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1

Current status of the upcoming water vapor data sets from SAGE II and SAGE III experiments  

Microsoft Academic Search

The multi-year water vapor data set (version 5.9, covering January 1986 through May 1991) from the Stratospheric Aerosol and Gas Experiment II (SAGE II) played an important role in the SPARC Assessment of Upper Tropspheric and Stratospheric Water Vapor (WMO\\/TD No.1043, SPARC Report No.2; December 2000). Since then, revised SAGE II water vapor data sets, version 6.0 and version 6.1,

E. W. Chiou; W. P. Chu; L. W. Thomason; S. Burton

2003-01-01

2

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

Microsoft Academic Search

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

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

1998-01-01

3

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

NASA Astrophysics Data System (ADS)

Water vapor measurements made by the Halogen Occultation Experiment (HALOE) from 1991 to 1997 are compared with ground-based observations by the Water Vapor Millimeter-wave Spectrometers (WVMS) taken from 1992 to 1997 at Table Mountain, California (34.4°N, 242.3°E), and at Lauder, New Zealand (45.0°S, 169.7°E). The HALOE measurements show that an upward trend in middle atmospheric water vapor is present at all latitudes. The average trend in the HALOE water vapor retrievals at all latitudes in the 40-60 km range is 0.129 ppmv/yr, while the average trend observed by the WVMS instruments in this altitude range is 0.148 ppmv/yr. This trend is occurring below the altitude where changes in Lyman ? associated with solar cycle variations should produce a significant increase in water vapor during this period, and is much larger than the ˜0.02 ppmv/yr trend in water vapor associated with increases in methane entering the stratosphere. In addition to the water vapor increase, HALOE measurements show that there is a temporal decrease in methane at altitudes between 40 and 70 km. This indicates an increase in the conversion of the available methane to water vapor, thus contributing to the observed increase in water vapor. The increase in water vapor observed by both instruments is larger than that which would be expected from the sum of all of the above effects. We therefore conclude that there has been a significant increase in the amount of water vapor entering the middle atmosphere. A temperature increase of ˜0.1 K/yr in regions of stratosphere-troposphere exchange could increase the saturation mixing ratio of water vapor by an amount consistent with the observed increase.

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

1998-02-01

4

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

Microsoft Academic Search

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

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

1998-01-01

5

Seasonal variation of water vapor in the lower stratosphere observed in Halogen Occultation Experiment data  

Microsoft Academic Search

The seasonal cycle of water vapor in the lower stratosphere is studied based on Halogen Occultation Experiment (HALOE) satellite observations spanning 1991-2000. The seasonal cycle highlights fast, quasi-horizontal transport between tropics and midlatitudes in the lowermost stratosphere (near isentropic levels -380-420 K), in addition to vertical propagation above the equator (the tropical \\

William J. Randel; Fei Wu; Andrew Gettelman; J. M. Russell; Joseph M. Zawodny; Samuel J. Oltmans

2001-01-01

6

A revised water vapor product for the Stratospheric Aerosol and Gas Experiment (SAGE) II version 6.2 data set  

Microsoft Academic Search

The Stratospheric Aerosol and Gas Experiment (SAGE) II water vapor retrieval process has been updated to reflect a new understanding of the instrument performance. Primarily, this is reflected in a shifted spectral response for the primary water channel near 935 nm for the period after January 1986. In addition, the water vapor and ozone spectroscopy, aerosol clearing process, and error

Larry W. Thomason; Sharon P. Burton; Nina Iyer; Joseph M. Zawodny; John Anderson

2004-01-01

7

Comparison of Stratospheric Aerosol and Gas Experiment II and balloon-borne stratospheric water vapor measurements  

SciTech Connect

The Stratospheric Aerosol and Gas Experiment II has one channel at 940 nm related to water vapor. Two inversion procedures were developed independently in order to obtain the water vapor profile: the Chahine method by the Langley Research Center, and the Mill method by the Laboratoire d'Optique Atmospherique. Comparisons were made between these two algorithms and some results are presented at mid-latitudes ([approximately]45[degrees]N) and tropical latitudes (12[degrees]S-25[degrees]S). They are compared with in situ frost point hygrometer data provided by balloon experiments from the Laboratoire de Meteorologie Dynamique. At [plus minus]0.5 ppmv, agreement between the inversion results and the experimental results was obtained in the altitude range from 18-19 to 26-27 km. Below 18-19 km and above 26-27 km the error is larger (sometimes 1 ppmv and more). 17 refs., 4 figs.

Pruvost, P.; Lenoble, J. (Universite des Sciences et Techniques de Lille, Villeneuve d'Ascq (France)); Ovarlez, J. (Centre National de la Recherche Scientifique, Palaiseau (France)); Chu, W.P. (NASA Langley Research Center, Hampton, VA (United States))

1993-03-20

8

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

Microsoft Academic Search

This paper presents a description of the annual variations of water vapor in the stratosphere and the upper troposphere derived from observations of the Stratospheric Aerosol and Gas Experiment II (SAGE II). The altitude-time cross sections exhibit annually repeatable patterns in both hemispheres. The appearance of a yearly minimum in water vapor in both hemispheres at approximately the same time

M. P. McCormick; E. W. Chiou; L. R. McMaster; W. P. Chu; J. C. Larsen; D. Rind; S. Oltmans

1993-01-01

9

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

Microsoft Academic Search

Water vapor observations obtained from the Stratospheric Aerosol and Gas Experiment II (SAGE II) solar occultation instrument for the troposphere and stratosphere are presented and compared with correlative in situ measurement techniques and other satellite data. The SAGE II instrument produces water vapor values from cloud top to approximately 1 mbar, except in regions of high aerosol content such as

D. Rind; E.-W. Chiou; W. Chu; S. Oltmans; J. Lerner; J. Larsen; M. P. McCormick; L. McMaster

1993-01-01

10

Experiment on driving precipitable water vapor from ground-based GPS network in Chengdu Plain  

Microsoft Academic Search

The estimates of total zenith delay are derived using Bernese GPS Software V4. 2 based on GPS data every 30 s from the first\\u000a measurement experiment of a ground-based GPS network in Chengdu Plain of Southwest China during the period from July to September\\u000a 2004. Then the estimates of 0.5 hourly precipitable water vapor (PWV) derived from global positioning system

Guoping Li; Dingfa Huang; Biquan Liu; Jiaona Chen

2007-01-01

11

An Experiment for Estimation of the Spatial and Temporal Variations of Water Vapor Using GPS Data  

NASA Astrophysics Data System (ADS)

We have investigated the spatial and temporal variations of atmospheric water vapor using estimates of differential zenith wet delay. These estimates were obtained from an experiment involving Global Positioning System (GPS) receivers at five sites near Madrid, Spain. Data were acquired for 14 consecutive days in December 1996. The intersite horizontal separation varied from 5 km to 50 km (with a maximum altitude difference between sites of 400 m). The sampling rate for the GPS observations was 30 s, except for 2 days during which we used a sampling rate of 10 s. The GPS data were used to estimate relative zenith wet delays. One of the GPS receiving systems was colocated with a continuously operating dual-channel Water Vapor Radiometer (WVR). During the entire experiment the WVR obtained observations from a fixed pattern of directions intended to ``map'' the water-vapor distribution. We have found that these estimates of differential zenith wet delay are highly correlated with the altitude of the site and that the wet refractivity, on average, followed an exponential distribution with an assumed scale height of 1.5 km. We present results from this experiment, including the high degrees of correlation observed both in the spatial and temporal domains once the estimates of differential zenith wet delay were normalized after this exponential law.

Elósegui, P.; Rius, A.; Davis, J. L.; Ruffini, G.; Keihm, S.; Bürki, B.; Kruse, L. P.

12

An experiment for measuring the low temperature vapor line of water  

NASA Astrophysics Data System (ADS)

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

Velasco, S.; Faro, J.; Román, F. L.

2000-12-01

13

Constrained Vapor Bubble Experiment  

Microsoft Academic Search

Microgravity experiments on the Constrained Vapor Bubble Heat Exchanger, CVB, are being developed for the International Space Station. In particular, we present results of a precursory experimental and theoretical study of the vertical Constrained Vapor Bubble in the Earth's environment. A novel non-isothermal experimental setup was designed and built to study the transport processes in an ethanol\\/quartz vertical CVB system.

Shripad Gokhale; Joel Plawsky; Peter C. Wayner Jr.; Ling Zheng; Ying-Xi Wang

2002-01-01

14

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

15

Water Vapor and Cloud Detection Validation for Aqua Using Raman Lidars and AERI and the AWEX-G Validation Experiment  

Microsoft Academic Search

The early work in this investigation focused on the use of Raman lidar, ra- diosonde and AERI measurements for AIRS validation measurements as was reported in last year's annual report. That report revealed at times large unex- plained differences in various validation datasets being used forAIRS valida- tion. Because of this, the AIRS Water Vapor Experiment-Ground (AWEX-G) was proposed, funded

David Whiteman; Belay Demoz; Frank Schmidlin; Zhien Wang; Igor Veselovskii; Wallace McMillan; Ray Hoff; Felicita Russo; Scott Hannon; Larry Miloshevich; Barry Lesht; Gary Jedlovec; Madison WI; Martin Cadirola

16

Enceladus' water vapor plume.  

PubMed

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

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

2006-03-10

17

Water and Water Vapor Penetration Through Coatings  

Microsoft Academic Search

Water and water vapor transport in two-layer systems where one layer acts as water retarder are analyzed. In the experimental work, four external paints supposed to protect the underlying structure against water under common service conditions are applied on glass fiber reinforced concrete substrates. The water absorption coefficient and the effective water vapor diffusion coefficient are chosen as evaluation parameters

Jitka Podêbradská; Jaroslava Drchalová

2002-01-01

18

The atmospheric water vapor line  

Microsoft Academic Search

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

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

2008-01-01

19

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

NASA Astrophysics Data System (ADS)

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

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

1991-12-01

20

First UV satellite observations of mesospheric water vapor  

Microsoft Academic Search

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

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

2008-01-01

21

Water Vapor Diffusion Membrane Development.  

National Technical Information Service (NTIS)

A total of 18 different membranes were procured, characterized, and tested in a modified bench-scale vapor diffusion water reclamation unit. Four membranes were selected for further studies involving membrane fouling. Emphasis was placed on the problem of...

M. K. Tan

1976-01-01

22

Venus Balloons using Water Vapor  

Microsoft Academic Search

We propose an inflatable balloon using water vapor for the lifting gas, which is liquid in the transportation stage before entry into the high temperature atmosphere. The envelope of the balloon has an outer layer for gas barrier (a high-temperature resistant film) and an inner layer for liquid water keeping. In the descent stage using a parachute, water widely held

N. Izutsu; N. Yajima; H. Honda; T. Imamura

2002-01-01

23

On the Strength of Glass in Water Vapor  

Microsoft Academic Search

The bending strength of glass slides, which had the dimensions 38×6×0.16 mm, was measured at different relative pressures of water vapor. The adsorption isotherms of water vapor on powdered glass, which had the same composition as the slides, were measured in a separate experiment. The reduction of the surface free energy as function of the vapor pressure was calculated from

F. R. L. Schoening

1960-01-01

24

Single-droplet vapor-explosion experiments  

Microsoft Academic Search

Single-droplet vapor explosions on contact of hot molten material and a colder liquid are studied. In the five baseline experiments laser-melted iron-oxide droplets of about 0.1 gm at 1900°C are injected into a large water pool of about 4 kg at 15°C. As the molten iron-oxide droplet enters the water, stable film boiling is established. When a pressure pulse is

1987-01-01

25

The atmospheric water vapor line.  

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

26

Electrical Breakdown in Water Vapor  

NASA Astrophysics Data System (ADS)

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 (˜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.

Škoro, N.; Mari?, D.; Malovi?, G.; Graham, W. G.; Petrovi?, Z. Lj.

2011-11-01

27

Electrical Breakdown in Water Vapor  

SciTech Connect

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.

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

28

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

SciTech Connect

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

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

2005-05-01

29

Monolithic Microwave Integrated Circuit Water Vapor Radiometer.  

National Technical Information Service (NTIS)

A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valua...

L. M. Sukamto T. W. Cooley M. A. Janssen G. S. Parks

1991-01-01

30

Proposed reference model for middle atmosphere water vapor  

Microsoft Academic Search

Several new and significant satellite data sets on middle atmosphere water vapor have been produced recently. They include data from the Stratospheric Aerosol and Gas Experiment II (SAGE II) and the Nimbus-7 Stratospheric and Mesospheric Sounder (SAMS) experiment. The SAGE II data provide an estimate of interannual variability of water vapor in the stratosphere. The SAMS data are appropriate for

E. W. Chiou; E. E. Remsberg; C. D. Rodgers; R. Munro; R. M. Bevilacqua; M. P. McCormick; J RUSSELLIII

1996-01-01

31

Water vapor diffusion in Mars subsurface environments  

Microsoft Academic Search

The diffusion coefficient of water vapor in unconsolidated porous media is measured for various soil simulants at Mars-like pressures and subzero temperatures. An experimental chamber which simultaneously reproduces a low-pressure, low-temperature, and low-humidity environment is used to monitor water flux from an ice source through a porous diffusion barrier. Experiments are performed on four types of simulants: 40–70 ?m glass

Troy L. Hudson; Oded Aharonson; Norbert Schorghofer; Crofton B. Farmer; Michael H. Hecht; Nathan T. Bridges

2007-01-01

32

First UV satellite observations of mesospheric water vapor  

Microsoft Academic Search

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

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

2008-01-01

33

Validation of v1.022 mesospheric water vapor observed by the Solar Occultation for Ice Experiment instrument on the Aeronomy of Ice in the Mesosphere satellite  

Microsoft Academic Search

Water vapor measured by the Solar Occultation for Ice Experiment (SOFIE) instrument on the Aeronomy of Ice in the Mesosphere satellite has been validated in the vertical range 45–95 km. Precision estimates for SOFIE v1.022 H2O are ?0.2%–2.5% up to 80 km and degrade to ?20% at ?90 km. The SOFIE total systematic error from the retrieval analysis remains at

Pingping Rong; James M. Russell III; Larry L. Gordley; Mark E. Hervig; Lance Deaver; Peter F. Bernath; Kaley A. Walker

2010-01-01

34

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  

Microsoft Academic Search

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

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

2003-01-01

35

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

Microsoft Academic Search

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

Bruce M. Jakosky; Crofton B. Farmer

1982-01-01

36

Discovery of a water vapor layer in the Arctic summer mesosphere: Implications for polar mesospheric clouds  

Microsoft Academic Search

We report the discovery of a layer of enhanced water vapor in the Arctic summer mesosphere that was made utilizing two new techniques for remotely determining water vapor abundances. The first utilizes Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) OH measurements as a proxy for water vapor. The second is a reanalysis of Halogen Occultation Experiment (HALOE) water vapor data

Michael E. Summers; L. L. Gordley; M. J. McHugh

2001-01-01

37

Validation of POAM III Water Vapor using HALOE and MOZAIC  

Microsoft Academic Search

The Polar Ozone and Aerosol Measurement (POAM III) has been successfully measuring stratospheric water vapor since March 1998. High resolution vertical profile measurements are made on a daily basis in the Arctic and Antarctic regions. In this paper, the water vapor retrievals are validated by comparison with measurements from the Halogen Occultation Experiment (HALOE), and with Measurements of Ozone and

K. W. Hoppel; R. M. Bevilacqua; C. E. Randall; G. Nedoluha; J. D. Lumpe; H. Smit

2001-01-01

38

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

ERIC Educational Resources Information Center

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

Tellinghuisen, Joel

2010-01-01

39

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

ERIC Educational Resources Information Center

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

Tellinghuisen, Joel

2010-01-01

40

Water Vapor Sorption of Package Sealants  

Microsoft Academic Search

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

R. W. Vasofsky

1979-01-01

41

Venus Balloons using Water Vapor  

NASA Astrophysics Data System (ADS)

We propose an inflatable balloon using water vapor for the lifting gas, which is liquid in the transportation stage before entry into the high temperature atmosphere. The envelope of the balloon has an outer layer for gas barrier (a high-temperature resistant film) and an inner layer for liquid water keeping. In the descent stage using a parachute, water widely held just inside the balloon envelope can be quickly vaporized by a lot of heat flux from the surrounding high-temperature atmosphere owing to the large surface area of the balloon. As neither gas containers nor heat exchangers are necessary, we can construct a simple, lightweight and small size Venus balloon probe system. Tentative floating altitude is 35 km below the thick clouds in the Venusian atmosphere. Selection of balloon shape and material for balloon envelope are discussed in consideration of the Venusian environment such as high-temperature, high-pressure, and sulfuric acid. Balloon deployment and inflation sequence is numerically simulated. In case of the total floating mass of 10 kg at the altitude of 35 km, the volume and mass of the balloon is 1.5 cubic meters, and 3.5 kg, respectively. The shape of the balloon is chosen to be cylindrical with a small diameter. The mass of li fting gas can be determined as 4.3 kg and the remaining 2.2 kg becomes the payload mass. The mass of the total balloon system is also just 10 kg excluding the entry capsule.

