIAL measurements of water vapor  

NASA Technical Reports Server (NTRS)

CO2 lidars have heretofore been used to measure water vapor concentrations primarily using the 10R(20) line at 10.247 microns, which has a strong overlap with a water vapor absorption line. This paper discusses the use of that line as well as other CO2 laser lines for which the absorption coefficients are weaker. The literature on measurement of water vapor absorption coefficients using CO2 lasers is reviewed, and the results from four laboratories are shown to be generally consistent with each other after they are normalized to the same partial pressure, temperature, and ethylene absorption coefficent for the 10P(14) CO2 laser line; however, the agreement with the Air Force Geophysics Laboratory's HITRAN and FASCOD 2 spectral data tapes is not good either for the water vapor absorption lines or for the water vapor continuum. Demonstration measurements of atmospheric water vapor have been conducted using the Mobile Atmospheric Pollutant Mapping System, a dual CO2 lidar system using heterodyne detection. Results are discussed for measurements using three sets of laser line pairs covering a wide range of water vapor partial pressures.

Grant, William B.; Margolis, Jack S.; Brothers, Alan M.; Tratt, David M.

1987-01-01

72

Remote sensing of water vapor features  

NASA Technical Reports Server (NTRS)

Water vapor plays a critical role in the atmosphere. It is an important medium of energy exchange between air, land, and water; it is a major greenhouse gas, providing a crucial radiative role in the global climate system; and it is intimately involved in many regional scale atmospheric processes. Our research has been aimed at improving satellite remote sensing of water vapor and better understanding its role in meteorological processes. Our early studies evaluated the current GOES VAS system for measuring water vapor and have used VAS-derived water vapor data to examine pre-thunderstorm environments. Much of that research was described at the 1991 Research Review. A second research component has considered three proposed sensors--the High resolution Interferometer Sounder (HIS), the Multispectral Atmospheric Mapping Sensor (MAMS), and the Advanced Microwave Sounding Unit (AMSU). We have focused on MAMS and AMSU research during the past year and the accomplishments made in this effort are presented.

Fuelberg, Henry E.

1993-01-01

73

Water vapor recovery from plant growth chambers  

NASA Technical Reports Server (NTRS)

NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. A design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: (1) dehumidification membrane modules to remove water vapor from the air, and (2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

Ray, R. J.; Newbold, D. D.; Colton, R. H.; Mccray, S. B.

1991-01-01

74

High Temperature Water Vapor Electrolysis (Hot Elly).  

National Technical Information Service (NTIS)

The practicability of high temperature water vapor electrolysis was demonstrated on a laboratory scale. The component raw materials selection is described, and the manufacture of high temperature electrolysis cells is delineated. Electrolytic operation of...

W. Doenitz H. Hermeking I. Kitzmann A. Koch R. Roettenbacher

1980-01-01

75

High Temperature Water Vapor Electrolysis (HOT ELLY).  

National Technical Information Service (NTIS)

The objective of the project HOT ELLY (phase 1) was the demonstration of the practicability of high temperature water vapor electrolysis on a laboratory scale. Starting from basic material studies the components (using sufficiently cheap raw materials) as...

W. Doenitz H. Hermeking I. Kitzmann A. Koch R. Roettenbacher

1980-01-01

76

Sorption of Water Vapors by Armos Fibre  

Microsoft Academic Search

The extremely slow kinetics of absorption of water vapors by Armos fibre can be explained by notions concerning its cross-linked structure, which consists of units of the crystallite type and liquid-crystalline or amorphous crosslinks and has a relatively high density. Sorption of water vapors by the initial Armos fibre not treated with heat is much higher than for the heat-treated

L. Ya. Konovalova; M. M. Iovleva; G. S. Negodyaeva; G. A. Budnitskii; N. N. Machalaba

2003-01-01

77

Optical monitor for water vapor concentration  

DOEpatents

A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma. 5 figs.

Kebabian, P.

1998-06-02

78

Optical monitor for water vapor concentration  

DOEpatents

A system for measuring and monitoring water vapor concentration in a sample uses as a light source an argon discharge lamp, which inherently emits light with a spectral line that is close to a water vapor absorption line. In a preferred embodiment, the argon line is split by a magnetic field parallel to the direction of light propagation from the lamp into sets of components of downshifted and upshifted frequencies of approximately 1575 Gauss. The downshifted components are centered on a water vapor absorption line and are thus readily absorbed by water vapor in the sample; the upshifted components are moved away from that absorption line and are minimally absorbed. A polarization modulator alternately selects the upshifted components or downshifted components and passes the selected components to the sample. After transmission through the sample, the transmitted intensity of a component of the argon line varies as a result of absorption by the water vapor. The system then determines the concentration of water vapor in the sample based on differences in the transmitted intensity between the two sets of components. In alternative embodiments alternate selection of sets of components is achieved by selectively reversing the polarity of the magnetic field or by selectively supplying the magnetic field to the emitting plasma.

Kebabian, Paul (Acton, MA)

1998-01-01

79

Vacuum distillation/vapor filtration water recovery  

NASA Technical Reports Server (NTRS)

The development and evaluation of a vacuum distillation/vapor filtration (VD/VF) water recovery system are considered. As a functional model, the system converts urine and condensates waste water from six men to potable water on a steady-state basis. The system is designed for 180-day operating durations and for function on the ground, on zero-g aircraft, and in orbit. Preparatory tasks are summarized for conducting low gravity tests of a vacuum distillation/vapor filtration system for recovering water from urine.

Honegger, R. J.; Neveril, R. B.; Remus, G. A.

1974-01-01

80

The Apollo lunar surface water vapor event revisited  

NASA Astrophysics Data System (ADS)

On March 7, 1971, the first sunrise following the Apollo 14 mission, the Suprathermal Ion Detector Experiment (SIDE) deployed at the Apollo 14 site reported an intense flux of ions whose mass per charge was consistent with water vapor. The amount of water is examined, and the various acceleration processes, responsible for accelerating ions into the SIDE, are discussed. It is concluded that during most of the event the observed water vapor ions were accelerated by the negative lunar surface electric potential and, secondly, that this event was probably the result of mission associated water vapor, either from the LM ascent and descent stage rockets or from residual water in the descent stage tanks.

Freeman, J. W., Jr.; Hills, H. K.

1991-11-01

81

Characterization of upper troposphere water vapor measurements during AFWEX using LASE.  

SciTech Connect

Water vapor profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the ARM/FIRE Water Vapor Experiment (AFWEX) are used to characterize upper troposphere (UT) water vapor measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. Initial comparisons showed the average Vaisala radiosonde measurements to be 5-15% drier than the average LASE, Raman lidar, and DC-8 in situ diode laser hygrometer measurements. They show that corrections to the Raman lidar and Vaisala measurements significantly reduce these differences. Precipitable water vapor (PWV) derived from the LASE water vapor profiles agrees within 3% on average with PWV derived from the ARM ground-based microwave radiometer (MWR). The agreement among the LASE, Raman lidar, and MWR measurements demonstrates how the LASE measurements can be used to characterize both profile and column water vapor measurements and that ARM Raman lidar, when calibrated using the MWR PWV, can provide accurate UT water vapor measurements.

Ferrare, R. A.; Browell, E. V.; Ismail, I.; Kooi, S.; Brasseur, L. H.; Brackett, V. G.; Clayton, M.; Barrick, J.; Bosenberg, J.; Diskin, G.; Goldsmith, J.; Lesht, B.; Podolske, J.; Sachse, G.; Schmidlin, F. J.; Turner, D.; Whitemann, D.

2002-07-15

82

Use of the Selected Overlap Lidar Experiment (SOLEX) system with the 248 nm KrF laser for the calibration of a Lidar System for water vapor determination  

NASA Astrophysics Data System (ADS)

Water vapor is one of the most important atmospheric variables that play a key role in air quality, global warming, and climate change. However, it remains one of the most poorly characterized meteorological parameters. For example, water vapor measurements have proven to be difficult below 300 m in the lower troposphere. Despite its abundance in the atmosphere, and its importance for the climate system, many questions regarding water vapor are presently unresolved. Because of its particular importance in tropospheric processes and the extraordinary ability of Raman Lidar through the SOLEX system^ to sense accurately its high temporal and spatial structure in the atmosphere, we present here some particular details about the use of Raman Lidar SOLEX system to measure water vapor at lower atmosphere at several fixed ranges such as 440 ft, 525 ft, 680 ft, 800 ft, and 1000 ft. A comparison is made between data obtained from the laser system and the ones obtained from calibrated temperature and relative humidity's sensors at the same location.

Mensah, Francis; Thorpe, Arthur

2010-03-01

83

Observed dependence of the water vapor and clear-sky greenhouse effect on sea surface temperature: Comparison with climate warming experiments  

Microsoft Academic Search

This study presents a comparison of the water vapor and clear-sky greenhouse effect dependence on sea surface temperature for climate variations of different types. Firstly, coincident satellite observations and meteorological analyses are used to examine seasonal and interannual variations and to evaluate the performance of a general circulation model. Then, this model is used to compare the results inferred from

Sandrine Bony; H. Le Treut; J. P. Duvel

1995-01-01

84

Observed dependence of the water vapor and clear-sky greenhouse effect on sea surface temperature: comparison with climate warming experiments  

Microsoft Academic Search

This study presents a comparison of the water vapor and clear-sky greenhouse effect dependence on sea surface temperature for climate variations of different types. Firstly, coincident satellite observations and meteorological analyses are used to examine seasonal and interannual variations and to evaluate the performance of a general circulation model. Then, this model is used to compare the results inferred from

Sandrine Bony; Jean-Philippe Duvel; Hervé Trent

1995-01-01

85

Refraction of microwave signals by water vapor  

NASA Technical Reports Server (NTRS)

Tropospheric water vapor causes a refractive path length effect which is typically 5-10% of the 'dry' tropospheric effect and as large as several meters at elevation angles below 5 deg. The vertical water vapor profile is quite variable, and measurements of intensive atmospheric parameters such as temperature and humidity limited to the surface do not adequately predict the refractive effect. It is suggested that a water vapor refraction model that is a function of the amount of precipitable water alone can be successful at low elevation angles. From an extensive study of numerical ray tracings through radiosonde balloon data, such a model has been constructed. The model predicts the effect at all latitudes and elevation angles between 2 and 10 deg to an accuracy of better than 4% (11 cm at 3 deg elevation angle).

Goldfinger, A. D.

1980-01-01

86

Advanced Atmospheric Water Vapor DIAL Detection System  

NASA Technical Reports Server (NTRS)

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface. This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto a small Printed Circuit Board (PCB) with minimal weight and power consumption. Comparing its measurements to an existing DIAL system for aerosol and water vapor profiling validated the detection system.

Refaat, Tamer F.; Elsayed-Ali, Hani E.; DeYoung, Russell J. (Technical Monitor)

2000-01-01

87

Measurements of water vapor in Mars' antarctic  

NASA Technical Reports Server (NTRS)

A complete Mars year of measurements of atmospheric water vapor in the south arctic have been obtained from the Viking Orbiters. Analysis of the observations indicates that, except for the south remnant cap, the southern hemisphere of Mars is devoid of any substantial reservoirs of water in contact with the atmosphere, and that, in the summer time, the top layer of soil is desiccated. Small amounts of water ice are incorporated into the annual CO2 cap; this water is released at the cap margin when it retreats in the spring. The first global dust storm resulted in heating of the south arctic atmosphere and a transport of water in from the equatorial region. The second global dust storm had a negligible effect on atmospheric water vapor; the dust contained little water.

Davies, D. W.; Wainio, L. A.

1981-01-01

88

High temperature measurement of water vapor absorption  

NASA Technical Reports Server (NTRS)

An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

1985-01-01

89

Raman Lidar Water Vapor Measurements at the DOE SGP CART Site  

NASA Technical Reports Server (NTRS)

The NASA/GSFC Scanning Raman Lidar (SRL) was deployed to the Department of Energy's (DOE) Cloud and Radiation Testbed site in northern Oklahoma September - December, 2000 for two DOE sponsored field campaigns: 1) the Water Vapor Intensive Operations Experiment 2000 and 2) the Atmospheric Radiations Measurement First International Satellite Cloud Climatology Experiment Experiment (AFWEX). WvIOP2000 focussed on water vapor measurements in the lower troposphere while AFWEX focussed on upper tropospheric water vapor. For the first time ever, four water vapor lidars were operated simultaneously: one airborne and three ground-based systems. Intercomparisons of these measurements and others will be presented at the meeting.

Whiteman, David N.; Smith, David E. (Technical Monitor)

2001-01-01

90

Possible seasonal variability of mesospheric water vapor  

NASA Technical Reports Server (NTRS)

Ground-based spectral line measurements of the 22.2 GHz water vapor line in atmospheric emission were made at the Jet Propulsion Laboratory, which have been used to deduce the mesospheric water vapor profile. The measurements were made nearly continuously in the spring and early summer of 1984. The results indicate a temporal increase in the water vapor mixing ratio in the upper mesosphere from April through June. At 75 km, this increase is nearly by a factor of 2. Comparison of the present results with the results of a similar series of measurements made at the Haystack (radio astronomy) Observatory indicate that this temporal increase is part of a seasonal variation.

Bevilacqua, R. M.; Schwartz, P. R.; Wilson, W. J.; Ricketts, W. B.; Howard, R. J.

1985-01-01

91

Vapor explosions: A review of experiments for accident analysis  

SciTech Connect

A vapor explosion is a physical event in which a hot liquid (fuel) transfers its internal energy to a colder, more volatile liquid (coolant); thus the coolant vaporizes at high pressures and expands analyses work on its surroundings. In postulated severe accidents in current fission reactors, vapor explosions are considered if this molten {open_quotes}fuel{close_quotes} contacts residual water in-vessel or ex-vessel because these physical explosions have the potential to contribute to reactor vessel failure and possibly containment failure and release of radioactive fission products. Current safety analyses and probabilistic studies consider this process with the use of explosion models. Eventually these models must be compared with available experimental data to determine their validity. This study provides a comprehensive review of vapor explosion experiments for eventual use in such comparisons. Also, when there are insufficient data, experiments are suggested that can provide the needed information for future comparisons. This view may be useful for light-water-reactor as well as noncommercial reactor safety studies. 115 refs., 6 figs., 3 tabs.

Corradini, M.L.; Taleyarkhan, R.P.

1991-07-01

92

Characterization of Advanced Avalanche Photodiodes for Water Vapor Lidar Receivers  

NASA Technical Reports Server (NTRS)

Development of advanced differential absorption lidar (DIAL) receivers is very important to increase the accuracy of atmospheric water vapor measurements. A major component of such receivers is the optical detector. In the near-infrared wavelength range avalanche photodiodes (APD's) are the best choice for higher signal-to-noise ratio, where there are many water vapor absorption lines. In this study, characterization experiments were performed to evaluate a group of silicon-based APD's. The APD's have different structures representative of different manufacturers. The experiments include setups to calibrate these devices, as well as characterization of the effects of voltage bias and temperature on the responsivity, surface scans, noise measurements, and frequency response measurements. For each experiment, the setup, procedure, data analysis, and results are given and discussed. This research was done to choose a suitable APD detector for the development of an advanced atmospheric water vapor differential absorption lidar detection system operating either at 720, 820, or 940 nm. The results point out the benefits of using the super low ionization ratio (SLIK) structure APD for its lower noise-equivalent power, which was found to be on the order of 2 to 4 fW/Hz(sup (1/2)), with an appropriate optical system and electronics. The water vapor detection systems signal-to-noise ratio will increase by a factor of 10.

Refaat, Tamer F.; Halama, Gary E.; DeYoung, Russell J.

2000-01-01

93

Factors Controlling Upper-Troposphere Water Vapor  

Microsoft Academic Search

The seasonal changes of the upper-tropospheric humidity are studied with the water vapor data from the Microwave Limb Sounder on the National Aeronautics and Space Administration's Upper Atmosphere Research Satellite, and the winds and vertical velocity data obtained from the European Centre for Medium-Range Weather Forecasts. Using the same algorithm for vertical transport as that used for horizontal transport (by

Yong Zhu; Reginald E. Newell; William G. Read

2000-01-01

94

Sound Waves in Water Containing Vapor Bubbles  

Microsoft Academic Search

The rapid evaporation or condensation of a vapor bubble when out of equilibrium compared to the slow dissolving or growth of an air bubble results in quite different propagation properties of sound waves through water containing one or the other types of bubbles. Adapting a method developed by Foldy in his treatment of the air bubble case, we derive an

G. T. Trammell

1962-01-01

95

Applications II: Water Vapor and Atmospheric Dynamics  

NASA Technical Reports Server (NTRS)

Contents include the following: 1. Introduction. A case for using lidars in atmospheric dynamics will be made. 2. Scales of motion. Will discuss atmospheric scales of motion and lidar role in probing this various events. 3. Examples. We will discuss applications of lidars into atmospheric dynamics using data from case studies that illustrate different atmospheric phenomenon. Concluding statement. Water Vapor and Atmospheric Dynamics.

Demoz, Belay

2004-01-01

96

GOES Water Vapor: 1995 Hurricane Season  

NSDL National Science Digital Library

An animation of atmospheric water vapor over the Western Hemisphere for the period from May 5, 1995 through October 31, 1995, as measured by GOES. The animation shows the entire hemisphere, then zooms in to show the North Atlantic and the hurricanes during this period.

Shirah, Greg; Kekesi, Alex; Chesters, Dennis; Hasler, Fritz

1998-01-01

97

Advanced Water Vapor Lidar Detection System.  

National Technical Information Service (NTIS)

In the present water vapor lidar system, the detected signal is sent over long cables to a waveform digitizer in a CAMAC crate. This has the disadvantage of transmitting analog signals for a relatively long distance, which is subjected to pickup noise, le...

H. Elsayed-Ali

1998-01-01

98

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999-2000 winter season. Aircraft based water vapor, carbon monoxide, and ozone measurements are analyzed so as to establish how deeply tropospheric air mixes into the arctic lower-most stratosphere, and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to- stratosphere exchange extends into the arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases idly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of about 5 ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20\\% of the parcels which have ozone values of 300-350ppbv experiencing ice saturation in a given 10 day period. Third, during early Spring temperatures at the tropopause are cold enough so that 5-10\\% of parcels experience relative humidities above 100\\%, even if the water content is as low as 5 ppmv. The implication is that during, this period the arctic tropopause can play an important role in maintaining a very dry upper troposphere during early Spring.

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Podolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Hipskino, R. Stephen (Technical Monitor)

2001-01-01

99

Processes Controlling Water Vapor in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

This work describes transport and thermodynamic processes that control water vapor near the tropopause during the SAGE III-Ozone Loss and Validation Experiment (SOLVE), held during the Arctic 1999/2000 winter season. Aircraft-based water vapor, carbon monoxide, and ozone measurements were analyzed so as to establish how deeply tropospheric air mixes into the Arctic lowermost stratosphere and what the implications are for cloud formation and water vapor removal in this region of the atmosphere. There are three major findings. First, troposphere-to-stratosphere exchange extends into the Arctic stratosphere to about 13 km. Penetration is to similar levels throughout the winter, however, because ozone increases with altitude most rapidly in the early spring, tropospheric air mixes with the highest values of ozone in that season. The effect of this upward mixing is to elevate water vapor mixing ratios significantly above their prevailing stratospheric values of above 5ppmv. Second, the potential for cloud formation in the stratosphere is highest during early spring, with about 20% of the parcels which have ozone values of 300-350 ppbv experiencing ice saturation in a given 10 day period. Third, during early spring, temperatures at the troposphere are cold enough so that 5-10% of parcels experience relative humidities above 100%, even if the water content is as low as 5 ppmv. The implication is that during this period, dynamical processes near the Arctic tropopause can dehydrate air and keep the Arctic tropopause region very dry during early spring.

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Padolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Mahoney, Michael J.; Richard, Erik

2002-01-01

100

Climatology and interannual variability of diurnal water vapor heating  

Microsoft Academic Search

Tropospheric heating by water vapor insolation absorption is a leading drive of the propagating diurnal tide. A climatology of monthly diurnal radiative heating due to water vapor insolation absorption is derived using specific humidity from NCEP\\/NCAR reanalyses, and global precipitable water from the NASA Water Vapor Project. The new climatology complements and extends an existing one published by Groves in

R. S. Lieberman; D. A. Ortland; E. S. Yarosh

2001-01-01

101

Mars: Water Vapor Observations From the Viking Orbiters  

Microsoft Academic Search

The results of observations of the spatial and temporal variation of water vapor during the Viking primary mission are reported. The instrument, the Mars atmospheric water detector (Mawd), is a fivechannel grating spectrometer operating in the 1.4-tm water vapor bands. The seasonal period covered here is the northern summer solstice to the following equinox. The global water vapor, mapped at

C. B. Farmer; D. W. Davies; A. L. Holland; D. D. Laporte; P. E. Doms

1977-01-01

102

The effect of water vapor on the release of fission gas from the fuel elements of high temperature, gas-cooled reactors: A preliminary assessment of experiments HRB-17, HFR-B1, HFR-K6 and KORA  

SciTech Connect

The effect of water vapor on the release of fission gas from the fuel elements of high temperature, gas-cooled reactors has been measured in different laboratories under both irradiation and post irradiation conditions. The data from experiments HRB-17, HFR-B1, HFR-K6, and in the KORA facility are compared to assess their consistency and complimentarily. The experiments are consistent under comparable experimental conditions and reveal two general mechanisms involving exposed fuel kernels embedded in carbonaceous materials. One is manifest as a strong dependence of fission gas release on the partial pressure of water vapor below 1 kPa and the other, as a weak dependence above 1 kPa.

Myers, B.F.

1995-09-01

103

Water vapor permeability of plastics used for electrolyte immobilized lead-acid battery containers  

Microsoft Academic Search

The water vapor permeability (WVP) properties of three polymer resins used for battery container materials were investigated. The resins were acrylonitrile-butadine-styrene (ABS), poly(vinyl chloride) (PVC) and polypropylene (PP). The water vapor transmission rate through each plastic was determined according to ASTM E96-80, Water Vapor Transmission of Materials. Experiments were performed at 2% relative humidity and a temperature range of 21-50°C.

F. J. Vaccaro; J. A. Klatte

1989-01-01

104

Visualization of Atmospheric Water Vapor Data for SAGE  

NASA Technical Reports Server (NTRS)

The goal of this project was to develop visualization tools to study the water vapor dynamics using the Stratospheric Aerosol and Gas Experiment 11 (SAGE 11) water vapor data. During the past years, we completed the development of a visualization tool called EZSAGE, and various Gridded Water Vapor plots, tools deployed on the web to provide users with new insight into the water vapor dynamics. Results and experiences from this project, including papers, tutorials and reviews were published on the main Web page. Additional publishing effort has been initiated to package EZSAGE software for CD production and distribution. There have been some major personnel changes since Fall, 1998. Dr. Mou-Liang Kung, a Professor of Computer Science assumed the PI position vacated by Dr. Waldo Rodriguez who was on leave. However, former PI, Dr. Rodriguez continued to serve as a research adviser to this project to assure smooth transition and project completion. Typically in each semester, five student research assistants were hired and trained. Weekly group meetings were held to discuss problems, progress, new research direction, and activity planning. Other small group meetings were also held regularly for different objectives of this project. All student research assistants were required to submit reports for conference submission.

Kung, Mou-Liang; Chu, W. P. (Technical Monitor)

2000-01-01

105

Widespread water vapor emission in Orion  

NASA Astrophysics Data System (ADS)

We have discovered spatially extended emission in the 313 - 220 line of water vapor in Orion. This is the first time that extended water emission has been found in the interstellar medium. Many strong narrow features with flux density approx. (1 - 15) x 103 Jy have been detected around Ori A-IRc2. These features appear superposed over a weaker (approx. 103 Jy high velocity plateau with a half-power size of approx. equals 45 sec, and a total extent of 80 sec x 80 sec. Narrow lines with intensities approx. 25 - 200 Jy, are detected at the velocity of the molecular cloud for all the positions observed along the molecular ridge. These lines are not arising from point sources and the different emission regions are well resolved by our 15 sec beam. Narrow and blueshifted emission is also found along a filament containing the S6 source 100 sec south of IRc2. From statistical equilibrium and radiative transfer calculations for the physical conditions of the Orion molecular cloud, we conclude that the nature of the observed water vapor emission is dominated by maser emission. The water abundance is estimated to be larger than 10-5, implying that water vapor is a substantial component of the gas phase in warm molecular clouds and one of its most important gas coolants.

Cernicharo, J.; Gonzalez-Alfonso, E.; Alcolea, J.; Bachiller, R.; John, D.

1994-09-01

106

Tunable lasers for water vapor measurements and other lidar applications  

NASA Technical Reports Server (NTRS)

A tunable dye laser suitable for differential absorption (DIAL) measurements of water vapor in the troposphere was constructed. A multi-pass absorption cell for calibration was also constructed for use in atmospheric DIAL measurements of water vapor.

Gammon, R. W.; Mcilrath, T. J.; Wilkerson, T. D.

1977-01-01

107

G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) Value-Added Product  

SciTech Connect

The G-Band Vapor Radiometer Precipitable Water Vapor (GVRPWV) value-added product (VAP) computes precipitable water vapor using neural network techniques from data measured by the GVR. The GVR reports time-series measurements of brightness temperatures for four channels located at 183.3 ± 1, 3, 7, and 14 GHz.

Koontz, A; Cadeddu, M

2012-12-05

108

Operating a radio-frequency plasma source on water vapor  

Microsoft Academic Search

A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas

Sonca V. T. Nguyen; John E. Foster; Alec D. Gallimore

2009-01-01

109

Seasonal variability of mesospheric water vapor  

NASA Technical Reports Server (NTRS)

Ground-based spectral line measurements of the 22.2 GHz atmospheric water vapor line in emission were made at the JPL in order to obtain data in a dry climate, and to confirm similar measurements made at the Haystack Observatory. The results obtained from March 1984 to July 1984 and from December 1984 to May 1985, were based on data recorded by a HP9816 microcomputer. The instrument spectrometer was a 64 channel, 62.5 kHz resolution filter bank. Data indicates the existence of a seasonal variation in the abundance of water vapor in the upper mesosphere, with mixing ratios higher in summer than in spring. This is consistent with recent theoretical and observational results. In the area of semiannual oscillation, Haystack data are more consistent than those of JPL, indicating an annual cycle with abundances at maximum in summer and minimum in winter.

Schwartz, P. R.; Bevilacqua, R. M.; Wilson, W. J.; Ricketts, W. B.; Howard, R. J.

1985-01-01

110

High temperature water vapor electrolysis (HOT ELLY)  

NASA Astrophysics Data System (ADS)

The practicability of high temperature water vapor electrolysis was demonstrated on a laboratory scale. The component raw materials selection is described, and the manufacture of high temperature electrolysis cells is delineated. Electrolytic operation of single cells and of tubular batteries built of series connected cells, at ambient as well as at high pressure, is described. Results show that the specific electrical energy necessary for this method of hydrogen production is significantly lower than in conventional electrolysis processes.

Doenitz, W.; Hermeking, H.; Kitzmann, I.; Koch, A.; Roettenbacher, R.; Schaefer, W.; Schmidberger, R.; Schumacher, J.; Vonzuelow, H.

1980-08-01

111

Quality and Control of Water Vapor Winds  

NASA Technical Reports Server (NTRS)

Water vapor imagery from the geostationary satellites such as GOES, Meteosat, and GMS provides synoptic views of dynamical events on a continual basis. Because the imagery represents a non-linear combination of mid- and upper-tropospheric thermodynamic parameters (three-dimensional variations in temperature and humidity), video loops of these image products provide enlightening views of regional flow fields, the movement of tropical and extratropical storm systems, the transfer of moisture between hemispheres and from the tropics to the mid- latitudes, and the dominance of high pressure systems over particular regions of the Earth. Despite the obvious larger scale features, the water vapor imagery contains significant image variability down to the single 8 km GOES pixel. These features can be quantitatively identified and tracked from one time to the next using various image processing techniques. Merrill et al. (1991), Hayden and Schmidt (1992), and Laurent (1993) have documented the operational procedures and capabilities of NOAA and ESOC to produce cloud and water vapor winds. These techniques employ standard correlation and template matching approaches to wind tracking and use qualitative and quantitative procedures to eliminate bad wind vectors from the wind data set. Techniques have also been developed to improve the quality of the operational winds though robust editing procedures (Hayden and Veldon 1991). These quality and control approaches have limitations, are often subjective, and constrain wind variability to be consistent with model derived wind fields. This paper describes research focused on the refinement of objective quality and control parameters for water vapor wind vector data sets. New quality and control measures are developed and employed to provide a more robust wind data set for climate analysis, data assimilation studies, as well as operational weather forecasting. The parameters are applicable to cloud-tracked winds as well with minor modifications. The improvement in winds through use of these new quality and control parameters is measured without the use of rawinsonde or modeled wind field data and compared with other approaches.

Jedlovec, Gary J.; Atkinson, Robert J.

1996-01-01

112

Improved cell for water-vapor electrolysis  

NASA Technical Reports Server (NTRS)

Continuous-flow electrolytic cells decompose water vapor in steam and room air into hydrogen and oxygen. Sintered iridium oxide catalytic anode coating yields dissociation rates hundredfold greater than those obtained using platinum black. Cell consists of two mirror-image cells, with dual cathode sandwiched between two anodes. Gas traverses serpentine channels within cell and is dissociated at anode. Oxygen mingles with gas stream, while hydrogen migrates through porous matrix and is liberated as gas at cathode.

Aylward, J. R.

1981-01-01

113

Water vapor and cloud water measurements over Darwin during the STEP 1987 tropical mission  

NASA Technical Reports Server (NTRS)

Measurements of stratospheric and upper tropospheric cloud water plus water vapor (total water) and water vapor were made with two Lyman alpha hygrometers as part of the STEP tropical experiment. The in situ measurements were made in the Darwin, Australia, area in January and February of 1987 on an ER-2 aircraft. Average stratospheric water vapor at a potential temperature of 375 K (the average value of Theta at the tropopause) was 2.4 parts per million by volume (ppmv). This water mixing ratio is below the 3.0 to 4.0 ppmv necessary to be consistent with the observed upper stratospheric dryness. Saturation with respect to ice and the potential for dehydration was observed up to Theta = 402 K.

Kelly, K. K.; Proffitt, M. H.; Chan, K. R.; Loewenstein, M.; Podolske, J. R.; Strahan, E.; Wilson, J. C.; Kley, D.

1993-01-01

114

Hydrogen isotope measurement corrections for low water vapor concentrations: Mauna Loa Observatory, Hawaii  

Microsoft Academic Search

We present a comparison of laser spectroscopy measurements and traditional mass spectrometry techniques for measuring the hydrogen isotope composition of atmospheric water vapor. Laboratory experiments indicate that the Picarro gas analyzer has a negative relationship between inverse concentration and D\\/H ratio, so flask measurements were used to calibrate the laser spectroscopy systems at low water vapor concentrations and assess linearity.

L. R. Johnson; Z. D. Sharp; J. Galewsky; M. H. Strong; A. D. van Pelt; F. Dong; D. C. Noone

2010-01-01

115

Effects of vertical distribution of water vapor and temperature on total column water vapor retrieval error  

SciTech Connect

The author looks at the systematic error introduced into the extraction of total column water vapor from the special sensor microwave/imager (SSM/I) by means of the Wentz retrieval algorithm. As part of this algorithm the parameters of globally averaged temperature and water vapor profiles are estimated from in situ data. It is known that the vertical structures of temperature and water vapor are not uniform globally. This variation can cause systematic errors in the retrieval of relevant data from the raw data. Here the author investigates the influence of using monthly mean vertical temperature and water vapor profiles from the European Center for Medium Range Weather Forecasts, in contrast to the global average values used by Wentz. For 70% of the global ocean area the errors are within 0.1 g cm[sup [minus]2]. Regions are identified where larger biases are introduced because of temperature structures, wind effects, and the presence of large amounts of water vapor.

Sun, J. (Oregon State Univ., Corvallis (United States))

1993-04-15

116

Estimating Water Vapor Transport Using a Multiple Satellite Network  

NASA Astrophysics Data System (ADS)

The purpose of this study is to demonstrate the viability of estimating water vapor transport using polar orbiting satellite data. Columnar water vapor estimates are obtained from microwave radiometers with a high degree of accuracy using the Wentz retrieval algorithm. Feature tracking techniques are applied to the water vapor data to estimate the transport vector without resorting to the use of ancillary data (such as analysis wind fields). Successful use of feature tracking is made possible by the large number of satellites used in this study. We use data from 2003 when six radiometers were available: 3 SSMI on the DMSP satellites, TMI on the TRMM satellite, AMSR-E on Aqua, and AMSR on Midori-II. Feature tracking has been used with GOES water vapor imagery to estimate water vapor transport, however these estimates are more indicative of the upper-tropospheric water vapor. Our estimates are more representative of the vertically averaged water vapor transport. We will present 1-degree by 1-degree monthly maps of the zonal and meridional components of water vapor transport as well as water vapor divergence. We will include comparisons of our estimates of the zonal and meridional transport with estimates from existing model analysis, radiosondes, and GOES water vapor transport. We will also present comparisons between our estimates of water vapor divergence and satellite-derived evaporation minus precipitation estimates to assess how far we are from closing the atmospheric branch of the hydrological cycle over the oceans using satellite data alone.

Hilburn, K.; Wentz, F.

2004-12-01

117

Assimilation of TES Water Vapor Observations  

NASA Technical Reports Server (NTRS)

The Thermal Emission Spectrometer (TES) on the Mars Global Surveyor has made extensive observations of the Martian atmospheric water vapor column since the beginning of its mapping mission in early 1999. The results show broad agreement with the earlier Viking Mars Atmospheric Water Detector (MAWD) results (though column amounts in southern summer are higher, perhaps due to dust obscuration during the Viking mission). General circulation model (GCM) simulations of the annual Martian water cycle also show broad agreement with the TES observations. Details of the simulations depend on cloud and boundary layer parameterizations and on the adsorbing properties of the regolith. In order to make quantitative assessments of this agreement and to obtain observational values for the required physical parameters, a tracer transport data assimilation model has been developed. Model winds are derived from both tracer measurements and retrieved atmospheric temperature structures, providing a useful check of the underlying dynamical core of the GCM. By allowing detailed intercomparison between spacecraft and ground-based observations of Martian water vapor, the model should also contribute significantly to our understanding of the diurnal water cycle.

Houben, Howard; DeVincenzi, D. (Technical Monitor)

2002-01-01

118

Transient water vapor at Europa's south pole.  

PubMed

In November and December 2012, the Hubble Space Telescope (HST) imaged Europa's ultraviolet emissions in the search for vapor plume activity. We report statistically significant coincident surpluses of hydrogen Lyman-? and oxygen OI 130.4-nanometer emissions above the southern hemisphere in December 2012. These emissions were persistently found in the same area over the 7 hours of the observation, suggesting atmospheric inhomogeneity; they are consistent with two 200-km-high plumes of water vapor with line-of-sight column densities of about 10(20) per square meter. Nondetection in November 2012 and in previous HST images from 1999 suggests varying plume activity that might depend on changing surface stresses based on Europa's orbital phases. The plume was present when Europa was near apocenter and was not detected close to its pericenter, in agreement with tidal modeling predictions. PMID:24336567

Roth, Lorenz; Saur, Joachim; Retherford, Kurt D; Strobel, Darrell F; Feldman, Paul D; McGrath, Melissa A; Nimmo, Francis

2014-01-10

119

Daytime Raman lidar measurements of water vapor during the ARM 1997 water vapor intensive observation period  

SciTech Connect

Because of the importance of water vapor, the ARM program initiated a series of three intensive operating periods (IOPs) at its CART (Cloud And Radiation Testbed) site. The goal of these IOPs is to improve and validate the state-of-the-art capabilities in measuring water vapor. To date, two of the planned three IOPs have occurred: the first was in September of 1996, with an emphasis on the lowest kilometer, while the second was conducted from September--October 1997 with a focus on both the upper troposphere and lowest kilometer. These IOPs provided an excellent opportunity to compare measurements from other systems with those made by the CART Raman lidar. This paper addresses primarily the daytime water vapor measurements made by the lidar system during the second of these IOPs.

Turner, D.D. [Pacific Northwest National Lab., Richland, WA (United States); Goldsmith, J.E.M. [Sandia National Labs., Livermore, CA (United States)

1998-04-01

120

Trapping of water vapor from an atmosphere by condensed silicate matter formed by high-temperature pulse vaporization  

NASA Technical Reports Server (NTRS)

The origin of planetary atmospheres is thought to be the result of bombardment of a growing planet by massive planetesimals. According to some models, the accumulation of released water vapor and/or carbon dioxide can result in the formation of a dense and hot primordial atmosphere. Among source and sink processes of atmospheric water vapor the formation of hydroxides was considered mainly as rehydration of dehydrated minerals (foresterite and enstatite). From our point of view, the formation of hydroxides is not limited to rehydration. Condensation of small silicate particles in a spreading vapor cloud and their interaction with a wet atmosphere can also result in the origin of hydrated phases which have no genetic connections with initial water bearing minerals. We present results of two experiments of a simulated interaction of condensed silicate matter which originated during vaporization of dry clinopyroxene in a wet helium atmosphere.

Gerasimov, M. V.; Dikov, Yu. P.; Yakovlev, O. I.; Wlotzka, F.

1993-01-01

121

Limit of Metastability for Liquid and Vapor Phases of Water  

NASA Astrophysics Data System (ADS)

We report the limits of superheating of water and supercooling of vapor from Monte Carlo simulations using microscopic models with configurational enthalpy as the order parameter. The superheating limit is well reproduced. The vapor is predicted to undergo spinodal decomposition at a temperature of Tspvap=46±10 °C (0 °C ?Tspvap?100 °C) under 1 atm. The water-water network begins to form at the supercooling limit of the vapor. Three-dimensional water-water and cavity-cavity unbroken networks are interwoven at critically superheated liquid water; if either network breaks, the metastable state changes to liquid or vapor.

Cho, Woo Jong; Kim, Jaegil; Lee, Joonho; Keyes, Thomas; Straub, John E.; Kim, Kwang S.

2014-04-01

122

UV Discharge Lamp on Water Vapor  

NASA Astrophysics Data System (ADS)

The development of non-coherent sources of UV radiation based on safe and nontoxic gaseous mixtures have good aspect for different applications. Present paper for the first time reports about experimental investigations of high voltage pulse-periodic discharge in water vapor. The observed time integrated emission spectra in the range 250-325 nm at the estimated water vapor pressure 0.1 mm Hg shown tree different parts: part I (250-275 nm) is attributed to B-A electronic transition of hydtoxyl OH molecule; part II (275-300 nm) and part III (300-325) -- to the A-X electronic transition of OH molecule. The most intensive were the bands, connecting with vibration transitions (1-0) 283 nm and (1-1) 309 nm. No other radiating species were detected. Time-dependent measurement clearly indicated that the emission pulse coincides with current pulse and the electron impact processes defines the properties of the discharge emission. The average output power of the lamp was estimated 1.5 W at 0.2 % efficacy. The use of hard water D2O instead of H2O results the increasing of output power approximately to twice.

Shpenik, Yurij; Kelman, Volodymyr; Zhmenyak, Yurij; Heneral, Andrij

2008-10-01

123

LASE measurements of aerosols and water vapor during TARFOX  

NASA Technical Reports Server (NTRS)

The TARFOX (Tropospheric Aerosol Radiative Forcing Observational Experiment) intensive field campaign was designed to reduce uncertainties in estimates of the effects of anthropogenic aerosols on climate by measuring direct radiative effects and the optical, physical, and chemical properties of aerosols [1]. TARFOX was conducted off the East Coast of the United States between July 10-31, 1996. Ground, aircraft, and satellite-based sensors measured the sensitivity of radiative fields at various atmospheric levels to aerosol optical properties (i.e., optical thickness, phase function, single-scattering albedo) and to the vertical profile of aerosols. The LASE (Lidar Atmospheric Sensing Experiment) instrument, which was flown on the NASA ER-2 aircraft, measured vertical profiles of total scattering ratio and water vapor during a series of 9 flights. These profiles were used in real-time to help direct the other aircraft to the appropriate altitudes for intensive sampling of aerosol layers. We have subsequently used the LASE aerosol data to derive aerosol backscattering and extinction profiles. Using these aerosol extinction profiles, we derived estimates of aerosol optical thickness (AOT) and compared these with measurements of AOT from both ground and airborne sun photometers and derived from the ATSR-2 (Along Track and Scanning Radiometer 2) sensor on ERS-2 (European Remote Sensing Satellite-2). We also used the water vapor mixing ratio profiles measured simultaneously by LASE to derive precipitable water vapor and compare these to ground based measurements.

