Sample records for water vapor experiment

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

    ERIC Educational Resources Information Center

    Levinson, Gerald S.

    1982-01-01

    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)

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

    NASA Technical Reports Server (NTRS)

    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

    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.

  3. Tropospheric water vapor and aerosol measurements obtained during LASE validation experiment

    SciTech Connect

    Browell, E.V.; Ismail, S.; Hall, W.M.; Moore, A.S. [and others

    1996-10-01

    The Lidar Atmospheric Sensing Experiment (LASE) is a Differential Absorption Lidar (DIAL) system flown on the NASA ER-2 aircraft to remotely measure distributions of tropospheric water vapor, aerosols, and clouds. LASE was developed at the NASA Langley Research Center (LaRC) to demonstrate autonomous operation of a DIAL system from a high-altitude aircraft as an important step towards developing a spaceborne DIAL system. LASE uses a double pulsed Ti:sapphire laser operating in the 815-nm absorption band of water vapor to generate the on- and off-line DIAL laser pulses. The system has two avalanche photodiode detectors and three signal digitizers to preserve the lidar backscatter signals over a large dynamic range. In September 1995, LASE completed a comprehensive validation program at the NASA Wallops Flight Facility. The system was flown on the ER-2 during ten flights for a total of 60 hours. LASE measurements of tropospheric water vapor were compared with other remote and in situ measurements of water vapor from the ground and from aircraft which underflew the ER-2. Besides making intercomparisons with a number of water vapor sensors, this experiment incorporated a number of case studies related to atmospheric events including flights over and around Hurricane Luis over the Atlantic ocean, sea breeze development along the east coast of Virginia, and stratosphere-troposphere exchange. This paper presents data taken during this field experiment that demonstrate the accuracy of LASE for tropospheric water vapor measurements. The paper also discusses results from several of the atmospheric case studies conducted during this experiment and the potential future uses of LASE.

  4. Algorithms and sensitivity analyses for stratospheric aerosol and gas experiment II water vapor retrieval

    SciTech Connect

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

    1993-03-20

    This paper provides a detailed description of the current operational inversion algorithm for the retrieval of water vapor vertical profiles from the Stratospheric Aerosol and Gas Experiment II (SAGE II) occultation data at the 0.94-[mu]m wavelength channel. This algorithm is different from the algorithm used for the retrieval of the other species such as aerosol, ozone, and nitrogen dioxide because of the nonlinear relationship between the concentration versus the broad band absorption characteristics of water vapor. Included in the discussion of the retrieval algorithm are problems related to the accuracy of the computational scheme, accuracy of the removal of other interfering species, and the expected uncertainty of the retrieved profile. A comparative analysis on the computational schemes used for the calculation of the water vapor transmission at the 0.94-[mu]m wavelength region is presented. Analyses are also presented on the sensitivity of the retrievals to interferences from the other species which contribute to the total signature as observed at the 0.94-[mu]m wavelength channel on SAGE II instrument. Error analyses of the SAGE II water vapor retrieval is shown, indicating that good quality water vapor data are being produced by the SAGE II measurements. 27 refs., 10 figs., 1 tab.

  5. 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)

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

    1993-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

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

    Microsoft Academic Search

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

    1991-01-01

    The internal consistency of the baseline length measurements derived from analysis of several independent very long baseline interferometry (VLBI) experiments is an estimate of the measurement precision. In this paper we investigate 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

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

  11. LASE validation experiment: preliminary processing of relative humidity from LASE derived water vapor in the middle to upper troposphere

    NASA Technical Reports Server (NTRS)

    Brackett, Vincent G.; Ismail, Syed; Browell, Edward V.; Kooi, Susan A.; Clayton, Marian B.; Ferrare, Richard A.; Minnis, Patrick; Getzewich, Brian J.; Staszel, Jennifer

    1998-01-01

    Lidar Atmospheric Sensing Experiment (LASE) is the first fully engineered, autonomous airborne DIAL (Differentials Absorption Lidar) system to measure water vapor, aerosols, and clouds throughout the troposphere. This system uses a double-pulsed Ti:sapphire laser, which is pumped by a frequency-doubled flashlamp-pumped Nd: YAG laser, to transmit light in the 815 mn absorption band of water vapor. LASE operates by locking to a strong water vapor line and electronically tuning to any spectral position on the absorption line to choose the suitable absorption cross-section for optimum measurements over a range of concentrations in the atmosphere. During the LASE Validation Experiment, which was conducted over Wallops Island during September, 1995, LASE operated on either the strong water line for measurements in middle to upper troposphere, or on the weak water line for measurements made in the middle to lower troposphere including the boundary layer. Comparisons with water vapor measurements made by airborne dew point and frost point hygrometers, NASA/GSFC (Goddard Space Flight Center) Raman Lidar, and radiosondes showed the LASE water vapor mixing ratio measurements to have an accuracy of better than 6% or 0.01 g/kg, whichever is larger, throughout the troposphere. In addition to measuring water vapor mixing ratio profiles, LASE simultaneously measures aerosol backscattering profiles at the off-line wavelength near 815 nm from which atmospheric scattering ratio (ASR) profiles are calculated. ASR is defined as the ratio of total (aerosol + molecular) atmospheric scattering to molecular scattering. Assuming a region with very low aerosol loading can be identified, such as that typically found just below the tropopause, then the ASR can be determined. The ASR profiles are calculated by normalizing the scattering in the region containing enhanced aerosols to the expected scattering by the "clean" atmosphere at that altitude. Images of the total ASR clearly depict cloud regions, including multiple cloud layers, thin upper level cirrus, etc., throughout the troposphere. New data products that are being derived from the LASE aerosol and water measurements include: 1) aerosol extinction coefficient, 2) aerosol optical thickness, 3) precipitable water vapor, and 4) relative humidity (RH). These products can be compared with airborne in-situ, and ground and satellite remote sensing measurements,. This paper presents a preliminary examination of RH profiles in the middle to upper troposphere that are generated from LASE measured water vapor mixing ratio profiles coupled with rawinsonde profiles of temperature and pressure.

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

    Microsoft Academic Search

    F. Peters; B. Paikert

    1989-01-01

    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

  13. Experiments on Condensation of Water Vapor by Homogeneous Nucleation in Nozzles

    Microsoft Academic Search

    Peter P. Wegener; Andrew A. Pouring

    1964-01-01

    Condensation of water vapor in a highly supersaturated state was studied with steady flow of moist air in supersonic nozzles of different temperature gradients. With measured centerline static pressures, known initial conditions, and known nozzle geometry, the equations of motion could be solved. From these results heat addition to the flow owing to condensation could be determined. By estimating latent

  14. 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)

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

    1993-01-01

    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.

  15. Enceladus' water vapor plume.

    PubMed

    Hansen, Candice J; Esposito, L; Stewart, A I F; Colwell, J; Hendrix, A; Pryor, W; Shemansky, D; West, R

    2006-03-10

    The Cassini spacecraft flew close to Saturn's small moon Enceladus three times in 2005. Cassini's UltraViolet Imaging Spectrograph observed stellar occultations on two flybys and confirmed the existence, composition, and regionally confined nature of a water vapor plume in the south polar region of Enceladus. This plume provides an adequate amount of water to resupply losses from Saturn's E ring and to be the dominant source of the neutral OH and atomic oxygen that fill the Saturnian system. PMID:16527971

  16. Hydrogen Cars and Water Vapor

    E-print Network

    Colorado at Boulder, University of

    of complexities in the water vapor life cycle. How- ever, our pre- liminary calcula- tions indicate early in its development cycle. We are skeptical, however, that water vapor produced by combustion canHydrogen Cars and Water Vapor D.W.KEITHANDA.E.FARRELL'S POLICY FORUM "Rethinking hydrogen cars" (18

  17. 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.

  18. Observations of TTL water vapor and cirrus properties from the NASA Global Hawk during the Airborne Tropical TRopopause EXperiment

    NASA Astrophysics Data System (ADS)

    Thornberry, Troy; Rollins, Andrew; Gao, Ru-Shan; Woods, Sarah; Lawson, Paul; Bui, Thaopaul; Pfister, Leonhard; Fahey, David

    2015-04-01

    Despite its very low mixing ratios relative to the troposphere, water vapor in the lower stratosphere (LS) plays a significant role in Earth's radiative balance and climate system and is an important constituent in stratospheric chemistry. The low H2O content of air entering the LS is established to first order by dehydration processes controlled by the cold temperatures of the tropical tropopause layer (TTL), especially over the western Pacific. Cirrus clouds occur with high frequency and large spatial extent in the TTL, and those occurring near the thermal tropopause facilitate the final dehydration of stratosphere-bound air parcels. Uncertainties in aspects of the nucleation and growth of cirrus cloud particles and the sparseness of in situ water vapor and cirrus cloud observations with sufficient spatial resolution limit our ability to fully describe the final stages of the dehydration process before air enters the LS in the tropics. The NASA Airborne Tropical TRopopause EXperiment (ATTREX) measurement campaign has yielded more than 140 hours of sampling from the Global Hawk UAS in the Pacific TTL during deployments in winter 2013 and 2014, including more than 30 hours sampling TTL cirrus. Cirrus clouds were encountered throughout the TTL, up to the tropopause (17-18 km), with ice water contents (IWC) down to the detection limit of 3 ?g m-3 and water vapor mixing ratios as low as 1.5 ppm. Most TTL cirrus sampled had particle number concentrations of less than 100 L-1, but some had concentrations ranging up to more than 1000 L-1. The mean value for relative humidity with respect to ice within cirrus was near 100%, but encompassed a range from < 50% to higher than 150%. The high spatial and temporal resolution in situ measurements of water vapor and cirrus cloud properties made during ATTREX provide an outstanding dataset by which to characterize the Pacific TTL environment and evaluate our current understanding of the dynamical and microphysical processes that result in the dehydration of stratosphere-bound air in this region. Here we present an analysis of the ATTREX water vapor, relative humidity and cirrus cloud ice crystal measurements and IWC data to investigate cirrus cloud formation in the TTL and the resulting potential for dehydration.

  19. 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

    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

    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.

  20. The atmospheric water vapor line

    Microsoft Academic Search

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

    2008-01-01

    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

  1. Advanced Raman water vapor lidar

    NASA Technical Reports Server (NTRS)

    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

    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.

  2. TROPOSPHERIC WATER VAPOR, CONVECTION, AND CLIMATE

    E-print Network

    Sherwood, Steven

    Click Here for Full Article TROPOSPHERIC WATER VAPOR, CONVECTION, AND CLIMATE S. C. Sherwood,1 R with water vapor and changes associated with water vapor in warmer climates. Progress includes new observing the anticipated water vapor feedback on climate, though key uncertainties remain connected to atmospheric dynamics

  3. Adsorption of water vapor on reservoir rocks

    SciTech Connect

    Not Available

    1993-07-01

    Progress is reported on: adsorption of water vapor on reservoir rocks; theoretical investigation of adsorption; estimation of adsorption parameters from transient experiments; transient adsorption experiment -- salinity and noncondensible gas effects; the physics of injection of water into, transport and storage of fluids within, and production of vapor from geothermal reservoirs; injection optimization at the Geysers Geothermal Field; a model to test multiwell data interpretation for heterogeneous reservoirs; earth tide effects on downhole pressure measurements; and a finite-difference model for free surface gravity drainage well test analysis.

  4. Water vapor diffusion membranes, 2

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

  5. Electrical Breakdown in Water Vapor

    SciTech Connect

    Skoro, N.; Maric, D.; Malovic, G.; Petrovic, Z. Lj. [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Graham, W. G. [Centre for Plasma Physics, School of Mathematics and Physics, Queens University Belfast, BT7 1NN (United Kingdom)

    2011-11-15

    In this paper investigations of the voltage required to break down water vapor are reported for the region around the Paschen minimum and to the left of it. In spite of numerous applications of discharges in biomedicine, and recent studies of discharges in water and vapor bubbles and discharges with liquid water electrodes, studies of the basic parameters of breakdown are lacking. Paschen curves have been measured by recording voltages and currents in the low-current Townsend regime and extrapolating them to zero current. The minimum electrical breakdown voltage for water vapor was found to be 480 V at a pressure times electrode distance (pd) value of around 0.6 Torr cm ({approx}0.8 Pa m). The present measurements are also interpreted using (and add additional insight into) the developing understanding of relevant atomic and particularly surface processes associated with electrical breakdown.

  6. 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)

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

    1982-04-01

    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.

  7. Airborne Sunphotometry and Integrated Analyses of Dust, Other Aerosols, and Water Vapor in the Puerto Rico Dust Experiment (PRIDE)

    E-print Network

    aerosol layers). (d) Use these data in flight direction and planning. (e) Compare results to those/C obstructions (e.g., tail, antennas). 2. For A/C profiles, haze extinction spectra profiles (380 to 1020 or 1558-Apr: A/C Integration Planning, Fit Checks May: Pre-Campaign Sunphotometer Aerosol/Water Vapor Calibration

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

    SciTech Connect

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

    2005-05-01

    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.

  9. GPS Water Vapor Tomography: Description and First Results of The Escompte Field Experiment

    Microsoft Academic Search

    O. Bock; E. Doerflinger; F. Masson; A. Walpersdorf; J. van-Baelen; J. Tarniewicz; M. Troller; A. Somieski; A. Geiger; B. Bürki

    2002-01-01

    A dense network of 16 dual frequency GPS receivers has been operated for two weeks during June 2001 within a 20 km x 20 km area around Marseille, France, as part of the ESCOMPTE field campaign (http:\\/\\/medias.obs-mip.fr\\/escompte). The goal of the GPS experiment was to provide GPS data allowing for tomographic inversions and their validation within a well-documented observing period

  10. Remote sensing of water vapor features

    NASA Technical Reports Server (NTRS)

    Fuelberg, Henry E.

    1991-01-01

    The three major objectives of the project are outlined: (1) to describe atmospheric water vapor features as functions of space and time; (2) to evaluate remotely sensed measurements of water vapor content; and (3) to study relations between fine-scale water vapor fields and convective activity. Data from several remote sensors were used. The studies used the GOES/VAS, HIS, and MAMS instruments have provided a progressively finer scale view of water vapor features.

  11. Water vapor in protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Banzatti, Andrea

    2013-03-01

    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.

  12. 6, 80698095, 2006 Water vapor in Asian

    E-print Network

    Paris-Sud XI, Université de

    ACPD 6, 8069­8095, 2006 Water vapor in Asian summer monsoon region R. Zhan et al. Title Page Chemistry and Physics Discussions Intraseasonal variations of upper tropospheric water vapor in Asian;ACPD 6, 8069­8095, 2006 Water vapor in Asian summer monsoon region R. Zhan et al. Title Page Abstract

  13. WATER VAPOR FEEDBACK AND GLOBAL WARMING1

    Microsoft Academic Search

    Isaac M. Held; Brian J. Soden

    2000-01-01

    Abstract Water vapor is the dominant greenhouse gas, the most important gaseous source of infrared opacity in the atmosphere. As the concentrations of other greenhouse gases, particularly carbon dioxide, increase because of human activity, it is centrally important to predict how the water vapor distribution will be affected. To the extent that water vapor concentrations increase in a warmer world,

  14. 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

    Tellinghuisen, Joel

    2010-01-01

    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…

  15. Profiling atmospheric water vapor by microwave radiometry

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Wilheit, T. T.; Szejwach, G.; Gesell, L. H.; Nieman, R. A.; Niver, D. S.; Krupp, B. M.; Gagliano, J. A.; King, J. L.

    1983-01-01

    High-altitude microwave radiometric observations at frequencies near 92 and 183.3 GHz were used to study the potential of retrieving atmospheric water vapor profiles over both land and water. An algorithm based on an extended kalman-Bucy filter was implemented and applied for the water vapor retrieval. The results show great promise in atmospheric water vapor profiling by microwave radiometry heretofore not attainable at lower frequencies.

  16. Dual frequency water vapor radiometer

    NASA Astrophysics Data System (ADS)

    Xu, Peiyuan; Jin, Peiyu; Yao, Zhunliang; Fang, Zhenhe; Li, Mingxiang

    A steerable dual frequency water vapor radiometer (DFWVR) is developed. A pair of optimum frequencies, 20.60 and 31.65 GHz, is adopted. Each frequency channel has its own offset parabola antenna and Dicke switched receiver, but both channels are mounted on one rotatable pedestal and controlled by one microcomputer system. This DFWVR is capable of continuous, unattended operation. The sensitivity at 1 second time constant and the accuracy of the brightness temperature are 0.2 and 0.5 K, respectively, at both frequencies. It is expected to promote the excess path length corrections to be better than 1 cm for geodetic VLBI and GPS measurements.

  17. 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)

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

    2008-01-01

    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.

  18. The effect of forced ventilation through snow on the stable water isotope content of the vapor and the snow - an experiment

    NASA Astrophysics Data System (ADS)

    Berben, Sarah; Steen-Larsen, Hans Christian; Johnsen, Sigfus

    2010-05-01

    The stable water isotope signal throughout an ice core is a well known and often used proxy for past temperature reconstructions and is important in our understanding of the climate system. The knowledge about the post depositional processes influencing the isotope signal within the snowpack is therefore important. As wind blow across the snow surface micro high and low pressure areas arise because of sastrugies. These pressure differences create forced ventilation through the snowpack which then affect the interstitial mass exchange between water vapor and snow crystals and therefore the climatic signal stored in the snow. In order of understanding the physics behind this ongoing exchange, a combination of modeling and a controlled experiment has been set up. The process of forced ventilation -as it is believed to occur on Greenland and Antarctica- has then been simulated. The snow within this experiment is collected in Greenland during the new deep drilling project in NW Greenland (NEEM). Within this experiment, air with a known amount of moisture is pulled through a snow sample of different thicknesses. This sample has a known isotopic content and is kept at different sub-zero temperatures. The flow rate of the air has been controlled between 0,01 and 0,5 cm/s. After the interaction between the water vapor and the ice crystals the changes in both humidity and isotope signal are been studied. New in this research are the measurements of the isotope content with a Picarro WS-CRDS analyzer of the water vapour before and after the snow sample. Eventually, to estimate the magnitude of the effect of ventilation through snow on the stable isotope content of the water vapor, the results of the experiment are compared with the output from the computer model. This research will quantify the effect of forced ventilation on the mean isotope signal in the snow and its implications for the derived temperature signal from the water isotope ratio of the ice core as well as study the interstitial mass exchange between the air and the snow crystals.

  19. X-ray-induced water vaporization

    SciTech Connect

    Weon, B. M.; Lee, J. S.; Je, J. H. [X-ray Imaging Center, Department of Materials Science and Engineering,Pohang University of Science and Technology, San 31, Pohang 790-784 (Korea, Republic of); Fezzaa, K. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2011-09-15

    We present quantitative evidence for x-ray-induced water vaporization: water is vaporized at a rate of 5.5 pL/s with the 1-A-wavelength x-ray irradiation of {approx}0.1 photons per A{sup 2}; moreover, water vapor is reversibly condensed during pauses in irradiation. This result fundamentally suggests that photoionization induces vaporization. This phenomenon is attributed to surface-tension reduction by ionization and would be universally important in radiological and electrohydrodynamic situations.

  20. Eyeing the Sky's Water Vapor

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This image, and many like it, are one way NASA's Phoenix Mars Lander is measuring trace amounts of water vapor in the atmosphere over far-northern Mars. Phoenix's Surface Stereo Imager (SSI) uses solar filters, or filters designed to image the sun, to make these images. The camera is aimed at the sky for long exposures.

    SSI took this image as a test on June 9, 2008, which was the Phoenix mission's 15th Martian day, or sol, since landing, at 5:20 p.m. local solar time. The camera was pointed about 38 degrees above the horizon. The white dots in the sky are detector dark current that will be removed during image processing and analysis.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space

  1. Groundbased detection of middle atmospheric water vapor

    Microsoft Academic Search

    Paul Hartogh; Christopher Jarchow

    1995-01-01

    Groundbased microwave measurements are well suited for the intercomparison and validation of satellite data. A microwave heterodyne spectrometer, which can be used for this purpose has been developed at our institute. It measures the 22.235 GHz water vapor spectral emission and supplies water vapor profiles in the altitude range from 35 to 85 km with a time resolution of one

  2. Modeling Water Vapor in the Upper Troposphere and Lower Stratosphere

    Microsoft Academic Search

    Line Gulstad; Ivar S. A. Isaksen

    2007-01-01

    Upper troposphere and lower stratosphere (UTLS) water vapor is investigated using a general circulation model, the Community Atmosphere Model 3.0 (CAM3.0). Seasonal variability in UTLS water vapor, tempera- ture and zonal wind, based on model simulation results for the period 1991 - 2000, are analyzed. Results are validated against satellite data from the Halogen Occultation Experiment (HALOE) and ERA-40 reanalyzes

  3. Water Vapor Distribution in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Du, Fujun; Bergin, Edwin A.

    2014-09-01

    Water vapor has been detected in protoplanetary disks. In this work, we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust temperature and radiation field of the disk with a Monte Carlo method, and then solve the gas temperature distribution and chemical composition. The radiative transfer includes detailed treatment of scattering by atomic hydrogen and absorption by water of Ly? photons, since the Ly? line dominates the UV spectrum of accreting young stars. In a fiducial model, we find that warm water vapor with temperature around 300 K is mainly distributed in a small and well-confined region in the inner disk. The inner boundary of the warm water region is where the shielding of UV field due to dust and water itself become significant. The outer boundary is where the dust temperature drops below the water condensation temperature. A more luminous central star leads to a more extended distribution of warm water vapor, while dust growth and settling tends to reduce the amount of warm water vapor. Based on typical assumptions regarding the elemental oxygen abundance and the water chemistry, the column density of warm water vapor can be as high as 1022 cm-2. A small amount of hot water vapor with temperature higher than ~300 K exists in a more extended region in the upper atmosphere of the disk. Cold water vapor with temperature lower than 100 K is distributed over the entire disk, produced by photodesorption of the water ice.

  4. Simple Chemical Vapor Deposition Experiment

    ERIC Educational Resources Information Center

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  5. CO2 DIAL measurements of water vapor

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  6. Water vapor radiometry research and development phase

    NASA Technical Reports Server (NTRS)

    Resch, G. M.; Chavez, M. C.; Yamane, N. L.; Barbier, K. M.; Chandlee, R. C.

    1985-01-01

    This report describes the research and development phase for eight dual-channel water vapor radiometers constructed for the Crustal Dynamics Project at the Goddard Space Flight Center, Greenbelt, Maryland, and for the NASA Deep Space Network. These instruments were developed to demonstrate that the variable path delay imposed on microwave radio transmissions by atmospheric water vapor can be calibrated, particularly as this phenomenon affects very long baseline interferometry measurement systems. Water vapor radiometry technology can also be used in systems that involve moist air meteorology and propagation studies.

  7. Numerical and Experimental Quantification of coupled water and water vapor fluxes in very dry soils.

    NASA Astrophysics Data System (ADS)

    Madi, Raneem; de Rooij, Gerrit

    2015-04-01

    In arid and semi-arid regions with deep groundwater and very dry soils, vapor movement in the vadose zone may be a major component in the total water flux. Therefore, the coupled movement of liquid water, water vapor and heat transport in the unsaturated zone should be explicitly considered to quantify subsurface water fluxes in such regions. Only few studies focused on the importance of vapor water diffusion in dry soils and in many water flow studies in soil it was neglected. We are interested in the importance of water vapor diffusion and condensation in very dry sand. A version of Hydrus-1D capable of solving the coupled water vapor and heat transport equations will be used to do the numerical modeling. The soil hydraulic properties will be experimentally determined. A soil column experiment was developed with negligible liquid flow in order to isolate vapor flux for testing. We have used different values of initial water contents trying to generate different scenarios to assess the role of the water vapor transport in arid and semi-arid soils and how it changes the soil water content using different soil hydraulic parametrization functions. In the session a preliminary experimental and modelling results of vapor and water fluxes will be presented.

  8. Test and evaluation of water vapor radiometers

    NASA Technical Reports Server (NTRS)

    Moran, J.

    1980-01-01

    The accuracy of very long baseline interferometry in geodetic and astrometric applications is primarily limited by the propagation delays through the troposphere. The part of this delay that is most difficult to predict is due to atmospheric water vapor which can contribute up to about 40 cm of excess propagation path at microwave frequencies. The water vapor content in the atmosphere is variable and is not well correlated with surface meteorological variables. The brightness temperature measured near the transition of water vapor at 22.2 GHz and the propagation delay due to water vapor, or wet path length, are well correlated. This correlation is not perfect because the absorption coefficient and index of refraction do not have the same dependence on temperature and pressure.

  9. Water vapor recovery from plant growth chambers

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    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.

  10. Anthropogenic water vapor emissions in Tokyo

    NASA Astrophysics Data System (ADS)

    Moriwaki, Ryo; Kanda, Manabu; Senoo, Hiroshi; Hagishima, Aya; Kinouchi, Tsuyoshi

    2008-11-01

    Temporal and spatial variations in anthropogenic water vapor (AWV) emissions and anthropogenic heat (AH) in Tokyo were estimated using data from a geographic information system (GIS) and an energy-consumption database. The maximum value of AWV exceeded 500 W m-2 in summer in central Tokyo. Estimations of AWV were validated with field-measured data. The estimated and measured data agreed well, indicating that anthropogenic sources such as district cooling systems release large amounts of water vapor into the atmosphere.

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

    SciTech Connect

    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

    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.

  12. Vacuum distillation/vapor filtration water recovery

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    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.

  13. Characterization of Upper-Troposphere Water Vapor Measurements during AFWEX Using LASE

    Microsoft Academic Search

    Richard Ferrare; E. V. Browell; S. Ismail; S. A. Kooi; L. H. Brasseur; V. G. Brackett; M. B. Clayton; J. D. W. Barrick; G. S. Diskin; J. E. M. Goldsmith; B. M. Lesht; J. R. Podolske; G. W. Sachse; F. J. Schmidlin; David D. Turner; D. N. Whiteman; D. Tobin; L. M. Miloshevich; Henry E. Revercomb; B. B. Demoz; P. di Girolamo

    2004-01-01

    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 water vapor (UTWV) 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

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

    Microsoft Academic Search

    D. D. Turner; J. E. M. Goldsmith

    1998-01-01

    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

  15. High temperature measurement of water vapor absorption

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  16. 5 THE RADIATIVE FORCING DUE TO CLOUDS AND WATER VAPOR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter utilizes results from the spaceborne Earth Radiation Budget Experiment (ERBE), launched in 1984 aboard the NOAA-9 (National Oceanic and Atmospheric Agency) satellite, to summarize our understanding of the radiative forcing due to water vapor and clouds. The effect of clouds on the rad...

  17. 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

    Microsoft Academic Search

    1995-01-01

    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

  18. Persistent disparities in stratospheric water vapor measurements drive large uncertainties in the radiative forcing by lower stratospheric water vapor

    NASA Astrophysics Data System (ADS)

    Hurst, D. F.; Rosenlof, K. H.; Portmann, R. W.; Voemel, H.; Schiller, C.; Smith, J. B.; Thornberry, T. D.; Rollins, A. W.; Hall, E.; Jordan, A.; Oltmans, S. J.

    2011-12-01

    Lower stratospheric water vapor is a powerful attenuator of outgoing long wave radiation, hence its strong influence on the Earth's radiation budget. The radiative forcing by lower stratospheric water vapor is, however, quite uncertain because of significant disparities in lower stratospheric water vapor measurements by different instruments. Specifically, measurement discrepancies of 0.5 to 2 ppmv H2O (15 to 60%) between several well-established aircraft- and balloon-borne instruments have now persisted for almost two decades. The Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) in April 2011 provided not only a fresh opportunity to reexamine and reevaluate these persistent measurement discrepancies, but also to compare water vapor measurements by additional aircraft-based instrumentation. Here we compare the in situ measurements of lower stratospheric water vapor by five different instruments during MACPEX. Three of these instruments (Harvard water, FISH, and NOAA CIMS) were aboard the NASA WB-57 aircraft, while two (CFH and NOAA FPH) were launched on balloons. Substantial efforts were made to coordinate aircraft and balloon measurements in space and time, such that the aircraft would reach maximum altitude en route to the balloon rendezvous point, then both aircraft and balloon would descend together. Lower stratospheric water vapor measurements during MACPEX generally fall into two groups: CFH, NOAA FPH and FISH are in good agreement, while Harvard water and NOAA CIMS agree with each other but are significantly different than the other group. Differences between the two groups range from 0.5 to 1.0 ppmv (15 to 30%), with Harvard and NOAA CIMS mixing ratios consistently higher. Though these differences seem relatively large, they are smaller than some previously observed differences between the FPH/CFH and Harvard water. For example, Harvard stratospheric water vapor measurements during the 1993 CEPEX and 2006 CR-AVE campaigns were 1.5 and 2 ppmv greater, respectively, than the FPH/CFH measurements. Radiative transfer calculations employing the two disparate sets of water vapor profiles measured during MACPEX yield significantly different forcings for lower stratospheric water vapor. More accurate calculations are not possible until the ongoing measurement discrepancy is further reduced or eliminated. The smaller measurement discrepancies observed during MACPEX, though still statistically significant, have spawned renewed attempts to understand the root cause(s) of these measurement differences.

  19. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1986-01-01

    Heat transfer coefficients were measured using both dry air and air/water vapor mixtures in the same forced convection cooling test rig (jet array impingement configurations) with mass ratios of water vapor to air up to 0.23. The primary objective was to verify by direct experiment that selected existing methods for evaluation of viscosity and thermal conductivity of air/water vapor mixtures could be used with confidence to predict heat transfer coefficients for such mixtures using as a basis heat transfer data for dry air only. The property evaluation methods deemed most appropriate require as a basis a measured property value at one mixture composition in addition to the property values for the pure components.

  20. Observe animated satellite images of water vapor

    NSDL National Science Digital Library

    TERC. Center for Earth and Space Science Education

    2003-01-01

    This animation shows Earth science students how jet streams drive the movement of water vapor in the atmosphere. The introduction explains how the infrared images were taken from a satellite positioned about 8 kilometers above the Earth's surface. Students are instructed to observe how the jet streams (indicated by dark areas) are juxtaposed against areas of dense water vapor (indicated by light areas). Movie controls allow students to repeat, pause, or step through the animation, which can give students more time to analyze the images. Copyright 2005 Eisenhower National Clearinghouse

  1. Characterization of Upper Troposphere Water Vapor Measurements during AFWEX using LASE

    NASA Technical Reports Server (NTRS)

    Ferrare, R. A.; Browell, E. V.; Ismail, S.; Kooi, S.; Brasseur, L. H.; Brackett, V. G.; Clayton, M.; Barrick, J.; Linne, H.; Lammert, A.

    2002-01-01

    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 water vapor (UTWV) 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. We 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 UTWV measurements.

  2. Characterization of Advanced Avalanche Photodiodes for Water Vapor Lidar Receivers

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    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.

  3. Temperature and perturber dependences of water vapor line-broadening - Experiments at 183 GHz; calculations below 1000 GHz

    Microsoft Academic Search

    A. Bauer; M. Godon; M. Kheddar; J. M. Hartmann

    1989-01-01

    Measurements of linewidths of the 3(13)-2(20) H2O line at 183 GHz are presented. These include broadening by H2O, N2, O2, and Ar with the temperature dependence in the 300-390 K range. The room-temperature experiments are in good agreement with previous results. Systematic calculations of H2O line-broadening parameters of lines centered below 1000 GHz are also presented. These have been performed

  4. Processes Controlling Water Vapor in the Winter Arctic Tropopause Region

    NASA Technical Reports Server (NTRS)

    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

    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.

  5. Lateral mixing as a source of subtropical tropospheric water vapor

    E-print Network

    Pierrehumbert, Raymond

    Lateral mixing as a source of subtropical tropospheric water vapor R. T. Pierrehumbert Dept #12; Abstract It is hypothesized that the subtropical water vapor distribution results from that the Lagrangian model would also be useful in interpreting satellite water vapor data, and in diagnosing water

  6. Mars: Water Vapor Observations From the Viking Orbiters

    Microsoft Academic Search

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

    1977-01-01

    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

  7. Lateral mixing as a source of subtropical tropospheric water vapor

    E-print Network

    Pierrehumbert, Raymond

    Lateral mixing as a source of subtropical tropospheric water vapor R. T. Pierrehumbert Dept #12;Abstract It is hypothesized that the subtropical water vapor distribution results from that the Lagrangian model would also be useful in interpreting satellite water vapor data, and in diagnosing water

  8. Airborne Sun photometer measurements of aerosol optical depth and columnar water vapor during the Puerto Rico Dust Experiment and comparison with land, aircraft, and satellite measurements

    NASA Astrophysics Data System (ADS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey S.; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Smirnov, Alexander; Dubovik, Oleg; Welton, Ellsworth J.; Campbell, James R.; Wang, Jun; Christopher, Sundar A.

    2003-10-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km above sea level (asl) reproduce the vertical structure measured by coincident aircraft in situ measurements of total aerosol number concentration. AATS-6 extinction retrievals also agree with corresponding values derived from ground-based lidar measurements for altitudes above the trade inversion. The spectral behavior of AOD within specific layers beneath the top of the aircraft profile is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt, with mean Ångström wavelength exponents of ˜0.20. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in situ measurements agree to within ˜4% (0.13 g/cm2). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low-altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004-0.030 with coincident data obtained with an AERONET Sun/sky radiometer located on Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by ˜21%. AATS-6 AOD values measured during low-altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the Moderate-Resolution Imaging Spectroradiometer (MODIS), Total Ozone Mapping Spectrometer (TOMS), and GOES 8 Imager satellite sensors, with mixed results.

  9. GOES Water Vapor: 1995 Hurricane Season

    NSDL National Science Digital Library

    Greg Shirah

    1998-01-01

    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.

  10. Visualization of Atmospheric Water Vapor Data for SAGE

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    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.

  11. 21 CFR 868.1975 - Water vapor analyzer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    A water vapor analyzer is a device intended to measure the concentration of water vapor in a patient's expired gases by using techniques such as mass spectrometry. (b) Classification. Class I (general...

  12. 21 CFR 868.1975 - Water vapor analyzer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    A water vapor analyzer is a device intended to measure the concentration of water vapor in a patient's expired gases by using techniques such as mass spectrometry. (b) Classification. Class I (general...

  13. A passive microwave technique for profiling of atmospheric water vapor

    NASA Technical Reports Server (NTRS)

    Schaerer, G.; Wilheit, T. T.

    1979-01-01

    There is considerable interest in remote measurements of the vertical distribution of water vapor, particularly under cloud conditions. The net integrated amount of water vapor has been measured using the 22.235-GHz water vapor line (Staelin et al., 1975). Attempts to use this line for obtaining vertical distribution information have not been fruitful because of the weakness of absorption even at line center. The 183.310-GHz line is much stronger and thus provides a possibility of profiling water vapor. The paper presents a preliminary analysis of this possibility. A technique is described for retrieval of water vapor profiles from microwave radiometric measurements near the 183-GHz water vapor line, and weighting functions useful in the retrievals are developed. The results suggest that microwave radiometry near the 183-GHz water vapor line could yield interesting water vapor profiles, at least over oceans.

  14. Isotopic composition of stratospheric water vapor: Measurements and photochemistry

    E-print Network

    Isotopic composition of stratospheric water vapor: Measurements and photochemistry David G. Johnson. Photochemistry of Water Vapor Once air enters the stratosphere, the abundance of H 2 O increases through

  15. Stable isotopic composition of water vapor in the tropics

    NASA Astrophysics Data System (ADS)

    Lawrence, James Robert; Gedzelman, Stanley David; Dexheimer, Darielle; Cho, Hye-Khung; Carrie, Gordon D.; Gasparini, Robert; Anderson, Casey R.; Bowman, Kenneth P.; Biggerstaff, Mike I.

    2004-03-01

    Water vapor samples collected during tropical field experiments at Puerto Escondido, Mexico, near Kwajalein (KWAJEX), and near Key West, Florida (CAMEX 4), were analyzed for their stable isotope contents, 1H218O:1H216O and 2H1H16O:1H216O. Highest ?18O values approached isotopic equilibrium with seawater during quiescent weather or in regions of isolated or disorganized convection. Lowest ?18O values occurred in or downwind from regions of organized mesoscale weather disturbances and ranged as low as 15‰ below isotopic equilibrium with seawater. The mean ?18O value of vapor over the sea surface therefore decreases as storm activity and organization increases.

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

    SciTech Connect

    Koontz, A; Cadeddu, M

    2012-12-05

    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.

  17. Atmospheric absorption of terahertz radiation and water vapor continuum effects

    E-print Network

    Massachusetts at Lowell, University of

    Atmospheric absorption of terahertz radiation and water vapor continuum effects David M. Slocum a April 2013 Keywords: Water vapor Absorption Continuum Terahertz Spectroscopy a b s t r a c t The water vapor continuum absorption spectrum was investigated using Fourier Trans- form Spectroscopy

  18. Effect of higher water vapor content on TBC performance

    SciTech Connect

    Pint, Bruce A [ORNL; Haynes, James A [ORNL

    2012-01-01

    Coal gasification, or IGCC (integrated gasification combined cycle), is one pathway toward cleaner use of coal for power generation with lower emissions. However, when coal-derived synthesis gas (i.e., syngas) is burned in turbines designed for natural gas, turbine manufacturers recommend 'derating,' or lowering the maximum temperature, which lowers the efficiency of the turbine, making electricity from IGCC more expensive. One possible reason for the derating is the higher water vapor contents in the exhaust gas. Water vapor has a detrimental effect on many oxidation-resistant high-temperature materials. In a turbine hot section, Ni-base superalloys are coated with a thermal barrier coating (TBC) allowing the gas temperature to be higher than the superalloy solidus temperature. TBCs have a low thermal conductivity ceramic top coating (typically Y{sub 2}O{sub 3}-stabilized ZrO{sub 2}, or YSZ) and an oxidation-resistant metallic bond coating. For land-based gas turbines, the industry standard is air plasma sprayed (APS) YSZ and high velocity oxygen fuel (HVOF) sprayed NiCoCrAlY bond coatings. To investigate the role of higher water vapor content on TBC performance and possible mitigation strategies, furnace cycling experiments were conducted in dry O{sub 2} and air with 10% (typical with natural gas or jet fuel) or 50 vol% water vapor. Cycle frequency and temperature were accelerated to one hour at 1100 C (with 10 minute cooling to {approx}30 C between each thermal cycle) to induce early failures in coatings that are expected to operate for several years with a metal temperature of {approx}900 C. Coupons (16 mm diameter x 2 mm thick) of commercial second-generation single crystal superalloy CMSX4 were HVOF coated on both sides with {approx}125 {micro}m of Ni-22wt%Co-17Cr-12Al either with 0.7Y or 0.7Y-0.3Hf-0.4Si. One side was then coated with 190-240 {micro}m of APS YSZ. Coatings were cycled until the YSZ top coating spalled. Figure 2 shows the results of the initial phase of experiments. Compared to dry O{sub 2}, the addition of 10% water vapor decreased the lifetime of MCrAlY by {approx}30% for the conventional CMSX4 substrates. Higher average lifetimes were observed with Hf in the bond coating, but a similar decrease in lifetime was observed when water vapor was added. The addition of Y and La to the superalloy substrate did not change the YSZ lifetime with 10% water vapor. However, increasing water vapor content from 10 to 50% did not further decrease the lifetime of either bond coating with the doped superalloy substrate. Thus, these results suggest that higher water vapor contents cannot explain the derating of syngas-fired turbines, and other factors such as sulfur and ash from imperfect syngas cleanup (or upset conditions) need to be explored. Researchers continue to study effects of water vapor on thermally grown alumina scale adhesion and growth rate, and are looking for bond coating compositions more resistant to oxidation in the presence of water vapor.

  19. Water vapor measurements in the mesosphere from Mauna Loa over solar cycle 23

    NASA Astrophysics Data System (ADS)

    Nedoluha, Gerald E.; Gomez, R. Michael; Hicks, Brian C.; Wrotny, Jonathan E.; Boone, Chris; Lambert, Alyn

    2009-12-01

    The Water Vapor Millimeter-wave Spectrometer (WVMS) system has been making measurements from the Network for the Detection of Atmospheric Composition Change site at Mauna Loa, Hawaii (19.5°N, 204.4°E), since 1996, covering nearly the complete period of solar cycle 23. The WVMS measurements are compared with Halogen Occultation Experiment (HALOE) (1992-2005), Microwave Limb Sounder (MLS) (2004 to present), and Atmospheric Chemistry Experiment (ACE) Fourier transform spectrometer (2004 to present) measurements in the mesosphere. In the upper mesosphere Lyman ? radiation photodissociates water vapor; hence, water vapor in the upper mesosphere varies with the solar cycle. We calculate fits to the WVMS and HALOE water vapor data in this region using the Lasp Interactive Solar Irradiance Datacenter Lyman ? data set. This is, to our knowledge, the only published validation of the sensitivity of HALOE water vapor measurements to the solar cycle, and the HALOE and WVMS water vapor measurements show a very similar sensitivity to the solar cycle. Once the solar cycle variations are taken into account, the primary water vapor variations at all of these altitudes from 1992 to the present are an increase from 1992 to 1996, a maximum in water vapor in 1996, and small changes from 1997 to the present. Measurements from 2004 to 2008, which are available from WVMS, MLS, and ACE, show not only good agreement in interannual variations but also excellent agreement in their absolute measurements (to within better than 3%) of the water vapor mixing ratio from 50 to 80 km.

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

    Microsoft Academic Search

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

    2010-01-01

    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.

  1. Correlations between Water-Soluble Organic Aerosol and Water Vapor: A

    E-print Network

    Weber, Rodney

    Correlations between Water-Soluble Organic Aerosol and Water Vapor: A Synergistic Effect from and water vapor concentrations were highly correlated (average WSOCp-water vapor r ) 0.92); however lasted on average 19 h, were characterized by a wide range of WSOCp and water vapor concentrations

  2. Water Vapor, Condensed Water, and Crystal Concentration in Orographically Influenced Cirrus Clouds

    Microsoft Academic Search

    Johan Ström; Jost Heintzenberg

    1994-01-01

    Results are presented from measurements made with a counterflow virtual impactor (CVI) in cirriform clouds containing crystals with dimensions typically less than 30 m. Independent measurements of crystal number concentration and cloud water content are presented, and for the first time consistent instrumentation is used to measure both the cloud condensate and water vapor. The experiment was conducted over the

  3. Seasonal variability of mesospheric water vapor

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  4. The Water Vapor Abundance in Circumstellar Envelopes

    Microsoft Academic Search

    Eduardo González-Alfonso; José Cernicharo

    1999-01-01

    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

  5. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade inversion. Finally, AATS-6 AOD values measured during low altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the MODIS, TOMS, and GOES-8 Imager satellite sensors, with mixed results. These exercises highlight the need for continued satellite sensor comparison/validation studies to improve satellite AOD retrieval algorithms, and the usefulness of airborne sunphotometer measurements in the validation process.

  6. Water Vapor Effects on Silica-Forming Ceramics

    NASA Technical Reports Server (NTRS)

    Opila, E. J.; Greenbauer-Seng, L. (Technical Monitor)

    2000-01-01

    Silica-forming ceramics such as SiC and Si3N4 are proposed for applications in combustion environments. These environments contain water vapor as a product of combustion. Oxidation of silica-formers is more rapid in water vapor than in oxygen. Parabolic oxidation rates increase with the water vapor partial pressure with a power law exponent value close to one. Molecular water vapor is therefore the mobile species in silica. Rapid oxidation rates and large amounts of gases generated during the oxidation reaction in high water vapor pressures may result in bubble formation in the silica and nonprotective scale formation. It is also shown that silica reacts with water vapor to form Si(OH)4(g). Silica volatility has been modeled using a laminar flow boundary layer controlled reaction equation. Silica volatility depends on the partial pressure of water vapor, the total pressure, and the gas velocity. Simultaneous oxidation and volatilization reactions have been modeled with paralinear kinetics.

  7. Study of the 10 micron continuum of water vapor

    NASA Technical Reports Server (NTRS)

    Arefyev, V. N.; Dianov-Klokov, V. I.; Ivanov, V. M.; Sizov, N. I.

    1979-01-01

    Radiation attenuation by atmospheric water vapor is considered. A formula based on laboratory data is recommended for approximating continuous absorption in the spectra region in question. Data of full scale measurements and laboratory experiments are compared. It was concluded that only molecular absorption need be taken into account under clear atmospheric conditions during the warm part of the year, while in winter or in cloudy conditions, the effect of aerosol can be significant.

  8. AN OPERATIONAL G-BAND (183 GHZ) WATER VAPOR RADIOMETER

    Microsoft Academic Search

    Andrew L. Pazmany; Amherst MA

    2006-01-01

    ProSensing Inc. has developed a G-band (183 GHz, 1.5 mm wavelength) water vapor radiometer (GVR) for long-term, unattended measurement of low concentrations of atmospheric water vapor and liquid water. Precipitable water vapor (PWV) and liquid water path (LWP) are estimated from brightness temperatures measured by four double sideband receiver channels centered at 183.31plusmn1, plusmn3 and plusmn7, and plusmn14 GHz. A

  9. Atmospheric absorption of terahertz radiation and water vapor continuum effects

    E-print Network

    Massachusetts at Lowell, University of

    Atmospheric absorption of terahertz radiation and water vapor continuum effects David M. Slocum a vapor Absorption Continuum Terahertz Spectroscopy a b s t r a c t The water vapor continuum absorption. The absorption coefficient as a function of frequency was determined and compared with theoretical predictions

  10. Permeability of MDT chambers to water vapor

    E-print Network

    Palestini, S

    2003-01-01

    Tests of MDT chambers performed at the GIF facility and in the H8 test-beam area have shown relative high levels of water vapor contamination in the gas-mixture at the detector output. This effects significantly the drift properties of the MDTs. This note shows that amount of water observed is compatible with approximate estimates based on the permeability of Noryl, used in the tube end-plugs, and of EPDM, used in the O-rings of the on-chamber gas distribution.

  11. Atmospheric water vapor complexes and the continuum

    NASA Astrophysics Data System (ADS)

    Daniel, John S.; Solomon, Susan; Kjaergaard, Henrik G.; Schofield, Daniel P.

    2004-03-01

    Estimates of absorption optical depths for the bound complexes H2O-H2O and the sum of H2O-N2, H2O-O2, and H2O-Ar at visible and near-infrared wavelengths are compared to the same quantities calculated from a frequently used water continuum parameterization (MT_CKD) and from a theoretical far wing water vapor lineshape theory. The temperature dependences of some of these optical depths are also compared. The comparisons suggest qualitatively that water complexes may contribute to the continuum at these wavelengths, and show that the temperature dependence of the continuum might provide insight into the role of the complexes in the atmosphere. Because of the dearth of laboratory measurements of the continuum at these wavelengths, and because the current estimates for the equilibrium constants of these water vapor complexes remain highly uncertain, more observations are needed before the importance of water complexes can be accurately quantified.