Izutsu, N.; Yajima, N.; Honda, H.; Imamura, T.

42

CO2 DIAL measurements of water vapor  

Microsoft Academic Search

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

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

1987-01-01

43

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)

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.

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

2010-05-01

44

An atlas of extragalactic water vapor masers  

Microsoft Academic Search

We present an atlas of extragalactic water vapor masers. As of 2007, one hundred galaxies have been detected as sources of water vapor maser emission, two thirds of them discovered since 2003. Extragalactic water masers fall in at least three categories: those associated with nuclear jets or winds, those in starbursts or star-forming regions, and those in AGN accretion disks.

J. Braatz; P. Kondratko; L. Greenhill; J. Condon; C. Henkel; N. Gugliucci; L. Hao; M. Reid; J. Moran; K.-Y. Lo

2007-01-01

45

Broad band airborne water vapor radiometry  

NASA Astrophysics Data System (ADS)

An infrared radiometer with a pass band of 280 to 520 cm-1 (35.7 to 19.2 µm) is employed on the NASA Ames Research Center U-2 and C-141A aircraft in the measurement of water vapor burden in the upper troposphere and stratosphere. Coincidentally with altitude changes the water vapor mass mixing ratio is also inferred by observing the change in optical depth over a known vertical distance. Data from the December 1980 U-2 Water Vapor Exchange Experiment over the Panama Canal Zone adds to the concept that overshooting cumulonimbus towers “moisten” the lower stratosphere. The average mass mixing ratio in close proximity to or above such towers ranges from 3.5 to 5.0 parts per million above 18 km while the average background mass mixing ratio is only 2.9 parts per million. Generally the lowest background mixing ratios, averaging 2.6 parts per million occurred in the 18 to 21 km layer. For the same levels background Panama mass mixing ratios averaged from 1.0 to 3.0 parts per million higher than in middle latitudes.

Kuhn, Peter M.

46

The search for Water Vapor on Titan  

Microsoft Academic Search

The discovery of carbon dioxide on Titan in 1981 opened a new vista in the chemistry of reducing atmospheres. Because the principal mechanism for the production of carbon dioxide is the reaction of CO with the hydroxyl radical OH, a search began for both CO and water vapor at this time. Water vapor should be injected into Titan's atmosphere from

R. E. Samuelson; G. L. Bjoraker; A. Coustenis; Th. Encrenaz; A. Salama; Th. de Graauw

1997-01-01

47

Water vapor permeation in polyimide membranes  

Microsoft Academic Search

The study of the influence of water vapor in the feed stream of a mixed gas membrane separation system is of considerable practical importance. Water vapor may plasticize the membrane, it may undergo competitive sorption with other gas species and it can form clusters as it permeates. In this work, a modified mixed gas permeation system was employed to accurately

George Q. Chen; Colin A. Scholes; Greg G. Qiao; Sandra E. Kentish

2011-01-01

48

Modeling Water Vapor in the Upper Troposphere and Lower Stratosphere  

Microsoft Academic Search

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

Line Gulstad; Ivar S. A. Isaksen

2007-01-01

49

Observed seasonal to decadal scale responses in mesospheric water vapor  

Microsoft Academic Search

The 14 year (1991–2005) time series of mesospheric water vapor from the Halogen Occultation Experiment (HALOE) are analyzed using multiple linear regression (MLR) techniques for their seasonal and longer-period terms from 45°S to 45°N. The distribution of annual average water vapor shows a decrease from a maximum of 6.5 ppmv at 0.2 hPa to about 3.2 ppmv at 0.01 hPa,

Ellis Remsberg

2010-01-01

50

Water vapor retrieval over many surface types  

SciTech Connect

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

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

1996-04-01

51

Detection and Analysis of Water Vapor Transport  

NASA Astrophysics Data System (ADS)

Water vapor, though a minor constituent of Earth's atmosphere, plays a major role in the atmospheric radiation budget and the global water cycle. Atmospheric water vapor concentrations are highly variable due to the complex interplay between their sources (evaporation) and sinks (condensation and precipitation) in combination with transport and mixing. They strongly decrease with temperature and thus with altitude. Accurate measurement of water vapor is essential for better understanding its transport and cloud formation in the atmosphere and their impact on both weather and climate. To this end the institute develops and deploys lidars and in situ hygrometers onboard aircraft.

Kiemle, Christoph; Schäfler, Andreas; Voigt, Christiane

52

Tropical upper tropospheric water vapor distribution  

NASA Astrophysics Data System (ADS)

Water vapor is a powerful greenhouse gas and its fast response to temperature makes it a good candidates for creating feedback mechanisms that could modify global climate substantially. For one of the most important climate system on the Earth, the tropical climate system, it is particularly relevant because one of the major determinants has been identified as clear sky OLR averaged over the entire Tropics. Due to the radiative importance of water vapor in higher altitudes and drier regions, the major (but not exclusive) focus of our attention is the tropical upper tropospheric water vapor in the subsiding regions. Furthermore, the nonlinearity of Outgoing Longwave Radiation (OLR) responses to humidity entails a more detailed statistical analysis than zonally averaged humidity. The main vehicle to conduct this statistical analysis is Probability Distribution Function (PDF) of water vapor mixing ratio. The general task of this study is to investigate water vapor distribution, maintenance and radiative impacts, as well evaluation of General Circulation Model (GCM) water vapor performances. Previous research on water vapor maintenance had lead to Large Scale Advection hypothesis, which serves as the basis for our study. Traditional observation has been lacking in both coverage and accuracy, Tiros Observational Vertical Sounder (TOVS) water vapor data, assisted by more recent CEPEX tropical sounding, are employed in the data analysis. The observational chapter is devoted to the examination of the morphology, regional, seasonal variation and vertical variation of PDF, possible climate impact as well as the effects of resolution are also examined. Our data analysis shows that TOVS water vapor PDF has a skewed appearance. A linear transform procedure is shown to be able to bring PDF from different layer to a close fit. The mean and deviation of water vapor mixing ratio display a positive correlation. These information are further used to evaluate GCM water vapor performance. Similar data analysis procedures are performed on GCM water vapor PDF's and results are compared with TOVS counterparts. GCM PDF shows similar morphological features, but its capability in capturing the seasonality needs improvement. Our theoretical effort concentrates on two aspects. The initial PDF problem and the geometry of humidity distribution field The moist tail of humidity PDF is found to be influenced by the mixing ratio inside convective region and the mass flux into the subsiding region. It is also demonstrated that the combination of subsidence drying and stretching could result in a power law of water vapor concentration field.

Zhang, Hui

2002-09-01

53

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

Microsoft Academic Search

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

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

2004-01-01

54

CO(2) DIAL measurements of water vapor.  

PubMed

CO(2) lidars have heretofore been used to measure water vapor concentrations primarily using the 10R(20) line at 10.247 microm, which has a strong overlap with a water vapor absorption line. This paper discusses the use of that line as well as other CO(2) laser lines for which the absorption coefficients are weaker. The literature on measurement of water vapor absorption coefficients using CO(2) 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 coefficient for the 1P(14) CO(2) 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 CO(2) 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. PMID:20490006

Grant, W B; Margolis, J S; Brothers, A M; Tratt, D M

1987-08-01

55

Measuring Water Vapor with Differential Absorption Lidar  

NASA Astrophysics Data System (ADS)

Despite the need for global measurements of water vapor profiles with low bias and high vertical resolution there is currently no operational remote sensing system that would deliver such data. A possible solution to this problem is offered by the differential absorption lidar (DIAL) approach. The basic principle of operation will be described and some background on atmospheric light absorption by water vapor will be given. DLR's airborne water vapor DIAL system WALES represents the currently most advanced system worldwide using a multiwavelength technique to cover the troposphere and lower stratosphere simultaneously. A few examples of measurements made with this system will illustrate the power of this active remote sensing method.

Wirth, Martin

56

Hydrogen and water vapor adsorption on and reaction with uranium  

NASA Astrophysics Data System (ADS)

By combining modulated molecular beam scattering, temperature programmed desorption, and atomic force microscopy experiments, the fundamental properties of the interaction of hydrogen and water vapor with uranium at room temperature and above have been investigated. The initial sticking probability, hydride formation probabilities and desorption kinetics for dihydrogen and water vapor on clean uranium have been measured. In addition, saturation coverages for hydrogen and water vapor are determined for an initially clean uranium surface. Atomic force microscopy revealed site-specific initiation of hydride formation for slightly oxidized uranium at grain boundaries. The areal (and hence time) dependence of the hydride formation probability was also observed. The clean uranium surface is passivated significantly by oxidation and carburization. The sticking probabilities for dihydrogen and water vapor are one to two orders of magnitude smaller on oxidized and carbided surfaces. The carbided surface is efficiently produced by reaction of C60 with uranium surfaces between 600 and 800 K.

Balooch, M.; Hamza, A. V.

1996-06-01

57

Vapor burn analysis for the Coyote series LNG spill experiments  

SciTech Connect

A major purpose of the Coyote series of field experiments at China Lake, California, in 1981 was to study the burning of vapor clouds from spills of liquefied natural gas (LNG) on water. Extensive arrays of instrumentation were deployed to obtain micrometeorological, gas concentration, and fire-related data. The instrumentation included in situ sensors of various types, high-speed motion picture cameras, and infrared (IR) imagers. Five of the total of ten Coyote spill experiments investigated vapor burns. The first vapor-burn experiment, Coyote 2, was done with a small spill of LNG to assess instrument capability and survivability in vapor cloud fires. The emphasis in this report is on the other four vapor-burn experiments: Coyotes 3, 5, 6, and 7. The data are analyzed to determine fire spread, flame propagation, and heat flux - quantities that are related to the determination of the damage zone for vapor burns. The results of the analyses are given here. 20 references, 57 figures, 7 tables.

Rodean, H.C.; Hogan, W.J.; Urtiew, P.A.; Goldwire, H.C. Jr.; McRae, T.G.; Morgan, D.L. Jr.

1984-04-01

58

Mechanical Deterioration of Mgo by Water Vapor.  

National Technical Information Service (NTIS)

The effect of exposure to the laboratory atmosphere on the fracture stress and Young's modulus of polycrystalline magnesium oxide was studied. The observed degradation of mechanical properties was attributed to chemical attack by atmospheric water vapor. ...

K. R. Janowski R. C. Rossi

1967-01-01

59

Water vapor adsorption on geothermal reservoir rocks  

Microsoft Academic Search

The quantification of the amount of water retained in geothermal reservoir rocks allows a more realistic estimation of reserves for vapor-dominated geothermal reservoirs. If the measured desorption isotherm resembles the production characteristics of a geothermal system, understanding of the adsorption\\/desorption hysteresis will aid the design of reinjection processes.Adsorption\\/desorption isotherms of both nitrogen and water vapor on Berea sandstone and a

Shubo Shang; Roland N. Horne; Henry J. Ramey

1995-01-01

60

Proposed reference model for middle atmosphere water vapor  

NASA Astrophysics Data System (ADS)

Several new and significant satellite data sets on middle atmosphere water vapor have been produced recently. They include data from the Stratospheric Aerosol and Gas Experiment II (SAGE II) and the Nimbus-7 Stratospheric and Mesospheric Sounder (SAMS) experiment. The SAGE II data provide an estimate of interannual variability of water vapor in the stratosphere. The SAMS data are appropriate for the upper stratosphere and lower mesosphere. We combine these two data sets with those from the Nimbus-7 Limb Infrared Monitor of the Stratosphere (LIMS) experiment to update the COSPAR interim reference model for water vapor. Water vapor profiles from the Spacelab 3 Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment, ground-based microwave, and in situ balloon and aircraft measurements have been used to check the quality of the satellite data sets. The updated reference model is given as a function of latitude and pressure altitude and now covers all four seasons. Tabulations are included for these seasonal water vapor mixing ratios (in ppmv) and their estimated errors (in percent).

Chiou, E. W.; Remsberg, E. E.; Rodgers, C. D.; Munro, R.; Bevilacqua, R. M.; McCormick, M. P.; Russell, J. M.

61

Recent changes in lower stratospheric water vapor  

NASA Astrophysics Data System (ADS)

Increases have been noted in Northern Hemisphere middle latitude stratospheric water vapor over an extended period of time. However, over the past two years, a substantial decrease has been observed in tropical HALOE data in the 100-70 hPa layer. Similar decreases in the lower stratosphere are also seen in the frost point balloon observations taken by the NOAA Climate Monitoring and Diagnostics Laboratory in Boulder, Colorado, USA. (~40N) The decrease in water vapor appears to be the result of significant decreases in tropical tropopause temperatures as noted in assimilated model output (NCEP/NCAR reanalysis, UKMO/UARS analysis). There are also indications in the operational radiosonde data that there has been a decrease in tropical cold point temperatures. The recently observed decrease in lower stratospheric water vapor is confined vertically to pressures higher than 50 hPa. Increases are still apparent in water vapor in the middle and upper stratosphere as observed by HALOE and the Boulder water vapor sonde data. Possible changes in the mean meridional circulation will be presented as a mechanism to explain temporal changes in observed stratospheric water vapor.

Rosenlof, K.; Oltmans, S.; Randel, W.

2003-04-01

62

The Arm Program's Water Vapor Intensive Observation Periods  

Microsoft Academic Search

forward modeling) are continuing.The paper concludes by outlining the objectives of the recent 2000 WVIOP and the ARM-First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE) Water Vapor Experiment (AFWEX), the latter of which switched the focus to characterizing upper-tropospheric humidity measurements.

Henry E. Revercomb; David D. Turner; D. C. Tobin; Robert O. Knuteson; W. F. Feltz; James C. Barnard; J. Bösenberg; Shepard A. Clough; D. Cook; Richard Ferrare; John E M. Goldsmith; S. Gutman; R. N. Halthore; B. M. Lesht; James C. Liljegren; H. Linné; Joseph J. Michalsky; Victor R. Morris; William Porch; S. Richardson; B. Schmid; M. E. Splitt; T. van Hove; Ed R. Westwater; David N. Whiteman

2003-01-01

63

Modeling the effects of turbulence on water vapor radiometer measurements  

Microsoft Academic Search

A forward model for estimating the effects of atmospheric boundary layer turbulence on column-integrated water vapor is developed. This integrated water vapor can be estimated from water vapor microwave radiometric data. A potential inversion algorithm for estimating geophysical parameters from radiometer-derived integrated water vapor in turbulence is also discussed. Atmospheric turbulence is always present near the Earth's surface, and can

Justin Paul Bobak

1998-01-01

64

Numerical simulation of water injection into vapor-dominated reservoirs  

SciTech Connect

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

Pruess, K.