Ferrare, Richard A.; Ismail, Syed; Browell, Edward V.; Brackett, Vincent G.; Kooi, Susan A.; Clayton, Marian B.; Melfi, Harvey; Whiteman, David N.; Schwenner, Geary; Evans, Keith D.; Hobbs, Peter V.; Veefkind, J. Pepijn; Russell, Philip B.; Livingston, John M.; Hignett, Philip; Holben, Brent N.; Remer, Lorraine A.

1998-01-01

124

Calibration of Atmospherically Induced Delay Fluctuations Due to Water Vapor  

NASA Technical Reports Server (NTRS)

We have completed a new generation of water vapor radiometers (WVR), the A- series, in order to support radio science experiments with the Cassini spacecraft. These new instruments sense three frequencies in the vicinity of the 22 GHz emission line of atmospheric water vapor within a 1 degree beamwidth from a clear aperture antenna that is co-pointed with the radio telescope down to 10 degree elevation. The radiometer electronics features almost an order of magnitude improvement in temperature stability compared with earlier WVR designs. For many radio science experiments, the error budget is likely to be dominated by path delay fluctuations due to variable atmospheric water vapor along the line-of-sight to the spacecraft. In order to demonstrate the performance of these new WVRs we are attempting to calibrate the delay fluctuations as seen by a radio interferometer operating over a 21 km baseline with a WVR near each antenna. The characteristics of these new WVRs will be described and the results of our preliminary analysis will be presented indicating an accuracy of 0.2 to 0.5 mm in tracking path delay fluctuations over time scales of 10 to 10,000 seconds.

Resch, George; Jacobs, Christopher; Keihm, Steve; Lanyi, Gabor; Naudet, Charles; Riley, Abraham; Rosenberger, Hans; Tanner, Alan

2000-01-01

125

Validation of the Harvard Lyman-? in situ water vapor instrument: Implications for the mechanisms that control stratospheric water vapor  

NASA Astrophysics Data System (ADS)

Building on previously published details of the laboratory calibrations of the Harvard Lyman-? photofragment fluorescence hygrometer (HWV) on the NASA ER-2 and WB-57 aircraft, we describe here the validation process for HWV, which includes laboratory calibrations and intercomparisons with other Harvard water vapor instruments at water vapor mixing ratios from 0 to 10 ppmv, followed by in-flight intercomparisons with the same Harvard hygrometers. The observed agreement exhibited in the laboratory and during intercomparisons helps corroborate the accuracy of HWV. In light of the validated accuracy of HWV, we present and evaluate a series of intercomparisons with satellite and balloon borne water vapor instruments made from the upper troposphere to the lower stratosphere in the tropics and midlatitudes. Whether on the NASA ER-2 or WB-57 aircraft, HWV has consistently measured about 1-1.5 ppmv higher than the balloon-borne NOAA/ESRL/GMD frost point hygrometer (CMDL), the NOAA Cryogenic Frost point Hygrometer (CFH), and the Microwave Limb Sounder (MLS) on the Aura satellite in regions of the atmosphere where water vapor is <10 ppmv. Comparisons in the tropics with the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite show large variable differences near the tropopause that converge to ˜10% above 460 K, with HWV higher. Results we show from the Aqua Validation and Intercomparison Experiment (AquaVIT) at the AIDA chamber in Karlsruhe do not reflect the observed in-flight differences. We illustrate that the interpretation of the results of comparisons between modeled and measured representations of the seasonal cycle of water entering the lower tropical stratosphere is dictated by which data set is used.

Weinstock, E. M.; Smith, J. B.; Sayres, D. S.; Pittman, J. V.; Spackman, J. R.; Hintsa, E. J.; Hanisco, T. F.; Moyer, E. J.; St. Clair, J. M.; Sargent, M. R.; Anderson, J. G.

2009-12-01

126

The roles of the saturation vapor pressure and water vapor partial pressure in controlling different stages of the polar mesospheric cloud season  

Microsoft Academic Search

SOFIE (Solar Occultation For Ice Experiment) daily zonal mean temperature (T), water vapor (H2O), and PMC measurements made from the AIM satellite, have been used to study the roles of temperature and water vapor in controlling the start, end, and PMC variability during the 2007 to 2009 northern summer PMC seasons. A necessary condition for PMCs to exist is that

P. Rong; J. Russell; M. E. Hervig; S. M. Bailey

2010-01-01

127

Measuring Water Vapor: The Microwave Water Radiometer (MWR)  

NSDL National Science Digital Library

This middle/junior high school computer activity asks students to use the data from a microwave water radiometer (MWR)in Oklahoma to find patterns in daily and seasonal water vapor levels. An extension for the effect of clouds includes comparison of data from millimeter wave cloud radar (MMCR). The activity is part of the Atmospheric Visualization Collection (AVC), which focuses on data from the Atmospheric Radiation Measurement (ARM) program's Southern Great Plains Cloud and Radiation Testbed site.

2003-05-09

128

Support for the Harvard University Water Vapor and Total Water Instruments for the 2004 NASA WB57 Middle Latitude Cirrus Experiment  

NASA Technical Reports Server (NTRS)

In order to improve our understanding of the role clouds play in the climate system, NASA is investing considerable effort in characterizing clouds with instruments ranging from passive remote sensors on board the EOS platforms, to the forthcoming active remote sensors on Cloudsat and Calipso. These missions, when taken together, have the capacity to advance our understanding of the coupling between various components of the hydrologic cycle and the atmospheric circulation, and hold the additional potential of leading to significant improvements in the characterization of cloud feedbacks in global models. This is especially true considering that several of these platforms will be flown in an identical orbit within several minutes of one another-a constellation of satellites known as the A-Train. The algorithms that are being implemented and developed to convert these new data streams from radiance and reflectivity measurements into geophysical parameters invariably rely on some set of simplifymg assumptions and empirical constants. Uncertainties in these relationships lead to poorly understood random and systematic errors in the retrieved properties. This lack of understanding introduces ambiguity in interpreting the data and in using the global data sets for their intended purposes. In light of this, a series of flights with the W57F was proposed to address certain specific issues related to the basic properties of mid latitude cirrus clouds: the NASA WE357 Middle Latitude Cirrus Experiment ("MidCiX"). The science questions addressed are: 1) Can cloud property retrieval algorithms developed for A-Train active and passive remote sensing measurements accurately characterize the microphysical properties of synoptic and convectively generated cirrus cloud systems? 2) What are the relationships between the cirrus particle mass, projected area, and particle size spectrum in various genre of cirrus clouds? 3) Does the present compliment of state of the art in situ cloud probes provide the level of precision and accuracy needed to develop and validate algorithms and to contribute to our understanding of the characteristics and microphysical processes operating in cirrus clouds?

Anderson, James G.

2005-01-01

129

Temperature and Water Vapor Pressure Effects on the Friction Coefficient of Hydrogenated Diamondlike Carbon Films.  

National Technical Information Service (NTIS)

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior th...

A. Erdemir N. Argibay O. L. Eryilmaz P. L. Dickrell W. G. Sawyer

2009-01-01

130

Water vapor measurements by Raman lidar during the ARM 1997 water vapor intensive observation period  

SciTech Connect

Water vapor is the most important greenhouse gas in the atmosphere, as it is the most active infrared absorber and emitter of radiation, and it also plays an important role in energy transport and cloud formation. Accurate, high resolution measurements of this variable are critical in order to improve the understanding of these processes and thus their ability to model them. Because of the importance of water vapor, the Department of Energy`s Atmospheric Radiation Measurement (ARM) program initiated a series of three intensive operating periods (IOPs) at its Cloud and Radiation Testbed (CART) site in northern Oklahoma. The goal of these IOPs is to improve and validate the state-of-the-art capabilities in measuring water vapor. To date, two of the planned three IOPs have occurred: the first was in September of 1996, with an emphasis on the lowest kilometer, while the second was conducted from September--October 1997 with a focus on both the upper troposphere and lowest kilometer. The ARM CART site is the home of several different water vapor measurement systems. These systems include a Raman lidar, a microwave radiometer, a radiosonde launch site, and an instrumented tower. During these IOPs, additional instrumentation was brought to the site to augment the normal measurements in the attempt to characterize the CART instruments and to address the need to improve water vapor measurement capabilities. Some of the instruments brought to the CART site include a scanning Raman lidar system from NASA/GSFC, additional microwave radiometers from NOAA/ETL, a chilled mirror that was flown on a tethersonde and kite system, and dewpoint hygrometer instruments flow on the North Dakota Citation. This paper will focus on the Raman lidar intercomparisons from the second IOP.

Turner, D.D. [Pacific Northwest National Lab., Richland, WA (United States); Whiteman, D.N.; Schwemmer, G.K. [National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Evans, K.D. [Univ. of Maryland, Baltimore, MD (United States)]|[National Aeronautics and Space Administration, Greenbelt, MD (United States). Goddard Space Flight Center; Melfi, S.H. [Univ. of Maryland, Baltimore, MD (United States); Goldsmith, J.E. [Sandia National Labs., Livermore, CA (United States)

1998-04-01

131

Hurricane Isabel, Amount of Atmospheric Water Vapor Observed By AIRS  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Figure 1

These false-color images show the amount of atmospheric water vapor observed by AIRS two weeks prior to the passage of Hurricane Isabel, and then when it was a Category 5 storm. The region shown includes parts of South America and the West Indies. Puerto Rico is the large island below the upper left corner.

Total water vapor represents the depth of a layer if all the water vapor in the atmosphere were to condense and fall to the surface. The color bar on the right sides of the plots give the thickness of this layer in millimeters (mm). The first image, from August 28, shows typical tropical water vapor amounts over the ocean: between roughly 25 and 50 mm, or 1 to 2 inches. The highest values of roughly 80 mm, seen as a red blob over South America, corresponds to intense thunderstorms. Thunderstorms pull in water vapor from surrounding regions and concentrate it, with much of it then falling as rain.

Figure 1 shows total water during the passage of Hurricane Isabel on September 13. The storm is apparent: the ring of moderate values surrounding a very strong maximum of 100 mm. Total water of more than 80 mm is unusual, and these values correspond to the intense thunderstorms contained within Isabel. The thunderstorms--and the large values of total water--are fed by evaporation from the ocean in the hurricane's high winds. The water vapor near the center of the storm does not remain there long, since hurricane rain rates as high 50 mm (2 inches) per hour imply rapid cycling of the water we observe. Away from the storm the amount of total water vapor is rather low, associated with fair weather where air that ascended near the storm's eye returns to earth, having dropped its moisture as rain. Also seen in the second images are two small regions of about 70 mm of total water over south America. These are yet more thunderstorms, though likely much more benign than those in Isabel.

The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

2003-01-01

132

Numerical simulation of water injection into vapor-dominated reservoirs  

Microsoft Academic Search

Water injection into vapor-dominated reservoirs is a means of condensate disposal, as well as a reservoir management tool for enhancing energy recovery and reservoir life. We review different approaches to modeling the complex fluid and heat flow processes during injection into vapor-dominated systems. Vapor pressure lowering, grid orientation effects, and physical dispersion of injection plumes from reservoir heterogeneity are important

K. Pruess

1995-01-01

133

Mass spectrometry for water vapor measurements in the UT/LS  

NASA Astrophysics Data System (ADS)

Water vapor in the lower stratosphere plays a crucial role for the atmospheric radiation budget (Solomon et al., 2011). However, large uncertainties remain in measuring atmospheric water vapor mixing ratios below 10 ppmv typical for the lower stratosphere. To this end, we have developed the Atmospheric Ionization Mass Spectrometer (AIMS) for the accurate and fast detection of water vapor in the UT/LS from aircraft. In the AIMS instrument atmospheric air is directly ionized in a discharge ion source and the resulting water vapor clusters H3O+(H2O)n (n = 0..3) are detected with a linear quadrupole mass spectrometer as a direct measure of the atmospheric water vapor mixing ratio. AIMS is calibrated in-flight with a H2O calibration source using the catalytic reaction of H2 and O2 on a heated platinum surface to form gaseous H2O. This calibration setup combined with the water vapor mass spectrometry offers a powerful technical development in atmospheric hygrometry, enriching existing H2O measurement techniques by a new independent method. Here, we present AIMS water vapor measurements performed during the CONCERT2011 campaign (Contrail and Cirrus Experiment) with the DLR research aircraft Falcon. In September 2011 a deep stratospheric intrusion was probed over northern Europe with a dynamical tropopause lowered down to 6 km. We found sharp humidity gradients between tropospheric and stratospheric air at the edge of the tropopause fold, which we crossed 4 times at altitudes between 6 and 11 km. In the center of the tropopause fold, we measured water vapor mixing ratios down to 4 ppmv. The observed water vapor distribution is compared to water vapor analysis fields of the ECMWF's Integrated Forecast System (IFS) to evaluate the representation water vapor in this specific meteorological situation.

Kaufmann, S.; Voigt, C.; Schäuble, D.; Schäfler, A.; Schlager, H.; Thornberry, T. D.; Fahey, D. W.

2012-12-01

134

Diode laser study of high-pressure water vapor spectroscopy  

Microsoft Academic Search

Measurements of water vapor are relevant to combustion, since water vapor concentration can be related to performance parameters such as combustion and propulsion efficiencies, and heat release. The development of a diode-laser based diagnostic to monitor water vapor and temperature in high-pressure and -temperature environments relevant to combustion by probing near-IR H 2O absorption features near 7117 and 7185 cm-1

Venu Nagali

1999-01-01

135

Interactions between aerosol, water vapor, and solar radiation  

NASA Astrophysics Data System (ADS)

A quantitative understanding of how clouds, aerosols and atmospheric gases affect the solar radiation absorbed by earth's climate systems is still largely unknown. This dissertation makes calibrated and precise (<1%) measurements of broadband and spectral solar radiation, and integrates these measurements with state-of-the-art radiative transfer models to clarify the roles of water vapor and aerosols in the solar heating of the atmosphere and ocean. The first part of the dissertation uses instantaneous surface, aircraft and satellite broadband (0.2-2.8 ?m) solar flux measurements collected during the Central Equatorial Pacific Experiment to establish that the atmospheric absorption in this moist region is 20% +/- 2% (89 +/- 7 W m -2) of the 441 W m-2 incident at the top-of-the-atmosphere. A radiative transfer model containing simultaneously observed water vapor profiles accurately predicts the instantaneous surface irradiance over a range of 35-50 kg m-2 of column water vapor. Precise 0.94 ?m direct solar transmission measurements collected during the ARM Enhanced Shortwave Experiment validate correlated-k atmospheric absorption calculations to within 5% at the center of this strong water vapor vibration rotation band. Together, these studies have significantly focused an active debate regarding the role of water vapor in regulating atmospheric solar absorption. The second part of the dissertation used two laboratory- calibrated multi-spectral photodiode radiometers during the Indian Ocean Experiment (INDOEX) to accurately quantify surface aerosol forcing, the aerosol-induced reduction of surface solar radiation. The global and diffuse irradiance data agree to within 5 W m-2 of results calculated by a Monte Carlo radiative transfer model that assumes an aerosol consistent with simultaneously measured aerosol properties. The monthly mean 0.4-0.7 ?m forcing for the region is -7.6 +/- 1.5 W m-2 during 1998 and -16.0 +/- 1.5 W m-2 during 1999. These precise estimates serve as a ground-truth for the broad scope of surface aerosol forcing studies conducted during INDOEX. Extrapolated to the broadband, the forcing is -13 W m-2 and -29 W m-2 for 1998 and 1999 respectively. Most of the surface cooling is caused by an average 0.5 K/day heating of the lower troposphere. Three years (1996-1998) of ship aerosol optical depth measurements find a surface forcing gradient of -16 W m-2 between the Arabian Sea and the South Indian Ocean.

Conant, William Christopher

136

The Water Vapor Abundance in Circumstellar Envelopes  

NASA Astrophysics Data System (ADS)

The maser emission of the para-H2O 313-->220 line at 183 GHz in O-rich evolved stars has been modeled to account for the empirical characteristics of this line reported by González-Alfonso et al. Likewise, efforts have been made to derive water vapor abundance in these sources. The Sobolev or large velocity gradient (LVG) method has been employed to study the intensity of this line as a function of source properties and physical conditions (i.e., mass-loss rate, p-H2O abundance, velocity field, kinetic temperature profile, stellar luminosity, and the set of collisional rates adopted in the calculations). It has been found that the intensity of the 313-->220 line is sensitive to the mass-loss rate, the p-H2O abundance, and the terminal velocity of the envelope, but it is rather insensitive to the rest of the parameters in stars with high mass-loss rates (?>10-6 Msolar yr-1). The models reproduce the main spectral characteristics of the emission at 183 GHz in the latter sources. A global fit to the data proves that the observational luminosities can be explained by assuming an H2O abundance relative to H2 [x(H2O)] of 1-2×10-4. Detailed fitting to the line profile in five selected objects yields a similar value for x(H2O). The validity of the LVG approach has been verified by modeling the maser emission at 183 GHz through a nonlocal radiative transfer code. The model calculations with both methods lead to similar results. The pumping of the first bending mode of water vapor through absorption of photons emitted by the dust and the star has been also simulated. This effect is found to be important in the pumping of the H2O rotational levels. Hence, in order to recover LVG results, the water abundance must be increased by a factor of ~2 for stars with high mass-loss rates. Consequently, x(H2O) has been estimated to be 3×10-4 within a factor ~=2. With this value for x(H2O), the expected near- and far-infrared spectra of the circumstellar envelopes of O-rich stars for several mass-loss rates have also been computed. Hence, it is possible to predict that, in some stars, the ro-vibrational lines of the 6 ?m water vapor band with wavelengths longer that 6.3 ?m--the P-branch--can be observed in emission, rather than in absorption.

González-Alfonso, Eduardo; Cernicharo, José

1999-11-01

137

Vertical Distribution of Water in the Near-Equatorial Troposphere of Mars: Water Vapor and Clouds  

Microsoft Academic Search

Solar occultation spectrometry of the martian atmosphere was performed during the Phobos mission with the Auguste experiment in the UV, visible, and NIR spectral ranges. The entire domain of data in the range of 1.9 ?m has been reanalyzed to retrieve all available information about the water vapor vertical profile. Accurate consideration of the instrumental corrections and a probabilistic concept

A. V. Rodin; O. I. Korablev; V. I. Moroz

1997-01-01

138

Measurement of atmospheric precipitable water using a solar radiometer. [water vapor absorption effects  

NASA Technical Reports Server (NTRS)

A technique is described and tested that allows the determination of atmospheric precipitable water from two measurements of solar intensity: one in a water-vapor absorption band and another in a nearby spectral region unaffected by water vapor.

Pitts, D. E.; Dillinger, A. E.; Mcallum, W. E.

1974-01-01

139

Aircraft water vapor measurements utilizing an aluminum oxide hygrometer  

NASA Technical Reports Server (NTRS)

A hygrometer for water vapor measurements from an aircraft was developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on the NASA Convair 990 and on a USAF B-57 aircraft. Water vapor measurements from the Convair 990 were conducted up to 40,000 ft with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 ft.

Hilsenrath, E.

1974-01-01

140

Aircraft water vapor measurements utilizing an aluminum oxide hygrometer  

NASA Technical Reports Server (NTRS)

A hygrometer for water vapor measurements from an aircraft has been developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on NASA and USAF aircraft. Water vapor measurements were conducted up to 40,000 feet with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 feet.

Hilsenrath, E.

1973-01-01

141

Holographic studies of the vapor explosion of vaporizing water-in-fuel emulsion droplets  

NASA Technical Reports Server (NTRS)

Holographic studies were performed which examined the fragmentation process during vapor explosion of a water-in-fuel (hexadecane/water) emulsion droplet. Holograms were taken at 700 to 1000 microseconds after the vapor explosion. Photographs of the reconstructed holograms reveal a wide range of fragment droplet sizes created during the explosion process. Fragment droplet diameters range from below 10 microns to over 100 microns. It is estimated that between ten thousand and a million fragment droplets can result from this extremely violent vapor explosion process. This enhanced atomization is thus expected to have a pronounced effect on vaporization processes which are present during combustion of emulsified fuels.

Sheffield, S. A.; Hess, C. F.; Trolinger, J. D.

1982-01-01

142

SOIL VAPOR EXTRACTION COLUMN EXPERIMENTS ON GASOLINE CONTAMINATED SOIL  

EPA Science Inventory

Soil vapor extraction (SVE) is a technique that is used to remove volatile organic compounds from unsaturated soils. Air is pumped through and from the contaminated zone to remove vapor phase constituents. In the work, laboratory soil column experiments were conducted using a gas...

143

Water Vapor Enhancement in Prescribed Fire Plumes  

NASA Astrophysics Data System (ADS)

In situ radiosonde measurements were obtained during multiple prescribed fires at the Joseph W. Jones Ecological Research Center at Ichauway, Georgia in March and July of 2008. Data were obtained from prescribed fires conducted in longleaf pine ecosystems. After significant smoke generation was observed, radiosondes were launched downwind of the fire front and rose directly into the smoke plumes. Radiosondes were also launched before each burn to obtain ambient background conditions. This provided a unique dataset of smoke plume moisture to determine how moisture enhancement from fire smoke alters the dynamics of the smoke plume. Preliminary analysis of results show moisture enhancement occurred in all smoke plumes with relative humidity values increasing by 10 to 30 percent and water vapor mixing ratios increasing by 1 to 4 g kg-1. Understanding the moisture enhancement in prescribed fire smoke plumes will help determine the convective dynamics that occur in major wildland fires and convection columns.

Kiefer, C. M.; Clements, C. B.; Potter, B. E.; Strenfel, S. J.

2008-12-01

144

Mars Atmospheric Water Vapor: 2000 Southern Summer  

NASA Astrophysics Data System (ADS)

During 1998-2000 extensive ground-based observations yielded 133 continuous, H2O vapor profiles across the Martian disk. High-dispersion, CCD echelle spectra sampled Martian atmospheric water vapor from northern spring through the start of summer in the southern hemisphere. The slit was placed either in the N-S direction along the central meridian to study the latitudinal distribution or E-W to study the diurnal behavior. Abundances will be presented for the late spring-early summer season in the southern hemisphere. Supported by NASA grant NAG5-7791. Martian Water Vapor Spectra: 1998-2000 Apparition Date Slit Slit Ls SubS Martian SubE Mars (UTC) pos pos Lat Long Lat Dia. 1998 N-S E-W (o) (o) (o) (o) (") Nov 10-12 6 - 56 20.5 88-163 25.1 4.8 Dec 8-9 3 3 68 23.3 136-180 24.2 5.4 1999 Jan 12-13 6 3 83 25.2 167-200 20.8 6.8 Jan 20-1 4 2 91 25.5 357-48 18.6 7.9 Mar 16-17 2 11 111 23.8 227-306 15.0 12.1 Mar 29 2 - 116 22.7 122-137 15.4 13.7 Jun 1-2 1 5 148 13.7 170-212 22.7 14.4 Jun 22 1 1 158 9.1 323-351 22.8 12.3 Jul 7-10 6 13 168 5.8 140-207 22.0 11.0 Jul 27-28 3 3 178 1.1 318-11 19.6 8.0 Aug 30-31 2 7 197 -7.1 314-37 12.7 8.0 Sep 23-24 5 5 212 -12.9 77-125 6.0 7.1 Nov 8-9 4 6 242 -21.9 336-33 -8.7 6.0 Nov 29-2 10 7 254 -24.3 86-161 -15.3 5.6 2000 Jan 16-17 11 - 284 -24.7 0-44 -25.4 4.8 Feb 9 4 - 298 -22.2 123-148 -26.3 4.5

Barker, E.

2000-12-01

145

Operating a radio-frequency plasma source on water vapor  

SciTech Connect

A magnetically enhanced radio-frequency (rf) plasma source operating on water vapor has an extensive list of potential applications. In this work, the use of a rf plasma source to dissociate water vapor for hydrogen production is investigated. This paper describes a rf plasma source operated on water vapor and characterizes its plasma properties using a Langmuir probe, a residual gas analyzer, and a spectrometer. The plasma source operated first on argon and then on water vapor at operating pressures just over 300 mtorr. Argon and water vapor plasma number densities differ significantly. In the electropositive argon plasma, quasineutrality requires n{sub i}{approx_equal}n{sub e}, where n{sub i} is the positive ion density. But in the electronegative water plasma, quasineutrality requires n{sub i+}=n{sub i-}+n{sub e}. The positive ion density and electron density of the water vapor plasma are approximately one and two orders of magnitude lower, respectively, than those of argon plasma. These results suggest that attachment and dissociative attachment are present in electronegative water vapor plasma. The electron temperature for this water vapor plasma source is between 1.5 and 4 eV. Without an applied axial magnetic field, hydrogen production increases linearly with rf power. With an axial magnetic field, hydrogen production jumps to a maximum value at 500 W and then saturates with rf power. The presence of the applied axial magnetic field is therefore shown to enhance hydrogen production.

Nguyen, Sonca V. T.; Gallimore, Alec D. [Plasmadynamics and Electric Propulsion Laboratory, University of Michigan, Ann Arbor, Michigan 48108 (United States); Foster, John E. [Plasma Science and Technology Laboratory, University of Michigan, Ann Arbor, Michigan 48108 (United States)

2009-08-15

146

Characterization and mitigation of water vapor effects in the measurement of ozone by chemiluminescence with nitric oxide  

NASA Astrophysics Data System (ADS)

Laboratory experiments were conducted to investigate the effects of water vapor on the reaction of nitric oxide with ozone in a gas-phase chemiluminescence instrument used for fast response and high sensitivity detection of atmospheric ozone. Water vapor was introduced into a constant level ozone standard and both ozone and water vapor signals were recorded at 10 Hz. The presence of water vapor was found to reduce, i.e. quench, the ozone signal. A dimensionless correction factor was determined to be 4.15 ± 0.14 × 10-3, which corresponds to a 4.15% increase in the corrected ozone signal per 10 mmol mol-1 of co-sampled water vapor. An ozone-inert water vapor permeable membrane (a Nafion dryer with a counterflow of dry air from a compressed gas cylinder) was installed in the sampling line and was shown to remove the bulk of the water vapor in the sample air. At water vapor mole fractions above 25 mmol mol-1, the Nafion dryer removed over 75% of the water vapor in the sample. This reduced the required ozone signal correction from over 11% to less than 2.5%. The Nafion dryer was highly effective at reducing the fast fluctuations of the water vapor signal (more than 97%) while leaving the ozone signal unaffected, which is a crucial improvement for minimizing the quenching interference of water vapor fluxes and required density correction in the determination of ozone fluxes by the eddy covariance technique.

Boylan, P.; Helmig, D.; Park, J.-H.

2014-05-01

147

Water vapor and precipitation isotope ratios in Beijing, China  

Microsoft Academic Search

The objective of this study is to investigate the characteristics of ?D, ?18O, and deuterium excess (d) of precipitation and water vapor in surface air in Beijing, China. The ?D, ?18O, and d of atmospheric water vapor in surface air were measured continuously with an in situ technique. Much less day-to-day and diurnal variations in the vapor isotopic contents were

Xue-Fa Wen; Shi-Chun Zhang; Xiao-Min Sun; Gui-Rui Yu; Xuhui Lee

2010-01-01

148

Water vapor and precipitation isotope ratios in Beijing, China  

Microsoft Academic Search

The objective of this study is to investigate the characteristics of deltaD, delta18O, and deuterium excess (d) of precipitation and water vapor in surface air in Beijing, China. The deltaD, delta18O, and d of atmospheric water vapor in surface air were measured continuously with an in situ technique. Much less day-to-day and diurnal variations in the vapor isotopic contents were

Xue-Fa Wen; Shi-Chun Zhang; Xiao-Min Sun; Gui-Rui Yu; Xuhui Lee

2010-01-01

149

Influence of liquid water and water vapor on antimisting kerosene (AMK)  

NASA Technical Reports Server (NTRS)

Experiments have been performed to evaluate the compatibility of liquid water and water vapor with antimisting kerosenes (AMK) containing polymer additive FM-9 developed by Imperial Chemical Industries. This effort consists of the determination of water solubility in AMK, influence of water on restoration (degradation) of AMK, and effect of water on standard AMK quality control methods. The principal conclusions of this investigation are: (1) the uptake of water in AMK critically depends upon the degree of agitation and can be as high as 1300 ppm at 20 C, (2) more than 250 to 300 ppm of water in AMK causes an insoluble second phase to form. The amount of this second phase depends on fuel temperature, agitation, degree of restoration (degradation) and the water content of the fuel, (3) laboratory scale experiments indicate precipitate formation when water vapor comes in contact with cold fuel surfaces at a much lower level of water (125 to 150 ppm), (4) precipitate formation is very pronounced in these experiments where humid air is percolated through a cold fuel (-20 C), (5) laboratory tests further indicate that water droplet settling time is markedly reduced in AMK as compared to jet A, (6) limited low temperature testing down to -30 C under laboratory conditions indicates the formation of stable, transparent gels.

Yavrouian, A. H.; Sarolouki, M.; Sarohia, V.

1983-01-01

150

The Annual Cycle of Water Vapor on Mars as Observed by the Thermal Emission Spectrometer  

NASA Technical Reports Server (NTRS)

Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999-March 2001). A maximum in water vapor abundance is observed at high latitudes during mid-summer in both hemispheres, reaching a maximum value of approximately 100 pr-micrometer in the north and approximately 50 pr-micrometer in the south. Low water vapor abundance (<5 pr-micrometer) is observed at middle and high latitudes in the fall and winter of both hemispheres. There are large differences in the hemispheric (north versus south) and seasonal (perihelion versus aphelion) behavior of water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually-averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments shows some similar features, but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD and the large latitudinal gradient in annually-averaged water vapor observed by MAWD does not appear in the TES results.

Smith, Michael D.; Vondrak, Richard R. (Technical Monitor)

2001-01-01

151

COMBINING WATER VAPOR DATA FROM GPS AND MERIS  

Microsoft Academic Search

Improved knowledge of atmospheric water vapor and its temporal and spatial variability is of great scientic interest for climate research and weather prediction, but also geodetic positioning applications using GPS and radar interferometry will benet. In this article a comparison is made of MERIS and GPS based integrated water vapor data, retrieved at the same day over Western Europe. For

Roderik Lindenbergh; Maxim Keshin; Hans van der Marel; Ramon Hanssen

2006-01-01

152

Aircraft Water Vapor Measurements Utilizing an Aluminum Oxide Hygrometer  

Microsoft Academic Search

A hygrometer for water vapor measurements from an aircraft was developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on the NASA Convair 990 and on a USAF B-57 aircraft. Water vapor measurements from the Convair 990 were conducted up to 40,000 ft with penetration into the stratosphere. Good agreement was obtained with simultaneously

Ernest Hilsenrath

1974-01-01

153

Oxidation and Volatilization of Silica-Formers in Water Vapor.  

National Technical Information Service (NTIS)

At high temperatures SiC and Si3N4 react with water vapor to form a silica scale. Silica scales also react with water vapor to form a volatile Si(OH)4 species. These simultaneous reactions, one forming silica and the other removing silica, are described b...

E. J. Opila

2002-01-01

154

Detection of Thermal Water Vapor Emission from W Hydrae  

NASA Technical Reports Server (NTRS)

We have detected four far-infrared emission lines of water vapor toward the evolved star W Hydrae, using the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO). This is the first detection of thermal water vapor emission from a circumstellar outflow.

Neufeld, David A.; Chen, Wesley; Melnick, Gary J.; DeGraauw, Thijs; Feuchtgruber, Helmut; Harwitt, Martin

1997-01-01

155

Water Vapor Measurements from HALOE (1992-1997)  

NSDL National Science Digital Library

An animated graph showing HALOE measurements of the water vapor amounts in the upper stratosphere, illustrating that it takes about 5 years for CFCs to reach the upper atmosphere. Tropical water vapor changes slowly with seasonal cycles. These changes, shown here as thick bands, were found to slowly ascend. These measurements tell us how fast the CFCs and other pollutants rise into the stratosphere.

Mitchell, Horace; Schoeberl, Mark

1999-04-09

156

Mercury isotope fractionation during liquid–vapor evaporation experiments  

Microsoft Academic Search

Liquid–vapor mercury isotope fractionation was investigated under equilibrium and dynamic conditions. Equilibrium evaporation experiments were performed in a closed glass system under atmospheric pressure between 0 and 22°C, where vapor above the liquid was sampled at chemical equilibrium. Dynamic evaporation experiments were conducted in a closed glass system under 10?5bar vacuum conditions varying (1) the fraction of liquid Hg evaporated

Nicolas Estrade; Jean Carignan; Jeroen E. Sonke; Olivier F. X. Donard

2009-01-01

157

Detection of water vapor in Halley's comet  

NASA Technical Reports Server (NTRS)

Gaseous, neutral H2O was detected in the coma of comet Halley on 22.1 and 24.1 December 1985 Universal Time. Nine spectral lines of the nus band (2.65 micrometers) were found by means of a Fourier transform spectrometer on the NASA-Kuiper Airborne Observatory. The water production rate was about 6 x 10 to the 28th molecules per second on 22.1 December and 1.7 x 10 to the 29th molecules per second on 24.1 December UT. The numbers of spectral lines and their intensities are in accord with nonthermal-equilibrium cometary models. Rotational populations are derived from the observed spectral line intensities and excitation conditions are discussed. The ortho-para ratio was found to be 2.66 + or - 0.13, corresponding to a nuclear-spin temperature of 32 K (+5 K, -2 K), possibly indicating that the observed water vapor originated from a low-temperature ice.

Mumma, M. J.; Weaver, H. A.; Larson, H. P.; Williams, M.; Davis, D. S.

1986-01-01

158

Detection of Water Vapor in Halley's Comet.  

PubMed

Gaseous, neutral H(2)O was detected in the coma of comet Halley on 22.1 and 24.1 December 1985 Universal Time. Nine spectral lines of thev(3) band (2.65 micrometers) were found by means of a Fourier transform spectrometer (lambda/triangle uplambda approximately 10(5)) on the NASA-Kuiper Airborne Observatory. The water production rate was approximately 6 x 10(28) molecules per second on 22.1 December and 1.7 x 10(29) molecules per second on 24.1 December UT. The numbers of spectral lines and their intensities are in accord with nonthermal-equilibrium cometary models. Rotational populations are derived from the observed spectral line intensities and excitation conditions are discussed. The ortho-para ratio was found to be 2.66+/-0.13, corresponding to a nuclear-spin temperature of 32 K (+5 K, -2 K), possibly indicating that the observed water vapor originated from a low-temperature ice. PMID:17773501

Mumma, M J; Weaver, H A; Larson, H P; Davis, D S; Williams, M

1986-06-20

159

Temperature and water vapor pressure effects on the friction coefficient of hydrogenated diamondlike carbon films.  

SciTech Connect

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior that does not reoccur even after extended periods of exposure to low partial pressures of H{sub 2}O and O{sub 2}. Experiments varying both water vapor pressure and sample temperature show trends of a decreasing friction coefficient as a function of both the decreasing water vapor pressure and the increasing substrate temperature. Theses trends are examined with regard to first order gas-surface interactions. Model fits give activation energies on the order of 40 kJ/mol, which is consistent with water vapor desorption.

Dickrell, P. L.; Sawyer, W. G.; Eryilmaz, O. L.; Erdemir, A.; Energy Technology; Univ. of Florida

2009-07-01

160

ACA phase calibration scheme with the ALMA water vapor radiometers  

NASA Astrophysics Data System (ADS)

In Atacama Large Millimeter/submillimeter Array (ALMA) commissioning and science verification we have conducted a series of experiments of a novel phase calibration scheme for Atacama Compact Array (ACA). In this scheme water vapor radiometers (WVRs) devoted to measurements of tropospheric water vapor content are attached to ACA’s four total-power array (TP Array) antennas surrounding the 7 m dish interferometer array (7 m Array). The excess path length (EPL) due to the water vapor variations aloft is fitted to a simple two-dimensional slope using WVR measurements. Interferometric phase fluctuations for each baseline of the 7 m Array are obtained from differences of EPL inferred from the two-dimensional slope and subtracted from the interferometric phases. In the experiments we used nine ALMA 12-m antennas. Eight of them were closely located in a 70-m square region, forming a compact array like ACA. We supposed the most four outsiders to be the TP Array while the inner 4 antennas were supposed to be the 7 m Array, so that this phase correction scheme (planar-fit) was tested and compared with the WVR phase correction. We estimated residual root-mean-square (RMS) phases for 17- to 41-m baselines after the planar-fit phase correction, and found that this scheme reduces the RMS phase to a 70 - 90 % level. The planar-fit phase correction was proved to be promising for ACA, and how high or low PWV this scheme effectively works in ACA is an important item to be clarified.

Asaki, Yoshiharu; Matsushita, Satoki; Morita, Koh-Ichiro; Nikolic, Bojan

2012-09-01

161

Integrated atmospheric water vapor estimates from a regional GPS network  

NASA Astrophysics Data System (ADS)

Integrated atmospheric water vapor (IWV) estimates from a 15-station-wide network of Global Positioning System (GPS) receivers have been collected continuously since November 1997. The core of this network consists of five stations of the active GPS reference system in the Netherlands. A network with sufficient long baselines was chosen to secure the absolute accuracy of the GPS IWV data. Rapid satellite orbits available 12 to 24 hours after data acquisition are used in the processing of the GPS data, and IWV estimates are available with a typical delay of 1 day. Comparison of the GPS IWV data with data retrieved from a water vapor radiometer and radiosondes shows a good agreement. Different network configurations and processing strategies have been investigated to optimize the network and processing for future near-real-time use. In near-real-time applications, only predicted orbits are available; however, the accuracy of the predicted orbits is, in general, not sufficient for accurate IWV retrieval. We tested whether orbit relaxation, i.e., the simultaneous adjustment of orbit parameters during the processing of the GPS data, could increase the accuracy of the IWV estimates. During an experiment with orbit relaxation applied to predicted orbits a significant improvement of the accuracy of the GPS IWV data was found. The accuracy was comparable to GPS IWV data retrieved with final orbits, the most accurate orbit data available. Results of the experiments and the analysis of operational acquired data are presented.

Baltink, Henk Klein; van der Marel, Hans; van der Hoeven, André G. A.

2002-02-01

162

Processes Controlling Water Vapor in the Winter Arctic Stratospheric Middleworld  

NASA Technical Reports Server (NTRS)

Water vapor in the winter arctic stratospheric middleworld is import-an: for two reasons: (1) the arctic middleworld is a source of air for the upper Troposphere because of the generally downward motion, and thus its water vapor content helps determine upper tropospheric water, a critical part of the earth's radiation budget; and (2) under appropriate conditions, relative humidities will be large, even to the point of stratospheric cirrus cloud formation, leading to the production of active chlorine species that could destroy ozone. On a number of occasions during SOLVE, clouds were observed in the stratospheric middleworld by the DC-8 aircraft. These tended to coincide with regions of low temperatures, though some cases suggest water vapor enhancements due to troposphere-to-stratosphere transport. The goal of this work is to understand the importance of processes in and at the edge of the arctic stratospheric middleworld in determining water vapor at these levels. Specifically, is water vapor at these levels determined largely by the descent of air from above, or are clouds both within and at the edge of the stratospheric middleworld potentially important? How important is troposphere-to-stratosphere transport of air in determining stratospheric middleworld water vapor content? To this end, we will first examine the minimum saturation mixing ratios along theta/EPV tubes during the SOLVE winter and compare these with DC-8 water vapor observations. This will be a rough indicator of how high relative humidities can get, and the likelihood of cirrus cloud formation in various parts of the stratospheric middleworld. We will then examine saturation mixing ratios along both diabatic and adiabatic trajectories, comparing these values with actual aircraft water vapor observations, both in situ and remote. Finally, we will attempt to actually predict water vapor using minimum saturation mixing ratios along trajectories, cloud injection (derived from satellite imagery) along trajectories, and suitable initial conditions.