  12. Transient water vapor at Europa's south pole.

    PubMed

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

    2014-01-10

    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

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

    SciTech Connect

    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

    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.

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

    NASA Technical Reports Server (NTRS)

    Sun, Jielun

    1993-01-01

    Results are presented of a test of the physically based total column water vapor retrieval algorithm of Wentz (1992) for sensitivity to realistic vertical distributions of temperature and water vapor. The ECMWF monthly averaged temperature and humidity fields are used to simulate the spatial pattern of systematic retrieval error of total column water vapor due to this sensitivity. The estimated systematic error is within 0.1 g/sq cm over about 70 percent of the global ocean area; systematic errors greater than 0.3 g/sq cm are expected to exist only over a few well-defined regions, about 3 percent of the global oceans, assuming that the global mean value is unbiased.

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

    NASA Astrophysics Data System (ADS)

    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

    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.

  16. Mass spectrometry for water vapor measurements in the UT/LS

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  17. Water vapor in the Martian atmosphere by SPICAM IR\\/Mars-Express

    Microsoft Academic Search

    Alexander Trokhimovskiy; Anna Fedorova; Oleg Korablev; Jean-Loup Bertaux; Eric Villard; Alexander V. Rodin

    2010-01-01

    Introduction SPICAM experiment along with PFS and OMEGA spectrometers on Mars Express has a capability to sound the water vapor in the atmosphere. The results of H2O measurements have been intensively published during last years [1-6]. Here we present the new analysis of SPICAM IR water vapor measurements, covering two Martian years. The near-IR channel of SPICAM experiment on Mars

  18. Water vapor measurements by Raman lidar during the ARM 1997 Water Vapor Intensive Observation Period

    Microsoft Academic Search

    D. D. Turner; D. N. Whiteman; K. D. Evans; S. H. Melfi; J. E. M. Goldsmith; G. K. Schwemmer

    1998-01-01

    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

  19. Ozone-Water Vapor Correlative Measurements as seen by lidar during the Measurements of Humidity in the Atmosphere and Validation Experiments (MOHAVE) 2009 Campaign

    NASA Astrophysics Data System (ADS)

    Leblanc, Thierry; McDermid, Stuart

    2010-05-01

    The MOHAVE 2009 campaign took place at the Jet Propulsion Laboratory (JPL) Table Mountain Facility on October 11-27, 2009. This campaign allowed a thorough evaluation of the JPL Raman Lidar measurements throughout the troposphere (ground to 20 km). Simultaneous and ozone measurements from the JPL co-located tropospheric and stratospheric ozone lidars allowed to study the relationship between ozone and water vapor up to 14-15 km at very short time scales. Results using both the nightly mean and the ten minute-integrated lidar profiles will be shown, revealing outstanding short-time variability, and allowing, for example, the precise tracking of several stratospheric dry intrusions and upper tropospheric troughs.

  20. Microcalorimetric investigation of water vapor adsorption on silica gel

    Microsoft Academic Search

    Hasan Demir; Moghtada Mobedi; Semra Ülkü

    2011-01-01

    Water vapor adsorption on silica gel was investigated using Tian–Calvet-type microcalorimetry. Differential heat of adsorption\\u000a data was obtained. The setup of microcalorimetry was used volumetric system to determine adsorption isotherms of water vapor–silica\\u000a gel. The Langmuir model was used in the interpretation of the adsorption data. The Clausius–Clapeyron diagram was also given.\\u000a Effective mass diffusivity of water vapor in the

  1. MEASUREMENT OF WATER VAPOR LOSS THROUGH HUMAN NAIL IN VIVO

    Microsoft Academic Search

    David Spruit

    1971-01-01

    A capsule is described which can be used for the measurement of the water vapor loss of the nail with the aid of the same instrumentation that has been used for the measurement of the water vapor loss of skin.The effective area of the described capsule has been determined applying an electric analog.The specific water permeability of the nail plate

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

    SciTech Connect

    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

    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.

  3. The relationship between clear sky water vapor and SST anomalies

    NASA Technical Reports Server (NTRS)

    Peterson, Thomas C.; Vonder Haar, Thomas H.

    1992-01-01

    The relationship between clear sky water vapor anomalies and the SST anomalies (SSTAs) was investigated with the purpose of providing data for evaluating the clear sky greenhouse effect predicted in many global warming scenarios, by statistically analyzing anomaly data sets of SST and the water vapor anomaly data (obtained by subtracting the mean value of the six years of data for a given month from the observed values). Results show that clear sky water vapor anomalies increase in association with increases in SSTAs. The clear sky water vapor anomalies high in the troposphere were also found to increase with increasing SSTA.

  4. Aircraft water vapor measurements utilizing an aluminum oxide hygrometer

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1974-01-01

    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.

  5. Aircraft water vapor measurements utilizing an aluminum oxide hygrometer

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1973-01-01

    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.

  6. Potassium vapor topping cycle gas-fired boiler water test

    Microsoft Academic Search

    D. B. Lloyd; R. H. Guymon; R. S. Holcomb

    1978-01-01

    The potassium vapor topping cycle is a concept for increasing the efficiency of the Rankine vapor cycle by raising the peak temperature by employing a potassium vapor cycle with a turbine inlet temperature of 1500 to 1600°F (815 to 870°C) in which the waste heat rejected from the condensing potassium vapor is transferred to boiling water and steam in a

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  8. Effect of Increased Water Vapor Levels on TBC Lifetime

    SciTech Connect

    Pint, Bruce A [ORNL; Garner, George Walter [ORNL; Lowe, Tracie M [ORNL; Haynes, James A [ORNL; Zhang, Ying [Tennessee Technological University

    2011-01-01

    To investigate the effect of increased water vapor levels on thermal barrier coating (TBC) lifetime, furnace cycle tests were performed at 1150 C in air with 10 vol.% water vapor (similar to natural gas combustion) and 90 vol.%. Either Pt diffusion or Pt-modified aluminide bond coatings were applied to specimens from the same batch of a commercial second-generation single-crystal superalloy and commercial vapor-deposited yttria-stabilized zirconia (YSZ) top coats were applied. Three coatings of each type were furnace cycled to failure to compare the average lifetimes obtained in dry O{sub 2}, using the same superalloy batch and coating types. Average lifetimes with Pt diffusion coatings were unaffected by the addition of water vapor. In contrast, the average lifetime of Pt-modified aluminide coatings was reduced by more than 50% with 10% water vapor but only slightly reduced by 90% water vapor. Based on roughness measurements from similar specimens without a YSZ coating, the addition of 10% water vapor increased the rate of coating roughening more than 90% water vapor. Qualitatively, the amount of {beta}-phase depletion in the coatings exposed in 10% water vapor did not appear to be accelerated.

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

  10. Water vapor column abundance retrievals during FIFE

    Microsoft Academic Search

    C. J. Bruegge; J. E. Conel; R. O. Green; J. S. Margolis; R. G. Holm; G. Toon

    1992-01-01

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. The authors report on the use of a sunphotometer to extract column

  11. Advanced Water Vapor Lidar Detection System

    NASA Technical Reports Server (NTRS)

    Elsayed-Ali, Hani

    1998-01-01

    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, leading to a decrease in the signal to noise ratio. Generally, errors in the measurement of water vapor with the DIAL method arise from both random and systematic sources. Systematic errors in DIAL measurements are caused by both atmospheric and instrumentation effects. The selection of the on-line alexandrite laser with a narrow linewidth, suitable intensity and high spectral purity, and its operation at the center of the water vapor lines, ensures minimum influence in the DIAL measurement that are caused by the laser spectral distribution and avoid system overloads. Random errors are caused by noise in the detected signal. Variability of the photon statistics in the lidar return signal, noise resulting from detector dark current, and noise in the background signal are the main sources of random error. This type of error can be minimized by maximizing the signal to noise ratio. The increase in the signal to noise ratio can be achieved by several ways. One way is to increase the laser pulse energy, by increasing its amplitude or the pulse repetition rate. Another way, is to use a detector system with higher quantum efficiency and lower noise, on the other hand, the selection of a narrow band optical filter that rejects most of the day background light and retains high optical efficiency is an important issue. Following acquisition of the lidar data, we minimize random errors in the DIAL measurement by averaging the data, but this will result in the reduction of the vertical and horizontal resolutions. Thus, a trade off is necessary to achieve a balance between the spatial resolution and the measurement precision. Therefore, the main goal of this research effort is to increase the signal to noise ratio by a factor of 10 over the current system, using a newly evaluated, very low noise avalanche photo diode detector and constructing a 10 MHz waveform digitizer which will replace the current CAMAC system.

  12. Operating a radio-frequency plasma source on water vapor.

    PubMed

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

    2009-08-01

    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(i) approximately = n(e), where n(i) is the positive ion density. But in the electronegative water plasma, quasineutrality requires n(i+) = n(i-) + n(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. PMID:19725651

  13. Roles of Oxygen and Water Vapor in the Oxidation of Halogen Terminated Ge(111) Surfaces

    SciTech Connect

    Sun, Shiyu; /Stanford U., Phys. Dept.; Sun, Yun; Liu, Zhi; Lee, Dong-Ick; Pianette, Piero; /SLAC, SSRL

    2006-12-18

    The initial stage of the oxidation of Cl and Br terminated Ge(111) surfaces is studied using photoelectron spectroscopy. The authors perform controlled experiments to differentiate the effects of different factors in oxidation, and find that water vapor and oxygen play different roles. Water vapor effectively replaces the halogen termination layers with the hydroxyl group, but does not oxidize the surfaces further. In contrast, little oxidation is observed for Cl and Br terminated surfaces with dry oxygen alone. However, with the help of water vapor, oxygen oxidizes the surface by breaking the Ge-Ge back bonds instead of changing the termination layer.

  14. Water recovery by catalytic treatment of urine vapor

    NASA Technical Reports Server (NTRS)

    Budininkas, P.; Quattrone, P. D.; Leban, M. I.

    1980-01-01

    The objective of this investigation was to demonstrate the feasibility of water recovery on a man-rated scale by the catalytic processing of untreated urine vapor. For this purpose, two catalytic systems, one capable of processing an air stream containing low urine vapor concentrations and another to process streams with high urine vapor concentrations, were designed, constructed, and tested to establish the quality of the recovered water.

  15. 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)

    Anderson, James G.

    2005-01-01

    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?

  16. Rate of water equilibration in vapor-diffusion crystallization: dependence on the residual pressure of air in the vapor space.

    PubMed

    DeTitta, G T; Luft, J R

    1995-09-01

    The kinetics of water equilibration in vapor-diffusion crystallization experiments are sensitive to the residual pressure of air in the vapor chamber. Experiments with sitting droplets of 10%(w/v) PEG, allowed to equilibrate with reservoirs of 20%(w/v) PEG, were conducted at pressures ranging from 80 to 760 mm Hg. Equilibrations were interrupted after one, four, five and seven days to assess their progress. Even down to the lowest pressures examined it was found that a decrease in pressure leads to an increase in the rate of equilibration. The residual pressure of air in the vapor chamber can be varied to tailor the time course of equilibration in macromolecular crystal growth experiments. PMID:15299810

  17. Aircraft Water Vapor Measurements Utilizing an Aluminum Oxide Hygrometer

    Microsoft Academic Search

    Ernest Hilsenrath

    1974-01-01

    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

  18. EXAMINING THE SPECTROSCOPY OF WATER VAPOR IN THE ATMOSPHERE

    E-print Network

    Petta, Jason

    EXAMINING THE SPECTROSCOPY OF WATER VAPOR IN THE ATMOSPHERE USING A VERTICAL CAVITY SURFACE EMITTING LASER Elise Pusateri, Professor Mark Zondlo, Minghui Diao #12;ATMOSPHERIC WATER VAPOR Greenhouse data acquisition for kHz sampling of atmosphere #12;ACKNOWLEDGEMENTS Professor Zondlo Minghui Diao

  19. A Satellite Survey Cloud Cover and Water Vapor

    E-print Network

    A Satellite Survey of Cloud Cover and Water Vapor in Northern Chile A study conducted for: Cerro, the frequency of occurrence of these conditions were determined from satellite observations of cloud cover brightness temperature to UTH 10 4.3 Computation of precipitable water vapor 11 4.4 Cloud detection

  20. Measurements of the vertical concentration profile of stratospheric water vapor

    Microsoft Academic Search

    N. Louisnard; A. Girard; G. Eichen

    1979-01-01

    The vertical concentration profile of water vapor is determined between the tropopause and an altitude of 40 km. Infrared water vapor emission was measured at sunset by a balloon-borne infrared absorption spectrometer at an altitude of approximately 40 km in May of 1973, 1974, and 1978, and the concentration profile was determined by an inversion process. The profile obtained for

  1. Evaluation of the GOME Water Vapor Climatology 1995–2002

    Microsoft Academic Search

    R. Lang; S. Casadio; A. N. Maurellis; M. G. Lawrence

    2007-01-01

    An accurate knowledge of the 3-D water vapor (WV) field is still limited, because of the limited capabilities of sensors in the past to cover the whole Earth’s surface and the lower part of the troposphere, as well as to measure over reasonably long time series. We show here water vapor total column retrieved from seven years of Global Ozone

  2. SPARC Data Initiative: Comparison of water vapor climatologies from

    E-print Network

    Wirosoetisno, Djoko

    SPARC Data Initiative: Comparison of water vapor climatologies from international satellite limb,824­11,846, doi:10.1002/jgrd.50752, 2013 SPARC Data Initiative: Comparison of water vapor climatologies from August 2013; accepted 10 August 2013; published 21 October 2013. [1] Within the SPARC Data Initiative

  3. Observations of atmospheric water vapor with the SAGE 2 instrument

    NASA Technical Reports Server (NTRS)

    Larsen, Jack C.; Mccormick, M. P.; Mcmaster, L. R.; Chu, W. P.

    1988-01-01

    The Stratospheric Aerosol and Gas Experiment 2 (SAGE 2) is discussed. The SAGE 2 instrument was a multichannel spectrometer that inferred the vertical distribution of water vapor, aerosols, nitrogen dioxide, and ozone by measuring the extinction of solar radiation at spacecraft sunrise/sunset. At altitudes above 20 km, the SAGE 2 and LIMS (Limb Infrared Monitor of the Stratosphere) data are in close agreement. The discrepancies below this altitude may be attributed to differences in the instruments' field of view and time of data acquisition.

  4. Measuring the water vapor above the SOFIA Observatory

    NASA Astrophysics Data System (ADS)

    Roellig, Thomas L.; Yuen, Lunming; Sisson, David; Meyer, Allan

    2010-07-01

    The SOFIA airborne observatory flies in the lower stratosphere above more than 99.9% of the Earth's water vapor. As low as this residual water vapor is, it will still affect SOFIA's infrared and sub-millimeter astronomical observations. As a result, a heterodyne instrument operating at 183 GHz will be used to measure the integrated water vapor overburden in flight. The accuracy of the measured precipitable water vapor must be 2 microns or better, 3 sigma, and measured at least once a minute. This presentation will cover the design and the measured laboratory performance of this instrument, and will discuss other options for determining the water vapor overburden during the SOFIA Early Science shared-risk period.

  5. On the use of GPS tomography to investigate water vapor variability during a Mistral/sea breeze event in southeastern France

    E-print Network

    Paris-Sud XI, Université de

    1 On the use of GPS tomography to investigate water vapor variability during a Mistral/sea breeze (GPS) tomography analyses of water vapor, complemented by high resolution numerical simulations experiment. This is the first time GPS tomography has been used to validate the three-dimensional water vapor

  6. Subtropical Water Vapor As a Mediator of Rapid Global Climate Change

    E-print Network

    Pierrehumbert, Raymond

    1 Subtropical Water Vapor As a Mediator of Rapid Global Climate Change Raymond T. Pierrehumbert vapor dynamics needed to address current issues regarding the possible role of water vapor changes of water vapor, the amount by which water vapor must change in order to cause a significant temperature

  7. Variations in Middle Atmospheric Water Vapor since 1991

    NASA Astrophysics Data System (ADS)

    Nedoluha, G. E.; Bevilacqua, R. M.; Gomez, R. M.; Hicks, B. C.; Randel, W. J.; Connor, B. J.; Russell, J. M.

    2006-05-01

    We present mesospheric water vapor measurements from the WVMS instruments at Lauder, New Zealand (1993-present) and Mauna Loa, Hawaii (1996-present), mesospheric and stratospheric measurements from HALOE (1991-2005), and stratospheric water vapor measurements from POAM III (1998-2005). There have been three major variations in these datasets that have persisted on timescales longer than the QBO. One of these variations is the solar cycle, which affects water vapor above ~60km, and makes the identification of secular trends particularly difficult in the upper mesosphere. There is also a well documented early 1990s increase, which persisted until ~1996 and affected water vapor throughout the middle atmosphere. In the lower mesosphere, below the altitude where solar cycle effects begin to become important, water vapor has remained nearly constant since ~1996. There was also a sudden decrease in water vapor in the lower stratosphere in 2001 which was, unlike the 1991-1996 increase, well correlated with tropical tropopause temperature changes. This decrease has persisted in the lower stratosphere, and the lower water vapor mixing ratios are beginning to appear in the upper stratosphere. We will document and quantify these effects with results from the WVMS, POAM, and HALOE measurements.

  8. Adsorption and Desorption of Nitrogen and Water Vapor by clay

    NASA Astrophysics Data System (ADS)

    Cui, Deshan; Chen, Qiong; Xiang, Wei; Huang, Wei

    2015-04-01

    Adsorption and desorption of nitrogen and water vapor by clay has a significant impact on unsaturated soil physical and mechanical properties. In order to study the adsorption and desorption characteristics of nitrogen and water vapor by montmorillonite, kaolin and sliding zone soils, the Autosorb-iQ specific surface area and pore size analyzer instrument of United State was taken to carry out the analysis test. The adsorption and desorption of nitrogen at 77K and water vapor at 293K on clay sample were conducted. The theories of BET, FHH and hydration energy were taken to calculate the specific surface, surface fractal dimension and adsorption energy. The results show that the calculated specific surface of water vapor by clay is bigger than nitrogen adsorption test because clay can adsorb more water vapor molecule than nitrogen. Smaller and polar water vapor molecule can access the micropore and then adsorb on the mineral surface and mineral intralayer, which make the mineral surface cations hydrate and the mineral surface smoother. Bigger and nonpolar nitrogen molecule can not enter into the micropore as water vapor molecule and has weak interaction with clay surface.

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

    NASA Technical Reports Server (NTRS)

    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

    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.

  10. Water Vapor around Sgr B2

    E-print Network

    J. Cernicharo; J. R. Goicoechea; J. R. Pardo; A. Asensio Ramos

    2006-01-16

    We have conducted a study combining H2O lines in two spectral regions. First, Infrared Space Observatory observations of several H2O thermal lines seen in absorption toward Sgr B2(M) at a spectral resolution of 35 kms^-1 have been analyzed. Second, an IRAM-30m telescope map of the para-H2O 3_13-2_20 line at 183.31 GHz, seen in emission, has also been obtained and analyzed. The H2O lines seen in absorption are optically thick and are formed in the outermost gas of the condensations in front of the far-IR continuum sources. They probe a maximum visual extinction of ~5 to 10 mag. Radiative transfer models indicate that these lines are quite insensitive to temperature and gas density, and that IR photons from the dust play a dominant role in the excitation of the involved H2O rotational levels. The water vapor abundance in the region is (1-2)x10^-5. The relatively low H2O/OH abundance ratio in the region, 2-4, is a signature of UV photon dominated surface layers traced by far-IR observations.

  11. Chemical reaction between water vapor and stressed glass

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

  12. Absorption of Water Vapor into Aqueous Solutions of Lithium Bromide

    NASA Astrophysics Data System (ADS)

    Takahara, Tsutomu; Hayashida, Atsushi; Yabase, Hajime; Hihara, Eiji; Saito, Takamoto

    Heat and mass transfer processes are experimentally investigated for the case of water absorption into aqueous solutions of lithium bromide flowing over a flat plate. Variables considered are inlet solution flow rate,concentration of an additive,and inclination angle of the plate. The use of 2-ethyl-1-hexanol as an additive results in about a four to five fold improvement in absorption rate. The occurrence of surface distrbances dose not has a direct connection with the solubility limit of the additive. The cause of the surface disturbances in the presence of additives is investigated through experiments for pool absorption By regulating the flow of water vapor,the form of the Marangoni convection can be controlled. A qualitative discussion of addictives in the role of inducing surface disturbances is presented.

  13. Shock-induced vaporization of zinc -- Experiments and numerical simulations

    SciTech Connect

    Chhabildas, L.C.; Brannon, R.M. [Sandia National Labs., Albuquerque, NM (United States). Ion Beam Generation Physics

    1996-12-31

    Prediction of the interaction between expanded vaporized debris and target materials for applications such as meteorite impact on space vehicles, ballistic penetration of armors, debris shield design, etc. demands an accurate treatment of the melting and vaporization process and the kinetics of liquid-vapor propagation. Historically, experimental efforts to understand high-pressure melting and vaporization have been hindered by unavailability of experimental launchers that are capable of speeds needed to induce vaporized states. Here, record-high impact speeds achieved using the Sandia HyperVelocity Launcher have permitted a systematic study of shock-induced full vaporization of zinc. Pressures up to 5.5 Mbar and temperatures as high as 39,000 K ({approximately} 3.4 eV) are induced in a thin zinc plate by impacting it with a tantalum flier at speeds up to 10.1 km/s. Such high pressures produce essentially full vaporization of the zinc because the thermodynamic release isentropes pass into the vapor dome near the critical point. To characterize vapor flow, the velocity history produced by stagnation of the zinc expansion products against a witness plate is measured with velocity interferometry. For each experiment, the time-resolved experimental interferometer record is compared with wavecode calculations using an analytical equation of state, called ANEOS, that is known to have performed quite well at lower impact speeds (less than {approximately} 7 km/s) where vaporization is negligible. Significant discrepancies between experiment and calculation are shown to exist under conditions of the more recent higher impact speeds in excess of 7 km/s where the release isentrope appears to pass near the critical point.

  14. Condensing phenomena of a single vapor bubble into subcooled water

    SciTech Connect

    Kamei, S. (Dept. of Mechanical Engineering, Univ. of Tokyo, Tokyo (JP)); Hirata, M. (Research Center for Advanced Science and Technology, Univ. of Tokyo, Tokyo (JP))

    1990-01-01

    This paper reports on experiments carried out to investigated direct contact condensation of saturated vapor bubbles introduced into a quiescent subcooled water environment. The experiments were performed for a range of pressures from atmospheric to 1 MPa, for subcooling from 10 to 70 K, and for initial bubble diameters of about 10 mm. Flow visualization by high-speed motion pictures was based on a frame-by-frame analysis. The authors show that the successive shapes of the bubbles during their collapse histories proceeded from a sphere to a hemisphere, to an ellipsoid, to a sphere, and finally to collapse. They show that the cavities of the bubbles during their collapse histories proceeded from the bottom to the top. The time to collapse increased with increasing pressure difference. The rising velocities of the bubbles were essentially constant, with an overall range of 20--25 cm/s.

  15. Stratospheric water vapor in the NCAR CCM2

    NASA Technical Reports Server (NTRS)

    Mote, Philip W.; Holton, James R.

    1992-01-01

    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.

  16. Fatigue Resistance of Asphalt Mixtures Affected by Water Vapor Movement 

    E-print Network

    Tong, Yunwei

    2013-11-08

    This dissertation has two key objectives: the first objective is to develop a method of predicting and quantifying the amount of water that can enter into a pavement system by vapor transport; the second objective is to ...

  17. University of Oregon: GPS-based Precipitable Water Vapor (PWV)

    SciTech Connect

    Vignola, F.; Andreas, A.

    2013-08-22

    A partnership with the University of Oregon and U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to collect Precipitable Water Vapor (PWV) data to compliment existing resource assessment data collection by the university.

  18. Water vapor and the dynamics of climate changes

    E-print Network

    Schneider, Tapio

    Water vapor is not only Earth's dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus ...

  19. University of Oregon: GPS-based Precipitable Water Vapor (PWV)

    DOE Data Explorer

    Vignola, F.; Andreas, A.

    A partnership with the University of Oregon and U.S. Department of Energy's National Renewable Energy Laboratory (NREL) to collect Precipitable Water Vapor (PWV) data to compliment existing resource assessment data collection by the university.

  20. Condensation of water vapor in the gravitational field

    SciTech Connect

    Gorshkov, V. G.; Makarieva, A. M.; Nefiodov, A. V., E-mail: anef@thd.pnpi.spb.ru [Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)

    2012-10-15

    Physical peculiarities of water vapor condensation under conditions of hydrostatic equilibrium are considered. The power of stationary dynamic air fluxes and the vertical temperature distribution caused by condensation on large horizontal scales are estimated.

  1. Isotopic composition of stratospheric water vapor: Measurements and photochemistry

    E-print Network

    Isotopic composition of stratospheric water vapor: Measurements and photochemistry David G. Johnson. In the following sections we will use Q to signify either E¥P Y or E¥Q Y and O to signify EHG Y . 3. Photochemistry

  2. Performance Modeling of an Airborne Raman Water Vapor Lidar

    NASA Technical Reports Server (NTRS)

    Whiteman, D. N.; Schwemmer, G.; Berkoff, T.; Plotkin, H.; Ramos-Izquierdo, L.; Pappalardo, G.

    2000-01-01

    A sophisticated Raman lidar numerical model had been developed. The model has been used to simulate the performance of two ground-based Raman water vapor lidar systems. After tuning the model using these ground-based measurements, the model is used to simulate the water vapor measurement capability of an airborne Raman lidar under both day-and night-time conditions for a wide range of water vapor conditions. The results indicate that, under many circumstances, the daytime measurements possess comparable resolution to an existing airborne differential absorption water vapor lidar while the nighttime measurement have higher resolution. In addition, a Raman lidar is capable of measurements not possible using a differential absorption system.

  3. Sensing atmospheric water vapor with the Global Positioning System

    Microsoft Academic Search

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

    1993-01-01

    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.

  4. High-Resolution Water Vapor Mapping from Interferometric Radar Measurements.

    PubMed

    Hanssen; Weckwerth; Zebker; Klees

    1999-02-26

    Spaceborne radar interferometric delay measurements were used to infer high-resolution maps of integrated atmospheric water vapor, which can be readily related to meteorological phenomena. Maps of the water vapor distribution associated with a precipitating cloud, a partly precipitating cold front, and horizontal convective rolls reveal quantitative measures that are not observed with conventional methods, and suggest that such radar observations can be used for forecasting and to study atmospheric dynamics. PMID:10037594

  5. Stratospheric water vapor increases over the past half-century

    Microsoft Academic Search

    K. H. Rosenlof; E.-W. Chiou; W. P. Chu; D. G. Johnson; K. K. Kelly; H. A. Michelsen; G. E. Nedoluha; E. E. Remsberg; G. C. Toon; M. P. McCormick

    2001-01-01

    Ten data sets covering the period 1954-2000 are analyzed to show a 1%\\/yr increase in stratospheric water vapor. The trend has persisted for at least 45 years, hence is unlikely the result of a single event, but rather indicative of long-term climate change. A long-term change in the transport of water vapor into the stratosphere is the most probable cause.

  6. Vapor-liquid equilibrium of amine-water systems 

    E-print Network

    Chun, Kil Whan

    1966-01-01

    VAPOR-LIQUID EQUILIBRIUM OF AMINE-WATER SYSTEMS A Thesis By KIL WHAN CHUN Submitted to the Graduate College of the Texas AS, M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1966 Major... Subject: Chemical Engineering VAPOR-LIQUID EQUILIBRIUM OF AMINE-WATER SYSTEMS A Thesis By KIL WHAN CHUN Approved as to style and content by: C airman of Committee) ead of D partment) (V ember) (Member ) (M ember) January 1966 ACKNOWLEDGMENTS...

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  8. Water-vapor pressure control in a volume

    NASA Technical Reports Server (NTRS)

    Scialdone, J. J.

    1978-01-01

    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.

  9. The vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of kerosene

    NASA Astrophysics Data System (ADS)

    Liang, Jin-Hu; Wang, Su; Zhang, Sheng-Tao; Yue, Lian-Jie; Fan, Bing-Cheng; Zhang, Xin-Yu; Cui, Ji-Ping

    2014-08-01

    In ground tests of hypersonic scramjet, the high-enthalpy airstream produced by burning hydrocarbon fuels often contains contaminants of water vapor and carbon dioxide. The contaminants may change the ignition characteristics of fuels between ground tests and real flights. In order to properly assess the influence of the contaminants on ignition characteristics of hydrocarbon fuels, the effect of water vapor and carbon dioxide on the ignition delay times of China RP-3 kerosene was studied behind reflected shock waves in a preheated shock tube. Experiments were conducted over a wider temperature range of 800-1 500K, at a pressure of 0.3 MPa, equivalence ratios of 0.5 and 1, and oxygen concentration of 20%. Ignition delay times were determined from the onset of the excited radical OH emission together with the pressure profile. Ignition delay times were measured for four cases: (1) clean gas, (2) gas vitiated with 10% and 20% water vapor in mole, (3) gas vitiated with 10% carbon dioxide in mole, and (4) gas vitiated with 10% water vapor and 10% carbon dioxide, 20% water vapor and 10% carbon dioxide in mole. The results show that carbon dioxide produces an inhibiting effect at temperatures below 1 300 K when ? = 0.5, whereas water vapor appears to accelerate the ignition process below a critical temperature of about 1 000 K when ? = 0.5. When both water vapor and carbon dioxide exist together, a minor inhibiting effect is observed at ? = 0.5, while no effect is found at ? = 1.0. The results are also discussed preliminary by considering both the combustion reaction mechanism and the thermophysics properties of the fuel mixtures. The current measurements demonstrate vitiation effects of water vapor and carbon dioxide on the autoignition characteristics of China RP-3 kerosene at air-like O2 concentration. It is important to account for such effects when data are extrapolated from ground testing to real flight conditions.

  10. Logarithmic radiative effect of water vapor and spectral kernels

    NASA Astrophysics Data System (ADS)

    Bani Shahabadi, Maziar; Huang, Yi

    2014-05-01

    Radiative 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.

  11. Water Vapor-Mediated Volatilization of High-Temperature Materials

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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.

  12. Measurements of atmospheric water vapor above Mauna Kea using an infrared radiometer

    E-print Network

    Naylor, David A.

    , the California Institute of Technology (CSO) opacity monitors, the JCMT 183GHz water vapor radiometer and Hilo-of-sight abundance of atmospheric water vapor is the multi-channel radiometric observation of the 183 GHz water vapor to the water vapor line transition at 183.31 GHz are fitted to a simple atmospheric emission model, whose

  13. Ocean Water Vapor and Cloud Burden Trends Derived from the Topex Microwave Radiometer

    E-print Network

    Ruf, Christopher

    Ocean Water Vapor and Cloud Burden Trends Derived from the Topex Microwave Radiometer Shannon Brown vapor and cloud liquid water for 1992-2005. The TMR climate data is analysed for trends. The global trend in precipitable water vapor is found to be 0.9 + 0.06 mm/decade. Regional precipitable water vapor

  14. Adsorption of water vapor on reservoir rocks. First quarterly report, January--March 1993

    SciTech Connect

    Not Available

    1993-07-01

    Progress is reported on: adsorption of water vapor on reservoir rocks; theoretical investigation of adsorption; estimation of adsorption parameters from transient experiments; transient adsorption experiment -- salinity and noncondensible gas effects; the physics of injection of water into, transport and storage of fluids within, and production of vapor from geothermal reservoirs; injection optimization at the Geysers Geothermal Field; a model to test multiwell data interpretation for heterogeneous reservoirs; earth tide effects on downhole pressure measurements; and a finite-difference model for free surface gravity drainage well test analysis.

  15. Gas phase reaction of sulfur trioxide with water vapor

    SciTech Connect

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

    1994-12-31

    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 SO3 with water vapor have previously been studied by Castleman and co-workers, Wang et al and Reiner and Arnold. Each of these studies was carried out in a flow reactor, with the first two studies performed at low pressure (1-10 Torr) and the latter from approx. 30 to 260 Torr. Each of these studies measured SO3 decays over a range of H2O vapor levels, obtaining data consistent with interpreting the reaction of gaseous SO3 and H2O as a bimolecular process. It is not clear why previous experimental studies failed to observe a nonlinear dependence of SO3 consumption on water vapor concentration. It is probable that sufficient water dimer exists in much of the Earth`s atmosphere to allow dimer reactions to participate in sulfuric acid vapor formation.

  16. Spectral probing of impact-generated vapor in laboratory experiments

    NASA Astrophysics Data System (ADS)

    Schultz, Peter H.; Eberhardy, Clara A.

    2015-03-01

    High-speed spectra of hypervelocity impacts at the NASA Ames Vertical Gun Range (AVGR) captured the rapidly evolving conditions of impact-generated vapor as a function of impact angle, viewpoint, and time (within the first 50 ?s). Impact speeds possible at the AVGR (<7 km/s) are insufficient to induce significant vaporization in silicates, other than the high-temperature (but low-mass) jetting component created at first contact. Consequently, this study used powdered dolomite as a proxy for surveying the evolution and distribution of chemical constituents within much longer lasting vapor. Seven separate telescopes focused on different portions of the impact vapor plume and were connected through quartz fibers to two 0.35 cm monochromaters. Quarter-space experiments reduced the thermal background and opaque phases due to condensing particles and heated projectile fragments while different exposure times isolated components passing through different the fields of view, both above and below the surface within the growing transient cavity. At early times (<5 ?s), atomic emission lines dominate the spectra. At later times, molecular emission lines dominate the composition of the vapor plume along a given direction. Layered targets and target mixtures isolated the source and reveal that much of the vaporization comes from the uppermost surface. Collisions by projectile fragments downrange also make significant contributions for impacts below 60° (from the horizontal). Further, impacts into mixtures of silicates with powdered dolomite reveal that frictional heating must play a role in vapor production. Such results have implications for processes controlling vaporization on planetary surfaces including volatile release, atmospheric evolution (formation and erosion), vapor generated by the Deep Impact collision, and the possible consequences of the Chicxulub impact.

  17. 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)

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

    2008-01-01

    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

  18. Measurement of Vapor Flow As an Important Source of Water in Dry Land Eco-Hydrology

    NASA Astrophysics Data System (ADS)

    Wang, Z.; He, Z.; Wang, Y.; Gao, Z.; Hishida, K.

    2014-12-01

    When the temperature of land surface is lower than that of air and deeper soils, water vapor gathers toward the ground surface where dew maybe formed depending on the prevailing dew point and wind speed. Some plants are able to absorb the dew and vapor flow while the soil can readily absorb both. Certain animals such as desert beetles and ants harvest the dew or fog for daily survival. Recently, it is also realized that the dew and vapor flow can be a life-saving amount of water for plant survival at the driest seasons of the year in arid and semi-arid regions. Researches are conducted to quantify the amount of near-surface vapor flow in arid and semi-arid regions in China and USA. Quantitative leaf water absorption and desorption functions were derived based on laboratory experiments. Results show that plant leaves absorb and release water at different speeds depending on species and varieties. The "ideal" native plants in the dry climates can quickly absorb water and slowly release it. This water-holding capacity of plant is characterized by the absorption and desorption functions derived for plant physiology and water balance studies. Field studies are conducted to measure the dynamic vapor flow movements from the atmosphere and the groundwater table to soil surface. Results show that dew is usually formed on soil and plant surfaces during the daily hours when the temperature gradients are inverted toward the soil surface. The amount of dew harvested using gravels on the soil surface was enough to support water melon agriculture on deserts. The vapor flow can be effectively intercepted by artificially seeded plants in semi-arid regions forming new forests. New studies are attempted to quantify the role of vapor flow for the survival of giant sequoias in the southern Sierra Nevada Mountains of California.

  19. VAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE FROM

    E-print Network

    VAPOR + LIQUID EQUILIBRIUM OF WATER, CARBON DIOXIDE, AND THE BINARY SYSTEM WATER + CARBON DIOXIDE the vapor-liquid equilibrium of water (between 323 and 573 K), carbon dioxide (between 230 and 290 K) and their binary mixtures (between 348 and 393 K). The properties of supercritical carbon dioxide were determined

  20. Assessment of the SAGE sampling strategy in the derivation of tropospheric water vapor distribution in a general circulation model

    SciTech Connect

    Zhang, M.H. [State Univ. of New York, Stony Brook, NY (United States)] [State Univ. of New York, Stony Brook, NY (United States)

    1995-06-01

    The Stratospheric Aerosol and Gas Experiment (SAGE) II has provided unprecedented information of water vapor distribution in the upper troposphere. For the purpose of comparison with output from climate models, the present study assesses the impact of the SAGE II sampling strategy on the tropospheric water vapor climatology in a general circulation model. Since water vapor is sampled only in {open_quotes}non-cloudy{close_quotes} regions in the SAGE strategy, the sampled water vapor concentration is smaller than the real climatology. This difference is associated with two factors. One is the water-vapor sampling frequency, the other is the humidity variability inside and outside the clouds. It is shown that maximum difference is at around 300 to 500 mb where it reaches up to 40% in the zonal mean humidity. 10 refs., 5 figs.

  1. The seasonal variation of water vapor and ozone in the upper mesosphere: Implications for vertical transport and ozone photochemistry

    Microsoft Academic Search

    Richard M. Bevilacqua; M. E. Summers; D. F. Strobel; John J. Olivero; Mark Allen

    1990-01-01

    Ground-based microwave techniques have supplied the only long-term measurements of water vapor in the mesosphere. The authors review the entire current data base, which consists of measurements obtained in three separate experiments over an 8-year period. The data from all three experiments indicate that the water vapor seasonal variation at mid-latitudes in the upper mesosphere is dominated by an annual

  2. Investigation of the Emission and Absorption Spectra of Water Vapor

    NASA Astrophysics Data System (ADS)

    Moskalenko, N. I.; Il'in, Yu. A.; Sadykov, M. S.

    2015-01-01

    Emission and absorption spectra of water vapor are measured and analyzed for temperatures 350-2500 K in the spectral range 0.57-25 ?m. Based on the developed mathematical model of radiative transfer, the parameters of spectral transmission functions of N2O vapors are obtained at different temperatures. Practical application of the obtained radiative characteristics is considered for solving problems of radiative heat exchange in high-temperature media and designing optoelectronic systems intended for monitoring of aero carriers.

  3. Global atmospheric mass, surface pressure, and water vapor variations

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Christy, John R.; Olson, Jerry G.

    1988-01-01

    Variations in the hydrological cycle and the water vapor content of the atmosphere form a vital part of the "greenhouse" feedback mechanism that can substantially enhance perturbations in the atmosphere arising from changes in forcing, such as those associated with increases in the carbon dioxide content of the atmosphere. An analysis is therefore made of the mean annual cycle interannual variability and trends in global-scale water vapor content of the atmosphere for December 1978 through December 1985, using global analyses from the European Centre for Medium Range Weather Forecasts. Since the variations in total atmospheric mass are almost entirely due to water vapor, two entirely independent global measures of the water vapor content can be compared. These are the total surface pressure due to water vapor from humidity analyses and the total surface pressure itself. For the mean annual cycle these show excellent agreement, and the analyses are therefore compatible with the constraint that the total mass of dry air is conserved. However, it appears that both the interannual variability and trends in water vapor are sufficiently small that they are lost in the noise level of the data, A new estimate of the total mass of the atmosphere is 5.1361×1018 kg for the annual mean, corresponding to a mean surface pressure of 984.43 mbar. It ranges from 5.1352×1018 kg in January to 5.1371×1018 kg in July, owing to the annual cycle in global water vapor which has an amplitude of 1.0×1015 kg (0.2 mbar). The total mass of dry air is estimated to be 5.123×1018 kg (or 981.9 mbar). Also presented is the partitioning of the mass for both the total and the water vapor into the contributions from each hemisphere and as a function of latitude. Mean annual surface pressures in the northern and southern hemispheres are found to be 981.92 and 986.93 mbar, respectively. Monthly mean hemispheric fluctuations in surface pressures of ±1 mbar are not uncommon and tend to be reflected by opposite anomalies in the other hemisphere (consistent with conservation of mass), but the residual in the global monthly mean is of the order of 0.1 mbar. Since this is greater than the magnitude of the possible signal in water vapor surface pressure, the available evidence indicates that the analyzed global monthly anomalies are mostly noise.

  4. Global atmospheric mass, surface pressure, and water vapor variations

    NASA Astrophysics Data System (ADS)

    Trenberth, Kevin E.; Christy, Johan R.; Olson, Jerry G.

    1987-12-01

    Variations in the hydrological cycle and the water vapor content of the atmosphere form a vital part of the "greenhouse" feedback mechanism that can substantially enhance perturbations in the atmosphere arising from changes in forcing, such as those associated with increases in the carbon dioxide content of the atmosphere. An analysis is therefore made of the mean annual cycle, interannual variability and trends in global-scale water vapor content of the atmosphere for December 1978 through December 1985, using global analyses from the European Centre for Medium Range Weather Forecasts. Since the variations in total atmospheric mass are almost entirely due to water vapor, two entirely independent global measures of the water vapor content can be compared. These are the total surface pressure due to water vapor from humidity analyses and the total surface pressure itself. For the mean annual cycle these show excellent agreement, and the analyses are therefore compatible with the constraint that the total mass of dry air is conserved. However, it appears that both the interannual variability and trends in water vapor are sufficiently small that they are lost in the noise level of the data. A new estimate of the total mass of the atmosphere is 5.1361×1018 kg for the annual mean, corresponding to a mean surface pressure of 984.43 mbar. It ranges from 5.1352×1018 kg in January to 5.1371×1018 kg in July, owing to the annual cycle in global water vapor which has an amplitude of 1.0×1015 kg (0.2 mbar). The total mass of dry air is estimated to be 5.123×1018 kg (or 981.9 mbar). Also presented is the partitioning of the mass for both the total and the water vapor into the contributions from each hemisphere and as a function of latitude. Mean annual surface pressures in the northern and southern hemispheres are found to be 981.92 and 986.93 mbar, respectively. Monthly mean hemispheric fluctuations in surface pressures of ±1 mbar are not uncommon and tend to be reflected by opposite anomalies in the other hemisphere (consistent with conservation of mass), but the residual in the global monthly mean is of the order of 0.1 mbar. Since this is greater than the magnitude of the possible signal in water vapor surface pressure, the available evidence indicates that the analyzed global monthly anomalies are mostly noise.

  5. WATER VAPOR AND THE DYNAMICS OF CLIMATE CHANGES

    E-print Network

    O'Gorman, Paul

    the global circulation of the atmosphere and thus climate. The latent heat released when atmospheric water circulation of the atmosphere and thus climate. Here we present an overview of how latent heat release affects) is controlled. [3] Here we present an overview of dynamic effects of water vapor in the global circulation

  6. What regulates the annual cycle of stratospheric water vapor?

    NASA Astrophysics Data System (ADS)

    Jucker, Martin; Gerber, Edwin

    2015-04-01

    Stratospheric water vapor is a potent greenhouse gas and active chemical tracer. Most of the stratosphere is well below saturation due to freeze drying at the tropical cold point -- the coldest region of the lower stratosphere where most air enters the middle atmosphere. The leading mode of variability of the tropical cold point is an annual cycle, despite the semi-annual cycle of radiative forcing in the tropics. This causes the stratospheric water vapor mixing ratio to follow a similar annual cycle, even remotely from the entry point, the so-called tape recorder. We develop an idealized GCM to investigate the origin of the annual cycle in the tropical cold point, with a particular focus on the interaction between dynamics and radiation. By varying the surface conditions of the model, we first show that planetary scale asymmetries in the midlatitude troposphere drive the annual cycle in the cold point. Both large scale topography and land sea contrast are important, influencing synoptic and planetary scale wave forcing. We then probe the impact of water vapor on the stratospheric circulation by comparing fully interactive integrations of the model to companion integrations where the coupling between the circulation and water vapor is disconnected. Our findings have implications in estimating the impacts of stratospheric water vapor feedbacks on decadal time scales and sensitivities to climate change.

  7. Effects of water vapor fluctuations on atmospheric limb radiance structure

    NASA Astrophysics Data System (ADS)

    Quang, Carine; Rialland, Valérie; Roblin, Antoine

    2010-10-01

    Airborne infrared limb-viewing sensors may be used as surveillance devices in order to detect dim military targets. These systems' performances are limited by the inhomogeneous background in the sensor field of view which impacts strongly on target detection probability. Consequently, the knowledge of the radiance small-scale angular fluctuations and their statistical properties is required to assess the sensors' detection capacity. In the stratosphere and in clear-sky conditions, the structured background is mainly due to inertia-gravity-wave and turbulence-induced temperature and density spatial fluctuations. Moreover, in the particular case of water vapor absorption bands, the mass fraction fluctuations play a non negligible role on the radiative field. Thereby, considering as a first approximation the temperature field and the water vapor field as stationary stochastic processes, the radiance autocorrelation function (ACF) can be expressed as a function of the temperature ACF and the water vapor mass fraction ACF. This paper presents the model developed to compute the two-dimensional radiance angular ACF. This model requires the absorption coefficients and their temperature derivatives, which were calculated by a line-by-line code dedicated to water vapor absorption bands. An analytical model was also developed for a simple homogeneous case, in order to validate the average values and the radiance fluctuation variance. The numerical model variance and variance distribution are also compared to SAMM2 outputs, the AFRL radiance structure computation code. The influence of water vapor fluctuations on radiance fluctuations is also discussed.

  8. Experimental Study of Water Droplet Vaporization on Nanostructured Surfaces

    NASA Astrophysics Data System (ADS)

    Padilla, Jorge, Jr.