1995-01-01

65

Effect of Salt Additives to Water on the Severity of Vapor Explosions and on the Collapse of Vapor Film  

NASA Astrophysics Data System (ADS)

We proposed ultra rapid solidification and atomization technique, CANOPUS (Cooling and Atomizing based on NOble Process Utilizing Steam explosion), using small-scale vapor explosions to make an amorphous metal. The CANOPUS method is suitable for rapid cooling and atomization process, which utilizing sustainable small-scale vapor explosions. In order to apply the CANOPUS method to a high melting point metal, it is necessary to make a small-scale vapor explosion occur at a high temperature of the molten metal. Small-scale experiment is conducted to develop the vapor explosion promotor in which spontaneous vapor explosion can occur at a high temperature of a molten metal. Spontaneous vapor explosion do not occur when water at 80°C is used as a coolant. However, spontaneous vapor explosion occurs when water at 80°C with salt additives is used as a coolant. Specifically, lithium chloride solution generates spontaneous vapor explosions at the highest temperature of the molten tin in the experiment. In order to clarify the triggering mechanism of the spontaneous vapor explosion when the promotor is used as a coolant, a high-temperature solid stainless steel sphere is immersed into a coolant. The interfacial temperature of the stainless steel sphere is measured, and the behavior of a vapor film around the stainless steel sphere is observed with a digital video camera. As a result, salt additives resulted in an increase of quench temperature in all salt solutions. The quenching curves of each coolant indicate that the salt additives improve the film boiling heat transfer. The improvement of the film boiling heat transfer causes an unstable formation of the vapor film and a rise of the quench temperature. It is clarified that the salt additives to water promotes a vapor film collapse. Comparing two experiments, the quench temperature of each solution is in close agreement with the upper limit of the molten tin temperature that causes spontaneous vapor explosion. This result suggests that the vapor film collapse triggers spontaneous vapor explosion.

Arai, Takahiro; Furuya, Masahiro

66

DISTRIBUTION OF WATER VAPOR IN MOLECULAR CLOUDS  

SciTech Connect

We report the results of a large-area study of water vapor along the Orion Molecular Cloud ridge, the purpose of which was to determine the depth-dependent distribution of gas-phase water in dense molecular clouds. We find that the water vapor measured toward 77 spatial positions along the face-on Orion ridge, excluding positions surrounding the outflow associated with BN/KL and IRc2, display integrated intensities that correlate strongly with known cloud surface tracers such as CN, C{sub 2}H, {sup 13}CO J = 5-4, and HCN, and less well with the volume tracer N{sub 2}H{sup +}. Moreover, at total column densities corresponding to A{sub V}< 15 mag, the ratio of H{sub 2}O to C{sup 18}O integrated intensities shows a clear rise approaching the cloud surface. We show that this behavior cannot be accounted for by either optical depth or excitation effects, but suggests that gas-phase water abundances fall at large A{sub V}. These results are important as they affect measures of the true water-vapor abundance in molecular clouds by highlighting the limitations of comparing measured water-vapor column densities with such traditional cloud tracers as {sup 13}CO or C{sup 18}O. These results also support cloud models that incorporate freeze out of molecules as a critical component in determining the depth-dependent abundance of water vapor.

Melnick, Gary J.; Tolls, Volker [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Snell, Ronald L. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Bergin, Edwin A. [Department of Astronomy, University of Michigan, 825 Dennison Building, Ann Arbor, MI 48109 (United States); Hollenbach, David J. [SETI Institute, 515 North Whisman Road, Mountain View, CA 94043 (United States); Kaufman, Michael J. [Department of Physics and Astronomy, San Jose State University, One Washington Square, San Jose, CA 95192-0106 (United States); Li Di [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Neufeld, David A., E-mail: gmelnick@cfa.harvard.edu, E-mail: vtolls@cfa.harvard.edu, E-mail: snell@astro.umass.edu, E-mail: ebergin@umich.edu, E-mail: dhollenbach@seti.org, E-mail: mkaufman@email.sjsu.edu, E-mail: dili@jpl.nasa.gov, E-mail: neufeld@pha.jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

2011-01-20

67

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

SciTech Connect

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

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

2002-07-15

68

Monolithic microwave integrated circuit water vapor radiometer  

NASA Astrophysics Data System (ADS)

A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

1991-12-01

69

Specific heat of water vapor at high temperatures derived from explosion experiments. [2100 to 3100°K  

Microsoft Academic Search

The results of previous investigators are recalculated from their primary observations and compared. The possible effect of dissociation of hydrogen and water, possible inherent errors of the explosion method, and theoretical possibilities leading to higher-than-expected specific heats are discussed.

1930-01-01

70

The Vertical Distribution of Mars Water Vapor  

Microsoft Academic Search

Analysis of observations made from the Viking I Orbiter indicates that the water vapor over the Viking I landing site is uniformly mixed with the atmosphere and not concentrated near the surface. The analysis incorporates the effects of atmospheric scattering and explains why previous earth-based observations showed a strong diurnal variation in water content. It also explains the lack of

Donald W. Davies

1979-01-01

71

Role of Water Vapor in the Partial Oxidation of Propene  

Microsoft Academic Search

The role of water vapor was explored for the partial oxidation of propene over antimony–tin–vanadium oxide (SB\\/Sn\\/V oxide) catalyst at 1 atm pressure and 340°C using a microcatalytic packed bed reactor. Steady-state, transient kinetics, TPD, and isotopic transient experiments were performed. Water suppresses the formation of CO2by blocking the most active sites which are responsible for CO2formation but water also

Y. A. Saleh-Alhamed; R. R. Hudgins; P. L. Silveston

1996-01-01

72

Absorption cross sections for water vapor from 183 to 193 nm  

Microsoft Academic Search

Absorption cross sections for water vapor at 184.9 nm were measured using a standard low-pressure mercury lamp light source, optically filtered to isolate the spectral region near the emission line. The light from the source was detected using a solar-blind phototube. Experiments were performed over a wide range of water column amounts, using neat water vapor and water vapor\\/nitrogen mixtures,

Christopher A. Cantrell; Audrey Zimmer; Geoffrey S. Tyndall

1997-01-01

73

Stratospheric water vapor content evolution during EASOE  

SciTech Connect

This paper presents results of stratospheric water vapor measurements made from balloon borne instruments in the arctic winter as a part of EASOE. A frost-point hygrometer allowed measurement of the frost point and air temperature, which allowed the detection of conditions consistent with the formation of polar stratospheric clouds. Such clouds were observed on one occasion when this diagnostic sensed conditions conducive to the formation of such clouds. Outside the polar vortex the average water vapor density was fairly constant, between 4 to 5 ppmv between 16 and 25 km. More variation was observed both above and below these altitudes, and inside the vortex, vertical motion was also observed.

Ovarlez, J.; Overlez, H. (Laboratoire de Meteorologie Dynamique du CNRS, Palaiseau (France))

1994-06-22

74

Water vapor adsorption of ready-to-cook wheat  

Microsoft Academic Search

Water vapor adsorption of bulgur and hedik samples made from Triticum durum (Gediz 75) and Triticum aestivum (Panda) wheat were investigated. Experiments were conducted at 5, 15, 20, 30, and 40 °C for bulgur and at 20 °C for hedik samples between relative humidity (RH) of 11% and 100%. Bulgur samples became moldy before attaining equilibrium above 5 °C and

Mahir Turhan; Berrin Oymael; H. Ibrahim Ekiz

2003-01-01

75

Causes and Consequences of Mesospheric Water Vapor Layers  

NASA Astrophysics Data System (ADS)

Mesospheric observations from the UARS HALOE experiment have shown the existence of distinct water vapor layers both at low and at high latitudes. It has been speculated that the former are a consequence of heterogeneous chemistry acting on meteoric dust, whereas the latter are apparently associated with phase changes associated with the formation and evolution of polar mesospheric clouds. Further analysis of the HALOE water vapor observations suggest that there are two separate layers of enhanced water vapor at high latitudes and that there is a physical and/or chemical connection between the low latitude layer and the two high latitude layers. In this talk we will 1) use HALOE observations to characterize these mesospheric water vapor layers and their annual variation, 2) discuss the role of heterogeneous chemistry and surface/gas exchange on meteoric dust as a source of the lower altitude water vapor layer, and 3) explore the possibility that this altitude layer is causally connected to the formation and evolution of polar mesospheric clouds.

Summers, M. E.

2005-05-01

76

Stepwise changes in stratospheric water vapor?  

NASA Astrophysics Data System (ADS)

The sparse data available of stratospheric water vapor since the 1950s suggests a positive long-term trend that cannot be explained by the methane increase and what is known about temperature trends around the tropical tropopause, which constrain the amount of water entering the stratosphere. Here, we discuss the 1991-2005 time series of stratospheric water (and methane) measurements from the Halogen Occultation Experiment (HALOE). The high sampling, global coverage and measurement of methane render HALOE data ideal to check the data for self-consistency and to pinpoint the time of changes in entry mixing ratios. In addition to the well-known `drop' in October 2000, the HALOE data at 10 hPa and less suggest a steep increase in entry mixing ratios shortly before the beginning of the HALOE measurements. Model calculations using simple representations of the stratospheric age of air spectrum in the tropics show that the very dry phase may be explained by a range of scenarios: A long (several years) dry phase followed by a step increase with amplitude 0.3 ppmv; a shorter (?1 year) dry pulse with amplitude 0.6 ppmv; or steep linear trends over about 2 years with total increases similar to the step scenarios. The drop in October 2000 coincides with anomalously large eddy heat fluxes in the Southern hemisphere and low tropopause temperatures, but no such relation is found for the situation around 1991. The coincidence with the eruption of Mt. Pinatubo is discussed. The evidence for the results presented here is circumstantial, but they would imply that decoupling between stratospheric water trends and tropical tropopause temperatures can occur on short timescales.

Fueglistaler, S.

2012-07-01

77

Ground-based vapor crystal growth experiments  

NASA Astrophysics Data System (ADS)

We report on a novel computer-controlled experiment set-up for growing organic nonlinear optical (NLO) crystals by effusive- ampoule physical vapor transport (EAPVT). In this approach, incongruent or impurity vapor components are continuously removed from the vicinity of the growing crystal to vacuum. This results in considerably higher transport rates than are obtained in closed ampoule arrangements. As a consequence, crystal growth can be conducted with reduced temperature gradients, which is important for the growth of structurally perfect crystals. We present design considerations for an EAPVT apparatus, its construction, and its application to the growth of single crystals of 4-(N,N-dimethylamino)-3- acetamidonitrobenzene (DAN), an organic NLO material. The insight gained from this ground-based experimental work was used for the design of the flight hardware used aboard the U.S. Space Shuttle.

Zugrav, Maria I.; Rosenberger, Franz

1997-07-01

78

Tropical upper tropospheric water vapor distribution  

Microsoft Academic Search

Water vapor is a powerful greenhouse gas and its fast response to temperature makes it a good candidates for creating feedback mechanisms that could modify global climate substantially. For one of the most important climate system on the Earth, the tropical climate system, it is particularly relevant because one of the major determinants has been identified as clear sky OLR

Hui Zhang

2002-01-01

79

Use of Pointed Water Vapor Radiometer Observations to Improve Vertical GPS Surveying Accuracy.  

NASA Astrophysics Data System (ADS)

Atmospheric water vapor is a source of propagation delay, and therefore error, in Global Positioning System (GPS) geodesy. While GPS geodesy is now capable of millimeter level positioning, unmodelled water vapor can result in errors of several centimeters. Anisotropies in water vapor observed at ground sites have prompted the investigation into their effect upon GPS geodesy. Driven by the geophysical community's desire for more accurate baseline measurements, several previous attempts to improve geodesy with pointed water vapor radiometer (WVR) observations yielded dubious results. The development of an accurate, stable, steerable portable microwave water vapor radiometer, as well as improved oxygen and water vapor line shape models, has made possible more accurate water vapor measurements along the propagation paths to the GPS satellites. This radiometer development started in 1987 with funding from the Department of Commerce and still continues. This thesis will discuss the considerations relating to ionospheric and atmospheric refractivity (which induces phase delay in GPS signals) and to atmospheric microwave absorption (related to the microwave radiometer observable, emission). The microwave radiometer, its development, and its theoretical and measured performance characteristics are also described. Finally, a four month field experiment, called WVR92, is described wherein pointed water vapor radiometer observations were incorporated into modified GPS analysis software to correct for anisotropies in water vapor. A factor of two improvement was realized over stochastic methods and over zenith only WVR measurements. An interesting corollary finding resulted from this field experiment; it was found that, if the GPS position software were allowed to estimate the tropospheric water vapor by minimizing position residuals in a least squares sense, the zenith difference in water vapor burdens between GPS antenna locations could be measured to within a millimeter or so. Absolute water vapor burdens can be determined if WVR observations are taken at one of the GPS sites. This finding is of great interest to the meteorological community, and has triggered the installation of GPS receivers for water vapor measurements at meteorological network sites.

Solheim, Fredrick Stuart

80

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

SciTech Connect

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

Myers, B.F.

1995-09-01

81

SCIAMACHY lunar occultation water vapor measurements: retrieval and validation results  

NASA Astrophysics Data System (ADS)

SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) lunar occultation measurements have been used to derive vertical profiles of stratospheric water vapor for the Southern Hemisphere in the near infrared (NIR) spectral range of 1350-1420 nm. The focus of this study is to present the retrieval methodology including the sensitivity studies and optimizations for the implementation of the radiative transfer model on SCIAMACHY lunar occultation measurements. The study also includes the validation of the data product with the collocated measurements from two satellite occultation instruments and two instruments measuring in limb geometry. The SCIAMACHY lunar occultation water vapor measurement comparisons with the ACE-FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument have shown an agreement of 5% on the average that is well within the reported biases of ACE in the stratosphere. The comparisons with HALOE (Halogen Occultation Experiment) have also shown good results where the agreement between the instruments is within 5%. The validations of the lunar occultation water vapor measurements with MLS (Microwave Limb Sounder) instrument are exceptionally good, varying between 1.5 to around 4%. The validations with MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) are in the range of 10%. A validated dataset of water vapor vertical distributions from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of physical and chemical processes in the southern mid-latitudes and the dynamical processes related to the polar vortex.

Azam, F.; Bramstedt, K.; Rozanov, A.; Weigel, K.; Bovensmann, H.; Stiller, G. P.; Burrows, J. P.

2012-10-01

82

21 CFR 868.1975 - Water vapor analyzer.  

Code of Federal Regulations, 2013 CFR

...Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Diagnostic Devices § 868.1975 Water vapor analyzer. (a) Identification. A water vapor...

2013-04-01

83

Daytime Raman lidar profiling of atmospheric water vapor.  

National Technical Information Service (NTIS)

Detailed measurements of the distribution of water vapor in the atmosphere are needed for a variety of scientific inquiries, including global climate change and related issues in radiative processes (water vapor is the major greenhouse gas in the atmosphe...

J. E. M. Goldsmith S. E. Bisson

1994-01-01

84

Water vapor variability and comparisons in the subtropical Pacific from The Observing System Research and Predictability Experiment-Pacific Asian Regional Campaign (T-PARC) Driftsonde, Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), and reanalyses  

Microsoft Academic Search

During the THORPEX (The Observing System Research and Predictability Experiment) Pacific Asian Regional Campaign (T-PARC), from 1 August to 30 September 2008, ?1900 high-quality, high vertical resolution soundings were collected over the Pacific Ocean. These include dropsondes deployed from four aircrafts and zero-pressure balloons in the stratosphere (NCAR's Driftsonde system). The water vapor probability distribution and spatial variability in the

Junhong Wang; Liangying Zhang; Po-Hsiung Lin; Mark Bradford; Harold Cole; Jack Fox; Terry Hock; Dean Lauritsen; Scot Loehrer; Charlie Martin; Joseph VanAndel; Chun-Hsiung Weng; Kathryn Young

2010-01-01

85

Soil Vapor Extraction Column Experiments on Gasoline Contaminated Soil.  

National Technical Information Service (NTIS)

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

M. E. Miller T. A. Pedersen C. A. Kaslick G. E. Hoag C. Y. Fan

1992-01-01

86

Stable isotopic composition of water vapor in the tropics  

NASA Astrophysics Data System (ADS)

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.

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

87

Variability Of Atmospheric Water Vapor In The Martian Polar Regions  

Microsoft Academic Search

We present analysis of spatial and temporal variability of water vapor in the Mars Northern Polar Region (NPR) during spring and summer seasons using data from Vikings and MGS missions. This study provides a new level of detail on the Martian water vapor cycle relative to the previous longitudinally averaged studies. We also present new water vapor retrievals extending MGS

Alexey A. Pankine; L. K. Tamppari

2008-01-01

88

Solid state water vapor sensor for robotics applications  

Microsoft Academic Search

Preliminary results are presented on a solid-state water vapor sensor which is being considered for applications in robotics. The surface conductivity response produced by physical adsorption of water vapor on a glass surface used as the detection principle. A specific, sensitive, reversible conductivity response is observed at water vapor concentrations higher than 40% RH (relative humidity)

J. S. Kim; P. J. Reucroft

1988-01-01

89

Operating a radio-frequency plasma source on water vapor  

Microsoft Academic Search

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

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

2009-01-01

90

Effect of higher water vapor content on TBC performance  

SciTech Connect

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.