Pfister, Leonhard; Selkirk, Henry; Jensen, Eric; Sachse, Glenn; Podolske, James; Schoeberl, Mark; Browell, Edward; Ismail, Syed; Hipskind, R. Stephen (Technical Monitor)

2000-01-01

163

Climate and Ozone Response to Increased Stratospheric Water Vapor  

NASA Technical Reports Server (NTRS)

Stratospheric water vapor abundance affects ozone, surface climate, and stratospheric temperatures. From 30-50 km altitude, temperatures show global decreases of 3-6 K over recent decades. These may be a proxy for water vapor increases, as the Goddard Institute for Space Studies (GISS) climate model reproduces these trends only when stratospheric water vapor is allowed to increase. Observations suggest that stratospheric water vapor is indeed increasing, however, measurements are extremely limited in either spatial coverage or duration. The model results suggest that the observed changes may be part of a global, long-term trend. Furthermore, the required water vapor change is too large to be accounted for by increased production within the stratosphere, suggesting that ongoing climate change may be altering tropospheric input. The calculated stratospheric water vapor increase contributes an additional approximately equals 24% (approximately equals 0.2 W/m(exp 2)) to the global warming from well-mixed greenhouse gases over the past two decades. Observed ozone depletion is also better reproduced when destruction due to increased water vapor is included. If the trend continues, it could increase future global warming and impede stratospheric ozone recovery.

Shindell, Drew T.

2001-01-01

164

Water vapor: An extraordinary terahertz wave source under optical excitation  

NASA Astrophysics Data System (ADS)

In modern terahertz (THz) sensing and imaging spectroscopy, water is considered a nemesis to be avoided due to strong absorption in the THz frequency range. Here we report the first experimental demonstration and theoretical implications of using femtosecond laser pulses to generate intense broadband THz emission from water vapor. When we focused an intense laser pulse in water vapor contained in a gas cell or injected from a gas jet nozzle, an extraordinarily strong THz field from optically excited water vapor is observed. Water vapor has more than 50% greater THz generation efficiency than dry nitrogen. It had previously been assumed that the nonlinear generation of THz waves in this manner primarily involves a free-electron plasma, but we show that the molecular structure plays an essential role in the process. In particular, we found that THz wave generation from H2O vapor is significantly stronger than that from D2O vapor. Vibronic activities of water cluster ions, occurring naturally in water vapor, may possibly contribute to the observed isotope effect along with rovibrational contributions from the predominant monomers.

Johnson, Keith; Price-Gallagher, Matthew; Mamer, Orval; Lesimple, Alain; Fletcher, Clark; Chen, Yunqing; Lu, Xiaofei; Yamaguchi, Masashi; Zhang, X.-C.

2008-09-01

165

Observations of vaporizing water-in-fuel emulsion droplets  

SciTech Connect

These observations in a Leidenfrost-type experiment allowed one to distinguish between different mechanisms in the emulsion combustion process. Three events were observed: disruptions, heterogeneously nucleated vapor explosions, and homogeneously nucleated vapor explosions. The last event greatly enhances combustion. The cenospheres, carbospheres or oil-coke particles formed will be reduced or eliminated by the vapor explosions, and any small solid fragments are likely to be consumed in the enhanced combustion processes. (DLC)

Sheffield, S.A.; Baer, M.R.; Denison, G.J.

1980-01-01

166

A latitudinal survey of mesospheric and upper stratospheric water vapor  

NASA Technical Reports Server (NTRS)

As part of the LAtitudinal DIstribution of Middle Atmosphere Structure (LADIMAS) campaign, measurements of mesospheric and upper stratospheric water vapor concentration were made over a latitudinal range from 53 N to 63 S. The 22-GHz emission line of water vapor was observed by a new, portable, cryogenically cooled microwave radiometer that was carried on board the German research vessel Polarstern as it sailed from Bremerhaven, Germany, to the Antarctic during November and December, 1991. Water vapor profiles were obtained at approximately 5 deg latitude intervals for an altitude range of 40 to 80 km.

Croskey, C. L.; Martone, J. P.; Olivero, J. J.; Puliafito, S. E.

1994-01-01

167

Water-vapor content in the atmosphere of arid zone  

NASA Astrophysics Data System (ADS)

The variation in water-vapor content W in the atmosphere of the arid zone is studied. The seasonal oscillations in W for the arid zone are characterized by changes in the moisture content from 2.3 to 3.6 times during the transition from winter to summer. The summer-fall period is characterized by a well-expressed midday minimum of moisture content. In winter the moisture content monotonically decreases during the day. In spring the water-vapor content has a wide maximum in midday. The water-vapor content in the atmosphere during dust haze increases up to two times.

Abdullaev, S. F.; Maslov, V. A.; Nazarov, B. I.; Salikhov, T. Kh.

2014-03-01

168

Multiple-wavelength Raman lidar measurements of atmospheric water vapor  

SciTech Connect

Height profiles of atmospheric water vapor obtained using a multiple-wavelength Raman lidar are examined. The water vapor profiles exhibit vertical structure with scales on the order of the resolution of the lidar (75 m). To determine whether such structure is atmospheric in origin, measurements obtained simultaneously in a common volume at two independent wavelengths were compared. Correlation of the gradients of the water vapor profiles obtained from these two wavelengths yielded an average correlation factor of 0.88. It was also observed that for the given meteorological conditions, the vertical structure decorrelated with a time constant of approximately three hours. 7 refs., 4 figs., 1 tab.

Rajan, S.; Kane, T.J.; Philbrick, C.R. [Pennsylvania State Univ., University Park, PA (United States)] [Pennsylvania State Univ., University Park, PA (United States)

1994-11-15

169

Isobaric vapor-liquid equilibrium for ethanol + water + potassium nitrate  

Microsoft Academic Search

An increasing research interest in the determination of the salt effect in the vapor-liquid equilibrium of binary systems has developed over the last few decades due to the importance of distillation with salts in the separation of close boiling and azeotropic mixtures. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt

Ernesto Vercher; M. Pilar Peña; Antoni Martinez-Andreu

1996-01-01

170

Isobaric vapor-liquid equilibrium for ethanol + water + strontium nitrate  

Microsoft Academic Search

The effect of salts on the vapor-liquid equilibrium of solvent mixtures is of considerable interest in the separation of close boiling and azeotropic mixtures. The salt effect has been studied by many researchers. Most investigations have been limited to measurements on the saturated salt solutions. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + strontium nitrate (3) at various

Ernesto Vercher; M. Pilar Peña; Antoni Martinez-Andreu

1996-01-01

171

Isobaric vapor-liquid equilibria of water + ethanol + hexyl acetate  

SciTech Connect

The authors determined the isobaric vapor-liquid equilibrium data for the ternary system water + ethanol + hexyl acetate at 101.325 kPa using a distillation apparatus recycling both liquid and vapor phases. The results were compared with those predicted using group contribution methods. The UNIFAC method gave the best predictions.

Arce, A.; Soto, A. [Univ. of Santiago de Compostela (Spain). Chemical Engineering Dept.; Orge, B.; Tojo, J. [Univ. of Vigo (Spain). Chemical Engineering Dept.

1995-09-01

172

Chemical reaction between water vapor and stressed glass  

NASA Technical Reports Server (NTRS)

The crack velocity in soda-lime silicate glass was determined at room temperature at water-vapor pressures of 10 to 0.04 torr using the double torsion technique. A precracked glass specimen (70 x 16 x 1.6 mm) was placed in a vacuum chamber containing a four-point bending test apparatus. The plotted experimental results show that the crack propagation curve in water agrees fairly well with that of Wiederhorn (1967). Attention is given to the effect of water vapor pressure on crack velocity at K(I) = 550,000 N/m to the 3/2 power, with (Wiederhorn's data) or without N2 present. The plotted results reveal that the present crack velocity is about two orders of magnitude higher than that of Wiederhorn at high water-vapor conditions, but the difference decreases as the water-vapor concentration diminishes or the crack velocity slows down.

Soga, N.; Okamoto, T.; Hanada, T.; Kunugi, M.

1979-01-01

173

Comparison of Upper Tropospheric Water Vapor from AIRS and Cryogenic Frostpoint Hygrometers  

NASA Technical Reports Server (NTRS)

Upper tropospheric water vapor (UTWV) from the Atmospheric Infrared Sounder (AIRS) experiment on NASA's Aqua spacecraft has the potential of addressing several important climate questions. The specified AIRS system measurement uncertainty for water vapor is 20 percent absolute averaged over 2 km layers. Cryogenic frostpoint hygrometers (CFH) are balloon-borne water vapor sensors responsive from the surface into the lower stratosphere. Several dozen coincident, collocated CFH profiles have been obtained for AlRS validation. The combination of CFH sensitivity and sample size offers a statistically compelling picture of AIRS UTWV measurement capability. We present a comparison between CFH observations and AlRS retrievals. We focus on the altitude range from the middle troposphere up to heights at the limits of AlRS sensitivity to water vapor, believed to be around 100-1 50 hPa.

Fetzer, Eric J.; Vomel, Holger

2004-01-01

174

Tropical stratospheric water vapor measured by the microwave limb sounder (MLS)  

NASA Technical Reports Server (NTRS)

The lower stratospheric variability of equatorial water vapor, measured by the Microwave Limb Sounder (MLS), follows an annual cycle modulated by the quasi-biennial oscillation. At levels higher in the stratosphere, water vapor measurements exhibit a semi-annual oscillatory signal with the largest amplitudes at 2.2 and 1hPa. Zonal-mean cross sections of MLS water vapor are consistent with previous satellite measurements from the limb infrared monitor of the stratosphere (LIMS) and the stratospheric Aerosol and Gas Experiment 2 (SAGE 2) instruments in that they show water vapor increasing upwards and the polewards from a well defined minimum in the tropics. The minimum values vary in height between the retrieved 46 and 22hPa pressure levels.

Carr, E. S.; Harwood, R. S.; Mote, P. W.; Peckham, G. E.; Suttie, R. A.; Lahoz, W. A.; O'Neill, A.; Froidevaux, L.; Jarnot, R. F.; Read, W. G.

1995-01-01

175

Variations in middle atmospheric water vapor from 2004 to 2013  

NASA Astrophysics Data System (ADS)

show measurements of middle atmospheric water vapor as measured by two ground-based Water Vapor Millimeter-wave Spectrometer instruments and three satellite-based instruments: the Aura Microwave Limb Sounder, the Atmospheric Chemistry Experiment (ACE), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We also show CH4 measurements from the MIPAS and ACE instruments and use these to help interpret the H2O variations. We find that interannual changes in stratospheric H2O of ~0.5 ppmv, observed from Table Mountain, California, at 26 km and 40 km from 2010 to 2012, are caused primarily by dynamically driven changes in CH4 during this period. The interannual variations in H2O observed over Mauna Loa, Hawaii, are shown to be quite similar to the average variations observed over 50°S-50°N in the lower mesosphere; thus, we conclude that a single ground-based microwave instrument can provide a useful estimate of interannual globally averaged lower mesospheric H2O variations, even when such changes are as small as ~0.2-0.3 ppmv. We find that the increase of ~0.2-0.3 ppmv in H2O in the lower mesosphere since 2006 is qualitatively consistent with an increase in tropical tropopause temperature since around 2001.

Nedoluha, Gerald E.; Michael Gomez, R.; Allen, Doug R.; Lambert, Alyn; Boone, Chris; Stiller, Gabriele

2013-10-01

176

Active Raman sounding of the earth's water vapor field  

NASA Technical Reports Server (NTRS)

The typically weak cross-sections characteristic of Raman processes has historically limited their use in atmospheric remote sensing to nighttime application. However, with advances in instrumentation and techniques, it is now possible to apply Raman lidar to the monitoring of atmospheric water vapor, aerosols and clouds throughout the diurnal cycle. Upper tropospheric and lower stratospheric measurements of water vapor using Raman lidar are also possible but are limited to nighttime and require long integration times. However, boundary layer studies of water vapor variability can now be performed with high temporal and spatial resolution. This paper will review the current state-of-the-art of Raman lidar for high-resolution measurements of the atmospheric water vapor, aerosol and cloud fields. In particular, we describe the use of Raman lidar for mapping the vertical distribution and variability of atmospheric water vapor, aerosols and clouds throughout the evolution of dynamic meteorological events. The ability of Raman lidar to detect and characterize water in the region of the tropopause and the importance of high-altitude water vapor for climate-related studies and meteorological satellite performance are discussed.

Tratt, David M.; Whiteman, David N.; Demoz, Belay B.; Farley, Robert W.; Wessel, John E.

2005-01-01

177

Investigation of water vapor motion winds from geostationary satellites  

NASA Technical Reports Server (NTRS)

Motions deduced in animated water vapor imagery from geostationary satellites can be used to infer wind fields in cloudless regimes. For the past several years, CIMSS has been exploring this potentially important source of global-scale wind information. Recently, METEOSAT-3 data has become routinely available to both the U.S. operational and research community. Compared with the current GOES satellite, the METEOSAT has a superior resolution (5 km vs. 16 km) in its water vapor channel. Preliminary work: at CIMSS has demonstrated that wind sets derived from METEOSAT water vapor imagery can provide important upper-tropospheric wind information in data void areas, and can positively impact numerical model guidance in meteorological applications. Specifically, hurricane track forecasts can be improved. Currently, we are exploring methods to further improve the derivation and quality of the water vapor wind sets.

Velden, Christopher

1993-01-01

178

Stratospheric water vapor in the NCAR CCM2  

NASA Technical Reports Server (NTRS)

Results are presented of the water vapor distribution in a 3D GCM with good vertical resolution, a state-of-the-art transport scheme, and a realistic water vapor source in the middle atmosphere. In addition to water vapor, the model transported methane and an idealized clock tracer, which provides transport times to and within the middle atmosphere. The water vapor and methane distributions are compared with Nimbus 7 SAMS and LIMS data and with in situ measurements. It is argued that the hygropause in the model is maintained not by 'freeze-drying' at the tops of tropical cumulonimbus, but by a balance between two sources and one sink. Since the southern winter dehydration is unrealistically intense, this balance most likely does not resemble the balance in the real atmosphere.

Mote, Philip W.; Holton, James R.

1992-01-01

179

GROUND WATER SAMPLING OF VOCS IN THE WATER/CAPILLARY FRINGE AREA FOR VAPOR INTRUSION ASSESSMENT  

EPA Science Inventory

Vapor intrusion has recently been considered a major pathway for increased indoor air contamination from certain volatile organic contaminants (VOCs). The recent Draft EPA Subsurface Vapor Intrusion Guidance Document states that ground water samples should be obtained from the u...

180

Smart temperature-controlled water vapor permeable polyurethane film  

Microsoft Academic Search

Aim of this study was to develop a temperature-controlled polyurethane (PU) film for the application in film coated clothes. The PU film should be a smart one that can control its water vapor permeability (WVP) through temperature change. The study was carried out by increasing the water vapor permeability of various breathable\\/waterproof PU films through variations of their hard-to-soft-segment ratio,

Chia-Yen Lin; Ken-Hsuan Liao; Cheng-Feng Su; Chao-Hui Kuo; Kuo-Huang Hsieh

2007-01-01

181

CRISM Observations of Water Vapor and Carbon Monoxide  

NASA Technical Reports Server (NTRS)

Near-infrared spectra returned by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM, [1]) on-board the Mars Reconnaissance Orbiter (MRO) contain the clear spectral signature of several atmospheric gases including carbon dioxide (CO2), water vapor (H2O), and carbon monoxide (CO). Here we describe the seasonal and spatial mapping of water vapor and carbon dioxide for one full Martian year using CRISM spectra.

Smith, Michael D.; Wolff, Michael J.; Clancy, R. Todd

2008-01-01

182

Sensing atmospheric water vapor with the Global Positioning System  

Microsoft Academic Search

Global Positioning System (GPS) receivers, water vapor radiometers (WVRs), and surface meteorological equipment were operated at both ends of a 50-km baseline in Colorado to measure the precipitable water vapor (PWV) and wet delay in the line-of-sight to GPR satellites. Using high precision orbits, WVR-measured and GPS-inferred PWV differences between the two sites usually agreed to better than 1 mm.

Christian Rocken; Randolph Ware; Teresa Van Hove; Frederick Solheim; Chris Alber; James Johnson; Mike Bevis; Steven Businger

1993-01-01

183

MJO in EOS MLS Cloud Ice and Water Vapor  

NASA Astrophysics Data System (ADS)

MLS cloud ice and water vapor fields are used in conjunction with ECMWF analyses and TRMM rainfall rates to study spatial-temporal evolution of the Madden Julian Oscillation (MJO). MLS measurements provide unprecedented vertical resolution of ice and water vapor in the upper troposphere. MJO events are identified using extended empirical orthogonal function (EEEOF) analysis. Phase relationships between the fields and vertical correlations are examined.

Schwartz, M. J.; Waliser, D. E.; Tian, B.; Wu, D. L.; Jiang, J. H.; Read, W. G.; Li, J. F.

2006-12-01

184

Gas phase reaction of sulfur trioxide with water vapor  

Microsoft Academic Search

Sulfur trioxide (SO3) has long been known to react with water to produce sulfuric acid (H2S04). It has been commonly assumed that the gas phase reaction in the Earth`s atmosphere between SO3 and water vapor to produce sulfuric acid vapor is an important step in the production of sulfuric acid aerosol particles. The kinetics of the gas phase reaction of

C. E. Kolb; M. J. Molina; J. T. Jayne; R. F. Meads; D. R. Worsnop; A. A. Viggiano

1994-01-01

185

Water-vapor pressure control in a volume  

NASA Technical Reports Server (NTRS)

The variation with time of the partial pressure of water in a volume that has openings to the outside environment and includes vapor sources was evaluated as a function of the purging flow and its vapor content. Experimental tests to estimate the diffusion of ambient humidity through openings and to validate calculated results were included. The purging flows required to produce and maintain a certain humidity in shipping containers, storage rooms, and clean rooms can be estimated with the relationship developed here. These purging flows are necessary to prevent the contamination, degradation, and other effects of water vapor on the systems inside these volumes.

Scialdone, J. J.

1978-01-01

186

Logarithmic radiative effect of water vapor and spectral kernels  

NASA Astrophysics Data System (ADS)

kernels have become a useful tool in climate analysis. A set of spectral kernels is calculated using a moderate resolution atmospheric transmission code MODTRAN and implemented in diagnosing spectrally decomposed global outgoing longwave radiation (OLR) changes. It is found that the effect of water vapor on the OLR is in proportion to the logarithm of its concentration. Spectral analysis discloses that this logarithmic dependency mainly results from water vapor absorption bands (0-560 cm-1 and 1250-1850 cm-1), while in the window region (800-1250 cm-1), the effect scales more linearly to its concentration. The logarithmic and linear effects in the respective spectral regions are validated by the calculations of a benchmark line-by-line radiative transfer model LBLRTM. The analysis based on LBLRTM-calculated second-order kernels shows that the nonlinear (logarithmic) effect results from the damping of the OLR sensitivity to layer-wise water vapor perturbation by both intra- and inter-layer effects. Given that different scaling approaches suit different spectral regions, it is advisable to apply the kernels in a hybrid manner in diagnosing the water vapor radiative effect. Applying logarithmic scaling in the water vapor absorption bands where absorption is strong and linear scaling in the window region where absorption is weak can generally constrain the error to within 10% of the overall OLR change for up to eightfold water vapor perturbations.

Bani Shahabadi, Maziar; Huang, Yi

2014-05-01

187

Retrieval of Cloud Water and Water Vapor Contents from Doppler Radar Data in a Tropical Squall Line  

Microsoft Academic Search

This paper describes the retrieval of cloud water and water vapor contents from Doppler radar data. The convective part of a tropical squall line (22 June 1981) observed during the COPT 81 (Convection Profonde Tropicale 1981) West African experiment, was chosen for developing a two-dimensional and steady state model for the retrieval of these parameters. The model is based upon

Danièle Hauser; Paul Amayenc

1986-01-01

188

A WATER VAPOR MONITOR USING DIFFERENTIAL INFRARED ABSORPTION  

EPA Science Inventory

A water vapor monitor has been developed with adequate sensitivity and versatility for a variety of applications. Two applications for which the instrument has been designed are the continuous monitoring of water in ambient air and the measuring of the mass of water desorbed from...

189

Balloon Borne Soundings of Water Vapor, Ozone and Temperature in the Upper Tropospheric and Lower Stratosphere as Part of the Second SAGE III Ozone Loss and Validation Experiment (SOLVE-2)  

NASA Technical Reports Server (NTRS)

The main goal of our work was to provide in situ water vapor and ozone profiles in the upper troposphere and lower stratosphere as reference measurements for the validation of SAGE III water vapor and ozone retrievals. We used the NOAA/CMDL frost point hygrometer and ECC ozone sondes on small research balloons to provide continuous profiles between the surface and the mid stratosphere. The NOAA/CMDL frost point hygrometer is currently the only lightweight balloon borne instrument capable of measuring water vapor between the lower troposphere and middle stratosphere. The validation measurements were based in the arctic region of Scandinavia for northern hemisphere observations and in New Zealand for southern hemisphere observations and timed to coincide with overpasses of the SAGE III instrument. In addition to SAGE III validation we also tried to coordinate launches with other instruments and studied dehydration and transport processes in the Arctic stratospheric vortex.

Voemel, Holger

2004-01-01

190

The threshold of vapor channel formation in water induced by pulsed CO2 laser  

NASA Astrophysics Data System (ADS)

Water plays an important role in laser ablation. There are two main interpretations of laser-water interaction: hydrokinetic effect and vapor phenomenon. The two explanations are reasonable in some way, but they can't explain the mechanism of laser-water interaction completely. In this study, the dynamic process of vapor channel formation induced by pulsed CO2 laser in static water layer was monitored by high-speed camera. The wavelength of pulsed CO2 laser is 10.64 um, and pulse repetition rate is 60 Hz. The laser power ranged from 1 to 7 W with a step of 0.5 W. The frame rate of high-speed camera used in the experiment was 80025 fps. Based on high-speed camera pictures, the dynamic process of vapor channel formation was examined, and the threshold of vapor channel formation, pulsation period, the volume, the maximum depth and corresponding width of vapor channel were determined. The results showed that the threshold of vapor channel formation was about 2.5 W. Moreover, pulsation period, the maximum depth and corresponding width of vapor channel increased with the increasing of the laser power.

Guo, Wenqing; Zhang, Xianzeng; Zhan, Zhenlin; Xie, Shusen

2012-12-01

191

Water Vapor-Mediated Volatilization of High-Temperature Materials  

NASA Astrophysics Data System (ADS)

Volatilization in water vapor-containing atmospheres is an important and often unexpected mechanism of degradation of high-temperature materials during processing and in service. Thermodynamic properties data sets for key (oxy)hydroxide vapor product species that are responsible for material transport and damage are often uncertain or unavailable. Estimation, quantum chemistry calculation, and measurement methods for thermodynamic properties of these species are reviewed, and data judged to be reliable are tabulated and referenced. Applications of water vapor-mediated volatilization include component and coating recession in turbine engines, oxidation/volatilization of ferritic steels in steam boilers, chromium poisoning in solid-oxide fuel cells, vanadium transport in hot corrosion and degradation of hydrocracking catalysts, Na loss from Na ?"-Al2O3 tubes, and environmental release of radioactive isotopes in a nuclear reactor accident or waste incineration. The significance of water vapor-mediated volatilization in these applications is described.

Meschter, Peter J.; Opila, Elizabeth J.; Jacobson, Nathan S.

2013-07-01

192

Fan tomography of the tropospheric water vapor for the calibration of the Ka band tracking of the Bepi-Colombo spacecraft (MORE experiment).  

NASA Astrophysics Data System (ADS)

The radiosciences Bepi-Colombo MORE experiment will use X/X, X/Ka and Ka/Ka band radio links to make accurate measurements of the spacecraft range and range rate. Tropospheric zenith wet delays range from 1.5 cm to 10 cm, with high variability (less than 1000 s) and will impair these accurate measurements. Conditions vary from summer (worse) to winter (better), from day (worse) to night (better). These wet delays cannot be estimated from ground weather measurements and alternative calibration methods should be used in order to cope with the MORE requirements (no more than 3 mm at 1000 s). Due to the Mercury orbit, MORE measurements will be performed by daylight and more frequently in summer than in winter (from Northern hemisphere). Two systems have been considered to calibrate this wet delay: Water Vapour Radiometers (WVRs) and GPS receivers. The Jet Propulsion Laboratory has developed a new class of WVRs reaching a 5 percent accuracy for the wet delay calibration (0.75 mm to 5 mm), but these WVRs are expensive to build and operate. GPS receivers are also routinely used for the calibration of data from NASA Deep Space probes, but several studies have shown that GPS receivers can give good calibration (through wet delay mapping functions) for long time variations, but are not accurate enough for short time variations (100 to 1000 s), and that WVRs must be used to efficiently calibrate the wet troposphere delays over such time spans. We think that such a calibration could be done by assimilating data from all the GNSS constellations (GPS, GLONASS, Galileo, Beidou and IRNSS) that will be available at the time of the Bepi-Colombo arrival at Mercury (2021), provided that the underlying physics of the turbulent atmosphere and evapotranspiration processes are properly taken into account at such time scales. This implies to do a tomographic image of the troposphere overlying each Deep Space tracking station at time scales of less than 1000 s. For this purpose, we have developed a full representation of the wet refractivity of the atmosphere over the ground station along a basis of 3D Zernike functions with time-variable coefficients. We detail the algorithm and the covariance functions derived from radiosoundings that are used to constraint the inverse imaging of the wet troposphere at the target time scales, and give examples of such imaging from GPS data only.

Barriot, Jean-Pierre; Serafini, Jonathan; Sichoix, Lydie

2012-07-01

193

Measurements of Humidity in the Atmosphere: Validation Experiments (MOHAVE I and MOHAVE II). Results Overview and Implication for the Long-Term Lidar Monitoring of Water Vapor in the UT/LS  

NASA Technical Reports Server (NTRS)

1. MOHAVE+MOHAVE II = very successful. 2. MOHAVE -> Fluorescence was found to be inherent to all three participating lidars. 3. MOHAVE II -> Fluorescence was removed and agreement with CFH was extremely good up to 16-18 km altitude. 4. MOHAVE II -> Calibration tests revealed unsuspected shortfalls of widely used techniques, with important implications for their applicability to longterm measurements. 5. A factor of 5 in future lidar signal-to-noise ratio is reasonably achievable. When this level is achieved water vapor Raman lidar will become a key instrument for the long-term monitoring of water vapor in the UT/LS

Leblanc, Thierry; McDermid, I. S.; Vomel, H.; Whiteman, D.; Twigg, Larry; McGee, T. G.

2008-01-01

194

Vapor compression distiller and membrane technology for water revitalization  

NASA Technical Reports Server (NTRS)

Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied: one is absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation, able to easily produce condensed water under zero gravity, was investigated experimentally and through simulated calculation. The vapor compression distiller was studied experimentally and it offers significant energy savings for evaporation of water.

Ashida, A.; Mitani, K.; Ebara, K.; Kurokawa, H.; Sawada, I.; Kashiwagi, H.; Tsuji, T.; Hayashi, S.; Otsubo, K.; Nitta, K.

1987-01-01

195

High temperature oxidation of molybdenum in water vapor environments  

NASA Astrophysics Data System (ADS)

Molybdenum has recently gained attention as a candidate cladding material for use in light water reactors. Its excellent high temperature mechanical properties and stability under irradiation suggest that it could offer benefits to performance under a wide range of reactor conditions, but little is known about its oxidation behavior in water vapor containing atmospheres. The current study was undertaken to elucidate the oxidation behavior of molybdenum in water vapor environments to 1200 °C in order to provide an initial assessment of its feasibility as a light water reactor cladding. Initial observations indicate that at temperatures below 1000 °C, the kinetics of mass loss in water vapor would not be detrimental to cladding integrity during an off-normal event. Above 1000 °C, degradation is more rapid but remains slower than observed for optimized zirconium cladding alloys. The effect of hydrogen-water vapor and oxygen-water vapor mixtures on material loss was also explored at elevated temperatures. Parts-per-million levels of either hydrogen or oxygen will minimally impact performance, but hydrogen contents in excess of 1000 ppm were observed to limit volatilization at 1000 °C.

Nelson, A. T.; Sooby, E. S.; Kim, Y.-J.; Cheng, B.; Maloy, S. A.

2014-05-01

196

Isothermal vapor-liquid equilibria for methanol + ethanol + water, methanol + water, and ethanol + water  

Microsoft Academic Search

Isothermal vapor-liquid equilibria were measured for the ternary system methanol + ethanol + water and its constituent binary systems of methanol + water and ethanol + water at 323.15, 328.15, and 333.15 K. The apparatus that was used made it possible to control the measured temperature and total pressure by computer. The experimental binary data were correlated by the NRTL

Kiyofumi Kurihara; Kouichi Takeda; Kazuo Kojima; Tsuyoshi Minoura

1995-01-01

197

Visible and infrared spin scan radiometer atmospheric sounder water vapor and wind fields over Amazonia  

SciTech Connect

Both the mass and motion fields for Amazonia have been depicted using almost exclusively geostationary satellite data. Derived parameters include satellite retrievals of atmospheric temperature and dewpoint temperature, total precipitable water vapor, and cloud and water vapor winds. The capabilities of geostationary satellite data have been demonstrated at least four times a day for the period of May 5-8, 1987, during the Global Tropospheric Experiment/Amazon Boundary Layer Experiment. The satellite-derived information is able to resolve synoptic-scale atmospheric trends in space and time.

Schmit, T.J.; Brueske, K.F.; Smith, W.L. (Cooperative Institute for Meteorological Satellite Studies, Madison, WI (USA)); Menzel, W.P. (NOAA/National Environmental Satellite, Data, and Information Service, Madison, WI (USA))

1990-09-20

198

The observed day-to-day variability of Mars water vapor  

NASA Technical Reports Server (NTRS)

The diurnal variability of atmospheric water vapor as derived from the Viking MAWD data is discussed. The detection of day to day variability of atmospheric water would be a significant finding since it would place constraints on the nature of surface reservoirs. Unfortunately, the diurnal variability seen by the MAWD experiment is well correlated with the occurrence of dust and/or ice hazes, making it difficult to separate real variations from observational effects. Analysis of the day to day variability of water vapor in the Martian atmosphere suggests that the observations are, at certain locations and seasons, significantly affected by the presence of water-ice hazes. Because such effects are generally limited to specific locations, such as Tharsis, Lunae Planum, and the polar cap edge during the spring, the seasonal and latitudinal trends in water vapor that have been previously reported are not significantly affected.

Jakosky, Bruce M.; Lapointe, Michael R.; Zurek, Richard W.

1987-01-01

199

Comparison of columnar water vapor measurement during the fall 1997 ARM Intensive Observation Period: optical methods  

Microsoft Academic Search

Optical methods can provide water vapor data from ground-based, airborne or spaceborne measurements of direct or reflected sunlight in spectral channels in and adjacent to water vapor absorption bands. The water-vapor transmittance Tw derived from these measurements has to be translated into water vapor amounts. Although this relationship is well known qualitatively, it has proven difficult to quantify. Attempts to

B. Schmid; J. Michalsky; D. Slater; J. Barnard; R. Halthore; J. Liljegren; B. Holben; T. Eck; J. Livingston; P. Russell; T. Ingold

2000-01-01

200

Enthalpy of Vaporization by Gas Chromatography: A Physical Chemistry Experiment  

ERIC Educational Resources Information Center

An experiment is conducted to measure the enthalpy of vaporization of volatile compounds like methylene chloride, carbon tetrachloride, and others by using gas chromatography. This physical property was measured using a very tiny quantity of sample revealing that it is possible to measure the enthalpies of two or more compounds at the same time.

Ellison, Herbert R.

2005-01-01

201

Airborne DIAL and ground-based Raman lidar measurements of water vapor over the Southern Great Plains  

NASA Astrophysics Data System (ADS)

Measurements of water vapor profiles over the Southern Great Plains acquired by two different lidars are presented. NASA's airborne DIAL Lidar Atmospheric Sensing Experiment (LASE) system measured water vapor, aerosol, and cloud profiles during the ARM/FIRE Water Vapor Experiment (AFWEX) in November-December 2000 and during the International H2O Project (IHOP) in May-June 2002. LASE measurements acquired during AFWEX are used to characterize upper troposphere water vapor measured by ground-based Raman lidars, radiosondes, and in situ aircraft sensors. LASE measurements acquired during IHOP are being used to better understand the influence water vapor variability on the initiation of deep convection and to improve the quantification and prediction of precipitation associated with these storms. The automated Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar (CARL) has been routinely measuring profiles of water vapor mixing ratio, relative humidity, aerosol extinction, aerosol backscattering, and aerosol and cloud depolarization during both daytime and nighttime operations. Aerosol and water vapor profiles acquired since March 1998 are used to investigate the seasonal variability of the vertical distributions of water vapor and aerosols.

Ferrare, Richard A.; Browell, Edward V.; Ismail, Syed; Kooi, Susan; Brackett, Vince G.; Clayton, Marian; Notari, Anthony; Butler, Carolyn F.; Barrick, John; Diskin, Glenn; Lesht, Barry; Schmidlin, Frank J.; Turner, Dave; Whiteman, David; Miloshevich, Larry

2003-12-01

202

On the uptake of water vapor by ion irradiated polyimide  

NASA Astrophysics Data System (ADS)

It is known that ion-irradiated polymers are capable to adsorb dopants from solid, liquid or gaseous phases. For simple ambient atmosphere exposures, oxygen and water vapor are the most prominent dopants. Though the quantity of the latter one is not sufficient to be probed by conventional spectroscopic techniques, it can be detected indirectly via its ionic conductivity on applying a strong electric field along the track direction, as long as it is not yet masked by the intrinsic ion track conductivity, which is the case for low-fluence polymer irradiation. The conductivity is of similar order for most low-fluence irradiated polymers examined - namely 10-15-10-13 ?-1 cm-1. Water vapor uptake - as determined via the ion track conductivity - sensitively depends on the ambient air humidity, so that fresh low fluence irradiated polymers can act as humidity sensors. Aging however leads to rapid deterioration of this property within a week exposure time at ambient room temperature and pressure. The water vapor absorption process in tracks is reversible, and the amount of water retained depends specifically on the polymer. Thus, whereas for polyimide, polycarbonate, polypropylene, and polytetrafluoride some water vapor adsorption is detected, polymethylmethacrylate and polyethyleneterepthalate exhibit little or no effect. Moreover, uptake of water vapor is restricted to the latent ion tracks themselves, and is barely detectable in neighboring pristine material. It scales linearly with the deposition of electronic energy along the ion track.

Fink, D.; Klett, R.; Müller, M.; Hu, Xuanwen; Chadderton, L. T.; Wang, L.; Hillenbrand, J.

203

Improved waste water vapor compression distillation technology. [for Spacelab  

NASA Technical Reports Server (NTRS)

The vapor compression distillation process is a method of recovering potable water from crewman urine in a manned spacecraft or space station. A description is presented of the research and development approach to the solution of the various problems encountered with previous vapor compression distillation units. The design solutions considered are incorporated in the preliminary design of a vapor compression distillation subsystem. The new design concepts are available for integration in the next generation of support systems and, particularly, the regenerative life support evaluation intended for project Spacelab.

Johnson, K. L.; Nuccio, P. P.; Reveley, W. F.

1977-01-01

204

Behavior of hydroxide at the water\\/vapor interface  

Microsoft Academic Search

Hydroxide and hydronium, which represent the ionic products of water autolysis, exhibit a peculiar surface behavior. While consensus has been established that the concentration of hydronium cations is enhanced at the surface with respect to the bulk, the affinity of hydroxide anions for the water\\/vapor interface has been a subject of an ongoing controversy. On the one hand, electrophoretic and

Bernd Winter; Manfred Faubel; Robert Vácha; Pavel Jungwirth

2009-01-01

205

Electrolysis cell functions as water vapor dehumidifier and oxygen generator  

NASA Technical Reports Server (NTRS)

Water vapor is absorbed in hygroscopic electrolyte, and oxygen generated by absorbed water electrolysis at anode is added simultaneously to air stream. Cell applications include on-board aircraft oxygen systems, portable oxygen generators, oxygen concentration requirements, and commercial air conditioning and dehumidifying systems.

Clifford, J. E.

1971-01-01

206

Computer simulation of the NASA water vapor electrolysis reactor  

NASA Technical Reports Server (NTRS)

The water vapor electrolysis (WVE) reactor is a spacecraft waste reclamation system for extended-mission manned spacecraft. The WVE reactor's raw material is water, its product oxygen. A computer simulation of the WVE operational processes provided the data required for an optimal design of the WVE unit. The simulation process was implemented with the aid of a FORTRAN IV routine.

Bloom, A. M.

1974-01-01

207

An observationally based constraint on the water-vapor feedback  

NASA Astrophysics Data System (ADS)

The increase in atmospheric concentrations of water vapor with global warming is a large positive feedback in the climate system. Thus, even relatively small errors in its magnitude can lead to large uncertainties in predicting climate response to anthropogenic forcing. This study incorporates observed variability of water vapor over 2002-2009 from the Atmospheric Infrared Sounder instrument into a radiative transfer scheme to provide constraints on this feedback. We derive a short-term water vapor feedback of 2.2 ± 0.4 Wm-2K-1. Based on the relationship between feedback derived over short and long timescales in twentieth century simulations of 14 climate models, we estimate a range of likely values for the long-term twentieth century water vapor feedback of 1.9 to 2.8 Wm-2K-1. We use the twentieth century simulations to determine the record length necessary for the short-term feedback to approach the long-term value. In most of the climate models we analyze, the short-term feedback converges to within 15% of its long-term value after 25 years, implying that a longer observational record is necessary to accurately estimate the water vapor feedback.

Gordon, N. D.; Jonko, A. K.; Forster, P. M.; Shell, K. M.

2013-11-01

208

Data Report on Measurements of Precipitable Water Vapor and Cloud Liquid at Fort Sill, OK, SESAME 1979.  

National Technical Information Service (NTIS)

A two channel microwave radiometer was operated from March 29, 1979 to June 8, 1979 for the measurement of precipitable water vapor as part of the 1979 Severe Environmental Storms and Mesoscale Experiment (SESAME) program. The radiometers were located on ...