    This dissertation summarizes results of an experimental exploration of heat transfer during vaporization of a water droplet deposited on a nanostructured surface at a temperature approaching and exceeding the Leidenfrost point for the surface and at lower surface temperatures 10-40 degrees C above the saturated temperature of the water droplet at approximately 101 kPa. The results of these experiments were compared to those performed on bare smooth copper and aluminum surfaces in this and other studies. The nanostructured surfaces were composed of a vast array of zinc oxide (ZnO) nanocrystals grown by hydrothermal synthesis on a smooth copper substrate having an average surface roughness of approximately 0.06 micrometer. Various nanostructured surface array geometries were produced on the copper substrate by performing the hydrothermal synthesis for 4, 10 and 24 hours. The individual nanostructures were randomly-oriented and, depending on hydrothermal synthesis time, had a mean diameter of about 500-700 nm, a mean length of 1.7-3.3 micrometers,and porosities of approximately 0.04-0.58. Surface wetting was characterized by macroscopic measurements of contact angle based on the droplet profile and calculations based on measurements of liquid film spread area. Scanning electron microscope imaging was used to document the nanoscale features of the surface before and after the experiments. The nanostructured surfaces grown by hydrothermal synthesis for 4 and 24 hours exhibited contact angles of approximately 10, whereas the surfaces grown for 10 hours were superhydrophilic, exhibiting contact angles typically less than 3 degrees. In single droplet deposition experiments at 101 kPa, a high-speed video camera was used to document the droplet-surface interaction. Distilled and degassed water droplets ranging in size from 2.5-4.0 mm were deposited onto the surface from heights ranging from approximately 0.2-8.1 cm, such that Weber numbers spanned a range of approximately 0-99. Heat transfer coefficients were determined from thermal measurements in the test apparatus. All experiments were conducted inside an ISO Class 5 clean room enclosure. It was observed that when a liquid water droplet impinged upon the ZnO nanostructured at surface temperatures less than 140 degrees C, the nominally spherical droplet spread into a thin film over the surface. The film thickness depended on many parameters but in general it measured approximately 100-400 micrometers. As a result, it was found that the droplet evaporated by film evaporation without initiating nucleate boiling. At wall superheat levels of 10-20 degrees C, it was found in some cases that the heat transfer coefficients were nearly 4 times greater than for those of nucleate boiling at the same superheat level. For these conditions, no bubble nucleation was observed visually, and, nevertheless, extremely high heat transfer coefficients resulting from rapid evaporation of the thin liquid film formed by the spreading droplet were observed. At high wall superheat levels, the vaporization process exhibited Leidenfrost droplet vaporization. The extreme wetting of the nanostructured surfaces resulted in high Leidenfrost transition temperatures in the range of 310-376 degrees C, among the highest in the literature, exceeding those exhibited by bare metal surfaces by 100 degrees C or more. The Leidenfrost transition was detected from a recording of the acoustic signal generated from each experiment during the deposition and subsequent evaporation process. It was defined as the first point for which there is no disturbance to the acoustical signal in the form of a sizzling sound beyond the initial violent popping generated during the droplet deposition. The results document a trend of increasing Leidenfrost temperature with decreasing contact angle, which is consistent with earlier studies. The results of this study are compared with earlier work in this area and the implications for applications are discussed.

  9. Experiences with HANGMAN: a macromolecular hanging drop vapor diffusion technique

    Microsoft Academic Search

    Joseph R. Luft; Vivian Cody; George T. Detitta

    1992-01-01

    A variant of the hanging drop vapor diffusion microtechnique is presented which uses an adhesive tape surface to simultaneously support protein droplets and seal reservoir solutions. The tape is supported on a teflon and plexiglas framework during setup of the experiment. The framework containing the protein solution droplets can be inverted over a standard tissue culture plate conyaining reservoirs of

  10. 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)

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

    2012-07-01

    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.

  11. Analysis of the global ISCCP TOVS water vapor climatology

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

    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.

  12. Interpretation of HALOE, ACE, and MIPAS Water Vapor and Methane Data in the Equatorial Upper Stratosphere

    NASA Astrophysics Data System (ADS)

    Wrotny, J. E.; Nedoluha, G. E.; Boone, C.; Stiller, G. P.

    2008-12-01

    Water vapor and methane data measured by the Halogen Occultation Experiment (HALOE),the Atmospheric Chemistry Experiment (ACE), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) are used to study time series of H2O+2*CH4 in the equatorial upper stratosphere. Recent studies [e.g. Nassar et. al., 2005] have shown that, generally, H2O+2*CH4 is a conserved quantity. However, multi-year time series of H2O+2*CH4 show unexpected time variations which occur even during periods of relative long- term stability in water vapor and methane entering the stratosphere. These variations are evident in time series for each dataset, are QBO and seasonal in nature, and peak near 2 mb with a magnitude of 2-3 % of the H2O+2*CH4 mixing ratio. The H2O+2*CH4 time variations are anti-correlated with the methane variations suggesting a connection to local transport. We address the potential causes of the variations in H2O+2*CH4 and rule out several possibilities such as QBO and seasonal (e.g. tape recorder) variations from the lower stratosphere and variations in water vapor from photodissociation. By using a common analysis approach to study water vapor and methane variations [e.g. Hansen and Robinson, 1989; Remsberg et. al., 1996], we calculate beta, also called the net chemical yield factor of water vapor from methane. Modeling studies of water vapor chemistry in the stratosphere [LeTexier et. al., 1988] found beta values >2 in the upper stratosphere and suggested that oxidation of molecular hydrogen must also be considered in the water vapor budget to explain these values. Using several approaches, we find beta values consistently >2 over the entire equatorial upper stratosphere using HALOE, ACE and MIPAS data. We then use this value of beta to calculate a time series which should better reflect the tropopause entry levels of water vapor and methane, and discuss the implications of this for the early 1990s increase in water vapor.

  13. Precipitable Water Vapor from GPS in Antarctica: Opportunities from the TAMDEF GPS Network, Victoria Land

    Microsoft Academic Search

    G. E. Vazquez; D. A. Grejner

    2005-01-01

    An experiment was carried out in order to estimate Precipitable Water Vapor (PWV) using the Global Positioning System (GPS) data collected by the Trans Antarctic Mountain Deformation Network, Victoria Land in Antarctica. TAMDEF is the OSU and US Geological Survey joint project sponsored by National Science Foundation (NSF). Estimation of PWV from the GPS data could play a crucial role

  14. Stratospheric water vapor, nitrogen dioxide, nitric acid and ozone measurements deduced from spectroscopic observations

    Microsoft Academic Search

    André Girard; Nicole Louisnard

    1984-01-01

    Solar infrared absorption spectra for water vapor, nitrogen dioxide, nitric acid and ozone were recorded during the LIMS (Limb Infrared Monitor of the Stratosphere) lifetime. Mixing ratio profiles were deduced from a balloon experiment at 40 km on 24 April 1979 at 31 degrees N. Latitudinal variations of the column densities were deduced from an aircraft, near 11.5 km, during

  15. Tracking Water Vapor in the Winter High Arctic using the Microwave Humidity Sounder

    NASA Astrophysics Data System (ADS)

    Duck, T. J.; Lesins, G. B.; Drummond, J. R.

    2010-12-01

    The cold and dry conditions during the darkness of the winter High Arctic have been a challenge for the retrieval of tropospheric water vapor amounts from satellites. Water vapor remains the most important greenhouse gas even in these dry conditions and so its variability has a direct bearing on the radiative forcing at the surface. The presence of the surface-based temperature inversion helps to amplify the response of the surface temperature to fluctuations in water vapor column. The ability to track the movement and magnitude of water vapor intrusions into the Arctic has important operational forecast as well as climate implications associated with rapid Arctic warming and sea ice loss. The water vapor field also determines the cloud and precipitation development. The first high temporal and high spatial resolution satellite retrievals of precipitable water in the winter High Arctic without interference from clouds and precipitation were done by Melsheimer and Heygster (2008) using the 5 AMSU-B microwave channels near the strong 183 GHz water vapor line and the window channel at 150 GHz. We have applied their algorithm to the Microwave Humidity Sounder (MHS) that is installed on the NOAA-18, -19 and MetOp-A satellites. The MHS is the next generation instrument replacing the AMSU-B. The retrievals have a sensitivity of less than 0.5 mm of column water with a nadir spatial resolution of 17 km. Numerous passes over the entire Arctic take place every day providing a high resolution map of the distribution of water vapor over the entire Arctic without masking from clouds or precipitation. The calibration procedures, including comparisons with multiple ground-based microwave radiometers, will be presented along with results of the water vapor tracking experiments for the 2009-2010 winter season in the High Arctic. Movies depicting the movement and evolution of the water vapor column will be shown. These show frequent intrusions of lobes of moisture associated with transient cyclogenesis near the Aleutian and Icelandic lows and the removal of moisture by atmospheric transport out of the Arctic rather than solely by precipitation.

  16. Using Absolute Humidity and Radiochemical Analyses of Water Vapor Samples to Correct Underestimated Atmospheric Tritium Concentrations

    SciTech Connect

    Eberhart, C.F.

    1999-06-01

    Los Alamos National Laboratory (LANL) emits a wide variety of radioactive air contaminants. An extensive ambient air monitoring network, known as AIRNET, is operated on-site and in surrounding communities to estimate radioactive doses to the public. As part of this monitoring network, water vapor is sampled continuously at more than 50 sites. These water vapor samples are collected every two weeks by absorbing the water vapor in the sampled air with silica gel and then radiochemically analyzing the water for tritium. The data have consistently indicated that LANL emissions cause a small, but measurable impact on local concentrations of tritium. In early 1998, while trying to independently verify the presumed 100% water vapor collection efficiency, the author found that this efficiency was normally lower and reached a minimum of 10 to 20% in the middle of summer. This inefficient collection was discovered by comparing absolute humidity (g/m{sup 3}) calculated from relative humidity and temperature to the amount of water vapor collected by the silica gel per cubic meter of air sampled. Subsequent experiments confirmed that the elevated temperature inside the louvered housing was high enough to reduce the capacity of the silica gel by more than half. In addition, their experiments also demonstrated that, even under optimal conditions, there is not enough silica gel present in the sampling canister to absorb all of the moisture during the higher humidity periods. However, there is a solution to this problem. Ambient tritium concentrations have been recalculated by using the absolute humidity values and the tritium analyses. These recalculated tritium concentrations were two to three times higher than previously reported. Future tritium concentrations will also be determined in the same manner. Finally, the water vapor collection process will be changed by relocating the sampling canister outside the housing to increase collection efficiency and, therefore, comparability to the true ambient concentrations of tritium.

  17. An opacity-sampled treatment of water vapor

    NASA Technical Reports Server (NTRS)

    Alexander, David R.; Augason, Gordon C.; Johnson, Hollis R.

    1989-01-01

    Although the bands of H2O are strong in the spectra of cool stars and calculations have repeatedly demonstrated their significance as opacity sources, only approximate opacities are currently available, due both to the difficulty of accounting for the millions of lines involved and to the inadequacy of laboratory and theoretical data. To overcome these obstacles, a new treatment is presented, based upon a statistical representation of the water vapor spectrum derived from available laboratory data. This statistical spectrum of water vapor employs an exponential distribution of line strengths and random positions of lines whose overall properties are forced to reproduce the mean opacities observed in the laboratory. The resultant data set is then treated by the opacity-sampling method exactly as are all other lines, both molecular and atomic. Significant differences are found between the results of this improved treatment and the results obtained with previous treatments of water-vapor opacity.

  18. Water vapor-nitrogen absorption at CO2 laser frequencies

    NASA Technical Reports Server (NTRS)

    Peterson, J. C.; Thomas, M. E.; Nordstrom, R. J.; Damon, E. K.; Long, R. K.

    1979-01-01

    The paper reports the results of a series of pressure-broadened water vapor absorption measurements at 27 CO2 laser frequencies between 935 and 1082 kaysers. Both multiple traversal cell and optoacoustic (spectrophone) techniques were utilized together with an electronically stabilized CW CO2 laser. Comparison of the results obtained by these two methods shows remarkable agreement, indicating a precision which has not been previously achieved in pressure-broadened studies of water vapor. The data of 10.59 microns substantiate the existence of the large (greater than 200) self-broadening coefficients determined in an earlier study by McCoy. In this work, the case of water vapor in N2 at a total pressure of 1 atm has been treated.

  19. Water vapor - The wet blanket of microwave interferometry

    NASA Technical Reports Server (NTRS)

    Resch, G. M.

    1980-01-01

    The various techniques that utilize microwave interferometry could be employed to determine distances of several thousand kilometers with an accuracy of 1 cm or 2 cm. Such measurements would be useful to obtain new knowledge of earth dynamics, greater insight into fundamental astronomical constants, and the ability to accurately navigate a spacecraft in interplanetary flight. There is, however, a basic problem, related to the presence of tropospheric water vapor, which has to be overcome before such measurements can be realized. Differing amounts of water vapor over the interferometer stations cause errors in the differential time of arrival which is the principal observable quantity. Approaches for overcoming this problem are considered, taking into account requirements for water vapor calibration to support interferometric techniques.

  20. Computation of infrared cooling rates in the water vapor bands

    NASA Technical Reports Server (NTRS)

    Chou, M.-D.; Arking, A.

    1980-01-01

    A fast and accurate method is developed for calculating the infrared radiative terms due to water vapor - specifically, the atmospheric cooling rates. The accuracy is achieved by avoiding the constraints of band models and working directly with the absorption coefficient, which is a function of temperature and pressure as well as wavenumber. The method is based on calculation of an equivalent water vapor amount between atmospheric pressure levels and a table look-up procedure. Compared to line-by-line calculations, the present method has errors up to 4% of the maximum cooling rate. The use of a scaling factor, based on the far-wing approximation, limits the applicability of the method to the troposphere and lower stratosphere, where the line wings are responsible for most of the radiative cooling associated with water vapor.

  1. Water vapor in the lower stratosphere measured from aircraft flight

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.; Guenther, B.; Dunn, P.

    1976-01-01

    Water vapor in the lower stratosphere was measured in situ by two aluminum oxide hygrometers mounted on the nose of an RB57 aircraft. Data were taken nearly continuously from January to May 1974 from an altitude of approximately 11 km to 19 km as the aircraft flew between 70 deg N and 50 deg S over the land areas in the Western Hemisphere. Pseudomeridional cross sections of water vapor and temperature are derived from the flight data and show mixing ratios predominantly between 2 and 4 micron gm/gm with an extreme range of 1 to 8 micron gm/gm. Measurement precision is estimated by comparing the simultaneously measured values from the two flight hygrometer systems. Accuracy is estimated to be about + or - 40 percent at 19 km. A height-averaged latitudinal cross section of water vapor shows symmetry of wet and dry zones.

  2. Atmospheric Precorrected Differential Absorption technique to retrieve columnar water vapor

    SciTech Connect

    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

    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.

  3. Toward an operational water vapor remote sensing system using the global positioning system

    SciTech Connect

    Gutman, S.I.; Chadwick, R.B.; Wolf, d.W. [National Oceanic and Atmospheric Administration, Boulder, CO (United States); Simon, A. [Cooperative Institute for Research in Environmental Science, Boulder, CO (United States); Van Hove, T.; Rocken, C. [Univ. of Navstar Consortium, Boulder, CO (United States)

    1995-04-01

    Water vapor is one of the most important constituents of the free atmosphere since it is the principal mechanism by which moisture and latent heat are transported and cause weather. Recent experiments have demonstrated that data from Global Positioning System (GPS) satellites can be used to monitor precipitable water vapor (PWV) with millimeter accuracy and sub-hourly temporal resolution. Major advantages of GPS-based systems include the following: they work under virtually all weather conditions; individual systems do not have to be calibrated; and, they are relatively inexpensive.

  4. Diode laser absorption spectroscopy of water vapor in a scramjet combustor.

    PubMed

    Griffiths, Alan D; Houwing, A Frank P

    2005-11-01

    A sensor based on tunable diode laser absorption spectroscopy was constructed for time-resolved temperature and water vapor concentration measurements in a scramjet combustor. The sensor probed two absorption lines near 1390 nm with two time-multiplexed lasers used to measure temperature and water vapor concentration at up to 20 kHz. A demonstration experiment was performed in the supersonic, expanding exhaust region of the combustor, showing the measurement to be repeatable, able to resolve temporal trends during tunnel operation, and sensitive to changes in combustor operating conditions. PMID:16270554

  5. Ultrafast room-temperature crystallization of TiO2 nanotubes exploiting water-vapor treatment.

    PubMed

    Lamberti, Andrea; Chiodoni, Angelica; Shahzad, Nadia; Bianco, Stefano; Quaglio, Marzia; Pirri, Candido F

    2015-01-01

    In this manuscript a near-room temperature crystallization process of anodic nanotubes from amorphous TiO2 to anatase phase with a fast 30 minutes treatment is reported for the first time. This method involves the exposure of as-grown TiO2 nanotubes to water vapor flow in ambient atmosphere. The water vapor-crystallized samples are deeply investigated in order to gain a whole understanding of their structural, physical and chemical properties. The photocatalytic activity of the converted material is tested by dye degradation experiment and the obtained performance confirms the highly promising properties of this low-temperature processed material. PMID:25589038

  6. Advection-condensation paradigm for stratospheric water vapor

    NASA Astrophysics Data System (ADS)

    Liu, Y. S.; Fueglistaler, S.; Haynes, P. H.

    2010-12-01

    The advection-condensation (A-C) paradigm is a starting point for a theoretical framework for analysis of atmospheric water vapor distributions and changes therein in a changing climate. It postulates that water vapor concentrations are governed to leading order by the transport through the full four-dimensional temperature (and hence saturation mixing ratio) field. Brewer's (1949) qualitative deduction of the stratospheric circulation based on water vapor measurements was a first and prominently successful application of this paradigm. Here we examine the quantitative validity of the A-C paradigm by predicting stratospheric water vapor based on the saturation mixing ratio at the Lagrangian dry point of trajectories calculated using data from the European Centre for Medium-range Weather Forecasts. Using different data sets for the calculation, we show that results are sensitive to seemingly small differences in temperatures and wind fields and that interpretation of results (in terms of identification of effects of processes deliberately neglected by the advection-condensation paradigm) requires a careful error calculation. We introduce a semiempirical approach to analyze errors in the Lagrangian predictions of water vapor. We show that persistent (in time and space) errors in the temperature fields lead to similar errors in the Lagrangian model predictions. Conversely, biases in the variance of the temperature fields introduces a systematic bias in the model prediction. Further, model predictions are affected by dispersion and the time scale of troposphere-to-stratosphere transport. Our conclusion is that water vapor predictions for the stratospheric overworld based on the A-C paradigm have a dry bias of -40% ± 10% and -50% ± 10% when small-space-scale and short-time-scale temperature fluctuations not resolved by the ECMWF reanalyses are taken into account. We suggest that the correction to the A-C paradigm most likely to remove this dry bias is the inclusion of cloud microphysical processes (such as incomplete sedimentation of particles allowing reevaporation), which relax the assumption of instantaneous dehydration to the saturation mixing ratio. Interestingly, the bias attributed to the A-C paradigm in terms of water vapor concentration is found to be proportional to the measured water concentration, and a constant offset in terms of frost point temperature can account for much of the bias and its variability in water vapor mixing ratios.

  7. Water vapor measurements in- and outside cirrus with the novel water vapor mass spectrometer AIMS-H2O

    NASA Astrophysics Data System (ADS)

    Kaufmann, Stefan; Schlage, Romy; Voigt, Christiane; Jurkat, Tina; Krämer, Martina; Rolf, Christian; Zöger, Martin; Schäfler, Andreas; Dörnbrack, Andreas

    2015-04-01

    Water vapor plays a crucial role for the earth's climate both directly via its radiative properties and indirectly due to its ability to form clouds. However, accurate measurements of especially low water vapor concentrations prevalent in the upper troposphere and lower stratosphere are difficult and exhibit large discrepancies between different instruments and methods. In order to address this issue and to provide a comprehensive water vapor data set necessary to gather a complete picture of cloud formation processes, four state-of-the-art hygrometers including the novel water vapor mass spectrometer AIMS-H2O were deployed on the DLR research aircraft HALO during the ML-Cirrus campaign in March/April 2014 over Europe. Here, we present first water vapor measurements of AIMS-H2O on HALO. The instrument performance is validated by intercomparison with the fluorescence hygrometer FISH and the laser hygrometer SHARC, both also mounted in the aircraft. This intercomparison shows good agreement between the instruments from low stratospheric mixing ratios up to higher H2O concentrations at upper tropospheric conditions. Gathering data from over 24 flight hours, no significant offsets between the instruments were found (mean of relative deviation

  8. Water vapor spectroscopy in the 815-nm wavelength region for Differential Absorption Lidar measurements

    NASA Technical Reports Server (NTRS)

    Ponsardin, Patrick; Browell, Edward V.

    1995-01-01

    The differential absorption lidar (DIAL) technique was first applied to the remote measurement of atmospheric water vapor profiles from airborne platforms in 1981. The successful interpretation of the lidar profiles relies strongly on an accurate knowledge of specific water vapor absorption line parameters: line strength, pressure broadening coefficient, pressure-induced shift coefficient and the respective temperature-dependence factors. NASA Langley Research Center has developed and is currently testing an autonomous airborne water vapor lidar system: LASE (Lidar Atmospheric Sensing Experiment). This DIAL system uses a Nd:YAG-pumped Ti:Sapphire laser seeded by a diode laser as a lidar transmitter. The tunable diode has been selected to operate in the 813-818 nm wavelength region. This 5-nm spectral interval offers a large distribution of strengths for temperature-insensitive water vapor absorption lines. In support of the LASE project, a series of spectroscopic measurements were conducted for the 16 absorption lines that have been identified for use in the LASE measurements. Prior to this work, the experimental data for this water vapor absorption band were limited - to our knowledge - to the line strengths and to the line positions.

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

    PubMed

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

    2013-03-01

    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

  10. Dual-beam wavelength modulation spectroscopy for sensitive detection of water vapor

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Chang, Jun; Wei, Wei; Zhu, Cunguang; Tian, Changbin

    2014-12-01

    A technique was reported for sensitive detection of water vapor based on dual-beam wavelength modulation spectroscopy (WMS). Particular attention was focused on the problem of laser power variation (LPV) and residual amplitude modulation (RAM), which accounted for the absorption profile's distortion during application of WMS. Impact from LPV and RAM was eliminated by photocurrent normalization through a balanced ratiometric detector, which was a dual-beam technique with shot noise-level performance. When consideration of distortion was required, this could enormously simplify the spectra analysis procedure. In the experiment symmetry of the WMS, profile had gotten an improvement by a factor of about 102 compared with traditional single-beam method. During the application test of water vapor detection, the detected amplitude of WMS was well proportional to water vapor concentration ranging from 25 to 1,048 ppmv and the sensitivity was achieved to be 52 ppbv for just a 10-cm optical path length.

  11. Dual-beam wavelength modulation spectroscopy for sensitive detection of water vapor

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Chang, Jun; Wei, Wei; Zhu, Cunguang; Tian, Changbin

    2014-09-01

    A technique was reported for sensitive detection of water vapor based on dual-beam wavelength modulation spectroscopy (WMS). Particular attention was focused on the problem of laser power variation (LPV) and residual amplitude modulation (RAM), which accounted for the absorption profile's distortion during application of WMS. Impact from LPV and RAM was eliminated by photocurrent normalization through a balanced ratiometric detector, which was a dual-beam technique with shot noise-level performance. When consideration of distortion was required, this could enormously simplify the spectra analysis procedure. In the experiment symmetry of the WMS, profile had gotten an improvement by a factor of about 102 compared with traditional single-beam method. During the application test of water vapor detection, the detected amplitude of WMS was well proportional to water vapor concentration ranging from 25 to 1,048 ppmv and the sensitivity was achieved to be 52 ppbv for just a 10-cm optical path length.

  12. Stability of Materials in High Temperature Water Vapor: SOFC Applications

    NASA Technical Reports Server (NTRS)

    Opila, E. J.; Jacobson, N. S.

    2010-01-01

    Solid oxide fuel cell material systems require long term stability in environments containing high-temperature water vapor. Many materials in fuel cell systems react with high-temperature water vapor to form volatile hydroxides which can degrade cell performance. In this paper, experimental methods to characterize these volatility reactions including the transpiration technique, thermogravimetric analysis, and high pressure mass spectrometry are reviewed. Experimentally determined data for chromia, silica, and alumina volatility are presented. In addition, data from the literature for the stability of other materials important in fuel cell systems are reviewed. Finally, methods for predicting material recession due to volatilization reactions are described.

  13. Moisture burst structure in satellite water vapor imagery 

    E-print Network

    Ulsh, David Joel

    1988-01-01

    MOISTURE BURST STRUCTURE 1N SATELLITE WATER VAPOR IMAGERY A Thesis DAVID JOEL ULSH Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1988 Major... Subject: Meteorology MOISTURE BURST STRUCTURE IN SATELLITE WATER VAPOR IMAGERT A Thesis by DAVID JOEL ULSH Approved as to style and content by: James P. McGuzr)r (Co-Cha' an Aylrner H. Thompson (Co-Chairman) K th L. Whit (Member) James R. Sc...

  14. Airborne differential absorption lidar system for water vapor investigations

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Carter, A. F.; Wilkerson, T. D.

    1981-01-01

    Range-resolved water vapor measurements using the differential-absorption lidar (DIAL) technique is described in detail. The system uses two independently tunable optically pumped lasers operating in the near infrared with laser pulses of less than 100 microseconds separation, to minimize concentration errors caused by atmospheric scattering. Water vapor concentration profiles are calculated for each measurement by a minicomputer, in real time. The work is needed in the study of atmospheric motion and thermodynamics as well as in forestry and agriculture problems.

  15. Measurement of Water Vapor Sorption by Single Biological Aerosols

    Microsoft Academic Search

    Glenn O. Rubel

    1997-01-01

    Single particle levitation (SPL) is used to measure water vapor sorption and desorption from micrometer-sized particles comprised of Bacillus spores and yellow pine pollen. Water gain-loss is determined from increases-decreases in the weight-balancing levitation voltages. BET (Brunauer, Emmett, and Teller) surface area analysis of the spore water isotherms are performed and compared to values previously reported using bulk gravimetric methods.

  16. The Use of Additional GPS Frequencies to Independently Determine Tropospheric Water Vapor Profiles

    NASA Technical Reports Server (NTRS)

    Herman, B.M.; Feng, D.; Flittner, D. E.; Kursinski, E. R.

    2000-01-01

    It is well known that the currently employed L1 and L2 GPS/MET frequencies (1.2 - 1.6) Ghz) do not allow for the separation of water vapor and density (or temperature) from active microwave occultation measurements in regions of the troposphere warmer than 240 K Therefore, additional information must be used, from other types of measurements and weather analyses, to recover water vapor (and temperature) profiles. Thus in data sparse regions, these inferred profiles can be subject to larger errors than would result in data rich regions. The use of properly selected additional GPS frequencies enables a direct, independent measurement of the absorption associated with the water vapor profile, which may then be used in the standard GPS/MET retrievals to obtain a more accurate determination of atmospheric temperature throughout the water vapor layer. This study looks at the use of microwave crosslinks in the region of the 22 Ghz water vapor absorption line for this purpose. An added advantage of using 22 Ghz frequencies is that they are only negligibly affected by the ionosphere in contrast to the large effect at the GPS frequencies. The retrieval algorithm uses both amplitude and phase measurements to obtain profiles of atmospheric pressure, temperature and water water vapor pressure with a vertical resolution of 1 km or better. This technique also provides the cloud liquid water content along the ray path, which is in itself an important element in climate monitoring. Advantages of this method include the ability to make measurements in the presence of clouds and the use of techniques and technology proven through the GPS/MET experiment and several of NASA's planetary exploration missions. Simulations demonstrating this method will be presented for both clear and cloudy sky conditions.

  17. The effect of forced ventilation through snow on the stable water isotope content of the vapor and the snow - an experiment

    Microsoft Academic Search

    Sarah Berben; Hans Christian Steen-Larsen; Sigfus Johnsen

    2010-01-01

    The stable water isotope signal throughout an ice core is a well known and often used proxy for past temperature reconstructions and is important in our understanding of the climate system. The knowledge about the post depositional processes influencing the isotope signal within the snowpack is therefore important. As wind blow across the snow surface micro high and low pressure

  18. The isotopic composition of water vapor as a tracer of water balance in the TTL

    NASA Astrophysics Data System (ADS)

    Bolot, Maximilien; Moyer, Elisabeth; Legras, Bernard; Walker, Kaley; Boone, Chris; Bernath, Peter

    2015-04-01

    The relatively small amount of water vapor in the tropical tropopause layer (TTL) region is of disproportionate radiative importance, and projections of changes in TTL water are hampered by poor understanding of its sources and controls. We show here that the profile of the isotopic composition of water vapor can be used to quantify the contribution of various processes to the water budget of the region: convective sources of water, dehydration via in situ cirrus formation and sedimentation, and moistening from mixing with extratropical air. We combine these processes into a simple model for the isotopic ratio of TTL water vapor. By fitting the model parameters to reproduce an averaged tropical profile of water vapor isotopic ratio in the TTL, we can retrieve the convective contribution to TTL water vapor. Using isotopic measurements from the ACE-FTS solar-occultation instrument, we show that convective injection of water vapor must provide a significant contribution to TTL water vapor. That contribution in turn has large radiative effects, because it increases the production of in-situ cirrus over what would be inferred from large-scale uplift alone, by a factor 2-10 over the TTL (15-17.5 km).

  19. The seasonal variation of water vapor and ozone in the upper mesosphere - Implications for vertical transport and ozone photochemistry

    NASA Technical Reports Server (NTRS)

    Bevilacqua, Richard M.; Summers, Michael E.; Strobel, Darrell F.; Olivero, John J.; Allen, Mark

    1990-01-01

    This paper reviews the data base supplied by ground-based microwave measurements of water vapor in the mesosphere obtained in three separate experiments over an eight-year period. These measurements indicate that the seasonal variation of water vapor in the mesosphere is dominated by an annual component with low values in winter and high values in summer, suggesting that the seasonal variation of water vapor in the mesosphere (below 80 km) is controlled by advective rather than diffusive processes. Both the seasonal variation and the absolute magnitude of the water vapor mixing ratios obtained in microwave measurements were corroborated by measurements obtained in the Spacelab GRILLE and ATMOS experiments, and were found to be consistent with several recent mesospheric dynamics studies.

  20. Deuterium excess reveals diurnal sources of water vapor in forest air (Invited)

    Microsoft Academic Search

    C. Lai

    2010-01-01

    An understanding of atmospheric water vapor content and its isotopic composition is important if we are to be able to model future water vapor dynamics and its potential feedbacks on future climate change. Here I present diurnal and vertical patterns of water isotope ratios in forest air (delta2Hv and delta18Ov) not observed previously. Water vapor observed at 3 heights over

  1. Water vapor plasma technology for biomass conversion to synthetic gas

    Microsoft Academic Search

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

    2011-01-01

    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

  2. Water vapor pressure versus environmental lapse rate near the tropopause

    NASA Astrophysics Data System (ADS)

    Ferreira, Antonio; Castanheira, Jose; Gimeno, Luis

    2010-05-01

    The relationship between water vapor pressure and temperature lapse rate in the vicinity of the tropopause was investigated using in situ observations. The water vapor partial pressures and the lapse rates within a vertical distance of ±1.5 km around the first thermal tropopause were calculated from the vertical soundings conducted by the NOAA/CMDL at several locations in the last few decades (GMD Data Archive). A positive non-linear relationship between the two quantities was found to hold across the studied tropopause region at mid-latitudes and polar latitudes. A similar analysis was performed on the 300 and 250 hPa pressure levels (which often intercept the tropopause region), by collecting temperature and humidity observations within 1979-2008 from the Integrated Global Radiosonde Archive (IGRA). A relationship having almost the same shape was detected for statically stable lapse rates at all latitude zones. Given the relevance of water vapor in the radiative transfer in the upper troposphere, the results are an indication of a local influence of water vapor on the thermal structure of the transition layer between the troposphere and stratosphere

  3. Condensation of water vapor in rarefaction waves. I - Homogeneous nucleation

    Microsoft Academic Search

    J. P. Sislian; I. I. Glass

    1976-01-01

    A detailed theoretical investigation has been made of the condensation of water vapor\\/carrier gas mixtures in the nonstationary rarefaction wave generated in a shock tube. It is assumed that condensation takes place by homogeneous nucleation. The equations of motion together with the nucleation rate and the droplet growth equations were solved numerically by the method of characteristics and Lax's method

  4. Tropospheric water vapor measurements with an airborne lidar system

    NASA Technical Reports Server (NTRS)

    Browell, E. V.; Higdon, N. S.; Butler, C. F.; Fenn, M. A.; Grossmann, B. E.; Ponsardin, P.; Grant, W. B.; Bachmeier, A. S.

    1991-01-01

    A differential absorption lidar system has been developed for the remote measurement of atmospheric water vapor and aerosol distributions from an aircraft. The first extensive observations of H2O and aerosols in the lower troposphere made with this system are briefly discussed.

  5. High-resolution terahertz atmospheric water vapor continuum measurements

    NASA Astrophysics Data System (ADS)

    Slocum, David M.; Goyette, Thomas M.; Giles, Robert H.

    2014-05-01

    The terahertz frequency regime is often used as the `chemical fingerprint' region of the electromagnetic spectrum due to the large number of rotational and vibrational transitions of many molecules of interest. This region of the spectrum has particular utility for applications such as pollution monitoring and the detection of energetic chemicals using remote sensing over long path lengths through the atmosphere. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across a wide spectrum are lacking. The water vapor continuum absorption is an excess absorption that is unaccounted for in resonant line spectrum simulations. Currently a semiempirical model is employed to account for this absorption, however more measurements are necessary to properly describe the continuum absorption in this region. Fourier Transform Spectroscopy measurements from previous work are enhanced with high-resolution broadband measurements in the atmospheric transmission window at 1.5THz. The transmission of broadband terahertz radiation through pure water vapor as well as air with varying relative humidity levels was recorded for multiple path lengths. The pure water vapor measurements provide accurate determination of the line broadening parameters and experimental measurements of the transition strengths of the lines in the frequency region. Also these measurements coupled with the atmospheric air measurements allow the water vapor continuum absorption to be independently identified at 1.5THz. Simulations from an atmospheric absorption model using parameters from the HITRAN database are compared with the current and previous experimental results.

  6. Water-Vapor Raman Lidar System Reaches Higher Altitude

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, I. Stewart

    2010-01-01

    A Raman lidar system for measuring the vertical distribution of water vapor in the atmosphere is located at the Table Mountain Facility (TMF) in California. Raman lidar systems for obtaining vertical water-vapor profiles in the troposphere have been in use for some time. The TMF system incorporates a number of improvements over prior such systems that enable extension of the altitude range of measurements through the tropopause into the lower stratosphere. One major obstacle to extension of the altitude range is the fact that the mixing ratio of water vapor in the tropopause and the lower stratosphere is so low that Raman lidar measurements in this region are limited by noise. Therefore, the design of the TMF system incorporates several features intended to maximize the signal-to-noise ratio. These features include (1) the use of 355-nm-wavelength laser pulses having an energy (0.9 J per pulse) that is high relative to the laser-pulse energy levels of prior such systems, (2) a telescope having a large aperture (91 cm in diameter) and a narrow field of view (angular width .0.6 mrad), and (3) narrow-bandpass (wavelength bandwidth 0.6 nm) filters for the water-vapor Raman spectral channels. In addition to the large-aperture telescope, three telescopes having apertures 7.5 cm in diameter are used to collect returns from low altitudes.

  7. Time domain measurement of the THz refractivity of water vapor

    E-print Network

    Oklahoma State University

    . Abou-Zeid, "High-accuracy determination of water vapor refractivity by length interferometry," Opt. Delitsky, J. C. Pearson, and H. S. P. Muller, "Sub-millimeter, millimeter, and microwave spectral line, Microwave Spectroscopy (Dover Publ. Co., 1975). 20. M. van Exter and D. Grischkowsky, "Optical

  8. Oxidation and Volatilization of Silica-Formers in Water Vapor

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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

  9. Advanced Detector and Waveform Digitizer for Water Vapor DIAL Systems

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    Measurement of atmospheric water vapor has become a major requirement for understanding moist-air processes. Differential absorption lidar (DIAL) is a technique best suited for the measurement of atmospheric water vapor. NASA Langley Research Center is continually developing improved DIAL systems. One aspect of current development is focused on the enhancement of a DIAL receiver by applying state-of-the-art technology in building a new compact detection system that will be placed directly on the DIAL receiver telescope. The newly developed detection system has the capability of being digitally interfaced with a simple personal computer, using a discrete input/output interface. This has the potential of transmitting digital data over relatively long distances instead of analog signals, which greatly reduces measurement noise. In this paper, we discuss some results from the new compact water vapor DIAL detection system which includes a silicon based avalanche photodiode (APD) detector, a 14-bit, 10-MHz waveform digitizer, a microcontroller and other auxiliary electronics. All of which are contained on a small printed-circuit-board. This will significantly reduce the weight and volume over the current CAMAC system and eventually will be used in a water vapor DIAL system on an unpiloted atmospheric vehicle (UAV) aircraft, or alternatively on an orbiting spacecraft.

  10. Variations in water vapor continuum radiative transfer with atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Paynter, D.; Ramaswamy, V.

    2012-08-01

    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.

  11. Columnar water vapor retrievals from multifilter rotating shadowband radiometer data

    E-print Network

    (MFRSR) measures direct and diffuse irradiances in the visible and near-infrared spectral range data for creation of 2D data sets comparable with that of the MODIS satellite water vapor product (MODIS [Kaufman et al., 1997]) on NASA Aqua and Terra platforms, the Atmo- spheric Infrared Sounder (AIRS

  12. DMSP SSM\\/T-2 microwave water vapor profiler

    Microsoft Academic Search

    Israel Galin; Dennis H. Brest; Glen R. Martner

    1993-01-01

    The Special Sensor Microwave water vapor profiler (SSM\\/T-2) is a five channel passive microwave sensor that operates in the 90 - 190 GHz frequency band. The instrument was developed by Aerojet Electronic Systems Division (AESD) of GenCorp Aerojet under a contract to the Defense Meteorological Satellite Program (DMSP). The first in a series of these instruments was successfully orbited in

  13. A climatological data base of arctic water vapor characteristics

    Microsoft Academic Search

    M. C. Serreze; M. C. Rehder; R. G. Barry; J. D. Kahl

    1994-01-01

    Using a blend of rawinsonde ascents from fixed stations, ships, and Russian drifting ice stations, a gridded climatological monthly?mean data base of Arctic water vapor characteristics is assembled that is suitable for use as input and validation data for simulations of Arctic climate from general circulation models. Preparation of the data base is described and examples of selected data fields

  14. 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...

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

    SciTech Connect

    Westwater, Edgeworth

    2011-05-06

    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.

  16. Water vapor sorption in naphthalenic sulfonated polyimide membranes

    Microsoft Academic Search

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

    2001-01-01

    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

  17. The reaction kinetics of lithium salt with water vapor

    Microsoft Academic Search

    M. Balooch; L. N. Dinh; D. F. Calef

    2002-01-01

    The interaction of lithium salt (LiH and\\/or LiD) with water vapor in the partial pressure range of 10?5–2657 Pa has been investigated. The reaction probability of water with LiH cleaved in an ultra high vacuum environment was obtained using the modulated molecular beam technique. This probability was 0.11 and independent of LiH surface temperature, suggesting a negligible activation energy for

  18. Fixation of nitrogen in the presence of water vapor

    DOEpatents

    Harteck, Paul (Santa Barbara, CA)

    1984-01-01

    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.

  19. Columnar water vapor retrievals from multifilter rotating shadowband radiometer data

    SciTech Connect

    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

    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.

  20. Alexandrite laser transmitter development for airborne water vapor DIAL measurements

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

  1. Columnar water vapor retrievals from multifilter rotating shadowband radiometer data

    NASA Astrophysics Data System (ADS)

    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

    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.

  2. A far-infrared radiative closure study in the Arctic: Application to water vapor

    NASA Astrophysics Data System (ADS)

    Delamere, J. S.; Clough, S. A.; Payne, V. H.; Mlawer, E. J.; Turner, D. D.; Gamache, R. R.

    2010-09-01

    Far-infrared (? > 15.0 ?m) (far-IR) radiative processes provide a large fraction of Earth's outgoing longwave radiation and influence upper tropospheric vertical motion. Water vapor, because of its abundance and strong absorption properties over an extended spectral range, is the primary source of these radiative processes. Historically, the lack of spectrally resolved radiometric instruments and the opacity of the lower atmosphere have precluded extensive studies of far-IR water vapor absorption properties. The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program has organized a series of field experiments, the Radiative Heating in Underexplored Bands Campaigns (RHUBC), to address this deficiency. The first phase of RHUBC took place in 2007 at the ARM North Slope of Alaska Climate Research Facility. Measurements taken before and during this campaign have provided the basis for a clear-sky radiative closure study aimed at reducing key uncertainties associated with far-IR radiative transfer models. Extended-range Atmospheric Emitted Radiance Interferometer infrared radiance observations taken in clear sky conditions were compared against calculations from the Line-By-Line Radiative Transfer Model. The water vapor column amounts used in these calculations were retrieved from 183 GHz radiometer measurements. The uncertainty in these integrated water vapor retrievals is approximately 2%, a notable improvement over past studies. This far-IR radiative closure study resulted in an improvement to the Mlawer-Tobin Clough-Kneiyzs-Davies (MT_CKD) water vapor foreign continuum model and updates to numerous, far-IR water vapor line parameters from their values in the circa 2006 version of the HITRAN molecular line parameter database.

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

    SciTech Connect

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

    2011-07-06

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  5. Tm:germanate Fiber Laser for Planetary Water Vapor Atmospheric Profiling

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; De Young, Russell

    2009-01-01

    The atmospheric profiling of water vapor is necessary for finding life on Mars and weather on Earth. The design and performance of a water vapor lidar based on a Tm:germanate fiber laser is presented.

  6. A model for the relationship between tropical precipitation and column water vapor

    E-print Network

    Muller, Caroline

    Several observational studies have shown a tight relationship between tropical precipitation and column-integrated water vapor. We show that the observed relationship in the tropics between column-integrated water vapor, ...

  7. The roles of aerosol, water vapor and cloud in future global dimming\\/brightening

    Microsoft Academic Search

    Jim M. Haywood; Nicolas Bellouin; Andy Jones; Olivier Boucher; Martin Wild; Keith P. Shine

    2011-01-01

    HADGEM2-ES climate simulations represent global dimming and brightening trendsFuture scenarios suggest increases in water vapor of up to 35% by 2090Water vapor increases cause widespread global dimming in cloud-free fluxes

  8. Deuterium excess reveals diurnal sources of water vapor in forest air (Invited)

    NASA Astrophysics Data System (ADS)

    Lai, C.

    2010-12-01

    An understanding of atmospheric water vapor content and its isotopic composition is important if we are to be able to model future water vapor dynamics and its potential feedbacks on future climate change. Here I present diurnal and vertical patterns of water isotope ratios in forest air (?2Hv and ?18Ov) not observed previously. Water vapor observed at 3 heights over 3 consecutive days in a coniferous forest in the Pacific Northwest, USA, shows a stratified nocturnal structure of ?2Hv and ?18Ov, with the most positive values consistently observed above the canopy (60 m). Differences between 0.5m and 60m range between 2-6‰ for ?18O and 20-40‰ for ?2H at night. Using a box model, we simulated H2O isotope fluxes and showed that the low to high ?2Hv and ?18Ov profiles can be explained by the vapor flux associated with evaporation from the forest floor and canopy transpiration. We used d-excess as a diagnostic tracer to identify processes that contribute to the diurnal variation in atmospheric moisture. Values of d-excess derived from water vapor measurements showed a repeated diel pattern with the lowest values occurring in the early morning and the highest values occurring at midday. The isotopic composition of rain water, collected during a light rain event in the first morning of our experiment, suggested that considerable below-cloud secondary evaporation occurred during the descent of raindrops. We conclude that atmospheric entrainment appears to drive the isotopic variation of water vapor in the early morning when the convective boundary layer rapidly develops, while evapotranspiration becomes more important in the mid-afternoon as a primary moisture source of water vapor in this forest. Our results demonstrate the interplay between the effects of vegetation and boundary layer mixing under the influence of rain evaporation, which has implications to larger-scale predictions of precipitation across the terrestrial landscape. Variation in d-excess derived from observed and modeled water vapor isotope ratios within and above an old-growth coniferous forest in Wind River Canopy Crane Research Forest, WA, USA.

  9. A SEARCH FOR WATER VAPORIZATION ON CERES

    SciTech Connect

    Rousselot, P.; Mousis, O.; Zucconi, J.-M. [Observatoire de Besancon, Institut UTINAM-UMR CNRS 6213, University of Franche-Comte, BP 1615, 25010 Besancon Cedex (France); Jehin, E.; Manfroid, J. [Institut d'Astrophysique et de Geophysique, Universite de Liege, Allee du 6 aout 17, B-4000 Liege (Belgium); Dumas, C. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19 (Chile); Carry, B. [European Space Astronomy Centre, ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid (Spain); Marboeuf, U., E-mail: rousselot@obs-besancon.fr [Institut de Planetologie et d'Astrophysique de Grenoble, Universite Joseph Fourier, CNRS INSU (France)

    2011-10-15

    There are hints that the dwarf planet (1) Ceres may contain a large amount of water ice. Some models and previous observations suggest that ice could be close enough to the surface to create a flux of water outward through the regolith. This work aims to confirm a previous detection of OH emission off the northern limb of Ceres with the International Ultraviolet Explorer (IUE). Such emission would be evidence of water molecules escaping from the dwarf planet. We used the Ultraviolet and Visual Echelle Spectrograph of the Very Large Telescope to obtain spectra off the northern and southern limbs of Ceres at several epochs. These spectra cover the 307-312 nm wavelength range corresponding to the OH (0,0) emission band, which is the brightest band of this radical, well known in the cometary spectra. These new observations, five times more sensitive than those from IUE, did not permit detection of OH around Ceres. We derive an upper limit for the water production of about {approx}7 x 10{sup 25} molecules s{sup -1} and estimate the minimum thickness of the dust surface layer above the water ice layer (if present) to be about 20 m.

  10. Preliminary Design Program: Vapor Compression Distillation Flight Experiment Program

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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.

  11. Alumina Volatility in Water Vapor at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Myers, Dwight L.

    2003-01-01

    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.

  12. Absorptivity of water vapor for 10.6 micron radiation

    NASA Technical Reports Server (NTRS)

    Pugh, E. R.; Krech, R. H.

    1982-01-01

    Attention is called to recent measurements of the absorptivity of water vapor to 10.6-micron laser radiation made using shock-heated H2O/H2 and H2O/Ar mixtures and a probe CO2 laser. It is noted that these measurements give values about a factor of 2 lower than Ludwig's (1971) low resolution values. It is also argued that Fowler's (1981) high values are not likely to be caused by excited water molecules. It is shown that very intense laser radiation would be required to obtain any appreciable vibrational nonequilibrium. Within the narrow spectral range of 944-948/cm, no significant variation in absorption coefficient (suitably normalized) is observed as a function of laser line, water vapor concentration, total pressure, or diluent gas.

  13. CRISM Limb Observations of Aerosols and Water Vapor

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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.

  14. Remote Sensing of Atmospheric Water Vapor with the Global Positioning System

    E-print Network

    Remote Sensing of Atmospheric Water Vapor with the Global Positioning System A Dissertation John: Remote Sensing of Atmospheric Water Vapor with the Global Positioning System Written by John Joseph Braun Water Vapor with the Global Positioning System Thesis directed by Professor Judith Curry Signals from

  15. Retrieval Of Atmospheric Water Vapor Profiles Using Radiometric Measurements At 183 GHz And 90 GHz

    Microsoft Academic Search

    R. Lutz; T. T. Wilheit; J. R. Wang; R. K. Kakar

    1990-01-01

    Some algorithms utilizing the strong 183.3 GHz water vapor absorption line have been developed for the retrieval of atmospheric water vapor profiles in the past decade [l-61. The one developed by Wilheit [6] dealt with the retrieval of water vapor profiles from the microwave radiometric measurements even in the presence of clouds. This algorithm was tested with the radiometric measurements

  16. Correlation for the Vapor Pressure of Heavy Water From the Triple Point to the Critical Point

    E-print Network

    Magee, Joseph W.