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

2012-01-01

91

Water vapor diffusion in Mars subsurface environments  

NASA Astrophysics Data System (ADS)

The diffusion coefficient of water vapor in unconsolidated porous media is measured for various soil simulants at Mars-like pressures and subzero temperatures. An experimental chamber which simultaneously reproduces a low-pressure, low-temperature, and low-humidity environment is used to monitor water flux from an ice source through a porous diffusion barrier. Experiments are performed on four types of simulants: 40-70 ?m glass beads, sintered glass filter disks, 1-3 ?m dust (both loose and packed), and JSC Mars-1. A theoretical framework is presented that applies to environments that are not necessarily isothermal or isobaric. For most of our samples, we find diffusion coefficients in the range of 2.8 to 5.4 cm2 s-1 at 600 Pascal and 260 K. This range becomes 1.9-4.7 cm2 s-1 when extrapolated to a Mars-like temperature of 200 K. Our preferred value for JSC Mars-1 at 600 Pa and 200 K is 3.7 +/- 0.5 cm2 s-1. The tortuosities of the glass beads is about 1.8. Packed dust displays a lower mean diffusion coefficient of 0.38 +/- 0.26 cm2 s-1, which can be attributed to transition to the Knudsen regime where molecular collisions with the pore walls dominate. Values for the diffusion coefficient and the variation of the diffusion coefficient with pressure are well matched by existing models. The survival of shallow subsurface ice on Mars and the providence of diffusion barriers are considered in light of these measurements.

Hudson, Troy L.; Aharonson, Oded; Schorghofer, Norbert; Farmer, Crofton B.; Hecht, Michael H.; Bridges, Nathan T.

2007-05-01

92

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

NASA Astrophysics Data System (ADS)

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.

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

2009-12-01

93

An Analysis of Airborne Measurements of Vertical Water Vapor Flux During BOMEX  

Microsoft Academic Search

The initial analysis of the water vapor flux measurements taken onboard a NOAA DC-6 during the Barbados Oceanographic and Meteorological Experiment (BOMEX) is presented. The flux of water vapor seems to be constant in the lower subcloud layer. Day-to-day variations, as well as variations within a day are apparent in the evaporation data. Spatial variations of evaporation also seem to

B. R. Bean; R. Gilmer; R. L. Grossman; R. McGavin; C. Travis

1972-01-01

94

Reaction rate constant for uranium in water and water vapor  

SciTech Connect

The literature on uranium oxidation in water and oxygen free water vapor was reviewed. Arrhenius rate equations were developed from the review data. These data and equations will be used as a baseline from which to compare reaction rates measured for K Basin fuel.

TRIMBLE, D.J.

1998-11-09

95

Implications of enhanced mesospheric water vapor observed by HALOE  

Microsoft Academic Search

Recently reprocessed water vapor data from the Halogen Occultation Experiment (HALOE) on the UARS satellite show significant deviations from the expected constant value of 2*CH4 + H2O. An unusual enhancement in the H2O is seen from 65–70 km which exceeds the stratospheric the value of 2*CH4 + H2O by 0.6–0.8 ppmv. This is inconsistent with the conventional view of transport

David E. Siskind; Michael E. Summers

1998-01-01

96

Implications of enhanced mesospheric water vapor observed by HALOE  

Microsoft Academic Search

Recently reprocessed water vapor data from the Halogen Occultation Experiment (HALOE) on the UARS satellite show significant deviations from the expected constant value of 2*CH4+H2O. An unusual enhancement in the H2O is seen from 65-70 km which exceeds the stratospheric the value of 2*CH4+H2O by 0.6-0.8 ppmv. This is inconsistent with the conventional view of transport of H2O and CH4

David E. Siskind; Michael E. Summers

1998-01-01

97

Diagnostics of land surface spatial variability and water vapor flux  

Microsoft Academic Search

To assess the spatial variability of the water vapor (i.e., latent heat) flux LE, it is convenient to scale it with its equilibrium analog LEe. From an analysis of the data from the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment, or FIFE, the spatial distribution of daily values of this dimensionless evaporation, alpha=LE\\/LEe, was found to be

Daoyi Chen; Wilfried Brutsaert

1995-01-01

98

Atmospheric water vapor complexes and the continuum  

NASA Astrophysics Data System (ADS)

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.

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

2004-03-01

99

Variability Of Atmospheric Water Vapor In The Martian Polar Regions  

NASA Astrophysics Data System (ADS)

We present analysis of spatial and temporal variability of water vapor in the Mars Northern Polar Region (NPR) during spring and summer seasons using data from Vikings and MGS missions. This study provides a new level of detail on the Martian water vapor cycle relative to the previous longitudinally averaged studies. We also present new water vapor retrievals extending MGS dataset over the North polar cap. Water vapor spatial distribution in the NPR evolves on short temporal (several sols) and small spatial (100 km) scales indicating complex interactions between surface/subsurface water ice and atmosphere. Similar average NPR abundances correspond to very different spatial patterns. Water vapor abundances observed by Vikings exceed MGS abundances by a factor of 2 during early summer, suggesting long term interannual variability of Martian polar water cycle. On the other hand, the difference between Viking and MGS observations may potentially be reconciled if water vapor is distributed non-uniformly with height, concentrating near surface. A reanalysis of Viking water vapor retrievals may be warranted. Much of the water vapor observed by Vikings during summer comes from the permanent polar cap, contrary to the earliest conclusion of the regolith being the main source. High degree of correlation between water vapor distribution and surface topography is probably due to interaction between mesoscale circulation and surface topography. Outbursts of water vapor are observed in late spring and summer, suggesting that water ice sublimation rates could be highly variable across the water ice cap, and strongly influenced by atmospheric circulation. Correlation between MGS water vapor and dust spatial distributions in NPR suggests sublimation winds as the source of both water vapor and dust in the atmosphere in late spring and summer. A historic record of the atmospheric water vapor at the Phoenix landing site is provided for comparison with ongoing observations.

Pankine, Alexey A.; Tamppari, L. K.

2008-09-01

100

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

NASA Astrophysics Data System (ADS)

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 the Global Network for Isotopes in Precipitation and collected during the African Monsoon Multidisciplinary Analysis field campaign, together with water-tagging experiments with the Laboratoire de Météorologie Dynamique general circulation model (LMDZ) fitted with isotopes. We show that some isotopic biases in LMDZ reveal the misrepresentation of dehydrating processes that would be undetected without isotopic measurements. In dry regions, the vapor isotopic composition is primarily controlled by the intensity of the air dehydration. In addition, it may also keep some memory of dehydration pathways that is erased in the humidity distribution, namely the relative contribution of dehydration in the tropical upper troposphere versus midlatitudes. In wet regions, vapor and rain isotope compositions are primarily controlled by changes in convection, through rain reevaporation and through the progressive depletion of the vapor by convective mixing along air mass trajectories. Gradients in vapor isotope composition along air mass trajectories may help estimate continental recycling intensity, provided that we could quantify the effect of convection on the isotopic composition of water vapor.

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

2010-12-01

101

Climatology and interannual variability of diurnal water vapor heating  

NASA Astrophysics Data System (ADS)

Tropospheric heating by water vapor insolation absorption is a leading drive of the propagating diurnal tide. A climatology of monthly diurnal radiative heating due to water vapor insolation absorption is derived using specific humidity from NCEP/NCAR reanalyses, and global precipitable water from the NASA Water Vapor Project. The new climatology complements and extends an existing one published by Groves in 1982 that provides seasonally averaged heating at tropical latitudes. The updated heating rates are of higher temporal and spatial resolution, and also enable an examination of year-to-year variability in water vapor heating over the 10-year span of the precipitable water dataset.

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

2001-12-01

102

Calibration of Atmospherically Induced Delay Fluctuations due to Water Vapor  

NASA Astrophysics Data System (ADS)

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

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

2000-05-01

103

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

National Technical Information Service (NTIS)

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

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

2009-01-01

104

Raman lidar profiling of atmospheric water vapor  

NASA Astrophysics Data System (ADS)

Detailed measurements of the distribution of water vapor in the atmosphere are needed for a variety of scientific inquiries, including global climate change and related issues in radiative processes (water vapor is the major greenhouse gas in the atmosphere), and studies of a variety of atmospheric processes such as cloud formation and atmospheric circulation. The Raman lidar is a leading candidate for an instrument capable of the detailed, time- and space-resolved measurements required by these and other studies. We are currently developing two Raman lidar systems. One, which has been under development for several years, is used for our own studies at Sandia. The Sandia lidar system uses an injection-seeded excimer laser to provide a beam with reduced divergence and spectral bandwidth, operated at 308 nm during both nighttime and daytime. The second Raman lidar system under development will have a permanent resident at the Department of Energy's Atmospheric Radiation Measurement program (ARM) Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma. This system is based on a high-power 355-nm laser beam produced by a frequency-tripled Nd:YAG laser.

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

1995-05-01

105

Testing Mixed-Phase Cloud Water Vapor Parameterizations with SHEBA\\/FIRE ACE Observations  

Microsoft Academic Search

The parameterization of in-cloud water vapor pressure below 0°C is examined using in situ aircraft observations from Canadian National Research Council (NRC) Convair-580 flights during the Surface Heat Budget of the Arctic Ocean (SHEBA)\\/First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment Arctic Cloud Experiment (FIRE ACE) campaign. The accuracy of in-cloud water vapor measurements is evaluated against the saturated

Qiang Fu; Shawn Hollars

2004-01-01

106

Interactions between aerosol, water vapor, and solar radiation  

NASA Astrophysics Data System (ADS)

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

Conant, William Christopher

107

Removal of Sarin Aerosol and Vapor by Water Sprays  

Microsoft Academic Search

Falling water drops can collect particles and soluble or reactive vapor from the gas through which they fall. Rain is known to remove particles and vapors by the process of rainout. Water sprays can be used to remove radioactive aerosol from the atmosphere of a nuclear reactor containment building. There is a potential for water sprays to be used as

Brockmann; John E

1998-01-01

108

Atmospheric measurements of water vapor in the 442-nm region  

Microsoft Academic Search

In recent years much interest has been generated in the atmospheric community concerning low resolution water vapor cross sections in the blue spectral region. Proper removal of water absorption from long path tropospheric and zenith sky stratospheric measurements has posed a significant problem for recovery of absorption spectra of low concentration molecular species which overlap the water vapor spectrum. The

J. W. Harder; J. W. Brault

1997-01-01

109

Stable isotope composition of water vapor as an indicator of transpiration fluxes from rice crops  

NASA Astrophysics Data System (ADS)

Measurements of the stable isotope composition (?2H and ?18O) of water vapor and associated micrometeorological parameters were made before and after full establishment of a rice crop in southeastern Australia. The aim of the experiment was to gain a better understanding of stable isotope variations of water vapor near the ground surface in response to local evaporation, local transpiration, regional scale vapor transport and the vertical stability of the atmospheric boundary layer. Vapor samples were collected at several heights within 9 m of the water surface during two separate sampling periods. The ?2H values of the water vapor ranged over more than 60‰, reflecting major rapid changes in regional air mass sources, as well as variations in the stability of the lowest 10 m of the atmosphere. The influence of tropical and higher-latitude air masses resulted in local vapor compositions which were relatively enriched and depleted, respectively, in heavy isotopes. Vertical gradients in heavy isotope abundances were very large during stable conditions (as much as ??2H = -27‰ from 0.8 to 8.4 m), as the result of mixing between transpired water and regional air vapor. Transpiration fluxes calculated from the water vapor ?2H gradient ranged from 5 to 7 mm d-1, which was in good agreement with one-dimensional aerodynamic energy budget calculations of daytime vapor fluxes.

Brunel, J. P.; Simpson, H. J.; Herczeg, A. L.; Whitehead, R.; Walker, G. R.

1992-05-01

110

Water Vapor Remote Sensing Techniques: Radiometry and Solar Spectrometry  

NASA Astrophysics Data System (ADS)

The high variability of atmospheric water vapor content plays an important role in space geodesy, climatology and meteorology. Water vapor has a strong influence on transatmospheric satellite signals, the Earth's climate and thus the weather forecasting. Several remote sensing techniques have been developed for the determination of inte- grated precipitable water vapor (IPWV). The Geodesy and Geodynamics Lab (GGL) utilizes the methods of Water Vapor Radiometry and Solar Spectrometry to quantify the amount of tropospheric water vapor and its temporal variations. The Water Vapor Radiometer (WVR) measures the radiation intensity of the atmosphere in a frequency band ranging from 20 to 32 GHz. The Solar Atmospheric MOnitoring Spectrome- ter (SAMOS) of GGL is designed for high-resolution measurements of water vapor absorption lines using solar radiation. In the framework of the ESCOMPTE (ExpÊrience sur Site pour COntraindre les Mod- Éles de Pollution atmosphÊrique et de Transport d'Emissions) field campaign these instruments have been operated near Marseille in 2001. They have aquired a long time series of integrated precipitable water vapor content (IPWV). The accuracy of IPWV measured by WVR and SAMOS is 1 kg/m2. Furthermore meteorological data from radiosondes were used to calculate the IPWV in order to provide comparisons with the results of WVR and SAMOS. The methods of Water Vapor Radiometry and So- lar Spectrometry will be discussed and first preliminary results retrieved from WVR, SAMOS and radiosondes during the ESCOMPTE field campaign will be presented.

Somieski, A.; Buerki, B.; Cocard, M.; Geiger, A.; Kahle, H.-G.

111

Potassium vapor topping cycle gas-fired boiler water test  

Microsoft Academic Search

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

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

1978-01-01

112

Profiling of atmospheric water vapor and liquid water with a K-band spectral radiometer  

NASA Astrophysics Data System (ADS)

This dissertation analyzes the retrieval of water vapor profiles via microwave radiometry; in particular it determines the information content of spectral data and identifies optimal measurement frequencies using an information content technique. The vertical resolution and estimate variance of water vapor profiles derived from the linear inversion of atmospheric data is examined and the effects of measurement noise on these quantities is considered. The Microwave Remote Sensing Laboratory at the University of Massachusetts has developed a unique K-Band Spectral Radiometer (KSR) system that simultaneously monitors eighteen frequencies near the 22.235 GHz water vapor absorption line and is designed to retrieve atmospheric water vapor density profiles by inverting spectral radiance measurements. This system is unique in its measurement speed and breadth. The dissertation discusses calibration techniques, system parameters, and the derivation of a statistical estimation algorithm is that is applied to KSR measurements taken during a field experiment in Lamont, Oklahoma. The resulting water vapor profiles are presented, along with a comparison of in- situ and independent observations.

Scheve, Timothy M.

1998-08-01

113

Water Vapor Enhancement in Prescribed Fire Plumes  

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

114

SOIL VAPOR EXTRACTION COLUMN EXPERIMENTS ON GASOLINE CONTAMINATED SOIL  

EPA Science Inventory

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

115

SOIL VAPOR EXTRACTION COLUMN EXPERIMENTS ON GASOLINE CONTAMINATED SOIL  

EPA Science Inventory

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

116

COLUMN VAPOR EXTRACTION EXPERIMENTS ON GASOLINE CONTAMINATED SOIL  

EPA Science Inventory

Soil vapor extraction (SVE) is a technique that is used to remove volatile organic compounds from unsaturated soils. ir is pumped from the contaminated area and the chemicals are removed from the resulting vapor stream. n this work laboratory, soil column experiments were conduct...

117

Operating a radio-frequency plasma source on water vapor.  