F. O. Guiraud J. Howard D. C. Hogg

1979-01-01

209

SWAS observations of water vapor in the Venus mesosphere  

NASA Astrophysics Data System (ADS)

We present the first detections of the ground-state H 216O ( 1-1) rotational transition (at 556.9 GHz) and the 13CO (5-4) rotational transition from the atmosphere of Venus, measured with the Submillimeter Wave Astronomy Satellite (SWAS). The observed spectral features of these submillimeter transitions originate primarily from the 70-100 km altitude range, within the Venus mesosphere. Observations were obtained in December 2002, and January, March, and July 2004, coarsely sampling one Venus diurnal period as seen from Earth. The measured water vapor absorption line depth shows large variability among the four observing periods, with strong detections of the line in December 2002 and July 2004, and no detections in January and March 2004. Retrieval of atmospheric parameters was performed using a multi-transition inversion algorithm, combining simultaneous retrievals of temperature, carbon monoxide, and water profiles under imposed constraints. Analysis of the SWAS spectra resulted in measurements or upper limits for the globally averaged mesospheric water vapor abundance for each of the four observation periods, finding variability over at least two orders of magnitude. The results are consistent with both temporal and diurnal variability, but with short-term fluctuations clearly dominating. These results are fully consistent with the long-term study of mesospheric water vapor from millimeter and submillimeter observations of HDO [Sandor, B.J., Clancy, R.T., 2005. Icarus 177, 129-143]. The December 2002 observations detected very rapid change in the mesospheric water abundance. Over five days, a deep water absorption feature consistent with a water vapor abundance of 4.5±1.5 parts per million suddenly gave way to a significantly shallower absorption, implying a decrease in the water vapor abundance by a factor of nearly 50 in less that 48 h. In 2004, similar changes in the water vapor abundance were measured between the March and July SWAS observing periods, but variability on time scales of less than a week was not detected. The mesospheric water vapor is expected to be in equilibrium with aerosol particles, primarily composed of concentrated sulfuric acid, in the upper haze layers of the Venus atmosphere. If true, moderate amplitude (10-15 K) variability in mesospheric temperature, previously noted in millimeter spectroscopy observations of Venus, can explain the rapid water vapor variability detected by SWAS.

Gurwell, Mark A.; Melnick, Gary J.; Tolls, Volker; Bergin, Edwin A.; Patten, Brian M.

2007-06-01

210

Design of Advanced Atmospheric Water Vapor Differential Absorption Lidar (DIAL) Detection System  

NASA Technical Reports Server (NTRS)

The measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The lidar atmospheric sensing experiment (LASE) is an instrument designed and operated by the Langley Research Center for high precision water vapor measurements. The design details of a new water vapor lidar detection system that improves the measurement sensitivity of the LASE instrument by a factor of 10 are discussed. The new system consists of an advanced, very low noise, avalanche photodiode (APD) and a state-of-the-art signal processing circuit. The new low-power system is also compact and lightweight so that it would be suitable for space flight and unpiloted atmospheric vehicles (UAV) applications. The whole system is contained on one small printed circuit board (9 x 15 sq cm). The detection system is mounted at the focal plane of a lidar receiver telescope, and the digital output is read by a personal computer with a digital data acquisition card.

Refaat, Tamer F.; Luck, William S., Jr.; DeYoung, Russell J.

1999-01-01

211

Analysis of the global ISCCP TOVS water vapor climatology  

NASA Technical Reports Server (NTRS)

A climatological examination of the global water vapor field based on a multiyear period of successfull satellite-based observations is presented. Results from the multiyear global ISCCP TIROS Operational Vertical Sounder (TOVS) water vapor dataset as operationally produced by NESDIS and ISCCP are shown. The methods employed for the retrieval of precipitable water content (PWC) utilize infrared measurements collected by the TOVS instrument package flown aboard the NOAA series of operational polar-orbiting satellites. Strengths of this dataset include the nearly global daily coverage, availability for a multiyear period, operational internal quality checks, and its description of important features in the mean state of the atmosphere. Weaknesses of this PWC dataset include that the infrared sensors are unable to collect data in cloudy regions, the retrievals are strongly biased toward a land-based radiosonde first-guess dataset, and the description of high spatial and temporal variability is inadequate. Primary consequences of these factors are seen in the underestimation of ITCZ water vapor maxima, and underestimation of midlatitude water vapor mean and standard deviation values where transient atmospheric phenomena contribute significantly toward time means. A comparison of TOVS analyses to SSM/I data over ocean for the month of July 1988 shows fair agreement in the magnitude and distribution of the monthly mean values, but the TOVS fields exhibit much less temporal and spatial variability on a daily basis in comparison to the SSM/I analyses. The emphasis of this paper is on the presentation and documentation of an early satellite-based water vapor climatology, and description of factors that prevent a more accurate representation of the global water vapor field.

Wittmeyer, Ian L.; Vonder Haar, Thomas H.

1994-01-01

212

Analysis of the global ISCCP TOVS water vapor climatology  

SciTech Connect

A climatological examination of the global water vapor field based on a multiyear period of successful satellite-based observations is presented. Results from the multiyear global ISCCP TOVS water vapor dataset as operationally produced by NESDIS and ISCCP are shown. The methods employed for the retrieval of precipitable water content (PWC) utilize infrared measurements collected by the TOVS instrument package flown aboard the NOAA series of operational polar-orbiting satellites. Strengths of this dataset include the nearly global daily coverage, availability for a multiyear period, operational internal quality checks, and its description of important features in the mean state of the atmosphere. Weaknesses of this PWC dataset include that the infrared sensors are unable to collect data in cloudy regions, the retrievals are strongly biased toward a land-based radiosonde first-guess dataset, and the description of high spatial and temporal variability is inadequate. Primary consequences of these factors are seen in the underestimation of ITCZ water vapor maxima, and underestimation of midlatitude water vapor mean and standard deviation values where transient atmospheric phenomena contribute significantly toward time means. A comparison of TOVS analyses to SSM/I data over ocean for the month of July 1988 shows fair agreement in the magnitude and distribution of the monthly mean values, but the TOVS fields exhibit much less temporal and spatial variability on a daily basis in comparison to the SSM/I analyses. The emphasis of this paper is on the presentation and documentation of an early satellite-based water vapor climatology, and description of factors that prevent a more accurate representation of the global water vapor field. 25 refs., 8 figs., 1 tab.

Wittmeyer, I.L.; Vonder Haar, T.H. (Colorado State Univ., Fort Collins, CO (United States))

1994-02-01

213

The response of stratospheric water vapor to a changing climate: Insights from in situ water vapor measurements  

NASA Astrophysics Data System (ADS)

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 O3, CO, CO2, 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.

Sargent, Maryann Racine

214

Global upper tropospheric/lower stratospheric water vapor from satellites  

NASA Astrophysics Data System (ADS)

The past decade has been a "golden age" for observations of middle atmospheric trace gas distributions from space since numerous satellite instruments have been in orbit. One of the most important trace species with respect to its impact on global climate and stratospheric chemistry is water vapor. The presentation will provide an overview on the currently available data base, and on climatologies derived from the satellite data sets covering the altitude range from the upper troposphere to the lower mesosphere. The current and planned efforts within the SPARC Water Vapor Assessment II (WAVAS II) to intercompare the available satellite data sets and perform a quality asssessment will be presented, with some focus on the difficulties which we are facing on the way to a consistent multi-instrument long-term data set covering the last 30 years. Finally, future perspectives for the continuation of middle atmosphere water vapor observations from space will be discussed.

Stiller, G. P.; Lossow, S.; Read, W.; Rosenlof, K. H.; Garcia-Comas, M.; Hervig, M. E.; Hoppel, K.; Remsberg, E. E.; Russell, J. M.; Thomason, L. W.; Urban, J.; Walker, K. A.; Weber, M.; Zawodny, J. M.

2012-12-01

215

Global upper tropospheric/lower stratospheric water vapor from satellites  

NASA Astrophysics Data System (ADS)

The past decade has been a "golden age" for observations of middle atmospheric trace gas distributions from space since numerous satellite instruments have been in orbit. One of the most important trace species with respect to its impact on global climate and stratospheric chemistry is water vapor. The presentation will provide an overview on the currently available data base, and on climatologies derived from the satellite data sets covering the altitude range from the upper troposphere to the lower mesosphere. The current and planned efforts within the SPARC Water Vapor Assessment II (WAVAS II) to intercompare the available satellite data sets and perform a quality asssessment will be presented, with some focus on the difficulties which we are facing on the way to a consistent multi-instrument long-term data set covering the last 30 years. Finally, future perspectives for the continuation of middle atmosphere water vapor observations from space will be discussed.

Stiller, Gabriele P.; Lossow, Stefan; Read, William G.; Rosenlof, Karen H.; Garcia-Comas, Maya; Hervig, Mark E.; Hoppel, Karl; Remsberg, Ellis E.; Russell, James M., III; Thomason, Larry W.; Urban, Joachim; Walker, Kaley A.; Weber, Mark; Zawodny, Joseph M.

2013-04-01

216

Atmospheric Precorrected Differential Absorption technique to retrieve columnar water vapor  

SciTech Connect

Differential absorption techniques are suitable to retrieve the total column water vapor contents from imaging spectroscopy data. A technique called Atmospheric Precorrected Differential Absorption (APDA) is derived directly from simplified radiative transfer equations. It combines a partial atmospheric correction with a differential absorption technique. The atmospheric path radiance term is iteratively corrected during the retrieval of water vapor. This improves the results especially over low background albedos. The error of the method for various ground reflectance spectra is below 7% for most of the spectra. The channel combinations for two test cases are then defined, using a quantitative procedure, which is based on MODTRAN simulations and the image itself. An error analysis indicates that the influence of aerosols and channel calibration is minimal. The APDA technique is then applied to two AVIRIS images acquired in 1991 and 1995. The accuracy of the measured water vapor columns is within a range of {+-}5% compared to ground truth radiosonde data.

Schlaepfer, D.; Itten, K.I. [Univ. of Zuerich (Switzerland). Dept. of Geography] [Univ. of Zuerich (Switzerland). Dept. of Geography; Borel, C.C. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States); Keller, J. [Paul Scherrer Inst., Villigen (Switzerland)] [Paul Scherrer Inst., Villigen (Switzerland)

1998-09-01

217

Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts  

Microsoft Academic Search

These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the

X. Wu; G. R. Diak; C. M. Hayden; J. A. Young

1995-01-01

218

Long-term Changes of Water Vapor in the Stratosphere  

NASA Astrophysics Data System (ADS)

Water vapor in the stratosphere plays an important role in the radiative and chemical balance of this region of the atmosphere. Although the basic processes controlling the water vapor distribution are known, details of the processes and the degree to which they are subject to change are less well understood. Longer term measurements of water vapor in the stratosphere are very limited. The only continuing measurement of water vapor in the stratosphere with a multi-decadal record is the balloon profile measurements from Boulder, Colorado that began in 1980. These soundings done on an approximately monthly basis until recently when the frequency has been increased to twice a month are made with a cryogenically cooled frost point hygrometer. Although the instrument has undergone a number of changes since its adaptation from an earlier design by John Mastenbrook, the basic principle and calibration scale have remained consistent. An important feature of the Boulder time series is its overlap with a number of satellite, balloon, and airborne measurements that have been made over the past two decades. These include satellite instruments such as SAGE II, HALOE and MLS on UARS, MLS and HRDLS on Aura, ACE-FTS, and MIPAS. Airborne and balloon sensors have included the Lyman á, TDL, and other chilled mirror instruments. A number of these observations have been compared in intercomparison exercises. Here several recent satellite observations from MLS and MIPAS over Boulder are compared with the balloon profiles. The time series of balloon water vapor observations at Boulder has shown a significant increase over the 25+ years of soundings. These increases moderated significantly beginning with the dramatic drop in lower stratospheric water vapor beginning in 2000 that has been noted in the satellite as well as the balloon data. More recently the balloon soundings suggest that these dryer conditions have begun to turnaround. Recent satellite observations over Boulder are investigated to determine if this recent change is confirmed in these data.

Oltmans, S. J.; Rosenlof, K. H.; Hurst, D. F.; Stiller, G. P.; Hofmann, D. J.; Hall, E. G.

2008-12-01

219

Investigation of water vapor motion winds from geostationary satellites  

NASA Technical Reports Server (NTRS)

Water vapor imagery from geostationary satellites has been available for over a decade. These data are used extensively by operational analysts and forecasters, mainly in a qualitative mode (Weldon and Holmes 1991). In addition to qualitative applications, motions deduced in animated water vapor imagery can be used to infer wind fields in cloudless regimes, thereby augmenting the information provided by cloud-drift wind vectors. Early attempts at quantifying the data by tracking features in water vapor imagery met with modest success (Stewart et al. 1985; Hayden and Stewart 1987). More recently, automated techniques have been developed and refined, and have resulted in upper-level wind observations comparable in quality to current operational cloud-tracked winds (Laurent 1993). In a recent study by Velden et al. (1993) it was demonstrated that wind sets derived from Meteosat-3 (M-3) water vapor imagery can provide important environmental wind information in data void areas surrounding tropical cyclones, and can positively impact objective track forecasts. M-3 was repositioned to 75W by the European Space Agency in 1992 in order to provide complete coverage of the Atlantic Ocean. Data from this satellite are being transmitted to the U.S. for operational use. Compared with the current GOES-7 (G-7) satellite (positioned near 112W), the M-3 water vapor channel contains a superior horizontal resolution (5 km vs. 16 km ). In this paper, we examine wind sets derived using automated procedures from both GOES-7 and Meteosat-3 full disk water vapor imagery in order to assess this data as a potentially important source of large-scale wind information. As part of a product demonstration wind sets were produced twice a day at CIMSS during a six-week period in March and April (1994). These data sets are assessed in terms of geographic coverage, statistical accuracy, and meteorological impact through preliminary results of numerical model forecast studies.

Velden, Christopher S.; Nieman, Steven J.; Wanzong, Steven

1994-01-01

220

Strategies for Near Real Time Estimation of Precipitable Water Vapor  

NASA Technical Reports Server (NTRS)

Traditionally used for high precision geodesy, the GPS system has recently emerged as an equally powerful tool in atmospheric studies, in particular, climatology and meteorology. There are several products of GPS-based systems that are of interest to climatologists and meteorologists. One of the most useful is the GPS-based estimate of the amount of Precipitable Water Vapor (PWV) in the troposphere. Water vapor is an important variable in the study of climate changes and atmospheric convection (Yuan et al., 1993), and is of crucial importance for severe weather forecasting and operational numerical weather prediction (Kuo et al., 1993).

Bar-Sever, Yoaz E.

1996-01-01

221

Airborne and spaceborne lidar measurements of water vapor profiles - A sensitivity analysis  

Microsoft Academic Search

This paper presents an evaluation of the random and systematic error sources associated with differential absorption lidar (DIAL) measurements of tropospheric water vapor profiles from airborne and spaceborne platforms. The results of this analysis are used in the development and performance evaluation of the Lidar Atmospheric Sensing Experiment (LASE) H2O DIAL system presently under development at the NASA Langley Research

Syed Ismail; Edward V. Browell

1989-01-01

222

Study of the Impact of Simulated 183 GHZ Water Vapor Retrievals on Numerical Weather Prediction.  

National Technical Information Service (NTIS)

Observing system simulation experiments (OSSEs) are conducted to assess the impact of the Special Sensor Microwave 183 GHz (SSM/T-2) water vapor sounder and the associated SSM/T-1 temperature sounder. Analyzed and forecast meteorological fields are improv...

C. Grassotti J.-F. Louis R. Isaacs R. N. Hoffman T. Nehrkorn

1989-01-01

223

Water Vapor Desorption Characteristics of Honeycomb Type Sorption Element Composed of Organic Sorbent  

NASA Astrophysics Data System (ADS)

This paper describes the water vapor desorption characteristics of honeycomb shape type sorbent element containing new organic sorbent of the bridged complex of sodium polyacrylate. The transient experiments in which the dry air was passed into the honeycomb type sorbent element sorbed water vapor were carried out under various conditions of air velocity, temperature, relative humidity and honeycomb length. The obtained data for desorption process were compared with those for sorption process. Finally, Sherwood number of mass transfer of the organic sorbent for desorption process was derived in terms of Reynolds number, modified Stefan number and non-dimensional honeycomb length.

Inaba, Hideo; Kida, Takahisa; Horibe, Akihiko; Kaneda, Makoto; Okamoto, Tamio; Seo, Jeong-Kyun

224

The Nimbus 7 LIMS (Limb Infrared Monitor of the Stratosphere) water vapor measurements  

NASA Astrophysics Data System (ADS)

Earth orbital instruments, designed to measure the vertical and spatial distribution of atmospheric water vapor is discussed. Specifically, the operation of the Limb Infrared Monitor of the Stratosphere (LIMS) experiment is examined. The LIMS is a six channel limb scanning radiometer that was launched aboard Nimbus 7 in 1978. Profiles of stratospheric and mesospheric temperature, water vapor, and various other constituents were obtained by inverting the LIMS radiance measurements. This same technique was used in 1981 to analyze the data returned from another limb scanning radiometer aboard the Solar Mesosphere Explorer.

Remsberg, Ellis E.; Russell, James M., III

225

The Nimbus 7 LIMS (Limb Infrared Monitor of the Stratosphere) water vapor measurements  

NASA Technical Reports Server (NTRS)

Earth orbital instruments, designed to measure the vertical and spatial distribution of atmospheric water vapor is discussed. Specifically, the operation of the Limb Infrared Monitor of the Stratosphere (LIMS) experiment is examined. The LIMS is a six channel limb scanning radiometer that was launched aboard Nimbus 7 in 1978. Profiles of stratospheric and mesospheric temperature, water vapor, and various other constituents were obtained by inverting the LIMS radiance measurements. This same technique was used in 1981 to analyze the data returned from another limb scanning radiometer aboard the Solar Mesosphere Explorer.

Remsberg, Ellis E.; Russell, James M., III

1988-01-01

226

Modelling of water\\/organic vapor dehydration by glassy polymer membranes  

Microsoft Academic Search

Hydrophilic glassy polymers are suitable membranes for the dehydration of water\\/organic vapor mixtures. Vapor permeation is the predominant process for the dehydration of organic vapors employing glassy polymers. The permeation of vapor mixtures through this type of membrane is usually analyzed in terms of a dual-mode transport model which fails to predict well the separation behavior of a vapor mixture.

A. Salem; A. A. Ghoreyshi

2006-01-01

227

[Study on large-scale regional laser detection methods for water vapor concentration].  

PubMed

Water vapor is an important meteorological parameter in the atmosphere, TDLAS direct absorption technology combined with open-path monitoring was used in order to achieve large-scale regional atmospheric water vapor concentration detection with high sensitivity, high accuracy and fast response, and to correct the remote sensing data. The large-scale regional laser detection system for water vapor was designed and the absorption line of water vapor molecules near 1.27 microm was chosen as the goal line. The system performance was verified in conjunction with a multiple reflection cell, that the system limit sensitivity was 14.803 mmol.mol-1 in optical path of 40 m. The continuous field experiment in 1,420 m optical path at the Yucheng Integrated Experimental Station, CAS was completed with this system which worked stably. Then the measured data was compared with the data of a gas analyzer LI-7500 in eddy correlation observation system at the same site, and the data consistency was good. A new method for water vapor concentration monitoring in the complex field of non-uniform underlying surface was provided. PMID:23705417

He, Ying; Zhang, Yu-Jun; Wang, Li-Ming; You, Kun; Zhou, Yi; Sun, Xiao-Min; Liu, Zhen-Min

2013-03-01

228

Water Mist Experiment  

NASA Technical Reports Server (NTRS)

The Water Mist commercial research program is scheduled to fly an investigation on STS-107 in 2002 in the updated Combustion Module (CM-2), a sophisticated combustion chamber plus diagnostic equipment. The Center for the Commercial Applications of Combustion in Space (CCACS), a NASA Commercial Space Center located at the Colorado School of Mines, is investigating the properties of mist fire suppression in microgravity with Industry Partner Environmental Engineering Concepts. These experiments consist of varying water droplet sizes and water mist concentrations applied to flame fronts of different propane/air mixtures. Observations from these tests will provide valuable information on the change of flame speed in the presence of water mist. Shown here is a flame front propagating through the Mist flame tube during 1-g testing at NASA/Glenn Research Center.

2001-01-01

229

Preliminary Design Program: Vapor Compression Distillation Flight Experiment Program  

NASA Technical Reports Server (NTRS)

This document provides a description of the results of a program to prepare a preliminary design of a flight experiment to demonstrate the function of a Vapor Compression Distillation (VCD) Wastewater Processor (WWP) in microgravity. This report describes the test sequence to be performed and the hardware, control/monitor instrumentation and software designs prepared to perform the defined tests. the purpose of the flight experiment is to significantly reduce the technical and programmatic risks associated with implementing a VCD-based WWP on board the International Space Station Alpha.

Schubert, F. H.; Boyda, R. B.

1995-01-01

230

Water Vapor Tracers as Diagnostics of the Regional Hydrologic Cycle  

NASA Technical Reports Server (NTRS)

Numerous studies suggest that local feedback of evaporation on precipitation, or recycling, is a significant source of water for precipitation. Quantitative results on the exact amount of recycling have been difficult to obtain in view of the inherent limitations of diagnostic recycling calculations. The current study describes a calculation of the amount of local and remote sources of water for precipitation, based on the implementation of passive constituent tracers of water vapor (termed water vapor tracers, WVT) in a general circulation model. In this case, the major limitation on the accuracy of the recycling estimates is the veracity of the numerically simulated hydrological cycle, though we note that this approach can also be implemented within the context of a data assimilation system. In this approach, each WVT is associated with an evaporative source region, and tracks the water until it precipitates from the atmosphere. By assuming that the regional water is well mixed with water from other sources, the physical processes that act on the WVT are determined in proportion to those that act on the model's prognostic water vapor. In this way, the local and remote sources of water for precipitation can be computed within the model simulation, and can be validated against the model's prognostic water vapor. Furthermore, estimates of precipitation recycling can be compared with bulk diagnostic approaches. As a demonstration of the method, the regional hydrologic cycles for North America and India are evaluated for six summers (June, July and August) of model simulation. More than 50% of the precipitation in the Midwestern United States came from continental regional tracers, and the local source was the largest of the regional tracers (14%). The Gulf of Mexico and Atlantic 2 regions contributed 18% of the water for Midwestern precipitation, but further analysis suggests that the greater region of the Tropical Atlantic Ocean may also contribute significantly. In general, most North American land regions showed a positive correlation between evaporation and recycling ratio (except the Southeast United States) and negative correlations of recycling ratio with precipitation and moisture transport (except the Southwestern United States). The Midwestern local source is positively correlated with local evaporation, but it is not correlated with water vapor transport. This is contrary to bulk diagnostic estimates of precipitation recycling. In India, the local source of precipitation is a small percentage of the precipitation owing to the dominance of the atmospheric transport of oceanic water. The southern Indian Ocean provides a key source of water for both the Indian continent and the Sahelian region.

Bosilovich, Michael G.; Schubert, Siegfried; Einaudi, Franco (Technical Monitor)

2001-01-01

231

Cassini/CIRS Observations of Water Vapor in Saturn's Stratosphere  

NASA Technical Reports Server (NTRS)

The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft has obtained numerous spectra of Saturn at varying spectral and spatial resolutions since Saturn Orbit Insertion in 2004. Emission lines due to water vapor in Saturn's stratosphere were first detected using whole-disk observations from the Infrared Space Observatory (Feuchtgruber et al 1997) and subsequently confirmed by the Submillimeter Wave Astronomy Satellite (Rergin et al 2000). CIRS has detected water and the data permit the retrieval of the latitudinal variation of water on Saturn. Emission lines of H2O on Saturn are very weak in the CIRS data. Thus. large spectral averages as well as improvements in calibration are necessary to detect water vapor. Zonally averaged nadir spectra were produced every 10 degrees of latitude. Stratospheric temperatures in the 0.5 - 5.0 mbar range were obtained by inverting spectra of CH4 in the v4 band centered at 1304 cm(exp -1). The origin of water vapor is believed to be from the ablation of micrometeorites containing water ice, followed by photochemistry. This external source of oxygen originates either from the Saturn system (from the rings or perhaps from Enceladus) or from the interplanetary medium. Connerney (1986) proposed a mechanism to transport water from the inner edge of the B-ring along magnetic field lines to specific latitudes (50N and 44S) on Saturn. Prange et al (2006) interpreted a minimum in the abundance of acetylene from ultraviolet spectra near 41S on Saturn as possibly due to an enhanced influx of water. Existing CIRS far-IR spectra are at relatively low spatial resolution, but observations at closer range planned for the extended mission will be able to test the "ring rain" mechanism by searching for localized water vapor enhancement at midlatitudes.

Bjoraker, G. L.; Achterberg, R. K.; Simon-Miller, A. A.; Carlson, R. C.; Jennings, D. E.

2008-01-01

232

Microstructure and water vapor transport properties of temperature sensitive polyurethanes  

Microsoft Academic Search

Temperature sensitive polyurethane (TS-PU) is one novel type of smart polymers. The water vapor permeability (WVP) of its membrane could undergo a significant increase as temperature increases within a predetermined temperature range. Such smart property enables this material to have a broad range of potential applications to textile industry, medicine, environmental fields and so on. However, based on the literature

Xuemei Ding

2003-01-01

233

DETERMINING HOW VAPOR PHASE MTBE REACHES GROUND WATER  

EPA Science Inventory

EPA Region 2 and ORD have funded a RARE project for FY 2005/2006 to evaluate the prospects that MTBE (and other fuel components) in vapors that escape from an underground storage tank (UST) can find its way to ground water produced by monitoring wells at a gasoline filling statio...

234

Third Virial Coefficient for Air-Water Vapor Mixtures.  

National Technical Information Service (NTIS)

The third interaction virial coefficient Caww for air-water vapor mixtures is estimated in the temperature range 0 to 100C, by means of an approximate method based on molecular association. The results are believed accurate to within a factor of two. The ...

R. W. Hyland E. A. Mason

1967-01-01

235

Water vapor plasma technology for biomass conversion to synthetic gas  

Microsoft Academic Search

This study presents the results of experimental investigation on the development of water vapor plasma technology for conversion of biomass and destruction of hazardous substances. Similar plasma technology is also foreseen for the synthesis of micro- and nanostructured catalytic coatings for wide range of applications.An experimental DC plasma torch with button type hot cathode and step formed copper anode, operating

V. Grigaitien?; V. Snapkauskien?; P. Valatkevi?ius; A. Tamoši?nas; V. Valin?ius

2011-01-01

236

Oxidation and Volatilization of Silica-Formers in Water Vapor  

NASA Technical Reports Server (NTRS)

At high temperatures SiC and Si3N4 react with water vapor to form a silica scale. Silica scales also react with water vapor to form a volatile Si(OH)4 species. These simultaneous reactions, one forming silica and the other removing silica, are described by paralinear kinetics. A steady state, in which these reactions occur at the same rate, is eventually achieved, After steady state is achieved, the oxide found on the surface is a constant thickness and recession of the underlying material occurs at a linear rate. The steady state oxide thickness, the time to achieve steady state, and the steady state recession rate can all be described in terms of the rate constants for the oxidation and volatilization reactions. In addition, the oxide thickness, the time to achieve steady state, and the recession rate can also be determined from parameters that describe a water vapor-containing environment. Accordingly, maps have been developed to show these steady state conditions as a function of reaction rate constants, pressure, and gas velocity. These maps can be used to predict the behavior of silica formers in water-vapor containing environments such as combustion environments. Finally, these maps are used to explore the limits of the paralinear oxidation model for SiC and Si3N4

Opila, E. J.; Gray, Hugh R. (Technical Monitor)

2002-01-01

237

Advances in Raman Lidar Measurements of Water Vapor  

NASA Technical Reports Server (NTRS)

Recent technology upgrades to the NASA/GSFC Scanning Raman Lidar have permitted significant improvements in the daytime and nighttime measurement of water vapor using Raman lidar. Numerical simulation has been used to study the temperature sensitivity of the narrow spectral band measurements presented here.

Whiteman, D. N.; Evans, K.; Demoz, B.; DiGirolamo, P.; Mielke, B.; Stein, B.; Goldsmith, J. E. M.; Tooman, T.; Turner, D.; Starr, David OC. (Technical Monitor)

2002-01-01

238

Variations in water vapor continuum radiative transfer with atmospheric conditions  

NASA Astrophysics Data System (ADS)

A newly formulated empirical water vapor continuum (the "BPS continuum") is employed, in conjunction with ERA-40 data, to advance the understanding of how variations in the water vapor profile can alter the impact of the continuum on the Earth's clear-sky radiation budget. Three metrics are investigated: outgoing longwave radiation (OLR), Longwave surface downwelling radiation (SDR) and shortwave absorption (SWA). We have also performed a detailed geographical analysis on the impact of the BPS continuum upon these metrics and compared the results to those predicted by the commonly used MT CKD model. The globally averaged differences in these metrics when calculated with MT CKD 2.5 versus BPS were found to be 0.1%, 0.4% and 0.8% for OLR, SDR and SWA respectively. Furthermore, the impact of uncertainty upon these calculations is explored using the uncertainty estimates of the BPS model. The radiative response of the continuum to global changes in atmospheric temperature and water vapor content are also investigated. For the latter, the continuum accounts for up to 35% of the change in OLR and 65% of the change in SDR, brought about by an increase in water vapor in the tropics.

Paynter, D.; Ramaswamy, V.

2012-08-01

239

Development of Elastomers Having Low Water-Vapor Transmission Rate.  

National Technical Information Service (NTIS)

The effect of various types of fillers on the water-vapor transmission rate (WVTR) of vulcanizates of ethylene propylene terpolymer rubber was determined. Carbon-black and most nonblack fillers produced only a small reduction in the WVTR, whereas platelik...

J. A. Williams

1971-01-01

240

Interactions between aerosol, water vapor, and solar radiation  

Microsoft Academic Search

A quantitative understanding of how clouds, aerosols and atmospheric gases affect the solar radiation absorbed by earth's climate systems is still largely unknown. This dissertation makes calibrated and precise (<1%) measurements of broadband and spectral solar radiation, and integrates these measurements with state-of-the-art radiative transfer models to clarify the roles of water vapor and aerosols in the solar heating of

William Christopher Conant

2000-01-01

241

Development of a High Stability Water Vapor Radiometer  

NASA Technical Reports Server (NTRS)

Preliminary design details and laboratory test results of a microwave radiometer operating near the 22.2 GHz water vapor resonance line are presented. Radiometric stability to 10mK for several hours is the design goal. Early indications are that these goals are being met in the prototype system.

Tanner, Alan B.

1997-01-01

242

Columnar water vapor retrievals from multifilter rotating shadowband radiometer data  

Microsoft Academic Search

The multifilter rotating shadowband radiometer (MFRSR) measures direct and diffuse irradiances in the visible and near-infrared spectral range. In addition to characteristics of atmospheric aerosols, MFRSR data also allow retrieval of precipitable water vapor (PWV) column amounts, which are determined from the direct normal irradiances in the 940-nm spectral channel. The HITRAN 2004 spectral database was used in our retrievals

Mikhail D. Alexandrov; Beat Schmid; David D. Turner; Brian Cairns; Valdar Oinas; Andrew A. Lacis; Seth I. Gutman; Ed R. Westwater; Alexander Smirnov; James Eilers

2009-01-01

243

Thermodynamic properties of water + normal alcohols and vapor-liquid equilibria for binary systems of methanol or 2-propanol with water  

Microsoft Academic Search

Experiments have been carried out to determine densities and refractive indices of binary and ternary mixtures of water with normal alcohols (methanol and n-butanol) at 293.15 K. Also, vapor-liquid equilibrium data have been measured for binary systems of methanol-water and 2-propanol-water at atmospheric pressure, from which the excess Gibbs free energy was computed for both systems. The experimental vapor-liquid equilibrium

Brahim Khalfaoui; Abdessalem H. Meniai; Rafael Borja

1997-01-01

244

a Study of Gnss Water Vapor Reconstruction Parameters  

NASA Astrophysics Data System (ADS)

GNSS (Global Navigation Satellite Systems) observations are nowadays a well-established tool to measure the water vapor content in the atmosphere. This gas plays a major role in many processes concerning physics, thermodynamics and dynamics of the atmosphere. The knowledge of the spatial and temporal distribution of water vapor in the lower atmosphere (troposphere) is crucial for accurate quantitative prediction of precipitation and better understanding of many atmospheric processes like deep convective events. Major advantages of the use of GNSS observations are all-weather system, continuous unattended operation, high temporal resolution and an ever-increasing number of stations. The present work focuses on the study of the geometry and dynamics of moist convection, shallow and deep, through the use of 4D images of the atmosphere water vapor field, obtained from high-density GPS networks (i.e. tomographic inversion). For this, the SWART (SEGAL GNSS WAter Vapor ReconsTruction Image Software), a software package for GNSS water vapor reconstruction, has been developed. This package currently consists of four C++ programs. The C++ programs gather the necessary information to calculate the slant delays and to generate a file with the reconstructed image. The output consists in 2D slices of the 3D water vapor image in latitude, longitude or altitude. SWART is based on LOFTT_K (LOgiciel Français de Tomographie Troposphérique version Kalman) (Champollion 2005). We present the results of the comparison with LOFTT_K to validate SWART together with several tests covering diverse grid sizes and different number of receivers for the same water vapor image reconstruction. It is also analyzed the importance of the initial values for the image reconstruction. All these tests were realized with synthetic data, except for the grid area, which is from Marseilles, France. Finally, we present the current status of the analysis being carrying out for a dense network in Belem, Brazil which data was acquired in the framework of the project CHUVA during September, 2011. This work is being carried out in the framework of the SMOG (PTDC/CTE-ATM/119922/2010) project funded by FCT. References: Champollion C., 2005: Quantification de la vapeur d'eau troposphérique par GPS (modèle 2D et tomographie 3D) - Application aux précipitations intenses. Thèse de doctorat, Laboratoire de Dynamique de la Lithosphère (Université Montpellier II).

Sá, A. G.; Bento, F.; Crocker, P.; Fernandes, R. M.; Adams, D. K.; Miranda, P. M.

2013-12-01

245

The interannual variability of atmospheric water vapor on Mars  

NASA Technical Reports Server (NTRS)

The acquisition of several north-south scans during the Survey/Completion Mission by the Mars Atmospheric Water Detector (MAWD) onboard Viking Orbiter 1 make it possible to compare water vapor column abundance during northern spring and early summer seasons from three successive Mars years. All three years exhibit very similar seasonal trends. Differences between years tend to be localized, and not regional, with maximum differences between years occurring in the same general areas that the day-to-day variability of water vapor as observed by MAWD is large. It is suggested that the observed year-to-year differences are also artifacts of clouds in the MAWD field of view and that there is remarkably little difference in the water cycle during northern spring and early summer, despite very different dust storm episodes during the preceding three years.

Zurek, Richard W.

1988-01-01

246

The interaction of the theophylline metastable phase with water vapor  

NASA Astrophysics Data System (ADS)

The conditions of hydration of the stable and metastable theophylline phases were determined. Two-phase metastable phase/monohydrate and stable phase/monohydrate equilibrium pressures were measured at 25, 30, and 35°C. The metastable phase began to react with water vapor at lower relative humidities than the stable phase. Processes that occurred with the metastable and stable theophylline phases over various water pressure ranges were considered. The metastable phase exhibited an unusual behavior at 25°C and relative humidity 47%. At constant water vapor pressure and temperature, theophylline was initially hydrated and then lost water and again became anhydrous. Two consecutive processes occurred in the system, the formation of theophylline monohydrate from the metastable phase and its decomposition to the stable phase. The ratio between the rates of these processes determined the content of the monohydrate at the given time moment.

Matvienko, A. A.; Boldyrev, V. V.; Sidel'Nikov, A. A.; Chizhik, S. A.

2008-07-01

247

Highly stable indomethacin glasses resist uptake of water vapor.  

PubMed

Mass uptake of water vapor was measured as a function of relative humidity for indomethacin glasses prepared using physical vapor deposition at different substrate temperatures. Highly stable glasses were produced on substrates at 265 K (0.84Tg) by depositing at 0.2 nm/s while samples similar to melt-cooled glasses were produced at 315 K and 5 nm/s. Samples deposited at 315 K absorb approximately the same amount of water as glasses prepared by supercooling the melt while stable glasses absorb a factor of 5 less water. Unexpectedly, the diffusion of water in the stable glass samples is 5-10 times faster than in the glass prepared by cooling the liquid. PMID:19183039

Dawson, Kevin J; Kearns, Kenneth L; Ediger, M D; Sacchetti, Mark J; Zografi, George D

2009-02-26

248

Crystal growth from the vapor phase experiment MA-085  

NASA Technical Reports Server (NTRS)

Three vapor transport experiments on multicomponent systems were performed during the Apollo Soyuz mission to determine the effects of microgravity forces on crystal morphology and mass transport rates. The mixed systems used germanium selenide, tellurium, germanium tetraiodide (transport agent), germanium monosulfide, germanium tetrachloride (transport agent), and argon (inert atmosphere). The materials were enclosed in evacuated sealed ampoules of fused silica and were transported in a temperature gradient of the multipurpose electric furnace onboard the Apollo Soyuz spacecraft. Preliminary evaluation of 2 systems shows improved quality of space grown crystals in terms of growth morphology and bulk perfection. This conclusion is based on a direct comparison of space grown and ground based crystals by means of X-ray diffraction, microscopic, and chemical etching techniques. The observation of greater mass transport rates than predicted for a microgravity environment by existing vapor transport models indicates the existence of nongravity caused transport effects in a reactive solid/gas phase system.

Wiedemeir, H.; Sadeek, H.; Klaessig, F. C.; Norek, M.

1976-01-01

249

Coupling between plant leaf water and atmospheric vapor: insights from isotopic analyses  

NASA Astrophysics Data System (ADS)

We measured stable isotopic composition of leaf water and atmospheric water vapor in an old growth forest in the Pacific Northwest of U.S.A. in the summer of 2011. A LGR cavity-enhanced absorption spectroscopy analyzer was used to measure hourly 18O/16O and 2H/1H ratios of atmospheric water vapor (?18Ov and ?Dv) at three canopy heights (1m, 10m and 60m aboveground). Modeling studies show that transpiration plays an important role in controlling ?18Ov and ?Dv variation in this forest. Here we use deuterium excess (d = ?D - 8 x ?18O), an isotopic tracer independent of the equilibrium process, to investigate H2O molecular diffusion and exchange between leaf water and atmospheric water vapor. We observed a robust diel pattern in the d values of atmospheric vapor (dv); its daily values typically fluctuate from -20‰ at night to +20‰ at midday. We found a strong correlation between dv and relative humidity (h). In under-saturated conditions, dv and h follow a hyperbolic relationship where values of dv increase asymptotically as h decreases. To investigate how h influences the H2O molecular exchange between leaf water and atmospheric water vapor, bulk leaf waters of dominant understory plant species were sampled every two hours for three consecutive days. Stable isotope analysis of leaf water was used to validate Craig-Gordon model calculations. Model comparisons suggest that retrodiffusion of atmospheric H2O molecules into leaf intercellular space must have intensified beginning in the mid-afternoon and continue throughout the night to counter-balance the evaporative isotopic enrichment in leaf water, which typically occurs after sunrise and peaks at midday. H2O molecular exchange occurring between an evaporating surface and water vapor limits the extent of evaporative enrichment of a finite water reservoir. This idea has been illustrated by laboratory experiments but to our best knowledge, never has been tested in field conditions. Our results demonstrate a strong coupling between leaf water and atmospheric water vapor, which have implications on the interpretation of isotopic variation including terrestrial H2O and CO2 gas exchange.

Rambo, J. P.; Lai, C.

2012-12-01

250

Proton magnetic relaxation in aromatic polyamides during water vapor sorption  

NASA Astrophysics Data System (ADS)

The state of the components in the aromatic polyamide-water system was studied by NMR and sorption. A comparative analysis of spin-lattice and spin-spin relaxation in aromatic para-polyamide ( para-aramid) technical fibers Rusar, Kevlar, and Technora was performed depending on the sorption value. The NMR results correlated with the supramolecular structure of polymers and quasi-chemical equation parameters for water vapor sorption.

Smotrina, T. V.; Chulkova, Yu. S.; Karasev, D. V.; Lebedeva, N. P.; Perepelkin, K. E.; Grebennikov, S. F.