    Correlation for the Vapor Pressure of Heavy Water From the Triple Point to the Critical Point Allan the vapor pressure of heavy water (D2O) from its triple point to its critical point. This work takes and ordinary water,2­4 a determination of the vapor pressure of D2O at its triple point,5 and the adoption

  17. Simultaneous ground-based remote sensing of water vapor by differential absorption and Raman lidars

    Microsoft Academic Search

    D. D. Turner; H. Linne; J. Bosenberg; S. Lehmann; K. Ertel; J. E. M. Goldsmith; T. P. Tooman

    2000-01-01

    Uncertainties in the absolute calibration of the water vapor measurements are currently the limiting factor in the improvement of radiative transfer algorithms for clear skies. While instruments such as the microwave radiometer can provide accurate measurements of total precipitable water vapor in the column, accurate profiles of water vapor are also needed in order to calculate accurate cooling rate profiles.

  18. Remote sensing of water vapor in the near IR from EOS\\/MODIS

    Microsoft Academic Search

    Yoram J. Kaufman; Bo-Cai Gao

    1992-01-01

    The LOWTRAN-7 code was used to simulate remote sensing of water vapor over 20 different surface covers. The simulation was used to optimize the water vapor channel selection and to test the accuracy of the remote sensing method. The channel selection minimizes the uncertainty in the derived water vapor due to variations in the spectral dependence of the surface reflectance.

  19. Water vapor transport and dehydration above convective outflow during Asian monsoon

    E-print Network

    Legras, Bernard

    Water vapor transport and dehydration above convective outflow during Asian monsoon R. James,1 M-scale transport and convection in determining the water vapor maximum at 100 hPa in the Asian monsoon region of overshoots. A good agreement between reconstructed water vapor and observations is obtained over Asia

  20. A farinfrared radiative closure study in the Arctic: Application to water vapor

    E-print Network

    Gamache, Robert R.

    A farinfrared radiative closure study in the Arctic: Application to water vapor J. S. Delamere,1 S and influence upper tropospheric vertical motion. Water vapor, because of its abundance and strong absorption precluded extensive studies of farIR water vapor absorption properties. The U.S. Department of Energy

  1. Summary Weusedthreemethodstomeasureboundarylayer conductance to heat transfer (gbH) and water vapor transfer

    E-print Network

    Martin, Timothy

    Summary Weusedthreemethodstomeasureboundarylayer conductance to heat transfer (gbH) and water vapor (rsV) measured with a porometer from the total branch vapor phase resistance were unusually small, water vapor transfer. Introduction Water loss from plant leaves is controlled by boundary layer

  2. Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations

    E-print Network

    Sun, Dezheng

    1 Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled to J. Climate #12;2 ABSTRACT: By comparing the response of clouds and water vapor to ENSO forcing cloud and water vapor feedbacks has revealed two common biases in the models: (1) an underestimate

  3. Water Vapor Transport and the Production of Precipitation in the Eastern Fertile Crescent

    E-print Network

    Evans, Jason

    Water Vapor Transport and the Production of Precipitation in the Eastern Fertile Crescent J. P to quantify the significance of southerly water vapor fluxes on precipitation occurring in the eastern Fertile Crescent region. The water vapor fluxes were investigated at high temporal and spatial resolution by using

  4. SURFACE WATER VAPOR EXCHANGES ON THE GREENLAND ICE SHEET DERIVED FROM AUTOMATED WEATHER STATION DATA

    E-print Network

    Box, Jason E.

    1 SURFACE WATER VAPOR EXCHANGES ON THE GREENLAND ICE SHEET DERIVED FROM AUTOMATED WEATHER STATION.D. Geography) Surface Water Vapor Exchanges on the Greenland Ice Sheet Derived From Automated Weather Station observations are used to estimate surface water vapor exchanges at Greenland ice sheet sites and for the ice

  5. In situ water vapor and ozone measurements in Lhasa and Kunming during the Asian summer monsoon

    E-print Network

    Pan, Laura

    In situ water vapor and ozone measurements in Lhasa and Kunming during the Asian summer monsoon for water vapor and pollutants to enter the stratosphere. The observational evidence, however, is largely based on satellite retrievals. We report the first coincident in situ measurements of water vapor

  6. Water vapor and precipitation isotope ratios in Beijing, China Xue-Fa Wen,1

    E-print Network

    Lee, Xuhui

    Water vapor and precipitation isotope ratios in Beijing, China Xue-Fa Wen,1 Shi-Chun Zhang,1 Xiao the characteristics of dD, d18 O, and deuterium excess (d) of precipitation and water vapor in surface air in Beijing, China. The dD, d18 O, and d of atmospheric water vapor in surface air were measured continuously

  7. Intercomparison of stratospheric water vapor profiles obtained during the Balloon Intercomparison Campaign

    Microsoft Academic Search

    D. Murcray; A. Goldman; J. Kosters; R. Zander; W. Evans; N. Louisnard; C. Alamichel; M. Bangham; S. Pollitt; B. Carli; B. Dinelli; S. Piccioli; A. Volboni; W. Traub; K. Chance

    1990-01-01

    The Balloon Intercomparison Campaign (BIC) was set up to intercompare remote sensing measurements of a number of compounds other than water vapor; however, water vapor has strong absorption features throughout the infrared and mm wave regions of the spectrum. Therefore many of the investigators involved in BIC have absorption or emission features due to water vapor in the data they

  8. Stable Calibration of Raman Lidar Water-Vapor Measurements

    NASA Technical Reports Server (NTRS)

    Leblanc, Thierry; McDermid, Iain S.

    2008-01-01

    A method has been devised to ensure stable, long-term calibration of Raman lidar measurements that are used to determine the altitude-dependent mixing ratio of water vapor in the upper troposphere and lower stratosphere. Because the lidar measurements yield a quantity proportional to the mixing ratio, rather than the mixing ratio itself, calibration is necessary to obtain the factor of proportionality. The present method involves the use of calibration data from two sources: (1) absolute calibration data from in situ radiosonde measurements made during occasional campaigns and (2) partial calibration data obtained by use, on a regular schedule, of a lamp that emits in a known spectrum determined in laboratory calibration measurements. In this method, data from the first radiosonde campaign are used to calculate a campaign-averaged absolute lidar calibration factor (t(sub 1)) and the corresponding campaign-averaged ration (L(sub 1)) between lamp irradiances at the water-vapor and nitrogen wavelengths. Depending on the scenario considered, this ratio can be assumed to be either constant over a long time (L=L(sub 1)) or drifting slowly with time. The absolutely calibrated water-vapor mixing ratio (q) obtained from the ith routine off-campaign lidar measurement is given by q(sub 1)=P(sub 1)/t(sub 1)=LP(sub 1)/P(sup prime)(sub 1) where P(sub 1) is water-vapor/nitrogen measurement signal ration, t(sub 1) is the unknown and unneeded overall efficiency ratio of the lidar receiver during the ith routine off-campaign measurement run, and P(sup prime)(sub 1) is the water-vapor/nitrogen signal ratio obtained during the lamp run associated with the ith routine off-campaign measurement run. If L is assumed constant, then the lidar calibration is routinely obtained without the need for new radiosonde data. In this case, one uses L=L(sub 1) = P(sup prime)(sub 1)/t(sub 1), where P(sub 1)(sup prime) is the water-vapor/nitrogen signal ratio obtained during the lamp run associated with the first radiosonde campaign. If L is assumed to drift slowly, then it is necessary to postpone calculation of a(sub 1) until after a second radiosonde campaign. In this case, one obtains a new value, L(sub 2), from the second radiosonde campaign, and for the ith routine off-campaign measurement run, one uses an intermediate value of L obtained by simple linear time interpolation between L(sub 1) and L(sub 2).

  9. Water Mist Experiment

    NASA Technical Reports Server (NTRS)

    2001-01-01

    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.

  10. Self-deactivation of water vapor - Role of the dimer

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1984-01-01

    A phenomenological multiple-relaxation theory of the deactivation rate constant for the nu-2 (1 - 0) bending mode of water vapor is presented which incorporates the role not only of the excited monomer but also of the bound molecular complex, in particular the dimer. The deactivation takes place by means of three parallel processes: (1) collisional deexcitation of the excited monomer, (2) a two-step reaction involving association and spontaneous redissociation of an H2O collision complex, and (3) spontaneous dissociation of the stably bound H2O dimer. Oxygen, but not nitrogen or argon, serves as an effective chaperon for the formation of the activated complex. This observation explains the impurity dependence of the self-deactivation rate constant of water vapor. Analysis of an ultrasonic absorption peak based on the third process yields values for the standard entropy and enthalpy of dissociation of the stably bound H2O dimer.

  11. Relating A-Train Water Vapor Observations to Cloud Classes from CloudSat

    NASA Astrophysics Data System (ADS)

    Fetzer, E. J.; Kahn, B. H.; Teixeira, J.; Fishbein, E. F.; Wilson, B. D.; Waliser, D. E.

    2008-12-01

    Three of the standard data sets from the NASA A-Train satellite constellation are CloudSat cloud classes, Atmospheric Infrared Sounder (AIRS) moist thermodynamic observations, and Advanced Microwave Sounding Radiometer for EOS (AMSR-E) total precipitable water vapor. We describe AIRS and AMSR-E water vapor observability, and the associated climatologies, conditional on CloudSat cloud classes. Because cloud classes represent unique physical processes, each scene type can be expected to have distinct temperature and water vapor signatures. Understanding the sampling characteristics of the water vapor observations is critical to interpreting them in the context of changing cloud and water vapor regimes.

  12. Sensing integrated water vapor along GPS ray paths

    Microsoft Academic Search

    Randolph Ware; Chris Alber; Christian Rocken; Fredrick Solheim

    1997-01-01

    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

  13. Extratropical influence of upper tropospheric water vapor on Greenhouse warming

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Hu, Hua

    1997-01-01

    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).

  14. Mass Spectrometry of Ions in Glow Discharges. IV. Water Vapor

    Microsoft Academic Search

    P. F. KNEWSTUBBt; A. W. Tickner

    1963-01-01

    Ions from the negative glow and Faraday dark space of discharges in water vapor have been analyzed with a mass spectrometer. The ions observed are of the form H3O+·(H2O)n with n=0 to 5. It is shown that the observations are altered by the sampling process to an extent which depends on discharge conditions and is sometimes quite large. This effect

  15. Sputtering iron oxide films by a water vapor process

    Microsoft Academic Search

    Zeng-Jun Zhou; Jun-Jue Yan

    1992-01-01

    The magnetic properties and structure of Fe3O4 thin films under different preparation conditions have been evaluated. The main deposition parameter in this study was the ratio of water vapor partial pressure to argon partial pressure. TEM images showed that the surface structures are homogeneous for the different preparation conditions. STM study offered in more detail three-dimensional surface patterns. Temperature dependence

  16. Water vapor retrieval using the FLAASH atmospheric correction algorithm

    Microsoft Academic Search

    Gerald W. Felde; Gail P. Anderson; James A. Gardner; Steven M. Adler-Golden; Michael W. Matthew; Alexander Berk

    2004-01-01

    FLAASH (Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes) is a first-principles atmospheric correction algorithm for visible to shortwave infrared (SWIR) hyperspectral data. The algorithm consists of two main steps. The first is retrieval of atmospheric parameters, visibility (which is related to the aerosol type and distribution) and column water vapor. The second step is solving the radiation transport equation for

  17. Vapor-deposited water and nitric acid ices

    NASA Astrophysics Data System (ADS)

    Leu, Ming-Taun; Keyser, Leon F.

    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.

  18. Deuterium excess reveals diurnal sources of water vapor in forest air.

    PubMed

    Lai, Chun-Ta; Ehleringer, James R

    2011-01-01

    An understanding of atmospheric water vapor content and its isotopic composition is important if we are to be able to model future water vapor dynamics and their potential feedback on future climate change. Here we present diurnal and vertical patterns of water isotope ratios in forest air (?(2)H(v) and ?(18)O(v)) not observed previously. Water vapor observed at three heights over 3 consecutive days in a coniferous forest in the Pacific Northwest of the United States, shows a stratified nocturnal structure of ?(2)H(v) and ?(18)O(v), with the most positive values consistently observed above the canopy (60 m). Differences between 0.5 m and 60 m range between 2-6‰ for ?(18)O and 20-40‰ for ?(2)H at night. Using a box model, we simulated H(2)O isotope fluxes and showed that the low to high ?(2)H(v) and ?(18)O(v) profiles can be explained by the vapor flux associated with evaporation from the forest floor and canopy transpiration. We used d-excess as a diagnostic tracer to identify processes that contribute to the diurnal variation in atmospheric moisture. Values of d-excess derived from water vapor measurements showed a repeated diel pattern, with the lowest values occurring in the early morning and the highest values occurring at midday. The isotopic composition of rain water, collected during a light rain event in the first morning of our experiment, suggested that considerable below-cloud secondary evaporation occurred during the descent of raindrops. We conclude that atmospheric entrainment appears to drive the isotopic variation of water vapor in the early morning when the convective boundary layer rapidly develops, while evapotranspiration becomes more important in the mid-afternoon as a primary moisture source of water vapor in this forest. Our results demonstrate the interplay between the effects of vegetation and boundary layer mixing under the influence of rain evaporation, which has implications for larger-scale predictions of precipitation across the terrestrial landscape. PMID:20652594

  19. Molecular dynamics of the water liquid-vapor interface

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  20. Characteristics of Water Vapor Under Partially Cloudy Conditions: Observations by the Atmospheric Infrared Sounder (AIRS)

    NASA Astrophysics Data System (ADS)

    Fishbein, E.

    2003-12-01

    The variability and quality of tropical water vapor derived from the Atmospheric Infrared Sounder (AIRS) are characterized. Profiles of water vapor, temperature and surface characteristics (states) are derived from coincident Advance Microwave Sounding Unit (AMSU) and 3x3 sets of AIRS footprints. States are obtained under partially cloudy conditions by estimating the radiances emitted from the clear portions of the AIRS footprints. This procedure, referred to as cloud clearing, amplifies the measurement noise, and the amplification increases with cloud amount and uniformity. Cumulus and stratus cloud amount are related to the water vapor saturation, and noise amplification and water vapor amount may be partially correlated. The correlations between the uncertainty of retrieved water vapor, cloudiness and noise amplification are characterized. Retrieved water vapor is generally good when the amplification is less than three. Water vapor profiles are compared with correlative data, such as radiosondes and numerical weather center analyses and are in relatively good agreement in the lower troposphere

  1. Shock-induced vaporization of zinc -- Experiments and numerical simulations

    Microsoft Academic Search

    L. C. Chhabildas; R. M. Brannon

    1996-01-01

    Prediction of the interaction between expanded vaporized debris and target materials for applications such as meteorite impact on space vehicles, ballistic penetration of armors, debris shield design, etc. demands an accurate treatment of the melting and vaporization process and the kinetics of liquid-vapor propagation. Historically, experimental efforts to understand high-pressure melting and vaporization have been hindered by unavailability of experimental

  2. Retrieval of Clear Sky Moisture Profiles using the 183 GHz Water Vapor Line

    Microsoft Academic Search

    Ramesh K. Kakar

    1983-01-01

    A technique for retrieving vertical moisture profiles from downlooking radiometric measurements of atmospheric radiation near the 183 GHz water vapor line is described. A simulation experiment utilizing this retrieval technique and temperature and moisture profiles from tropical radiosonde stations has been carried out. Assuming the atmospheric temperature profile is known to 2K rms (state-of-the-art with present remote sensors) and the

  3. Water vapor stable isotope observations from tropical Australia

    NASA Astrophysics Data System (ADS)

    Parkes, Stephen; Deutscher, Nicholas; Griffith, David; McCabe, Matthew

    2015-04-01

    The response of the tropical hydrological cycle to anthropogenically induced changes in radiative forcing is one of the largest discrepancies between climate models. Paleoclimate archives of the stable isotopic composition of precipitation in the tropics indicate a relationship with precipitation amount that could be exploited to study past hydroclimate and improve our knowledge of how this region responds to changes in climate forcing. Recently modelling studies of convective parameterizations fitted with water isotopes and remote sensing of water vapor isotopes in the tropics have illustrated uncertainty in the assumed relationship with rainfall amount. Therefore there is a need to collect water isotope data in the tropics that can be used to evaluate these models and help identify the relationships between the isotopic composition of meteoric waters and rainfall intensity. However, data in this region is almost non-existent. Here we present in-situ water vapor isotopic measurements and the HDO retrievals from the co-located Total Column Carbon Observing Network (TCCON) site at Darwin in Tropical Australia. The Darwin site is interestingly placed within the tropical western pacific region and is impacted upon by a clear monsoonal climate, and key climate cycles including ENSO and Madden Julian Oscillations. The analysis of the data illustrated relationships between water vapor isotopes and humidity which demonstrated the role of precipitation processes in the wet season and air mass mixing during the dry season. Further the wet season observations show complex relationships between humidity and isotopes. A simple Rayleigh distillation model was not obeyed, instead the importance of rainfall re-evaporation in generating the highly depleted signatures was demonstrated. These data potentially provide a useful tool for evaluating model parameterizations in monsoonal regions as they demonstrate relationships with precipitation processes that cannot be observed with more traditional observations.

  4. Understanding the Sahelian water budget through the isotopic composition of water vapor and precipitation

    Microsoft Academic Search

    Camille Risi; Sandrine Bony; Françoise Vimeux; Christian Frankenberg; David Noone; John Worden

    2010-01-01

    The goal of this paper is to investigate the added value of water isotopic measurements to estimate the relative influence of large-scale dynamics, convection, and land surface recycling on the Sahelian water budget. To this aim, we use isotope data in the lower tropospheric water vapor measured by the SCIAMACHY and TES satellite instruments and in situ precipitation data from

  5. Water vapor variability in the tropics and its links to dynamics and precipitation

    E-print Network

    Allan, Richard P.

    Water vapor variability in the tropics and its links to dynamics and precipitation Igor I. Zveryaev vapor and its links with radiative cooling and latent heating via precipitation are crucial to understanding feedbacks and processes operating within the climate system. Column-integrated water vapor (CWV

  6. Diode laser study of high-pressure water vapor spectroscopy

    NASA Astrophysics Data System (ADS)

    Nagali, Venu

    1999-10-01

    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 is described. A comprehensive review of line-shape modeling that highlights spectroscopic phenomena that become important at high pressures, such as the breakdown of the impact approximation in the wings and line mixing due to inelastic collisions, is presented. A decision tree and a road map to choose an appropriate line-shape model are introduced. Spectrally resolved measurements of H2O transitions near 7117 and 7185 cm-1 were performed at sub- atmospheric pressures and over a temperature range of 296-1000 K. Line-shape analyses of the recorded spectra yielded the temperature-dependent self-, N2-, CO2- and Ar broadened half- widths. The room-temperature (296K) half-widths and temperature exponents were determined to an average uncertainty of +/-7% and +/-9%, respectively. Good agreement was obtained between static-cell data recorded near 7117 cm-1 and simulations, based on measured line parameters and simple addition of Voigt line shapes, leading to the conclusions that: (1)effects due to line mixing are negligible for number densities up to at least 18 amagat, and (2)line shapes based on the impact and the additive approximations can be used in the development of spectroscopic diagnostics to monitor H2O in high-pressure combustion gases. Super-Lorentzian behavior was observed near 7185 cm-1 and is attributed to finite duration of collision effects neglected by impact line shapes. Water-vapor absorption features near 7117, 7185 and 7462 cm-1 were probed at pressures and temperatures to 65 atm. and 1800 K, in shock-heated mixtures of H2O in N2 and Ar. Temperature-dependent N2- and Ar-shift parameters for H2O absorption features were obtained by shifting the calculated spectra to match the recorded absorption data. The measured absorbance at the probed wavelengths was used to ascertain the accuracy of simulations based on current spectroscopic databases. The design of a sensor using diode lasers fixed at 7185.4 and 7117.4 cm -1 to monitor water vapor and temperature in high-pressure combustion gases is discussed.

  7. Potential energy of atmospheric water vapor and the air motions induced by water vapor condensation on different spatial scales

    E-print Network

    Anastassia M. Makarieva; Victor G. Gorshkov

    2010-03-29

    Basic physical principles are considered that are responsible for the origin of dynamic air flow upon condensation of water vapor, the partial pressure of which represents a store of potential energy in the atmosphere of Earth. Quantitative characteristics of such flow are presented for several spatial scales. It is shown that maximum condensation-induced velocities reach 160 m/s and are realized in compact circulation patterns like tornadoes.

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

    Microsoft Academic Search

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

    2003-01-01

    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

  9. Experimental Study on Condensation Heat Transfer of Ethanol-Water Vapor Mixtures on Vertical Micro-tubes

    NASA Astrophysics Data System (ADS)

    Chen, Xiping; Wang, Jinshi; Qin, Junchao; Chong, Daotong; Huang, Ronghai; Yan, Junjie

    2015-05-01

    The paper presents an experimental investigation of Marangoni condensation heat transfer of ethanol-water vapor mixtures on vertical micro-tubes with an outer diameter of 0.793 mm, 1.032 mm, and 1.221 mm. Experiments were performed over a wide range of ethanol mass fractions in vapor mixtures for different vapor velocities and pressures. Condensation heat transfer coefficients behaved nonlinear characteristics, increased, and then decreased with increasing vapor-to-surface temperature difference. Under the same experimental conditions, the condensation heat transfer coefficient at a 2 % ethanol mass fraction in vapor was the highest. At low ethanol mass fractions, the condensation heat transfer coefficient of the ethanol-water vapor mixture was 2 to 3 times greater than that for pure steam. The effect of vapor pressure and velocity on condensation heat transfer suggested a positive tendency on each micro-tube for all vapor mixtures with different ethanol mass fraction. Results showed that condensation heat transfer coefficients on micro-tubes with a diameter of 1.032 mm were higher than those on the other two micro-tubes, suggesting that there existed a critical diameter which gave the largest condensation heat transfer coefficient.

  10. Variations of stratospheric water vapor over the past three decades

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    We examine variations in water vapor in air entering the stratosphere through the tropical tropopause layer (TTL) over the past three decades in satellite data and in a trajectory model. Most of the variance can be explained by three processes that affect the TTL: the quasi-biennial oscillation, the strength of the Brewer-Dobson circulation, and the temperature of the tropical troposphere. When these factors act in phase, significant variations in water entering the stratosphere are possible. We also find that volcanic eruptions, which inject aerosol into the TTL, affect the amount of water entering the stratosphere. While there is clear decadal variability in the data and models, we find little evidence for a long-term trend in water entering the stratosphere through the TTL over the past 3 decades.

  11. Novel Approaches for Monitoring of Water Vapor Isotope Ratios: Plants, Lasers and Satellites

    Microsoft Academic Search

    Brent R. Helliker; David Noone

    \\u000a Atmospheric water vapor is a major component of the global hydrological cycle and the isotope ratio of that vapor is a key\\u000a tracer for both hydrological and biological processes. Yet little is known of the isotopic composition of vapor over any spatial\\u000a scale and through time because of challenges associated with collecting water vapor samples. Here we discuss alternate methods

  12. Fiber-Optic Gratings for Lidar Measurements of Water Vapor

    NASA Technical Reports Server (NTRS)

    Vann, Leila B.; DeYoung, Russell J.

    2006-01-01

    Narrow-band filters in the form of phase-shifted Fabry-Perot Bragg gratings incorporated into optical fibers are being developed for differential-absorption lidar (DIAL) instruments used to measure concentrations of atmospheric water vapor. The basic idea is to measure the relative amounts of pulsed laser light scattered from the atmosphere at two nearly equal wavelengths, one of which coincides with an absorption spectral peak of water molecules and the other corresponding to no water vapor absorption. As part of the DIAL measurement process, the scattered light is made to pass through a filter on the way to a photodetector. Omitting other details of DIAL for the sake of brevity, what is required of the filter is to provide a stop band that: Surrounds the water-vapor spectral absorption peaks at a wavelength of 946 nm, Has a spectral width of at least a couple of nanometers, Contains a pass band preferably no wider than necessary to accommodate the 946.0003-nm-wavelength water vapor absorption peak [which has 8.47 pm full width at half maximum (FWHM)], and Contains another pass band at the slightly shorter wavelength of 945.9 nm, where there is scattering of light from aerosol particles but no absorption by water molecules. Whereas filters used heretofore in DIAL have had bandwidths of =300 pm, recent progress in the art of fiber-optic Bragg-grating filters has made it feasible to reduce bandwidths to less than or equal to 20 pm and thereby to reduce background noise. Another benefit of substituting fiber-optic Bragg-grating filters for those now in use would be significant reductions in the weights of DIAL instruments. Yet another advantage of fiber-optic Bragg-grating filters is that their transmission spectra can be shifted to longer wavelengths by heating or stretching: hence, it is envisioned that future DIAL instruments would contain devices for fine adjustment of transmission wavelengths through stretching or heating of fiber-optic Bragg-grating filters nominally designed and fabricated to have transmission wavelengths that, in the absence of stretching, would be slightly too short.

  13. Cassini/CIRS Observations of Water Vapor in Titan's Stratosphere

    NASA Astrophysics Data System (ADS)

    Bjoraker, Gordon; Achterberg, R.; Anderson, C.; Samuelson, R.; Carlson, R.; Jennings, D.

    2008-09-01

    The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft has obtained spectra of Titan during most of the 44 flybys of the Cassini prime mission. Water vapor on Titan was first detected using whole-disk observations from the Infrared Space Observatory (Coustenis et al 1998, Astron. Astrophys. 336, L85-L89). CIRS data permit the retrieval of the latitudinal variation of water on Titan and some limited information on its vertical profile. Emission lines of H2O on Titan are very weak in the CIRS data. Thus, large spectral averages as well as improvements in calibration are necessary to detect water vapor. Water abundances were retrieved in nadir spectra at 55 South, the Equator, and at 19 North. Limb spectra of the Equator were also modeled to constrain the vertical distribution of water. Stratospheric temperatures in the 0.5 - 4.0 mbar range were obtained by inverting spectra of CH4 in the ?4 band centered at 1304 cm-1. The temperature in the lower stratosphere (4 - 20 mbar) was derived from fitting pure rotation lines of CH4 between 80 and 160 cm-1. The origin of H2O and CO2 is believed to be from the ablation of micrometeorites containing water ice, followed by photochemistry. This external source of water originates either within the Saturn system or from the interplanetary medium. Recently, Horst et al (J. Geophys. Res. 2008, in press) developed a photochemical model of Titan in which there are two external sources of oxygen. Oxygen ions (probably from Enceladus) precipitate into Titan's atmosphere to form CO at very high altitudes (1100 km). Water ice ablation at lower altitudes (700 km) forms H2O and subsequent chemistry produces CO2. CIRS measurements of CO, CO2, and now of H2O will provide valuable constraints to these photochemical models and improve our understanding of oxygen chemistry on Titan.

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

    PubMed

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

    2005-11-15

    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

  15. Vaporizing Vapor

    NSDL National Science Digital Library

    2012-08-03

    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.

  16. FTS Measurements of Submillimeter-Wave Atmospheric Opacity at Pampa la Bola III. Water Vapor, Liquid Water, and 183 GHz Water Vapor Line Opacities

    E-print Network

    Satoki Matsushita; Hiroshi Matsuo

    2003-02-03

    Further analysis has been made on the millimeter and submillimeter-wave (100-1600 GHz or 3 mm - 188 micron) atmospheric opacity data taken with the Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above sea level in northern Chile, which is the site of the Atacama Large Millimeter/submillimeter Array (ALMA). Time-sequence plots of millimeter and submillimeter-wave opacities show similar variations to each other, except for during the periods with liquid water (fog or clouds) in the atmosphere. Using millimeter and submillimeter-wave opacity correlations under two conditions, which are affected and not affected by liquid water, we succeeded to separate the measured opacity into water vapor and liquid water opacity components. The water vapor opacity shows good correlation with the 183 GHz water vapor line opacity, which is also covered in the measured spectra. On the other hand, the liquid water opacity and the 183 GHz line opacity show no correlation. Since only the water vapor component is expected to affect the phase of interferometers significantly, and the submillimeter-wave opacity is less affected by the liquid water component, it may be possible to use the submillimeter-wave opacity for a phase-correction of submillimeter interferometers.

  17. Study on internal water vapor content and related military standards of hermetic package devices

    Microsoft Academic Search

    Shao-Hua Yu; Cheng Gao; Xiang-Fen Wang

    2010-01-01

    Water vapor is one of the most important contaminants which caused devices failure. Internal water vapor content of hermetic package devices is closely related to the sealing performance, water absorption substances inside the package, leak plugging and other factors. The main mechanisms of leak plugging and water absorption by moisture absorbing substances are theoretically analyzed in this paper. Considering the

  18. Comparison of columnar water-vapor measurements from solar transmittance methods

    E-print Network

    Comparison of columnar water-vapor measurements from solar transmittance methods Beat Schmid to measure the columnar water vapor CWV by measuring solar transmittance in the 0.94- m water: 010.0010, 010.1110, 010.1320, 010.7340. 1. Introduction Solar transmittance methods can provide water

  19. Deuterium excess reveals diurnal sources of water vapor in forest air

    Microsoft Academic Search

    Chun-Ta LaiJames; James R. Ehleringer

    2011-01-01

    An understanding of atmospheric water vapor content and its isotopic composition is important if we are to be able to model\\u000a future water vapor dynamics and their potential feedback on future climate change. Here we present diurnal and vertical patterns\\u000a of water isotope ratios in forest air (?2Hv and ?18Ov) not observed previously. Water vapor observed at three heights over

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

    SciTech Connect

    Braun, John

    2006-02-06

    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.

  1. The seasonal variation of water vapor and ozone in the upper mesosphere: Implications for vertical transport and ozone photochemistry

    SciTech Connect

    Bevilacqua, R.M.; Summers, M.E. (Naval Research Lab., Washington, DC (United States)); Strobel, D.F. (Johns Hopkins Univ., Baltimore, MD (United States)); Olivero, J.J. (Pennsylvania State Univ., University Park (United States)); Allen, M. (California Inst. of Tech., Pasadena (United States))

    1990-01-20

    Ground-based microwave techniques have supplied the only long-term measurements of water vapor in the mesosphere. The authors review the entire current data base, which consists of measurements obtained in three separate experiments over an 8-year period. The data from all three experiments indicate that the water vapor seasonal variation at mid-latitudes in the upper mesosphere is dominated by an annual component with low mixing ratios in winter and high mixing ratios in summer. This suggests that the vertical distribution of water vapor in the upper mesosphere (up to 80 km) is controlled by advective rather than diffusive processes. This consistent with the low mesospheric K{sub zz} values ({approx} 10{sup 5} cm{sup 2}/s) deduced from the vertical gradient of the microwave water vapor measurements by Strobel et al. (1987). However, it is difficult to reconcile the predominantly annual water vapor variation with the semiannual variation in ozone at 78 km observed by the Solar Mesosphere Explorer. The authors perform a series of one-dimensional photochemical/vertical transport model calculations which verify that (within the context of the hydrogen/oxygen chemistry considered in the model), the seasonal variation of water vapor cannot be the mechanism for the semiannual ozone variation. This variation is either a manifestation of some heretofore unknown ozone photochemical mechanism, or it could be driven by a seasonal variation in the vertical transport of atomic oxygen from the thermosphere. One possible vertical transport scenario for producing the semiannual ozone variation (while retaining the annual water vapor variation) is described.

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

    NASA Astrophysics Data System (ADS)

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

    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.

  3. FTS Measurements of Submillimeter-Wave Atmospheric Opacity at Pampa la Bola III. Water Vapor, Liquid Water, and 183 GHz Water Vapor Line Opacities

    E-print Network

    Matsushita, S; Matsushita, Satoki; Matsuo, Hiroshi

    2003-01-01

    Further analysis has been made on the millimeter and submillimeter-wave (100-1600 GHz or 3 mm - 188 micron) atmospheric opacity data taken with the Fourier Transform Spectrometer (FTS) at Pampa la Bola, 4800 m above sea level in northern Chile, which is the site of the Atacama Large Millimeter/submillimeter Array (ALMA). Time-sequence plots of millimeter and submillimeter-wave opacities show similar variations to each other, except for during the periods with liquid water (fog or clouds) in the atmosphere. Using millimeter and submillimeter-wave opacity correlations under two conditions, which are affected and not affected by liquid water, we succeeded to separate the measured opacity into water vapor and liquid water opacity components. The water vapor opacity shows good correlation with the 183 GHz water vapor line opacity, which is also covered in the measured spectra. On the other hand, the liquid water opacity and the 183 GHz line opacity show no correlation. Since only the water vapor component is expec...

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

    Microsoft Academic Search

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

    1994-01-01

    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

  5. Thirty Meter Telescope Site Testing X: Precipitable Water Vapor

    NASA Astrophysics Data System (ADS)

    Otárola, A.; Travouillon, T.; Schöck, M.; Els, S.; Riddle, R.; Skidmore, W.; Dahl, R.; Naylor, D.; Querel, R.

    2010-04-01

    The results of the characterization of precipitable water vapor in the atmospheric column carried out in the context of identifying potential sites for the deployment of the Thirty Meter Telescope (TMT) are presented. Prior to starting the dedicated field campaign to look for a suitable site for the TMT, candidate sites were selected based on a climatology report utilizing satellite data that considered water vapor as one of the study variables. These candidate sites are all of tropical or subtropical location at geographic areas dominated by high-pressure systems. The results of the detailed on-site study, spanning a period of 4 yr, from early 2004 until the end of 2007, confirmed the global mean statistics provided in the previous reports based on satellite data, and also confirmed that all the candidate sites are exceptionally good for astronomy research. At the locations of these sites, the atmospheric conditions are such that the higher the elevation of the site, the drier it gets. However, the data analysis shows that during winter, San Pedro Mártir, a site about 230 m lower in elevation than Armazones, is drier than the Armazones site. This finding is attributed to the fact that Earth's atmosphere is largely unsaturated, leaving room for regional variability; it is useful in illustrating the relevance of in situ atmospheric studies for understanding the global and seasonal variability of potential sites for astronomy research. The results also show that winter and spring are the driest seasons at all of the tested sites, with Mauna Kea (in the northern hemisphere) and Tolonchar (in the southern hemisphere) being the tested sites with the lowest precipitable water vapor in the atmospheric column and the highest atmospheric transmission in the near and mid-infrared bands. This is the tenth article in a series discussing the TMT site-testing project.

  6. Oxidation of Ultra High Temperature Ceramics in Water Vapor

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    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.

  7. Optical fluorescent hygrometer for water vapor low concentration measurements

    NASA Astrophysics Data System (ADS)

    Yushkov, Vladimir; Lukjanov, Alexander; Merkulov, Serafim; Khaplanov, Mikhail; Shyshatzkaya, Ludmila; Gumbel, Jorg

    1995-09-01

    An optical hygrometer has been developed to make night-time measurements of water vapor in the upper atmosphere using the technique of photofragment fluorescence. Hygrometer uses the fluoroscence at wavelengths near 310 nm of excited OH molecules produced in the photodissociation of water molecules by UV radiation with hydrogen lamp (121.6 nm). A coaxial optical scheme is used. A compact hydrogen lamp is aligned along the axis of the instrument, inside the annular fast focusing optics. It provides the effective convergence of fluorescence from a large angle and thus increase the sensitivity of this method. The modulation of the hydrogen lamp with the frequency 1 kHz is used. Specially designed laboratory technique for calibration of the hygrometer is described. Total weight of the optical hygrometer is about 3 kg. It can be easily integrated with the Vaisala RS-80 radio sonde. This allows us to obtain reliable real-time data on temperature, pressure, and water vapor concentrations in the upper troposphere and stratosphere.

  8. Remote sensing evidence for regolith water vapor sources on Mars

    NASA Technical Reports Server (NTRS)

    Huguenin, R. L.; Clifford, S. M.

    1982-01-01

    McCord et al. (1977) have presented earth-based photometric imaging data of an event associated with the 1973 dust storm on Mars. The initial dust cloud in Solis Lacus and two regions to the north and south appeared anomalously bright at blue wavelengths. Water frosts, hazes, and/or clouds were identified, and it was suggested that the water responsible for these findings may have originated from Solis Lacus. More recently, a more intensive review of the observational record of Mars was undertaken. Earth-based telescope observations and data from the Mariner and Viking missions have revealed that Solis Lacus has been a center of repeated activity. Persistent activity in the vicinity of Noachis-Hellespontus and in the border regions of Syrtis Major was also discovered. A review of the observations is provided and possible interpretations are discussed. The obtained results appear to support the original proposal that Solis Lacus may be a source of water vapor. Noachis-Hellespontus seems to be a similar vapor source

  9. enhanced) in water vapor. The distribution of water ice throughout the solar nebula may

    E-print Network

    Utrecht, Universiteit

    enhanced) in water vapor. The distribution of water ice throughout the solar nebula may have varied of concentrations in different regions throughout the nebula. Gravitational settling will lead to concentrations of solids that are a few hundred times greater than that of the canonical solar nebula (14). Turbulent

  10. An alexandrite regenerative amplifier for water vapor and temperature measurements

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  11. Interactions of Water Vapor with Oxides at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    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.

  12. Sensing integrated water vapor along GPS ray paths

    NASA Astrophysics Data System (ADS)

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

    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.

  13. Airborne water vapor DIAL research: System development and field measurements

    NASA Technical Reports Server (NTRS)

    Higdon, Noah S.; Browell, Edward V.; Ponsardin, Patrick; Chyba, Thomas H.; Grossmann, Benoist E.; Butler, Carolyn F.; Fenn, Marta A.; Mayor, Shane D.; Ismail, Syed; Grant, William B.

    1992-01-01

    This paper describes the airborne differential absorption lidar (DIAL) system developed at the NASA Langley Research Center for remote measurement of water vapor (H2O) and aerosols in the lower atmosphere. The airborne H2O DIAL system was flight tested aboard the NASA Wallops Flight Facility (WFF) Electra aircraft in three separate field deployments between 1989 and 1991. Atmospheric measurements were made under a variety of atmospheric conditions during the flight tests, and several modifications were implemented during this development period to improve system operation. A brief description of the system and major modifications will be presented, and the most significant atmospheric observations will be described.

  14. Raman-shifted dye laser for water vapor DIAL measurements

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  15. 6.3-micron water-vapor-band derivatives

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    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.

  16. Water vapor measurement system in global atmospheric sampling program, appendix

    NASA Technical Reports Server (NTRS)

    Englund, D. R.; Dudzinski, T. J.

    1982-01-01

    The water vapor measurement system used in the NASA Global Atmospheric Sampling Program (GASP) is described. The system used a modified version of a commercially available dew/frostpoint hygrometer with a thermoelectrically cooled mirror sensor. The modifications extended the range of the hygrometer to enable air sample measurements with frostpoint temperatures down to -80 C at altitudes of 6 to 13 km. Other modifications were made to permit automatic, unattended operation in an aircraft environment. This report described the hygrometer, its integration with the GASP system, its calibration, and operational aspects including measurement errors. The estimated uncertainty of the dew/frostpoint measurements was + or - 1.7 Celsius.

  17. Investigation of the CARS spectrum of water vapor

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

  18. Reaction of water vapor with a clean liquid uranium surface

    SciTech Connect

    Siekhaus, W.

    1985-10-24

    To study the reaction of water vapor with uranium, we have exposed clean liquid uranium surfaces to H/sub 2/O under UHV conditions. We have measured the surface concentration of oxygen as a function of exposure, and determined the maximum attainable surface oxygen concentration X/sub 0//sup s/ as a function of temperature. We have used these measurements to estimate, close to the melting point, the solubility of oxygen (X/sub 0//sup b/, < 10/sup -4/) and its surface segregation coefficient ..beta../sup s/(> 10/sup 3/). 8 refs., 5 figs., 1 tab.

  19. Measurement of Low Amounts of Precipitable Water Vapor Using Ground-Based Millimeterwave Radiometry

    NASA Technical Reports Server (NTRS)

    Racette, Paul E.; Westwater, Ed R.; Han, Yong; Gasiewski, Albin J.; Klein, Marian; Cimini, Domenico; Jones, David C.; Manning, WIll; Kim, Edward J.; Wang, James R.

    2003-01-01

    Extremely dry conditions characterized by amounts of precipitable water vapor (PWV) as as 1-2 mm commonly occur in high-latitude regions during the winter months. While such atmospheres carry only a few percent of the latent heat energy compared to tropical atmospheres, the effects of low vapor amounts on the polar radiation budget - both directly through modulation of longwave radiation and indirectly through the formation of clouds - are considerable. Accurate measurements of precipitable water vapor (PWV) during such dry conditions are needed to improve polar radiation models for use in understanding and predicting change in the climatically sensitive polar regions. To this end, the strong water vapor absorption at 183.310 GHz provides a unique means of measuring low amounts of PWV. Weighting function analysis, forward model calculations based upon a 7-year radiosonde dataset, and retrieval simulations consistently predict that radiometric measurements made using several millimeter-wavelength (MMW) channels near the 183 GHz line, together with established microwave (MW) measurements at the 22.235 GHz water vapor line and -3 1 GHz atmospheric absorption window can be used to determine within 5% uncertainty the full range of PWV expected in the Arctic. This unique collective capability stands in spite of accuracy limitations stemming from uncertainties due to the sensitivity of the vertical distribution of temperature and water vapor at MMW channels. In this study the potential of MMW radiometry using the 183 GHz line for measuring low amounts of PWV is demonstrated both theoretically and experimentally. The study uses data obtained during March 1999 as part of an experiment conducted at the Department of Energy s Cloud and Radiation Testbed (CART) near Barrow, Alaska. Several radiometers from both NOAA and NASA were deployed during the experiment to provide the first combined MMW and MW ground-based data set during dry arctic conditions. Single-channel retrievals of PWV were performed using the MW and MMW data. Discrepancies in the retrieved values were found to be consistent with differences observed between measured brightness temperatures (TBs) and forward-modeled TBs based on concurrent radiosonde profiles. These discrepancies are greater than can be explained by measurement error alone and are attributed to absorption model uncertainty. We discuss here the measurements, retrieval technique, and line model discrepancies along with difficulties and potential of MMW/MW PWV measurement.

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

    NASA Technical Reports Server (NTRS)

    Stephens, Graeme L.

    1989-01-01

    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.

  1. The Water Vapor Abundance in Orion KL Outflows

    E-print Network

    J. Cernicharo; J. R. Goicoechea; F. Daniel; M. R. Lerate; M. J. Barlow; B. M. Swinyard; E. van Dishoeck; T. L. Lim; S. Viti; J. Yates

    2006-08-16

    We present the detection and modeling of more than 70 far-IR pure rotational lines of water vapor, including the 18O and 17O isotopologues, towards Orion KL. Observations were performed with the Long Wavelength Spectrometer Fabry-Perot (LWS/FP; R~6800-9700) on board the Infrared Space Observatory (ISO) between ~43 and ~197 um. The water line profiles evolve from P-Cygni type profiles (even for the H2O18 lines) to pure emission at wavelengths above ~100 um. We find that most of the water emission/absorption arises from an extended flow of gas expanding at 25+-5 kms^-1. Non-local radiative transfer models show that much of the water excitation and line profile formation is driven by the dust continuum emission. The derived beam averaged water abundance is 2-3x10^-5. The inferred gas temperature Tk=80-100 K suggests that: (i) water could have been formed in the "plateau" by gas phase neutral-neutral reactions with activation barriers if the gas was previously heated (e.g. by shocks) to >500 K and/or (ii) H2O formation in the outflow is dominated by in-situ evaporation of grain water-ice mantles and/or (iii) H2O was formed in the innermost and warmer regions (e.g. the hot core) and was swept up in ~1000 yr, the dynamical timescale of the outflow.

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

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Myers, Dwight L.

    2003-01-01

    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.

  3. Raman lidar profiling of atmospheric water vapor: Simultaneous measurements with two collocated systems

    NASA Technical Reports Server (NTRS)

    Goldsmith, J. E. M.; Bisson, Scott E.; Ferrare, Richard A.; Evans, Keith D.; Whiteman, David N.; Melfi, S. H.

    1994-01-01

    Raman lidar is a leading candidate for providing the detailed space- and time-resolved measurements of water vapor needed by a variety of atmospheric studies. Simultaneous measurements of atmospheric water vapor are described using two collocated Raman lidar systems. These lidar systems, developed at the NASA/Goddard Space Flight Center and Sandia National Laboratories, acquired approximately 12 hours of simultaneous water vapor data during three nights in November 1992 while the systems were collocated at the Goddard Space Flight Center. Although these lidar systems differ substantially in their design, measured water vapor profiles agreeed within 0.15 g/kg between altitudes of 1 and 5 km. Comparisons with coincident radiosondes showed all instruments agreed within 0.2 g/kg in this same altitude range. Both lidars also clearly showed the advection of water vapor in the middle troposphere and the pronounced increase in water vapor in the nocturnal boundary layer that occurred during one night.

  4. Retrieval of water vapor profiles from microwave radiometric measurements at 183 and 92 GHz

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Wilheit, T. T.; Chang, L. A.; Krupp, B. M.

    1988-01-01

    Microwave radiometric measurements made from an aircraft altitude of 20 km at 183.3 + or - 2, 183.3 + or - 5, and 183.3 + or - GHz, and at 92 GHz were used to retrieve the atmospheric water vapor profiles. Retrieval techniques shown to function properly in cloudfree conditions, were improved and extended to profile water vapor under moderate cloud cover conditions. The retrieved water vapor profiles compare favorably with those of rawinsonde observations at times nearly concurrent with the radiometric measurements.

  5. Characteristics of ? 18 O in precipitation over Eastern Monsoon China and the water vapor sources

    Microsoft Academic Search

    JianRong Liu; XianFang Song; GuoFu Yuan; XiaoMin Sun; Xin Liu; ShiQin Wang

    2010-01-01

    Monsoon circulation is an important carrier of water vapor transport, and it impacts the precipitation of the monsoonal regions\\u000a through the constraints and controls of large-scale water vapor transport and distributions as well as the water vapor balance.\\u000a An overall research on stable Hydrogen and Oxygen isotopes in precipitation over Eastern Monsoon China could benefit a comprehensive\\u000a understanding of the

  6. Development of a UAV-based differential absorption lidar for measuring atmospheric water vapor

    Microsoft Academic Search

    Brian William Thomas

    2003-01-01

    Differential Absorption Lidar (DIAL) is a remote sensing technique useful for making range resolved measurements of chemical species. A water vapor DIAL system was developed for use on a high altitude unmanned air vehicle (UAV), in order to study water vapor distribution in hurricanes. The system uses a diode-pumped Cr:LiSAF laser to probe water vapor absorption lines at or near

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

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Scofield, Rod; Vicente, Gilberto; Hodges, Mike

    2000-01-01

    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.

  9. Water Vapor and the Dynamics of Climate Changes

    NASA Astrophysics Data System (ADS)

    Schneider, Tapio; O'Gorman, Paul A.; Levine, Xavier J.