PubMed

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

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

2009-08-01

118

The role of water vapor feedback in unperturbed climate variability and global warming  

SciTech Connect

To understand the role of water vapor feedback in unperturbed surface temperature variability, a version of the Geophysical Fluid Dynamics Laboratory coupled ocean-atmosphere model is integrated for 1,000 yr in two configurations, one with water vapor feedback and one without. To understand the role of water vapor feedback in global warming, two 500-yr integrations were also performed in which CO{sub 2} was doubled in both model configurations. The final surface global warming in the model with water vapor feedback is 3.38 C, while in the one without it is only 1.05 C. However, the model`s water vapor feedback has a larger impact on surface warming in response to a doubling of CO{sub 2} than it does on internally generated, low-frequency, global-mean surface temperature anomalies. Water vapor feedback`s strength therefore depends on the type of temperature anomaly it affects. Finally, the authors compare the local and global-mean surface temperature time series from both unperturbed variability experiments to the observed record. The experiment without water vapor feedback does not have enough global-scale variability to reproduce the magnitude of the variability in the observed global-mean record, whether or not one removes the warming trend observed over the past century. In contrast, the amount of variability in the experiment with water vapor feedback is comparable to that of the global-mean record, provided the observed warming trend is removed. Thus, the authors are unable to simulate the observed levels of variability without water vapor feedback.

Hall, A. [Princeton Univ., NJ (United States). Atmospheric and Oceanic Sciences Program; Manabe, Syukuro [Geophysical Fluid Dynamics Lab., Princeton, NJ (United States)

1999-08-01

119

Water vapor as an active scalar in tropical atmospheric dynamics  

Microsoft Academic Search

Water vapor is a constituent of the tropical atmosphere which, though to a significant extent locally controlled by vertical advection, precipitation, and surface evaporation, is also affected by horizontal advection. Water vapor affects the flow in turn, because a humid atmosphere supports deep, precipitating convection more readily than a dry atmosphere. Precipitation heats the atmosphere, and this heating drives the

Adam H. Sobel

2002-01-01

120

Independent measurements of Raman LIDAR water vapor calibration factor  

Microsoft Academic Search

One of the goals of LIDAR scientists is to obtain long term monitoring of water vapor using Raman LIDAR [1]. Previous LIDAR research suggests that the measurement of water vapor can be improved by better analysis of the LIDAR system’s calibration factor. Currently LIDAR scientists generally use radiosonde data to calibrate LIDAR data. We are using a standard lamp calibration

M. N. Calhoun; D. D. Venable; D. N. Whiteman

2011-01-01

121

Aircraft Water Vapor Measurements Utilizing an Aluminum Oxide Hygrometer  

Microsoft Academic Search

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

Ernest Hilsenrath

1974-01-01

122

Diffusion characteristics of water vapor in some keratins  

Microsoft Academic Search

Summary A detailed examination of the diffusion behavior of water vapor in stratum corneum samples obtained from humans, guinea pig and neonatal rat, a well as in human air fibers, was carried out. It has been found that, as with most polymeric films above the glass transition temperature, diffusion of water vapor into stratum corneum and hair is characterized by

A. F. El-Shimi; H. M. Princen

1978-01-01

123

Active Raman sounding of the earth's water vapor field  

Microsoft Academic Search

The typically weak cross-sections characteristic of Raman processes has historically limited their use in atmospheric remote sensing to nighttime application. However, with advances in instrumentation and techniques, it is now possible to apply Raman lidar to the monitoring of atmospheric water vapor, aerosols and clouds throughout the diurnal cycle. Upper tropospheric and lower stratospheric measurements of water vapor using Raman

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

2005-01-01

124

Tropospheric odd nitrogen and the atmospheric water vapor cycle  

Microsoft Academic Search

A model for tropospheric odd nitrogen is presented. It is argued that the vertical profile of HNO3, a highly soluble gas, is similar to the vertical profile of water vapor, so that the volume mixing ratio of gaseous HNO3 to water vapor is constant with altitude. The value of this mixing ratio, deduced from the observed concentration of nitrates in

William Chameides

1975-01-01

125

Water Vapor Transmission Measurement and Significance of Corrections  

Microsoft Academic Search

Water vapor transmission properties of building materials play an important role in the overall moisture management and durability of the exterior building envelopes. The cup method, as described in the ASTM Standard Test Methods for Water Vapor Transmission of Materials (E 96), is widely used in North America and other parts of the world for this purpose. Recently the latest

Phalguni Mukhopadhyaya; Kumar Kumaran; John Lackey; David van Reenen; M. Kumaran; S. W. Dean

2007-01-01

126

Climate and Ozone Response to Increased Stratospheric Water Vapor.  

National Technical Information Service (NTIS)

Stratospheric water vapor abundance affects ozone, surface climate, and stratospheric temperatures. From 30-50 km altitude, temperatures show global decreases of 3-6 K over recent decades. These may be a proxy for water vapor increases, as the Goddard Ins...

D. T. Shindell

2001-01-01

127

High temperature corrosion of valve steels in atmosphere containing water vapor  

Microsoft Academic Search

The kinetics and mechanism of high temperature corrosion of two valve materials (X33CrNiMn23-8 and X50CrMnNiNbN21-9 steels)\\u000a in water-vapor-containing atmosphere have been studied as a function of temperature (973–1,273 K) and gas composition, being\\u000a the mixture of nitrogen, oxygen, and water vapor. In all experiments this atmosphere contained 50 vol.% of water vapor and\\u000a the concentration of oxygen was changed from 0.001 to

Z. Jurasz; K. Adamaszek; R. Janik; Z. Grzesik; S. Mrowec

2009-01-01

128

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

SciTech Connect

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.

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

2006-12-18

129

Eddy Transport of Water Vapor in the Martian Atmosphere.  

National Technical Information Service (NTIS)

Viking orbiter measurements of the Martian atmosphere suggest that the residual north polar water-ice cap is the primary source of atmospheric water vapor, which appears at successively lower northern latitudes as the summer season progresses. Zonally sym...

J. R. Murphy R. M. Haberle

1993-01-01

130

Catalytic combustion of styrene over copper based catalyst: inhibitory effect of water vapor.  

PubMed

The effects of water vapor on the activity of the copper based catalysts with different supports such as CuO/gamma-Al2O3, CuO/SiO2 and CuO/TiO2 for styrene combustion were investigated. The catalytic activity of the catalysts was tested in the absence of and presence of water vapor and the catalysts were characterized. Temperature programmed desorption (TPD) experiments and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS) measurements were conducted in order to estimate and explain the water effects. Results showed that the existence of water vapor had a significant negative effect on the catalytic activity of these copper based catalysts due to the competition adsorption of water molecule. DRIFTS studies showed that the catalyst CuO/gamma-Al2O3 had the strongest adsorption of water, while the catalyst CuO/TiO2 had the weakest adsorption of water. H2O-TPD studies also indicated that the order of desorption activation energies of water vapor on the catalysts or the strength of interactions of water molecules with the surfaces of the catalysts was CuO/gamma-Al2O3>CuO/SiO2>CuO/TiO2. As a consequence of that, the CuO/TiO2 exhibited the better durability to water vapor, while CuO/gamma-Al2O3 had the poorest durability to water vapor among these three catalysts. PMID:19427660

Pan, Hongyan; Xu, Mingyao; Li, Zhong; Huang, Sisi; He, Chun

2009-05-08

131

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

SciTech Connect

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

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

2009-07-01

132

Mercury isotope fractionation during liquid–vapor evaporation experiments  

Microsoft Academic Search

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

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

2009-01-01

133

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

Microsoft Academic Search

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

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

2009-01-01

134

ACA phase calibration scheme with the ALMA water vapor radiometers  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

135

Reactions of modulated molecular beams with pyrolytic graphite IV. Water vapor  

Microsoft Academic Search

The reaction of water vapor with the prism plane face of anneal pyrolytic graphite was investigated by modulated molecular beam-mass spectrometry methods. The equivalent water vapor pressure of the beam was ~2×10-5 Torr and the graphite temperature was varied from 300 to 2500°K. The mechanism was deduced from three types of experiments: isotope exchange utilizing modulated H2O and steady D2O

D. R. Olander; T. R. Acharya; A. Z. Ullman

1977-01-01

136

Reactions of modulated molecular beams with pyrolytic graphite IV. Water vapor  

Microsoft Academic Search

The reaction of water vapor with the prism plane face of anneal pyrolytic graphite was investigated by modulated molecular beam–mass spectrometry methods. The equivalent water vapor pressure of the beam was ?2×10?5 Torr and the graphite temperature was varied from 300 to 2500°K. The mechanism was deduced from three types of experiments: isotope exchange utilizing modulated H2O and steady D2O

D. R. Olander; T. R. Acharya; A. Z. Ullman

1977-01-01

137

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

Microsoft Academic Search

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

James Ryan Spackman

2004-01-01

138

Improved Water Vapor Measurement Using Water Vapor Radiometers and the Global Positioning System.  

NASA Astrophysics Data System (ADS)

Water vapor radiometer (WVR) retrieval algorithms require a priori information on atmospheric conditions along the line of sight of the radiometer to derive opacities from observed brightness temperatures. The mean radiating temperature of the atmosphere (T_{ rm mr}) is utilized in these algorithms to relate WVR measurements to integrated water vapor. Current methods for specifying T_{rm mr} rely on climatology, seasonal parameters, or information from nearby soundings to specify T _{rm mr}. However, values of T_{rm mr}, calculated from radiosonde data, vary not only according to site and season but also exhibit large fluctuations in response to local weather conditions. By utilizing output from numerical weather prediction models, T_ {rm mr} can be accurately prescribed for an arbitrary WVR site at a specific time. Values of T_{rm mr} obtained from current methods and this new approach are compared to those obtained from in situ soundings. The improvement of the T_{rm mr} calculation using available model forecast data rather than climatological values yields a corresponding improvement of comparable magnitude in the retrieval of atmospheric opacity. Use of forecast model data relieves a WVR site of its dependency on local climatology or the necessity of a nearby sounding, allowing more accurate retrieval of observed conditions and increased flexibility in choosing site location. Furthermore, it is found that the calculation of precipitable water by means of atmospheric opacities does not require time dependent tuning parameters when model data are used. The Global Positioning System (GPS) has been proposed as a source of meteorological information from which precipitable water values may be extracted from signal delays introduced by atmospheric water vapor. The utility of GPS derived precipitable water vapor measurements is demonstrated through the analysis of a mid-tropospheric cold front, or cold front aloft (CFA), which enhanced convection and resulted in severe thunderstorms during GPS-STORM. Surface based meteorological observations were insufficient for detecting and tracking the movement of the CFA, while vertical profiles obtained from the standard radiosonde observations lack the temporal and spatial resolution required to provide an adequate operational description of the feature which passed through the experimental domain midway between sounding times. Precipitable water measurements from GPS signals are shown to provide a valuable data source for operational forecasts as well as numerical weather prediction models.

Chiswell, Steven Rice

139

Climatology and interannual variability of diurnal water vapor heating  

Microsoft Academic Search

Tropospheric heating by water vapor absorption of near-infrared (IR) radiation is a leading drive of the propagating diurnal tide. A climatology of monthly diurnal water vapor IR heating rates is derived using National Centers for Environmental Prediction\\/National Center for Atmospheric Research (NCEP\\/NCAR) reanalysis and a global precipitable water (PW) data set. The new climatology updates an existing one compiled in

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

2003-01-01

140

Aircraft lidar sensitivity study for measuring water vapor  

NASA Astrophysics Data System (ADS)

The amount of water in the optical path between an airborne measurement platform and a target is responsible for the difference between the actual and the measurement target spectral radiance. In situ measurements of water vapor can be limited by outgassing from the sensor and/or its environment. A study was performed to investigate the use of lidar remote sensing techniques for the remote measurement of water vapor from a measurement aircraft such as the FISTA NKC-135A.

Rieder, R. J.; Shepherd, O.

1991-04-01

141

A latitudinal survey of mesospheric and upper stratospheric water vapor  

NASA Astrophysics Data System (ADS)

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

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

1994-09-01

142

A latitudinal survey of mesospheric and upper stratospheric water vapor  

NASA Astrophysics Data System (ADS)

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

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

1994-09-01

143

Water vapor absorption in the atmospheric window at 239 GHz  

NASA Astrophysics Data System (ADS)

Absolute absorption rates of pure water vapor and mixtures of water vapor and nitrogen have been measured in the atmospheric window at 239 GHz. The dependence on pressure as well as temperature has been obtained. The experimental data are compared with several theoretical or empirical models, and satisfactory agreement is obtained with the models involving a continuum; in the case of pure water vapor, the continuum contribution based upon recent theoretical developments gives good results. The temperature dependence is stronger than that proposed in a commonly used atmospheric transmission model.

Bauer, A.; Godon, M.; Carlier, J.; Ma, Q.

1995-04-01

144

Water-Vapor Pressure Control in a Volume.  

National Technical Information Service (NTIS)

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 diffusio...

J. J. Scialdone

1978-01-01

145

Specific heats of saturated water vapor and liquid  

NASA Astrophysics Data System (ADS)

This paper introduces a modification of the expression for the specific heat of saturated vapor attributed to Clausius and widely used in the literature. The proposed formula contains an additional term which avoids the often-criticized negative value of the specific heat of saturated vapor. Results are given for the case of water.

Elsner, Albrecht

1993-09-01

146

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

Microsoft Academic Search

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

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

1996-01-01

147

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

Microsoft Academic Search

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

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

1996-01-01

148

Effect of water vapor diffusion enhancement on soil moisture/temperature and evaporation - A numerical study  

NASA Astrophysics Data System (ADS)

Experimental and numerical studies concerning the coupled flow of liquid water and water vapor in porous media have shown differences in observed and Fickian diffusion-based modeled water vapor fluxes. Early studies explain these differences with evaporation-condensation effects in liquid islands in the variably saturated zone and enhanced water vapor flux due to local thermal gradients which differ between the different phases (air, water and solid) due to non-equilibrium effects at the pore scale. Consequently, an "enhancement factor" was introduced to correct for differences between model simulations and observations. Although widely used, recent studies question the existence of enhanced vapor diffusion because enhanced vapor-phase diffusion has never been measured or observed directly. In this contribution, we present results from numerical experiments in which we simulate coupled water and heat flow. The impact of the enhancement factor was evaluated by including or excluding it in the parameterization of the systems' properties. We designed three different model scenarios: one scenario with boundary conditions that represent field conditions and two scenarios representing different kinds of laboratory soil column experiments, to investigate under which conditions the impact of the enhancement factor could be observed in experiments. Finally, we tested with model simulations whether liquid water flow in films, which is not considered in the classical Mualem- van Genuchten parameterization of the hydraulic conductivity curve, can be an alternative explanation for larger than expected evaporation fluxes.

Steenpass, Christian; Vanderborght, Jan; Huisman, Johan Alexander

2010-05-01

149

Air-sea exchange of water vapor and sensible heat: The Humidity Exchange Over the Sea (HEXOS) results  

Microsoft Academic Search

Surface layer fluxes of sensible heat and water vapor were measured from a fixed-platform in the North Sea during the Humidity Exchange over the Sea (HEXOS) Main Experiment (HEXMAX). Eddy wind stress and other relevant atmospheric and oceanic parameters were measured simultaneously and are used to interpret the heat and water vapor flux results. One of the main goals of

J. DeCosmo; K. B. Katsaros; S. D. Smith; R. J. Anderson; W. A. Oost; K. Bumke; H. Chadwick

1996-01-01

150

Active Raman sounding of the earth's water vapor field.  

PubMed

The typically weak cross-sections characteristic of Raman processes has historically limited their use in atmospheric remote sensing to nighttime application. However, with advances in instrumentation and techniques, it is now possible to apply Raman lidar to the monitoring of atmospheric water vapor, aerosols and clouds throughout the diurnal cycle. Upper tropospheric and lower stratospheric measurements of water vapor using Raman lidar are also possible but are limited to nighttime and require long integration times. However, boundary layer studies of water vapor variability can now be performed with high temporal and spatial resolution. This paper will review the current state-of-the-art of Raman lidar for high-resolution measurements of the atmospheric water vapor, aerosol and cloud fields. In particular, we describe the use of Raman lidar for mapping the vertical distribution and variability of atmospheric water vapor, aerosols and clouds throughout the evolution of dynamic meteorological events. The ability of Raman lidar to detect and characterize water in the region of the tropopause and the importance of high-altitude water vapor for climate-related studies and meteorological satellite performance are discussed. PMID:16029854

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

2005-08-01

151

Effect of water vapor on the nucleation and growth of chemical vapor deposited copper films on spin-coated polyimide  

Microsoft Academic Search

The effect of water vapor on the mechanisms of nucleation and growth of metallo-organic chemical vapor deposited copper films from copper (II) hexafluoroacetylacetonate [Cu(hfa)2] on a polyimide substrate has been investigated. Minimal copper deposition was observed on the polyimide substrate in the absence of water vapor. When water vapor was introduced into the system, blanket copper deposition was observed on

Jung-Yeul Kim; H. A. Marzouk; P. J. Reucroft; C. C. Eloi; J. D. Robertson

1995-01-01

152

Water Vapor Differential Absorption LIDAR Design for Unpiloted Aerial Vehicles.  