2009-07-01

251

Water vapor sorption in naphthalenic sulfonated polyimide membranes  

Microsoft Academic Search

The water vapor uptake of sulfonated polyimides (SP) was investigated by electronic microbalance (IGA, Hiden) from 15 to 55°C. The sigmo??dal isotherms obtained (BET II type) are considered as dual sorption (concave part) plus clustering (convex part) and are fitted with good agreement by Park’s equation. Zimm–Lundberg’s method is used to study the clustering process of water molecules: limit clustering

Virginie Detallante; Dominique Langevin; Corinne Chappey; Michel Métayer; Régis Mercier; Michel Pinéri

2001-01-01

252

Cassini/CIRS Observations of Water Vapor in Saturn's Stratosphere  

NASA Technical Reports Server (NTRS)

The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft has obtained numerous spectra of Saturn at varying spectral and spatial resolutions since Saturn Orbit Insertion in 2001. Emission lines due to water vapor in Saturn's stratosphere were first detected using whole-disk observations from the Infrared Space Observatory [1] and subsequently confirmed by the Submillimeter Wave Astronomy Satellite [2], CIRS has detected water and the data permit the retrieval of the latitudinal variation of water on Saturn. Emission lines of H2O on Saturn are very weak in the CIRS data. Thus, large spectral averages as well as improvements in calibration are necessary to detect water vapor. long integrations at the full 0.5/cm spectral resolution were performed at targeted latitudes on Saturn. High emission angles were chosen to enhance stratospheric emission. Over the course of the prime and extended mission a set of observations has been built up spaced roughly every 10 degrees of latitude. Stratospheric temperatures in the 0.5 - 5.0 mbar range were obtained by inverting spectra of CH4 in the v'4 band centered at 1501/cm. The origin of water vapor is believed to be from the ablation of micrometeorites containing eater ice, followed by photochemistry. This external source of oxygen originates either from the Saturn system (from the rings or perhaps from Enceladus) or from the interplanetary medium. Connerney [3] proposed a mechanism to transport water from the inner edge of the B-ring along magnetic field lines to specific latitudes (50N and 44S) on Saturn. Prange et al [4] interpreted a minimum in the abundance of acetylene from ultraviolet spectra gear 41S on Saturn as possibly due to an enhanced influx of water. We will be able to test the "ring rain" mechanism by searching, for localized water vapor enhancement at mid-latitudes. Our results may be used to constrain photochemical models of Saturn's stratosphere [5].

Bjoraker, Gordon; Achterberg, R. K.; Simon-Miller, A. A.; Jennings, D. E.

2010-01-01

253

Fixation of nitrogen in the presence of water vapor  

DOEpatents

A process for the fixation of nitrogen is disclosed which comprises combining a mixture of nitrogen, oxygen, metal oxide and water vapor, initially heating the combination to initiate a reaction which forms nitrate, but at a temperature and pressure range below the dissociation pressure of the nitrate. With or without the water component, the yield of fixed nitrogen is increased by the use of a Linde Molecular Sieve Catalyst.

Harteck, Paul (Santa Barbara, CA)

1984-01-01

254

Alexandrite laser transmitter development for airborne water vapor DIAL measurements  

NASA Technical Reports Server (NTRS)

In the DIAL technique, the water vapor concentration profile is determined by analyzing the lidar backscatter signals for laser wavelengths tuned 'on' and 'off' a water vapor absorption line. Desired characteristics of the on-line transmitted laser beam include: pulse energy greater than or equal to 100 mJ, high-resolution tuning capability (uncertainty less than 0.25 pm), good spectral stability (jitter less than 0.5 pm about the mean), and high spectral purity (greater than 99 percent). The off-line laser is generally detuned less than 100 pm away from the water vapor line. Its spectral requirements are much less stringent. In our past research, we developed and demonstrated the airborne DIAL technique for water vapor measurements in the 720-nm spectral region using a system based on an alexandrite laser as the transmitter for the on-line wavelength and a Nd:YAG laser-pumped dye laser for the off-line wavelength. This off-line laser has been replaced by a second alexandrite laser. Diode lasers are used to injection seed both lasers for frequency and linewidth control. This eliminates the need for the two intracavity etalons utilized in our previous alexandrite laser and thereby greatly reduces the risk of optical damage. Consequently, the transmitted pulse energy can be substantially increased, resulting in greater measurement range, higher data density, and increased measurement precision. In this paper, we describe the diode injection seed source, the two alexandrite lasers, and the device used to line lock the on-line seed source to the water vapor absorption feature.

Chyba, Thomas H.; Ponsardin, Patrick; Higdon, Noah S.; DeYoung, Russell J.; Browell, Edward V.

1995-01-01

255

New VLA Observations of Mars Atmospheric Water Vapor  

NASA Astrophysics Data System (ADS)

The presence of water vapor in the atmosphere of Mars is becoming increasingly recognized as a key element of that planet's climate. Previous studies have characterized latitudinal and seasonal variations in the quantity and transport of water vapor, but detailed information regarding its distribution as a function of altitude, and how that changes with season, is still lacking. One method of determining the vertical distribution is via spectroscopic observations of the 1.35-cm rotational transition (Clancy et al. 1992, Icarus, 100, 48; Clancy et al. 1996, Icarus, 122, 36). Shortly after the 2003 opposition, such observations were conducted with the Very Large Array (VLA). The observations were taken on four dates, in two high resolution configurations of the VLA. These observations provide a good combination of sensitivity and spatial resolution for mapping the martian atmospheric water vapor. The shape of the line can be used to infer a vertical profile, and spatial variations around the limb give information on the latitudinal and local time distributions of water vapor. The season on Mars during these observations (Ls=265-285, around southern summer solstice) is of particular interest, as the water vapor supplied to the atmosphere from the south polar cap at that time appears to vary significantly from year to year. These observations can be compared to a number of contemporaneous observations from other instruments, including the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES), the Submillimeter Wave Astronomy Satellite (SWAS) and the Submillimeter Array (SMA). Results from the preliminary analysis of these new data will be presented and implications discussed.

Butler, B. J.; Johnston, J. G.; Clancy, R. T.; Gurwell, M. A.

2005-08-01

256

Columnar water vapor retrievals from multifilter rotating shadowband radiometer data  

SciTech Connect

The Multi-Filter Rotating Shadowband Radiometer (MFRSR) measures direct and diffuse irradiances in the visible and near IR spectral range. In addition to characteristics of atmospheric aerosols, MFRSR data also allow retrieval of precipitable water vapor (PWV) column amounts, which are determined from the direct normal irradiances in the 940 nm spectral channel. The HITRAN 2004 spectral database was used in our retrievals to model the water vapor absorption. We present a detailed error analysis describing the influence of uncertainties in instrument calibration and spectral response, as well as those in available spectral databases, on the retrieval results. The results of our PWV retrievals from the Southern Great Plains (SGP) site operated by the DOE Atmospheric Radiation Measurement (ARM) Program were compared with correlative standard measurements by Microwave Radiometers (MWRs) and a Global Positioning System (GPS) water vapor sensor, as well as with retrievals from other solar radiometers (AERONET’s CIMEL, AATS-6). Some of these data are routinely available at the SGP’s Central Facility, however, we also used measurements from a wider array of instrumentation deployed at this site during the Water Vapor Intensive Observation Period (WVIOP2000) in September – October 2000. The WVIOP data show better agreement between different solar radiometers or between different microwave radiometers (both groups showing relative biases within 4%) than between these two groups of instruments, with MWRs values being consistently higher (up to 14%) than those from solar instruments. We also demonstrate the feasibility of using MFRSR network data for creation of 2D datasets comparable with the MODIS satellite water vapor product.

Alexandrov, Mikhail; Schmid, Beat; Turner, David D.; Cairns, Brian; Oinas, Valdar; Lacis, Andrew A.; Gutman, S.; Westwater, Ed R.; Smirnov, A.; Eilers, J.

2009-01-26

257

Columnar water vapor retrievals from multifilter rotating shadowband radiometer data  

NASA Astrophysics Data System (ADS)

The multifilter rotating shadowband radiometer (MFRSR) measures direct and diffuse irradiances in the visible and near-infrared spectral range. In addition to characteristics of atmospheric aerosols, MFRSR data also allow retrieval of precipitable water vapor (PWV) column amounts, which are determined from the direct normal irradiances in the 940-nm spectral channel. The HITRAN 2004 spectral database was used in our retrievals to model the water vapor absorption. We present a detailed error analysis describing the influence of uncertainties in instrument calibration and spectral response, as well as those in available spectral databases, on the retrieval results. The results of our PWV retrievals from the Southern Great Plains (SGP) site operated by the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program were compared with correlative standard measurements by microwave radiometers (MWRs) and a global positioning system (GPS) water vapor sensor, as well as with retrievals from other solar radiometers (AERONET's CIMEL, AATS-6). Some of these data are routinely available at the SGP's Central Facility; however, we also used measurements from a wider array of instrumentations deployed at this site during the water vapor intensive observation period (WVIOP2000) in September-October 2000. The WVIOP data show better agreement between different solar radiometers or between different microwave radiometers (both groups showing relative biases within 4%) than between these two groups of instruments, with MWR values being consistently higher (up to 14%) than those from solar instruments (especially in the large PWV column amount range). We also demonstrate the feasibility of using MFRSR network data for creation of 2D data sets comparable with that of the MODIS satellite water vapor product.

Alexandrov, Mikhail D.; Schmid, Beat; Turner, David D.; Cairns, Brian; Oinas, Valdar; Lacis, Andrew A.; Gutman, Seth I.; Westwater, Ed R.; Smirnov, Alexander; Eilers, James

2009-01-01

258

Water vapor and cloud water measurements over Darwin during the STEP 1987 tropical mission  

SciTech Connect

The authors report results of total water, and water vapor measurements made in the upper troposphere and stratosphere during the Stratosphere-Troposphere Exchange Project (STEP) Tropical mission over Darwin, Australia. Measurements were made from an ER-2 aircraft by lyman-[alpha] hygrometers. The average lower stratosphere water vapor was 2.4 parts per million by volume (ppmv), at a potential temperature of 375 K. This level is lower than the 3 to 4 ppmv water vapor level typical of the stratosphere.

Kelly, K.K.; Proffitt, M.H. (NOAA Aeronomy Lab., Boulder, CO (United States)); Chan, K.R.; Loewenstein, M.; Podolske, J.R. (NASA Ames Research Center, Moffett Field, CA (United States)); Strahan, S.E. (Princeton Univ., NJ (United States)); Wilson, J.C. (Univ. of Denver, CO (United States)); Kley, D. (Institut fuer Chemie, Forschungszentrum Julich (Germany))

1993-05-20

259

Microwave and Millimeter-Wave Radiometric Studies of Temperature, Water Vapor and Clouds  

SciTech Connect

The importance of accurate measurements of column amounts of water vapor and cloud liquid has been well documented by scientists within the Atmospheric Radiation Measurement (ARM) Program. At the North Slope of Alaska (NSA), both microwave radiometers (MWR) and the MWRProfiler (MWRP), been used operationally by ARM for passive retrievals of the quantities: Precipitable Water Vapor (PWV) and Liquid Water Path (LWP). However, it has been convincingly shown that these instruments are inadequate to measure low amounts of PWV and LWP. In the case of water vapor, this is especially important during the Arctic winter, when PWV is frequently less than 2 mm. For low amounts of LWP (< 50 g/m{sup 2}), the MWR and MWRP retrievals have an accuracy that is also not acceptable. To address some of these needs, in March-April 2004, NOAA and ARM conducted the NSA Arctic Winter Radiometric Experiment - Water Vapor Intensive Operational Period at the ARM NSA/Adjacent Arctic Ocean (NSA/AAO) site. After this experiment, the radiometer group at NOAA moved to the Center for Environmental Technology (CET) of the Department of Electrical and Computer Engineering of the University of Colorado at Boulder. During this 2004 experiment, a total of 220 radiosondes were launched, and radiometric data from 22.235 to 380 GHz were obtained. Primary instruments included the ARM MWR and MWRP, a Global Positioning System (GPS), as well as the CET Ground-based Scanning Radiometer (GSR). We have analyzed data from these instruments to answer several questions of importance to ARM, including: (a) techniques for improved water vapor measurements; (b) improved calibration techniques during cloudy conditions; (c) the spectral response of radiometers to a variety of conditions: clear, liquid, ice, and mixed phase clouds; and (d) forward modeling of microwave and millimeter wave brightness temperatures from 22 to 380 GHz. Many of these results have been published in the open literature. During the third year of this contract, we participated in another ARM-sponsored experiment at the NSA during February-March 2007. This experiment is called the Radiative Heating in Underexplored Bands Campaign (RHUBC) and the GSR was operated successfully for the duration of the campaign. One of the principal goals of the experiment was to provide retrievals of water vapor during PWV amounts less than 2 mm and to compare GSR data with ARM radiometers and radiosondes. A secondary goal was to compare the radiometric response of the microwave and millimeter wavelength radiometers to water and ice clouds. In this final report, we will include the separate progress reports for each of the three years of the project and follow with a section on major accomplishments of the project.

Westwater, Edgeworth

2011-05-06

260

Creating water vapor barrier coatings from hydrophilic components.  

PubMed

The preparation of water vapor barrier coatings composed of polyelectrolyte/clay multilayers using the layer-by-layer technique is reported. The suitability of different synthetic and renewable polyelectrolytes for the preparation of barrier coatings in combination with montmorillonite (MMT) platelets as well as the influence of the ionic strength and the number of bilayers on the coating performance was investigated. Highly hydrophilic and permeable cellulose films were used as substrate for determining the influence of the coatings on the water vapor transmission rate (WVTR). Improved barrier properties were realized by the use of polyethylene imine (PEI) or 2-hydroxy-3-trimethylammonium propyl chloride starch (HPMA starch) in combination with MMT. After the application of only 5 bilayers of PEI and MMT (thickness ?40 nm) on each side of the cellulose film, the WVTR was significantly reduced. By the deposition of 40 PEI/MMT bilayers, the WVTR transmission rate was reduced by 68%. However, HPMA starch containing coatings led to vapor transmission reduction of up to 32% at the same number of coating steps. A strong correlation between the barrier properties of the coatings and the layer thickness was observed. The barrier properties of the coatings could be increased using higher ionic strengths. These results represent unprecedented water vapor barrier properties for coatings prepared from hydrophilic materials. PMID:22646312

Findenig, Gerald; Leimgruber, Simon; Kargl, Rupert; Spirk, Stefan; Stana-Kleinschek, Karin; Ribitsch, Volker

2012-06-27

261

Water vapor transport in structurally varied polyurethans  

Microsoft Academic Search

A study has been made on four chain-extended polyurethan (PU) elastomers differing only in the nature of the flexible segment, namely, poly(butylene adipate) (PBA), poly(tetramethvlene oxide) (PTMO), poly(propylene oxide) (PPO), and poly(ethylene oxide) (PEO). The saturation water concentration increases from 1.6 to 3% in the first three samples and jumps to 113% in PEO-PU. The flux normalized to 1 mil

N. S. Schneider; L. V. Dusablon; E. W. Snell; R. A. Prosser

1969-01-01

262

Raman Lidar Observations from the ARM Site in Darwin, Australia: A Water Vapor and Aerosol Climatology  

NASA Astrophysics Data System (ADS)

The U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Tropical Western Pacific (TWP) site in Darwin, Australia, collects data over a range of different synoptic regimes in the tropics. Funding from the American Recovery and Reinvestment Act enabled the installation of a new Raman Lidar (RL) at the ARM TWP site in Darwin, Australia. It is the only operational RL in the tropics and the only active remote sensing instrument capable of providing simultaneous measurements of water vapor, clouds, and aerosols at the Darwin site. Thus, it provides important climatological information for better characterization of atmospheric conditions around the TWP region. This study uses 18 months of data from the RL to develop an aerosol and water vapor climatology in the Darwin region. Darwin experiences three distinct climate patterns annually, comprising of 1) a dry continental regime, 2) a wet monsoon season, and 3) a transition period between the dry and wet seasons. The RL observations were separated into different synoptic classes using the technique developed by Evans et al. (2012), and the mean and standard deviation profiles of water vapor mixing ratio and aerosol properties during these three distinct climate regimes will be presented. The median water vapor mixing ratio for the three Darwin climate regimes is shown in figure 1. The lower panel shows the interquartile spread in mixing ratio between the 75th and 25th percentile. Aerosol climatology and comparison of RL derived water vapor mixing ratio profiles with profiles derived from radiosondes will be presented at the conference. Diurnal differences in the distribution of water vapor and aerosols will also be shown. Figure 1: The top panel shows the median RL mixing ratio profiles for the three climate regimes in Darwin (1-dry, 2-transition, 3- wet/monsoon). The bottom panel shows the mixing ratio interquartile spread for the three states. N denotes the number of profiles for each state.

Mishra, S.; Turner, D. D.; Newsom, R. K.; Ferrare, R. A.; Goldsmith, J. E.

2013-12-01

263

Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds  

SciTech Connect

The 'Evaluating Global Aerosol Models and Aerosol and Water Vapor Properties Near Clouds' project focused extensively on the analysis and utilization of water vapor and aerosol profiles derived from the ARM Raman lidar at the Southern Great Plains ARM site. A wide range of different tasks were performed during this project, all of which improved quality of the data products derived from the lidar or advanced the understanding of atmospheric processes over the site. These activities included: upgrading the Raman lidar to improve its sensitivity; participating in field experiments to validate the lidar aerosol and water vapor retrievals; using the lidar aerosol profiles to evaluate the accuracy of the vertical distribution of aerosols in global aerosol model simulations; examining the correlation between relative humidity and aerosol extinction, and how these change, due to horizontal distance away from cumulus clouds; inferring boundary layer turbulence structure in convective boundary layers from the high-time-resolution lidar water vapor measurements; retrieving cumulus entrainment rates in boundary layer cumulus clouds; and participating in a field experiment that provided data to help validate both the entrainment rate retrievals and the turbulent profiles derived from lidar observations.

Turner, David, D.; Ferrare, Richard, A.

2011-07-06

264

Alumina Volatility in Water Vapor at Elevated Temperatures  

NASA Technical Reports Server (NTRS)

The volatility of alumina in high temperature water vapor was determined by a weight loss technique. Sapphire coupons were exposed at temperatures between 1250 and 1500 C, water partial pressures between 0.15 and 0.68 atm in oxygen, total pressure of 1 atm, and flowing gas velocities of 4.4 cm/s. The pressure dependence of sapphire volatility was consistent with AI(OH)3(g) formation. The enthalpy of reaction to form Al(OH)3(g) from sapphire and water vapor was determined to be 210 +/- 20 kJ/mol, comparing favorably to other studies. Microstructural examination of tested sapphire coupons revealed surface etching features consistent with a volatilization process.

Opila, Elizabeth J.; Myers, Dwight L.

2003-01-01

265

Does convectively-detrained cloud ice enhance water vapor feedback?  

NASA Astrophysics Data System (ADS)

We demonstrate that coupled Global Climate Models (GCMs) can reproduce observed correlations among ice water path (IWP), upper tropospheric water vapor (UTWV), and sea surface temperature (SST), and that the presence/strength of this correlation has no direct bearing on the strength of water vapor feedback in the model. The models can accurately reproduce a strong positive correlation between IWP and UTWV, a rapid increase of IWP with increasing SST and a 2-3 times increase in the slope of UTWV versus SST for SSTs warmer than ~300 K. We argue that the relative concentrations of IWP to UTWV in both observations and models is too small to significantly influence the observed moistening of the upper troposphere (UT).

John, V. O.; Soden, B. J.

2006-10-01

266

Study of the behavior of tritiated water vapor in concrete materials  

NASA Astrophysics Data System (ADS)

A fusion reactor requires high levels of safety and public acceptability, so safe confinement of tritium is a key issues. In order to understand tritium behavior in the concrete reactor components, sorption and desorption experiments were carried out as a function of the exposure time for sorption and the kind of purge gas for desorption. The samples used were cement paste, mortar and concrete. These samples were exposed to 740-1110 Bq/cm 3 of HTO vapor in 1 kPa of H 2O vapor at room temperature. Desorption experiments were carried out using N 2 purging gas with water vapor by the thermal desorption method. The concrete materials became almost saturated with HTO within about 1-6 months. Though the chemical form of tritium desorbed from the sample was mostly HTO, HT and other compounds were also detected above 673 K.

Kobayashi, Kazuhiro; Iwai, Yasunori; Hayashi, Takumi; Yamanishi, Toshihiko

2011-10-01

267

CRISM Limb Observations of Aerosols and Water Vapor  

NASA Technical Reports Server (NTRS)

Near-infrared spectra taken in a limb-viewing geometry by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on-board the Mars Reconnaissance Orbiter (MRO) provide a useful tool for probing atmospheric structure. Here we describe preliminary work on the retrieval of vertical profiles of aerosols and water vapor from the CRISM limb observations. The first full set of CRISM limb observations was taken in July 2009, with subsequent limb observations planned once every two months. Each set of limb observations contains about four dozen scans across the limb giving pole-to-pole coverage for two orbits at roughly 100 and 290 W longitude. Radiative transfer modeling taking account of aerosol scattering in the limb-viewing geometry is used to model the observations. The retrievals show the height to which dust and water vapor extend and the location and height of water ice clouds. Results from the First set of CRISM limb observations (July 2009, Ls=300) show dust aerosol well-mixed to about three scale heights above the surface with thin water ice clouds above the dust near the equator and at mid-northern latitudes. Water vapor is concentrated at high southern latitudes.

Smith, Michael D.; Wolff, M.J.; Clancy, R.T.; Seelos, F.; Murchie, S.L.

2009-01-01

268

Study of the effect of water vapor on a glass RPC with and without freon  

Microsoft Academic Search

We studied the effects of freon (fluoride) in a chamber gas on damaging the glass electrodes combined with water vapor (1000–2000ppm). The damage was observed only for the combination of freon and water vapor.

T. Kubo; H. Sakaue; Y. Teramoto; E. Nakano; T. Takahashi

2003-01-01

269

Raman lidar measurements of water vapor and aerosol/clouds during the FIRE/SPECTRE field campaign  

NASA Technical Reports Server (NTRS)

Water vapor is one of the most important constituents of the earth's atmosphere. It has a major impact on both atmospheric dynamics and radiative transfer. From a dynamic standpoint, the distribution of water vapor with height determines convective stability which is the major indicator of destructive storm development. Also, water vapor stored in the planetary boundary layer acts as the fuel to intensify severe weather. In regards to radiative transfer, water vapor is the most active IR molecule in the atmosphere. It is more effective in absorbing and emitting IR radiation than either carbon dioxide or methane, and thus plays an important role in global change. The main objective of FIRE (First ISSCCP (International Satellite Cloud Climatology Project) Regional Experiment) was to study the development and radiative characteristics of cirrus clouds. The SPECTRE (Spectral Radiation Experiment) project was designed to acquire the necessary atmospheric observations to compare radiative measurements with radiative transfer theory, with special emphasis on understanding the water vapor spectral continuum. The FIRE/SPECTRE field campaign was conducted during Nov. - Dec. 1991 in Coffeyville, Kansas. A complete understanding of water vapor, its distribution with height, and its temporal variation was important for both experiments.

Melfi, S. H.; Whiteman, D.; Ferrare, R.; Evans, K.; Goldsmith, J. E. M.; Lapp, M.; Bisson, S. E.

1992-01-01

270

Development of a preprototype vapor compression distillation water recovery subsystem  

NASA Technical Reports Server (NTRS)

The activities involved in the design, development, and test of a preprototype vapor compression distillation water recovery subsystem are described. This subsystem, part of a larger regenerative life support evaluation system, is designed to recover usable water from urine, urinal rinse water, and concentrated shower and laundry brine collected from three space vehicle crewmen for a period of 180 days without resupply. Details of preliminary design and testing as well as component developments are included. Trade studies, considerations leading to concept selections, problems encountered, and test data are also presented. The rework of existing hardware, subsystem development including computer programs, assembly verification, and comprehensive baseline test results are discussed.

Johnson, K. L.

1978-01-01

271

Water vapor, water-ice clouds, and dust in the North Polar Region  

NASA Technical Reports Server (NTRS)

The behavior of water vapor, water-ice and dust in the Martian atmosphere is important for understanding the overall Martian climate system, which is characterized by three main cycles: water, including water-ice, dust, and CO2. Understanding these cycles will lend insight into the behavior of the atmospheric dynamics, the atmosphere's ability to transport dust, water-ice, and vapor to different parts of the planet, and how that ability changes as a function of dust and water-ice loading.

Tamppari, Leslie K.; Smith, Michael D.; Bass, Deborah S.; Hale, Amy S.

2006-01-01

272

Temperature/pressure and water vapor sounding with microwave spectroscopy  

NASA Technical Reports Server (NTRS)

Two intense microwave spectra lines exist in the martian atmosphere that allow unique sounding capabilities: water vapor at 183 GHz and the (2-1) rotational line of CO at 230 GHz. Microwave spectra line sounding is a well-developed technique for the Earth's atmosphere for sounding from above from spacecraft and airplanes, and from below from fixed surface sites. Two simple instruments for temperature sounding on Mars (the CO line) and water vapor measurements are described. The surface sounder proposed for the MESUR sites is designed to study the boundary layer water vapor distribution and the temperature/pressure profiles with vertical resolution of 0.25 km up to 1 km with reduced resolution above approaching a scale height. The water channel will be sensitive to a few tenths of a micrometer of water and the temperature profile will be retrieved to an accuracy between 1 and 2 K. The latter is routinely done on the Earth using oxygen lines near 60 GHz. The measurements are done with a single-channel heterodyne receiver looking into a 10-cm mirror that is canned through a range of elevation angles plus a target load. The frequency of the receiver is sweep across the water and CO lines generating the two spectra at about 1-hr intervals throughout the mission. The mass and power for the proposed instrument are 2 kg and 5-8 W continuously. The measurements are completely immune to the atmospheric dust and ice particle loads. It was felt that these measurements are the ultimate ones to properly study the martian boundary layer from the surface to a few kilometers. Sounding from above requires an orbiting spacecraft with multichannel microwave spectrometers such as the instrument proposed for MO by a subset of the authors, a putative MESUR orbiter, and a proposed Discovery mission called MOES. Such an instrument can be built with less than 10 kg and use less than 15 W. The obvious advantage of this approach is that the entire atmosphere can be sounded for temperature and water vapor in a few hours with somewhat better than a scale height resolution. If a bigger mirror is used (greater than 30 cm) limb sounding geometry can be employed and half scale height resolution achieved to altitudes up to at least 60 km. Again, the measurements are immune to dust and ice loads. Water vapor sensitivity of 0.1 micrometer can be achieved (even with a nadir instrument) and temperature profiles retrieved to an accuracy of better than 2 K from the surface to about 60 km. Winds can be measured from the doppler shifts of CO lines in the limb sounding mode.

Muhleman, D. O.; Janssen, M. A.; Clancy, R. T.; Gulkis, S.; Mccleese, D. J.; Zurek, R.; Haberle, R. M.; Frerking, M.

1992-01-01

273

Prediction of water vapor transport rates across polyvinylchloride packaging systems using a novel radiotracer method  

Microsoft Academic Search

A radiotracer method is used to study the transport properties of water vapor in polyvinylchloride (PVC), a plastic commonly used in the packaging of parenteral solutions. Water vapor transport across a PVC film appears to be Fickian in nature. Using the steady-state solution of Fick's second law and the permeability coefficient of water vapor across the PVC film obtained using

R. W. Wood; M. J. Mulski; W. Y. Kuu

1990-01-01

274

Retrieval of 3-D Water Vapor Field Using a Network of Scanning Compact Microwave Radiometers  

Microsoft Academic Search

Quantitative precipitation forecasting is currently limited by the paucity of observations of thermodynamic variables in the troposphere, including water vapor. Specifically, measurements of 3-D water vapor fields are needed at sub-meso-?? scales in pre- storm conditions. This can be achieved using a network of remote sensors to retrieve the water vapor field with high spatial and temporal resolution. Such measurements

Sharmila Padmanabhan; Steven C. Reising; Jothiram Vivekanandan

2008-01-01

275

Comparison of precipitable water vapor derived from radiosonde, GPS, and Moderate-Resolution Imaging Spectroradiometer measurements  

Microsoft Academic Search

Atmospheric water vapor is highly variable in both space and time across the Earth, and knowledge of the distribution of water vapor is essential in understanding weather and global climate. In addition, knowledge of the amount of atmospheric water vapor is required for high-precision interferometric synthetic aperture radar (InSAR) applications due to its significant impact on microwave signals, which is

Zhenhong Li; Jan-Peter Muller; Paul Cross

2003-01-01

276

Atmospheric water vapor estimate through MW attenuation measurements on LEO-LEO satellite configuration  

Microsoft Academic Search

We propose the utilization of a satellite system, composed by a couple of LEO (low Earth orbit) satellites operating in the 18-22 GHz range (close to the 22.235 GHz absorption line of water vapor), to estimate the total content of water vapor (IWV, integrated water vapor) along the propagation path between the two satellites (one of them carrying a transmitter,

Fabrizio Cuccoli; Luca Facheris; Dino Giuli; Marco Pellegrini

2003-01-01

277

Toward a plant-based proxy for the isotope ratio of atmospheric water vapor  

Microsoft Academic Search

Atmospheric water vapor is a major component of the global hydrological cycle, but the isotopic balance of vapor is largely unknown. Here, using models and observations, we show that the leaf water d18O in the tropical Crassulacean acid metabolism (CAM) epiphyte Tillandsia usneoides is controlled by the d18O of atmospheric water vapor in a predictable manner, irrespective of precipitation inputs.

BRENT R. HELLIKER; HOWARD GRIFFITHS

2007-01-01

278

A robust retrieval of water vapor column in dry Arctic conditions using the rotating shadowband spectroradiometer  

Microsoft Academic Search

A method to retrieve water vapor column using the 940-nm water vapor absorption band in dry Arctic conditions is presented. The retrievals with this method are stable with respect to uncertainties in instrument radiometric calibration, air pressure, solar source function, and aerosols. The water vapor column was retrieved with this method using spectra obtained with the rotating shadowband spectroradiometer (RSS)

P. Kiedron; J. Michalsky; B. Schmid; D. Slater; J. Berndt; L. Harrison; P. Racette; E. Westwater; Y. Han

2001-01-01

279

Column Water Vapor Retrievals Based on Rotating Shadowband Spectroradiometer (RSS) Direct Solar Irradiance Measurements  

Microsoft Academic Search

Several investigators have retrieved column water vapor using sunphotometry through the 940-nm water vapor absorption band. In this paper, we retrieve water vapor using an approach that removes the requirement of an accurate understanding of the absolute response of the instrument, but, instead, relies on relative responses within the 940-nm absorption band and just outside the band in the continuum.

J. J. Michalsky; Q.-L. Min; P. W. Kiedron; D. W. Slater; J. C. Barnard

280

Evapotranspiration partitioning in a semi-arid African savanna using stable isotopes of water vapor  

NASA Astrophysics Data System (ADS)

Evapotranspiration (ET) represents a major flux of water out of semi-arid ecosystems. Thus, understanding ET dynamics is central to the study of African savanna health and productivity. At our study site in central Kenya (Mpala Research Centre), we have been using stable isotopes of water vapor to partition ET into its constituent parts of plant transpiration (T) and soil evaporation (E). This effort includes continuous measurement (1 Hz) of ?2H and ?18O in water vapor using a portable water vapor isotope analyzer mounted on a 22.5 m eddy covariance flux tower. The flux tower has been collecting data since early 2010. The isotopic end-member of ?ET is calculated using a Keeling Plot approach, whereas ?T and ?E are measured directly via a leaf chamber and tubing buried in the soil, respectively. Here we report on a two recent sets of measurements for partitioning ET in the Kenya Long-term Exclosure Experiment (KLEE) and a nearby grassland. We combine leaf level measurements of photosynthesis and water use with canopy-scale isotope measurements for ET partitioning. In the KLEE experiment we compare ET partitioning in a 4 ha plot that has only seen cattle grazing for the past 15 years with an adjacent plot that has undergone grazing by both cattle and wild herbivores (antelope, elephants, giraffe). These results are compared with a detailed study of ET in an artificially watered grassland.

Soderberg, K.; Good, S. P.; O'Connor, M.; King, E. G.; Caylor, K. K.

2012-04-01

281

Isobaric vapor–liquid and vapor–liquid–liquid equilibrium data for the system water + ethanol + cyclohexane  

Microsoft Academic Search

Isobaric vapor–liquid (VLE) and vapor–liquid–liquid equilibria (VLLE) were measured for the ternary system water+ethanol+cyclohexane at 101.3kPa. The experimental determination was carried out in a dynamic equilibrium still with circulation of both the vapor and liquid phases, equipped with an ultrasonic homogenizer. The experimental data demonstrated the existence of a ternary heterogeneous azeotrope at 335.6K with a composition of 0.188, 0.292,

V. Gomis; R. Pedraza; M. D. Saquete

2005-01-01

282

Water vapor analysis with use of sunphotometry and radiosoundings  

NASA Astrophysics Data System (ADS)

Information about vertically integrated content of water vapor in the atmosphere and type, composition and concentration of aerosols is relevant in many types of atmospheric studies. Such information is required to understand mechanisms of global climate and its further modeling (Smirnov et al., 2000). This work is devoted to the description of a basic technique of analysis and comparing the derivation of Columnar Water Vapor (CWV) from different instruments, such as a radiosonde and a sunphotometer. The measurements were carried out using Microtops II Ozone Monitor & Sunphotometer during the cruises onboard the R/V Oceania (13 cruises) and from one cruise onboard of the SY TASK in the southern Baltic Sea. Measurements were collected for the NASA program Maritime Aerosol Network. Data collected with the DiGICORA III Radiosonde (RS92) come from the webpage of the University of Wyoming, Department of Atmospheric Science. The first instrument, sunphotometer, allows us to collect data on days that are cloud-free. The Microtops II is capable of measuring the total ozone column, total precipitable water vapor and aerosol optical depth at 1020 nm (Morys et al. 2001; Ichoku et al., 2002). Each of these parameters is automatically derived. Data collected by Microtops have been processed with the pre- and post-field calibration and automatic cloud clearing. Precipitable water vapor in the column was derived from the 936nm channel. Detailed data description is available on the AERONET webpage. In radiousoundings the total precipitable water is the water that occurs in a vertical column of a unit cross-sectional area between any two specified levels, commonly expressed as from the earth's surface to the 'top' of the atmosphere. The Integrated Precipitable Water Vapor (IPWV) is the height of liquid water that would result from the condensation of all water vapor in a column. The study of one cruise (29 March - 20 April) shows that 241 Microtops measurements were made, each of them in a series of five 'shots'. Then only the lowest value was chose. Then the data were matched with the radiosonde data, based on date and time. The example result with the selected data for the comparison shows that the correlation is strong for both instruments (0.67), despite of low data number that left to compare. The correlation between aerosol optical depth and water vapor content in the total atmospheric column is not high (0.42). Also diurnal variations of the aerosol optical depth and precipitable water were insignificant (AOD=0.09±0.03;PWV =11.42±3.50). Some of the differences in correlation can be attributed to the distance between location of the instruments and to the reference instrument, as well as the conditions in the atmosphere like wind speed and its direction. These analyses are presented in order to quantify the accuracy of different techniques and algorithms to estimate WV present in the Earth's atmosphere. Nevertheless, the data comparison shows discrepancy at a lower level between the instruments. The support for this study was provided by the POLAND-AOD network and the project Satellite Monitoring of the Baltic Sea Environment - SatBa?tyk founded by European Union through European Regional Development Fund contract No. POIG 01.01.02-22-011/09.

Pakszys, Paulina; Zielinski, Tymon; Petelski, Tomek; Makuch, Przemyslaw; Strzalkowska, Agata; Markuszewski, Piotr; Kowalczyk, Jakub

2014-05-01

283

IR spectroscopy of water vapor confined in nanoporous silica aerogel.  

PubMed

The absorption spectrum of the water vapor, confined in the nanoporous silica aerogel, was measured within 5000-5600 cm(-1) with the IFS 125 HR Fourier spectrometer. It has been shown, that tight confinement of the molecules by the nanoporous size leads to the strong lines broadening and shift. For water vapor lines, the HWHM of confined molecules are on the average 23 times larger than those for free molecules. The shift values are in the range from -0.03 cm(-1) to 0.09 cm(-1). Some spectral lines have negative shift. The data on the half-widths and center shifts for some strongest H(2)O lines have been presented. PMID:21164954

Ponomarev, Yu N; Petrova, T M; Solodov, A M; Solodov, A A

2010-12-01

284

Profiling atmospheric water vapor using a fiber laser lidar system.  

PubMed

A compact, lightweight, and efficient fiber laser lidar system has been developed to measure water vapor profiles in the lower atmosphere of Earth or Mars. The line narrowed laser consist of a Tm:germanate fiber pumped by two 792 nm diode arrays. The fiber laser transmits approximately 0.5 mJ Q- switched pulses at 5 Hz and can be tuned to water vapor lines near 1.94 microm with linewidth of approximately 20 pm. A lightweight lidar receiver telescope was constructed of carbon epoxy fiber with a 30 cm Fresnel lens and an advanced HgCdTe APD detector. This system has made preliminary atmospheric measurements. PMID:20119001

De Young, Russell J; Barnes, Norman P

2010-02-01

285

A nonisothermal emissivity and absorptivity formulation for water vapor  

NASA Technical Reports Server (NTRS)

An emissivity approach is taken to modeling fluxes and cooling rates in the atmosphere. The nonisothermal water vapor long wave radiation emissivity and absorptivity model that is developed satisfies the requirements of defining a monochromatic transfer equation for predicting water vapor emissions. Predictions made with the model compare favorably with fluxes predicted by a radiation model for narrow-band emissions in 5 kayser intervals. The spectral resolution assumed in narrow-band models is shown to be an arbitrary parameter and, if a far wing continuum-type opacity is included in the emissivity scheme presented, results can be obtained which are as accurate as predictions made with state of the art line-by-line (LBL) calculations.

Ramanathan, V.; Downey, P.

1986-01-01

286

A new look at the atmospheric water cycle: measurements of water vapor and its main isotopologue using SCIAMACHY  

Microsoft Academic Search

Water vapor is by far the most important greenhouse gas in the atmosphere. As a warmer atmosphere can contain more water vapor, a positive feedback effect with respect to climate change is expected. The distribution of water vapor is very inhomogeneous and variable, unlike that of other greenhouse gases. In the light of climate reconstructions and predictions, it is therefore

Remco Scheepmaker; Christian Frankenberg; Ilse Aben; Hans Schrijver; Annemieke Gloudemans; Thomas Roeckmann; Kei Yoshimura

2010-01-01

287

Prospects for an economical, eye-safe water vapor lidar  

Microsoft Academic Search

A conceptual design and simulations are presented to explore the feasibility for an economical, eye-safe water vapor lidar. The design is based on using GaAlAs laser diode arrays in the lidar transmitter and photon counting silicon avalanche photodiodes (APDs) in the lidar receiver. Simulations are presented to demonstrate that a lidar using a laser diode powered transmitter and an APD

J. A. Reagan; T. W. Cooley; J. A. Shaw

1993-01-01

288

The polyurethane membranes with temperature sensitivity for water vapor permeation  

Microsoft Academic Search

The size and shape of free-volume holes available in membrane materials control the rate of gas diffusion and its permeability. Based on this principle, two segmented thermo-sensitive polyurethane (TSPU) membranes with functional gates, i.e. the ability to sense and respond to external thermo-stimuli, were synthesized and used for water vapor controllable permeation. Differential scanning calorimetry (DSC), positron annihilation lifetimes (PAL),

Yi Chen; Yan Liu; Haojun Fan; Hui Li; Bi Shi; Hu Zhou; Biyu Peng

2007-01-01

289

Numerical modeling of water injection into vapor-dominatedgeothermal reservoirs  

Microsoft Academic Search

Water injection has been recognized as a powerful techniquefor enhancing energy recovery from vapor-dominated geothermal systemssuch as The Geysers. In addition to increasing reservoir pressures,production well flow rates, and long-term sustainability of steamproduction, injection has also been shown to reduce concentrations ofnon-condensible gases (NCGs) in produced steam. The latter effectimproves energy conversion efficiency and reduces corrosion problems inwellbores and surface

Pruess; Karsten

2006-01-01

290

Apparent temperature dependence on localized atmospheric water vapor  

NASA Astrophysics Data System (ADS)

The atmosphere is a critical factor in remote sensing. Radiance from a target must pass through the air column to reach the sensor. The atmosphere alters the radiance reaching the sensor by attenuating the radiance from the target via scattering and absorption and by introducing an upwelling radiance. In the thermal infrared, these effects will introduce errors in the derived apparent temperature of the target if not properly accounted for. The temperature error is defined as the difference between the target leaving apparent temperature and observed apparent temperature. The effects of the atmosphere must be understood in order to develop methods to compensate for this error. Different atmospheric components will affect the radiation passing through it in different ways. Certain components may be more important than others depending on the remote sensing application. The authors are interested in determining the actual temperature of the superstructure that composes a mechanical draft cooling tower (MDCT), hence water vapor is the primary constituent of concern. The tower generates a localized water vapor plume located between the target and sensor. The MODTRAN radiative transfer code is used to model the effects of a localized exhaust plume from a MDCT in the longwave infrared. The air temperature and dew point depression of the plume and the thickness of the plume are varied to observe the effect on the apparent temperature error. In addition, the general atmospheric conditions are varied between two standard MODTRAN atmospheres to study any effect that ambient conditions have on the apparent temperature error. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) modeling tool is used to simulate the radiance reaching a thermal sensor from a target after passing through the water vapor plume. The DIRSIG results are validated against the MODTRAN results. This study shows that temperature errors of as much as one Kelvin can be attributed to the presence of a localized water vapor plume.