    2010-07-01

    Water vapor is not only Earth's dominant greenhouse gas. Through the release of latent heat when it condenses, it also plays an active role in dynamic processes that shape the global circulation of the atmosphere and thus climate. Here we present an overview of how latent heat release affects atmosphere dynamics in a broad range of climates, ranging from extremely cold to extremely warm. Contrary to widely held beliefs, atmospheric circulation statistics can change nonmonotonically with global-mean surface temperature, in part because of dynamic effects of water vapor. For example, the strengths of the tropical Hadley circulation and of zonally asymmetric tropical circulations, as well as the kinetic energy of extratropical baroclinic eddies, can be lower than they presently are both in much warmer climates and in much colder climates. We discuss how latent heat release is implicated in such circulation changes, particularly through its effect on the atmospheric static stability, and we illustrate the circulation changes through simulations with an idealized general circulation model. This allows us to explore a continuum of climates, to constrain macroscopic laws governing this climatic continuum, and to place past and possible future climate changes in a broader context.

  10. TES/Aura L2 Water Vapor (H2O) Limb (TL2H2OL)

    Atmospheric Science Data Center

    2015-02-06

    TES/Aura L2 Water Vapor (H2O) Limb (TL2H2OL) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Water Vapor Spatial Coverage:  27 x 23 km Limb ... Access: OPeNDAP Parameters:  H2O Water Volume Mixing Radio Precision Vertical Resolution Order ...

  11. TES/Aura L2 Water Vapor (H2O) Limb (TL2H2OLS)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Water Vapor (H2O) Limb (TL2H2OLS) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Water Vapor Spatial Coverage:  27 x 23 km Limb ... Access:  OPeNDAP Parameters:  H2O Water Volume Mixing Radio Precision Vertical Resolution Order ...

  12. Influence of condensate evaporation on water vapor and its stable isotopes in a GCM

    E-print Network

    Influence of condensate evaporation on water vapor and its stable isotopes in a GCM Jonathon S May 2009; published 17 June 2009. [1] The direct effect of condensate evaporation on atmospheric water. S., A. H. Sobel, and G. A. Schmidt (2009), Influence of condensate evaporation on water vapor

  13. Water vapor microwave continuum absorption: A comparison of measurements and models

    Microsoft Academic Search

    Philip W. Rosenkranz

    1998-01-01

    Measurements, made in different laboratories, of absorption by water vapor in microwave windows are compared with models for the water vapor continuum. A reanalysis of some of these measurements leads to the conclusion that the laboratory data are best represented by a combination of Liebe's (1987) millimeter-wave propagation model (MPM) for the foreign-broadened component of the water continuum and the

  14. Vapor pressures in the ternary system water-nitric acid-sulfuric acid and low temperatures

    Microsoft Academic Search

    A. Jaecker-Voirol; J. L. Ponche; P. Mirabel

    1990-01-01

    The partial vapor pressures over liquid or supercooled solutions of water and nitric acid and of water and sulfuric acid are calculated for temperatures below 0 C. From these results, the partial vapor pressures over the tenary system water-nitric acid-sulfuric acid (liquid or supercooled) have been estimated and compared with the available experimental data of Vandoni (1944) at 0 C.

  15. Numerical modeling of water injection into vapor-dominatedgeothermal reservoirs

    SciTech Connect

    Pruess, Karsten

    2006-11-06

    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 lines.This report reviews thermodynamic andhydrogeologic conditions and mechanisms that play an important role inreservoir response to water injection. An existing general-purposereservoir simulator has been enhanced to allow modeling of injectioneffects in heterogeneous fractured reservoirs in three dimensions,including effects of non-condensible gases of different solubility.Illustrative applications demonstrate fluid flow and heat transfermechanisms that are considered crucial for developing approaches to insitu abatement of NCGs.

  16. Continuous field measurements of ?D in water vapor by open-path Fourier transform infrared spectrometry

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Liu, Wenqing; Zhang, Tianshu

    2012-12-01

    The stable isotopes in atmospheric water vapor contain rich information on the hydrologic cycles and gaseous exchange processes between biosphere and atmosphere. About one-week field experiment was conducted to continuously measure the isotope composition of water vapor in ambient air using an open-path FTIR system. Mixing ratios of H2 16O and HD16O were measured simultaneously. Analysis of water vapor isotopes revealed that the variations of H2 16O and HD16O were highly related. Mixing ratios of both isotopes varied considerably on a daily timescale or between days, with no obvious diurnal cycle, whereas the deuterium isotopic [delta]D showed clear diel cycle. The results illustrated that the correlation between [delta]D and H2O mixing ratio was relatively weak, which was also demonstrated by the Keeling plot analysis with the whole data. Yet the further Keeling analysis on a daily timescale displayed more obvious linear relationship between [delta]D and the total H2O concentration. All daily isotopic values of evapotranspiration source were obtained, with the range between -113.93±10.25‰ and -245.63±17.61‰ over the observation period.

  17. A Raman lidar to measure water vapor in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Froidevaux, Martin; Higgins, Chad W.; Simeonov, Valentin; Ristori, Pablo; Pardyjak, Eric; Serikov, Ilya; Calhoun, Ronald; Bergh, Hubert van den; Parlange, Marc B.

    2013-01-01

    A new multi-telescope scanning Raman lidar designed to measure the water vapor mixing ratio in the atmospheric boundary layer for a complete diurnal cycle with high resolution spatial (1.25 m) and temporal (1 s) resolutions is presented. The high resolution allows detailed measurements of the lower atmosphere and offers new opportunities for evaporation and boundary layer research, atmospheric profiling and visualization. This lidar utilizes a multi-telescope design that provides for an operational range with a nearly constant signal-to-noise ratio, which allows for statistical investigations of atmospheric turbulence. This new generation ground-based water vapor Raman lidar is described, and first observations from the Turbulent Atmospheric Boundary Layer Experiment (TABLE) are presented. Direct comparison with in-situ point measurements obtained during the field campaign demonstrate the ability of the lidar to reliably measure the water vapor mixing ratio. Horizontal measurements taken with time are used to determine the geometric characteristics of coherent structures. Vertical scans are used to visualize nocturnal jet features, layered structures within a stably stratified atmosphere and the internal boundary layer structure over a lake.

  18. Comparison of aerosol optical properties and water vapor among ground and airborne lidars and Sun photometers during TARFOX

    Microsoft Academic Search

    R. Ferrare; S. Ismail; E. Browell; V. Brackett; M. Clayton; S. Kooi; S. H. Melfi; D. Whiteman; G. Schwemmer; K. Evans; P. Russell; J. Livingston; B. Schmid; B. Holben; L. Remer; A. Smirnov; P. V. Hobbs

    2000-01-01

    We compare aerosol optical thickness (AOT) and precipitable water vapor (PWV) measurements derived from ground and airborne lidars and Sun photometers during the Tropospheric Aerosol Radiative Forcing Observational Experiment. Such comparisons are important to verify the consistency between various remote sensing measurements before employing them in any assessment of the impact of aerosols on the global radiation balance. Total scattering

  19. A review of selected aspects of the effect of water vapor on fission gas release from uranium oxycarbide

    Microsoft Academic Search

    1994-01-01

    A selective review is presented of previous measurements and the analysis of experiments on the effect of water vapor on fission gas release from uranium oxycarbide. Evidence for the time-dependent composition of the uranium oxycarbide fuel; the diffusional release of fission gas; and the initial, rapid and limited release of stored fission gas is discussed. In regard to the initial,

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

    SciTech Connect

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

    2013-06-01

    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.

  1. Water Vapor Radiometer for ALMA: Optical Design and Verification

    NASA Astrophysics Data System (ADS)

    Cherednichenko, S.; Emrich, A.; Peacocke, T.

    2010-03-01

    Atacama Large Millimeter wave Array (ALMA) is being built at a high altitude Atacama Desert in Chile. It will consist of 50 12m telescopes with heterodyne instruments to cover a large frequency range from about 30GHz to nearly 1THz. In order to facilitate the interferometer mode of operation all receivers have to be phase synchronized. It will be accomplished by phase locking of all local oscillators from a single reference source. However, a noticeable part of the phase error is caused as the signal propagates through the Earth atmosphere. Since this effect originates from the fluctuations of water vapors, it can be accounted for by carefully measuring the spectral width of one of water vapor resonance absorption lines. This will be done with a submillimeter heterodyne radiometer, Water Vapor Radiometer (WVR). WVR will measure the sky brightness temperature in the beam path of every telescope across the 183GHz water line with a spectral resolution of about 1GHz. Accuracy of the calculated optical delay is determined by the combination of the radiometric accuracy of the WVR and of the errors originated in the WVR illumination of the telescope. We will describe major challenges in the design of the WVR to comply with the stringent requirements set to the WVR. Several approaches to simulate the quasioptical waveguide which brings the signal from the telescope's subreflector to the mixer horn, were used: fundamental mode Gaussian beam propagation, combined ray tracing with diffraction effects (using package ZEMAX), and a full vector electromagnetic simulations (using GRASP). The computational time increases rapidly from the first method to the last one. We have found that ZEMAX results are quite close to the one from GRASP, however obtained with nearly instant computation, which allows multiple iterations during system optimization. The beam pattern of the WVR and of WVR with the optical Relay (used to bring the signal from the telescope's main axis to the WVR input window) was measured by a scalar beam scan at four planes in the far field. The experimental results correspond to the simulated ones with a high accuracy. The WVR illuminates the telescope subreflector with a spillover of less than 1.5% while maintaining high aperture efficiency. We developed an approach to calculate the beam center position at the subreflector (with is at 6m from the WVR) from our test data (at maximum 2m from the WVR) in order confirm the maximum beam deviation does not exceed 20mm, i.e. 1/15 of the beam width.

  2. Theoretical Calculation and Validation of the Water Vapor Continuum Absorption

    NASA Technical Reports Server (NTRS)

    Ma, Qiancheng; Tipping, Richard H.

    1998-01-01

    The primary objective of this investigation is the development of an improved parameterization of the water vapor continuum absorption through the refinement and validation of our existing theoretical formalism. The chief advantage of our approach is the self-consistent, first principles, basis of the formalism which allows us to predict the frequency, temperature and pressure dependence of the continuum absorption as well as provide insights into the physical mechanisms responsible for the continuum absorption. Moreover, our approach is such that the calculated continuum absorption can be easily incorporated into satellite retrieval algorithms and climate models. Accurate determination of the water vapor continuum is essential for the next generation of retrieval algorithms which propose to use the combined constraints of multi-spectral measurements such as those under development for EOS data analysis (e.g., retrieval algorithms based on MODIS and AIRS measurements); current Pathfinder activities which seek to use the combined constraints of infrared and microwave (e.g., HIRS and MSU) measurements to improve temperature and water profile retrievals, and field campaigns which seek to reconcile spectrally-resolved and broad-band measurements such as those obtained as part of FIRE. Current widely used continuum treatments have been shown to produce spectrally dependent errors, with the magnitude of the error dependent on temperature and abundance which produces errors with a seasonal and latitude dependence. Translated into flux, current water vapor continuum parameterizations produce flux errors of order 10 W/ml, which compared to the 4 W/m' magnitude of the greenhouse gas forcing and the 1-2 W/m' estimated aerosol forcing is certainly climatologically significant and unacceptably large. While it is possible to tune the empirical formalisms, the paucity of laboratory measurements, especially at temperatures of interest for atmospheric applications, preclude tuning the empirical continuum models over the full spectral range of interest for remote sensing and climate applications. Thus, we propose to further develop and refine our existing far-wing formalism to provide an improved treatment applicable from the near-infrared through the microwave. Based on the results of this investigation, we will provide to the remote sensing/climate modeling community a practical and accurate tabulation of the continuum absorption covering the near-infrared through the microwave region of the spectrum for the range of temperatures and pressures of interest for atmospheric applications.

  3. Theoretical Calculation and Validation of the Water Vapor Continuum Absorption

    NASA Technical Reports Server (NTRS)

    Ma, Qiancheng; Tipping, Richard H.

    1998-01-01

    The primary objective of this investigation is the development of an improved parameterization of the water vapor continuum absorption through the refinement and validation of our existing theoretical formalism. The chief advantage of our approach is the self-consistent, first principles, basis of the formalism which allows us to predict the frequency, temperature and pressure dependence of the continuum absorption as well as provide insights into the physical mechanisms responsible for the continuum absorption. Moreover, our approach is such that the calculated continuum absorption can be easily incorporated into satellite retrieval algorithms and climate models. Accurate determination of the water vapor continuum is essential for the next generation of retrieval algorithms which propose to use the combined constraints of multispectral measurements such as those under development for EOS data analysis (e.g., retrieval algorithms based on MODIS and AIRS measurements); current Pathfinder activities which seek to use the combined constraints of infrared and microwave (e.g., HIRS and MSU) measurements to improve temperature and water profile retrievals, and field campaigns which seek to reconcile spectrally-resolved and broad-band measurements such as those obtained as part of FIRE. Current widely used continuum treatments have been shown to produce spectrally dependent errors, with the magnitude of the error dependent on temperature and abundance which produces errors with a seasonal and latitude dependence. Translated into flux, current water vapor continuum parameterizations produce flux errors of order 10 W/sq m, which compared to the 4 W/sq m magnitude of the greenhouse gas forcing and the 1-2 W/sq m estimated aerosol forcing is certainly climatologically significant and unacceptably large. While it is possible to tune the empirical formalisms, the paucity of laboratory measurements, especially at temperatures of interest for atmospheric applications, preclude tuning, the empirical continuum models over the full spectral range of interest for remote sensing and climate applications. Thus, we propose to further develop and refine our existing, far-wing formalism to provide an improved treatment applicable from the near-infrared through the microwave. Based on the results of this investigation, we will provide to the remote sensing/climate modeling community a practical and accurate tabulation of the continuum absorption covering the near-infrared through the microwave region of the spectrum for the range of temperatures and pressures of interest for atmospheric applications.

  4. Cold Water Vapor in the Barnard 5 Molecular Cloud

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    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 ((is) approximately 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.

  5. Water vapor adsorption onto nanostructured carbide derived carbon (CDC)

    NASA Astrophysics Data System (ADS)

    Gupta, Prateek

    Carbide derived carbon, CDC, is a layer synthesized by the selective etching of a metal from a metal carbide. The resulting carbon material that remains is a layer with several unique and useful properties. Properties of CDC are the low friction coefficient of CDC, the high specific surface area of CDC, and the tunable porosity of CDC. Although these properties have been well studied, there has not been much work done into looking the affect that adsorbed water plays on properties of CDC. It is important to understand the affect of water has on CDC since CDC will be used in atmospheric conditions where it will be constantly exposed to water vapor, in the form of humidity in the environment. To test the effect that water has on CDC, samples were synthesized under a variety of different conditions. Once the samples were synthesized, they were placed in controlled humidity environments. The amount of water adsorbed was determined and the resulting isotherms were plotted. The isotherms showed that chlorinated CDC has a microporous structure. However CDC that was post-treated in either a hydrogen gas blend or high purity argon gas has structure that contained mesopores. The post-treated results also show that the friction coefficient of CDC increases when it is annealed in an inert environment at elevated temperatures. Finally contrary to previous work, residual chlorine in the CDC does not play a role in the friction coefficient of CDC.

  6. The stability of Au-chloride complexes in water vapor at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Archibald, S. M.; Migdisov, A. A.; Williams-Jones, A. E.

    2001-12-01

    The solubility of gold in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 300 to 360°C and pressures up to 144 bars. Results of these experiments show that the solubility of gold in the vapor phase is significant and increases with increasing fHCl and fH 2O . This behavior of gold is attributed to formation of hydrated gold-chloride gas species, interpreted to have a gold-chlorine ratio of 1:1 and a hydration number varying from 5 at 300°C to 3 at 360°C. These complexes are proposed to have formed through the following reaction: Ausolid+ m· HClgas+ n· H2Ogas= AuClm·( H2O) ngas+ m/2· H2gas which was determined to have log K values of -17.28 ± 0.36 at 300°C, -18.73 ± 0.66 at 340°C, and -18.74 ± 0.43 at 360°C. Gold solubility in the vapor was retrograde, i.e., it decreased with increasing temperature, possibly as a result of the inferred decrease in hydration number. Calculations based on our data indicate that at 300°C and fO 2-pH conditions, encountered in high sulfidation epithermal systems, the vapor phase can transport up to 6.6 ppb gold, which would be sufficient to form an economic deposit (e.g., Nansatsu, Japan; 36 tonnes) in ˜ 30,000 yr.

  7. Water vapor toward starless cores: The Herschel view

    NASA Astrophysics Data System (ADS)

    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

    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.

  8. The reaction kinetics of lithium salt with water vapor

    NASA Astrophysics Data System (ADS)

    Balooch, M.; Dinh, L. N.; Calef, D. F.

    2002-06-01

    The interaction of lithium salt (LiH and/or LiD) with water vapor in the partial pressure range of 10 -5-2657 Pa has been investigated. The reaction probability of water with LiH cleaved in an ultra high vacuum environment was obtained using the modulated molecular beam technique. This probability was 0.11 and independent of LiH surface temperature, suggesting a negligible activation energy for the reaction in agreement with quantum chemical calculations. The value gradually reduced, however, to 0.007 as the surface concentration of oxygen containing product approached full coverage. As the film grew beyond a monolayer, the phase lag of hydrogen product increased from 0 °C to 20 °C and the reaction probability reduced further until it approached our detection limit (˜10 -4). This phase lag was attributed to a diffusion-limited process in this regime. For micrometer thick hydroxide films grown in high moisture concentration environment on LiD and LiH, the reaction probability reduced to ˜4×10 -7 and was independent of exposure time. In this regime of thick hydroxide films (LiOH and/or LiOD), microcracks generated in the films to release stress provided easier pathways for moisture to reach the interface. A modified microscope, capable of both atomic force microscopy and nanoindentation, was also employed to investigate the surface morphology of hydroxide monohydrate (LiOH · H 2O and/or LiOD · H 2O) grown on hydroxide at high water vapor partial pressures and the kinetics of this growth.

  9. The diel cycle of water vapor in west Greenland

    NASA Astrophysics Data System (ADS)

    Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.

    2014-08-01

    We present a study of the dynamics of small-scale (~100 km) atmospheric circulation in west Greenland which is dominated by interactions of marine and continental air masses. Water vapor concentration and isotopic ratios measured continuously over a 25 day period in Kangerlussuaq, Greenland were used to monitor the convergence of easterly katabatic winds and westerly sea breezes that form a front between the dry, isotopically depleted, glacial air mass and the moist, isotopically enriched, marine air mass. During the latter 16 days of the measurement period, an interval with no large-scale synoptic interference, the inland penetration of the sea breeze controlled the largest day-to-day humidity and vapor isotopic variations. Kangerlussuaq experienced sea breezes in the afternoon on 9 days, consistent with the long-term average of such occurrences on 56% of days in July and August. The inland position of the sea breeze front is controlled by the katabatic wind strength, which is stronger during times of reduced cloud coverage and/or higher-pressure gradient between the coast and the Greenland ice sheet. The position and movement of the front will likely respond to changes in the general atmospheric circulation and regional radiation balance resulting from global warming, which will, in turn, impact the local hydrological cycle and ecosystem processes.

  10. Precipitable Water Vapor: Considerations on the water vapor scale height, dry bias of the radiosonde humidity sensors, and spatial and temporal variability of the humidity field

    E-print Network

    Otarola, Angel C; Kerber, Florian

    2011-01-01

    The Thirty Meter Telescope (TMT) and the European Extremely Large Telescope (E-ELT) site testing teams have recently finalized their site testing studies. Since atmospheric water vapor is the dominant source of absorption and increased thermal background in the infrared, both projects included precipitable water vapor (PWV) measurements in their corresponding site testing campaigns. TMT planned to monitor PWV at the sites of interest by means of using infrared radiometers. Technical failures and calibration issues prevented them from having a sufficiently long PWV time-series to characterize the sites using this method. Therefore, for the sites in Chile TMT used surface water vapor density measurements, which taken together with an assumed water vapor scale height, allowed for the estimation of PWV. On the other hand, the E-ELT team conducted dedicated PWV measurement campaigns at two of their observatory sites using radiosonde soundings to validate historical time-series of PWV reconstructed by way of a spec...

  11. Solar Mesosphere Explorer observations of stratospheric and mesospheric water vapor

    NASA Technical Reports Server (NTRS)

    Jakosky, Bruce M.; Thomas, Gary E.; Rusch, David W.; Barth, Charles A.; Lawrence, George M.; Olivero, John J.; Clancy, R. Todd; Sanders, Ryan W.; Knapp, Barry G.

    1988-01-01

    It is noted that while the SME (Solar Mesosphere Explorer) data is consistent with the earlier LIMS (Limb Infrared Monitor of the Stratosphere) results, its interpretation is complicated by aerosol contamination, particularly at altitudes below 35 km. This contamination arose from several volcanic eruptions, including that of El Chichon. Analyses are reported of a subset of data from the SME satellite, concentrating primarily on the period January through March 1982 so as to avoid contamination from the El Chichon volcanic aerosol. The SME observations of water vapor between 20 and 60 km were inverted for the first three months of 1982 as well as for selected additional periods. Reasonable results are obtained at locations where no contamination by aerosol is suspected.

  12. The role of water vapor in climate. A strategic research plan for the proposed GEWEX water vapor project (GVaP)

    NASA Technical Reports Server (NTRS)

    Starr, D. OC. (editor); Melfi, S. Harvey (editor)

    1991-01-01

    The proposed GEWEX Water Vapor Project (GVaP) addresses fundamental deficiencies in the present understanding of moist atmospheric processes and the role of water vapor in the global hydrologic cycle and climate. Inadequate knowledge of the distribution of atmospheric water vapor and its transport is a major impediment to progress in achieving a fuller understanding of various hydrologic processes and a capability for reliable assessment of potential climatic change on global and regional scales. GVap will promote significant improvements in knowledge of atmospheric water vapor and moist processes as well as in present capabilities to model these processes on global and regional scales. GVaP complements a number of ongoing and planned programs focused on various aspects of the hydrologic cycle. The goal of GVaP is to improve understanding of the role of water vapor in meteorological, hydrological, and climatological processes through improved knowledge of water vapor and its variability on all scales. A detailed description of the GVaP is presented.

  13. Projected Regime Shift in Arctic Cloud and Water Vapor Feedbacks

    NASA Technical Reports Server (NTRS)

    Chen, Yonghua; Miller, James R.; Francis, Jennifer; Russel, Gary L.

    2011-01-01

    The Arctic climate is changing faster than any other large-scale region on Earth. A variety of positive feedback mechanisms are responsible for the amplification, most of which are linked with changes in snow and ice cover, surface temperature (T(sub s)), atmospheric water vapor (WV), and cloud properties. As greenhouse gases continue to accumulate in the atmosphere, air temperature and water vapor content also increase, leading to a warmer surface and ice loss, which further enhance evaporation and WV. Many details of these interrelated feedbacks are poorly understood, yet are essential for understanding the pace and regional variations in future Arctic change. We use a global climate model (Goddard Institute for Space Studies, Atmosphere-Ocean Model) to examine several components of these feedbacks, how they vary by season, and how they are projected to change through the 21st century. One positive feedback begins with an increase in T(sub s) that produces an increase in WV, which in turn increases the downward longwave flux (DLF) and T(sub s), leading to further evaporation. Another associates the expected increases in cloud cover and optical thickness with increasing DLF and T(sub s). We examine the sensitivities between DLF and other climate variables in these feedbacks and find that they are strongest in the non-summer seasons, leading to the largest amplification in Ts during these months. Later in the 21st century, however, DLF becomes less sensitive to changes in WV and cloud optical thickness, as they cause the atmosphere to emit longwave radiation more nearly as a black body. This regime shift in sensitivity implies that the amplified pace of Arctic change relative to the northern hemisphere could relax in the future.

  14. Pointed water vapor radiometer corrections for accurate Global Positioning System surveying

    Microsoft Academic Search

    Randolph Ware; Christian Rocken; Fredrick Solheim; Teresa Van Hove; Chris Alber; James Johnson

    1993-01-01

    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

  15. GPS Meteorology: Remote Sensing of Atmospheric Water Vapor Using the Global Positioning System

    Microsoft Academic Search

    Michael Bevis; Steven Businger; Thomas A. Herring; Christian Rocken; Richard A. Anthes; Randolph H. Ware

    1992-01-01

    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

  16. Feasibility of Tropospheric Water Vapor Profiling Using Infrared Heterodyne Differential Absorption Lidar

    Microsoft Academic Search

    C. J. Grund; R. M. Hardesty; B. J. Rye

    Continuous, high quality profiles of water vapor, free of column lengths can be compared to determine the range- systematic bias and of moderate temporal and spatial resolved concentration. Most DIAL systems used for resolution, acquired over long periods at low operational monitoring water vapor have operated at wavelengths of and maintenance cost, are fundamental to the success of about 700

  17. First water vapor measurements at 183 GHz from the high alpine station Jungfraujoch

    Microsoft Academic Search

    Andreas Siegenthaler; Olivier Lezeaux; Dietrich G. Feist; Niklaus Kämpfer

    2001-01-01

    During six months in 1999, we observed the water vapor emission line at 183.31 GHz with a microwave radiometer at the high alpine site Jungfraujoch in Switzerland. We retrieved statistics on the atmospheric transmission and profiles of stratospheric water vapor on selected days. Our site seems well suited for observations of this spectral line

  18. Ground-based Millimeter-wave Observations of Water Vapor Emission (183 GHz) at Atacama, Chile

    Microsoft Academic Search

    T. Kuwahara; A. Mizuno; T. Nagahama; H. Maezawa; A. Morihira; N. Toriyama; S. Murayama; M. Matsuura; T. Sugimoto; S. Asayama

    2006-01-01

    We report a ground-based mm-wave observation of the stratospheric and mesospheric water vapor in Atacama Chile in December 2005 Stratospheric water vapor is an important trace gas in the middle atmosphere because it is a source of odd hydrogen influencing ozone chemistry and is one of the greenhouse gases which affect the radiation balance in the middle atmosphere Previous observations

  19. Remotely operated infrared radiometer for the measurement of atmospheric water vapor

    E-print Network

    Naylor, David A.

    is the multi-channel radiometric observation of the 183 GHz water vapor emission line1 . In this method antenna of the atmosphere in this spectral region) and the risk of radio frequency interference from the 183 GHz local brightness temperature measurements at three frequencies close to the water vapor line transition at 183

  20. Retrieval of atmospheric water vapor profiles using radiometric measurements at 183 and 90 GHz

    Microsoft Academic Search

    R. Lutz; T. T. Wilheit; J. R. Wang; R. K. Kakar

    1991-01-01

    The algorithm developed by T. Wilheim (1990) dealt with the retrieval of water vapor profiles from microwave radiometric measurements, even in the presence of clouds. This algorithm was tested with the radiometric measurements near 90 and 183 GHz frequencies, and the results are presented. It is shown that the retrieved water vapor profiles were in general agreement with those derived

  1. Temperature dependence of water-vapor absorption in the wing of the 183 GHz line

    Microsoft Academic Search

    A. Bauer; B. Duterage; M. Godon

    1986-01-01

    Absolute absorption rates of water vapor have been measured in the laboratory in the high-frequency wing of the 183 GHz line. Measurements have been carried out for pure water vapor and mixtures with N2 at atmospheric pressure. Pressure- and temperature-dependences are compared with models involving several types of lineshapes.

  2. Alexandrite laser characterization and airborne lidar developments for water vapor DIAL measurements

    NASA Technical Reports Server (NTRS)

    Ponsardin, P.; Higdon, N. S.; Grossmann, B. E.; Browell, E. V.

    1991-01-01

    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.

  3. High Temperature Corrosion of Silicon Carbide and Silicon Nitride in Water Vapor

    NASA Technical Reports Server (NTRS)

    Opila, E. J.; Robinson, Raymond C.; Cuy, Michael D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    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.

  4. Isotopic Variability in Surface Water Vapor and Precipitation in the Upper Midwest, USA

    Microsoft Academic Search

    N. M. Schultz; T. J. Griffis; J. M. Baker; X. Lee; M. Erickson; X. Zhang; W. Xiao; N. Hu

    2010-01-01

    The isotopic composition of surface water vapor and precipitation provides important information about the moisture source characteristics and subsequent transport processes and phase changes in the atmosphere. The objective of this research is to investigate the characteristics of delta18O, deltaD, and deuterium excess (d) in surface water vapor and precipitation in Rosemount, MN, a continental site characterized by hot, humid

  5. GPS Occultation Profiling of Low Latitude Free Tropospheric Water Vapor (Invited)

    Microsoft Academic Search

    E. R. Kursinski; A. L. Kursinski

    2010-01-01

    We present an overview of our GPS radio occultation (RO) water vapor related research and applications. Orbiting GPS receivers profile the free tropospheric, low latitude water vapor distribution up to ~9 km altitude. GPS RO provides 200 m vertical resolution, routine cloud penetration and more than 2000 globally distributed, occultation profiles per day with COSMIC and MetOp-A. We focus on

  6. Environmental controls over carbon dioxide and water vapor exchange of terrestrial vegetation

    Microsoft Academic Search

    B. E. Law; E. Falgeb; L. Guc; D. D. Baldocchic; P. Bakwind; P. Berbigiere; K. Davisf; A. J. Dolmang; M. Falkh; J. D. Fuentesi; A. Goldsteinc; A. Granierj; A. Grellek; D. Hollingerl; I. A. Janssensm; P. Jarvisn; N. O. Jenseno; G. Katulp; Y. Mahliq; G. Matteuccir; T. Meyerss; R. Monsont; W. Mungeru; W. Oechelv; R. Olsonw; K. Pilegaardx; K. T. Paw Uh; H. Thorgeirssony; R. Valentinir; S. Vermaz; T. Vesala; K. Wilsons; S. Wofsyu

    2002-01-01

    The objective of this research was to compare seasonal and annual estimates of CO2 and water vapor exchange across sites in forests, grasslands, crops, and tundra that are part of an international network called FLUXNET, and to investigating the responses of vegetation to environmental variables. FLUXNETs goals are to understand the mechanisms controlling the exchanges of CO2, water vapor and

  7. Observations of precipitable water vapor fluctuations in convective boundary layer via microwave interferometry

    Microsoft Academic Search

    X. M. Shao; R. C. Carlos; M. W. Kirkland; C.-Y. J. Kao; A. R. Jacobson

    1999-01-01

    At microwave frequencies, each centimeter of precipitable water vapor (PWV) causes about 6.45 cm of extra electrical path length relative to the ``dry'' air. The fluctuations of the water vapor dominate the changes of the effective path length through the atmosphere in a relatively short time period of a few hours. In this paper we describe a microwave interferometer developed

  8. Zero-frequency refractivity of water vapor, comparison of Debye and van-Vleck Weisskopf

    E-print Network

    Oklahoma State University

    0.5 MHz to microwave, mm-waves and THz frequencies. This result removes a long standing discrepancy. K. Chatterjee, "The dielectric constant of water vapor in the microwave region," J. Appl. Phys. 23, and A. Abou-Zeid, "High-accuracy determination of water vapor refractivity by length interferometry

  9. Vapor Pressure of Water at Its Triple Point: Highly Accurate Value

    Microsoft Academic Search

    L. A. Guildner; D. P. Johnson; F. E. Jones

    1976-01-01

    The vapor pressure of water at its triple point was measured with greatly increased accuracy. The triple point was realized with newly designed equipment that enhanced the stability of the pressure and permitted any air released from solution to be removed by pumping. A diaphragm pressure transducer separated the water vapor from the helium used to transmit the pressure to

  10. A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties

    E-print Network

    A Fixed Point Charge Model for Water Optimized to the Vapor-Liquid Coexistence Properties Jeffrey R@ipst.umd.edu #12;1 Abstract A new fixed-point charge potential model for water has been developed, targeting the accurate prediction of the vapor-liquid coexistence properties over a broad temperature range. The model

  11. Observational evidence of changes in water vapor, clouds, and radiation at the ARM SGP site

    E-print Network

    Dong, Xiquan

    Observational evidence of changes in water vapor, clouds, and radiation at the ARM SGP site Xiquan then increased until the present. Using 8 years of data collected at the ARM Southern Great Plains (SGP) surface evidence of changes in water vapor, clouds, and radiation at the ARM SGP site, Geophys. Res. Lett., 33, L

  12. A Two-Line Absorption Instrument for Scramjet Temperature and Water Vapor Concentration Measurement in HYPULSE

    NASA Technical Reports Server (NTRS)

    Tsai, C. Y.

    1998-01-01

    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.

  13. John Arthur McLees, Jr. Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water at

    E-print Network

    Rochelle, Gary T.

    Copyright by John Arthur McLees, Jr. 2006 #12;Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water in Engineering The University of Texas at Austin May, 2006 #12;Vapor-Liquid Equilibrium of Monoethanolamine/Piperazine/Water games, and road trips that I am very excited to be staying here in Austin to watch him progress through

  14. Impact of Atmospheric Water Vapor on the Design of a Ku Band Geosynchronous SAR System

    Microsoft Academic Search

    Andrea Monti Guarnieri; Fabio Rocca; Antoni Broquetas Ibars

    2009-01-01

    We consider a geosynchronous Ku band system, and the defocusing effects due to the temporal and spatial variability of the atmospheric water vapor. Due to the very slow formation of the spatial chirp (minutes or even hours), the temporal change of the local water vapor content could be significant, thus preventing a correct image focusing and the formation of a

  15. Remote sensing of total precipitable water vapor in the near-IR over ocean glint

    Microsoft Academic Search

    Richard G. Kleidman; Yoram J. Kaufman; Bo-Cai Gao; Lorraine A. Remer; Vincent G. Brackett; Richard A. Ferrare; Edward V. Browell; Syed Ismail

    2000-01-01

    A method for remote sensing of total precipitable water vapor using water vapor absorption band at 0.94 mum was previously developed for continental regions. Here we apply a similar technique for ocean areas over the glint region. The glint, or oceanic specular reflection, has a high value of surface reflectance and thus, can work as well as or better than

  16. Geodesy by radio interferometry: Water vapor radiometry for estimation of the wet delay

    Microsoft Academic Search

    G. Elgered; J. L. Davis; T. A. Herring; I. I. Shapiro

    1991-01-01

    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

  17. Further Study of the Effect of Water Vapor on Slider Air Bearing

    Microsoft Academic Search

    Yansheng Ma; Bo Liu

    2009-01-01

    It has been proved that water vapor in moist air contributes to slider air-bearing pressure in a totally different way from dry air. It is a very good first order approximation to take a constant water vapor pressure inside and outside the interface. The simulated slider flying height and attitude in moist air are different from that in dry air

  18. Models of the atmospheric water vapor budget for the Texas HIPLEX area: by Steven Francis Williams.

    E-print Network

    Williams, Steven Francis

    1979-01-01

    be completely underst!. nd sn envirorm&ental w. '-er bu&iget des. . ribes the transports, distributio. . s, and supplies of water. vapor a sociated with various forr! of convective activity. Observatrorrs of diff "rences 'n the water vapor budget fr&r various...

  19. Diurnal variation in water vapor over North America and its implications for sampling errors in radiosonde humidity

    E-print Network

    Wang, Junhong

    ; 1655 Global Change: Water cycles (1836); 6969 Radio Science: Remote sensing; KEYWORDS: water vapor, diurnal cycle, GPS 1. Introduction [2] Water vapor plays a key role in atmospheric radiation and hydrological cycle. Observations of atmospheric water vapor are traditionally made through balloon

  20. Water, Vapor, and Salt Dynamics in a Hot Repository

    SciTech Connect

    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

    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)

  1. In situ measurements of water vapor in the Arctic winter lower stratosphere

    NASA Astrophysics Data System (ADS)

    Spackman, James Ryan

    The Harvard Lyman-alpha photofragment fluorescence hygrometer measured water vapor aboard the NASA ER-2 aircraft during the SAGE III Ozone Loss and Validation Experiment (SOLVE), based from Kiruna, Sweden (68°N, 20°E), during January--March 2000. In situ measurements of water vapor, CH4, and N2O, acquired during SOLVE, are used to examine (1) dehydration in the Arctic vortex and (2) transport into the lowermost stratosphere in the context of middle- and high-latitude ozone declines. Knowledge of the total hydrogen budget of the Arctic winter stratosphere is pertinent to understanding the processes of formation of polar stratospheric clouds (PSCs) and quantifying the reactive uptake coefficients of the relevant cold aerosols, factors determining how fast reservoir halogen species (i.e., ClONO2, HCl) are converted to active forms (i.e., ClO, ClOOCl). Although the data indicate only isolated dehydration and rehydration episodes along ER-2 flight tracks (i.e., between 400 and 470 K) in the vortex, the relationship between H2O and CH4 for all flights during SOLVE suggests that subtle, widespread dehydration occurred above the ER-2 flight tracks, consistent with meteorological reanalysis data. Isentropic transport from the tropics plays a major role in redistributing ozone and water vapor at middle and high latitudes. Analysis of tracer-tracer correlations of the observed quantities H2O + 2*CH 4 and N2O indicates that rapid, poleward isentropic transport from the lower tropical stratosphere coupled with diabatic descent between the subtropical jet and polar jet delivers very young air to the high-latitude lowermost stratosphere during winter, while descent from the vortex and subsequent transport to lower latitudes is very limited. No evidence of isentropic mixing from the upper tropical troposphere survives in the high-latitude lowermost stratosphere except below 350 K, where markedly higher water vapor mixing ratios indicate mixing from the extratropical troposphere. The balance of all of these transport processes poses dynamical and chemical consequences for ozone. Transport from the lower tropical stratosphere (1) exports ozone-poor air to midlatitudes and the subvortex region and (2) distributes seasonally variable water vapor to the middle- and high-latitude lower stratosphere, potentially enhancing halogen-catalyzed ozone destruction through heterogeneous processing.

  2. A New Raman Water Vapor Lidar Calibration Technique and Measurements in the Vicinity of Hurricane Bonnie

    NASA Technical Reports Server (NTRS)

    Evans, Keith D.; Demoz, Belay B.; Cadirola, Martin P.; Melfi, S. H.; Whiteman, David N.; Schwemmer, Geary K.; Starr, David OC.; Schmidlin, F. J.; Feltz, Wayne

    2000-01-01

    The NAcA/Goddard Space Flight Center Scanning Raman Lidar has made measurements of water vapor and aerosols for almost ten years. Calibration of the water vapor data has typically been performed by comparison with another water vapor sensor such as radiosondes. We present a new method for water vapor calibration that only requires low clouds, and surface pressure and temperature measurements. A sensitivity study was performed and the cloud base algorithm agrees with the radiosonde calibration to within 10- 15%. Knowledge of the true atmospheric lapse rate is required to obtain more accurate cloud base temperatures. Analysis of water vapor and aerosol measurements made in the vicinity of Hurricane Bonnie are discussed.

  3. Water vapor in the Martian atmosphere by SPICAM IR/Mars-Express

    NASA Astrophysics Data System (ADS)

    Trokhimovskiy, Alexander; Fedorova, Anna; Korablev, Oleg; Bertaux, Jean-Loup; Villard, Eric; Rodin, Alexander V.

    Introduction SPICAM experiment along with PFS and OMEGA spectrometers on Mars Express has a capability to sound the water vapor in the atmosphere. The results of H2O measurements have been intensively published during last years [1-6]. Here we present the new analysis of SPICAM IR water vapor measurements, covering two Martian years. The near-IR channel of SPICAM experiment on Mars Express spacecraft is a 800-g acousto-optic tunable filter (AOTF)-based spectrometer operating in the spectral range of 1-1.7 m with resolving power of 2000 [7, 8]. The nadir measurements of H2O in the 1.37-m spectral band is one of the main objectives of the experiment. Data treatment As compared with previous analysis of water vapor presented in [4] we used the spectroscopic database HITRAN2004 [9] instead of HITRAN 2000 and the most recent measurements of the water line-width broadening in CO2 atmosphere. Latest version HITRAN2008 doesn't have any meaningful changes in water vapour lines, which are used for retrievment. Martian Climate Database V4.2 [10] was adopted for modelling of synthetic spectra and a scenario based on TES MY24 was used. The spare model of SPICAM IR instrument was recalibrated in June 2007 in Reims, to analyze specifically the sensitivity to the H2O vapor band. According to laboratory measurements, a leakage from the AOTF is responsible up to 5 Radiative transfer modelling and results Sensitivity of retrieval to aerosol scattering and different vertical distributions of aerosol and water vapor was analyzed for H2O absorption band at 1.38 m and 2.56 m for different dust particles. Dependences of equivalent width of the H2O band on the water vapor abundance and aerosol optical depth for different vertical distribution of water vapor and aerosol optical depth are obtained. A number of orbits processed with "honest" aerosol account, in some cases difference to clear atmosphere approach is meaningful. Open questions for further processing are great demand in computer resources and uncertainty about Martian atmosphere octal depths. Right now we are using data from SPICAM UV channel and PFS instrument onboard Mars Express. Calculations of Martian atmospheric dust optical for different particle models properties are done as well to shift data from one wavelength to another For today SPICAM data from January 2004 to January 2010, i.e. three Martian years, is fully processed in aspect of water vapor retrievment in the assumption of clear atmosphere. The seasonal trend of water vapor obtained by SPICAM IR is consistent with TES results and disagrees with MAWD South pole maximum measurements. The maximum abundance is 50-55 pr. m at the North pole (during MY28 data are missing) and 13-16 pr.m at the South pole. The northern tropical maximum amounts to 11-14 pr m. The seasonal trend of water vapor obtained by SPICAM IR is consistent for MY27 with TES results [11]. The South Pole maximum for MY28 agrees well with the MAWD South Pole measurements in 1977 [12]. It assumes the same dust conditions and global dust storm happened at MY28 Ls 270 like during the MAWD observations. The maximum near 30-60S at Ls 260 relates to Hellas observations. Recent observations of water vapour distribution during the same period by CRISM spectrometer onboard Mars Reconnaissance Orbiter support these results [6] References [1] Fouchet, T., (2007), Icarus 190, 32-49. [2] Melchiorri, R. (2007), PSS 55, 333-342. [3] Encrenaz, Th. (2005), AA 441, L9-L12. [4] Fedorova, A. et al. (2006), JGR 111, DOI:10.1029/2006JE002695. [5] R. Melchiorri. et al. (2009), Icarus, Volume 201, Issue 1, May 2009, Pages 102-112. [6] Smith, M. et al. (2009), JGR 114, , DOI:10.1029/2008JE003288, 2009 [7] Bertaux, J.-L. et al. (2006), JGR 111, DOI:10.1029/2006JE002690. [8] Korablev, O. et al. (2006), JGR 111, DOI:10.1029/2006JE002696. [9] Rothman, L.S. et al. (2005), JQSRT, 96, 139-204. [10] Forget, F. et al. (2007), LPICo1353.3098F. [11] Smith, M., (2004), Icarus 167, 148-165. [12] Jakosky, B. M., and C. B. Farmer, (1982), J. Geophys. Res., 87, B4, 2999-3019

  4. Voxel-optimized regional water vapor tomography and comparison with radiosonde and numerical weather model

    NASA Astrophysics Data System (ADS)

    Chen, Biyan; Liu, Zhizhao

    2014-07-01

    Water vapor tomography has been developed as a powerful tool to model spatial and temporal distribution of atmospheric water vapor. Global navigation satellite systems (GNSS) water vapor tomography refers to the 3D structural construction of tropospheric water vapor using a large number of GNSS signals that penetrate the tomographic modeling area from different positions. The modeling area is usually discretized into a number of voxels. A major issue involved is that some voxels are not crossed by any GNSS signal rays, resulting in an undetermined solution to the tomographic system. To alleviate this problem, the number of voxels crossed by GNSS signal rays should be as large as possible. An important way to achieve this is to optimize the geographic distribution of tomographic voxels. We propose an approach to optimize voxel distribution in both vertical and horizontal domains. In the vertical domain, water vapor profiles derived from radiosonde data are exploited to identify the maximum height of tomography and the optimal vertical resolution. In the horizontal domain, the optimal horizontal distribution of voxels is obtained by searching the maximum number of ray-crossing voxels in both latitude and longitude directions. The water vapor tomography optimization procedures are implemented using GPS water vapor data from the Hong Kong Satellite Positioning Reference Station Network. The tomographic water vapor fields solved from the optimized tomographic voxels are evaluated using radiosonde data and a numerical weather prediction non-hydrostatic model (NHM) obtained for the Hong Kong station. The comparisons of tomographic integrated water vapor (IWV) with the radiosonde and NHM IWV show that RMS errors of their differences are 1.41 and 3.09 mm, respectively. Moreover, the tomographic water vapor density results are compared with those of radiosonde and NHM. The RMS error of the density differences between tomography and radiosonde data is 1.05 . For the comparison between tomography and NHM, an overall RMS error of is achieved.

  5. Measurements of daytime and upper tropospheric water vapor profiles by Raman lidar

    SciTech Connect

    Bisson, S.E.; Goldsmith, J.E.M.

    1995-03-01

    One of the most important atmospheric constituents needed for climate and meteorological studies is water vapor. Water vapor plays an important role in driving atmospheric circulations through latent heat release and in determining the earth`s radiation budget, both through its radiative effects (water vapor is the major greenhouse gas) and cloud formation. The vertical distribution of water vapor is particularly important because it not only determines convective stability but radiative effects are also strongly altitude dependent. At present, considerable controversy exists over the nature of the vertical redistribution of water vapor in a changing climate, and particularly the distribution of water vapor in the upper troposphere. Understanding upper tropospheric moistening processes such as deep convection are therefore of prime importance in addressing the water vapor feedback question. A powerful, proven technique for the continuous measurement of nighttime water vapor profiles (in clear skies or up to the lowest cloud level) with high spatial and temporal resolution is Raman lidar. As part of the U.S. Department of Energy`s (DOE) Atmospheric Radiation Measurement (ARM) program, a high performance dual field-of-view (fov), narrowband Raman lidar system capable of both daytime and nighttime operation has been developed. In this paper, the Sandia Raman lidar system is discussed along with its application to two problems of current interest: daytime tropospheric water vapor profile measurements and upper tropospheric water vapor. We present recent measurements of upper tropospheric moisture made at the DOE Cloud and Radiation Testbed site (CART) in Oklahoma. Recent daytime measurements are also presented.

  6. A feasibility study for the retrieval of the total column precipitable water vapor from satellite observations in the blue spectral range

    NASA Astrophysics Data System (ADS)

    Wagner, T.; Beirle, S.; Sihler, H.; Mies, K.