National Technical Information Service (NTIS)

This system study proposes the deployment of a water vapor Differential Absorption LIDAR (DIAL) system on an Altair unmanned aerial vehicle (UAV) platform. The Altair offers improved payload weight and volume performance, and longer total flight time as c...

P. F. Mead R. J. DeYoung

2005-01-01

153

Water Vapor Influence on Satellite-Measured Aerosol Characteristics.  

National Technical Information Service (NTIS)

This study demonstrates the significance of water vapor's influence on satellite retrieved aerosol characteristics using NOAA's AVHRR. An improvement to optical depth and Aerosol Particle Size Index (S12) estimations derived from channels 1 (0.63 microns ...

T. P. Mahony

1991-01-01

154

Estimation of slant water vapor along GPS ray paths  

NASA Astrophysics Data System (ADS)

Slant water vapor (SWV) measurements along GPS ray paths have the potential to be useful in reconstructing three dimensional water vapor field, which is the key problem of GPS meteorology. A direct method of estimating SWV using GPS non-difference LC observation combinations without the effect of ionosphere. Comparing with Water Vapor Radiometer(WVR) measurements showed that it can get millimeter level accuracy of SWV estimated by this method every 30 seconds. The difference between the averages of SWV in 5 minutes after scaled to zenith and PWV estimated directly by GIPSY very 5 minutes is less than 2mm. SWV obtained by the this method can be used in tomography to sense the three dimensional structure of water vapor and improve the initial conditions of numerical weather forecast. It’s also useful in correcting the error of GPS geodesy and radar images.

Song, S. L.; Zhu, W. Y.; Cheng, Z. Y.; Liao, X. H.

2004-08-01

155

Weather and climate analyses using improved global water vapor observations  

NASA Astrophysics Data System (ADS)

The NASA Water Vapor Project (NVAP) dataset is a global (land and ocean) water vapor dataset created by merging multiple sources of atmospheric water vapor to form a global data base of total and layered precipitable water vapor. Under the NASA Making Earth Science Data Records for Research Environments (MEaSUREs) program, NVAP is being reprocessed and extended, increasing its 14-year coverage to include 22 years of data. The NVAP-MEaSUREs (NVAP-M) dataset is geared towards varied user needs, and biases in the original dataset caused by algorithm and input changes were removed. This is accomplished by relying on peer reviewed algorithms and producing the data in multiple “streams” to create products geared towards studies of both climate and weather. We briefly discuss the need for reprocessing and extension, steps taken to improve the product, and provide some early science results highlighting the improvements and potential scientific uses of NVAP-M.

Vonder Haar, Thomas H.; Bytheway, Janice L.; Forsythe, John M.

2012-08-01

156

Determination of Vibrational and Rotational Energy Levels of Water Vapor.  

National Technical Information Service (NTIS)

Water vapor absorbs energy in the infrared and invisible portions of the electromagnetic spectrum by two methods: Absorption of energy to increase its vibrational energy and/or absorption of energy to increase its rotational energy. Computer programs were...

D. L. Dobbins A. H. LaGrone

1967-01-01

157

Daytime Raman lidar profiling of atmospheric water vapor  

SciTech Connect

Detailed measurements of the distribution of water vapor in the atmosphere are needed for a variety of scientific inquiries, including global climate change and related issues in radiative processes (water vapor is the major greenhouse gas in the atmosphere), and studies of a variety of atmospheric processes such as cloud formation and atmospheric circulation. The Raman lidar is a leading candidate for an instrument capable of the detailed, time- and space-resolved measurements required by these and other studies.

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

1994-08-01

158

Lidar for the determination of Antarctic water vapor profiles  

NASA Astrophysics Data System (ADS)

A differential lidar technique was demonstrated to be capable of determining water vapor profiles in the Antarctic atmosphere in the vicinity of clear air ice crystal precipitation events. A Candela flashlamp-pumped, tunable dye laser operating in the 930-nm spectral region proved to be an appropriate source for the system. Application of this system to the measurement of low concentrations of water vapor, such as those which would be observed during Antarctic precipitation events, was demonstrated in the laboratory.

Whitcomb, Bruce Magill

159

Daytime Raman lidar profiling of atmospheric water vapor  

NASA Astrophysics Data System (ADS)

Detailed measurements of the distribution of water vapor in the atmosphere are needed for a variety of scientific inquiries, including global climate change and related issues in radiative processes (water vapor is the major greenhouse gas in the atmosphere), and studies of a variety of atmospheric processes such as cloud formation and atmospheric circulation. The Raman lidar is a leading candidate for an instrument capable of the detailed, time- and space-resolved measurements required by these and other studies.

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

160

The short-term temporal spectrum of precipitable water vapor.  

PubMed

Short-term power spectra of the fluctuations in the precipitable water vapor measured with a dual-channel microwave radiometer are presented. The spectra, taken over 34-hour sampling periods, encompass periodicities from I day to about 10 minutes. The fluctuation power is associated with the average precipitable water vapor for the sampling period. The background noise spectrum of the radiometric instrument is also discussed. PMID:17741100

Hogg, D C; Guiraud, F O; Sweezy, W B

1981-09-01

161

Sensing atmospheric water vapor with the Global Positioning System  

Microsoft Academic Search

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

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

1993-01-01

162

Smart temperature-controlled water vapor permeable polyurethane film  

Microsoft Academic Search

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

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

2007-01-01

163

Clouds and water vapor in the Northern Hemisphere summertime stratosphere  

Microsoft Academic Search

Cloud top observations from the Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) instrument and water vapor measured by the Microwave Limb Sounder (MLS) are used to study the occurrence of clouds in the Northern Hemisphere (NH) summertime lower stratosphere (20°?70°N) and their relation to water vapor. At low latitudes, clouds in the stratosphere tend to occur in regions of intense

A. E. Dessler

2009-01-01

164

Electrochemical vapor deposition - Theory and experiment  

NASA Astrophysics Data System (ADS)

The theory for the growth of ionically conducting Zr(Y)O(2-x) and electronically conducting LaCrO3 is discussed. Experimental parameters important to EVD (electrochemical vapor deposition) growth films of stabilized zirconia are presented. It is shown that in the modeling of the EVD growth of Zr(Y)O(2-x) it is important to consider the changes in the mole fractions of electrons and holes with Po2. At high temperatures only electrons need to be considered in EVD growth. At low temperatures the presence of holes at the metal/chloride interface may play an important role in the observed faceted morphology of EVD-grown Zr(Y)O(2-x). For the interconnect LaCrO3, ionic diffusion is rate limiting for EVD film growth and very high temperatures (1600 K) are necessary for moderate growth rates of 3 micron/h. Information on oxygen diffusion in doped LaCro3 is necessary for a more thorough understanding of the EVD growth.

Kiwiet, N. J.; Schoonman, J.

165

A WATER VAPOR MONITOR USING DIFFERENTIAL INFRARED ABSORPTION  

EPA Science Inventory

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

166

Reversibility of Water Vapor Sorption by Cottage Cheese Whey Solids  

Microsoft Academic Search

Desorption isotherms for water vapor from cottage cheese whey so,lids vary with the way water is first sorbed by the whey solids. When water is sorbed progressively in small increments be- tween zero pressure and saturation pres- sure, the powder becomes 'more porous during lactose crystallization. Subsequent desorption data follow a sigmoid pattern as a function of relative pressure. More

B. A. Anderson

1975-01-01

167

Water Vapor-Mediated Volatilization of High-Temperature Materials  

NASA Astrophysics Data System (ADS)

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

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

2013-07-01

168

Gas phase reaction of sulfur trioxide with water vapor  

SciTech Connect

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.

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

1994-12-31

169

Vapor compression distiller and membrane technology for water revitalization  

NASA Astrophysics Data System (ADS)

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

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

170

Vapor compression distiller and membrane technology for water revitalization.  

PubMed

Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied; one is an absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation able to easily produce condensed water under zero gravity was investigated experimentally and through simulated calculation. The vapor compression distiller was studied experimentally and it offers significant energy savings for evaporation of water. PMID:11537274

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

1987-01-01

171

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

NASA Astrophysics Data System (ADS)

A method for remote sensing of total precipitable water vapor using water vapor absorption band at 0.94 µm 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 applications over land regions. The method is applied for glint regions measured by the Moderate Resolution Imaging Spectro-radiometer (MODIS) simulator, an imager flown on the NASA ER-2 research aircraft and simulating the expected measurements from the MODIS instrument on board the Earth Observing System (EOS)-Terra satellite. The measurements are made for the Atlantic coast of the United States during the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX). The remote sensing technique is compared with measurements of water vapor column by the Lidar Atmospheric Sensing Experiment (LASE) Differential Infrared Absorption Lidar (DIAL) lidar system also on board the ER-2. Water vapor was derived with an error of ±5 mm PW (precipitable water vapor). Most of the errors are associated with the limitations of an experiment that was not originally designed for this purpose. Much better performance is expected from the actual MODIS instrument.

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

172

Improved algorithm for global map of water vapor contents  

NASA Astrophysics Data System (ADS)

Improved algorithm for global map of water vapor contents S.Mukai, I.Sano, M.Taniguchi(1) and Y.Okada(2) (1)Kinki University,(2)Kobe University An improved retrieval algorithm for water vapor content from satellite data is described. A POLDER sensor, mounted on the Earth observation satellite ADEOS in 1996, is a unique sensor, which can gather multi-directional (up to 14) polarization measurements of one target. The POLDER sensor is mounted on the satellite ADEOS-II launched on 14 December in 2002. Two channels in the near infrared wavelengths are used to estimate the total column water vapor content. The first channel is in the water vapor absorption band of 0.910 mm and the second is in the gas absorption-free band of 0.865 mm. In practice, a ratio of each reflectance for these two channels is used to estimate the total column water vapor content. This procedure has been proposed as a CNES/POLDER standard algorithm [Vesperini et al., 1999], and restricted to the clear-sky pixels over the land and sun-glitter pixels over the ocean. Further assumptions applied to this method are as follows; surface reflectivity is constant over the two channels, scattering by atmospheric aerosols is not significant at these channels, and the total column water vapor content is not significantly affected by the vertical profile of water vapor. This work intends to reduce the restrictions on the method mentioned above. It is shown first that the thermal data is available for retrieval of water vapor contents over the ocean given by ADEOS/OCTS or its successor, ADEOS-II/GLI. Thus the global map of water vapor contents all over the world involving the land and the whole ocean is obtained. Second spectral properties of the land surface are taken into account based on IGBP-DIS/DISCover data. It is found that an assumption of constant surface reflectivity over the two channels is not available, especially for grass-covered land. Furthermore atmospheric effect by aerosols is considered. The obtained satellite derived results are validated with the ground-based data as AERONET, ECMWF etc. Finally the obtained results of water vapor contents are compared with cloud microphysics and aerosol properties to understand the hydrologic cycles in the Earth-atmosphere surface system.

Mukai, S.; Sano, I.; Taniguchi, M.; Okada, Y.

173

Wavelength-modulation laser hygrometer for ultrasensitive detection of water vapor in semiconductor gases.  

PubMed

Water vapor is measured by use of a near-infrared diode laser and wavelength-modulation absorption spectroscopy. Humidity levels as low as 5 nmol/mol [1 nmol/mol = 1 ppb (1 ppb equals 1 part in 10(9))] of water vapor in air are measured with a sensitivity of better than 0.2 nmol/mol (3varsigma). The sensitivity, linearity, and stability of the technique are determined in experiments conducted at the National Institute of Standards and Technology, Gaithersburg, Maryland, by use of the low frost-point humidity generator over the range from 5 nmol/mol to 2.5 mumol/mol of water vapor in air. The pressure-broadening coefficients for water broadened by helium [0.0199(6) cm(-1) atm(-1) HWHM] and by hydrogen chloride [0.268(6) cm(-1) atm(-1) HWHM] are reported for the water line at 1392.5 nm. PMID:18357063

Hovde, D C; Hodges, J T; Scace, G E; Silver, J A

2001-02-20

174

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

SciTech Connect

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

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

1990-09-20

175

The applicability of a scanning Raman lidar for measurements of aerosols and water vapor  

NASA Astrophysics Data System (ADS)

Assessing atmospheric water vapor measurements to the level of accuracy required for improving atmospheric radiation parameterizations has been difficult to achieve. This thesis describes how a new sensor, the NASA/GSFC Scanning Raman Lidar (SRL), is used to improve assessments of water vapor measurements. Water vapor profiles measured at night by this lidar during two field experiments are compared with those measured by radiosondes, dew point hygrometers, a microwave radiometer, sun photometers, and the LASE lidar. During the first experiment, the SRL data show differences in water vapor mixing ratio and precipitable water vapor measurements as high as 10-15%; during the second, the SRL data reveal: (1) 10-15% differences in the Vaisala and VIZ radiosonde water vapor mixing ratio profiles below two kilometers, and (2) agreement within 5% between the SRL, dew point hygrometers, and LASE. These comparisons show that, by measuring water vapor to within about 5%, the SRL can be used to evaluate point, profile, and integrated water vapor measurements. Since this lidar detects Raman scattering from nitrogen and oxygen as well as the elastic scattering from molecules and aerosols, it measures both aerosol backscattering and extinction simultaneously with water vapor in the same scattering volume. Therefore, this instrument is well suited to study the interaction between water vapor and aerosols. Measurements of aerosol scattering from a tower-mounted nephelometer are found to be 40% lower than lidar measurements of aerosol extinction over a wide range of relative humidities even after accounting for the difference in wavelengths. The lidar profiles of aerosol backscattering and extinction compare well with those derived from aerosol size distribution measurements made by a PCASP (Passive Cavity Aerosol Spectrometer Probe) optical particle counter. Using both measurements, the change in particle size with relative humidity, the aerosol real refractive index n, and the single scattering albedo ?o are derived and are shown to vary with time and altitude. Values of n ranged between 1.4-1.5 (dry) and 1.37-1.47 (wet); ?o varied between 0.7-1.0. The SRL data show the ratio of aerosol extinction at 80% relative humidity to that at 60% relative humidity varies between 1.7 to 2.1.

Ferrare, Richard Anthony

1997-12-01

176

Enthalpy of Vaporization by Gas Chromatography: A Physical Chemistry Experiment  

ERIC Educational Resources Information Center

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

Ellison, Herbert R.

2005-01-01

177

Climatology and interannual variability of diurnal water vapor heating  

NASA Astrophysics Data System (ADS)

Tropospheric heating by water vapor absorption of near-infrared (IR) radiation is a leading drive of the propagating diurnal tide. A climatology of monthly diurnal water vapor IR heating rates is derived using National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and a global precipitable water (PW) data set. The new climatology updates an existing one compiled in 1982 that provides seasonally averaged IR heating between 35°S and 35°N. The new heating rates have greater temporal and spatial resolution and enable examination of intraseasonal and year-to-year variability over the 10-year span of the PW data set. Our findings suggest that tropical tropospheric variability may be communicated to the diurnal tide (and possibly the middle and upper atmosphere) by means of water vapor heating.

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

2003-02-01

178

Removal of Sarin Aerosol and Vapor by Water Sprays  

SciTech Connect

Falling water drops can collect particles and soluble or reactive vapor from the gas through which they fall. Rain is known to remove particles and vapors by the process of rainout. Water sprays can be used to remove radioactive aerosol from the atmosphere of a nuclear reactor containment building. There is a potential for water sprays to be used as a mitigation technique to remove chemical or bio- logical agents from the air. This paper is a quick-look at water spray removal. It is not definitive but rather provides a reasonable basic model for particle and gas removal and presents an example calcu- lation of sarin removal from a BART station. This work ~ a starting point and the results indicate that further modeling and exploration of additional mechanisms for particle and vapor removal may prove beneficial.

Brockmann, John E.