Montanaro, Matthew; Salvaggio, Carl; Brown, Scott D.; Messinger, David W.; Garrett, Alfred J.

2008-05-01

291

Raman-shifted dye laser for water vapor DIAL measurements  

Microsoft Academic Search

For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, we have generated narrowband (--0.03-cm⁻¹) laser radiation at 720- and 940-nm wavelengths by stimulated Raman scattering (SRS) using the narrow linewidth (--0.02-cm⁻¹) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20% and

B. E. Grossmann; U. N. Singh; N. S. Higdon; L. J. Cotnoir; T. D. Wilkerson; E. V. Browell

1987-01-01

292

Raman-shifted dye laser for water vapor DIAL measurements  

Microsoft Academic Search

For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, narrowband (about 0.03\\/cm) laser radiation at 720- and 940-nm wavelengths was generated by stimulated Raman scattering (SRS), using the narrow linewidth (about 0.02\\/cm) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20

B. E. Grossmann; U. N. Singh; L. J. Cotnoir; T. D. Wilkerson; N. S. Higdon; E. V. Browell

1987-01-01

293

Sensing integrated water vapor along GPS ray paths  

Microsoft Academic Search

We demonstrate sensing of integrated slant-path water vapor (SWV) along ray paths between Global Positioning System (GPS) satellites and receivers. We use double differencing to remove GPS receiver and satellite clock errors and 85-cm diameter choke ring antennas to reduce ground-reflected multipath. We compare more than 17,000 GPS and pointed radiometer double difference observations above 20° elevation and find 1.3

Randolph Ware; Chris Alber; Christian Rocken; Fredrick Solheim

1997-01-01

294

Paralinear oxidation of CVD SiC in water vapor  

Microsoft Academic Search

Silicon carbide-based composites are currently being developed for use in the complex environments of heat engines. The oxidation kinetics of CVD SiC were monitored by thermogravimetric analysis (TGA) in a 50% HâO\\/50% Oâ gas mixture flowing at 4.4 cm\\/s for temperatures between 1,200 and 1,400 C. Paralinear weight change kinetics were observed as the water vapor oxidized the SiC and

Elizabeth J. Opila; Raiford E. Hann

1997-01-01

295

Extratropical influence of upper tropospheric water vapor on Greenhouse warming  

NASA Technical Reports Server (NTRS)

Despite its small quantity, the importance of upper tropospheric water vapor is its ability to trap the longwave radiation emitted from the Earth's surface, namely the greenhouse effect. The greenhouse effect is defined quantitatively as the difference between the longwave flux emitted by the Earth's surface and the outgoing longwave radiation (OLR) flux emitted from the top of the atmosphere (TOA) (Raval and Ramanathan 1989).

Liu, W. Timothy; Hu, Hua

1997-01-01

296

Vapor-deposited water and nitric acid ices  

NASA Astrophysics Data System (ADS)

Ices formed by vapor deposition have been the subject of numerous laboratory investigations in connection with snow and glaciers on the ground, ice clouds in the terrestrial atmosphere, surfaces of other planets and their satellites, and the interstellar medium. In this review we will focus on these specific subjects: (1) heterogeneous chemistry on the surfaces of polar stratospheric clouds (PSCs) and (2) surfaces of satellites of the outer planets in our solar system. Stratospheric ozone provides a protective shield for mankind and the global biosphere from harmful ultraviolet solar radiation. In past decades, theoretical atmospheric models for the calculation of ozone balance frequently used only homogeneous gas-phase reactions in their studies. Since the discovery of the Antarctic ozone hole in 1985, however, it has been demonstrated that knowledge of heterogeneous reactions on the surface of PSCs is definitely needed to understand this significant natural event due to the anthropogenic emission of chlorofluorocarbons (CFCs). We will briefly discuss the experimental techniques for the investigation of heterogeneous chemistry on ice surfaces carried out in our laboratories. The experimental apparatus used include: several flow-tube reactors, an electron-impact ionization mass spectrometer, a Fourier transform infrared spectrometer, a BET adsorption apparatus, and a scanning environmental electron microscope. The adsorption experiments and electron microscopic work have demonstrated that the vapor-deposited ices are highly porous. Therefore, it is necessary to develop theoretical models for the elucidation of the uptake and reactivity of trace gases in porous ice substrates. Several measurements of uptake and reaction probabilities of these trace gases on water ices and nitric acid ices have been performed under ambient conditions in the upper troposphere and lower stratosphere, mainly in the temperature range 180-220 K. The trace gases of atmospheric importance in heterogeneous chemistry include: ClONO2, HCl, HOCl, and HNO3. In addition, recent interest in the possible landing of a robotic spacecraft on the surface of Europa, one of the Galilean satellites of Jupiter, and ground based telescopic observations demand detailed knowledge of the physical properties of the icy surfaces of the outer planets and their satellites. Lower temperature studies in the range 77-150 K using both electron microscopy and adsorption isotherms (BET surface area measurements) have revealed some intriguing observations that may provide some insights for remote sensing of these satellite surfaces. Finally, we will attempt to summarize our recent results and suggest future research directions in both theoretical and laboratory investigations.

Leu, Ming-Taun; Keyser, Leon F.

297

Water vapor intrusions into the High Arctic during winter  

NASA Astrophysics Data System (ADS)

The meridional transport of water vapor into the High Arctic, accompanied by dry enthalpy and clouds, impacts the surface radiative forcing. The evolution of one such moist intrusion over 9-11 February 2010 is presented. The event is analyzed using a unique blend of measurements including a new pan-Arctic retrieval of column water vapor from the Microwave Humidity Sounders, water vapor profiles from a Raman lidar and a ground-based microwave radiometer at the Polar Environment Atmospheric Research Laboratory (PEARL), in Eureka (80°N, 86°W), on Ellesmere Island in the Canadian High Arctic. A radiation model reveals the intrusion is associated with a 17 W m-2 average increase in downwelling longwave irradiance. Optically thin clouds, as observed by the lidar, contribute a further 20 W m-2 to the downwelling longwave irradiance at their peak. Intrusion events are shown to be a regular occurrence in the Arctic winter with implications for the understanding of the mechanisms driving Arctic Amplification.

Doyle, J. G.; Lesins, G.; Thackray, C. P.; Perro, C.; Nott, G. J.; Duck, T. J.; Damoah, R.; Drummond, J. R.

2011-06-01

298

Adsorption characteristics of water vapor on honeycomb adsorbents  

NASA Astrophysics Data System (ADS)

Recovery of tritium released into working areas in nuclear fusion plants is a key issue of safety. A large volume of air from tritium fuel cycle or vacuum vessel should be processed by air cleanup system (ACS). In ACS, tritium gas is oxidized by catalysts, and then tritiated water vapor is collected by adsorbents. This method can remove tritium effectively, whereas high throughput of air causes high-pressure drop in catalyst and adsorbent beds. In this study, the applicability of honeycomb-type adsorbents, which offers a useful advantage in terms of their low-pressure drop, to ACS was examined, in comparison with conventional pebble-type adsorbent. Honeycomb-type adsorbent causes far less pressure drop than pebble-type adsorbent beds. Adsorption capacity of water vapor on a honeycomb-type adsorbent is slightly lower than that on a pebble-type adsorbent, while adsorption rate of water vapor on honeycomb-type adsorbent is much higher than that of pebble-type adsorbent.

Wajima, Takaaki; Munakata, Kenzo; Takeishi, Toshiharu; Hara, Keisuke; Wada, Kouhei; Katekari, Kenichi; Inoue, Keita; Shinozaki, Yohei; Mochizuki, Kazuhiro; Tanaka, Masahiro; Uda, Tatsuhiko

2011-10-01

299

Molecular dynamics of the water liquid-vapor interface  

NASA Technical Reports Server (NTRS)

The results of molecular dynamics calculations on the equilibrium interface between liquid water and its vapor at 325 K are presented. For the TIP4P model of water intermolecular pair potentials, the average surface dipole density points from the vapor to the liquid. The most common orientations of water molecules have the C2 nu molecular axis roughly parallel to the interface. The distributions are quite broad and therefore compatible with the intermolecular correlations characteristic of bulk liquid water. All near-neighbor pairs in the outermost interfacial layers are hydrogen bonded according to the common definition adopted here. The orientational preferences of water molecules near a free surface differ from those near rigidly planar walls which can be interpreted in terms of patterns found in hexagonal ice 1. The mean electric field in the interfacial region is parallel to the mean polarization which indicates that attention cannot be limited to dipolar charge distributions in macroscopic descriptions of the electrical properties of this interface. The value of the surface tension obtained is 132 +/- 46 dyn/cm, significantly different from the value for experimental water of 68 dyn/cm at 325 K.

Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

1987-01-01

300

In search of water vapor on Jupiter: Laboratory measurements of the microwave properties of water vapor under simulated jovian conditions  

NASA Astrophysics Data System (ADS)

Detection and measurement of atmospheric water vapor in the deep jovian atmosphere using microwave radiometry has been discussed extensively by Janssen et al. (Janssen, M.A., Hofstadter, M.D., Gulkis, S., Ingersoll, A.P., Allison, M., Bolton, S.J., Levin, S.M., Kamp, L.W. [2005]. Icarus 173 (2), 447-453.) and de Pater et al. (de Pater, I., Deboer, D., Marley, M., Freedman, R., Young, R. [2005]. Icarus 173 (2), 425-447). The NASA Juno mission will include a six-channel microwave radiometer system (MWR) operating in the 1.3-50 cm wavelength range in order to retrieve water vapor abundances from the microwave signature of Jupiter (see, e.g., Matousek, S. [2005]. The Juno new frontiers mission. Tech. Rep. IAC-05-A3.2.A.04, California Institute of Technology). In order to accurately interpret data from such observations, nearly 2000 laboratory measurements of the microwave opacity of H 2O vapor in a H 2/He atmosphere have been conducted in the 5-21 cm wavelength range (1.4-6 GHz) at pressures from 30 mbars to 101 bars and at temperatures from 330 to 525 K. The mole fraction of H 2O (at maximum pressure) ranged from 0.19% to 3.6% with some additional measurements of pure H 2O. These results have enabled development of the first model for the opacity of gaseous H 2O in a H 2/He atmosphere under jovian conditions developed from actual laboratory data. The new model is based on a terrestrial model of Rosenkranz et al. (Rosenkranz, P.W. [1998]. Radio Science 33, 919-928), with substantial modifications to reflect the effects of jovian conditions. The new model for water vapor opacity dramatically outperforms previous models and will provide reliable results for temperatures from 300 to 525 K, at pressures up to 100 bars and at frequencies up to 6 GHz. These results will significantly reduce the uncertainties in the retrieval of jovian atmospheric water vapor abundances from the microwave radiometric measurements from the upcoming NASA Juno mission, as well as provide a clearer understanding of the role deep atmospheric water vapor may play in the decimeter-wavelength spectrum of Saturn.

Karpowicz, Bryan M.; Steffes, Paul G.

2011-03-01

301

Kinetics of water vapor diffusion in activated carbon  

NASA Astrophysics Data System (ADS)

We describe an experimental method for studying rapid processes of water vapor sorption by fine-dispersed and porous materials. The concentration of gas-phase water molecules is detected during adsorption by a laser-diode spectrometer. The kinetic pressure curves are recorded in a time window of 10-1 to 103 s and are analyzed using analogy of the diffusion flow with the electric current in a branched RC circuit. The proposed model establishes the relation between the kinetics curves being measured and the structural parameters of the medium.

Kurmasheva, D. M.; Kapralov, P. O.; Travkin, V. D.; Artemov, V. G.; Tikhonov, V. I.; Volkov, A. A.

2014-05-01

302

Microwave Radiometer Networks for Measurement of the Spatio-Temporal Variability of Water Vapor  

NASA Astrophysics Data System (ADS)

Tropospheric water vapor plays a key role in the prediction of convective storm initiation, precipitation and extreme weather events. Conventionally, water vapor profiles are derived from dewpoint and temperature measurements using instrumented weather balloons, including radiosondes. These balloons take approximately one hour to measure from surface to tropopause, and transmitter-sensor packages cannot be reused. Such in-situ measurements provide profiles with very high vertical resolution but with severe limitations in temporal and spatial coverage. Raman lidars use active optical techniques to provide comparable vertical resolution and measurement accuracy to radiosondes. However, these lidars are bulky and expensive, and their operation is limited to clear-sky conditions due to the high optical opacity of clouds. Microwave radiometers provide path-integrated water vapor and liquid water with high temporal resolution during nearly all weather conditions. If multiple frequencies are measured near the water vapor resonance, coarse vertical profiles can be obtained using statistical inversion. Motivated by the need for improved temporal and spatial resolutions, a network of elevation and azimuth scanning radiometers is being developed to provide coordinated volumetric measurements of tropospheric water vapor. To realize this network, two Miniaturized Water Vapor profiling Radiometers (MVWR) have been designed and fabricated at Colorado State University. MWVR is small, light-weight, consumes little power and is highly stable. To reduce the mass, volume, cost and power consumption as compared to traditional waveguide techniques, MWVR was designed based on monolithic microwave integrated-circuit technology developed for the wireless communication and defense industries. It was designed for network operation, in which each radiometer will perform a complete volumetric scan within a few minutes, and overlapping scans from multiple sensors will be combined tomographically to retrieve the 3D water vapor field as a function of time. In this paper we report new, collocated measurements from a zenith-looking MWVR and a five-channel Radiometrics profiler during REFRACTT (Refractivity Experiment For H2O Research And Collaborative Operational Technology Transfer) led by NCAR during the summer of 2006.

Reising, S. C.; Iturbide-Sanchez, F.; Padmanabhan, S.

2006-12-01

303

Profiling of Atmospheric Water Vapor from the SSM/T-2 Radiometric Measurements  

NASA Technical Reports Server (NTRS)

An advantage of using the millimeter-wave measurements for water vapor profiling is the ability to probe beyond a moderate cloud cover. Such a capability has been demonstrated from an airborne MIR (Millimeter-wave Imaging Radiometer) flight over the Pacific Ocean during an intense observation period of TOGA/COARE (Tropical Ocean Global Atmosphere/ Couple Ocean Atmospheric Response Experiment) in early 1993. A Cloud Lidar System (CLS) and MODIS Airborne Simulator (MAS) were on board the same aircraft to identify the presence of clouds and cloud type. The retrieval algorithm not only provides output of a water vapor profile, but also the cloud liquid water and approximate cloud altitude required to satisfy convergence of the retrieval. The validity of these cloud parameters has not been verified previously. In this document, these cloud parameters are compared with those derived from concurrent measurements from the CLS and AMPR (Advanced Microwave Precipitation Radiometer).

Wang, J. R.

2000-01-01

304

Experimental results of flooding experiments in an inclined tube with liquid nitrogen and its vapor  

NASA Astrophysics Data System (ADS)

Counter-current two-phase flow behaviors of saturated liquid nitrogen and its vapor at the onset of flooding are experimentally investigated. The experiments are carried out in a vacuum-insulated 20 mm i.d. transparent tube with the inclination angles of 30°, 45° and 60° corresponding to the horizontal. The common slug flow phenomenon happened with water-air is not observed with liquid nitrogen-vapor, instead, the big interfacial wave is found to be crushed to tiny droplets. The phenomenal difference is primarily attributed to the larger viscosity of water than liquid nitrogen. Correspondingly, the sharp rise of pressure drop with water-air is largely due to the blockage of gas flow by the formed slug, while it is primarily due to the tiny droplet entrainment for the liquid nitrogen-vapor pairs. The effects of inclination angles on the incipient flooding velocity are specially emphasized and investigated. A new correlation base on Ohnesorge number and modified Froude number are presented, and the results coincide with the experimental data of both room-temperature and cryogenic fluids with the uncertainty of 20%.

Chen, Jianye; Xu, Lu; Xiong, Wei; Qiu, Limin; Zhang, Xiaobin

2014-07-01

305

Water vapor diffusion into a nanostructured iron oxyhydroxide.  

PubMed

Water diffusion through 0.4 nm × 0.4 nm wide tunnels of synthesized akaganéite (?-FeOOH) nanoparticles was studied by a coupled experimental-molecular modeling approach. A sorption isotherm model obtained from quartz crystal microbalance measurements suggests that the akaganéite bulk can accommodate a maximum of 22.4 mg of water/g (44% bulk site occupancy) when exposed to atmospheres of up to 16 Torr water vapor. Fourier transform infrared spectroscopy also showed that water molecules interact with (hydr)oxo groups on both the akaganéite bulk and surface. Diffusion reactions through the akaganéite bulk were confirmed through important changes in the hydrogen-bonding environment of bulk hydroxyl groups. Molecular dynamics simulations showed that water molecules are localized in cavities that are bound by eight hydroxyl groups, forming short-lived (<0.5 ps) hydrogen bonds with one another. Diffusion coefficients of water are three orders of magnitude lower than they are in liquid water (D = 0.0-11.1 × 10(-12) m(2)·s(-1)), whereas large integral rotational correlation times are 4 to 15 times higher (?r = 8.4-31.8 ps). Moreover, both of these properties are strongly loading-dependent. The simulations of the interface between the water vapor phase and the (010) surface plane of the akaganéite, where tunnel openings are exposed, revealed sluggish rates of incorporation between interfacial water species and their tunnel counterparts. The presence of defects in the synthesized particles are suspected to contribute to different diffusion rates in the laboratory when compared to those observed in pristine crystalline materials, as studied by molecular modeling. PMID:23701490

Song, Xiaowei; Boily, Jean-François

2013-06-17

306

Sorption and Transport of Water Vapor in Amphiphilic Block Copolymer Films  

Microsoft Academic Search

Water vapor sorption in films consisting of poly(ethylene oxide)?poly(propylene oxide)?poly(ethylene oxide) (PEO?PPO?PEO) amphiphilic block copolymers has been measured gravimetrically at air relative humidity in the range 38–94% at 24°C. The water sorption isotherm was obtained and compared to data for water vapor desorption (drying) for the same system. The kinetics of water vapor sorption were determined. The percentage of water

Zhiyong Gu; Paschalis Alexandridis

2005-01-01

307

Sorption and Transport of Water Vapor in Amphiphilic Block Copolymer Films  

Microsoft Academic Search

Water vapor sorption in films consisting of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) amphiphilic block copolymers has been measured gravimetrically at air relative humidity in the range 38-94% at 248C. The water sorption isotherm was obtained and compared to data for water vapor desorption (drying) for the same system. The kinetics of water vapor sorption were determined. The percentage of water

Zhiyong Gu; Paschalis Alexandridis

2004-01-01

308

Observed Seasonal to Decadal-Scale Responses in Mesospheric Water Vapor  

NASA Technical Reports Server (NTRS)

The 14-yr (1991-2005) time series of mesospheric water vapor from the Halogen Occultation Experiment (HALOE) are analyzed using multiple linear regression (MLR) techniques for their6 seasonal and longer-period terms from 45S to 45N. The distribution of annual average water vapor shows a decrease from a maximum of 6.5 ppmv at 0.2 hPa to about 3.2 ppmv at 0.01 hPa, in accord with the effects of the photolysis of water vapor due to the Lyman-flux. The distribution of the semi-annual cycle amplitudes is nearly hemispherically symmetric at the low latitudes, while that of the annual cycles show larger amplitudes in the northern hemisphere. The diagnosed 11-yr, or solar cycle, max minus min, water vapor values are of the order of several percent at 0.2 hPa to about 23% at 0.01 hPa. The solar cycle terms have larger values in the northern than in the southern hemisphere, particularly in the middle mesosphere, and the associated linear trend terms are anomalously large in the same region. Those anomalies are due, at least in part, to the fact that the amplitudes of the seasonal cycles were varying at northern mid latitudes during 1991-2005, while the corresponding seasonal terms of the MLR model do not allow for that possibility. Although the 11-yr variation in water vapor is essentially hemispherically-symmetric and anti-phased with the solar cycle flux near 0.01 hPa, the concurrent temperature variations produce slightly colder conditions at the northern high latitudes at solar minimum. It is concluded that this temperature difference is most likely the reason for the greater occurrence of polar mesospheric clouds at the northern versus the southern high latitudes at solar minimum during the HALOE time period.

Remsberg, Ellis

2010-01-01

309

Isobaric vapor–liquid equilibria of water–pyridine and water–pyridine–calcium chloride mixtures  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium data at 705±1mmHg for the systems water–pyridine and water–pyridine–CaCl2 were obtained using the modified Othmer circulation still. The experimental data for the water–pyridine system exhibited an azeotropic point at a water composition of 75.0mol% and a temperature of 92.60°C. The isobaric salt-free binary data were compared with predicted vapor–liquid equilibrium (VLE) data using the UNIFAC model. Good

Fahmi A Abu Al-Rub; Ravindra Datta

2001-01-01

310

Measurements of Water Vapor and Total Water on the NASA WB57: Validation and Determination of Cirrus Ice Water Content  

Microsoft Academic Search

We describe an instrument that makes accurate in situ measurements of total water. Cloud ice water content is determined using simultaneous water vapor measurements. The total water instrument integrates an aerodynamically shaped inlet and an in-stream heater with photofragment resonance fluorescence detection to quantitatively measure the total water content of ambient air. The air is isokinetically drawn into the instrument

E. M. Weinstock; J. Smith; D. Sayres; J. Pittman; J. Anderson; R. Herman

2003-01-01

311

Water Vapor in the Protoplanetary Disk of DG Tau  

NASA Astrophysics Data System (ADS)

Water is key in the evolution of protoplanetary disks and the formation of comets and icy/water planets. While high-excitation water lines originating in the hot inner disk have been detected in several T Tauri stars (TTSs), water vapor from the outer disk, where most water ice reservoirs are stored, was only reported in the nearby TTS TW Hya. We present spectrally resolved Herschel/HIFI observations of the young TTS DG Tau in the ortho- and para-water ground-state transitions at 557 and 1113 GHz. The lines show a narrow double-peaked profile, consistent with an origin in the outer disk, and are ~19-26 times brighter than in TW Hya. In contrast, CO and [C II] lines are dominated by emission from the envelope/outflow, which makes H2O lines a unique tracer of the disk of DG Tau. Disk modeling with the thermo-chemical code ProDiMo indicates that the strong UV field, due to the young age and strong accretion of DG Tau, irradiates a disk upper layer at 10-90 AU from the star, heating it up to temperatures of 600 K and producing the observed bright water lines. The models suggest a disk mass of 0.015-0.1 M ?, consistent with the estimated minimum mass of the solar nebula before planet formation, and a water reservoir of ~102-103 Earth oceans in vapor and ~100 times larger in the form of ice. Hence, this detection supports the scenario of ocean delivery on terrestrial planets by the impact of icy bodies forming in the outer disk.

Podio, L.; Kamp, I.; Codella, C.; Cabrit, S.; Nisini, B.; Dougados, C.; Sandell, G.; Williams, J. P.; Testi, L.; Thi, W.-F.; Woitke, P.; Meijerink, R.; Spaans, M.; Aresu, G.; Ménard, F.; Pinte, C.

2013-03-01

312

Reduction of Convection in Closed Tube Vapor Transport Experiments  

NASA Technical Reports Server (NTRS)

The primary objective of this effort was to develop a method for suppressing convective flows during the growth of mercurous chloride crystals by vapor transport in closed tubes to levels approaching those obtained in the microgravity environment. Mercurous chloride was chosen because it is a technologically interesting acoustical optical material whose optical properties are believed to be affected by convective flows. Since the Grashof number scales as the cube of the smallest dimension in the flow system, reduction of the size scale can be extremely effective in reducing unwanted convective flows. However, since materials of practical interest must be grown at least on the cm scale, reduction of the overall growth system is not feasible. But if the region just above the growing crystal could be restricted to a few mm, considerable reduction in flow velocity would result. By suspending an effusive barrier in the growth ampoule just above the growth interface, it should be possible to reduce the convective velocity in this vicinity to levels approaching flows in microgravity. If successful, this growth technique will offer a screening test for proposed space experiments that involve vapor transport to see if reduction of convection will result in improved material and will set a new standard against which the improvements obtained in microgravity may be judged. In addition, it may provide an improved method for preparing materials on Earth whose growth is affected adversely by convection. If the properties of this material can be improved there is a potential commercial interest from Brimrose Inc., who has agreed to fabricate and test devices from the crystals we have grown. This report describes the development of the growth facility, the purification processes developed for preparing the starting material, and the results from growth experiments with and without the effusive baffle. Mercurous chloride turned out to be a more difficult material to deal with than originally anticipated. At growth temperatures, it is extremely sensitive to practically any impurity which causes it to form oxychlorides and/or to decompose into elemental mercury and bichloride of mercury. We were unable to find a suitable method for protecting the magnetic material used to suspend the effusion barrier from the attack of mercurous chloride vapor. Although we were successful in growing single crystals of mercurous chloride without the effusion baffle, they exhibited severe microcracking which we attribute to wall-induced thermal stresses. This leads us to believe that uncontrolled convection may not be the most important problem in the development of this material and a new growth process was attempted that eliminates the wall-induced stress. Unfortunately, the grant ran out before this new method could be adequately tested.

Naumann, R. J.; Tan, Sarwa Bakti; Shin, In-Seok; Kim, Joo Soo

2002-01-01

313

Precipitable water vapor on the Tibetan Plateau estimated by GPS, water vapor radiometer, radiosonde, and numerical weather prediction analysis and its impact on the radiation budget  

Microsoft Academic Search

Precipitable water vapor amounts (PW) determined by Global Positioning System (GPS), radiosonde and operational numerical weather prediction (NWP) system analysis at three stations (Naqu, Gaize, and Deqin) on the Tibetan Plateau are compared. PW measured by water vapor radiometer at Naqu and a low-elevation site, Xian, is used for calibration. The results show that the PW determined by NWP analysis

J. Liu; Z. Sun; H. Liang; X. Xu; P. Wu

2005-01-01

314

Vaporizing Vapor  

NSDL National Science Digital Library

In this demonstration, relative humidity is modeled using a sponge and a pan of water, and the concept of saturation is depicted. Students answer questions examining the relationship between temperature and the capacity of air to hold water vapor. The resource is part of the teacher's guide accompanying the video, NASA Sci Files: The Case of the Phenomenal Weather. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

315

Gas scavenging of insoluble vapors: Condensation of methyl salicylate vapor onto evaporating drops of water  

NASA Astrophysics Data System (ADS)

We have observed the evaporation of acoustically levitated water drops at 0 and 32% relative humidity in a moving gas stream which is nearly saturated with methyl salicylate vapor. The initial evaporation rate is characteristic of a pure water drop and gradually slows until the evaporation rate becomes that of pure methyl salicylate. The quantity of condensed methyl salicylate exceeds its Henry's law solubility in water by factors of more than 30-50. This apparent violation of Henry's law agrees with the concentration enhancements in the liquid phase found by glotfelty et al. (1987, Nature235, 602-605) during their field measurements of organophorus pesticides in fog water. Under our conditions, visual evidence demonstrates the presence of two liquid phases, thus invalidating the use of Henry's law. A continuum evaporation-condensation model for an immiscible two-component system which accounts for evaporative self-cooling of the drop correctly predicts the amount of methyl salicylate condensed onto the water drops.

Seaver, Mark; Peele, J. R.; Rubel, Glenn O.

316

Characterization of the TIP4P-Ew water model: Vapor pressure and boiling point  

NASA Astrophysics Data System (ADS)

The liquid-vapor-phase equilibrium properties of the previously developed TIP4P-Ew water model have been studied using thermodynamic integration free-energy simulation techniques in the temperature range of 274-400 K. We stress that free-energy results from simulations need to be corrected in order to be compared to the experiment. This is due to the fact that the thermodynamic end states accessible through simulations correspond to fictitious substances (classical rigid liquids and classical rigid ideal gases) while experiments operate on real substances (liquids and real gases, with quantum effects). After applying analytical corrections the vapor pressure curve obtained from simulated free-energy changes is in excellent agreement with the experimental vapor pressure curve. The boiling point of TIP4P-Ew water under ambient pressure is found to be at 370.3+/-1.9 K, about 7 K higher than the boiling point of TIP4P water (363.7+/-5.1 K from simulations that employ finite range treatment of electrostatic and Lennard-Jones interactions). This is in contrast to the approximately +15 K by which the temperature of the density maximum and the melting temperature of TIP4P-Ew are shifted relative to TIP4P, indicating that the temperature range over which the liquid phase of TIP4P-Ew is stable is narrower than that of TIP4P and resembles more that of real water. The quality of the vapor pressure results highlights the success of TIP4P-Ew in describing the energetic and entropic aspects of intermolecular interactions in liquid water.

Horn, Hans W.; Swope, William C.; Pitera, Jed W.

2005-11-01

317

Characterization of the TIP4P-Ew water model: vapor pressure and boiling point.  

PubMed

The liquid-vapor-phase equilibrium properties of the previously developed TIP4P-Ew water model have been studied using thermodynamic integration free-energy simulation techniques in the temperature range of 274-400 K. We stress that free-energy results from simulations need to be corrected in order to be compared to the experiment. This is due to the fact that the thermodynamic end states accessible through simulations correspond to fictitious substances (classical rigid liquids and classical rigid ideal gases) while experiments operate on real substances (liquids and real gases, with quantum effects). After applying analytical corrections the vapor pressure curve obtained from simulated free-energy changes is in excellent agreement with the experimental vapor pressure curve. The boiling point of TIP4P-Ew water under ambient pressure is found to be at 370.3+/-1.9 K, about 7 K higher than the boiling point of TIP4P water (363.7+/-5.1 K; from simulations that employ finite range treatment of electrostatic and Lennard-Jones interactions). This is in contrast to the approximately +15 K by which the temperature of the density maximum and the melting temperature of TIP4P-Ew are shifted relative to TIP4P, indicating that the temperature range over which the liquid phase of TIP4P-Ew is stable is narrower than that of TIP4P and resembles more that of real water. The quality of the vapor pressure results highlights the success of TIP4P-Ew in describing the energetic and entropic aspects of intermolecular interactions in liquid water. PMID:16321097

Horn, Hans W; Swope, William C; Pitera, Jed W

2005-11-15

318

Condensation of water vapor: Experimental determination of mass and thermal accommodation coefficients  

NASA Astrophysics Data System (ADS)

Experimental determinations of mass and thermal accommodation coefficients ?m and ?t for condensation of water vapor in air have been conducted covering a temperature range from about 250 to 290 K. For the first time, both coefficients have been determined directly and simultaneously. To this end, growth of water droplets in air has been observed at different total gas pressures ranging from about 1000 down to 100 hPa. Monodispersed seed particles have been used as condensation nuclei. After addition of water vapor with well-defined partial vapor pressure, supersaturation was achieved by adiabatic expansion in an expansion chamber. Most experiments reported in the present paper were performed at vapor saturation ratios ranging from 1.30 to 1.50. Monodispersed Ag particles with a diameter of 9 nm have been used as condensation nuclei, and for humidification a diffusion humidifier was applied. One experiment was performed at the saturation ratio of 1.02, which resembles conditions observed in the Earth's lower atmosphere. In this experiment, monodispersed DEHS particles with a diameter of 80 nm were used as condensation nuclei, and water vapor was generated by quantitative evaporation of a liquid jet. Droplet growth was monitored using the CAMS method. For determination of the accommodation coefficients, experimental droplet growth curves were compared to corresponding theoretical curves. Quantitative comparison was performed by varying the respective accommodation coefficient and the starting time of droplet growth in a two-parameter best fit procedure. Considering the uncertainty with respect to the starting time of droplet growth and the uncertainties of the experimental water vapor supersaturation, corresponding maximum errors have been determined. From the results obtained it can be stated that ?t is larger than 0.85 over the whole considered temperature range. For 250-270 K, values of ?m below 0.8 are excluded, and for higher temperatures up to 290 K we can exclude values of ?m below 0.4. Both coefficients are likely to be unity for all studied conditions. The results of this study enable accurate predictions of the formation and growth of cloud droplets required to parameterize cloud light scattering/absorption and precipitation properties in climate models.

Winkler, P. M.; Vrtala, A.; Rudolf, R.; Wagner, P. E.; Riipinen, I.; Vesala, T.; Lehtinen, K. E. J.; Viisanen, Y.; Kulmala, M.

2006-10-01

319

Oxidation of Ultra High Temperature Ceramics in Water Vapor  

NASA Technical Reports Server (NTRS)

Ultra High Temperature Ceramics (UHTCs) including HfB2 + 20v/0 SiC (HS), ZrB2 + 20v/0 SiC (ZS), and ZrB2 + 30v/0 C + 14v/0 SiC (ZCS) have been investigated for use as potential aeropropulsion engine materials. These materials were oxidized in water vapor (90 percent) using a cyclic vertical furnace at 1 atm. The total exposure time was 10 h at temperatures of 1200, 1300, and 1400 C. CVD SiC was also evaluated as a baseline for comparison. Weight change, X-ray diffraction analyses, surface and cross-sectional SEM and EDS were performed. These results are compared with tests ran in a stagnant air furnace at temperatures of 1327 C for 100 min, and with high pressure burner rig (HPBR) results at 1100 and 1300 C at 6 atm for 50 h. Low velocity water vapor does not make a significant contribution to the oxidation rates of UHTCs when compared to stagnant air. The parabolic rate constants at 1300 C, range from 0.29 to 16.0 mg(sup 2)cm(sup 4)/h for HS and ZCS, respectively, with ZS results between these two values. Comparison of results for UHTCs tested in the furnace in 90 percent water vapor with HPBR results was difficult due to significant sample loss caused by spallation in the increased velocity of the HPBR. Total recession measurements are also reported for the two test environments.

Nguyen, QuynhGiao N.; Opila, Elizabeth J.; Robinson, Raymond C.

2004-01-01

320

An optical water vapor sensor for unmanned aerial vehicles  

SciTech Connect

The water vapor sensor developed by Aerodyne Research, based on the optical absorption of light at {approximately}935 nm, has been successfully demonstrated on board the Pacific Northwest National Laboratory's Gulfstream-1 research aircraft during the Department of Energy's ARM Intensive Operations Period in August 1998. Data taken during this field campaign show excellent agreement with a chilled mirror and Lyman-alpha hygrometers and measurements confirm the ability to measure rapid, absolute water vapor fluctuations with a high degree of instrument stability and accuracy, with a noise level as low 10 ppmv (1 Hz measurement bandwidth). The construction of this small, lightweight sensor contains several unique elements which result in several significant advantages when compared to other techniques. First, the low power consumption Argon discharge lamp provides an optical beam at a fixed wavelength without a need for temperature or precision current control. The multi-pass absorption cell developed for this instrument provides a compact, low cost method that can survive deployment in the field. Fiber-optic cables, which are used to convey to light between the absorption cell, light source, and detection modules enable remote placement of the absorption cell from the opto-electronics module. Finally, the sensor does not use any moving parts which removes a significant source of potential malfunction. The result is an instrument which maintained its calibration throughout the field measurement campaign, and was not affected by high vibration and large uncontrolled temperature excursions. We believe that the development of an accurate, fast response water vapor monitor described in this report will open up new avenues of aerial-vehicle-based atmospheric research which have been relatively unexplored due to the lack of suitable low-cost, light-weight instrumentation.

Timothy A. Berkoff; Paul L. Kebabian; Robert A. McClatchy; Charles E. Kolb; Andrew Freedman

1998-12-01

321

Titanium Dioxide Volatility in High Temperature Water Vapor  

NASA Technical Reports Server (NTRS)

Titanium (Ti) containing materials are of high interest to the aerospace industry due to its high temperature capability, strength, and light weight. As with most metals an exterior oxide layer naturally exists in environments that contain oxygen (i.e. air). At high temperatures, water vapor plays a key role in the volatility of materials including oxide surfaces. This study will evaluate cold pressed titanium dioxide (TiO2) powder pellets at a temperature range of 1400 C - 1200 C in water containing environments to determine the volatile hydroxyl species using the transpiration method. The water content ranged from 0-76 mole% and the oxygen content range was 0-100 mole % during the 20-250 hour exposure times. Preliminary results indicate that oxygen is not a key contributor at these temperatures and the following reaction is the primary volatile equation for all three temperatures: TiO2 (s) + H2O (g) = TiO(OH)2 (g).

Nguyen, QynhGiao N.

2008-01-01

322

Oxidation of Carbon Fibers in Water Vapor Studied  

NASA Technical Reports Server (NTRS)

T-300 carbon fibers (BP Amoco Chemicals, Greenville, SC) are a common reinforcement for silicon carbide composite materials, and carbon-fiber-reinforced silicon carbide composites (C/SiC) are proposed for use in space propulsion applications. It has been shown that the time to failure for C/SiC in stressed oxidation tests is directly correlated with the fiber oxidation rate (ref. 1). To date, most of the testing of these fibers and composites has been conducted in oxygen or air environments; however, many components for space propulsion, such as turbopumps, combustors, and thrusters, are expected to operate in hydrogen and water vapor (H2/H2O) environments with very low oxygen contents. The oxidation rate of carbon fibers in conditions representative of space propulsion environments is, therefore, critical for predicting component lifetimes for real applications. This report describes experimental results that demonstrate that, under some conditions, lower oxidation rates of carbon fibers are observed in water vapor and H2/H2O environments than are found in oxygen or air. At the NASA Glenn Research Center, the weight loss of the fibers was studied as a function of water pressure, temperature, and gas velocity. The rate of carbon fiber oxidation was determined, and the reaction mechanism was identified.

Opila, Elizabeth J.

2003-01-01

323

Deuterium in water vapor evaporated from a coastal salt marsh  

NASA Astrophysics Data System (ADS)

Atmospheric water vapor was sampled simultaneously at two heights in the atmospheric surface layer above a coastal salt marsh near New Haven, Connecticut, during June 11-27, 1997. The water vapor samples were analyzed for their mixing ratio, Q, and deuterium isotope ratio, ?D. The observed ?D varied in the range of -145 to -89 per mil and was positively correlated with Q, reflecting the influence of in-cloud condensation and surface evapotranspiration processes at a regional scale. Both Q and ?D were, in general, lower at the upper level, indicating an upward transport of H216O and HD16O. The Craig-Gordon model reproduced reasonably well the combined effects of equilibrium and kinetic fractionations and atmospheric demand on the evaporation process. Transpiration of the marsh plants, Spartina patens (Ait.), was a minor component (11%) of the total evapotranspiration during the experimental period. We also suggest that the relationship between ?D and salinity, S, of the marsh surface water can be used to infer the isotope flux ratio. More data, however, are needed to verify this mass balance approach.

He, Hui; Lee, Xuhui; Smith, Ronald B.