    2013-04-01

    We present a new algorithm for satellite retrievals of the atmospheric water vapor column in the blue spectral range. The water vapor absorption cross section in the blue spectral range is much weaker than in the red spectral range. Thus the detection limit and the uncertainty of individual observations is systematically larger than for retrievals at longer wavelengths. Nevertheless, water vapor retrievals in the blue spectral range have also several advantages: since the surface albedo in the blue spectral range is similar over land and ocean, water vapor retrievals are more consistent than for longer wavelengths. Compared to retrievals at longer wavelengths, over ocean the sensitivity for atmospheric layers close to the surface is higher due to the (typically 2 to 3 times) higher ocean albedo in the blue. Water vapor retrievals in the blue spectral range are also possible for satellite sensors, which do not measure at longer wavelengths of the visible spectral range like the Ozone Monitoring instrument (OMI). We investigated details of the water vapor retrieval in the blue spectral range based on radiative transfer simulations and observations from the Global Ozone Monitoring Experiment 2 (GOME-2) and OMI. It is demonstrated that it is possible to retrieve the atmospheric water vapor column density in the blue spectral range over most parts of the globe. The findings of our study are of importance also for future satellite missions like e.g. Sentinel 4 and 5.

  7. Gas Scavenging of Soluble and Insoluble Organic Vapors by Levitated Water Drops.

    NASA Astrophysics Data System (ADS)

    Seaver, Mark; Barrett, Amy

    1994-07-01

    Three-millimeter-diameter drops of water were levitated with a standing acoustic wave centered in the jet of a small wind tunnel and the volume changes as the drop evaporates in the presence of 1-propanol vapor were measured. The results are compared with a steady-state continuum evaporation model based on nonideal solution theory. Because the thermodynamic parameter for the 1-propanol-water system are well known, this system provides a test for our model. Good overall agreement between model and experiment results means that small discrepancies can be used to establish limits for dynamic effects. An immiscible liquids version of this model, which accounts for gas scavenging of methyl salicylate, is used to predict the amount of insoluble material scavenged by a drop of water evaporating to dryness. This model predicts that the volume of organic liquid left behind increases as the relative humidity approaches 100%.

  8. Millimeter-wave Radiometer for High Sensitivity Water Vapor Profiling in Arid Regions

    SciTech Connect

    Pazmany, Andrew

    2006-11-09

    Abstract - ProSensing Inc. has developed a G-band (183 GHz) water Vapor Radiometer (GVR) for long-term, unattended measurements of low concentrations of atmospheric water vapor and liquid water. Precipitable water vapor and liquid water path are estimated from zenith brightness temperatures measured from four double-sideband receiver channels, centered at 183.31 1, 3 and 7, and 14 GHz. A prototype ground-based version of the instrument was deployed at the DOE ARM program?s North Slope of Alaska site near Barrow AK in April 2005, where it collected data continuously for one year. A compact, airborne version of this instrument, packaged to operate from a standard 2-D PMS probe canister, has been tested on the ground and is scheduled for test flights in the summer of 2006. This paper presents design details, laboratory test results and examples of retrieved precipitable water vapor and liquid water path from measured brightness temperature data.

  9. Investigation of Organic Vapor Losses to Condensed Water Vapor in Tedlar® Bags Used for Exhaled-Breath Sampling

    Microsoft Academic Search

    William A. Groves; Edward T. Zellers

    1996-01-01

    This study evaluated the potential loss of organic vapors to condensed water in bags used for breath sampling. “Wet” test atmospheres were prepared by transferring nitrogen into 1-L Tedlar® bags and spiking with water and each of several organic solvents (methanol, acetone, 2-butanone, m-xylene, 1, 1, 1 trichloroethane, and perchloroethylene) to yield atmospheres representative of a 500-mL breath sample collected

  10. Internal Consistency of the NVAP Water Vapor Dataset

    NASA Technical Reports Server (NTRS)

    Suggs, Ronnie J.; Jedlovec, Gary J.; Arnold, James E. (Technical Monitor)

    2001-01-01

    The NVAP (NASA Water Vapor Project) dataset is a global dataset at 1 x 1 degree spatial resolution consisting of daily, pentad, and monthly atmospheric precipitable water (PW) products. The analysis blends measurements from the Television and Infrared Operational Satellite (TIROS) Operational Vertical Sounder (TOVS), the Special Sensor Microwave/Imager (SSM/I), and radiosonde observations into a daily collage of PW. The original dataset consisted of five years of data from 1988 to 1992. Recent updates have added three additional years (1993-1995) and incorporated procedural and algorithm changes from the original methodology. Since each of the PW sources (TOVS, SSM/I, and radiosonde) do not provide global coverage, each of these sources compliment one another by providing spatial coverage over regions and during times where the other is not available. For this type of spatial and temporal blending to be successful, each of the source components should have similar or compatible accuracies. If this is not the case, regional and time varying biases may be manifested in the NVAP dataset. This study examines the consistency of the NVAP source data by comparing daily collocated TOVS and SSM/I PW retrievals with collocated radiosonde PW observations. The daily PW intercomparisons are performed over the time period of the dataset and for various regions.

  11. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewski, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under-cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 Wm per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  12. Single frequency and wavelength stabilized near infrared laser source for water vapor DIAL remote sensing application

    NASA Astrophysics Data System (ADS)

    Chuang, Ti; Walters, Brooke; Shuman, Tim; Losee, Andrew; Schum, Tom; Puffenberger, Kent; Burnham, Ralph

    2015-02-01

    Fibertek has demonstrated a single frequency, wavelength stabilized near infrared laser transmitter for NASA airborne water vapor DIAL application. The application required a single-frequency laser transmitter operating at 935 nm near infrared (NIR) region of the water vapor absorption spectrum, capable of being wavelength seeded and locked to a reference laser source and being tuned at least 100 pm across the water absorption spectrum for DIAL on/off measurements. Fibertek is building a laser transmitter system based on the demonstrated results. The laser system will be deployed in a high altitude aircraft (ER-2 or UAV) to autonomously perform remote, long duration and high altitude water vapor measurements.

  13. Measurements of water vapor adsorption on the Geysers rocks

    SciTech Connect

    Gruszkiewicz, Miroslaw S.; Horita, Juske; Simonson, John M.; Mesmer, Robert E.

    1996-01-24

    The ORNL high temperature isopiestic apparatus was adapted for adsorption measurements. The quantity of water retained by rock samples taken from three different wells of The Geysers was measured at 150 °C and at 200 °C as a function of pressure in the range 0.00 ? p/p0 ? 0.98, where p0 is the saturated water vapor pressure. The rocks were crushed and sieved into three fractions of different grain sizes (with different specific surface areas). Both adsorption (increasing pressure) and desorption (decreasing pressure) runs were made in order to investigate the nature and extent of the hysteresis. Additionally, BET surface area analyses were performed by Porous Materials Inc. on the same rock samples using nitrogen or krypton adsorption measurements at 77 K. Specific surface areas and pore volumes were determined. These parameters are important in estimating water retention capability of a porous material. The same laboratory also determined the densities of the samples by helium pycnometry. Their results were then compared with our own density values obtained by measuring the effect of buoyancy in compressed argon. One of the goals of this project is to determine the dependence of the water retention capacity of the rocks as a function of temperature. The results show a significant dependence of the adsorption and desorption isotherms on the grain size of the sample. The increase in the amount of water retained with temperature observed previously (Shang et al., 1994a, 1994b, 1995) between 90 and 130°C for various reservoir rocks from The Geysers may be due to the contribution of slow chemical adsorption and may be dependent on the time allowed for equilibration. In contrast with the results of Shang et al. (1994a, 1994b, 1995), some closed and nearly closed hysteresis loops on the water adsorption/desorption isotherms (with closing points at p/p0 ? 0.6) were obtained in this study. In these cases the effects of activated processes were not present, and no increase in water adsorption with temperature was observed

  14. Correction technique for raman water vapor lidar signal dependent bias and suitability for water vapor trend monitoring in the upper troposphere

    NASA Astrophysics Data System (ADS)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L.; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; Jordan, A.; Vömel, H.

    2011-12-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE mobile laboratory in the MOHAVE-2009 campaign. In an appendix we also report on the performance of the corrected Vaisala RS92 radiosonde during the campaign. A new radiosonde based calibration algorithm is presented that reduces the influence of atmospheric variability on the derived calibration constant. The MOHAVE-2009 campaign permitted all Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated revealing that wet biases in upper tropospheric and lower stratospheric water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the data. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most resistant to additional noise sources. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC and elsewhere despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

  15. Production of long-term global water vapor and liquid water data set using ultra-fast methods to assimilate multi-satellite and radiosonde observations

    NASA Technical Reports Server (NTRS)

    Vonderhaar, T. H.; Reinke, Donald L.; Randel, David L.; Stephens, Graeme L.; Combs, Cynthia L.; Greenwald, Thomas J.; Ringerud, Mark A.; Wittmeyer, Ian L.

    1993-01-01

    During the next decade, many programs and experiments under the Global Energy and Water Cycle Experiment (GEWEX) will utilize present day and future data sets to improve our understanding of the role of moisture in climate, and its interaction with other variables such as clouds and radiation. An important element of GEWEX will be the GEWEX Water Vapor Project (GVaP), which will eventually initiate a routine, real-time assimilation of the highest quality, global water vapor data sets including information gained from future data collection systems, both ground and space based. The comprehensive global water vapor data set being produced by METSAT Inc. uses a combination of ground-based radiosonde data, and infrared and microwave satellite retrievals. This data is needed to provide the desired foundation from which future GEWEX-related research, such as GVaP, can build. The first year of this project was designed to use a combination of the best available atmospheric moisture data including: radiosonde (balloon/acft/rocket), HIRS/MSU (TOVS) retrievals, and SSM/I retrievals, to produce a one-year, global, high resolution data set of integrated column water vapor (precipitable water) with a horizontal resolution of 1 degree, and a temporal resolution of one day. The time period of this pilot product was to be det3ermined by the availability of all the input data sets. January 1988 through December 1988 were selected. In addition, a sample of vertically integrated liquid water content (LWC) was to be produced with the same temporal and spatial parameters. This sample was to be produced over ocean areas only. Three main steps are followed to produce a merged water vapor and liquid water product. Input data from Radiosondes, TOVS, and SSMI/I is quality checked in steps one and two. Processing is done in step two to generate individual total column water vapor and liquid water data sets. The third step, and final processing task, involves merging the individual output products to produce the integrated water vapor product. A final quality control is applied to the merged data sets.

  16. Electro-Osmosis and Water Uptake in Polymer Electrolytes in Equilibrium with Water Vapor at Low Temperatures

    Microsoft Academic Search

    Kevin G. Gallagher; Bryan S. Pivovar; Thomas F. Fuller

    2009-01-01

    Water uptake and electro-osmosis are investigated to improve the understanding and aid the modeling of water transport in proton-exchange membrane fuel cells (PEMFCs) below 0 C. Measurements of water sorption isotherms show a significant reduction in the water capacity of polymer electrolytes below 0 C. This reduced water content is attributed to the lower vapor pressure of ice compared to

  17. Variations of the glacio-marine air mass front in West Greenland through water vapor isotopes

    NASA Astrophysics Data System (ADS)

    Kopec, B. G.; Lauder, A. M.; Posmentier, E. S.; Feng, X.

    2012-12-01

    While the isotopic distribution of precipitation has been widely used for research in hydrology, paleoclimatology, and ecology for decades, intensive isotopic studies of atmospheric water vapor has only recently been made possible by spectral-based technology. New instrumentation based on this technology opens up many opportunities to investigate short-term atmospheric dynamics involving the water cycle and moisture transport. We deployed a Los Gatos Water Vapor Isotope Analyzer (WVIA) at Kangerlussuaq, Greenland from July 21 to August 15, and measured the water vapor concentration and its isotopic ratios continuously at 10s intervals. A Danish Meteorological Institute site is located about 1 km from the site of the deployment, and meteorological data is collected at 30 min intervals. During the observation period, the vapor concentration of the ambient air ranges from 5608.4 to 11189.4 ppm; dD and d18O range from -254.5 to -177.7 ‰ and -34.2 to -23.2 ‰, respectively. The vapor content (dew point) and the isotopic ratios are both strongly controlled by the wind direction. The easterly winds are associated with dry, isotopically depleted air masses formed over the glacier, while westerly winds are associated with moist and isotopically enriched air masses from the marine/fjord surface. This region typically experiences katabatic winds off of the ice sheet to the east. However, during some afternoons, the wind shifts 180 degrees, blowing off the fjord to the west. This wind switch marks the onset of a sea breeze, and significant isotopic enrichment results. Enrichment in deuterium is up to 60 ‰ with a mean of 15‰, and oxygen-18 is enriched by 3‰ on average and up to 8 ‰. Other afternoons have no change in wind, and only small changes in humidity and vapor isotopic ratios. The humidity and isotopic variations suggest the local atmosphere circulation is dominated by relatively high-pressure systems above the cold glaciers and cool sea surface, and diurnal pressure variations above the relatively warmer land surface in between. During the day as the land is heated, the katabatic wind converges with the sea breeze, producing a front normally over the fjord. On the former type of afternoons, when a sea breeze occurs, the front moves eastward off the fjord, crossing the land and the observation sites in Kangerlussuaq; on the latter afternoons the front remains over the fjord, probably moving east but not far enough to reach the land and Kangerlussuaq, and has no effect on the observation site. The data also show that in addition to this local circulation pattern, the area is influenced by synoptic storm systems as well. A low-pressure system passed slowly across the region over the first 9 days of the observation period. The effects are seen as it interferes with the more regular diurnal cycle of the local circulation described above. In addition to this significant part of the cycle, the effects of lake water evaporation and landscape evapotranspiration is seen in the diurnal cycle. This can be seen on days when the wind direction did not shift in the afternoon, but the dew point and isotopic compositions became slightly higher. This is consistent with moisture contribution from lake evaporation, which is expected to be enriched in both oxygen-18 and deuterium compared to the ambient atmospheric water vapor.

  18. Validation of a new prototype water vapor retrieval for the UARS Microwave Limb Sounder

    NASA Astrophysics Data System (ADS)

    Pumphrey, Hugh C.

    1999-04-01

    The UARS Microwave Limb Sounder (MLS) measured water vapor in the middle atmosphere between September 1991 and April 1993. The current version of the data, version 4, and its predecessor, version 3, have been used in many scientific studies. As part of the process of developing the next version of UARS MLS data, a new prototype retrieval for the stratosphere/mesosphere water vapor product was developed at the University of Edinburgh. The main improvements made were (1) corrections for systematic errors and (2) doubling of the vertical resolution of the retrieval grid. Initial results were sufficiently encouraging that the code was used to produce data for all UARS days on which the MLS 183 GHz radiometer was operational. This paper describes these data and examines their quality. Comparisons are made with the available correlative data and it emerges that the prototype agrees better with the correlative data than does version 4. Agreement with frost point hygrometers is excellent in the lower stratosphere and agreement with a ground-based microwave is satisfactory in the upper stratosphere and mesosphere. Agreement with two solar occultation instruments, Atmospheric Trace Molecular Spectroscopy Experiment (ATMOS) and Halogen Occultation Experiment (HALOE), is better than it was for earlier MLS versions but the prototype data are uniformly drier than both of these instruments. We compare the data with version 4, showing several features which are more clearly visible in the new prototype. These include seasonal cycles in the upper mesosphere and equatorial lower stratosphere.

  19. LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Saharan Air Layers and Tropical Disturbances

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Ferrare, Richard; Browell, Edward; Kooi, Susan; Notari, Anthony; Butler, Carolyn; Burton, Sharon; Fenn, Marta; Krishnamurti, T. N.; Dunion, Jason; Heymsfield, Gerry; Anderson, Bruce

    2008-01-01

    LASE (Lidar Atmospheric Sensing Experiment) onboard the NASA DC-8 was used to measure high resolution profiles of water vapor and aerosols, and cloud distributions in 14 flights over the eastern Atlantic region during the NAMMA (NASA African Monsoon Multidisciplinary Analyses) field experiment, which was conducted from August 15 to September 12, 2006. These measurements were made in conjunction with flights designed to study African Easterly Waves (AEW), Tropical Disturbances (TD), and Saharan Aerosol Layers (SALs) as well as flights performed in clear air and convective regions. As a consequence of their unique radiative properties and dynamics, SAL layers have a significant influence in the development of organized convection associated with TD. Interactions of the SAL with tropical air during early stages of the development of TD were observed. These LASE measurements represent the first simultaneous water vapor and aerosol lidar measurements to study the SAL and its impact on TDs and hurricanes. Seven AEWs were studied and four of these evolved into tropical storms and three did not. Three out of the four tropical storms evolved into hurricanes.

  20. AIR HUMIDITY WITHIN BOUNDARYLAYER OF A TRANSPIRING LEAF I. RELATIONSHIP BETWEEN TRANSPIRATION AND WATER VAPOR DENSITY AT LEAF SURFACE

    Microsoft Academic Search

    M. KITANO; H. EGUCHI

    KITANO M. and EGUCHI H. Air humidity within boundary layer ofa transpiring leaf. 1. Relationship between transpiration and water vapor density at leafsurface. BIOTRONICS 16, 39-45, 1987. A simple system for on-line measurement of water vapor density within leaf boundary layer was developed, and water vapor density (WBO) at the cucumber leaf surface was analyzed in relation to transpiration rate

  1. An Algorithm for Retrieving Water Vapor Profiles in Clear and Cloudy Atmospheres from 183 GHz Radiometric Measurements: Simulation Studies

    Microsoft Academic Search

    Thomas T. Wilheit

    1990-01-01

    The latent heat represented by atmospheric water vapor is extremely important to the energetics of the Earth system. Future satellite (NOAA and DMSP) will carry microwave radiometers designed to measure the profile of water vapor globally. The problem of retrieving water vapor from the measurements is highly nonlinear even in clear atmospheres and the addition of clouds only makes it

  2. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 35, NO. 2, MARCH 1997 203 Retrieval of Tropospheric Water Vapor Scale

    E-print Network

    Ruf, Christopher

    near the strong 183.3 GHz water vapor line are also capable of profiling water vapor. Retrieval is significantly degraded. Numerical simulations of the retrieval of relative humidity profiles at 183 GHz also affected by clouds and wind. Microwave radiometers which use the weak 22.2 GHz water vapor line are well

  3. Diurnal cycle of water vapor as documented by a dense GPS network in a coastal area during

    E-print Network

    Boyer, Edmond

    Diurnal cycle of water vapor as documented by a dense GPS network in a coastal area during ESCOMPTE used for the analysis of the diurnal cycle of water vapor over Marseille, France during the second to the advection of marine moist air by these sea breeze circulations. However, the diurnal cycle of water vapor

  4. Interaction of Water Vapor with the Surfaces of Imidazolium-Based Ionic Liquid Nanoparticles and Thin Films

    E-print Network

    Nizkorodov, Sergey

    Interaction of Water Vapor with the Surfaces of Imidazolium-Based Ionic Liquid Nanoparticles techniques, water vapor's interaction with aerosolized nanoparticles and thin films of [C2MIM][Cl] and [C2MIM. The particles' small size allows true IL-water vapor equilibrium achieved quickly. Growth curves for both ILs

  5. The effect of water vapor on the oxidation behavior of Ni–Pt–Al coatings and alloys

    Microsoft Academic Search

    Bruce A Pint; James A Haynes; Ying Zhang; Karren Leslie More; Ian G Wright

    2006-01-01

    Turbines fired with hydrogen or syngas from coal gasification will have significantly higher water vapor contents in the combustion gas than natural gas fired turbines. The effect of increased water vapor on alumina-forming coatings and model alloys was investigated at 1100 °C in furnace cyclic testing. Increasing the water vapor content from 10% to 50 vol.% increased the amount of scale spallation

  6. ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 24, NO. 3, 2007, 509526 Variational Assimilation of GPS Precipitable Water Vapor and

    E-print Network

    weightings and the control of spurious gravity waves. Key words: GPS, precipitable water vapor, four Precipitable Water Vapor and Hourly Rainfall Observations for a Meso- Scale Heavy Precipitation Event During of the precipitable water vapor (PWV) from delayed signals transmitted by GPS satellites, which can be assimilated

  7. Seasonal Trends in Stratospheric Water Vapor as Derived from SAGE II Data

    NASA Technical Reports Server (NTRS)

    Roell, Marilee M.; Fu, Rong

    2008-01-01

    Published analysis of HALOE and Boulder balloon measurements of water vapor have shown conflicting trends in stratospheric water vapor for the periods of 1981 through 2005. Analysis of the SAGE II monthly mean water vapor data filtered for large aerosol events for time periods from 1985-1991, 1995-1999, and 2000-2005 have shown a globally decreasing water vapor trend at 17.5km. Seasonal analysis for these three time periods show a decreasing trend in water vapor at 17.5km for the winter and spring seasons. The summer and autumn seasonal analysis show a decreasing trend from 1985-2005, however, there is a increasing trend in water vapor at 17.5km for these seasons during 1995-2005. Latitude vs height seasonal analysis show a decreasing trend in the lower stratosphere between 20S - 20N for the autumn season, while at the latitudes of 30-50S and 30-50N there is an increasing trend in water vapor at heights up to 15km for that season. Comparison with regions of monsoon activity (Asian and North American) show that the Asian monsoon region had some effect on the lower stratospheric moistening in 1995-1999, however, for the time period of 2000-2005, there was no change in the global trend analysis due to either monsoon region. This may be due to the limitations of the SAGE II data from 2000-2005.

  8. A novel membrane device for the removal of water vapor and water droplets from air

    NASA Technical Reports Server (NTRS)

    Ray, Rod; Newbold, David D.; Mccray, Scott B.; Friesen, Dwayne T.; Kliss, Mark

    1992-01-01

    One of the key challenges facing NASA engineers is the development of systems for separating liquids and gases in microgravity environments. In this paper, a novel membrane-based phase separator is described. This device, known as a water recovery heat exchanger (WRHEX), overcomes the inherent deficiencies of current phase-separation technology. Specifically, the WRHEX cools and removes water vapor or water droplets from feed-air streams without the use of a vacuum or centrifugal force. As is shown in this paper, only a low-power air blower and a small stream of recirculated cool water is required for WRHEX operation. This paper presents the results of tests using this novel membrane device over a wide range of operating conditions. The data show that the WRHEX produces a dry air stream containing no entrained or liquid water - even when the feed air contains water droplets or mist. An analysis of the operation of the WRHEX is presented.

  9. Case Studies of Water Vapor and Surface Liquid Water from AVIRIS Data Measured Over Denver, CO and Death Valley, CA

    NASA Technical Reports Server (NTRS)

    Gao, B.-C.; Kierein-Young, K. S.; Goetz, A. F. H.; Westwater, E. R.; Stankov, B. B.; Birkenheuer, D.

    1991-01-01

    High spatial resolution column atmospheric water vapor amounts and equivalent liquid water thicknesses of surface targets are retrieved from spectral data collected by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS). The retrievals are made using a nonlinear least squares curve fitting technique. Two case studies from AVIRIS data acquired over Denver-Platteville area, Colorado and over Death Valley, California are presented. The column water vapor values derived from AVIRIS data over the Denver-Platteville area are compared with those obtained from radiosondes, ground level upward-looking microwave radiometers, and geostationary satellite measurements. The column water vapor image shows spatial variation patterns related to the passage of a weather front system. The column water vapor amounts derived from AVIRIS data over Death Valley decrease with increasing surface elevation. The derived liquid water image clearly shows surface drainage patterns.

  10. Water Vapor Measurements by Howard University Raman Lidar during the WAVES 2006 Campaign

    NASA Technical Reports Server (NTRS)

    Adam, M.; Demoz, B. B.; Whiteman, D. N.; Venable, D. D.; Joseph E.; Gambacorta, A.; Wei, J.; Shephard, M. W.; Miloshevich, L. M.; Barnet, C. D.; Herman, R. L.; Fitzgibbon, J.; Connell, R.

    2009-01-01

    Retrieval of water vapor mixing ratio using the Howard University Raman Lidar is presented with emphasis on three aspects: i) performance of the lidar against collocated radiosondes and Raman lidar, ii) investigation of the atmospheric state variables when poor agreement between lidar and radiosondes values occurred and iii) a comparison with satellite-based measurements. The measurements were acquired during the Water Vapor Validation Experiment Sondes/Satellites 2006 field campaign. Ensemble averaging of water vapor mixing ratio data from ten night-time comparisons with Vaisala RS92 radiosondes shows on average an agreement within 10 % up to approx. 8 km. A similar analysis of lidar-to-lidar data of over 700 profiles revealed an agreement to within 20 % over the first 7 km (10 % below 4 km). A grid analysis, defined in the temperature - relative humidity space, was developed to characterize the lidar - radiosonde agreement and quantitatively localizes regions of strong and weak correlations as a function of altitude, temperature or relative humidity. Three main regions of weak correlation emerge: i) regions of low relative humidity and low temperature, ii) moderate relative humidity at low temperatures and iii) low relative humidity at moderate temperatures. Comparison of Atmospheric InfraRed Sounder and Tropospheric Emission Sounder satellites retrievals of moisture with that of Howard University Raman Lidar showed a general agreement in the trend but the formers miss a lot of the details in atmospheric structure due to their low resolution. A relative difference of about 20 % is usually found between lidar and satellites measurements.

  11. Impact of modifying the longwave water vapor continuum absorption model on community Earth system model simulations

    NASA Astrophysics Data System (ADS)

    Turner, D. D.; Merrelli, A.; Vimont, D.; Mlawer, E. J.

    2012-02-01

    The far-infrared (wavelengths longer than 17?m) has been shown to be extremely important for radiative processes in the earth's atmosphere. The strength of the water vapor continuum absorption in this spectral region has largely been predicted using observations at other wavelengths that have been extrapolated using semiempirical approaches such as the Clough-Kneizys-Davies (CKD) family of models. Recent field experiments using new far-infrared instrumentation have supported a factor of 2 decrease in the modeled strength of the foreign continuum at 50?m and a factor of 1.5 increase in the self-continuum at 24?m in the Clough-Kneizys-Davies continuum model (CKD v2.4); these changes are incorporated in the Mlawer-Tobin-CKD continuum model (MT_CKD v2.4). The water vapor continuum in the Community Earth System Model (CESM v1.0) was modified to use the newer model, and the impacts of this change were investigated by comparing output from the original and modified CESM for 20 year integrations with prescribed sea surface temperatures. The change results in an increase in the net upward longwave flux of order 0.5 W m-2between 300 and 400 mb, and a decrease in this flux of about the same magnitude for altitudes below 600 mb. The radiative impact results in a small but statistically significant change in the mean temperature and humidity fields, and also a slight decrease (order 0.5%) of high-cloud amount. The change in the cloud amount modified the longwave cloud radiative forcing, which partially offset the radiative heating caused by the change in the water vapor continuum absorption model.

  12. A New Criterion to Evaluate Water Vapor Interference in Protein Secondary Structural Analysis by FTIR Spectroscopy

    PubMed Central

    Zou, Ye; Ma, Gang

    2014-01-01

    Second derivative and Fourier self-deconvolution (FSD) are two commonly used techniques to resolve the overlapped component peaks from the often featureless amide I band in Fourier transform infrared (FTIR) curve-fitting approach for protein secondary structural analysis. Yet, the reliability of these two techniques is greatly affected by the omnipresent water vapor in the atmosphere. Several criteria are currently in use as quality controls to ensure the protein absorption spectrum is negligibly affected by water vapor interference. In this study, through a second derivative study of liquid water, we first argue that the previously established criteria cannot guarantee a reliable evaluation of water vapor interference due to a phenomenon that we refer to as sample’s absorbance-dependent water vapor interference. Then, through a comparative study of protein and liquid water, we show that a protein absorption spectrum can still be significantly affected by water vapor interference even though it satisfies the established criteria. At last, we propose to use the comparison between the second derivative spectra of protein and liquid water as a new criterion to better evaluate water vapor interference for more reliable second derivative and FSD treatments on the protein amide I band. PMID:24901531

  13. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1984-01-01

    Heat transfer coefficients were measured using both dry and humid air in the same forced convection cooling scheme and were compared using appropriate nondimensional parameters (Nusselt, Prandtl and Reynolds numbers). A forced convection scheme with a complex flow field, two dimensional arrays of circular jets with crossflow, was utilized with humidity ratios (mass ratio of water vapor to air) up to 0.23. The dynamic viscosity, thermal conductivity and specific heat of air, steam and air/steam mixtures are examined. Methods for determining gaseous mixture properties from the properties of their pure components are reviewed as well as methods for determining these properties with good confidence. The need for more experimentally determined property data for humid air is discussed. It is concluded that dimensionless forms of forced convection heat transfer data and empirical correlations based on measurements with dry air may be applied to conditions involving humid air with the same confidence as for the dry air case itself, provided that the thermophysical properties of the humid air mixtures are known with the same confidence as their dry air counterparts.

  14. Measurements of lower stratospheric/upper tropospheric water vapor by the SAGE II instrument

    NASA Technical Reports Server (NTRS)

    Larsen, J. C.; Mcmaster, L. R.; Mccormick, M. P.; Chu, W. P.

    1986-01-01

    Preliminary, unvalidated data are discussed from early measurements of water vapor profiles in the upper troposphere/lower stratosphere by means of SAGE II satellite sensors. Zonal means for April 1985 are discussed and compared with previous, separate data sets for water vapor profiles for the 100 mbar and 300 mbar levels determined from space-based IR and rawinsonde data. Techniques employed to correct for noisy measurements due to the presence of clouds in the SAGE II scenes are described, noting the slant path transmission methods applied to generate the water vapor profiles.

  15. Upper tropospheric water vapor: A field campaign of two Raman lidars, Airborne hygrometers, and Radiosondes

    NASA Technical Reports Server (NTRS)

    Melfi, S. Harvey; Turner, Dave; Evans, Keith; Whiteman, Dave; Schwemmer, Geary; Ferrare, Richard

    1998-01-01

    Water vapor in the atmosphere plays an important role in radiative transfer and the process of radiative balance so critical for understanding global change. It is the principal ingredient in cloud formation, one of the most difficult atmospheric processes to model, and the most variable component of the Earth-atmosphere albedo. And as a free molecule, it is the most active infrared absorber and emitter, thus, the most important greenhouse gas. The radiative impact of water vapor is important at all levels of the atmosphere. Even though moisture decreases by several orders-of-magnitude from the Earth's surface to the tropopause, recent research has shown that, from a radiative standpoint, a small percentage change in water vapor at any level is nearly equivalent. Therefore accurate and precise measurements of this important atmospheric constituent are needed at all levels to evaluate the full radiative impact. The need for improved measurements in the upper troposphere is particularly important because of the generally hostile (very dry and cold) conditions encountered. Because of the importance of water vapor to the understanding of radiative transfer, the Department of Energy's Atmospheric Radiation Measurements (ARM) program initiated a series of measurement campaigns at the Cloud And Radiation Testbed (CART) site in Oklahoma, especially focused on atmospheric water vapor. Three water vapor intensive observation period (water vapor IOP) campaigns were planned. Two of the water vapor IOP campaigns have been completed: the first IOP was held during the fall of 1996 with a focus on boundary layer water vapor measurements, and the second was conducted during the fall of 1997 with a focus on both boundary layer moisture e and moisture in the upper troposphere. This paper presents a review of the intercomparisons of water vapor measurements in the upper troposphere aquired during the second water vapor IOP. Data to be presented include water vapor measurements ements from: two Raman Lidars, the NASA Goddard Scanning Raman Lidar (SRL) and the CART Raman Lidar (CARL), a number of Vaisala radiosondes launched during the IOP campaign, and a dew point hygrometer flown on the University of North Dakota Cessna Citation Aircraft.

  16. Effects of ambient water vapor pressure and temperature on evaporative water loss in Peromyscus maniculatus and Mus musculus

    Microsoft Academic Search

    Richard M. Edwards; Howard Haines

    1978-01-01

    Summary  The effects of ambient water vapor pressure (VP) and temperature on evaporative water loss (EWL) from the head and trunk ofPeromyscus maniculatus andMus musculus were measured with dew point hygrometry. At a given ambient temperature both head and trunk EWL were directly proportional to the water vapor pressure deficit. Cutaneous EWL in both species was directly related to the difference

  17. Author's personal copy Continuous measurement of water vapor D/H and

    E-print Network

    Lee, Xuhui

    the difference in the relative importance of the equilibrium and kinetic fractionation effects between HDO and H2 of liquid/vapor equilibrium, the equilibrium fractionation effect of D/H is 8.3­9.6 times higher thanAuthor's personal copy Continuous measurement of water vapor D/H and 18 O/16 O isotope ratios

  18. Kinetic Requirements for the Measurement of Mesospheric Water Vapor at 6.8 (microns) under Non-LTE Conditions

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Mlynczak, Martin G.; Lopez-Puertas, Manuel; Russell, James M., III

    1999-01-01

    We present accuracy requirements for specific kinetic parameters used to calculate the populations and vibrational temperatures of the H2O(010) and H2O(020) states in the terrestrial mesosphere. The requirements are based on rigorous simulations of the retrieval of mesospheric water vapor profiles from measurements of water vapor infrared emission made by limb scanning instruments on orbiting satellites. Major improvements in the rate constants that describe vibration-to- vibration exchange between the H2O(010) and 02(1) states are required in addition to improved specification of the rate of quenching Of O2(1) by atomic oxygen (0). It is also necessary to more accurately determine the yield of vibrationally excited O2(l) resulting from ozone photolysis. A contemporary measurement of the rate of quenching of H2O(010) by N2 and O2 is also desirable. These rates are either highly uncertain or have never before been measured at atmospheric temperatures. The suggested improvements are necessary for the interpretation of water vapor emission measurements at 6.8 microns to be made from a new spaceflight experiment in less than 2 years. The approach to retrieving water vapor under non-LTE conditions is also presented.

  19. Retrieval of clear sky moisture profiles using the 183 GHz water vapor line

    NASA Technical Reports Server (NTRS)

    Kakar, R. K.

    1983-01-01

    A technique for retrieving vertical moisture profiles from downlooking radiometric measurements of atmospheric radiation near the 183 GHz water vapor line is described. A simulation experiment utilizing this retrieval technique and temperature and moisture profiles from tropical radiosonde stations has been carried out. Assuming the atmospheric temperature profile is known to 2 K rms (state-of-the-art with present remote sensors) and the instrument noise is 1-2 K rms brightness temperature (achievable with current technology), the humidity between the 700 and 1000 mb pressure levels was retrieved to within about 20 percent of true value over ocean and within about 45 percent of true value over land. The precipitable water content was retrieved to within about 10 percent rms of true value over the ocean and within about 45 percent rms of true value over land.

  20. Distribution of binding energies of a water molecule in the water liquid-vapor interface

    SciTech Connect

    Chempath, Shaji [Los Alamos National Laboratory; Pratt, Lawrence R [TULANE UNIV

    2008-01-01

    Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

  1. Twenty-Four-Hour Raman Lidar Water Vapor Measurements During the Atmospheric Radiation Measurement Program's 1996 and 1997 Water Vapor Intensive Observation Periods

    SciTech Connect

    Turner, David D.; Goldsmith, JE M.

    1999-08-01

    Prior to the Atmospheric Radiation Measurement program's first water vapor intensive observation period (WVIOP) at the Cloud and Radiation Testbed site near Lamont, Oklahoma, an automated 24-h Raman lidar was delivered to the site. This instrument, which makes high-resolution measurements of water vapor both spatially and temporally, is capable of making these measurements with no operator interaction (other than initial startup) for days at a time. Water vapor measurements collected during the 1996 and 1997 WVIOPs are discussed here, illustrating both the nighttime and daytime capabilities of this system. System characteristics, calibration issues, and techniques are presented. Finally, detailed intercomparisons of the lidar's data with those from a microwave radiometer, radiosondes, an instrumented tower, a chilled mirror flown on both a tethersonde and a kite, and measurements from aircraft are shown and discussed, highlighting the accuracy and stability of this system for both nighttime and daytime measurements.

  2. Interannual variation of water isotopologues at Vostok indicates a contribution from stratospheric water vapor

    PubMed Central

    Winkler, Renato; Landais, Amaelle; Risi, Camille; Baroni, Melanie; Ekaykin, Alexey; Jouzel, Jean; Petit, Jean Robert; Prie, Frederic; Minster, Benedicte; Falourd, Sonia

    2013-01-01

    Combined measurements of water isotopologues of a snow pit at Vostok over the past 60 y reveal a unique signature that cannot be explained only by climatic features as usually done. Comparisons of the data using a general circulation model and a simpler isotopic distillation model reveal a stratospheric signature in the 17O-excess record at Vostok. Our data and theoretical considerations indicate that mass-independent fractionation imprints the isotopic signature of stratospheric water vapor, which may allow for a distinction between stratospheric and tropospheric influences at remote East Antarctic sites. PMID:23798406

  3. Hydrogen Isotope Compositions and Variability in Atmospheric Water Vapor, Evapotranspirated Water, and Hydrometeoric Water in Central New Mexico.

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    The hydrogen isotope composition (?D) of atmospheric water vapor has been semi-continuously measured since April 2005 at ground level and within the boundary layer over Albuquerque, New Mexico. Water vapor has been compared with concurrently collected hydrometeoric water, evaporated water from local soil, and transpired water from local plants. Ground-level air has been collected ~ 3 times a day while periodically (every 1 to 2 weeks) air has been collected in a light aircraft throughout and above the boundary layer at altitude intervals of ~1000 ft. Between April and August, ground-level water vapor ?D ranges from -250‰ to -50‰. Variability of ?D in ground-level water vapor occurs on at least three different time scales. A diurnal cycle of ~15‰ variation exists throughout much of the record. Larger variations, up to 100‰, occur on time scales that range from a few hours to a few days and are thought to be associated with weather fluctuations. A seasonal trend toward isotopically heavier summer values has also been observed, and the amplitude of short-term ?D variations is smaller in summer. From April to June, the ?D ranges from -250‰ to -50‰, with an average of ~ -150‰. For the months of July and August, ?D ranges from -180‰ to -90‰ with an average of ~ -120‰. Precipitation, while infrequent, also becomes isotopically heavier and less variable in the summer. Dew point and ?D are highly correlated during June ((?(?D)/(?(dew point °C)) = 7.7; r2 = 0.76) but little to no correlation exists in April (r2 = 0.11 ) and August (r2 = 0.01). The ?D values of transpired water from local Juniper and Sage are between ~ -20‰ to ~ -50‰; local evaporation from soil has ?D between ~ -90‰ and ~ -110‰. Neither plants nor soil have shown significant changes in water vapor composition between June (dry season) and August (wet season). Our currently favored model for the observed ground-level variation in water vapor ?D is one of a nearly constant contribution from plants and soil with a variable atmospheric contribution. Atmospheric ?D exhibits pronounced variability associated with fluctuations in airmass trajectories and vertical motion as documented by local winds and the varying structure of the vertical boundary layer profiles.

  4. Quantifying consistency and biases between aircraft, balloon and remote sensing measurements of UT/LS water vapor during the WB-57 NASA MACPEX mission

    NASA Astrophysics Data System (ADS)

    Gao, R.; Rollins, A.; Thornberry, T. D.; Hall, E.; Jordan, A.; Hurst, D. F.; Smith, J. B.; Sargent, M. R.; Fahey, D. W.

    2011-12-01

    Mixing ratios of water vapor in Earth's upper troposphere and lower stratosphere (UT/LS) are low (< 10 ppmv), yet water in this region is a significant driver of climate. Significant discrepancies have repeatedly been observed between multiple high precision measurements of water vapor at these low values in the UT/LS, leading to uncertainty in the absolute value of the direct radiative forcing from stratospheric water vapor. During the NASA Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) mission in March and April of 2011, measurements of water vapor in the UT/LS were made using the NOAA chemical ionization mass spectrometer (CIMS) and Harvard Lyman-? water vapor (HWV) instruments integrated on the NASA WB-57 based out of Ellington Field, TX. This was the first aircraft deployment of the CIMS instrument configured to measure water vapor. The CIMS carried a novel in situ calibration system using two independent water vapor standards that were in excellent agreement throughout the campaign. CIMS was also in excellent agreement with HWV, which operates and is calibrated using fundamentally different principles. The redundant and independent calibration systems of CIMS and HWV afford new confidence in the accuracy of these aircraft measurements. We compare these aircraft measurements of water vapor to those made with the MLS instrument on the AURA satellite, and to frost point balloon borne (NOAA FPH and CFH) measurements coordinated with the WB-57 descents from the LS. A persistent bias of 0.7 ppmv is observed between the frost point and aircraft measurements in the 3 to 10 ppmv range, with frost point being lower. The MLS measurements are less precise, but generally fall between the balloon and aircraft measurements in the LS. These measurements renew interest in comparisons in the tropics where even lower mixing ratios and higher saturations with respect to ice are encountered.

  5. Crystal Growth by Physical Vapor Transport: Experiments and Simulation Dynamics

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Worlikar, A.; Su, Ching-Hua; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Crystal growth from the vapor phase has various advantages over melt growth. The main advantage is from a lower processing temperature, which makes the process more amenable in instances where the melting temperature of the crystal is high. Other benefits stem from the inherent purification mechanism in the process due to differences in the vapor pressures of the native elements and impurities, and the enhanced interfacial morphological stability during the growth process. Further, the implementation of PVT growth in closed ampoules affords experimental simplicity with minimal needs for complex process control, which makes it an ideal candidate for space investigations in systems where gravity tends to have undesirable effects on the growth process. Bulk growth of wide band gap II-VI semiconductors by PVT has been developed and refined over the past several years at NASA MSFC. A new modeling approach for PVT has also been recently formulated and its validation and testing is the main objective of this work.

  6. Temperature sensitivity of differential absorption lidar measurements of water vapor in the 720-nm region

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Ismail, Syed; Grossmann, Benoist E.

    1991-01-01

    Recently measured properties of water vapor (H2O) absorption lines have been used in calculations to evalute the temperature sensitivity of differential absorption lidar (Dial) H2O measurements. This paper estimates the temperature sensitivity of H2O lines in the 717-733-nm region for both H2O mixing ratio and number density measurements, and discusses the influence of the H2O line ground state energies E-double-prime, the H2O absorption linewidths, the linewidth temperature dependence parameter, and the atmospheric temperature and pressure variations with altitude and location on the temperature sensitivity calculations. Line parameters and temperature sensitivity calculations for 67 H2O lines in the 720-nm band are given which can be directly used in field experiments. Water vapor lines with E-double-prime values in the 100-300/cm range were found to be optimum for Dial measurements of H2O number densities, while E-double-prime values in the 250-500/cm range were found to be optimum for H2O mixing ratio measurements.

  7. High-sensitive measurement of water vapor: shot-noise level performance via a noise canceller.

    PubMed

    Wang, Qiang; Chang, Jun; Zhu, Cunguang; Liu, Yongning; Lv, Guangping; Wang, Fupeng; Liu, Xiangzhi; Wang, Zongliang

    2013-02-10

    Taking advantages of distributed feedback laser diode a technique is described to achieve high-sensitive measurement for water vapor concentration. This technique, with a modified balanced ratio metric detection system, has improved the accuracy of measured absorption spectrum by two main aspects. Improvement by matching equivalent conductivity of signal or reference photo detector (PD) is presented, and with the additional matched resistance suppression for the power variation in the signal-beam has been improved from 53 to 88 dB. The importance of integrating amplifier bandwidth design from the circuit to the measured absorption spectrum has been demonstrated in our experiment. For a scan rate of 32 Hz with an optimal corresponding bandwidth of 15.9 kHz, the absorption spectrum is well described by Voigt profile, with a difference of 1% at an atmosphere pressure of 1 atm and a room temperature of 296 K. With the application of averaging and filtering, absorption sensitivity of 1.093×10(-6) for water vapor at 1368.597 nm has been demonstrated, and the corresponding concentration is 71.8 ppb in just a 10 cm path length. PMID:23400072

  8. Time-dependent response of a charcoal bed to radon and water vapor in flowing air

    SciTech Connect

    Henkel, J.A.; Fentiman, A.W.; Blue, T.E. [Ohio State Univ., Columbus, OH (United States)

    1995-12-31

    Extremely high airborne concentrations of radon gas may be encountered during the remediation of uranium mill tailings storage facilities. Radon is also a constituent of the off-gas of mill-tailing vitrification. An effective way to remove radon from either gas is to pass the gas through a packed bed containing activated charcoal. Measurements of radon concentrations in the environment using charcoal canisters were first described by George. Canisters similar to those used by George in his first experiments have become the U.S. Environmental Protection Agency`s (EPA`s) standard for measuring environmental radon and were described in the EPA protocol for environmental radon measurement. The dynamic behavior of EPA charcoal canisters has been previously described with a mathematical model for the kinetics of radon gas adsorption in air in the presence of water vapor. This model for charcoal canisters has been extended to large charcoal beds with flowing air containing radon and water vapor. The mathematical model for large charcoal beds can be used to evaluate proposed bed designs or to model existing beds. Parameters that affect the radon distribution within a charcoal bed that can be studied using the mathematical model include carrier gas relative humidity and flow velocity, and input radon concentration. In addition, the relative performances of several different charcoals can be studied, provided sufficient information about their adsorption, desorption, and diffusion constants is known.

  9. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 96, NO. D6, PAGES 10,941-10,954, JUNE 20, 1991 SpaceborneObservation of Columnar Water Vapor'

    E-print Network

    Stephens, Graeme L.

    Observation of Columnar Water Vapor' SSMI Observations and Algorithm STEPHENA. TJEMKES,· GRAEME L. STEPHENS,AND DARREN L vapor is described. This methodusesboth the horizontallyand vertically SatelliteProgram.The water vapor derivedfrom the SSMI observationsis validatedagainst

  10. Liquid-phase and vapor-phase dehydration of organic/water solutions

    DOEpatents

    Huang, Yu (Palo Alto, CA); Ly, Jennifer (San Jose, CA); Aldajani, Tiem (San Jose, CA); Baker, Richard W. (Palo Alto, CA)

    2011-08-23

    Processes for dehydrating an organic/water solution by pervaporation or vapor separation using fluorinated membranes. The processes are particularly useful for treating mixtures containing light organic components, such as ethanol, isopropanol or acetic acid.

  11. The Oxidation Rate of SiC in High Pressure Water Vapor Environments

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Robinson, R. Craig

    1999-01-01

    CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accounting for volatility of silica in water vapor, the parabolic rate constants for Sic in water vapor pressures of 0.7, 1.8 and 3.1 atm were determined. The dependence of the parabolic rate constant on the water vapor pressure yielded a power law exponent of one. Silica growth on Sic is therefore limited by transport of molecular water vapor through the silica scale.

  12. The Feasibility of Forecasting Cirrus Cloud Cover and Water Vapor Above Telescope Sites in Northern Chile

    NASA Astrophysics Data System (ADS)

    Erasmus, D. A.; Peterson, R.