1998-09-01

179

Turbulent exchange of heat, water vapor, and momentum over a Tibetan prairie by eddy covariance and flux variance measurements  

Microsoft Academic Search

Land-atmosphere interactions on the Tibetan Plateau are important because of their influence on energy and water cycles on both regional and global scales. Flux variance and eddy covariance methods were used to measure turbulent fluxes of heat, water vapor, and momentum over a Tibetan shortgrass prairie during the Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) in

Taejin Choi; Jinkyu Hong; Joon Kim; Heechoon Lee; Jun Asanuma; Hirohiko Ishikawa; Osamu Tsukamoto; Gao Zhiqiu; Yaoming Ma; Kenichi Ueno; Jiemin Wang; Toshio Koike; Tetsuo Yasunari

2004-01-01

180

Water vapor electrolysis: systems considerations and cost\\/performance benefits  

Microsoft Academic Search

The energy intensiveness of conventional liquid water electrolysis has inhibited the universal acceptance of this established technology as a resource conversion, storage and transport option. New developments in recent years have focused on the goal of reducing electric energy requirements as well as overall system capital cost. Major gains are envisioned in meeting these goals if water vapor electrolysis were

F. J. Salzano; G. Skaperdas; A. Mezzina

1984-01-01

181

Aircraft Lidar Sensitivity Study for Measuring Water Vapor.  

National Technical Information Service (NTIS)

The amount of water in the optical path between an airborne measurement platform and a target is responsible for the difference between the actual and the measurement target spectral radiance. In situ measurements of water vapor can be limited by outgassi...

O. Shepherd R. J. Rieder

1991-01-01

182

Vapor compression distiller and membrane technology for water revitalization  

Microsoft Academic Search

Water revitalization for a space station can consist of membrane filtration processes and a distillation process. Water recycling equipment using membrane filtration processes was manufactured for ground testing. It was assembled using commercially available components. Two systems for the distillation are studied; one is an absorption type thermopervaporation cell and the other is a vapor compression distiller. Absorption type thermopervaporation

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

1987-01-01

183

Adsorption of radon and water vapor on commercial activated carbons  

SciTech Connect

Equilibrium adsorption isotherms are reported for radon and water vapor on two commercial activated carbons: coconut shell Type PCB and hardwood Type BD. The isotherms of the water vapor were measured gravimetrically at 298 K. The isotherms of radon from dry nitrogen were obtained at 293, 298, and 308 K while the data for the mixture of radon and water vapor were measured at 298 K. The concentrations of radon in the gas and solid phases were measured simultaneously, once the adsorption equilibrium and the radioactive equilibrium between the radon and its daughter products were established. The shape of the isotherms was of Type III for the radon and Type V for the water vapor, according to Brunauer`s classification. The adsorption mechanism was similar for both the radon and the water vapor, being physical adsorption on the macropore surface area in the low pressure region and micropore filling near saturation pressure. The uptake capacity of radon decreased both with increasing temperature and relative humidity. The heat of adsorption data indicated that the PCB- and the BD-activated carbons provided a heterogeneous surface for radon adsorption. The equilibrium data for radon were correlated with a modified Freundlich equation.

Hassan, N.M. [Westinghouse Savannah River Co., Aiken, SC (United States); Ghosh, T.K.; Hines, A.L.; Loyalka, S.K. [Univ. of Missouri, Columbia, MO (United States)

1995-02-01

184

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

SciTech Connect

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.

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

1995-06-01

185

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

Microsoft Academic Search

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

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

1990-01-01

186

A steady-state analysis of the temperature responses of water vapor and aerosol lifetimes  

NASA Astrophysics Data System (ADS)

The dominant removal mechanism of soluble aerosol is wet deposition. The atmospheric lifetime of aerosol, relevant for aerosol radiative forcing, is therefore coupled to the atmospheric cycling time of water vapor. This study investigates the coupling between water vapor and aerosol lifetimes in a well-mixed atmosphere. Based on a steady-state study by Pruppacher and Jaenicke (1995) we describe the coupling in terms of the processing efficiency of air by clouds and the efficiencies of water vapor condensation, of aerosol activation, and of the transfer from cloud water to precipitation. We extend this to expressions for the temperature responses of the water vapor and aerosol lifetimes. Previous climate model results (Held and Soden, 2006) suggest a water vapor lifetime temperature response of +5.3 ± 2.0% K-1. This can be used as a first guess for the aerosol lifetime temperature response, but temperature sensitivities of the aerosol lifetime simulated in recent aerosol-climate model studies extend beyond this range and include negative values. This indicates that other influences probably have a larger impact on the computed aerosol lifetime than its temperature response, more specifically changes in the spatial distributions of aerosol (precursor) emissions and precipitation patterns, and changes in the activation efficiency of aerosol. These are not quantitatively evaluated in this study but we present suggestions for model experiments that may help to understand and quantify the different factors that determine the aerosol atmospheric lifetime.

Roelofs, G.-J.

2013-08-01

187

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

NASA Astrophysics Data System (ADS)

Stratospheric water vapor plays an important role in the Earth system, both through its role in stratospheric ozone destruction and as a greenhouse gas contributing to radiative forcing of the climate. Highly accurate water vapor measurements are critical to understanding how stratospheric water vapor concentrations will respond to a changing climate. However, the past disagreement among water vapor instruments on the order of 1-2 ppmv hinders understanding of the mechanisms which control stratospheric humidity, and the reliable detection of water vapor trends. In response to these issues, we present a new dual axis water vapor instrument that combines the heritage Harvard Lyman-alpha hygrometer with the newly developed Harvard Herriott Hygrometer (HHH). The Lyman-alpha instrument utilizes ultraviolet photo-fragment fluorescence detection, and its accuracy has been demonstrated though rigorous laboratory calibrations and in situ diagnostic procedures. HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell; it demonstrated in-flight precision of 0.1 ppmv (1-sec) with accuracy of 5%±0.5 ppmv. We describe these two measurement techniques in detail along with our methodology for calibration and details of the measurement uncertainties. We also examine the recent flight comparison of the two instruments with several other in situ hygrometers during the 2011 MACPEX campaign, in which five independent instruments agreed to within 0.7 ppmv, a significant improvement over past comparisons. Water vapor measurements in combination with simultaneous in situ measurements of O3, CO, CO2, HDO, and HCl are also used to investigate transport in the Tropical Tropopause Layer (TTL). Data from the winter 2006 CR-AVE campaign and the summer 2007 TC4 campaign are analyzed in a one-dimensional mixing model to explore the seasonal importance of transport within the TTL via slow upward ascent, convective injection, and isentropic transport from the midlatitude stratosphere. The model shows transport from midlatitudes to be significant in summer and winter, affecting ozone concentrations and therefore the radiative balance of the TTL. It also shows significant convective influence up to 420 K potential temperature in both seasons, which appreciably increases the amount of water vapor above the tropopause.

Sargent, Maryann Racine

188

Combining Suborbital Measurements of Aerosol Optical Depth and Columnar Water Vapor for Satellite Sensor Validations in the CLAMS (Chesapeake Lighthouse and Aircraft Measurements for Satellites) Experiment, 2001  

Microsoft Academic Search

As part of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment, July 10 - August 2, 2001, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated successfully aboard the University of Washington Convair-580 during 10 research flights (~45 flight hours). The CLAMS campaign was a clear sky, shortwave (SW) closure campaign that entailed measurements from the Chesapeake

J. Redemann; B. Schmid; J. M. Livingston; P. B. Russell; J. A. Eilers; P. V. Hobbs; R. Kahn; W. L. Smith; B. N. Holben; C. K. Rutledge; M. C. Pitts; M. I. Mishchenko; J. Chowdhary; J. V. Martins; A. Plana-Fattori; T. P. Charlock

2002-01-01

189

Optimized strategy analysis on retrieval of GPS precipitable water vapor  

NASA Astrophysics Data System (ADS)

This paper mainly discusses how to determine the optimized strategy for retrieval of Precipitable Water Vapor (PWV) with high accuracy from tropospheric zenith wet delay using ground-based GPS receivers. GPS analytical network are constructed on the base of two observation sites in Antarctica in 1999 and several IGS sites. Tests are conducted to study the performance of different network sizes and different schemes parameters. A high-accuracy GPS processing software package GAMIT/GLOBK is utilized; multiple schemes are adopted for searching the optimized parameters for accurate PWV. After having running GAMIT/GLOBK of all test combination, the results are analyzed by Baseline Repeatability Rate(BRR) and bias between calculated GPS water vapor and actual water vapor. The primary achievements and conclusion are reached including the optimal IGS sites involved, network configurations, elevation cut-off angles, processing periods, knots position.

Gu, Xiaoping; Cong, Pifu; Wang, Changyao; Chen, Xiao; Wang, Wen; Yuan, Shujie

2005-11-01

190

Global upper tropospheric/lower stratospheric water vapor from satellites  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

191

Validation of the SCIAMACHY limb water vapor retrieval  

NASA Astrophysics Data System (ADS)

The upper troposphere and lower stratosphere (UTLS) is a region of special interest for a variety of dynamical and chemical processes. Water vapor in the UTLS plays an important role for the radiative budget of the atmosphere, therefore consistent long term measurements are important. Measurements of scattered sunlight from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY) in the limb viewing geometry allow to retrieve water vapor in the UTLS, at about 12 to 23 km altitude. Onboard Envisat, SCIAMACHY measurements are available for nearly one decade, between August 2002 and April 2012. Here, we present a validation of the latest data version of water vapor from SCIAMACHY measurements by comparsisons with occultation data from SCIAMACHY, other satellite data and frost point hygrometer data. The time series from 2002 to 2012 is presented and their variability during the last decade is investigated

Weigel, Katja; Rozanov, Alexei; Azam, Faiza; Bramstedt, Klaus; Eichmann, Kai-Uwe; Weber, Mark; Bovensmann, Heinrich; Burrows, John P.

2013-04-01

192

Evolution of melt-vapor surface tension in silicic volcanic systems: Experiments with hydrous melts  

USGS Publications Warehouse

We evaluate the melt-vapor surface tension (??) of natural, water-saturated dacite melt at 200 MPa, 950-1055??C, and 4.8-5.7 wt % H2O. We experimentally determine the critical supersaturation pressure for bubble nucleation as a function of dissolved water and then solve for ?? at those conditions using classical nucleation theory. The solutions obtained give dacite melt-vapor surface tensions that vary inversely with dissolved water from 0.042 (??0.003) J m-2 at 5.7 wt% H2O to 0.060 (??0.007) J m-2 at 5.2 wt% H2O to 0.073 (??0.003) J m-2 at 4.8 wt% H2O. Combining our dacite results with data from published hydrous haplogranite and high-silica rhyolite experiments reveals that melt-vapor surface tension also varies inversely with the concentration of mafic melt components (e.g., CaO, FeOtotal, MgO). We develop a thermodynamic context for these observations in which melt-vapor surface tension is represented by a balance of work terms controlled by melt structure. Overall, our results suggest that cooling, crystallization, and vapor exsolution cause systematic changes in ?? that should be considered in dynamic modeling of magmatic processes.

Mangan, M.; Sisson, T.

2005-01-01

193

Water vapor and gas transport through a poly(butylene terephthalate) poly(ethylene oxide) block copolymer  

Microsoft Academic Search

In this paper the transport behavior of water vapor and nitrogen in a poly(butylene terephthalate) poly (ethylene oxide) block copolymer is discussed. This polymer has a high solubility for water (300 cm3 (STP)\\/cm3 polymer at activity 0.9). A new permeation set up has been built to determine the water vapor and nitrogen transport rates from mixed gas experiments at temperatures

S. J. Metz; J. Potreck; M. H. V. Mulder; M. Wessling

2002-01-01

194

Modeling upper tropospheric and lower stratospheric water vapor anomalies  

NASA Astrophysics Data System (ADS)

The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler (2011) is used to further investigate processes that produce upper tropospheric and lower stratospheric water vapor anomalies. We examine the pathways parcels take from the base of the tropical tropopause layer (TTL) to the lower stratosphere. Most parcels found in the lower stratosphere arise from East Asia, the Tropical West Pacific (TWP) and the Central/South America. The belt of TTL parcel origins is very wide compared to the final dehydration zones near the top of the TTL. This is due to the convergence of rising air as a result of the stronger diabatic heating near the tropopause relative to levels above and below. The observed water vapor anomalies - both wet and dry - correspond to regions where parcels have minimal displacement from their initialization. These minimum displacement regions include the winter TWP and the Asian and American monsoons. To better understand the stratospheric water vapor concentration we introduce the water vapor spectrum and investigate the source of the wettest and driest components of the spectrum. We find that the driest air parcels that originate below the TWP, moving upward to dehydrate in the TWP cold upper troposphere. The wettest air parcels originate at the edges of the TWP as well as the summer American and Asian monsoons. The wet air parcels are important since they skew the mean stratospheric water vapor distribution toward higher values. Both TWP cold temperatures that produce dry parcels as well as extra-TWP processes that control the wet parcels determine stratospheric water vapor.

Schoeberl, M. R.; Dessler, A. E.; Wang, T.

2013-04-01

195

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

NASA Astrophysics Data System (ADS)

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.

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

2008-12-01

196

Analysis of the CO 2 capture in sodium zirconate (Na 2ZrO 3). Effect of the water vapor addition  

Microsoft Academic Search

Sodium metazirconate (Na2ZrO3) was synthesized, by solid-state reaction, and characterized. Water sorption experiments were performed using N2 and CO2 as carrier gases. In the absence of CO2, Na2ZrO3 showed considerably high water vapor sorption owing to two different processes, hydroxylation and water vapor adsorption. When CO2 was used as the water vapor carrier gas, the reactivity of Na2ZrO3 was found

Gloria G. Santillán-Reyes; Heriberto Pfeiffer

197

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

SciTech Connect

An increasing research interest in the determination of the salt effect in the vapor-liquid equilibrium of binary systems has developed over the last few decades due to the importance of distillation with salts in the separation of close boiling and azeotropic mixtures. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + potassium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.642 has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.

Vercher, E.; Pena, M.P.; Martinez-Andreu, A. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1996-01-01

198

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

SciTech Connect

The effect of salts on the vapor-liquid equilibrium of solvent mixtures is of considerable interest in the separation of close boiling and azeotropic mixtures. The salt effect has been studied by many researchers. Most investigations have been limited to measurements on the saturated salt solutions. Isobaric vapor-liquid equilibrium for ethanol (1) + water (2) + strontium nitrate (3) at various concentrations of salt and with ethanol mole fractions from 0 to 0.672, has been measured at 100.0 kPa. The results were correlated by assuming that the salt was in ionic form and it was associated only with the water.

Vercher, E.; Pena, M.P.; Martinez-Andreu, A. [Univ. de Valencia (Spain)

1996-07-01

199

Water vapor from new Microwave Limb Sounder on Aura (WMS)  

NSDL National Science Digital Library

Water vapor (H2O) in the atmosphere as measured by the Microwave Limb Sounder (MLS) instrument on NASAs Aura satellite. MLS can simultaneously measure several trace gases and ozone-destroying chemicals in the upper troposphere and photosphere. In this series of animiations we present chlorine monoxide (ClO), hydrogen chloride (HCl), nitric acid (HNO3), ozone (O3), water vapor (H2O) and temperature measurements. These are first light data taken when the MLS was operated for the first time.

Perkins, Lori; Delabeaujardiere, Jeff; Schoeberl, Mark

2005-01-27

200

Calibrated In Situ Measurement of UT/LS Water Vapor Using Chemical Ionization Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Over the past several decades there has been considerable disagreement among in situ water vapor measurements by different instruments at the low part per million (ppm) mixing ratios found in the upper troposphere and lower stratosphere (UT/LS). These discrepancies contribute to uncertainty in our understanding of the microphysics related to cirrus cloud particle nucleation and growth and affect our ability to determine the effect of climate changes on the radiatively important feedback from UT/LS water vapor. To address the discrepancies observed in measured UT/LS water vapor, a new chemical ionization mass spectrometer (CIMS) instrument has been developed for the fast, precise, and accurate measurement of water vapor at low mixing ratios. The instrument utilizes a radioactive ? particle source to ionize a flow of sample air drawn into the instrument. A cascade of ion-molecule reactions results in the production of protonated water ions proportional to the water vapor mixing ratio that are then detected by the mass spectrometer. The multi-step nature of the ionization mechanism results in a non-linear sensitivity to water vapor, necessitating calibration across the full range of values to be measured. To accomplish this calibration, we have developed a novel calibration scheme using catalytic oxidation of hydrogen to produce well-defined water vapor mixing ratios that can be introduced into the instrument inlet during flight. The CIMS instrument was deployed for the first time aboard the NASA WB-57 high altitude research aircraft during the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) mission in March and April 2011. The sensitivity of the instrument to water vapor was calibrated every ~45 minutes in flight from < 1 to 150 ppm. Analysis of in-flight data demonstrates a typical sensitivity of 2000 Hz/ppm at 4.5 ppm with a signal to noise ratio (2 ?) > 50 for a 1 second measurement. The instrument and its calibration system performed successfully in 7 flights during the MACPEX mission, sampling water vapor mixing ratios as low as 4 ppm in stratospheric air. A comparison of the new measurement with other measurements on board the aircraft is expected to help resolve the long-standing differences in low water measurements in the lower stratosphere.