2001-06-01

324

Isobaric vapor-liquid equilibria for methanol + ethanol + water and the three constituent binary systems  

Microsoft Academic Search

Vapor-liquid equilibrium data for methanol + ethanol + water and its three constituent binary systems methanol + ethanol, ethanol + water, and methanol + water were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental binary data were correlated by the NRTL equation. The ternary system methanol + ethanol + water was predicted by means of the

Kiyofumi Kurihara; Mikiyoshi Nakamichi; Kazuo Kojima

1993-01-01

325

Sensing integrated water vapor along GPS ray paths  

NASA Astrophysics Data System (ADS)

We demonstrate sensing of integrated slant-path water vapor (SWV) along ray paths between Global Positioning System (GPS) satellites and receivers. We use double differencing to remove GPS receiver and satellite clock errors and 85-cm diameter choke ring antennas to reduce ground-reflected multipath. We compare more than 17,000 GPS and pointed radiometer double difference observations above 20° elevation and find 1.3 mm rms agreement. Potential applications for SWV data include local and regional weather modeling and prediction, correction for slant wet delay effects in GPS surveying and orbit determination, and synthetic aperture radar (SAR) imaging. The method is viable during all weather conditions.

Ware, Randolph; Alber, Chris; Rocken, Christian; Solheim, Fredrick

326

Nd:Glass-Raman laser for water vapor dial  

NASA Technical Reports Server (NTRS)

A tunable solid-state Raman shifted laser which was used in a water vapor Differential Absorption Lidar (DIAL) system at 9400 A is described. The DIAL transmitter is based on a tunable glass laser operating at 1.06 microns, a hydrogen Raman cell to shift the radiation to 1.88 microns, and a frequency doubling crystal. The results of measurements which characterize the output of the laser with respect to optimization of optical configuration and of Raman parameters were reported. The DIAL system was also described and preliminary atmospheric returns shown.

Kagann, R. H.; Petheram, J. C.; Rosenberg, A.

1986-01-01

327

6.3-micron water-vapor-band derivatives  

NASA Technical Reports Server (NTRS)

Measurement of the absorptance in the 6.3-micron band of a 1-m column of water vapor as a function of concentration c, pressure p, and temperature T. From the measured absorptance, the first derivatives with respect to c, p, and T, as well as the second derivatives with respect to cc, pp, cp, and pT have been obtained. These experimental results have been compared with values calculated from the line parameters of the 720 strongest rotational lines in the band.

Hendrickson, P. E.; Walls, W. L.; Broersma, S.

1974-01-01

328

Water Vapor Winds and Their Application to Climate Change Studies  

NASA Technical Reports Server (NTRS)

The retrieval of satellite-derived winds and moisture from geostationary water vapor imagery has matured to the point where it may be applied to better understanding longer term climate changes that were previously not possible using conventional measurements or model analysis in data-sparse regions. In this paper, upper-tropospheric circulation features and moisture transport covering ENSO periods are presented and discussed. Precursors and other detectable interannual climate change signals are analyzed and compared to model diagnosed features. Estimates of winds and humidity over data-rich regions are used to show the robustness of the data and its value over regions that have previously eluded measurement.

Jedlovec, Gary J.; Lerner, Jeffrey A.

2000-01-01

329

Raman-shifted dye laser for water vapor DIAL measurements  

NASA Astrophysics Data System (ADS)

For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, narrowband (about 0.03/cm) laser radiation at 720- and 940-nm wavelengths was generated by stimulated Raman scattering (SRS), using the narrow linewidth (about 0.02/cm) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20 percent and 35 percent, when using a conventional and waveguide Raman cell, respectively. The linewidth of the first Stokes line at high cell pressures, and the inferred collisional broadening coefficients, agree well with those previously measured in spontaneous Raman scattering.

Grossmann, B. E.; Singh, U. N.; Cotnoir, L. J.; Wilkerson, T. D.; Higdon, N. S.; Browell, E. V.

1987-05-01

330

Raman-shifted dye laser for water vapor DIAL measurements.  

PubMed

For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, we have generated narrowband (~0.03-cm(-1)) laser radiation at 720- and 940-nm wavelengths by stimulated Raman scattering (SRS) using the narrow linewidth (~0.02-cm(-1)) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20% and 35% when using a conventional and waveguide Raman cell, respectively. We measured the linewidth of the first Stokes line at high cell pressures and inferred collisional broadening coefficients that agree well with those previously measured in spontaneous Raman scattering. PMID:20454378

Grossmann, B E; Singh, U N; Higdon, N S; Cotnoir, L J; Wilkerson, T D; Browell, E V

1987-05-01

331

Raman-shifted dye laser for water vapor DIAL measurements  

NASA Technical Reports Server (NTRS)

For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, narrowband (about 0.03/cm) laser radiation at 720- and 940-nm wavelengths was generated by stimulated Raman scattering (SRS), using the narrow linewidth (about 0.02/cm) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20 percent and 35 percent, when using a conventional and waveguide Raman cell, respectively. The linewidth of the first Stokes line at high cell pressures, and the inferred collisional broadening coefficients, agree well with those previously measured in spontaneous Raman scattering.

Grossmann, B. E.; Singh, U. N.; Cotnoir, L. J.; Wilkerson, T. D.; Higdon, N. S.; Browell, E. V.

1987-01-01

332

Investigation of the CARS spectrum of water vapor  

NASA Technical Reports Server (NTRS)

The dependence of the coherent anti-Stokes Raman (CARS) spectrum of water vapor on temperature has been measured and compared with CARS spectral model calculations to permit diagnostics of this important combustion product. Measurements have been made in a methane-air flame at 1700 K and in a heated cell, maintained at atmospheric pressure and temperatures between 310 K and 710 K. The agreement between measured and calculated spectra is very good. The importance of assumed Raman linewidth is shown to be critical to the calculation of spectral features near the band head of measured spectra.

Shirley, J. A.; Hall, R. J.; Eckbreth, A. C.

1981-01-01

333

Paralinear Oxidation of CVD SiC in Water Vapor  

NASA Technical Reports Server (NTRS)

The oxidation kinetics of CVD SiC were monitored by thermogravimetric analysis (TGA) in a 50% H2O/50% O2 gas mixture flowing at 4.4 cm/s for temperatures between 1200 and 1400 C. Paralinear weight change kinetics were observed as the water vapor oxidized the SiC and simultaneously volatilized the silica scale. The long-term degradation rate of SiC is determined by the volatility of the silica scale. Rapid SiC surface recession rates were estimated from these data for actual aircraft engine combustor conditions.

Opila, Elizabeth J.; Hann, Raiford E., Jr.

1997-01-01

334

An alexandrite regenerative amplifier for water vapor and temperature measurements  

NASA Technical Reports Server (NTRS)

The Differential Absorption Lidar (DIAL) technique is a powerful method for determining meteorological parameters, but it requires high quality of the laser source: high energy, very narrow bandwidth, high wavelength stability, and spectral purity. Although many efforts have been made to improve the lasers in view of these aspects, a satisfactory solution has not been demonstrated up to now. We describe a regenerative amplifier, using a Ti:sapphire laser as master oscillator and an alexandrite laser as slave amplifier, which is expected to meet the requirements for water vapor concentration and temperature measurements.

Thro, P.-Y.; Boesenberg, J.; Wulfmeyer, V.

1992-01-01

335

Carbon dioxide and water vapor high temperature electrolysis  

NASA Technical Reports Server (NTRS)

The design, fabrication, breadboard testing, and the data base obtained for solid oxide electrolysis systems that have applications for planetary manned missions and habitats are reviewed. The breadboard tested contains sixteen tubular cells in a closely packed bundle for the electrolysis of carbon dioxide and water vapor. The discussion covers energy requirements, volume, weight, and operational characteristics related to the measurement of the reactant and product gas compositions, temperature distribution along the electrolyzer tubular cells and through the bundle, and thermal energy losses. The reliability of individual cell performance in the bundle configuration is assessed.

Isenberg, Arnold O.; Verostko, Charles E.

1989-01-01

336

Multispectral atmospheric mapping sensor of mesoscale water vapor features  

NASA Technical Reports Server (NTRS)

The Multispectral atmospheric mapping sensor was checked out for specified spectral response and detector noise performance in the eight visible and three infrared (6.7, 11.2, 12.7 micron) spectral bands. A calibration algorithm was implemented for the infrared detectors. Engineering checkout flights on board the ER-2 produced imagery at 50 m resolution in which water vapor features in the 6.7 micron spectral band are most striking. These images were analyzed on the Man computer Interactive Data Access System (McIDAS). Ground truth and ancillary data was accessed to verify the calibration.

Menzel, P.; Jedlovec, G.; Wilson, G.; Atkinson, R.; Smith, W. (w4560409)

1985-01-01

337

Interactions of Water Vapor with Oxides at Elevated Temperatures  

NASA Technical Reports Server (NTRS)

Many volatile metal hydroxides form by reaction of the corresponding metal oxide with water vapor. These reactions are important in a number of high temperature corrosion processes. Experimental methods for studying the thermodynamics of metal hydroxides include: gas leak Knudsen cell mass spectrometry, free jet sampling mass spectrometry, transpiration and hydrogen-oxygen flame studies. The available experimental information is reviewed and the most stable metal hydroxide species are correlated with position in the periodic table. Current studies in our laboratory on the Si-O-H system are discussed.

Jacobson, Nathan; Opila, Elizabeth; Copland, Evan; Myers, Dwight

2003-01-01

338

Final Report for ARM Project Measuring 4-D Water Vapor Fields with GPS  

SciTech Connect

Water vapor is a primary element in the Earth’s climate system. Atmospheric water vapor is central to cloud processes, radiation transfer, and the hydrological cycle. Using funding from Department of Energy (DOE) grant DE-FG03-02ER63327, the University Corporation for Atmospheric Research (UCAR) developed new observational techniques to measure atmospheric water vapor and applied these techniques to measure four dimensional water vapor fields throughout the United States Southern Great Plains region. This report summarizes the development of a new observation from ground based Global Positioning System (GPS) stations called Slant Water Vapor (SW) and it’s utilization in retrieving four dimensional water vapor fields. The SW observation represents the integrated amount of water vapor between a GPS station and a transmitting satellite. SW observations provide improved temporal and spatial sampling of the atmosphere when compared to column-integrated quantities such as preciptitable water vapor (PW). Under funding from the DOE Atmospheric Radiation Measurement (ARM) program, GPS networks in the Southern Great Plains (SGP) region were deployed to retrieve SW to improve the characterization of water vapor throughout the region. These observations were used to estimate four dimensional water vapor fields using tomographic approaches and through assimilation into the MM5 numerical weather model.

Braun, John

2006-02-06

339

CHARM: A CubeSat Water Vapor Radiometer for Earth Science  

NASA Technical Reports Server (NTRS)

The Jet Propulsion Laboratory (JPL) and Ames Research Center (ARC) are partnering in the CubeSat Hydrometric Atmospheric Radiometer Mission (CHARM), a water vapor radiometer integrated on a 3U CubeSat platform, selected for implementation under NASA Hands-On Project Experience (HOPE-3). CHARM will measure 4 channels at 183 GHz water vapor line, subsets of measurements currently performed by larger and more costly spacecraft (e.g. ATMS, AMSU-B and SSMI/S). While flying a payload that supports SMD science objectives, CHARM provides a hands-on opportunity to develop technical, leadership, and project skills. CHARM will furthermore advance the technology readiness level (TRL) of the 183 GHz receiver subsystem from TRL 4 to TRL 6 and the CubeSat 183 GHz radiometer system from TRL 4 to TRL 7.

Lim, Boon; Mauro, David; DeRosee, Rodolphe; Sorgenfrei, Matthew; Vance, Steve

2012-01-01

340

Stability of evaporating water when heated through the vapor and the liquid phases.  

PubMed

The stability of a water layer of uniform thickness held in a two-dimensional container of finite or semi-infinite extent is examined using linear stability theory. The liquid-vapor interface can be heated both through the liquid and through the vapor, as previously experimentally reported. The need to introduce a heat transfer coefficient is eliminated by introducing statistical rate theory (SRT) to predict the evaporation flux. There are no fitting or undefined parameters in the expression for the evaporation flux. The energy transport is parametrized in terms of the evaporation number, Eev, that for a given experimental circumstance can be predicted. The critical Marangoni number for the finite, Macf, and for the semi-infinite system, Mac(infinity), can be quantitatively predicted. Experiments in which water evaporated from a stainless-steel funnel and from a polymethyl methacrylate (PMMA) funnel into its vapor have been previously reported. Marangoni convection was observed in the experiments that used the stainless-steel funnel but not with the PMMA funnel even though the Marangoni number for the PMMA funnel was more than 27,000. The SRT-based stability theory indicates that the critical value of the Marangoni number for the experiments with the PMMA funnel was greater than the experimental value of the Marangoni number in each case; thus, no Marangoni convection was predicted to result from an instability. The observed convection with the stainless-steel funnel resulted from a temperature gradient imposed along the interface. PMID:20365865

Das, Kausik S; MacDonald, Brendan D; Ward, C A

2010-03-01

341

Temporal and spatial relationships between topography, atmospheric water vapor, liquid water and vegetation endmember fractions determined using AVIRIS  

Microsoft Academic Search

Temporal and spatial changes in water vapor, liquid water and endmember fractions were investigated using AVIRIS data collected in the vicinity of Jasper Ridge, CA, on three dates in 1992. Water vapor and liquid water were mapped using a Modtran-II based atmospheric model that accounts for spatially varying atmospheric properties. Spectral mixture analysis (SMA) was used to model vegetation as

D. A. Roberts; R. O. Green; J. B. Adams; J. S. Cothern; D. E. Sabol; M. O. Smith

1994-01-01

342

Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts  

NASA Technical Reports Server (NTRS)

These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation. The assimilation of satellite-observed moisture and cloud water, together withy three-mode diabatic initialization, significantly alleviates the model precipitation spinup problem, especially in the first 3 h of the forecast. Experimental forecasts indicate that the impact of satellite-observed temperature and water vapor profiles and cloud water alone in the initialization procedure shortens the spinup time for precipitation rates by 1-2 h and for regeneration of the areal coverage by 3 h. The diabatic initialization further reduces the precipitation spinup time (compared to adiabatic initialization) by 1 h.

Wu, Xiaohua; Diak, George R.; Hayden, Cristopher M.; Young, John A.

1995-01-01

343

Ground-based lidar measurements of ozone, water vapor, and aerosols in the lower stratosphere and troposphere  

SciTech Connect

Lidar measurements of ozone and water vapor concentrations were performed during several field experiments in 1980-1981 by means of the differential absorption laser technique. Profiles up to 26 km for ozone and up to 9 km for water vapor are presented. Also, a lidar survey of aerosol layers ranging from 12 to 23 km were performed following the Mt. St. Helens major eruption (May 1980). Experiments were conducted at the CNRS lidar facility of the Haute Provence Observatory which is located in southern France (44/sup 0/N, 5/sup 0/E). For ozone a vertical profile is recorded in three sequences, each requiring 15 min of acquisition time. The relative accuracy is better than 5% at the lower altitude and falls to 20% at 25 km. For water vapor the time sequences are 4 min or 8 min long and the accuracy is better than 10% in the lower troposphere.

Flamant, P.H. (Jet Propulsion Lab., Pasadena, CA; CNRS, Laboratoire de Meteorologie Dynamique, Palaiseau, Essonne, France); Pelon, J. (CNRS, Service d'Aeronomie, Verrieres-le-Buisson, Essonne, France); Lefrere, J. (Electricite de France, Direction des Etudes et Recherches, Chatou, Yvelines, France)

1982-01-01

344

Ground-based lidar measurements of ozone, water vapor and aerosols in the lower stratosphere and troposphere  

NASA Technical Reports Server (NTRS)

Lidar measurements of ozone and water vapor concentrations were performed during several field experiments in 1980-1981 by means of the differential absorption laser technique. Profiles up to 26 km for ozone and up to 9 km for water vapor are presented. Also, a lidar survey of aerosol layers ranging from 12 to 23 km were performed following the Mt. St. Helens major eruption (May 1980). Experiments were conducted at the CNRS lidar facility of the Haute Provence Observatory which is located in southern France (44 deg N, 5 deg E). For ozone a vertical profile is recorded in three sequences, each requiring 15 min of acquisition time. The relative accuracy is better than 5 percent at the lower altitude and falls to 20 percent at 25 km. For water vapor the time sequences are 4 min or 8 min long and the accuracy is better than 10 percent in the lower troposphere.

Flamant, P. H.; Pelon, J.; Lefrere, J.; Megie, G.; Cahen, C.

1982-01-01

345

On the relationship between water vapor over the oceans and sea surface temperature  

NASA Technical Reports Server (NTRS)

Monthly mean precipitable water data obtained from passive microwave radiometry were correlated with the National Meteorological Center (NMC) blended sea surface temperature data. It is shown that the monthly mean water vapor content of the atmosphere above the oceans can generally be prescribed from the sea surface temperature with a standard deviation of 0.36 g/sq cm. The form of the relationship between precipitable water and sea surface temperature in the range T (sub s) greater than 18 C also resembles that predicted from simple arguments based on the Clausius-Clapeyron relationship. The annual cycle of the globally integrated mass of Scanning Multichannel Microwave Radiometer (SMMR) water vapor is shown to differ from analyses of other water vapor data in both phase and amplitude and these differences point to a significant influence of the continents on water vapor. Regional scale analyses of water vapor demonstrate that monthly averaged water vapor data, when contrasted with the bulk sea surface temperature relationship developed in this study, reflect various known characteristics of the time mean large-scale circulation over the oceans. A water vapor parameter is introduced to highlight the effects of large-scale motion on atmospheric water vapor. Based on the magnitude of this parameter, it is shown that the effects of large-scale flow on precipitable water vapor are regionally dependent, but for the most part, the influence of circulation is generally less than about + or - 20 percent of the seasonal mean.

Stephens, Graeme L.

1990-01-01

346

Preprototype vapor compression distillation subsystem. [recovering potable water from wastewater  

NASA Technical Reports Server (NTRS)

A three-person capacity preprototype vapor compression distillation subsystem for recovering potable water from wastewater aboard spacecraft was designed, assembled, and tested. The major components of the subsystem are: (1) a distillation unit which includes a compressor, centrifuge, central shaft, and outer shell; (2) a purge pump; (3) a liquids pump; (4) a post-treat cartridge; (5) a recycle/filter tank; (6) an evaporator high liquid level sensor; and (7) the product water conductivity monitor. A computer based control monitor instrumentation carries out operating mode change sequences, monitors and displays subsystem parameters, maintains intramode controls, and stores and displays fault detection information. The mechanical hardware occupies 0.467 m3, requires 171 W of electrical power, and has a dry weight of 143 kg. The subsystem recovers potable water at a rate of 1.59 kg/hr, which is equivalent to a duty cycle of approximately 30% for a crew of three. The product water has no foul taste or odor. Continued development of the subsystem is recommended for reclaiming water for human consumption as well as for flash evaporator heat rejection, urinal flushing, washing, and other on-board water requirements.

Ellis, G. S.; Wynveen, R. A.; Schubert, F. H.

1979-01-01

347

Micropulse water vapor differential absorption lidar: transmitter design and performance.  

PubMed

An all diode-laser-based micropulse differential absorption lidar (DIAL) laser transmitter for tropospheric water vapor and aerosol profiling is presented. The micropulse DIAL (MPD) transmitter utilizes two continuous wave (cw) external cavity diode lasers (ECDL) to seed an actively pulsed, overdriven tapered semiconductor optical amplifier (TSOA). The MPD laser produces up to 7 watts of peak power over a 1 µs pulse duration (7 µJ) and a 10 kHz pulse repetition frequency. Spectral switching between the online and offline seed lasers is achieved on a 1Hz basis using a fiber optic switch to allow for more accurate sampling of the atmospheric volume between the online and offline laser shots. The high laser spectral purity of greater than 0.9996 coupled with the broad tunability of the laser transmitter will allow for accurate measurements of tropospheric water vapor in a wide range of geographic locations under varying atmospheric conditions. This paper describes the design and performance characteristics of a third generation MPD laser transmitter with enhanced laser performance over the previous generation DIAL system. PMID:23187280

Nehrir, Amin R; Repasky, Kevin S; Carlsten, John L

2012-10-22

348

Isobaric vapor–liquid and vapor–liquid–liquid equilibrium data for the water–ethanol–hexane system  

Microsoft Academic Search

Isobaric vapor–liquid and vapor–liquid–liquid equilibria were measured for the water–ethanol–hexane system at normal atmospheric pressure. The apparatus used for the determination of vapor–liquid–liquid equilibrium data was an all-glass dynamic recirculating still with an ultrasonic homogenizer coupled to the boiling flask.The experimental data demonstrated the existence of a ternary heterogeneous azeotrope at 329.2K with a composition of 0.105, 0.236 and 0.658mol

V. Gomis; R. Pedraza; M. D. Saquete

2007-01-01

349

Microstructure and water vapor transport properties of temperature sensitive polyurethanes  

NASA Astrophysics Data System (ADS)

Temperature sensitive polyurethane (TS-PU) is one novel type of smart polymers. The water vapor permeability (WVP) of its membrane could undergo a significant increase as temperature increases within a predetermined temperature range. Such smart property enables this material to have a broad range of potential applications to textile industry, medicine, environmental fields and so on. However, based on the literature review, contradicting results were found on some TS-PUs. The aims of this project are to synthesize TS-PU with Tm in the broader temperature range including ambient temperature range, and then investigate systematically the relationships between microstructure and water vapor transport properties of TS-PU. For this purpose, in this project, a series of polyurethanes (PU) were synthesized using five different crystalline polyols with approximately similar molecule weight and three different hydrophilic contents, and dense membranes were prepared accordingly. The microstructure and properties of these PUs were investigated using DSC, WAXD, DMA, FTIR, GPC, POM, TEM, SEM and PALS. Their equilibrium water sorption and water vapor permeability were measured accordingly. Results show that crystal melting of these resulting PUs take place in the temperature range from -10--60°C as desired. Storage modulus (E') drops down quickly in the temperature range of crystal melting, suggesting a great transition in the predetermined temperature range. The decreased HSC as well as regular chemical structure of polyols results in the larger spherulites and higher melting end temperature, and the higher crystallinity induces the more obvious incompatibility of soft segment and hard segment in the PUs. These PUs are proved to have good enough tensile properties for textile application. The mean free volume size and fractional free volume increase more significantly in the temperature range of crystal melting than in other temperature intervals. Finally, as expected, the WVP of semi-crystalline PU membranes increases significantly in the temperature range of crystal melting. Equilibrium water sorption keeps approximately constant. The significant increase in WVP of semi-crystalline PU is obviously correlated with the sharp increase in the free volume in the predetermined temperature range.

Ding, Xuemei

350

Continuous on-line water vapor isotope measurements in Antarctica  

NASA Astrophysics Data System (ADS)

In the context of a globally warming climate it is crucial to study the climate variability in the past and to understand the underlying mechanisms (1). Precipitation deposited on the polar ice caps provides a means to retrieve information on temperature changes (through the paleo-temperature dependence of the isotopic composition of the ice) and atmospheric composition (of gas stored in bubbles in the ice) on time scales from one to almost one million years, with sub-annual resolution in the most recent centuries. However, it is now widely recognized that the calibration of the paleo-thermometer is highly problematic. For this reason attempts to model the global water cycle, including the isotope signals, are ongoing with the aim of providing a more physical basis of the isotope - temperature relation. Currently, there is a large divergence in the results obtained by different modeling strategies. The missing link in these model studies is their forcing by experimental data on the pre-deposition isotopic composition of the vapor phase compartment of the hydrological cycle. We propose to measure the isotopic composition of moisture carried towards and deposited on Antarctica, in order to constrain the numerical models. In this context we are developing a modified, more sensitive and precise, version of a laser water vapor isotope spectrometer, originally designed for stratospheric studies (2, 3). This instrument, which will first be operated at the Norwegian station of Troll in Queen Maud Land, will enable the continuous, online measurement of all three stable isotope ratios of atmospheric water vapor. So far, such data is non-existent. Our data should improve the validity of the models and improve the understanding of the physical mechanisms at the basis of the isotope thermometer. This in turn will lead to an increased confidence in the predictions of (general circulation) models concerning climate variability. (1) International Panel on Climate Change (IPCC), 4th Assessment Report, Chapters 1 and 6 (2007). (2) E.R.T. Kerstel, R.Q. Iannone, M. Chenevier, S. Kassi, H.-J. Jost, and D. Romanini, A water isotope (2H, 17O, and 18O) spectrometer based on optical-feedback cavity enhanced absorption for in-situ airborne applications, Appl. Phys. B 85(2-3), 397-406 (2006). (3) R.Q. Iannone, S. Kassi, H.-J. Jost, M. Chenevier, D. Romanini, H.A.J. Meijer, S. Dhaniyala, M. Snels, and E.R.Th. Kerstel, Development and airborne operation of a compact water isotope ratio spectrometer, Isotop. Environm. Health Studies 45 (JESIUM 2008 special issue), 1-18 iFirst (2009). doi=10.1080/10256010903172715

Landsberg, Janek; Romanini, Daniele; Holmen, Kim; Isaksson, Elisabeth; Meijer, Harro; Kerstel, Erik

2010-05-01

351

Modeling Convection of Water Vapor into the Mid-latitude Stratosphere  

NASA Astrophysics Data System (ADS)

The direct injection of water vapor into the mid-latitude stratosphere by moist convection during the North American monsoon has been observed in isotopic data (Hanisco et al. 2007). The consequent elevated levels of stratospheric water vapor may lead to catalytic destruction of stratospheric ozone in the mid-latitudes thereupon resulting in increased UV exposure at the Earth's surface and increased risk to public health (Anderson et al. 2012). Climate models, however, do not directly inject water into the mid-latitude stratosphere by convection and so are not useful tools for predicting trends in mid-latitude water vapor. To address this issue, we undertook a modeling study to investigate the convective injection of water vapor from the troposphere into the stratosphere in the mid-latitudes. We used the Advanced Research Weather and Research Forecasting (ARW) model at a 3-km resolution to resolve convection over the eastern United States during August of 2007. In our simulations we observed ~4 instances of injection of water vapor up to 70 hPa associated with mesoscale convective systems. Animations of these events showed that the morphology of the injected water vapor depends strongly on stratospheric level. Histograms of model output water vapor are consistent with MLS water vapor data. As a control we also performed a simulation of the Indian monsoon which had much less injection of water vapor into the stratosphere during the same time period. The development of modeling of water vapor convective injection may indicate a potential to use ARW as a means to predict isotopic fractionation of water vapor in the stratosphere and interdecadal variability of stratospheric ozone in the mid-latitudes. Water Vapor Concentration at 100 hPa at 3 A.M. August 21, 2007.

Clapp, C.; Leroy, S. S.; Anderson, J. G.

2013-12-01

352

IASI temperature and water vapor retrievals - error assessment and validation  

NASA Astrophysics Data System (ADS)

The METOP-A satellite Infrared Atmospheric Sounding Interferometer (IASI) Level 2 products comprise retrievals of vertical profiles of temperature and water vapor. The error covariance matrices and biases of the most recent version (4.3.1) of the L2 data were assessed, and the assessment was validated using radiosonde data for reference. The radiosonde data set includes dedicated and synoptic time launches at the Lindenberg station in Germany. For optimal validation, the linear statistical Validation Assessment Model (VAM) was used. The VAM uses radiosonde profiles as input and provides optimal estimate of the nominal IASI retrieval by utilizing IASI averaging kernels and statistical characteristics of the ensembles of the reference radiosondes. For temperatures above 900 mb and water retrievals above 700 mb, level expected and assessed errors are in good agreement. Below those levels, noticeable excess in assessed error is observed, possibly due to inaccurate surface parameters and undetected clouds/haze.

Pougatchev, N.; August, T.; Calbet, X.; Hultberg, T.; Oduleye, O.; Schlüssel, P.; Stiller, B.; St. Germain, K.; Bingham, G.

2009-09-01

353

IASI temperature and water vapor retrievals - error assessment and validation  

NASA Astrophysics Data System (ADS)

The METOP-A satellite Infrared Atmospheric Sounding Interferometer (IASI) Level 2 products comprise retrievals of vertical profiles of temperature and water vapor. The error covariance matrices and biases of the most recent version (4.3.1) of the L2 data were assessed, and the assessment was validated using radiosonde data for reference. The radiosonde data set includes dedicated and synoptic time launches at the Lindenberg station in Germany. For optimal validation, the linear statistical Validation Assessment Model (VAM) was used. The VAM uses radiosonde profiles as input and provides optimal estimate of the nominal IASI retrieval by utilizing IASI averaging kernels and statistical characteristics of the ensembles of the reference radiosondes. For temperature temperatures above 900 mb and water retrievals above 700 mb, level expected and assessed errors are in good agreement. Below those levels, noticeable excess in assessed error is observed, possibly due to inaccurate surface parameters and undetected clouds/haze.

Pougatchev, N.; August, T.; Calbet, X.; Hultberg, T.; Oduleye, O.; Schlüssel, P.; Stiller, B.; Germain, K. S.; Bingham, G.

2009-03-01

354

Temperature Dependences of Mechanisms Responsible for the Water Vapor Continuum  

NASA Astrophysics Data System (ADS)

The water-vapor continuum plays an important role in the radiation balance in the Earth's atmosphere. While this absorption has been known for a long time, the physical mechanism responsible is still an open problem. We have recently calculated theoretically both the magnitude and temperature dependence for the three mechanism that have been suggested: the far-wings of allowed lines, collision-induced absorption, and water dimers. All three mechanisms depend quadratically on the number density of H_2O for the self-continuum, and on the product of the densities for the foreign-continuum. However, these three mechanisms have quite differences on the temperature as we will discuss. This analysis may provide us with a method to assess their relative importance in ambient atmospheric measurements. Q. Ma, R. H. Tipping, and C. Leforestier, J. Chem. Phys. 128, 124313 (2008). C. Leforestier, R. H. Tipping, and Q. Ma, to be submitted for publication.

Ma, Q.; Tipping, R. H.; Leforestier, C.

2009-06-01

355

Alumina Volatility in Water Vapor at Elevated Temperatures: Application to Combustion Environments  

NASA Technical Reports Server (NTRS)

The volatility of alumina in high temperature water vapor was determined by measuring weight loss of sapphire coupons at temperatures between 1250 and 1500 C, water vapor partial pressures between 0.15 and 0.68 atm in oxygen, at one atmosphere total pressure, and a gas velocity of 4.4 centimeters per second. The variation of the volatility with water vapor partial pressure was consistent with Al(OH)3(g) formation. The enthalpy of reaction to form Al(OH)3(g) from alumina and water vapor was found to be 210 plus or minus 20 kJ/mol. Surface rearrangement of ground sapphire surfaces increased with water vapor partial pressure, temperature and volatility rate. Recession rates of alumina due to volatility were determined as a function of water vapor partial pressure and temperature to evaluate limits for use of alumina in long term applications in combustion environments.

Opila, Elizabeth J.; Myers, Dwight L.

2003-01-01

356

High pressure vapor-liquid and vapor-liquid-liquid equilibria for systems containing supercritical carbon dioxide, water and furfural  

Microsoft Academic Search

We measured vapor-liquid equilibrium for a binary system CO2?furfural at temperatures of 303 and 323 K and vapor-liquid-liquid equilibrium for a ternary system CO2?water?furfural at temperatures of 303, 323 and 343 K and pressure of 5 MPa to obtain fundamental data for concentration of furfural by using three phase separation technique. Furthermore the experimental data were compared with results calculated

Takeshi Sako; Tsutomu Sugeta; Noriaki Nakazawa; Katsuto Otake; Masahito Sato; Katsuo Ishihara; Masahiro Kato

1995-01-01

357

Processes Controlling Water Vapor in the Winter Arctic Stratospheric Middleworld  

NASA Technical Reports Server (NTRS)

Abstract: Water vapor in the winter arctic stratospheric middleworld (that part of the stratosphere with potential temperatures lower than the tropical tropopause) is important for two reasons: (1) the arctic middleworld is a source of air for the upper troposphere because of the generally downward motion, and thus its water vapor content helps determine upper tropospheric water, a critical part of the earth's radiation budget; and (2) under appropriate conditions, relative humidities will be large even to the point of stratospheric cirrus cloud formation, leading to the production of active chlorine species that could destroy ozone. On a number of occasions during SOLVE, clouds were observed in the stratospheric middleworld by the DC-8 aircraft. The relationship between ozone and CO from aircraft measurements taken during the early, middle and late part of the winter of 1999-2000 show that recent mixing with tropospheric air extends up to ozone values of about 350-450 ppbv. Above that level, the relationship suggests stratospheric air with minimal tropospheric influence. The transition is quite abrupt, particularly in early spring. Trajectory analyses are consistent with these relationships, with a significant drop-off in the percentage of trajectories with tropospheric PV values in their 10-day history as in-situ ozone increases above 400 ppbv. The water distribution is affected by these mixing characteristics, and by cloud formation. Significant cloud formation along trajectories occurs up to ozone values of about 400 ppbv during the early spring, with small, but nonzero probabilities extending to 550 ppbv. Cloud formation in the stratospheric middleworld is minimal during early and midwinter. Also important is the fact that, during early spring 30% of the trajectories near the tropopause (ozone values less than 200 ppbv) have minimum saturation mixing ratios less than 5 ppmv. Such parcels can mix out into the troposphere and could lead to very dry conditions in the upper troposphere at high latitudes during spring,

Pfister, Leonhard; Selkirk, Henry B.; Jensen, Eric J.; Podolske, James; Sachse, Glen; Avery, Melody; Schoeberl, Mark R.; Hipskind, R. Stephen (Technical Monitor)

2000-01-01

358

Adsorption of ethanol and water vapor by Silicalite, a hydrophobic molecular sieve  

Microsoft Academic Search

The molecular sieve Silicalite, which is known to selectively adsorb organic molecules from aqueous solutions, was studied to determine its capacity to adsorb mixtures of ethanol and water vapor. Measurements were made of the weight adsorbed from these vapors at isothermal, equilibrium conditions and at different pressures and temperatures. The work shows that the mass of vapor adsorbed is only

1982-01-01

359

What do instruments in NASA's A-Train reveal about regional trends in atmospheric water vapor?  

Microsoft Academic Search

Several instruments in NASA's A-Train satellite constellation are providing a 5+ year record of atmospheric water vapor and related quantities. Detecting climate-related changes in water vapor using these observations is challenging because trends may be caused by instrumental or other factors. We describe regional long-term variability in water vapor inferred from A-Train instruments, and relate those changes to known and

E. J. Fetzer; W. G. Read; S. L. Granger; M. de La Torre Juarez; F. W. Irion; B. H. Lambrigtsen; B. H. Kahn; V. T. Dang; D. E. Waliser

2008-01-01

360

Influences of friction drag on spontaneous condensation in water vapor supersonic flows  

Microsoft Academic Search

A mathematical model was developed to investigate the water vapor spontaneous condensation under supersonic flow conditions.\\u000a A numerical simulation was performed for the water vapor condensable supersonic flows through Laval nozzles under different\\u000a flow friction conditions. The comparison between numerical and experimental results shows that the model is accurate enough\\u000a to investigate the supersonic spontaneous condensation flow of water vapor

WenMing Jiang; ZhongLiang Liu; HengWei Liu; HuiZhong Pang; LingLing Bao

2009-01-01

361

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  

NASA Astrophysics Data System (ADS)

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).

Karpowicz, Bryan Mills

362

Study on the separation characteristics of tritiated water vapor adsorption-II.  

National Technical Information Service (NTIS)

In order to meet a small tritiated heavy water leakage in the heavy water nuclear reactor building, it is required to increase the sorption efficiency of adsorbent and sorption performance of the present heavy water vapor recovery system. Accordingly, the...

D. H. Ahn J. W. Na K. R. Kim K. W. Sung Y. E. Kim

1991-01-01

363

Cold Water Vapor in the Barnard 5 Molecular Cloud  

NASA Astrophysics Data System (ADS)

After more than 30 yr of investigations, the nature of gas-grain interactions at low temperatures remains an unresolved issue in astrochemistry. Water ice is the dominant ice found in cold molecular clouds; however, there is only one region where cold (~10 K) water vapor has been detected—L1544. This study aims to shed light on ice desorption mechanisms under cold cloud conditions by expanding the sample. The clumpy distribution of methanol in dark clouds testifies to transient desorption processes at work—likely to also disrupt water ice mantles. Therefore, the Herschel HIFI instrument was used to search for cold water in a small sample of prominent methanol emission peaks. We report detections of the ground-state transition of o-H2O (J = 110-101) at 556.9360 GHz toward two positions in the cold molecular cloud, Barnard 5. The relative abundances of methanol and water gas support a desorption mechanism which disrupts the outer ice mantle layers, rather than causing complete mantle removal.

Wirström, E. S.; Charnley, S. B.; Persson, C. M.; Buckle, J. V.; Cordiner, M. A.; Takakuwa, S.

2014-06-01

364

Numerical Analysis of Coupled Water, Vapor, and Heat Transport in the Vadose Zone  

Microsoft Academic Search

Vapor movement is often an important part in the total water flux in the vadose zone of arid or semiarid regions because the soil moisture is relatively low. The two major objectives of this study were to develop a numerical model in the HYDRUS-1D code that (i) solves the coupled equations governing liquid water, water vapor, and heat transport, together

Hirotaka Saito; Jiri Šim?nek; Binayak P. Mohanty

2006-01-01

365

Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts  

SciTech Connect

These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation.

Wu, X.; Diak, G.R.; Hayden, C.M.; Young, J.A. [Univ. of Wisconsin, Madison, WI (United States)] [Univ. of Wisconsin, Madison, WI (United States)

1995-02-01

366

Prediction of water vapor transport rates across polyvinylchloride packaging systems using a novel radiotracer method.  

PubMed

A radiotracer method is used to study the transport properties of water vapor in polyvinylchloride (PVC), a plastic commonly used in the packaging of parenteral solutions. Water vapor transport across a PVC film appears to be Fickian in nature. Using the steady-state solution of Fick's second law and the permeability coefficient of water vapor across the PVC film obtained using the described method, the predicted water vapor transport rate (WVTR) for a parenteral solution packaged in PVC is in reasonable agreement with actual WVTR as determined by weight loss under precisely controlled conditions. PMID:2250204

Wood, R W; Mulski, M J; Kuu, W Y

1990-01-01

367

Prediction of water vapor transport rates across polyvinylchloride packaging systems using a novel radiotracer method  

SciTech Connect

A radiotracer method is used to study the transport properties of water vapor in polyvinylchloride (PVC), a plastic commonly used in the packaging of parenteral solutions. Water vapor transport across a PVC film appears to be Fickian in nature. Using the steady-state solution of Fick's second law and the permeability coefficient of water vapor across the PVC film obtained using the described method, the predicted water vapor transport rate (WVTR) for a parenteral solution packaged in PVC is in reasonable agreement with actual WVTR as determined by weight loss under precisely controlled conditions.

Wood, R.W.; Mulski, M.J.; Kuu, W.Y. (Baxter Healthcare Corporation, Round Lake, IL (USA))

1990-09-01

368

Compact Water Vapor Exchanger for Regenerative Life Support Systems  

NASA Technical Reports Server (NTRS)

Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Regenerative CO2 removal systems are attractive for these missions because they do not use consumable CO2 absorbers. However, these systems also absorb and vent water to space along with carbon dioxide. This paper describes an innovative device designed to minimize water lost from regenerative CO2 control systems. Design studies and proof-of-concept testing have shown the feasibility of a compact, efficient membrane water vapor exchanger (WVX) that will conserve water while meeting challenging requirements for operation on future spacecraft. Compared to conventional WVX designs, the innovative membrane WVX described here has the potential for high water recovery efficiency, compact size, and very low pressure losses. The key innovation is a method for maintaining highly uniform flow channels in a WVX core built from water-permeable membranes. The proof-of-concept WVX incorporates all the key design features of a prototypical unit, except that it is relatively small scale (1/23 relative to a unit sized for a crew of six) and some components were fabricated using non-prototypical methods. The proof-of-concept WVX achieved over 90% water recovery efficiency in a compact core in good agreement with analysis models. Furthermore the overall pressure drop is very small (less than 0.5 in. H2O, total for both flow streams) and meets requirements for service in environmental control and life support systems on future spacecraft. These results show that the WVX provides very uniform flow through flow channels for both the humid and dry streams. Measurements also show that CO2 diffusion through the water-permeable membranes will have negligible effect on the CO2 partial pressure in the spacecraft atmosphere.