    1997-02-01

    This paper presents the results of a study conducted to examine the feasibility of forecasting cirrus cloud cover and atmospheric water vapor at European Southern Observatory (ESO) telescope sites in Chile at Paranal and La Silla. 6.7 ?m imagery from the Meteosat-3 satellite was used to quantify water vapor and cirrus cloud cover conditions above the sites. Using these data in conjunction with upper-air meteorological data, a method was developed to forecast the amount and type of cirrus cloud cover and water vapor above the telescopes. Forecasts were made of moisture and cloud parameters for four periods in 1993 and 1994 and evaluated by an objective comparison of forecasted and measured values. The results clearly indicate that it is feasible to forecast water vapor and cirrus cloud conditions above Paranal and La Silla with an accuracy that would be useful for telescope scheduling. (SECTION: Atmospheric Phenomena and Seeing)

  13. Physical Mechanisms Controlling Upper Tropospheric Water Vapor as Revealed by MLS Data from UARS

    NASA Technical Reports Server (NTRS)

    Newell, Reginald E.; Douglass, Anne (Technical Monitor)

    2002-01-01

    The third year and final report on the physical mechanisms controlling upper tropospheric water vapor revealed by the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) is presented.

  14. RECIPES FOR WRITING ALGORITHMS TO RETRIEVE COLUMNAR WATER VAPOR FOR 3-BAND MULTI-SPECTRAL DATA.

    SciTech Connect

    Borel, C. C. (Christoph C.); Hirsch, K. L. (Karen L.); Balick, L. K. (Lee K.)

    2001-01-01

    Many papers have considered the theory of retrieving columnar water vapor using the continuum interpolated band ratio (CIBR) and a few the atmospherically pre-corrected differential absorption (APDA) methods. In this paper we aim at giving recipes to actually implement CIBR and APDA for the Multi-spectral Thermal Imager (MTI) with the hope that they can be easily adapted to other sensors such as MODIS, AVIRIS and HYDICE. The algorithms have the four following steps in common: (1) running a radiative transfer (RT) algorithm for a range of water vapor values and a particular observation geometry, (2) computation of sensor band-averaged radiances, (3) computation of a non-linear fit of channel ratios (CIBR or APDA) as a function of water vapor, (4) application of the inverse fit to retrieve columnar water vapor as a function of channel ratio.

  15. Interaction of aerosol particles composed of protein and salts with water vapor: hygroscopic growth and microstructural rearrangement

    Microsoft Academic Search

    E. Mikhailov; S. Vlasenko; R. Niessner; U. Pöschl

    2004-01-01

    The interaction of aerosol particles composed of the protein bovine serum albumin (BSA) and the inorganic salts sodium chloride and ammonium nitrate with water vapor has been investigated by hygroscopicity tandem differential mobility analyzer (H-TDMA) experiments complemented by transmission electron microscopy (TEM) and Köhler theory calculations (100-300nm particle size range, 298K, 960hPa). BSA was chosen as a well-defined model substance

  16. Interaction of aerosol particles composed of protein and salts with water vapor: hygroscopic growth and microstructural rearrangement

    Microsoft Academic Search

    E. Mikhailov; S. Vlasenko; R. Niessner; U. Pöschl

    2003-01-01

    The interaction of aerosol particles in the 100-200 nm size range composed of the protein bovine serum albumin (BSA) and the inorganic salts sodium chloride and ammonium nitrate with water vapor at ambient temperature and pressure (25°C, 1 atm) has been investigated by hygroscopicity tandem differential mobility analyzer (H-TDMA) experiments complemented by transmission electron microscopy (TEM) and Köhler theory calculations.

  17. Vapor-liquid equilibrium of amine-water systems

    E-print Network

    Chun, Kil Whan

    1966-01-01

    methods of this type for predicting deviations from ideality is that of Hildebrand (43), which employs solubility parameters calculated from molar volumes and heats of vaporization. A similar approach has been developed by Gilmont, Zudkevitch...

  18. Fatigue Resistance of Asphalt Mixtures Affected by Water Vapor Movement

    E-print Network

    Tong, Yunwei

    2013-11-08

    the fatigue crack growth of pavement would result from such moisture accumulation. To fulfill these two objectives, a diffusion model was first established to illustrate the wetting process of the surface asphalt layer due to the vapor migration from subgrade...

  19. AIR HUMIDITY WITHIN BOUNDARYLAYER OF A TRANSPIRING LEAF 11. PROFILE OF WATER VAPOR DENSITY WITHIN THE BOUNDARYLAYER

    Microsoft Academic Search

    M. KITANO; H. EGUCHI

    KITANO M. and EGucm H. Air humidity within boundary layer ofa transpiring leaf If. Profile ofwater vapor density within the boundary layer. BIOTRONICS 16, 47-55, 1987. Profile of water vapor density near the cucumber leaf surface was examined in comparison with air temperature profile in relation to effects of air current and stomatal responses to environment. Profile of water vapor

  20. Influence of water vapor and oxygen on the tribology of carbon materials with sp 2 valence configuration

    Microsoft Academic Search

    B. K. Yen

    1996-01-01

    The tribological behaviors of graphite, non-graphitic carbon, carbon-carbon composite, and unhydrogenated amorphous carbon in nitrogen and air are investigated. The friction and wear of all carbon materials can be similarly influenced by water vapor and oxygen. Carbon materials generally exhibit a high friction and wear behavior when there is a lack of lubricant vapors in the environment. Water vapor, even

  1. Volatilized tritiated water vapor in the vicinity of exposed tritium contaminated groundwater

    SciTech Connect

    Dunn, D.L.; Carlton, B.; Hunter, C.; McAdams, T.

    1994-06-01

    Water vapor tritium concentrations in air above a known source of tritiated water can be estimated. Estimates should account for the mechanisms of evaporation and condensation at the water surface and water species exchange, and are typically applicable under a broad range of wind, temperature and humidity conditions. An estimate of volatilized tritium water vapor was made for a known outcropping of tritium contaminated groundwater at the Savannah River Site (SRS) old F-Area effluent stream. In order to validate this estimate and the associated dose calculation, sampling equipment was fabricated, tested, and installed at the effluent stream. The estimate and the dose calculation were confirmed using data from samples collected.

  2. Improved Daytime Column-Integrated Precipitable Water Vapor from Vaisala Radiosonde Humidity Sensors

    Microsoft Academic Search

    K. E. Cady-Pereira; M. W. Shephard; D. D. Turner; E. J. Mlawer; S A. Clough; T. J. Wagner

    2008-01-01

    ABSTRACT Accurate water vapor profiles from radiosondes are essential for long-term climate prediction, weather prediction, validation of remote sensing retrievals, and other applications. The Vaisala RS80, RS90, and RS92 radiosondes are among the more commonly deployed radiosondes in the world. However, numerous investigators have shown,that the daytime,water vapor profiles measured,by these instruments,present a significant dry bias due to the solar

  3. The Time Series of Terra and Aqua MODIS Near-IR Water Vapor Products

    Microsoft Academic Search

    Bo-Cai Gao; Rong-Rong Li

    2008-01-01

    Two Moderate Resolution Imaging SpectroRadiometer (MODIS) instruments [1] on the NASA Terra and Aqua Spacecraft platforms are currently operational for global remote sensing of the land, ocean and atmosphere. Both MODIS instruments are equipped with channels located within and around the 0.94-micron water vapor band absorption region for water vapor measurements over reflective land surfaces, clouds, and oceanic regions with

  4. Estimation of the Precipitable Water Vapor from ground-based GPS with GAMIT\\/GLOBK

    Microsoft Academic Search

    Xiaoming Li; Lisheng Xu; Yansong Fang; Yujie Zhang; Jilie Ding; Hailei Liu; Xiaobo Deng

    2010-01-01

    Information about the amount and spatial structure of atmospheric water vapor is essential in understanding weather forecasting and climate change. This paper mainly discuss the principles and methods to deduce the atmospheric Precipitable Water Vapor (PWV) from ground-based GPS observations by using a high accuracy GPS processing software package- GAMIT\\/GLOBK version 10.34. A GPS-network including 6 ground-based GPS receiving stations

  5. Is There Evidence of Convectively Injected Water Vapor in the Lowermost Stratosphere Over Boulder, Colorado?

    NASA Astrophysics Data System (ADS)

    Hurst, D. F.; Rosenlof, K. H.; Davis, S. M.; Hall, E. G.; Jordan, A. F.

    2014-12-01

    Anderson et al. (2012) reported the frequent presence of convectively injected water vapor in the lowermost stratosphere over North America during summertime, based on aircraft measurements. They asserted that enhanced catalytic ozone destruction within these wet stratospheric air parcels presents a concern for UV dosages in populated areas, especially if the frequency of deep convective events increases. Schwartz et al.(2013) analyzed 8 years of more widespread Aura Microwave Limb Sounder (MLS) measurements of lower stratospheric water vapor over North America and concluded that anomalously wet (>8 ppm) air parcels were present only 2.5% of the time during July and August. However, given the 3-km vertical resolution of MLS water vapor retrievals in the lowermost stratosphere, thin wet layers deposited by overshooting convection may be present but not readily detectable by MLS. Since 1980 the balloon-borne NOAA frost point hygrometer (FPH) has produced nearly 400 high quality water vapor profiles over Boulder, Colorado, at 5-m vertical resolution from the surface to the middle stratosphere. The 34-year record of high-resolution FPH profiles obtained over Boulder during summer months is evaluated for evidence of convectively injected water vapor in the lowermost stratosphere. A number of approaches are used to assess the contributions of deep convection to the Boulder stratospheric water vapor record. The results are compared to those based on MLS profiles over Boulder and the differences are discussed. Anderson, J. G., D. M. Wilmouth, J. B. Smith, and D. S. Sayres (2012), UV dosage levels in summer: Increased risk of ozone loss from convectively injected water vapor, Science, 337(6096), 835-839, doi:10.1126/science.1222978. Schwartz, M. J., W. G. Read, M. L. Santee, N. J. Livesey, L. Froidevaux, A. Lambert, and G. L. Manney (2013), Convectively injected water vapor in the North American summer lowermost stratosphere, Geophys. Res. Lett., 40, 2316-2321, doi:10.1002/grl.50421.

  6. Rapid formation of Jupiter by diffuse redistribution of water vapor in the solar nebula

    Microsoft Academic Search

    David J. Stevenson; Jonathan I. Lunine

    1988-01-01

    In the present, water-vapor diffusive redistribution and condensation model of solid material abundance enhancement in the solar nebula's Jupiter-formation region, the assumed turbulent nebula temperatures decrease inversely with radial distance from the center, and time-scales are set by turbulent viscosities. The length scale for condensation of diffusively-transported water vapor is about 0.4 AU, and the surface density of ice in

  7. Observations of precipitable water vapor fluctuations in convective boundary layer via microwave interferometry

    Microsoft Academic Search

    X. M. Shao; R. C. Carlos; M. W. Kirkland; C.-Y. J. Kao; A. R. Jacobson

    1999-01-01

    At microwave frequencies, each centimeter of precipitable water vapor (PWV) causes about 6.45 cm of extra electrical path length relative to the {open_quotes}dry{close_quotes} air. The fluctuations of the water vapor dominate the changes of the effective path length through the atmosphere in a relatively short time period of a few hours. In this paper we describe a microwave interferometer developed

  8. Effects of Nano to Micropore Diameter on Water Vapor Transport Diffusivities Within Porous Polycarbonate Barriers

    Microsoft Academic Search

    Matthew J. Traum; Edwin L. Thomas; William A. Peters

    2011-01-01

    Effective pore diffusivities for dilute water vapor in air were measured at atmospheric pressure and 30°C by continuously weighing an evaporator capped with a porous polycarbonate barrier and correcting steady-state water vapor fluxes for apparatus mass transfer resistances. The Knudsen number was increased from 0.018 to 2.4 at constant pressure by decreasing pore diameter from 5,400 to 39 nm, thus

  9. DIURNAL CYCLE OF PRECIPITABLE WATER VAPOR OVER SPAIN

    SciTech Connect

    Ortiz de Galisteo, J. P.; Cachorro, V. E.; Toledano, C.; Torres, B.; Laulainen, Nels S.; Bennouna, Yasmine; de Frutos, A. M.

    2011-05-20

    Despite the importance of the diurnal cycle of precipitable water vapor (PWV), its knowledge is very limited due to the lack of data with sufficient temporal resolution. Currently, from GPS receivers, PWV can be obtained with high temporal resolution in all weather conditions for all hours of the day. In this study we have calculated the diurnal cycle of PWV for ten GPS stations over Spain. The minimum value is reached approximately at the same time at all the stations, ~0400-0500 UTC, whereas the maximum is reached in the second half of the day, but with a larger dispersion of its occurrence between stations. The amplitude of the cycle ranges between 0.72 mm and 1.78 mm. The highest values are recorded at the stations on the Mediterranean coast, with a doubling of the values of the stations on the Atlantic coast or inland. The amplitude of the PWV cycle, relative to the annual mean value, ranges between 8.8 % on the Mediterranean coast and 3.6 % on the Atlantic coast. Two distinctly different seasonal diurnal cycles have been identified, one in winter and other in summer, with spring and autumn being only transition states. The winter cycle is quite similar at all locations, whereas in summer, local effects are felt strongly, making the diurnal cycle quite different between stations. The amplitude of the summer cycle is 1.69 mm, it is almost double the winter one (0.93 mm). Analogous to the annual cycles, the seasonal cycles of the different stations are more similar during the night and early morning hours than during the afternoon. The observed features of the PWV diurnal cycle are explained in a qualitative way on the basis of the air temperature, the transport of moisture by local winds, and the turbulent vertical mixing.

  10. A parameterized yet accurate model of ozone and water vapor transmittance in the solar-to-near-infrared spectrum

    NASA Astrophysics Data System (ADS)

    Liu, Weiyi; Qiu, Jinhuan

    2012-05-01

    A parameterized transmittance model (PTR) for ozone and water vapor monochromatic transmittance calculation in the solar-to-near-infrared spectrum 0.3-4 µm with a spectral resolution of 5 cm-1 was developed based on the transmittance data calculated by Moderate-resolution Transmittance model (MODTRAN). Polynomial equations were derived to represent the transmittance as functions of path length and airmass for every wavelength based on the least-squares method. Comparisons between the transmittances calculated using PTR and MODTRAN were made, using the results of MODTRAN as a reference. Relative root-mean-square error (RMSre) was 0.823% for ozone transmittance. RMSre values were 8.84% and 3.48% for water vapor transmittance ranges of 1-1×10-18 and 1-1×10-3, respectively. In addition, the Stratospheric Aerosol and Gas Experiment II (SAGEII) ozone profiles and University of Wyoming (UWYO) water vapor profiles were applied to validate the applicability of PTR model. RMSre was 0.437% for ozone transmittance. RMSre values were 8.89% and 2.43% for water vapor transmittance ranges of 1-1×10-18 and 1-1×10-6, respectively. Furthermore, the optical depth profiles calculated using the PTR model were compared to the results of MODTRAN. Absolute RMS errors (RMSab) for ozone optical depths were within 0.0055 and 0.0523 for water vapor at all of the tested altitudes. Finally, the comparison between the solar heating rate calculated from the transmittance of PTR and Line-by-Line radiative transfer model (LBLRTM) was performed, showing a maximum deviation of 0.238 K d-1 (6% of the corresponding solar heating rate calculated using LBLRTM). In the troposphere all of the deviations were within 0.08 K d-1. The computational speed of PTR model is nearly two orders of magnitude faster than that of MODTRAN.

  11. Two decades of water vapor measurements with the FISH fluorescence hygrometer: A review

    NASA Astrophysics Data System (ADS)

    Rolf, Christian; Meyer, Jessica; Schiller, Cornelius; Rohs, Susanne; Spelten, Nicole; Afchine, Armin; Zöger, Martin; Sitnikov, Nikolay; Thornberry, Troy D.; Rollins, Andrew W.; Bozóki, Zoltan; Tátrai, David; Ebert, Volker; Kühnreich, Benjamin; Mackrodt, Peter; Möhler, Ottmar; Saathoff, Harald; Rosenlof, Karen H.; Krämer, Martina

    2015-04-01

    The Fast In-situ Stratospheric Hygrometer (FISH) is an airborne Lyman-? photofragment fluorescence hygrometer for accurate and precise measurement of total water mixing ratios (WMR) (gas phase + evaporated ice) in the upper troposphere and lower stratosphere (UT/LS) since almost two decades. Here, we present a comprehensive review of the measurement technique, calibration procedure, accuracy and reliability of FISH. A crucial part for the FISH measurement quality is the regular calibration to a water vapor reference, namely the commercial frostpoint hygrometer DP30. In the frame of this work this frostpoint hygrometer is compared to German and British traceable metrological water standards and its accuracy is found to be 2-4 %. Overall, in the range from 4-1000 ppmv, the total accuracy of FISH was found to be 6-8 % as stated also in previous publications. For lower mixing ratios down to 1 ppmv, the uncertainty reaches a lower limit of 0.3 ppmv. For specific, non-atmospheric conditions, as set in experiments at the AIDA chamber -namely mixing ratios below 10 ppmv and above 100 ppmv in combination with high and low pressure conditions- the need to apply a modified FISH calibration evaluation has been identified. The new evaluation improves the agreement of FISH with other hygrometers to ± 10% accuracy in the respective mixing ratio ranges. Further, a quality check procedure for high total water measurements in cirrus clouds at high pressures (400-500 hPa) is introduced. The performance of FISH in the field is assessed by reviewing intercomparisons of FISH water vapor data with other in-situ and remote sensing hygrometers over the last two decades. We find that the agreement of FISH with the other hygrometers has improved over that time span from overall up to ±30% or more to about ±5-20% @10ppmv. We will show here that the robust and continuous calibration and operation procedures of the FISH instrument over the last two decades establish FISH as one of the core instruments for in-situ observations of water vapor in the UT/LS.

  12. Solvation of hydrogen sulfide in liquid water and at the water-vapor interface using a polarizable force field.

    PubMed

    Riahi, Saleh; Rowley, Christopher N

    2014-02-01

    Molecular dynamics (MD) simulations using the Drude polarizable force field are used to study the solution and interfacial properties of hydrogen sulfide (H2S) in water. Pairwise H2O-H2S Lennard-Jones interactions were optimized to the experimental H2S gas solubility at 298 K. These parameters yield hydration free energies and diffusion coefficients for H2S that are in good agreement with the experiment over 273-323 K and 298-368 K, respectively. H2S is sparingly soluble in water, with a ?G(hydr)° of -0.5 kcal mol(-1). The free energy perturbation (FEP) calculations and analysis of the radial distribution functions show that H2S has limited hydrogen bonding and electrostatic interactions with the water solvent and generally behaves like a hydrophobic solute. These features were confirmed by ab initio MD simulations. Umbrella sampling simulations were used to calculate the free energy profile of the transition of H2S across the water-vapor interface, which showed that H2S has a sizable surface excess, with a ?G(surf) of 1.3 kcal mol(-1). This high surface excess is consistent with our calculations of the surface tension, which decreases to 20 dyn cm(-1) under high densities of H2S (g). The dipole moment of H2S increases from its gas phase value of 0.98 to 1.25 D in bulk water as it moves across the interface. Adsorbed H2S tends to be oriented perpendicular to the interface, with the sulfur atom pointing toward the vapor phase. PMID:24498909

  13. Effect of Water Vapor Absorption on Measurements of Atmospheric Nitrate Radical by LP-DOAS

    NASA Astrophysics Data System (ADS)

    Li, Su-wen; Liu, Wen-qing; Xie, Pin-hua; Yang, Yi-jun; Chen, De-bao; Li, Zheng

    2008-10-01

    During the measurement of atmospheric nitrate radical by long-path differential optical absorption spec-troscopy, water vapor strong absorption could affect the measurement of nitrate radical and detection limits of system. Under the tropospheric condition, the optical density of water vapor absorption is non-linearly dependent on column density. An effective method was developed to eliminate the effect of water vapor absorption. Reference spectra of water vapor based on the daytime atmospheric absorption spectra, when fitted together with change of cross section with water vapor column densities, gave a more accurate fitting of water vapor absorptions, thus its effect on the measurements of nitrate radical could be restricted to a minimum and detection limits of system reached 3.6 ppt. The modified method was applied during an intensive field campaign in the Pearl River Delta, China. The NO3 concentration in polluted air masses varied from 3.6 ppt to 82.5 ppt with an average level of 23.6±1.8 ppt.

  14. Isotope ratios of precipitation and water vapor observed in Typhoon Shanshan

    NASA Astrophysics Data System (ADS)

    Fudeyasu, H.; Ichiyanagi, K.; Sugimoto, A.; Yoshimura, K.; Ueta, A.; Yamanaka, M. D.; Ozawa, K.

    2008-06-01

    Isotope ratios of precipitation and water vapor were observed during the passage of Typhoon Shanshan at Ishigaki Island, southwestern Japan, on 15-16 September 2006. Such high-resolution isotopic observations allow for qualitative understanding of atmospheric moisture cycling; they revealed that isotope ratios of both the precipitation and water vapor decreased radially inward in the cyclone's outer region; anomalously high isotope ratios appeared in the cyclone's inner region; and d-excess tended to decrease in the cyclone's inner region. In the cyclone's outer region, the water vapor was isotopically depleted due to the rainout effect which involves both condensation efficiency as reflected in inwardly increasing cloud thickness and isotopic exchange between falling droplets and the ambient water vapor. In contrast, water vapor in the cyclone's inner region was isotopically enriched due to weak rainout effect in conjunction with intensive isotopic recharge from the sea spray and sea surface with heavy isotope ratios. Since water vapor mainly acts as a source of precipitation, the isotope ratios of precipitation also had systematic variation. A unique circumstance is the intensity of isotopic exchange with almost saturated surface air and high winds, causing anomalously high isotope ratios and low d-excess values in the cyclone's inner region.

  15. Production of energy by direct contact of water immiscible working fluid with hot or warm water to vaporize liquid working fluid, utilization of vapor to produce mechanical energy and direct contact of spent vapor with cold or cool water to condense same. [Patent: direct contact heat exchangers

    Microsoft Academic Search

    C. S. Jr

    1977-01-01

    A low boiling water immiscible fluid containing two or more molecular species and having a variable boiling point is contacted in the liquid state with relatively hot or warm water such as surface sea water or geothermal water, thereby generating vapor of immiscible fluid (together with a certain amount of water vapor) which is used to drive a prime mover

  16. Effect of Water Vapor on Benzene Decomposition Using a Nonthermal-Discharge Plasma Reactor

    Microsoft Academic Search

    Atsushi Ogata; Noboru Shintani; Kazushi Yamanouchi; Koichi Mizuno; Satoshi Kushiyama; Toshiaki Yamamoto

    2000-01-01

    The effect of water vapor on benzene decomposition in air was investigatedusing a nonthermal-discharge plasma reactor packed with ferroelectricmaterials. The conversion of benzene was found to decrease with an increaseof water concentration. On the other hand, the selectivity to CO2 in thedecomposition products increased with an increase of water concentration. Acomparison between the benzene conversion to CO and CO2 suggested

  17. Can atmospheric pressure and water table fluctuations be neglected in soil vapor extraction?

    Microsoft Academic Search

    Kehua You; Hongbin Zhan

    Solutions to soil vapor extraction (SVE) are indispensable to characterize the unsaturated zone and to optimize SVE. Most of the existing solutions neglect the fluctuations of atmospheric pressure and water table. This study presents a new semi-analytical solution for SVE by considering the atmospheric pressure and water table fluctuations. Comparisons between the new and previous solutions indicate that the water

  18. Correction technique for Raman water vapor lidar signal-dependent bias and suitability for water vapor trend monitoring in the upper troposphere

    NASA Astrophysics Data System (ADS)

    Whiteman, D. N.; Cadirola, M.; Venable, D.; Calhoun, M.; Miloshevich, L.; Vermeesch, K.; Twigg, L.; Dirisu, A.; Hurst, D.; Hall, E.; Jordan, A.; Vömel, H.

    2012-11-01

    The MOHAVE-2009 campaign brought together diverse instrumentation for measuring atmospheric water vapor. We report on the participation of the ALVICE (Atmospheric Laboratory for Validation, Interagency Collaboration and Education) mobile laboratory in the MOHAVE-2009 campaign. In appendices we also report on the performance of the corrected Vaisala RS92 radiosonde measurements during the campaign, on a new radiosonde based calibration algorithm that reduces the influence of atmospheric variability on the derived calibration constant, and on other results of the ALVICE deployment. The MOHAVE-2009 campaign permitted the Raman lidar systems participating to discover and address measurement biases in the upper troposphere and lower stratosphere. The ALVICE lidar system was found to possess a wet bias which was attributed to fluorescence of insect material that was deposited on the telescope early in the mission. Other sources of wet biases are discussed and data from other Raman lidar systems are investigated, revealing that wet biases in upper tropospheric (UT) and lower stratospheric (LS) water vapor measurements appear to be quite common in Raman lidar systems. Lower stratospheric climatology of water vapor is investigated both as a means to check for the existence of these wet biases in Raman lidar data and as a source of correction for the bias. A correction technique is derived and applied to the ALVICE lidar water vapor profiles. Good agreement is found between corrected ALVICE lidar measurments and those of RS92, frost point hygrometer and total column water. The correction is offered as a general method to both quality control Raman water vapor lidar data and to correct those data that have signal-dependent bias. The influence of the correction is shown to be small at regions in the upper troposphere where recent work indicates detection of trends in atmospheric water vapor may be most robust. The correction shown here holds promise for permitting useful upper tropospheric water vapor profiles to be consistently measured by Raman lidar within NDACC (Network for the Detection of Atmospheric Composition Change) and elsewhere, despite the prevalence of instrumental and atmospheric effects that can contaminate the very low signal to noise measurements in the UT.

  19. Isotopic Variability in Surface Water Vapor and Precipitation in the Upper Midwest, USA

    NASA Astrophysics Data System (ADS)

    Schultz, N. M.; Griffis, T. J.; Baker, J. M.; Lee, X.; Erickson, M.; Zhang, X.; Xiao, W.; Hu, N.

    2010-12-01

    The isotopic composition of surface water vapor and precipitation provides important information about the moisture source characteristics and subsequent transport processes and phase changes in the atmosphere. The objective of this research is to investigate the characteristics of ?18O, ?D, and deuterium excess (d) in surface water vapor and precipitation in Rosemount, MN, a continental site characterized by hot, humid summers and cold, dry winters, and to explore the meteorological mechanisms that influence ?18O, ?D, and d. This research will add to the growing body of literature on the temporal dynamics of isotopes in water vapor and precipitation and may be used to identify and diagnose the impacts of global change on the hydrologic cycle. Water vapor isotope ratios and fluxes were measured continuously during the 2009 growing season (June 17 - Sept. 3) using a tunable diode laser (TDL) analyzer in eddy covariance mode. Precipitation samples were collected from 2006 - present and analyzed for their isotopic composition using an off-axis laser spectroscopy system. ?18O and ?D in precipitation showed large seasonal variability with a maximum of +0.85‰ and +3.6‰ in June, 2007 and a minimum of -29.8‰ and -225‰ in November, 2006. This observed seasonality in the isotope ratios agrees well with other continental mid-latitude sites and is indicative of Rayleigh rain-out processes and the changing air mass origin. Deuterium excess was high (>10‰) in warm season heavy rain events, suggesting the contribution of locally evaporated water to the precipitable water in the atmosphere. The isotope ratios of water vapor were highly variable, ranging from -33‰ to -5‰ for ?18O and -275‰ and -25‰ for ?D. This variability is related to the prevailing meteorologic conditions and advection of moisture from different source regions. ?18O and ?D showed a positive correlation with the water vapor mixing ratio, and d showed a negative correlation with relative humidity (RH). During periods of high ?18O and ?D, back-trajectory analysis showed advection from the south, suggesting the primary source of water vapor to be the Gulf of Mexico. Periods of low ?18O and ?D correspond to advection from the northwest, suggesting the Pacific Ocean as the primary source of moisture. Variations in ?18O and ?D in the boundary layer reflect the combined effect of surface evapotranspiration and entrainment from the upper atmosphere. New tall tower isotopic vapor measurements currently measured at two heights (3m and 200m) will provide new insight into the still uncertain effect of atmospheric entrainment on surface water vapor isotopes, and a regional-scale analysis of the isotopic water vapor budget.

  20. Liquid-Vapor Equilibrium Isotopic Fractionation of Water. How well can classical water models predict it?

    SciTech Connect

    Chialvo, Ariel A [ORNL; Horita, Juske [ORNL

    2009-01-01

    The liquid-vapor equilibrium isotopic fractionation of water is determined by molecular-based simulation, via Gibbs Ensemble Monte Carlo and isothermal-isochoric molecular dynamics involving two radically different but realistic models, the extended simple point charge (SPC/E) and the Gaussian charge polarizable (GCP) models. The predicted temperature dependence of the liquid-vapor equilibrium isotopic fractionation factors for H 2 18O / H 2 16O, H 2 17O / H 2 16O, and 2H 1H 16O / 1H 2 16O are compared against the most accurate experimental datasets to assess the ability of these intermolecular potential models to describe quantum effects according to the Kirkwood-Wigner free energy perturbation ! 2 !expansion. Predictions of the vapor pressure isotopic effect for the H 2 18O / H 2 16O and H 2 17O / H 2 16O pairs are also presented in comparison with experimental data and two recently proposed thermodynamic modeling approaches. Finally, the simulation results are used to discuss some approximations behind the microscopic interpretation of isotopic fractionation based on the underlying roto-translational coupling.

  1. The Use of Sage Water Vapor Data for Investigating Climate Change Issues

    NASA Technical Reports Server (NTRS)

    Rind, D.

    2003-01-01

    SAGE water vapor data has proven valuable for addressing several of the important issues in climate change research. It has been used to investigate how the upper troposphere water vapor responds to warming and convection, a key question in understanding the water vapor feedback to anthropogenic global warming. In the case of summer versus winter differences, SAGE results showed that the upper tropospheric relative humidity remained approximately constant; this result was in general agreement with how a GCM handled the seasonal difference, and gave credence to the argument that the GCM was not overestimating the water vapor feedback associated with convection. In addition, the convection-water vapor relationship was investigated further using SAGE water vapor and ISCCP cloud data. The results showed that upper tropospheric drying did appear to occur simultaneously with deep convective events in the tropics, only to be replaced by moistening a few hours later, associated (most likely) with the reevaporation of moisture from anvil clouds. The total effect was, again, a moistening of the upper troposphere associated with convection. Calculation of the actual trends in upper tropospheric moisture is a potential goal for SAGE data usage; trends calculated with radiosonde data, or instruments calibrated with radiosonde data have the problem of the effect of changing radiosonde instruments. SAGE data have in effect been used to compare different radiosondes through comparisons, and could continue to do so. SAGE 3 should also help clarify the absolute accuracy of SAGE retrievals in the troposphere. and its consequences. Model results show that water vapor increases can help explain the observations of stratospheric cooling, along with increasing C02 and ozone reduction. SAGE has been shown to provide trends similar to those of some other satellite and in situ retrievals, with increasing water vapor over time. However, SAGE is impacted by aerosol contamination which must be removed from the data; approaches used in the past will be reviewed. The SAGE water vapor errors, if taken literally, would make it hard to justify using SAGE data for such trends, and the error bars must be investigated. Stratospheric water vapor increases, like tropospheric increases, would lead to noticeable warming at the surface, and their changes must be quantified.

  2. PROGRESS REPORT OF FY 2004 ACTIVITIES: IMPROVED WATER VAPOR AND CLOUD RETRIEVALS AT THE NSA/AAO

    SciTech Connect

    E. R. Westwater; V. V. Leuskiy; M. Klein; A. J. Gasiewski; and J. A. Shaw

    2004-11-01

    The basic goals of the research are to develop and test algorithms and deploy instruments that improve measurements of water vapor, cloud liquid, and cloud coverage, with a focus on the Arctic conditions of cold temperatures and low concentrations of water vapor. 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 Program. Although several technologies have been investigated to measure these column amounts, microwave radiometers (MWR) have been used operationally by the ARM program for passive retrievals of these quantities: precipitable water vapor (PWV) and integrated water liquid (IWL). The technology of PWV and IWL retrievals has advanced steadily since the basic 2-channel MWR was first deployed at ARM CART sites Important advances are the development and refinement of the tipcal calibration method [1,2], and improvement of forward model radiative transfer algorithms [3,4]. However, the concern still remains that current instruments deployed by ARM may be inadequate to measure low amounts of PWV and IWL. In the case of water vapor, this is especially important because of the possibility of scaling and/or quality control of radiosondes by the water amount. Extremely dry conditions, with PWV less than 3 mm, commonly occur in Polar Regions during the winter months. Accurate measurements of the PWV during such dry conditions are needed to improve our understanding of the regional radiation energy budgets. The results of a 1999 experiment conducted at the ARM North Slope of Alaska/Adjacent Arctic Ocean (NSA/AAO) site during March of 1999 [5] have shown that the strength associated with the 183 GHz water vapor absorption line makes radiometry in this frequency regime suitable for measuring low amounts of PWV. As a portion of our research, we conducted another millimeter wave radiometric experiment at the NSA/AAO in March-April 2004. This experiment relied heavily on our experiences of the 1999 experiment. Particular attention was paid to issues of radiometric calibration and radiosonde intercomparisons. Our theoretical and experimental work also supplements efforts by industry (F. Solheim, Private Communication) to develop sub-millimeter radiometers for ARM deployment. In addition to quantitative improvement of water vapor measurements at cold temperature, the impact of adding millimeter-wave window channels to improve the sensitivity to arctic clouds was studied. We also deployed an Infrared Cloud Imager (ICI) during this experiment, both for measuring continuous day-night statistics of the study of cloud coverage and identifying conditions suitable for tipcal analysis. This system provided the first capability of determining spatial cloud statistics continuously in both day and night at the NSA site and has been used to demonstrate that biases exist in inferring cloud statistics from either zenith-pointing active sensors (lidars or radars) or sky imagers that rely on scattered sunlight in daytime and star maps at night [6].

  3. A Regional-Scale Assessment of Satellite Derived Precipitable Water Vapor Across The Amazon Basin

    NASA Technical Reports Server (NTRS)

    DeLiberty, Tracy; Callahan, John; Guillory, Anthony R.; Jedlovec, Gary

    2000-01-01

    Atmospheric water vapor is widely recognized as a key climate variable, linking an assortment of poorly understood and complex processes. It is a major element of the hydrological cycle and provides a mechanism for energy exchange among many of the Earth system components. Reducing uncertainty in our current knowledge of water vapor and its role in the climate system requires accurate measurement, improved modeling techniques, and long-term prediction. Satellites have the potential to satisfy these criteria, as well as provide high resolution measurements that are not available from conventional sources. The focus of this paper is to examine the temporal and mesoscale variations of satellite derived precipitable water vapor (PW) across the Amazon Basin. This region is pivotal in the functioning of the global climate system through its abundant release of latent heat associated with heavy precipitation events. In addition, anthropogenic deforestation and biomass burning activities in recent decades are altering the conditions of the atmosphere, especially in the planetary boundary layer. A physical split-window (PSW) algorithm estimates PW using images from the GOES satellites along with the NCEP/NCAR Reanalysis data that provides the first guess information. Retrievals are made at a three-hourly time step during daylight hours in the Amazon Basin and surrounding areas for the months of June and October in 1988 (dry year) and 1995 (wet year). Spatially continuous fields are generated 5 times daily at 12Z, 15Z, 18Z, 21Z, and 00Z. These fields are then averaged to create monthly and 3 hourly monthly grids. Overall, the PSW estimates PW reasonable well in the Amazon with MAE ranging from 3.0 - 9.0 mm and MAE/observed mean around 20% in comparison to radiosonde observations. The distribution of PW generally mimics that of precipitation. Maximum values (42 - 52 mm) are located in the Northwest whereas minimum values (18 - 27 mm) are found along Brazil's East coast. Aside from the East coast, PW has a stronger north-south gradient than that of rainfall. As for the temporal variation of PW, June (1988 and 1995) experiences a peak about 1400 local time, corresponding to a maximum in air temperature. In contrast, October (1988 and 1995) experiences a maximum early in the day, 1100 local time, with a gradual decrease toward nighttime.

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

    NASA Technical Reports Server (NTRS)

    Ismail, Syed; Browell, Edward V.

    1989-01-01

    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 Center for operation on a high altitude ER-2 aircraft. The analysis shows that a less than 10-percent H2O profile measurement accuracy is possible for the LASE system with a vertical and horizontal resolution of 200 m and 10 km, respectively, at night and 300 m and 20 km during the day. Global measurements of H2O profiles from spaceborne DIAL systems can be made to a similar accuracy with a vertical resolution of 500 m and a horizontal resolution of 100 km.

  5. A water-vapor radiometer error model. [for ionosphere in geodetic microwave techniques

    NASA Technical Reports Server (NTRS)

    Beckman, B.

    1985-01-01

    The water-vapor radiometer (WVR) is used to calibrate unpredictable delays in the wet component of the troposphere in geodetic microwave techniques such as very-long-baseline interferometry (VLBI) and Global Positioning System (GPS) tracking. Based on experience with Jet Propulsion Laboratory (JPL) instruments, the current level of accuracy in wet-troposphere calibration limits the accuracy of local vertical measurements to 5-10 cm. The goal for the near future is 1-3 cm. Although the WVR is currently the best calibration method, many instruments are prone to systematic error. In this paper, a treatment of WVR data is proposed and evaluated. This treatment reduces the effect of WVR systematic errors by estimating parameters that specify an assumed functional form for the error. The assumed form of the treatment is evaluated by comparing the results of two similar WVR's operating near each other. Finally, the observability of the error parameters is estimated by covariance analysis.

  6. Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere.

    PubMed

    Gorski, Galen; Strong, Courtenay; Good, Stephen P; Bares, Ryan; Ehleringer, James R; Bowen, Gabriel J

    2015-03-17

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios. We show that during periods of relatively low humidity and/or atmospheric stagnation, this isotopic signature can be used to quantify the concentration of water of combustion in the atmospheric boundary layer over Salt Lake City. Combustion-derived vapor concentrations vary between periods of atmospheric stratification and mixing, both on multiday and diurnal timescales, and respond over periods of hours to variations in surface emissions. Our estimates suggest that up to 13% of the boundary layer vapor during the period of study was derived from combustion sources, and both the temporal pattern and magnitude of this contribution were closely reproduced by an independent atmospheric model forced with a fossil fuel emissions data product. Our findings suggest potential for water vapor isotope ratio measurements to be used in conjunction with other tracers to refine the apportionment of urban emissions, and imply that water vapor emissions associated with combustion may be a significant component of the water budget of the urban boundary layer, with potential implications for urban climate, ecohydrology, and photochemistry. PMID:25733906

  7. Mars' water vapor mapping by the SPICAM IR spectrometer: Five martian years of observations

    NASA Astrophysics Data System (ADS)

    Trokhimovskiy, Alexander; Fedorova, Anna; Korablev, Oleg; Montmessin, Franck; Bertaux, Jean-Loup; Rodin, Alexander; Smith, Michael D.

    2015-05-01

    The SPICAM IR instrument on the Mars Express mission continuously observes the water vapor in the martian atmosphere starting from 2004 in the 1.38-?m spectral band. The water vapor column abundance is retrieved from nadir observations to characterize its spatial, seasonal and interannual variations. A reference set of SPICAM water vapor column abundances (zonally averaged) covering the time period from 2004 to 2013 (martian years 27-31) is available for a grid of 2° Ls × 2° latitude, along with an average reference map of water vapor abundance combining all the martian years of Mars Express observations. Compared to the previous data retrieval by Fedorova et al. (Fedorova, A., Korablev, O., Bertaux, J.L., Rodin, A., Kiselev, A., Perrier, S. [2006]. J. Geophys. Res. 111, E09S08) the new processing algorithm includes many improvements concerning the calibration and assumed parameters. A major improvement is the account for aerosol scattering based on dust and water ice cloud optical depths measured by THEMIS/Mars Odyssey (Smith, M.D. [2009]. Icarus 202, 444-452). The account for multiple scattering by aerosol particles increases the retrieved water vapor amount by ?10% in polar areas during summer, and up to 60-70% for large solar zenith angles. The sensitivity of the results to aerosol properties, surface albedo, solar spectrum, and water vapor vertical distribution has also been studied. The retrieved water vapor reveals nominal annual cycle with maximum abundance of about 60-70 pr. ?m for the Northern summer and ?20 pr. ?m for the Southern summer. The annual average amount of water has been estimated to be of 10-20 pr. ?m, in agreement with other measurements. From year to year the seasonal cycle of water vapor abundance is very stable. An observed decrease during the MY 28 global dust storm cannot be fully attributed to the masking effect of dust, and indicates a real decrease of water amount near or above the surface. No evidence of diurnal variation of column water vapor amount was found, even though the 1.38-?m measurements are sensitive to the few lowermost kilometers above the surface.

  8. Comparison of Raman lidar water vapor calibration using GPS, radiosoundigs and ground observations. Application for GPS positioning purpose

    NASA Astrophysics Data System (ADS)

    Bosser, P.; Bock, O.; Thom, C.; Pelon, J.

    2011-12-01

    Water vapor measurements from a mobile Raman lidar developed conjointly by IGN and LATMOS/CNRS are used for documenting water vapor heterogeneities in the lower troposphere and correcting geodetic (as GPS) radio-signal propagation delays in clear sky conditions. This instrument has both capabilities for realizing zenith pointing and slant pointing measurements. This instrument has been involved in different experiments in these past few years (VAPIC-2004, COPS-2007, MANITOUL-2009) providing an interesting set of data acquired under various atmospheric conditions in different geographic areas. These data are now used to evaluate different strategies for lidar humidity measurement calibration, considering collocated GPS observations, radiosoundings profiles and humidity measurements. A new method of calibration using GPS observations analysis has therefore been developed. The joint processing of GPS and lidar data is also shown to improve the GPS positioning.

  9. Description and overview of an instrument designed to measure line-of-sight delay due to water vapor

    NASA Technical Reports Server (NTRS)

    Resch, G. M.; Chavez, M. C.; Yamane, N. I.

    1983-01-01

    Eight dual channel microwave radiometers were constructed as a research and development effort for the Crustal Dynamics Project and the Deep Space Network. These instruments, known as water vapor radiometers, are primarily intended to demonstrate that the variable path delay imposed by atmospheric water vapor can be calibrated in microwave tracking and distance measuring systems but could also be used in other applications involving moist air meteorology and propagation studies. They are being deployed to various stations and observatories that participate in Very Long Baseline Interferometry experiments. The development history of these instruments are reviewed, the theory of operation and overall design considerations are outlined, and the instrumental parameters and performance characteristics are described.

  10. Photothermal configuration applied to the study of water vapor permeability in biodegradable films under several water activities

    NASA Astrophysics Data System (ADS)

    Lopez-Bueno, G.; Martín-Martínez, E. San; Cruz-Orea, A.; Tomas, S. A.; Tufiño, M.; Sanchez, F.

    2003-01-01

    A photothermal configuration was used to determine the water vapor permeability of biodegradable films (nixtamalized corn pericarps). The films were obtained from corn grains boiled in an alkaline solution containing water and Ca(OH)2. Samples were exposed to saturated salt solutions with relative humidity in the range 7%-97%. The water vapor diffusion coefficient was determined as a function of relative humidity. The obtained coefficients agreed with data available in the literature. It was also found that the photoacoustic amplitude shows a linear dependence on the water activity, in agreement with our theoretical model.

  11. Vibrational Sum-Frequency Studies of a Series of Phospholipid Monolayers and the Associated Water Structure at the Vapor/Water Interface

    E-print Network

    Richmond, Geraldine L.

    Structure at the Vapor/Water Interface Mark R. Watry, Teresa L. Tarbuck, and Geraldine L. Richmond at the vapor/water interface have been investigated using vibrational sum-frequency spectroscopy under different polarization schemes for monolayers at the vapor/D2O interface to examine chain ordering

  12. High-frequency measurements of atmospheric stable water vapor isotopes in the tropics (Sulawesi, Indonesia)

    NASA Astrophysics Data System (ADS)

    Brown, M.; Knohl, A.; Kreilein, H.; Zanotelli, D.; Rauf, A.; Barus, H.

    2012-04-01

    Recent advances in cavity ring-down spectroscopy have enabled the continuous long-term measurement of atmospheric stable water vapor isotopes, which represent a powerful tool to investigate transport processes and sources of atmospheric water vapor. Here, we present continuous measurements of ?2H and ?18O of atmospheric water vapor made with a Picarro water vapor isotope analyzer (L2120-I, Picarro Inc.) from the roof top of our laboratory in Palu, Sulawesi, Indonesia. These are among the first known continuous high-frequency measurements made in the tropics, where water vapor plays a central role in the energy and water balance and where climate change is expected to significantly alter patterns of evapotranspiration and precipitation. We first characterize the accuracy and performance of the analyzer in terms of precision, memory effects and concentration dependency and assess its suitability for continuous remote long-term measurements. We then attempt to determine the source of atmospheric water vapor in Palu using measurements of ?2H and ?18O from precipitation and surface air, and explore the influence of wind speed, wind direction, atmospheric humidity and air temperature on variations in isotope ratios. The isotope analyzer was calibrated periodically using a standards delivery module in combination with a vaporizer included with the analyzer. From March to August 2011 the analyzer drift was <5.0 ‰ for ?2H and <1.2 ‰ for ?18O. Precision (one standard deviation) at a 60 s averaging time was 0.06 ‰ for ?2H and 0.03 ‰ for ?18O. From mid-April to late-June, 1-hour averages of surface air ?2H and ?18O ranged from -70 to -210 ‰ and from -15 to -35 ‰, respectively.

  13. Reduction of Legionella spp. in water and in soil by a citrus plant extract vapor.

    PubMed

    Laird, Katie; Kurzbach, Elena; Score, Jodie; Tejpal, Jyoti; Chi Tangyie, George; Phillips, Carol

    2014-10-01

    Legionnaires' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml(-1) on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and ?-pinene) was conducted. There was up to a 5-log cells ml(-1) reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml(-1) reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. PMID:25063652

  14. Retrieval of the global water vapor distribution from satellite observations in the blue spectral range

    NASA Astrophysics Data System (ADS)

    Wagner, Thomas; Beirle, Steffen; Mies, Kornelia

    2012-07-01

    Water vapor is involved in many important chemical reactions in the atmosphere and contributes most to the natural greenhouse effect. Its atmospheric abundance is highly variable. Thus observations of the spatio-temporal variation on a global scale are of great importance. Water vapor observations are possible in different spectral ranges, e.g. in the microwave, thermal IR or near IR and visible spectral range. Satellite measurements in the red spectral range have the advantage that they are sensitive for the whole atmospheric column and that they provide global coverage. In this study we exploit the potential to retrieve the global water vapor distribution from satellite observations in the blue spectral range. Although the water vapor absorption in this spectral region is rather weak, such retrievals also have their advantages: First, because of the weak absorption, no corrections for spectral saturation effects (like in the red spetral region) have to be applied. Second, the surface albedo in the blue spectral region is very similar for land and ocean. Third, the water vapor distribution can be retrieved also from satellite instruments, which do not cover the red spectral range (like e.g. OMI or the future Sentinel missions). Here we show first retrievals of the water vapor column in the blue spectral range from the GOME-2 instrument on METOP. Since GOME-2 also covers the red spectral region, a direct comparison with the results of the standard water vapor retrieval is possible. We characterise the accuracy and the detection limit of the new H2O analysis.