Izenson, Michael G.; Chen, Weibo; Anderson, Molly; Hodgson, Edward

2012-01-01

369

Water vapor toward starless cores: The Herschel view  

NASA Astrophysics Data System (ADS)

Aims: Previous studies by the satellites SWAS and Odin provided stringent upper limits on the gas phase water abundance of dark clouds (x(H2O) < 7 × 10-9). We investigate the chemistry of water vapor in starless cores beyond the previous upper limits using the highly improved angular resolution and sensitivity of Herschel and measure the abundance of water vapor during evolutionary stages just preceding star formation. Methods: High spectral resolution observations of the fundamental ortho water (o-H2O) transition (557 GHz) were carried out with the Heterodyne Instrument for the Far Infrared onboard Herschel toward two starless cores: Barnard 68 (hereafter B68), a Bok globule, and LDN 1544 (L1544), a prestellar core embedded in the Taurus molecular cloud complex. Detailed radiative transfer and chemical codes were used to analyze the data. Results: The RMS in the brightness temperature measured for the B68 and L1544 spectra is 2.0 and 2.2 mK, respectively, in a velocity bin of 0.59 km s-1. The continuum level is 3.5 ± 0.2 mK in B68 and 11.4 ± 0.4 mK in L1544. No significant feature is detected in B68 and the 3? upper limit is consistent with a column density of o-H2O N(o-H2O) < 2.5 × 1013 cm-2, or a fractional abundance x(o-H2O) < 1.3 × 10-9, more than an order of magnitude lower than the SWAS upper limit on this source. The L1544 spectrum shows an absorption feature at a 5? level from which we obtain the first value of the o-H2O column density ever measured in dark clouds: N(o-H2O) = (8 ± 4) × 1012 cm-2. The corresponding fractional abundance is x(o-H2O) ? 5 × 10-9 at radii >7000 AU and ?2 × 10-10 toward the center. The radiative transfer analysis shows that this is consistent with a x(o-H2O) profile peaking at ?10-8, 0.1 pc away from the core center, where both freeze-out and photodissociation are negligible. Conclusions: Herschel has provided the first measurement of water vapor in dark regions. Column densities of o-H2O are low, but prestellar cores such as L1544 (with their high central densities, strong continuum, and large envelopes) appear to be very promising tools to finally shed light on the solid/vapor balance of water in molecular clouds and oxygen chemistry in the earliest stages of star formation. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Caselli, P.; Keto, E.; Pagani, L.; Aikawa, Y.; Y?ld?z, U. A.; van der Tak, F. F. S.; Tafalla, M.; Bergin, E. A.; Nisini, B.; Codella, C.; van Dishoeck, E. F.; Bachiller, R.; Baudry, A.; Benedettini, M.; Benz, A. O.; Bjerkeli, P.; Blake, G. A.; Bontemps, S.; Braine, J.; Bruderer, S.; Cernicharo, J.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Doty, S. D.; Encrenaz, P.; Fich, M.; Fuente, A.; Gaier, T.; Giannini, T.; Goicoechea, J. R.; de Graauw, Th.; Helmich, F.; Herczeg, G. J.; Herpin, F.; Hogerheijde, M. R.; Jackson, B.; Jacq, T.; Javadi, H.; Johnstone, D.; Jørgensen, J. K.; Kester, D.; Kristensen, L. E.; Laauwen, W.; Larsson, B.; Lis, D.; Liseau, R.; Luinge, W.; Marseille, M.; McCoey, C.; Megej, A.; Melnick, G.; Neufeld, D.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Shipman, R.; Siegel, P.; van Kempen, T. A.; Visser, R.; Wampfler, S. F.; Wyrowski, F.

2010-10-01

370

Fundamental Experiments and Numerical Analyses on Heat Transfer Characteristics of a Vapor Chamber  

NASA Astrophysics Data System (ADS)

A vapor chamber is used as a novel heat spreader to cool high-performance MPUs (microprocessor units). The vapor chamber is placed between small heat sources and a large heat sink. This paper describes the effect of heat source size on the heat transfer characteristics of the vapor chamber. First, by the experiments, the effect of heat source size on the temperature distribution of the vapor chamber is investigated, and the validity of the mathematical model of the vapor chamber is confirmed. Secondly, by the numerical analyses, the effect of heat source size on the thermal resistances inside the vapor chamber is discussed. It is found that the heat source size greatly affects the thermal resistance of the evaporator section inside the vapor chamber. Although the thermal resistance is hardly affected by the heat generation rate and the heat flux of the heat source, it increases as the heat source becomes smaller.

Koito, Yasushi; Imura, Hideaki; Mochizuki, Masataka; Saito, Yuji; Torii, Shuichi

371

The Use of Water Vapor for Detecting Environments that Lead to Convectively Produced Heavy Precipitation and Flash Floods  

NASA Technical Reports Server (NTRS)

This Tech Report summarizes years of study and experiences on using GOES Water vapor (6.7 micron and precipitable water) and Special Sensor Microwave Imager (SSM/1) from the Defense Meteorological Satellite Program (DMSP) derived Precipitable Water (PNAI) for detecting environments favorable for convectively produced flash floods. An emphasis is on the moisture. upper air flow, and equivalent potential temperature (Theta(sub e)) patterns that lead to devastating flood events. The 15 minute 6.7 micron water vapor imagery is essential for tracking middle to upper tropospheric disturbances that produce upward vertical motion and initiate flash flood producing systems. Water vapor imagery at 6.7 micron is also used to detect surges of upper level moisture (called tropical water vapor plumes) that have been associated with extremely heavy rainfall. Since the water vapor readily depicts lifting mechanisms and upper level moisture, water vapor imagery is often an excellent source of data for recognizing patterns of heavy precipitation and flash floods. In order to analyze the depth of the moisture, the PW aspects of the troposphere must be measured. The collocation (or nearby location) of high values ofP\\V and instability are antecedent conditions prior to the flash flood or heavy rainfall events. Knowledge of PW magnitudes have been used as thresholds for impending flash flood events, PW trends are essential in flash flood prediction. Conceptual models and water vapor products are used to study some of the characteristics of convective systems that occurred over the United States of America (USA) during the summer of 1997 and the 1997-1998 El Nino. P\\V plumes were associated with most of the \\vest coast heavy precipitation events examined during the winter season of 1997 - 1998, In another study, conducted during the summer season of 1997. results showed that the collocation of water vapor (6.7 micron) and P\\N' plumes possessed higher correlations with predicted rainfall amounts than when PW plumes occurred by themselves (i.e.. without the presence of 6.7 micron water vapor plumes). Satellite Analysis Branch (SAB) meteorologists use the 6.7 micron water and P\\V products for their QPE's (interactive Flash Flood Analyzer (IFFA) and Auto-Estimator precipitation estimates), Outlooks, and heavy precipitation briefings with the Hydrometeorological Prediction Center/National Center for Environmental Prediction.

Scofield, Rod; Vicente, Gilberto; Hodges, Mike

2000-01-01

372

The Effects of Water Vapor and Hydrogen on the High-Temperature Oxidation of Alloys  

SciTech Connect

Essentially all alloys and coatings that are resistant to corrosion at high temperature require the formation of a protective (slowly-growing and adherent) oxide layer by a process known as selective oxidation. The fundamental understanding of this process has been developed over the years for exposure in pure oxygen or air. However, the atmospheres in most applications contain significant amounts of water vapor which can greatly modify the behavior of protective oxides. The development of oxy-fuel combustion systems in which fossil fuels are burned in a mixture of recirculated flue gas and oxygen, rather than in air, has caused renewed interest in the effects of water vapor and steam on alloy oxidation. The focus of this paper is on the ways the presence of water vapor can directly alter the selective oxidation process. The paper begins with a brief review of the fundamentals of selective oxidation followed by a description of recent experimental results regarding the effect of water vapor on the oxidation of a variety of chromia-forming alloys (Fe- and Ni-base) in the temperature range 600 to 700 °C. The atmospheres include air, air-H{sub 2}O, Ar-H{sub 2}O and Ar-H{sub 2}O-O{sub 2}. Then the behavior of alumina-forming alloys in H{sub 2}O-containing atmospheres is briefly described. As hydrogen is produced during oxidation of alloys in H{sub 2}O, it can be released back into the gas phase or injected into the metal (where it can diffuse through to the other side). Experiments in which hydrogen concentrations have been measured on both sides of thin specimens during oxidation by H{sub 2}O on only one side are described. Finally, it is attempted to catalogue the various experimental observations under a few general principles.

Mu, N.; Jung, K.; Yanar, N. M.; Pettit, F. S; Holcomb, G. R.; Howard, B. H.; Meier, G. H.

2013-06-01

373

Development and Validation of Water Vapor Tracers as Diagnostics for the Atmospheric Hydrologic Cycle  

NASA Technical Reports Server (NTRS)

Understanding of the local and remote sources of water vapor can be a valuable diagnostic in understanding the regional atmospheric hydrologic cycle. In the present study, we have implemented passive tracers as prognostic variables to follow water vapor evaporated in predetermined regions until the water tracer precipitates. The formulation of the sources and sinks of tracer water is generally proportional to the prognostic water vapor variable. Because all water has been accounted for in tracers, the water vapor variable provides the validation of the tracer water and the formulation of the sources and sinks. The tracers have been implemented in a GEOS General Circulation Model (GCM) simulation consisting of several summer periods to determine the source regions of precipitation for the United States and India. The recycling of water and interannual variability of the sources of water will be examined. Potential uses in GCM sensitivity studies, predictability studies and data assimilation will be discussed.

Bosilovich, Michael G.; Schubert, Siegfried D.; Einaudi, Franco (Technical Monitor)

2000-01-01

374

Oxidation of Ultra-High Temperature Ceramics in Water Vapor  

NASA Technical Reports Server (NTRS)

Ultra High Temperature Ceramics (UHTCs) including HfB2 + 20% SiC (HS), and ZrB2 + 20% SiC (ZC), and ZrB2 + 30% C + 14% SiC (ZCS) have been investigated for use as potential aeropropolsion engine materials. These materials were oxidized in water vapor (90%) using a cyclic vertical furnace at 1 atm. The total exposure time was 10 hours at temperature of 1200, 1300, and 1400 C. CVD SiC was also evaluate as a baseline for comparison. Weight change, X-ray diffraction analysis, surface and cross-sectional SEM and EDS were performed. These results are compared with tests conducted in a stagnant air furnace at temperatures of 1327 C for 100 minutes, and with high pressure burner rig (HPBR) results at 1100 and 1300 C at 6 atm for 50 h. Total recession measurements are also reported for the two tests environments.

Nguyen, QuynGiao N.; Robinson, Raymond C.; Opila, Elizabeth J.

2004-01-01

375

Global lower mesospheric water vapor revealed by LIMS observations  

NASA Astrophysics Data System (ADS)

The Limb Infrared Monitor of the Stratospheric water vapor channel data analysis has been extended from the 1. mb level (about 48 km) to the .3 mb level (about 60 km) through a radiance averaging procedure and better understanding of systematic errors. The data show H2O mixing ratio peaks near the .5 mb level varying from 4 to 7 ppmv with latitude and season. Above this level the mixing ratio drops off quickly with altitude, but, due to experimental uncertainties, at an uncertain rate. The stratospheric results are virtually the same as determined from the archived LIMS results with a tropical hygropause and enhanced H2O concentration in the lower levels at high winter latitudes.

Gordley, L. L.; Russell, J. M., III; Remsberg, E. E.

376

Global lower mesospheric water vapor revealed by LIMS observations  

NASA Technical Reports Server (NTRS)

The Limb Infrared Monitor of the Stratospheric water vapor channel data analysis has been extended from the 1. mb level (about 48 km) to the .3 mb level (about 60 km) through a radiance averaging procedure and better understanding of systematic errors. The data show H2O mixing ratio peaks near the .5 mb level varying from 4 to 7 ppmv with latitude and season. Above this level the mixing ratio drops off quickly with altitude, but, due to experimental uncertainties, at an uncertain rate. The stratospheric results are virtually the same as determined from the archived LIMS results with a tropical hygropause and enhanced H2O concentration in the lower levels at high winter latitudes.

Gordley, L. L.; Russell, J. M., III; Remsberg, E. E.

1985-01-01

377

Raman-shifted dye laser for water vapor DIAL measurements  

SciTech Connect

For improved DIAL measurements of water vapor in the upper troposphere or lower stratosphere, we have generated narrowband (--0.03-cm/sup -1/) laser radiation at 720- and 940-nm wavelengths by stimulated Raman scattering (SRS) using the narrow linewidth (--0.02-cm/sup -1/) output of a Nd:YAG-pumped dye laser. For a hydrogen pressure of 350 psi, the first Stokes conversion efficiencies to 940 nm were 20% and 35% when using a conventional and waveguide Raman cell, respectively. We measured the linewidth of the first Stokes line at high cell pressures and inferred collisional broadening coefficients that agree well with those previously measured in spontaneous Raman scattering.

Grossmann, B.E.; Singh, U.N.; Higdon, N.S.; Cotnoir, L.J.; Wilkerson, T.D.; Browell, E.V.

1987-05-01

378

Geographic Effects on Precipitation, Water Vapor and Temperature  

NSDL National Science Digital Library

There are many factors that affect an areaâs climate. By understanding these factors, someone could predict the average temperature, temperature range, and precipitation patterns of an area. They could also predict the type of vegetation likely to grow in an area based on these atmospheric conditions. In this activity, students will work in groups of three. Each group will be assigned one of six sets of cities. Each group will be responsible for comparing and contrasting the temperature, precipitation, and water vapor for the two cities in their set. At the end of the activity, students will present their findings to the rest of the class and determine whether or not the two locations have similar or different climatic conditions.

379

Formation and Survival of Water Vapor in the Terrestrial Planet-Forming Region  

NASA Astrophysics Data System (ADS)

Recent astronomical observations have revealed what may prove to be the ubiquity of water vapor during the early stages of planet formation. We present here a simple mechanism showing how water vapor forms in situ and is capable of shielding itself from molecule-destroying stellar radiation. The absorption of this radiation by water can control the thermodynamics of the terrestrial planet-forming zone. Similar to Earth's ozone layer, which shelters the chemistry of life, the water layer protects other water molecules and allows for a rich organic chemistry. The total abundance of water vapor in the natal habitable zone is equal to that of several thousand oceans.

Bethell, Thomas; Bergin, Edwin

2009-12-01

380

Terahertz absorption spectrum of water vapor at different humidity at room temperature  

NASA Astrophysics Data System (ADS)

We measured the absorption spectrum of water vapor in 0.2-2.4THz range at different humidity from 17% to 98% at room temperature using Er: doped fiber laser (IMRA America Inc.) based terahertz time-domain spectroscopy. The experiments were performed in a nitrogen-purged cage at atmosphere environment to obtain the reference and water absorption information. The seventeen absorption lines were observed due to water molecular rotations in the ground vibration state. The first three absorption lines at low frequencies increase with humidity, following the Beer-Lambert Law, while some of high frequency lines were found to decrease with humidity. These effects will be discussed. The observed line broadening is due to collisions occurring among water and nitrogen molecules.

Xin, Xuying; Altan, Hakan; Matten, David; Saint, Angelamaria; Alfano, Robert

2006-03-01

381

Interferometric millimeter observations of water vapor on Mars  

NASA Astrophysics Data System (ADS)

We present interferometric mapping of the 225.9-GHz HDO and 203.4-GHz H2 18O lines on Mars obtained with the IRAM Plateau de Bure facility (PdBI). The observations were performed during martian year 28 (MY28), at Ls = 320.3° for the HDO line, and at Ls = 324.3° for the H2 18O line. The HDO line is detected at the eastern (morning) and western (evening) limbs of the northern hemisphere, corresponding to a water column density in the range 3-6 pr.-?m(Fig. 1). The H2 18O line is not detected, which is compatible with the column densities derived from the HDO line (Fig. 2). Quasi-simultaneous far infrared measurements obtained by the Planetary Fourier Spectrometer (PFS) onboard the Mars Express spacecraft confirm our PdBI results, yielding a 5±1 pr.-?m meridionally constant water column abundance (Fig 3). Such a low water abundance during the southern mid-autumn of MY28 does not correspond to the standard martian climatology as observed during the previous years. It was however already retrieved from near-infrared observations performed by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter spacecraft [Smith, M. D., Wolff, M. J., Clancy, R. T., Murchie, S. L. 2009. CRISM observations of water vapor and carbon monoxide. J. Geophys. Res. 114, doi:10.1029/2008JE003288]. Our observations thus confirm that the planet-encircling dust storm that occured during MY28 significantly affected the martian water cycle. Our observations also demonstrate the usefulness of interferometric submillimeter observations to survey the martian water cycle from groundbased facilities.

Fouchet, T.; Moreno, R.; Lellouch, E.; Montmessin, F.; Giuranna, M.; Formisano, V.

2011-10-01

382

MM-Wave Radiometric Measurements of Low Amounts of Precipitable Water Vapor  

NASA Technical Reports Server (NTRS)

An experiment was conducted during March, 1999 to study ways in which to improve techniques for measuring low amounts of total-column precipitable water vapor (PWV). The experiment was conducted at the DOE's ARM program's North Slope of Alaska/Adjacent Arctic Ocean Cloud and Radiation Testbed site (DoE ARM NSA/AAO CaRT) located just outside Barrow, Alaska. NASA and NOAA deployed a suite of radiometers covering 25 channels in the frequency range of 20 GHz up to 340 GHz including 8 channels around the 183 GHz water vapor absorption line. In addition to the usual CaRT site instrumentation the NOAA Depolarization and Backscatter Unattended Lidar (DABUL), the SUNY Rotating Shadowband Spectroradiometer (RSS) and other surface based meteorological instrumentation were deployed during the intensive observation period. Vaisala RS80 radiosondes were launched daily as well as nearby National Weather Service VIZ sondes. Atmospheric conditions ranged from clear calm skies to blowing snow and heavy multi-layer cloud coverage. Measurements made by the radiosondes indicate the PWV varied from approx. 1 to approx. 5 mm during the experiment. The near-surface temperature varied between about -40 C to - 15 C. In this presentation, an overview of the experiment with examples of data collected will be presented. Application of the data for assessing the potential and limitations of millimeter-wave radiometry for retrieving very low amounts of PWV will be discussed.

Racette, P.; Westwater, Ed; Han, Yong; Manning, Will; Jones, David; Gasiewski, Al

2000-01-01

383

Analysis of satellite-derived ozone and water vapor measurements  

NASA Technical Reports Server (NTRS)

Research under this grant has involved analyses of satellite-derived measurements of water vapor and total ozone. Upper tropospheric water vapor data from the Nimbus 7 temperature-humidity infrared radiometer (THIR) 6.7 micron channel were analyzed by Fourier transformation to provide wavenumber spectra for a case of an upper level system over Europe. The power law spectrum for horizontal scales from 60 to several hundred km suggests that when convective cloud energy sources are not present, the enstrophy-cascading process (with variance proportional to the minus three power of wavenumber) may hold to much smaller scales than previously thought. Several investigations of the middle atmosphere (stratosphere and mesosphere) were also conducted. Slow atmospheric oscillations with periods of 1-2 months were investigated in total ozone measurements and in ionospheric data. Using one-point correlation maps and total ozone mapping spectrometer (TOMS) data, strong statistical evidence was found for the planetary-scale oscillations at these periods. A dipole-like pattern in the tropical equatorial Indian ocean-western Pacific region was documented, along with wavetrain-like patterns emanating into the extratropics. While attempting to follow the oscillations upward above stratosphere, oscillations were studied in ionospheric data (D-region radio wave absorption, in the upper mesosphere, around 80-90 km altitude). Cross-spectral analyses with solar flux data revealed that much of the observed 1-2 month variance in the ionospheric D-region was well correlated to solar variations. Further research has involved investigations of the photochemical lifetime of greenhouse gases methane and nitrous oxide. Using Nimbus 7 satellite data, a new analysis technique was employed to determine the lifetime of these gases in situ in the upper stratosphere. The lifetimes are found to be in good agreement with theoretical estimates.

Stanford, John L.

1992-01-01

384

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  

Microsoft Academic Search

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

Bryan Mills Karpowicz

2010-01-01

385

Water, Vapor, and Salt Dynamics in a Hot Repository  

SciTech Connect

The purpose of this paper is to report the results of a new model study examining the high temperature nuclear waste disposal concept at Yucca Mountain using MULTIFLUX, an integrated in-drift- and mountain-scale thermal-hydrologic model. The results show that a large amount of vapor flow into the drift is expected during the period of above-boiling temperatures. This phenomenon makes the emplacement drift a water/moisture attractor during the above-boiling temperature operation. The evaporation of the percolation water into the drift gives rise to salt accumulation in the rock wall, especially in the crown of the drift for about 1500 years in the example. The deposited salts over the drift footprint, almost entirely present in the fractures, may enter the drift either by rock fall or by water drippage. During the high temperature operation mode, the barometric pressure variation creates fluctuating relative humidity in the emplacement drift with a time period of approximately 10 days. Potentially wet and dry conditions and condensation on salt-laden drift wall sections may adversely affect the storage environment. Salt accumulations during the above-boiling temperature operation must be sufficiently addressed to fully understand the waste package environment during the thermal period. Until the questions are resolved, a below-boiling repository design is favored where the Alloy-22 will be less susceptible to localized corrosion. (authors)

Bahrami, Davood; Danko, George [Department of Mining Engineering, University of Nevada, Reno, 1664 N. Virginia St., Reno, NV, 89557 (United States); Walton, John [Department of Civil Engineering, University of Texas at El Paso, 500 W. University, El Paso, TX, 79968 (United States)

2007-07-01

386

Water Vapor Variations over Mauna Loa and Table Mountain since 2010  

NASA Astrophysics Data System (ADS)

The Vapor Millimeter-wave Spectrometer (WVMS) instrument deployed at Network for the Detection of Atmospheric Composition Change (NDACC) sites at Table Mountain, California (34.4N, 242.3E) and at Mauna Loa, Hawaii (19.5N, 204.4E) have, since 2010, been able to make measurements down to ~26km. With this extended retrieval capability these instruments can now make measurements from ~26-80km. There is an increase from 2010 to 2012 which appears to be caused primarily by dynamical variations, although an increase in water vapor entering the stratosphere probably also plays a role at the lower altitudes. Water vapor mixing ratios at both of these NDACC sites are now higher than they have been for about a decade from the lower stratosphere through the mid-mesosphere. In addition to the WVMS measurements, we will present coincident satellite measurements from the Aura Microwave Limb Sounder (MLS), the Atmospheric Chemistry Experiment (ACE), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We will also compare the lowest altitude WVMS measurements with frostpoint hygrometer measurements from Boulder, Colorado (40N, 255E), and Hilo, Hawaii (19.7N, 205E). In order to understand the interannual dynamically-driven changes in water vapor, we will investigate interannual variations in mixing using equivalent length and tracer equivalent latitude from 2010-2012. Since dynamical variations affect H2O in the stratosphere primarily by changing the amount of CH4 oxidation that has occurred in a particular region, we will also examine CH4 variations from the GMI model.

Nedoluha, G. E.; Gomez, R. M.; Allen, D. R.; Boone, C.; Lambert, A.; Stiller, G. P.; Hurst, D. F.

2012-12-01

387

Heat and Mass Diffusions in the Absorption of Water Vapor by Aqueous Solution of Lithium Bromide  

NASA Astrophysics Data System (ADS)

The recent development of absorption-type heat pump is highly essential from the viewpoint of extracting the effective energy from waste heat or solar energy. To increase the efficiency of energy conversion, it is important to improve the performance of absorbers. The objective of this paper is to obtain an increased understanding of the fine mechanisms of vapor absorption. A system combining holographic interferometry wity thermometry is adopted to observe the progress of one-dimensional water vapor absorption by aqueous solution of lithium bromide (LiBr) and also to measure the unsteady temperature and concentration distributions in the absorption process. The experiments are carried out under the condition that the solution surface is exposed to the saturated water vapor at reduced pressure, and the effects of LiBr mass concentration on absorption mechanism are examined in the concentration range 20-60 mass%. The interference fringes are analyzed to distinguish between the layers of heat conduction and mass diffusion. The temperature and concentration distributions thus determined experimentally are compared with numerical solutions obtained by the equations for unsteady heat conduction and mass diffusion taking into consideration the effect of heat by dilution, to give reasonable values of mass diffusivity hitherto remaining unknown. Especially in the range of 40-60 mass%, the mass diffusivity decreases extremely with the increase of mass concentration of LiBr and it falls down to 0.7-0.8×10-9 m2/s in case of 60 mass% solution.

Kashiwagi, Takao; Kurosaki, Yasuo; Nikai, Isao

388

Description of data on the Nimbus 7 LIMS map archive tape: Water vapor and nitrogen dioxide  

NASA Technical Reports Server (NTRS)

Described is the process by which the analysis of the Limb Infrared Monitor of the Stratosphere (LIMS) experiment data were used to produce estimates of synoptic maps of water vapor and nitrogen dioxide. In addition to a detailed description of the analysis procedure, also discussed are several interesting features in the data which are used to demonstrate how the analysis procedure produced the final maps and how one can estimate the uncertainties in the maps. In addition, features in the analysis are noted that would influence how one might use, or interpret, the results. These include subjects such as smoothing and the interpretation of wave components.

Haggard, Kenneth V.; Marshall, B. T.; Kurzeja, Robert J.; Remsberg, Ellis E.; Russell, James M., III

1988-01-01

389

Application of improved technology to a preprototype vapor compression distillation /VCD/ water recovery subsystem  

NASA Technical Reports Server (NTRS)

Vapor compression distillation (VCD) is considered the most efficient water recovery process for spacecraft application. This paper reports on a preprototype VCD which has undergone the most extensive operational and component development testing of any VCD subsystem to date. The component development effort was primarily aimed at eliminating corrosion and the need for lubrication, upgrading electronics, and substituting nonmetallics in key rotating components. The VCD evolution is documented by test results on specific design and/or materials changes. Innovations worthy of further investigation and additional testing are summarized for future VCD subsystem development reference. Conclusions on experience gained are presented.

Johnson, K. L.; Reysa, R. P.; Fricks, D. H.

1981-01-01

390

A Two-Line Absorption Instrument for Scramjet Temperature and Water Vapor Concentration Measurement in HYPULSE  

NASA Technical Reports Server (NTRS)

A three beam water vapor sensor system has been modified to provide for near simultaneous temperature measurement. The system employs a tunable diode laser to scan spectral line of water vapor. The application to measurements in a scramjet combustor environment of a shock tunnel facility is discussed. This report presents and discusses die initial calibration of the measurement system.

Tsai, C. Y.

1998-01-01

391

GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System  

Microsoft Academic Search

We present a new approach to remote sensing of water vapor based on the global positioning system (GPS). Geodesists and geophysicists have devised methods for estimating the extent to which signals propagating from GPS satellites to ground-based GPS receivers are delayed by atmospheric water vapor. This delay is parameterized in terms of a time-varying zenith wet delay (ZWD) which is

Michael Bevis; Steven Businger; Thomas A. Herring; Christian Rocken; Richard A. Anthes; Randolph H. Ware

1992-01-01

392

Geodesy by radio interferometry: Water vapor radiometry for estimation of the wet delay  

Microsoft Academic Search

An important source of error in very-long-baseline interferometry (VLBI) estimates of baseline length is unmodeled variations of the refractivity of the neutral atmosphere along the propagation path of the radio signals. The authors present and discuss the method of using data from a water vapor readiometer (WVR) to correct for the propagation delay caused by atmospheric water vapor, the major

G. Elgered; J. L. Davis; T. A. Herring; I. I. Shapiro

1991-01-01

393

Water Vapor Feedback in the Tropical Upper Troposphere: Model Results and Observations  

Microsoft Academic Search

The sensitivity of water vapor in the tropical upper troposphere to changes in surface temperature is examined using a single-column, radiative convective model that includes couplings between the moistening effects of convective detrainment, the drying effects from clear-air subsidence, and radiative heating and cooling from water vapor. Equilibrium states of this model show that as the surface warms, changes in

Ken Minschwaner; Andrew E. Dessler

2004-01-01

394

Pointed water vapor radiometer corrections for accurate global positioning system surveying  

Microsoft Academic Search

Delay of the Global Positioning System (GPS) signal due to atmospheric water vapor is a major source of error in GPS surveying. Improved vertical accuracy is important for sea level and polar isostasy measurements, geodesy, normal fault motion, subsidence, earthquake studies, air and ground-based gravimetry, ice dynamics, and volcanology. We conducted a GPS survey using water vapor radiometers (WVRs) pointed

Randolph Ware; Christian Rocken; Fredrick Solheim; Teresa Van Hove; Chris Alber; James Johnson

1993-01-01

395

High Temperature Corrosion of Silicon Carbide and Silicon Nitride in Water Vapor  

NASA Technical Reports Server (NTRS)

Silicon carbide (SiC) and silicon nitride (Si3N4) are proposed for applications in high temperature combustion environments containing water vapor. Both SiC and Si3N4 react with water vapor to form a silica (SiO2) scale. It is therefore important to understand the durability of SiC, Si3N4 and SiO2 in water vapor. Thermogravimetric analyses, furnace exposures and burner rig results were obtained for these materials in water vapor at temperatures between 1100 and 1450 C and water vapor partial pressures ranging from 0.1 to 3.1 atm. First, the oxidation of SiC and Si3N4 in water vapor is considered. The parabolic kinetic rate law, rate dependence on water vapor partial pressure, and oxidation mechanism are discussed. Second, the volatilization of silica to form Si(OH)4(g) is examined. Mass spectrometric results, the linear kinetic rate law and a volatilization model based on diffusion through a gas boundary layer are discussed. Finally, the combined oxidation and volatilization reactions, which occur when SiC or Si3N4 are exposed in a water vapor-containing environment, are presented. Both experimental evidence and a model for the paralinear kinetic rate law are shown for these simultaneous oxidation and volatilization reactions.

Opila, E. J.; Robinson, Raymond C.; Cuy, Michael D.; Gray, Hugh R. (Technical Monitor)

2002-01-01

396

Microwave Radiometer Networks for Measurement of the Spatio-Temporal Variability of Water Vapor  

Microsoft Academic Search

Tropospheric water vapor plays a key role in the prediction of convective storm initiation, precipitation and extreme weather events. Conventionally, water vapor profiles are derived from dewpoint and temperature measurements using instrumented weather balloons, including radiosondes. These balloons take approximately one hour to measure from surface to tropopause, and transmitter-sensor packages cannot be reused. Such in-situ measurements provide profiles with

S. C. Reising; F. Iturbide-Sanchez; S. Padmanabhan

2006-01-01

397

Pointed water vapor radiometer corrections for accurate Global Positioning System surveying  

Microsoft Academic Search

Delay of the Global Positioning System (GPS) signal due to atmospheric water vapor is a major source of error in GPS surveying. Improved vertical accuracy is important for sea level and polar isostasy measurements, geodesy, normal fault motion, subsidence, earthquake studies, air and ground-based gravimetry, ice dynamics, and volcanology. We conducted a GPS survey using water vapor radiometers (WVRs) pointed

Randolph Ware; Christian Rocken; Fredrick Solheim; Teresa Van Hove; Chris Alber; James Johnson

1993-01-01

398

A differential technique to retrieve column water vapor using sun radiometry  

Microsoft Academic Search

Techniques for retrieving column water vapor from Sun radiometer measurements involving the 940-nm water vapor absorption band have been around for the better part of a century. Arguably, the best method to use for this retrieval is the modified Langley technique. However, to apply this method one must obtain the instrument response at the top of the atmosphere using modified

Joseph J. Michalsky; Qilong Min; Piotr W. Kiedron; Donald W. Slater; James C. Barnard

2001-01-01

399

Alexandrite laser characterization and airborne lidar developments for water vapor DIAL measurements  

NASA Technical Reports Server (NTRS)

The spectral characteristics of an Alexandrite laser used for making water vapor DIAL measurements have been evaluated. The optical servo-system used to lock the laser wavelength on a water vapor absorption line is described. A brief description of the DIAL system is given and the data obtained with this lidar during flight tests in March 1990 are also presented.

Ponsardin, P.; Higdon, N. S.; Grossmann, B. E.; Browell, E. V.

1991-01-01

400

Mixed water vapor\\/gas transport through the rubbery polymer PEBAX ® 1074  

Microsoft Academic Search

This work investigates the transport behavior of a hydrophilic, highly permeable type of poly ethylene oxide (PEO)-based block copolymer (PEBAX® 1074) as membrane material for the removal of water vapor from light gases. Water vapor sorption isotherms in PEBAX® 1074 represent Flory–Huggins type of sorption and the highly hydrophilic nature of the block copolymer results in high amounts of absorbed

Jens Potreck; Kitty Nijmeijer; Thomas Kosinski; Matthias Wessling

2009-01-01

401

Atmospheric water vapor over Antarctica derived from Special Sensor Microwave\\/Temperature 2 data  

Microsoft Academic Search

In polar regions, satellite microwave radiometry has not been successful in measuring the total water vapor (TWV) in the atmosphere. The difficulties faced in these regions arise from the very low water vapor burden of the atmosphere and the large and highly variable emissivities of ice surfaces in the microwave frequency range. By exploiting the advantages of the Special Sensor

Jungang Miao; Klaus Kunzi; Georg Heygster; Tom A. Lachlan-Cope; John Turner

2001-01-01

402

Evaluation of the Water Vapor Transport over the Yellow River Basin in CMIP5 Models  

NASA Astrophysics Data System (ADS)

Temperature, precipitation and water vapor transport in China, particularly in the Yellow River Basin simulated by the 16 models participating in phase 5 of the Coupled Model Inter-comparison Project (CMIP5) were evaluated for the period 1979-2005. Results suggest that most CMIP5 models are able to capture the climatological distribution patterns and inter-annual variations of surface air temperature, but with cold bias. Most models reproduce the spatial distribution pattern of warming trends identical with observations. Models tend to overestimate precipitation with relative biases ranging from 4.59 % to 61.46 %. Compared with observations, most models simulate more precipitation over the east of Tibetan Plateau and less in southeastern coastal regions. The spatial distribution of precipitation trends displayed in the observations cannot be well simulated by most models. The underestimation of temperature and the overestimation of precipitation simulated by some models over the east of Tibetan Plateau may be related to the anomalously strong western Pacific subtropical high and sufficient water vapor transport from Indian Ocean and western Pacific Ocean. In terms of the Yellow River Basin, modeled water vapor mainly flows in from eastern boundary and out from the western boundary. Water vapor also flows in through the southern boundary, but with smaller intensity. Owing to the overestimation of water vapor convergence, some models tend to exaggerate the climatological precipitation. Additionally, we found that the summer water vapor budget and precipitation keep pace with each other, which is well reflected by the FIO-ESM model. Models can also reproduce this relation in the lower reaches, with the total water vapor budget correlated strongly with water vapor transport from eastern, western and southern boundaries, indicating that water vapor budget and even the precipitation are strongly influenced by the water vapor transport from Indian Ocean and western Pacific Ocean. This situation is almost similar to the middle reaches, though the total water vapor budget is only related to water vapor transport from eastern and western boundaries, which mainly come from Indian Ocean. Nonetheless, in the upper reaches of the Yellow River Basin most models substantially underestimate the great contribution of water vapor transport from eastern and western boundaries, but overestimate the one from southern boundary, indicating that most models strongly overestimate the water vapor transport from the western Pacific Ocean which needs further improvement.

Bao, Jiawei; Feng, Jinming

2014-05-01

403

Radiative cooling by stratospheric water vapor: Big differences in GCM results  

NASA Astrophysics Data System (ADS)

The stratosphere has been cooling by about 2K/decade at 30-60 km over the past several decades and by lesser amounts toward the tropopause. Climate model calculations suggest that stratospheric water vapor is an important contributor to the observed stratospheric cooling, but there are large differences among recent GCM simulations for prescribed changes in stratospheric water vapor, which point to problems with the current GCM treatment of the absorption and emission by stratospheric water vapor. We show that the correlated k-distribution treatment with sufficient resolution is capable of simulating accurately cooling by stratospheric water vapor. We obtain equilibrium cooling of about 0.3K that extends from 20 km to the top of the atmosphere, and adjusted radiative forcing of 0.12 Wm-2, for a stratospheric water vapor increase of 0.7 ppmv which has been estimated for the period 1979-1997.

Oinas, V.; Lacis, A. A.; Rind, D.; Shindell, D. T.; Hansen, J. E.

404

Spatial pattern of terrestrial carbon dioxide and water vapor coupling  

NASA Astrophysics Data System (ADS)

The eddy covariance system installed at flux towers is capable to measure simultaneously ecosystem-atmosphere exchanges of carbon dioxide (CO2) and water vapor (H2O). Therefore, such data has been utilized to study an important plant physiological characteristic, the amount of water being lost per unit carbon gain (water use efficiency, WUE) at ecosystem level. By using global fields of leaf area index and land cover based on data from the SPOT Vegetation and TERRA MODIS sensors in conjunction with soil maps we extrapolated flux tower information about inherent WUE from FLUXNET stations to the global land surface. The additional usage of climate fields led to global WUE maps then. Highest uncertainties occur in tropical forests with a coefficient of variability of 50 %. We compare these spatial details of median WUE and its uncertainty with estimates of four prominent land-surface schemes of climate models (CLM, JSBACH, ORCHIDEE, LPJ) which all model the combined flow of CO2 and H2O through the stomata of plants in different ways. Such model evaluation is important for a deeper understanding of the model’s validity w. r. t. the carbon-water coupling. The data-driven WUE map shows a strong latitudinal pattern with peaks in the tropics and the boreal forest. The models mostly agree with this pattern, although WUE values are twice as high in the temperate and semi-arid regions, 25 % higher in the boreal zone, and two times higher in the tundra. Two of the models underestimate WUE in the tropics by 50 % when compared to the other two models and to the data-driven estimate. Disagreement between models and data does not depend on model structure which suggests that their parameterization does not adequately capture mean growing season WUE patterns - a result with implications for future climate simulations.

Beer, C.; Reichstein, M.; Ciais, P.; Davin, E. L.; Oliveira, P. J.; Piao, S.; Raddatz, T.; Tomelleri, E.; Viovy, N.

2009-12-01

405

Spatial pattern of terrestrial carbon dioxide and water vapor coupling  

NASA Astrophysics Data System (ADS)

The eddy covariance system installed at flux towers is capable to measuring simultaneously ecosystem-atmosphere exchanges of carbon dioxide (CO2) and water vapor (H2O). Therefore, such data has been utilized to study an important plant physiological characteristic, the amount of water being lost per unit carbon gain (water use efficiency, WUE) at ecosystem level. By using global fields of leaf area index and land cover based on data from the SPOT Vegetation and TERRA MODIS sensors in conjunction with soil maps we extrapolated flux tower information about inherent WUE from FLUXNET stations to the global land surface. The additional usage of climate fields led to global WUE maps then. Highest uncertainties occur in tropical forests with a coefficient of variability of 50 %. We compare these spatial details of median WUE and its uncertainty with estimates of four prominent land-surface schemes of climate models (CLM, JSBACH, ORCHIDEE, LPJ) which all model the combined flow of CO2 and H2O through the stomata of plants in different ways. Such model evaluation is important for a deeper understanding of the model's validity w. r. t. the carbon-water coupling. The data-driven WUE map shows a strong latitudinal pattern with peaks in the tropics and the boreal forest. The models mostly agree with this pattern, although WUE values are twice as high in the temperate and semi-arid regions, 25