  15. Development of a 266 nm Raman lidar for profiling atmospheric water vapor

    NASA Astrophysics Data System (ADS)

    Uesugi, T.; Tsuda, T.; Yabuki, M.; Liu, Y.

    2014-12-01

    It is projected that localized extreme weather events could increase due to the effects of global warming, resulting in severe weather disasters, such as a torrential rain, floods, and so on. Understanding water vapor's behavior in the atmosphere is essen- tial to understand a fundamental mechanism of these weather events. Therefore, continuous monitoring system to measure the atmospheric water vapor with good spatio-temporal resolution is required. We have developed several water vapor Raman lidar systems employing the laser wavelengths of 355 and 532 nm. However, the signal-to-noise ratio of the Raman lidar strongly depends on the sky background because of the detection of the weak inelastic scattering of light by molecules. Therefore, these systems were mainly used during nighttime. Hence, we have newly developed a water vapor Raman lidar using a quadrupled Nd:YAG laser at a wavelength of 266 nm. This wavelength is in the ultraviolet (UV) range below 300 nm known as the "solar-blind" region, because practically all radiation at these wavelengths is absorbed by the ozone layer in the stratosphere. It has the advantage of having no daytime solar background radiation in the system. The lidar is equipped with a 25 cm receiving telescope and is used for measuring the light separated into an elastic backscatter signal and vibrational Raman signals of nitrogen and water vapor at wavelengths of 266.1, 283.6, and 294.6 nm, respectively. This system can be used for continuous water vapor measurements in the lower troposphere. This study introduces the design of the UV lidar system and shows the preliminary results of water vapor profiles.

  16. Biases in Total Precipitable Water Vapor Climatologies from Atmospheric Infrared Sounder and Advanced Microwave Scanning Radiometer

    NASA Technical Reports Server (NTRS)

    Fetzer, Eric J.; Lambrigtsen, Bjorn H.; Eldering, Annmarie; Aumann, Hartmut H.; Chahine, Moustafa T.

    2006-01-01

    We examine differences in total precipitable water vapor (PWV) from the Atmospheric Infrared Sounder (AIRS) and the Advanced Microwave Scanning Radiometer (AMSR-E) experiments sharing the Aqua spacecraft platform. Both systems provide estimates of PWV over water surfaces. We compare AIRS and AMSR-E PWV to constrain AIRS retrieval uncertainties as functions of AIRS retrieved infrared cloud fraction. PWV differences between the two instruments vary only weakly with infrared cloud fraction up to about 70%. Maps of AIRS-AMSR-E PWV differences vary with location and season. Observational biases, when both instruments observe identical scenes, are generally less than 5%. Exceptions are in cold air outbreaks where AIRS is biased moist by 10-20% or 10-60% (depending on retrieval processing) and at high latitudes in winter where AIRS is dry by 5-10%. Sampling biases, from different sampling characteristics of AIRS and AMSR-E, vary in sign and magnitude. AIRS sampling is dry by up to 30% in most high-latitude regions but moist by 5-15% in subtropical stratus cloud belts. Over the northwest Pacific, AIRS samples conditions more moist than AMSR-E by a much as 60%. We hypothesize that both wet and dry sampling biases are due to the effects of clouds on the AIRS retrieval methodology. The sign and magnitude of these biases depend upon the types of cloud present and on the relationship between clouds and PWV. These results for PWV imply that climatologies of height-resolved water vapor from AIRS must take into consideration local meteorological processes affecting AIRS sampling.

  17. ROCKETMAS: A sounding-rocket-based remote sensing measurement of mesospheric water vapor and ozone

    NASA Technical Reports Server (NTRS)

    Croskey, C. L.; Olivero, J. J.; Puliafito, S. E.; Mitchell, J. D.

    1994-01-01

    The ROCKETMAS rocketborne technique, based on the shuttle-borne millimeter wave atmospheric sounder (MAS), to obtain water vapor and ozone measurements with vertical resolution, is described. The concentrations of mesospheric water vapor and ozone are not well known, yet both contribute significantly to the chemical and radiative structure of that region. In situ measurements of water vapor are difficult to make because water that was absorbed on the instrument surfaces outgasses in space and contaminates the local environment of the payload. However, a remote sensing technique that uses a long pathlength through the atmosphere greatly reduces the effect of such local contamination. The 183.3 GHz line of water vapor and 184.4 GHz line of ozone are good choices for spaceborne radiometer measurements because one front-end mixer assembly can be used to simultaneously observe both gases. The design of a sounding rocket based millimeter wave radiometer for measuring water vapor and ozone with a height resolution not possible by either ground based or limb sounding techniques is described.

  18. Arctic cyclone water vapor isotopes support past sea ice retreat recorded in Greenland ice.

    PubMed

    Klein, Eric S; Cherry, J E; Young, J; Noone, D; Leffler, A J; Welker, J M

    2015-01-01

    Rapid Arctic warming is associated with important water cycle changes: sea ice loss, increasing atmospheric humidity, permafrost thaw, and water-induced ecosystem changes. Understanding these complex modern processes is critical to interpreting past hydrologic changes preserved in paleoclimate records and predicting future Arctic changes. Cyclones are a prevalent Arctic feature and water vapor isotope ratios during these events provide insights into modern hydrologic processes that help explain past changes to the Arctic water cycle. Here we present continuous measurements of water vapor isotope ratios (?(18)O, ?(2)H, d-excess) in Arctic Alaska from a 2013 cyclone. This cyclone resulted in a sharp d-excess decrease and disproportional ?(18)O enrichment, indicative of a higher humidity open Arctic Ocean water vapor source. Past transitions to warmer climates inferred from Greenland ice core records also reveal sharp decreases in d-excess, hypothesized to represent reduced sea ice extent and an increase in oceanic moisture source to Greenland Ice Sheet precipitation. Thus, measurements of water vapor isotope ratios during an Arctic cyclone provide a critical processed-based explanation, and the first direct confirmation, of relationships previously assumed to govern water isotope ratios during sea ice retreat and increased input of northern ocean moisture into the Arctic water cycle. PMID:26023728

  19. Water and oxygen permeation of silicon nitride films prepared by plasma-enhanced chemical vapor deposition

    Microsoft Academic Search

    D. S. Wuu; W. C. Lo; C. C. Chiang; H. B. Lin; L. S. Chang; R. H. Horng; C. L. Huang; Y. J. Gao

    2005-01-01

    Silicon nitride (SiNx) films deposited on flexible polyethersulfone (PES) substrates by plasma-enhanced chemical vapor deposition (PECVD) have been investigated for water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) barrier applications. Details of the NH3\\/SiH4 flow ratio and chamber pressure effects on the SiNx\\/PES properties in terms of chemical bonding, transmittance, refractive index, deposition rate, adhesion, roughness, OTR and

  20. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the around in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 W/sq m per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  1. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 Wm(exp -2) per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  2. Absorption coefficients for water vapor at 193 nm from 300 to 1073 K

    NASA Technical Reports Server (NTRS)

    Kessler, W. J.; Carleton, K. L.; Marinelli, W. J.

    1993-01-01

    Measurements of the water absorption coefficient at 193 nm from 300 to 1073 K are reported. The measurements were made using broadband VUV radiation and a monochromator-based detection system. The water vapor was generated by a saturator and metered into a flowing, 99 cm absorption cell via a water vapor mass flow meter. The 193 nm absorption coefficient measurements are compared to room temperature and high temperature shock tube measurements with good agreement. The absorption can be parameterized by a nu3 vibrational mode reaction coordinate and the thermal population of the nu3 mode.

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

    Microsoft Academic Search

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

    2006-01-01

    Experimental determinations of mass and thermal accommodation coefficients alpham and alphat 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

  4. Forced Dispersion of Liquefied Natural Gas Vapor Clouds with Water Spray Curtain Application 

    E-print Network

    Rana, Morshed A.

    2011-02-22

    11.3 m vx and sx mass fraction of water vapor and pollutant z vertical direction (z is positive in the upward direction) m z* dimensionless vertical distance ? thermal diffusivity of the ground m2/s ? gravity parameter.... .................................................... 92 Fig. 40. Rate of momentum calculated at the nozzle tip ................................................. 93 Fig. 41. Upward water spray from a conical nozzle. ..................................................... 101 Fig. 42...

  5. The effect of global-scale divergent circulation on the atmospheric water vapor transport and maintenance

    NASA Technical Reports Server (NTRS)

    Chen, Tsing-Chang

    1988-01-01

    The detection, distribution, and dynamics of atmospheric water on Earth was examined. How the high levels of water vapor and precipitation that occur over the tropics during the monsoon season result from the development of a strong divergent atmospheric circulation is discussed.

  6. Herschel observations of cold water vapor and ammonia in protoplanetary disks

    NASA Astrophysics Data System (ADS)

    Hogerheijde, Michiel R.; Bergin, Edwin A.; Brinch, Christian; Cleeves, L. Ilsedore; Fogel, Jeffrey K. J.; Blake, Geoffrey A.; Dominik, Carsten; Lis, Dariusz C.; Melnick, Gary; Neufeld, David; Pani?, Olja; Pearson, John C.; Kristensen, Lars; Yíldíz, Umut A.; van Dishoeck, Ewine F.

    2012-03-01

    We present the results of a Herschel/HIFI study into the presence of cold water vapor in a sample of protoplanetary disks, carried out as part of the Guaranteed Time Key Program `Water in Star Forming Regions with Herschel' (WISH). While toward most disks only upper limits are obtained, rotational ground-state emission lines of ortho-H_2O and para-H_2O are clearly detected toward the disk of TW Hya. The detection of cold water vapor, extending to at least 115 AU, in this disk indicates the presence of a vast reservoir of water ice totalling ˜ 1028 g or thousands of Earth Oceans. Photodesorption by stellar ultraviolet radiation likely liberates a small amount of water vapor from icy grains. Significant settling of such icy grains toward the disk midplane is required to match the detected amount of water vapor. The water ortho-to-para ratio of 0.77 is significantly different from that observed in Solar System comets where a range of 1.5--3 is found. If this reflects the temperature regime of the water ice (formation), this finding suggests that long-range mixing of volatiles has occured in the Solar Nebula. The same Herschel/HIFI data also detect the emission of NH_3 in TW Hya's disk, and the implications of this finding are discussed.

  7. Measurements of water vapor and high clouds over the Tibetan Plateau with the Terra MODIS instrument

    Microsoft Academic Search

    Bo-Cai Gao; Ping Yang; Guang Guo; Seon K. Park; Warren J. Wiscombe; Baode Cheon

    2003-01-01

    The seasonal variations of water vapor and cirrus clouds over the Tibetan Plateau are investigated using the recently available Level 3 monthly-mean atmospheric data products with a 1° × 1° latitude-longitude grid. The data products are derived from the multichannel imaging data acquired with the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra Spacecraft. It is shown that the water

  8. Studies on passive remote sensing of vapor, liquid, and ice water paths

    Microsoft Academic Search

    L. Li; J. Vivekanandan; C. H. Chan; L. Tsang; J. N. Hwang

    1994-01-01

    Ground-based dual-channel radiometers can be used to monitor water vapor and cloud liquid water. Radiometers can provide measurements automatically and continuously. Westwater (1978) and Staelin (1966) investigated the microwave spectrum of the atmosphere and its sensitivities to atmospheric components and these investigations provided the basis for most radiometric retrieval methods. During their investigations, statistical tools were more or less utilized

  9. On the quality of the Nimbus 7 LIMS Version 6 water vapor profiles and distributions

    NASA Astrophysics Data System (ADS)

    Remsberg, E. E.; Natarajan, M.; Lingenfelser, G. S.; Thompson, R. E.; Marshall, B. T.; Gordley, L. L.

    2009-09-01

    This report describes the quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) water vapor (H2O) profiles of 1978/1979 that were processed with a Version 6 (V6) algorithm and archived in 2002. The V6 profiles incorporate a better knowledge of the instrument attitude for the LIMS measurements along its orbits, leading to improvements for its temperature profiles and for the registration of its water vapor radiances with pressure. As a result, the LIMS V6 zonal-mean distributions of H2O exhibit better hemispheric symmetry than was the case from the original Version 5 (V5) dataset that was archived in 1982. Estimates of the precision and accuracy of the V6 H2O profiles are developed and provided. Individual profiles have a precision of order 5% and an estimated accuracy of about 19% at 3 hPa, 14% at 10 hPa, and 26% at 50 hPa. Profile segments within about 2 km of the tropopause are often affected by emissions from clouds that appear in the finite field-of-view of the detector for the LIMS H2O channel. Zonally-averaged distributions of the LIMS V6 H2O are compared with those from the more recent Microwave Limb Sounder (MLS) satellite experiment for November, February, and May of 2004/2005. The patterns and values of their respective distributions are similar in many respects. Effects of a strengthened Brewer-Dobson circulation are indicated in the MLS distributions of the recent decade versus those of LIMS from 1978/1979. A tropical tape recorder signal is present in the 7-month time series of LIMS V6 H2O with lowest values in February 1979, and the estimated, annually-averaged "entry-level" H2O is 3.5 to 3.8 ppmv. It is judged that this historic LIMS water vapor dataset is of good quality for studies of the near global-scale chemistry and transport for pressure levels from 3 hPa to about 70 to 100 hPa.

  10. On the quality of the Nimbus 7 LIMS Version 6 water vapor profiles and distributions

    NASA Astrophysics Data System (ADS)

    Remsberg, E. E.; Natarajan, M.; Lingenfelser, G. S.; Thompson, R. E.; Marshall, B. T.; Gordley, L. L.

    2009-12-01

    This report describes the quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) water vapor (H2O) profiles of 1978/79 that were processed with a Version 6 (V6) algorithm and archived in 2002. The V6 profiles incorporate a better knowledge of the instrument attitude for the LIMS measurements along its orbits, leading to improvements for its temperature profiles and for the registration of its water vapor radiances with pressure. As a result, the LIMS V6 zonal-mean distributions of H2O exhibit better hemispheric symmetry than was the case from the original Version 5 (V5) dataset that was archived in 1982. Estimates of the precision and accuracy of the V6 H2O profiles are developed and provided. Individual profiles have a precision of order 5% and an estimated accuracy of about 19% at 3 hPa, 14% at 10 hPa, and 26% at 50 hPa. Profile segments within about 2 km of the tropopause are often affected by emissions from clouds that appear in the finite field-of-view of the detector for the LIMS H2O channel. Zonally-averaged distributions of the LIMS V6 H2O are compared with those from the more recent Microwave Limb Sounder (MLS) satellite experiment for November, February, and May of 2004/05. The patterns and values of their respective distributions are similar in many respects. Effects of a strengthened Brewer-Dobson circulation are indicated in the MLS distributions of the recent decade versus those of LIMS from 1978/79. A tropical tape recorder signal is present in the 7-month time series of LIMS V6 H2O with lowest values in February 1979, and the estimated, annually-averaged "entry-level" H2O is 3.5 to 3.8 ppmv. It is judged that this historic LIMS water vapor dataset is of good quality for studies of the near global-scale chemistry and transport for pressure levels from 3 hPa to about 70 to 100 hPa.

  11. On the Quality of the Nimbus 7 LIMS Version 6 Water Vapor Profiles and Distributions

    NASA Technical Reports Server (NTRS)

    Remsberg, E. E.; Natarajan, M.; Lingenfelser, G. S.; Thompson, R. E.; Marshall, B. T.; Gordley, L. L.

    2009-01-01

    This report describes the quality of the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) water vapor (H2O) profiles of 1978/79 that were processed with a Version 6 (V6) algorithm and archived in 2002. The V6 profiles incorporate a better knowledge of the instrument attitude for the LIMS measurements along its orbits, leading to improvements for its temperature profiles and for the registration of its water vapor radiances with pressure. As a result, the LIMS V6 zonal-mean distributions of H2O exhibit better hemispheric symmetry than was the case from the original Version 5 (V5) dataset that was archived in 1982. Estimates of the precision and accuracy of the V6 H2O profiles are developed and provided. Individual profiles have a precision of order 5% and an estimated accuracy of about 19% at 3 hPa, 14% at 10 hPa, and 26% at 50 hPa. Profile segments within about 2 km of the tropopause are often affected by emissions from clouds that appear in the finite field-of-view of the detector for the LIMS H2O channel. Zonally-averaged distributions of the LIMS V6 H2O are compared with those from the more recent Microwave Limb Sounder (MLS) satellite experiment for November, February, and May of 2004/2005. The patterns and values of their respective distributions are similar in many respects. Effects of a strengthened Brewer-Dobson circulation are indicated in the MLS distributions of the recent decade versus those of LIMS from 1978/79. A tropical tape recorder signal is present in the 7-month time series of LIMS V6 H2O with lowest values in February 1979, and the estimated, annually-averaged "entry-level" H2O is 3.5 to 3.8 ppmv. It is judged that this historic LIMS water vapor dataset is of good quality for studies of the near global-scale chemistry and transport for pressure levels from 3 hPa to about 70 to 100 hPa.

  12. Mobile lidar system for measurement of water vapor mixing ratio and ozone number density

    NASA Technical Reports Server (NTRS)

    Whiteman, D.

    1988-01-01

    The Water Vapor Lidar was modified and extended to make differential absorption measurements of ozone. Water vapor measurements make use of a weak molecular scattering process known as Raman scattering. It is characterized by a shift in wavelength of the scattered beam of light relative to the incident one. Some of the energy of the incident photon is converted to vibrational or rotational energy within the molecule leaving the scattered photon shifted to a slightly longer wavelength. When performing water vapor measurements, profiles are acquired of water vapor mixing ratio from near the ground to beyond 7 km every 2 minutes. By forming a color composite image of the individual profiles, the spatial and temporal evolution of water vapor is visible with vertical resolution of 75 to 150m and temporal resolution of 2 minutes. The ozone lidar is intended for use as a cross calibration facility for other stationary ozone lidar systems. The ozone measurement employs the technique known as differential absorption. The backscattered laser radiation from two different wavelengths is measured. Successful measurements of 308 nm returns were made from 80 km with an averaging period of 6 hours. Using these data and a standard atmosphere density curve, an ozone number density profile was made which agrees very well with the standard ozone curve between 20 and 40 km.

  13. Differential Absorption Measurements of Atmospheric Water Vapor with a Coherent Lidar at 2050.532 nm

    NASA Technical Reports Server (NTRS)

    Koch, Grady J.; Dharamsi, Amin; Davis, Richard E.; Petros, Mulugeta; McCarthy, John C.

    1999-01-01

    Wind and water vapor are two major factors driving the Earth's atmospheric circulation, and direct measurement of these factors is needed for better understanding of basic atmospheric science, weather forecasting, and climate studies. Coherent lidar has proved to be a valuable tool for Doppler profiling of wind fields, and differential absorption lidar (DIAL) has shown its effectiveness in profiling water vapor. These two lidar techniques are generally considered distinctly different, but this paper explores an experimental combination of the Doppler and DIAL techniques for measuring both wind and water vapor with an eye-safe wavelength based on a solid-state laser material. Researchers have analyzed and demonstrated coherent DIAL water vapor measurements at 10 micrometers wavelength based on CO2 lasers. The hope of the research presented here is that the 2 gm wavelength in a holmium or thulium-based laser may offer smaller packaging and more rugged operation that the CO2-based approach. Researchers have extensively modeled 2 um coherent lasers for water vapor profiling, but no published demonstration is known. Studies have also been made, and results published on the Doppler portion, of a Nd:YAG-based coherent DIAL operating at 1.12 micrometers. Eye-safety of the 1.12 micrometer wavelength may be a concern, whereas the longer 2 micrometer and 10 micrometer systems allow a high level of eyesafety.

  14. Simultaneous balloonborne measurements of stratospheric water vapor and ozone in the polar regions

    SciTech Connect

    Hofmann, D.J.; Oltmans, S.J. (NOAA, Boulder, CO (United States)); Deshler, T. (Univ. of Wyoming, Laramie (United States))

    1991-06-01

    Vertical profiles of stratospheric water vapor and ozone were measured together at McMurdo and South Pole Stations in Antarctica, and at Kiruna, Sweden, on several occasions during the austral spring of 1990 and the boreal winter of 1991. The Antarctic data indicated that major dehydration had occurred on a continental scale over the winter stratospheric cloud formation period leaving only 2 to 3 ppmv water vapor between 11 and 19 km. Measurements before and after movement of the boundary of the polar vortex across McMurdo detected increases in both water vapor and ozone in the 17 to 20 km region. This injected layer was still observed at South Pole Station a month later suggesting continental proportions. In early November, with the vortex still intact, South Pole measurements indicated a substantial degree of inhomogeneity in both water vapor and ozone in the lower stratosphere. In comparison, stratospheric water vapor measurements in the Arctic gave values of 4 to 5 ppmv indicating the absence of the gross stratospheric dehydration effects obvious in the Antarctic, and they did not reveal significant structure except on one occasion with very cold temperatures ({minus}90C) at 25 km and nacreous cloud displays.

  15. What Can Water Vapor Reveal About Past and Future Climate Change?

    NASA Astrophysics Data System (ADS)

    Sherwood, Steven C.; Andronova, Natalia; Fetzer, Eric; Kursinski, E. Robert

    2009-04-01

    AGU Chapman Conference on Water Vapor and Its Role in Climate; Kailua-Kona, Hawaii, 20-24 October 2008; An AGU Chapman Conference on water vapor was held in Hawaii with approximately 120 attendees from nine countries. The meeting began with a keynote presentation on the hydrological cycle and climate change and continued with sessions on issues related to the upper troposphere/lower stratosphere region (UT/LS), the interactions of convection and water vapor, and the behavior of water vapor on large scales and in future and past climates. The conference highlighted important advances in the scientific community's understanding since the previous Chapman Conference on this subject, in 1999. Basic understanding of the future hydrological cycle changes predicted by the current generation of numerical climate models has improved significantly, owing to analyses of the Coupled Model Intercomparison Project phase 3 (CMIP3) archive of model outputs, helping to guide future research. Speakers also presented evidence of much weaker and stronger hydrological cycles at the Last Glacial Maximum (about 20,000 years ago) and hot periods in the early Eocene (55 million to 33 million years ago), respectively. While no evidence was presented to question the anticipated positive feedback of water vapor on global warming, discussions noted the expectation of local changes in relative humidity in a warmer climate.

  16. A Robust Retrieval of Water Vapor Column In Dry Arctic Conditions Using the Rotating Shadowband Spectroradiometer

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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) that was deployed during an intensive observation period near Barrow, Alaska, in March 1999. A line-by-line radiative transfer model was used to compute water vapor transmittance. The retrievals with this method are compared with retrievals obtained from three independent measurements with microwave radiometers. All four measurements show the same pattern of temporal variations. The RSS results agree most closely with retrievals obtained with the millimeter-wave imaging radiometer (MIR) at its 183 GHz +/- 7 double-side band channel. Their correlation over a period of 7 days when water vapor column varied between 0.75 mm and 3.6 mm (according to RSS) is 0.968 with MIR readings 0.12 mm higher on average.

  17. Assimilating GOES Brightness Temperatures. Part II: Assigning Water Vapor Wind Heights Directly from Weighting Functions.

    NASA Astrophysics Data System (ADS)

    Raymond, William H.; Wade, Gary S.; Zapotocny, Tom H.

    2004-08-01

    An unsolved problem with water vapor wind estimates from the upper-tropospheric 6.7-?m water vapor band on the Geostationary Operational Environmental Satellite (GOES) Imager (channel 3) is its exact placement in the vertical column. Satellite water vapor observations are known to be depth-averaged assessments of the upper-tropospheric moisture. Details about the effective averaging of upper-tropospheric observations, valid for GOES or those of other satellite platforms, are not retrieved as part of the observation. However, details about the vertical placement can be accurately estimated from forward radiative models that mimic the instrument spectral characteristics. A new method has been developed to assimilate satellite radiances or brightness temperatures directly into a numerical forecast model. A by-product of the new scheme is knowledge of the weighting functions that describe the assignment value given to each vertical layer. As a consequence, given water vapor wind data, these weighting functions allow the guessed wind field to be “intelligently” modified. In this study the vertical and horizontal characteristics of these weighting functions are examined. Statistics for a 16-day period are presented that show how weighted average wind components from the initial model forecast fields, computed using the weighting functions, compare with GOES water vapor wind observations.


  18. Raman lidar profiling of water vapor and aerosols over the ARM SGP Site

    SciTech Connect

    Ferrare, R.A.

    2000-01-09

    The authors have developed and implemented automated algorithms to retrieve profiles of water vapor mixing ratio, aerosol backscattering, and aerosol extinction from Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar data acquired during both daytime and nighttime operations. The Raman lidar sytem is unique in that it is turnkey, automated system designed for unattended, around-the-clock profiling of water vapor and aerosols. These Raman lidar profiles are important for determining the clear-sky radiative flux, as well as for validating the retrieval algorithms associated with satellite sensors. Accurate, high spatial and temporal resolution profiles of water vapor are also required for assimilation into mesoscale models to improve weather forecasts. The authors have also developed and implemented routines to simultaneously retrieve profiles of relative humidity. These routines utilize the water vapor mixing ratio profiles derived from the Raman lidar measurements together with temperature profiles derived from a physical retrieval algorithm that uses data from a collocated Atmospheric Emitted Radiance Interferometer (AERI) and the Geostationary Operational Environmental Satellite (GOES). These aerosol and water vapor profiles (Raman lidar) and temperature profiles (AERI+GOES) have been combined into a single product that takes advantage of both active and passive remote sensors to characterize the clear sky atmospheric state above the CART site.

  19. RAMAN LIDAR PROFILING OF WATER VAPOR AND AEROSOLS OVER THE ARM SGP SITE.

    SciTech Connect

    FERRARE,R.A.

    2000-01-09

    We have developed and implemented automated algorithms to retrieve profiles of water vapor mixing ratio, aerosol backscattering, and aerosol extinction from Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) Raman Lidar data acquired during both daytime and nighttime operations. This Raman lidar system is unique in that it is turnkey, automated system designed for unattended, around-the-clock profiling of water vapor and aerosols (Goldsmith et al., 1998). These Raman lidar profiles are important for determining the clear-sky radiative flux, as well as for validating the retrieval algorithms associated with satellite sensors. Accurate, high spatial and temporal resolution profiles of water vapor are also required for assimilation into mesoscale models to improve weather forecasts. We have also developed and implemented routines to simultaneously retrieve profiles of relative humidity. These routines utilize the water vapor mixing ratio profiles derived from the Raman lidar measurements together with temperature profiles derived from a physical retrieval algorithm that uses data from a collocated Atmospheric Emitted Radiance Interferometer (AERI) and the Geostationary Operational Environmental Satellite (GOES) (Feltz et al., 1998; Turner et al., 1999). These aerosol and water vapor profiles (Raman lidar) and temperature profiles (AERI+GOES) have been combined into a single product that takes advantage of both active and passive remote sensors to characterize the clear sky atmospheric state above the CART site.

  20. Treatment of Produced Water Using a Surfactant Modified Zeolite/Vapor Phase Bioreactor System

    SciTech Connect

    Lynn E. Katz; Kerry A. Kinney; Robert S. Bowman; Enid J. Sullivan; Soondong Kwon; Elaine B. Darby; Li-Jung Chen; Craig R. Altare

    2006-01-31

    Co-produced water from the oil and gas industry accounts for a significant waste stream in the United States. Produced waters typically contain a high total dissolved solids content, dissolved organic constituents such as benzene and toluene, an oil and grease component as well as chemicals added during the oil-production process. It has been estimated that a total of 14 billion barrels of produced water were generated in 2002 from onshore operations (Veil, 2004). Although much of this produced water is disposed via reinjection, environmental and cost considerations can make surface discharge of this water a more practical means of disposal. In addition, reinjection is not always a feasible option because of geographic, economic, or regulatory considerations. In these situations, it may be desirable, and often necessary from a regulatory viewpoint, to treat produced water before discharge. It may also be feasible to treat waters that slightly exceed regulatory limits for re-use in arid or drought-prone areas, rather than losing them to reinjection. A previous project conducted under DOE Contract DE-AC26-99BC15221 demonstrated that surfactant modified zeolite (SMZ) represents a potential treatment technology for produced water containing BTEX. Laboratory and field experiments suggest that: (1) sorption of benzene, toluene, ethylbenzene and xylenes (BTEX) to SMZ follows linear isotherms in which sorption increases with increasing solute hydrophobicity; (2) the presence of high salt concentrations substantially increases the capacity of the SMZ for BTEX; (3) competitive sorption among the BTEX compounds is negligible; and, (4) complete recovery of the SMZ sorption capacity for BTEX can be achieved by air sparging the SMZ. This report summarizes research for a follow on project to optimize the regeneration process for multiple sorption/regeneration cycles, and to develop and incorporate a vapor phase bioreactor (VPB) system for treatment of the off-gas generated during air sparging. To this end, we conducted batch and column laboratory SMZ and VPB experiments with synthetic and actual produced waters. Based on the results of the laboratory testing, a pilot scale study was designed and conducted to evaluate the combined SMZ/VPB process. An economic and regulatory feasibility analysis was also completed as part of the current study to assess the viability of the process for various water re-use options.

  1. Liquid-vapor fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature

    Microsoft Academic Search

    Juske Horita; David J. Wesolowski

    1994-01-01

    The equilibrium fractionation factors of oxygen and hydrogen isotopes between liquid water and water vapor have been precisely determined from 25 to 350°C on the VSMOW-SLAP scale, using three different types of apparatus with static or dynamic techniques for the sampling of water vapor. Our results for both oxygen and hydrogen isotope fractionation factors between 25 and 100°C are in

  2. Open air–vapor compression refrigeration system for air conditioning and hot water cooled by cool water

    Microsoft Academic Search

    Shaobo Hou; Huacong Li; Hefei Zhang

    2007-01-01

    This paper presents an open air–vapor compression refrigeration system for air conditioning and hot water cooled by cool water and proves its feasibility through performance simulation. Pinch technology is used in analysis of heat exchange in the surface heat exchanger, and the temperature difference at the pinch point is selected as 6°C. Its refrigeration depends mainly on both air and

  3. Intercomparison of Total Atmospheric Precipitable Water Vapor Retrieval Products during the 2009 and 2010 CAPABLE Summer Intensives

    NASA Astrophysics Data System (ADS)

    Pippin, M. R.; Knepp, T. N.; Bedka, S.; Cowen, L.; Murray, J.; Deslover, D.; Feltz, W.; Yesalusky, M. A.; Smith, W.; Cede, A.; Abuhassan, N.; Herman, J. R.; Szykamn, J.

    2011-12-01

    In support of NASA's GEO-CAPE mission and Air Quality Applied Sciences, the Chemistry and Physics Atmospheric Boundary Layer Experiment (CAPABLE) site at NASA Langley Research Center has been established in coordination with Environmental Protection Agency (EPA) and Virginia Department of Environmental Quality (VA DEQ) to assess the relationship between high temporal resolution measurements from space and continuous in situ surface observations. During the 2009 and 2010 CAPABLE summer intensives, three methods for determining total atmospheric precipitable water vapor were utilized. Continuous total column measurements of water vapor were provided using a Pandora spectrometer, the DOE/NSTec Atmospheric Sounder Spectrometer for Infrared Spectral Technology (ASSIST) operated by the Hampton University and the University of Wisconsin Atmospheric Emitted Radiance Interferometer (AERI). Continuous meteorological parameters were measured on a 5m tower and rawinsondes were launched intermittently throughout both measurement periods. We present preliminary results of the intercomparison of total precipitable water vapor from the three instrumental methods and compare with estimated values from dew point temperature and satellite overpass data. Results from this study will have applications to satellite validation and Pandora retrieval algorithm development. Disclaimer: Although this work was reviewed by the U.S. Environmental Protection Agency and National Aeronautics and Space Administration, and approved for publication, it may not necessarily reflect official Agency policy.

  4. The rate of water equilibration in vapor-diffusion crystallizations: dependence on the distance from the droplet to the reservoir.

    PubMed

    Luft, J R; Albright, D T; Baird, J K; DeTitta, G T

    1996-11-01

    The rate of water equilibration in hanging-drop vapor-diffusion experiments was studied as a function of the distance separating the hanging drop from the surface of the reservoir solution. Hanging drops of 1.00 M NaCl were allowed to partially equilibrate with reservoirs of 2.00 M NaCl at room temperature. Over the range of droplet-reservoir distances examined, 7.6-119.4 mm, the larger the distance that separated the droplet and reservoir, the slower the droplet equilibrated with the reservoir. The variation of the rate of equilibration with droplet-reservoir distance was non-linear; the rate was most sensitive to variations in the droplet-reservoir separation at short separations. A mathematical model of the equilibration kinetics was developed that fits the experimental data. The model is based on the assumption that the rate-limiting step in vapor-diffusion equilibration is transit of water across the vapor space. A simple device to vary the rate of water equilibration, and thereby optimize macromolecular crystal growth conditions, is described. PMID:15299569

  5. Retrieval of Atmospheric Water Vapor Density With Fine Spatial Resolution Using Three-Dimensional Tomographic Inversion of Microwave Brightness Temperatures Measured by a Network of Scanning Compact Radiometers

    Microsoft Academic Search

    Sharmila Padmanabhan; S. C. Reising; Jothiram Vivekanandan; Flavio Iturbide-Sanchez

    2009-01-01

    Quantitative precipitation forecasting is currently limited by the paucity of observations on sufficiently fine temporal and spatial scales. Three-dimensional water vapor fields can be retrieved with improved spatial coverage from measurements obtained using a network of scanning microwave radiometers. To investigate this potential, an observation system simulation experiment was performed in which synthetic examples of retrievals using a network of

  6. Alexandrite lidar for the atmospheric water vapor detection and development of powerful tunable sources in IR

    NASA Technical Reports Server (NTRS)

    Uchiumi, M.; Maeda, M.; Muraoka, K.; Uchino, O.

    1992-01-01

    New tunable solid-state lasers, such as alexandrite and Ti-sapphire lasers, provide a powerful technique to detect various molecules in the atmosphere whose absorption bands are in the infrared region. The differential absorption lidar (DIAL) system to measure the tropospheric water vapor has been investigated by many authors, in an early stage, by dye and ruby lasers. Using the alpha band of water vapor, the longest detection range can be obtained with high accuracy, and the alexandrite laser is the most suitable laser for this purpose. In this paper, we describe the detection of water vapor in the atmosphere by an alexandrite lidar, and the development of powerful tunable sources based on Raman lasers in the infrared region.

  7. Single Frequency, Pulsed Laser Diode Transmitter for Dial Water Vapor Measurements at 935nm

    NASA Technical Reports Server (NTRS)

    Switzer, Gregg W.; Cornwell, Donald M., Jr.; Krainak, Michael A.; Abshire, James B.; Rall, Johnathan A. R.

    1998-01-01

    We report a tunable, single frequency, narrow linewidth, pulsed laser diode transmitter at 935.68nm for remote sensing of atmospheric water vapor. The transmitter consists of a CW, tunable, external cavity diode laser whose output is amplified 2OdB using a tapered diode amplifier. The output is pulsed for range resolved DIAL lidar by pulsing the drive current to the diode amplifier at 4kHz with a .5% duty cycle. The output from the transmitter is 36OnJ/pulse and is single spatial mode. It maintains a linewidth of less than 25MHz as its wavelength is tuned across the water vapor absorption line at 935.68nm. The transmitter design and its use in a water vapor measurement will be discussed.

  8. High-resolution water vapor spectrum and line shape analysis in the Terahertz region

    NASA Astrophysics Data System (ADS)

    Slocum, David M.; Giles, Robert H.; Goyette, Thomas M.

    2015-07-01

    A coherent broadband high-resolution study of the water vapor absorption spectrum at 1.5 THz was performed. The transmittance was recorded for many different water vapor and air pressures at multiple path lengths at a resolution of 5-10 MHz. A post-processing routine was developed to filter the acquired data before being subjected to a global multispectral fitting analysis of 145 data sets. The experimental data was fit to multiple different line shapes and a line shape analysis was performed in order to determine the most accurate line shape in the Terahertz range. Five of the strongest water vapor lines in the region were identified and fit to the data. The line center frequencies, absolute intensities, self- and foreign-broadening coefficients, and self- and foreign-continuum coefficients were all experimentally determined along with their statistically determined error bars. The fitted parameters are compared to the values from the literature.

  9. Water vapor absorption spectrum measurements and its application in concentration measurement

    NASA Astrophysics Data System (ADS)

    Chang, Jun; Chen, Kun; Zhou, Guoqing; Lv, Guangping; Zhu, Cunguang; Wang, Zhongliang; Song, Fujun; Song, Haiyong; Tian, Junqiang; Hou, Wenjia; Huang, Jiaqing

    2012-02-01

    Wavelength tunable distributed feedback laser diode (DFB-LD) were utilized to measure line 1368.597nm and line 1367.862 nm absorption character of water vapor, based on it, water vapor concentration can be measured by peak absorption rate according to Beer-Lambert law. Besides, we observe that the overlap between the line 1368.597nm and line 1367.862 nm appears and become serious with the increase of gas pressure, this agrees well with the theoretical prediction, and the overlap cause difficulty to determine the absorption peak value, a scheme is presented to cope with the difficulty, it takes advantage of the peak absorption difference between 1368.597nm and 1367.862 nm, and the difference value is used to calculate the water-vapor concentration.

  10. Retrievals of Column Water Vapor Using Millimeter-Wave Radiometric Measurements

    NASA Technical Reports Server (NTRS)

    Wang, J. R.; Racette, P.; Triesky, M. E.; Manning, W.; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    Water vapor is one of the most important atmospheric constituents that has a critical impact on cloud formation (ice or liquid). It is also a source that needs to be accounted for in remote measurements of surface parameters. In the high-latitude regions, e.g., Antarctica, monitoring of the state of water vapor and its transport into and out of these regions is important towards our understanding the state of balance of ice sheets and its effect on the global sea level. The technique of retrieving low amount of column water vapor using the millimeter-wave radiometric measurements, as presented in this paper, will be very useful for these regions, especially during winter times when the atmosphere is relatively dry.

  11. The Effect of Water Vapor on Flame Velocity in Equivalent Carbon Monoxide and Oxygen Mixtures

    NASA Technical Reports Server (NTRS)

    Fiock, Ernest F; King, H Kendall

    1936-01-01

    This report presents the results of an investigation to study the effect of water vapor upon the spatial speed of flame in equivalent mixtures of carbon monoxide and oxygen at various total pressures from 100 to 780 mm.hg. These results show that, within this pressure range, an increase in flame speed is produced by increasing the mole fraction of water vapor at least as far as saturation at 25 degrees c., and that the rate of this increase is greater the higher the pressure. It is evident that water vapor plays an important part in the explosive oxidation of carbon monoxide; the need for further experimental evidence as to the nature of its action is indicated.

  12. Marangoni condensation of ammonia-water vapor mixtures on a horizontal tube

    NASA Astrophysics Data System (ADS)

    Dong, Bin; Zhao, Jun; Wang, Shixue

    2013-07-01

    In this paper, the Marangoni condensation of ammonia-water mixture on a horizontal smooth tube was investigated. The research presented here concerns the external condensation of down-flowing ammonia-water vapors on a 100mm long cooled horizontal copper tube of 16mm external diameter. The results showed that, with the change of the surface subcooling, the condensation heat transfer coefficients revealed nonlinear characteristics with peak values. With the increase of the ammonia vapor concentration, the condensation heat transfer coefficient decreased notably. The condensation heat transfer enhancement had been realized by addition of ammonia to water almost in all the experimental surface subcoolings. The maximum ratio of heat transfer coefficient compared to the pure steam is 1.9 at the ammonia vapor concentration of 0.38%.

  13. CVB: The Constrained Vapor Bubble 40 mm Capillary Experiment on the ISS

    NASA Technical Reports Server (NTRS)

    Wayner, Peter C., Jr.; Kundan, Akshay; Plawsky, Joel

    2013-01-01

    Discuss the Constrained Vapor Bubble (CVB) 40mm Fin experiment on the ISS and how it aims to achieve a better understanding of the physics of evaporation and condensation and how they affect cooling processes in microgravity using a remotely controlled microscope and a small cooling device

  14. A two-channel, tunable diode laser-based hygrometer for measurement of water vapor and cirrus cloud ice water content in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Thornberry, T. D.; Rollins, A. W.; Gao, R. S.; Watts, L. A.; Ciciora, S. J.; McLaughlin, R. J.; Fahey, D. W.

    2014-08-01

    The recently developed NOAA Water instrument is a two-channel, closed-path, tunable diode laser absorption spectrometer designed for the measurement of water vapor and enhanced total water (vapor + inertially enhanced condensed-phase) in the upper troposphere/lower stratosphere from the NASA Global Hawk unmanned aircraft system (UAS) or other high-altitude research aircraft. The instrument utilizes wavelength-modulated spectroscopy with second harmonic detection near 2694 nm to achieve high precision with a 79 cm double-pass optical path. The detection cells are operated under constant temperature, pressure and flow conditions to maintain a constant sensitivity to H2O independent of the ambient sampling environment. An on-board calibration system is used to perform periodic in situ calibrations to verify the stability of the instrument sensitivity during flight. For the water vapor channel, ambient air is sampled perpendicular to the flow past the aircraft in order to reject cloud particles, while the total water channel uses a heated, forward-facing inlet to sample both water vapor and cloud particles. The total water inlet operates subisokinetically, thereby inertially enhancing cloud particle number in the sample flow and affording increased cloud water content sensitivity. The NOAA Water instrument was flown for the first time during the second deployment of the Airborne Tropical TRopopause EXperiment (ATTREX) in February-March 2013 on board the Global Hawk UAS. The instrument demonstrated a typical in-flight precision (1 s, 1?) of better than 0.17 parts per million (ppm, 10-6 mol mol-1), with an overall H2O vapor measurement uncertainty of 5% ± 0.23 ppm. The inertial enhancement for cirrus cloud particle sampling under ATTREX flight conditions ranged from 33-48 for ice particles larger than 8 ?m in diameter, depending primarily on aircraft altitude. The resulting ice water content detection limit (2?) was 0.023-0.013 ppm, corresponding to approximately 2 ?g m-3, with an estimated overall uncertainty of 20%.

  15. Supercritical Water Mixture (SCWM) Experiment

    NASA Technical Reports Server (NTRS)

    Hicks, Michael C.; Hegde, Uday G.

    2012-01-01

    The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

  16. Numerical simulation of water vapor nucleation on electrically neutral nanoparticles

    SciTech Connect

    Shevkunov, S. V. [St. Petersburg State Polytechnic University (Russian Federation)], E-mail: root@svsh.tu.neva.ru

    2009-03-15

    Atomic-level Monte Carlo simulations are performed to calculate the free energy, entropy, and work of nucleation for clusters of more than 6 x 10{sup 3} water molecules growing on silver iodide crystalline particles of size up to 4 nm at a temperature of 260 K. The Hamiltonian of the system includes explicit expressions for hydrogen bonding energy and Coulomb, dispersion, exchange, and polarization interactions. The work of nucleation exhibits complex behavior depending on the nucleation-site size. With increasing nanoparticle size, clusters become less stable and the probability of crystallization increases. Mutual polarization enhances the bonding between a cluster and a crystalline particle. Cluster growth on relatively large nanoparticles involves two stages characterized by two critical sizes: monolayer growth on the surface and growth normal to the surface. Spontaneous microdroplet polarization involving domain formation is found to occur at the crystal surface. The dependence of the ice-forming activity of an aerosol on particulate size observed in experiments is explained by combined effects of several competing factors, the dominant ones being the stabilizing and destabilizing effects of the nanoparticle electric field.

  17. Interaction of gases with lunar materials. [surface properties of lunar fines, especially on exposure to water vapor

    NASA Technical Reports Server (NTRS)

    Holmes, H. F.; Gammage, R. B.

    1975-01-01

    The surface properties of lunar fines were investigated. Results indicate that, for the most part, these properties are independent of the chemical composition and location of the samples on the lunar surface. The leaching of channels and pores by adsorbed water vapor is a distinguishing feature of their surface chemistry. The elements of air, if adsorbed in conjunction with water vapor or liquid water, severely impedes the leaching process. In the absence of air, liquid water is more effective than water vapor in attacking the grains. The characteristics of Apollo 17 orange fines were evaluated and compared with those of other samples. The interconnecting channels produced by water vapor adsorption were found to be wider than usual for other types of fines. Damage tracks caused by heavy cosmic ray nuclei and an unusually high halogen content might provide for stronger etching conditions upon exposure to water vapor.

  18. GCM Simulation of the Large-Scale North American Monsoon Including Water Vapor Tracer Diagnostics

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Walker, Gregory; Schubert, Siegfried D.; Sud, Yogesh; Atlas, Robert M. (Technical Monitor)

    2002-01-01

    The geographic sources of water for the large scale North American monsoon in a GCM (General Circulation Model) are diagnosed using passive constituent tracers of regional water sources (Water Vapor Tracers, WVT). The NASA Data Assimilation Office Finite Volume (FV) GCM was used to produce a 10-year simulation (1984 through 1993) including observed sea surface temperature. Regional and global WVT sources were defined to delineate the surface origin of water for precipitation in and around the North American Monsoon. The evolution of the mean annual cycle and the interannual variations of the monsoonal circulation will be discussed. Of special concern are the relative contributions of the local source (precipitation recycling) and remote sources of water vapor to the annual cycle and the interannual variation of monsoonal precipitation. The relationships between soil water, surface evaporation, precipitation and precipitation recycling will be evaluated.

  19. GCM Simulation of the Large-scale North American Monsoon Including Water Vapor Tracer Diagnostics

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Walker, Gregory; Schubert, Siegfried D.; Sud, Yogesh; Atlas, Robert M. (Technical Monitor)

    2001-01-01

    The geographic sources of water for the large-scale North American monsoon in a GCM are diagnosed using passive constituent tracers of regional water'sources (Water Vapor Tracers, WVT). The NASA Data Assimilation Office Finite Volume (FV) GCM was used to produce a 10-year simulation (1984 through 1993) including observed sea surface temperature. Regional and global WVT sources were defined to delineate the surface origin of water for precipitation in and around the North American i'vionsoon. The evolution of the mean annual cycle and the interannual variations of the monsoonal circulation will be discussed. Of special concern are the relative contributions of the local source (precipitation recycling) and remote sources of water vapor to the annual cycle and the interannual variation of warm season precipitation. The relationships between soil water, surface evaporation, precipitation and precipitation recycling will be evaluated.

  20. Materials, methods and devices to detect and quantify water vapor concentrations in an atmosphere

    DOEpatents

    Allendorf, Mark D; Robinson, Alex L

    2014-12-09

    We have demonstrated that a surface acoustic wave (SAW) sensor coated with a nanoporous framework material (NFM) film can perform ultrasensitive water vapor detection at concentrations in air from 0.05 to 12,000 ppmv at 1 atmosphere pressure. The method is extendable to other MEMS-based sensors, such as microcantilevers, or to quartz crystal microbalance sensors. We identify a specific NFM that provides high sensitivity and selectivity to water vapor. However, our approach is generalizable to detection of other species using NFM to provide sensitivity and selectivity.