Thornberry, T. D.; Rollins, A.; Gao, R.; Watts, L. A.; Ciciora, S. J.; McLaughlin, R. J.; Fahey, D. W.

2011-12-01

201

Clear-sky column water vapor retrievals using the Airborne Imaging Microwave Radiometer (AIMR)  

Microsoft Academic Search

The brightness temperature measurements from the Airborne Imaging Microwave Radiometer (AIMR) microwave radiometer 37 GHz and 90 GHz channels are used to determine the column water vapor amount under clear-sky conditions during the Indian Ocean Experiment (INDOEX) campaign in 1999. The retrieval algorithm is based on the integrated relative humidity profiles measured by numerous dropsondes released from the National Center

Brett C. Bush; Francisco P. J. Valero; Julie A. Haggerty

2007-01-01

202

Observed Seasonal to Decadal-Scale Responses in Mesospheric Water Vapor.  

National Technical Information Service (NTIS)

The 14-yr (1991-2005) time series of mesospheric water vapor from the Halogen Occultation Experiment (HALOE) are analyzed using multiple linear regression (MLR) techniques for their6 seasonal and longer-period terms from 45S to 45N. The distribution of an...

E. Remsberg

2010-01-01

203

A high stability ka-band radiometer for tropospheric water vapor measurements  

Microsoft Academic Search

The design of two new high stability microwave water vapor radiometers is presented along with a performance evaluation. The radiometers operate next to a spacecraft tracking station at NASA's Goldstone facility in California where they will be used to calibrate tropospheric path delay fluctuations during an upcoming gravity wave search experiment (GWE) involving the Cassini spacecraft. Observing frequencies of the

Alan B. Tanner

2001-01-01

204

Spectroscopy of water vapor in the 930 nm to 960 nm spectral region  

Microsoft Academic Search

A new laser is being developed for the LASE (Lidar Atmospheric Sensing Experiment) system around 946 nm. We have modified a system that characterizes water vapor in the 930-960 nm region of the spectrum for pressure shifts, broadening coefficients and cross-sections. The relative wavelength scale for each scan is determined with a Fabry Perot etalon and White cells with an

C. K. Williamson; S. Ismail; E. V. Browell

1999-01-01

205

Effect of water vapor on the distribution of the parameters of a turbulent wake  

SciTech Connect

In the experimental study of phenomena occurring in the flow of air round models flying along a aeroballistic range with hypersonic velocities, the question arises of the effect of water vapor along the range on the measurements of the gas parameters, for example, on the electron concentration or on the intensity of the radiation. Water vapor is usually present in atmospheric air and, in the absence of special measures to remove it, it may have an influence on the results of measurements. In an earlier paper, a theoretical study was made of the effect of chemical reactions involving the participation of water vapor in the air on the chemiluminescent radiation in the wake alone. In particular, there was no consideration of the effect of water vapor on the electron concentration. In the present study, the results are given of calculations of the distributions of the nonequilibrium parameters in the wake, with allowance for the occurrence of chemical reactions in the air and water vapor under conditions characteristic of aeroballistic experiments.

Pilyugin, N.N.; Tikhomirov, S.G.

1985-07-01

206

Validating AIRS upper atmosphere water vapor retrievals using aircraft and balloon in situ measurements  

NASA Astrophysics Data System (ADS)

This paper provides an initial assessment of the accuracy of the Atmospheric Infrared Sounder (AIRS) water vapor retrievals from 500 to 100 mbar. AIRS satellite measurements are compared with accurate aircraft (NASA WB57) and balloon in situ water vapor measurements obtained during the NASA Pre-Aura Validation Experiment (Pre-AVE) in Costa Rica during Jan. 2004. AIRS retrieval (each pressure level of a single footprint) of water vapor amount agrees with the in situ measurements to ~25% or better if matched closely in time (1 hr) and space (50-100 km). Both AIRS and in situ measurements observe similar significant variation in moisture amount over a two-day period, associated with large-scale changes in weather patterns.

Hagan, D. E.; Webster, C. R.; Farmer, C. B.; May, R. D.; Herman, R. L.; Weinstock, E. M.; Christensen, L. E.; Lait, L. R.; Newman, P. A.

2004-11-01

207

Water Vapor Enhancement in the Polar Summer Mesosphere and its Relationship to Polar Mesospheric Clouds  

NASA Astrophysics Data System (ADS)

Polar mesospheric water vapor exhibits a strong seasonal cycle, with summer mixing ratios dramatically higher than in winter. It is generally accepted that vertical transport from ~50 km altitude towards the mesopause is one driver behind this change, however, upwelling alone cannot explain observed H2O changes. H2O near 83 km increases from 1 ppmv in winter to over 8 ppmv in summer, and upwelling accounts for roughly half of this increase. It has been suggested that evaporation of polar mesospheric clouds (PMCs) should produce a layer of enhanced water vapor. This idea was challenged using particle measurements from the Halogen Occultation Experiment (HALOE) to derive the equivalent gas phase H2O contained in PMCs. Comparing these estimates to HALOE water vapor measurements suggests that PMC evaporation is a large component in H2O enhancement near 83 km during summer.

Hervig, M.; McHugh, M.; Summers, M.

2003-12-01

208

Water vapor enhancement in the polar summer mesosphere and its relationship to polar mesospheric clouds  

NASA Astrophysics Data System (ADS)

Polar mesospheric water vapor exhibits a strong seasonal cycle, with summer mixing ratios dramatically higher than in winter. It is generally accepted that vertical transport from ~50 km altitude towards the mesopause is one driver behind this change, however, upwelling alone cannot explain observed H2O changes. H2O near 83 km increases from 1 ppmv in winter to over 8 ppmv in summer, and upwelling accounts for roughly half of this increase. It has been suggested that evaporation of polar mesospheric clouds (PMCs) should produce a layer of enhanced water vapor. This idea was explored using particle measurements from the Halogen Occultation Experiment (HALOE) to derive the equivalent gas phase H2O contained in PMCs. Comparing these estimates to HALOE water vapor measurements suggests that PMC evaporation is a large component in H2O enhancement near 83 km during summer.

Hervig, Mark; McHugh, Marty; Summers, Michael E.

2003-10-01

209

A water vapor monitor using differential infrared absorption  

NASA Astrophysics Data System (ADS)

A water vapor monitor was developed with adequate sensitivity and versatility for a variety of applications. Two applications are the continuous monitoring of water in ambient air and the measuring of the mass of water desorbed from aerosol filters. The sample gas may be held static, or flow continuously through the 56 cc sample cell, temperature controlled at 45 C. Infrared energy from a tungsten-iodide bulb passes through a rotating filter wheel and the sample cell to a PbS detector. The infrared beam passes through the sample gas twice to produce a total optical path of 40 cm. The infrared beam passes alternately through two semicircular narrow bandpass filters. Absorption by the water vapor in the sample produces a 30-Hz modulation of the detector signal that is proportional to the water concentration. The maximum concentration that can be measured accurately is approximately 5%.

Burch, D. E.; Goodsell, D. S.

1981-09-01

210

Investigating Vaporization of Silica through Laser Driven Shock Wave Experiments  

NASA Astrophysics Data System (ADS)

Giant impacts melt and vaporize a significant amount of the bolide and target body. However, our ability to determine how much melt or vapor a given impact creates depends strongly on our understanding of the liquid-vapor phase boundary of geologic materials. Our current knowledge of the liquid-vapor equilibrium for one of the most important minerals, SiO2, is rather limited due to the difficulty of performing experiments in this area of phase space. In this study, we investigate the liquid-vapor coexistence region by shocking quartz into a supercritical fluid state and allowing it to adiabatically expand to a state on the liquid-vapor phase boundary. Although shock compression and release has been used to study the liquid-vapor equilibrium of metals [1], few attempts have been made at studying geologic materials by this method [2]. Shock waves were produced by direct ablation of the quartz sample using the Jupiter Laser Facility of Lawrence Livermore National Laboratory. Steady shock pressures of 120-360 GPa were produced in the quartz samples: high enough to force the quartz into a supercritical fluid state. As the shock wave propagates through the sample, we measure the shock velocity using a line imaging velocity interferometer system for any reflector (VISAR) and shock temperature using a streaked optical pyrometer (SOP). When the shock wave reaches the free surface of the sample, the material adiabatically expands. Upon breakout of the shock at the free surface, the SOP records a distinct drop in radiance due to the lower temperature of the expanded material. For a subset of experiments, a LiF window is positioned downrange of the expanding silica. When the expanding silica impacts the LiF window, the velocity at the interface between the expanding silica and LiF window is measured using the VISAR. From the shock velocity measurements, we accurately determine the shocked state in the quartz. The post-shock radiance measurements are used to constrain the temperature on the liquid-vapor phase boundary (e.g., [3]) at much higher pressures than previously possible using a 2 stage gas gun [4, 5]. The density on the liquid-vapor phase boundary is constrained by comparing the velocity at the silica-LiF interface to numerical simulations that use equations of state with systematically varied liquid-vapor phase boundaries. We present the results within the context of understanding vaporization during giant impact events. [1] Brannon, R.M. and L.C. Chhabildas (1995) Int. J. Impact Engng. 17, 109-120. [2] Kurosawa, K. and S. Sugita (2010) J. Geophys. Res. in press. [3] Stewart, S.T., A. Seifter, and A.W. Obst (2008) Geophys. Res. Lett., 35, (23). [4] Lyzenga, G.A., T.J. Ahrens, and A.C. Mitchell (1983) J. Geophys. Res. , 88, (NB3), 2431-2444. [5] Boslough, M.B. (1988) J. Geophys. Res., 93, (B6), 6477-6484.

Kraus, R. G.; Swift, D. C.; Stewart, S. T.; Smith, R.; Bolme, C. A.; Spaulding, D. K.; Hicks, D.; Eggert, J.; Collins, G.

2010-12-01

211

Molecular Mechanisms of Conduction and Polarization in Water Vapor, Liquid Water, and Ice.  

National Technical Information Service (NTIS)

After a short review of the pertinent prehistory, the investigation starts with water vapor. Thermal ionization requires formation of special association complexes and their dissociation by infrared vibrations. The corresponding process occurs in water an...

A. R. von Hippel

1973-01-01

212

Evaluation of the coadsorption effect of water vapor and organic vapors on charcoal sampling tubes  

SciTech Connect

The purpose of this study was to investigate some of the factors influencing the potential interference caused by water vapor when collecting organic vapors on 100 mg charcoal tubes. Atmospheres containing known concentrations of organic vapors at predetermined relative humidities were produced in a flow dilution system. Atmospheres of the solvents toluene, methyl chloroform, methyl isobutyl ketone (MIBK), cyclohexane, acetone, isopropanol, acetonitrile, ethyl acetate, 1-butanol, and perchloroethylene, were screened at 0 and 90% relative humidity to select solvents which exhibited varying degrees of effect of humidity for more detailed study. The solvents toluene, methyl chloroform, MIBK and cyclohexane were studied at concentrations ranging from 50 to 1400 ppm or 1/4 to 8 times the OSHA 8-hour Permissible Exposure Limit (PEL) concentration which enabled comparison of the different solvents at similar molar concentrations. Water vapor levels of approximately 0, 50, 70, 80, and 90% relative humidity at 25/sup 0/C were tested for each concentration of each solvent. The recoveries obtained for the recommended air volume samples taken at all combinations of solvent concentration and humidity ranged from 0.54 to 1.54.

Wells, W.H. Jr.

1986-01-01

213

Modeling the behavior of tritiated water vapor in a research reactor containment building.  

PubMed

Mathematical models were developed to predict the changes in tritiated water (HTO) concentrations in water pools and of HTO vapor in the Kyoto University Reactor (KUR) containment building in which approximately 3.4 x 10(2) GBq of HTO vapor had leaked from a heavy water facility for more than 1 y. Models reveal that the mechanism of HTO vapor transfer between air and water is controlled by two key parameters: the kinetic constant for HTO exchange and the evaporation rate constant from water to air. A model was constructed based on laboratory experiments using small glass dishes containing various volumes of HTO and was validated by comparing estimates to actual measurements for HTO concentration in water pools of various depths in the containment building. After the leakage from the heavy water facility had been stopped, the decrease in HTO concentration in the sub-pool could be described by this model with a half-life of 15 wk. A mathematical model was also developed to estimate the average HTO vapor concentration in air, which is strongly dependent on the ventilation system's operation even after the removal of the HTO sources. This is due to the continued release of HTO from the concrete material and is analogous to the dynamics of radon emanation. The amount of HTO that has emerged from the concrete was estimated using a model developed for HTO concentration changes in the containment building air, based on long-term monitoring. PMID:1730556

Fukui, M

1992-02-01

214

Convenient thermal\\/vapor barrier for constant temperature water bath  

Microsoft Academic Search

We report a simple scheme to install an effective thermal\\/vapor barrier for precision temperature baths. We have found that by floating on the water surface, a pile of common packing material such as styrofoam pellets fused together by a solvent spray, a ten-fold reduction in the bath temperature fluctuation can be achieved.

John S. Huang; Mahn Won Kim

1980-01-01

215

Convenient thermal/vapor barrier for constant temperature water bath  

NASA Astrophysics Data System (ADS)

We report a simple scheme to install an effective thermal/vapor barrier for precision temperature baths. We have found that by floating on the water surface, a pile of common packing material such as styrofoam pellets fused together by a solvent spray, a ten-fold reduction in the bath temperature fluctuation can be achieved.

Huang, John S.; Kim, Mahn Won

1980-06-01

216

Oxidation of Ultra High Temperature Ceramics in Water Vapor.  

National Technical Information Service (NTIS)

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 ...

Q. G. N. Nguyen E. J. Opila R. C. Robinson

2004-01-01

217

Optimized strategy analysis on retrieval of GPS precipitable water vapor  

Microsoft Academic Search

This paper mainly discusses how to determine the optimized strategy for retrieval of Precipitable Water Vapor (PWV) with high accuracy from tropospheric zenith wet delay using ground-based GPS receivers. GPS analytical network are constructed on the base of two observation sites in Antarctica in 1999 and several IGS sites. Tests are conducted to study the performance of different network sizes

Xiaoping Gu; Pifu Cong; Changyao Wang; Xiao Chen; Wen Wang; Shujie Yuan

2005-01-01

218

Thirty Meter Telescope Site Testing X: Precipitable Water Vapor  

Microsoft Academic Search

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

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

2010-01-01

219

Computer simulation of the NASA water vapor electrolysis reactor  

Microsoft Academic Search

A digital computer simulation of the water vapor electrolysis reactor, an oxygen regenerator to be used in extended-mission manned spacecraft, was developed as a design tool and as a means for predicting response to unusual operating conditions. Finite increment analysis was applied to the mass, heat, and momentum transfer processes of the unit, yielding systems of non-linear algebraic equations defining

Allan M. Bloom

1974-01-01

220

Variations in water vapor continuum radiative transfer with atmospheric conditions  

NASA Astrophysics Data System (ADS)

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

Paynter, D.; Ramaswamy, V.

2012-08-01

221

Absorption of Solar Radiation by Water Vapor in the Atmosphere  

Microsoft Academic Search

Absorption of solar radiation by water vapor in the atmosphere has been studied, with use of Fowle's observed results and application of Elsasser's transmission function. The results are compared with those of other workers. Mügge-Möller's absorption curve and Karandikar's are discussed. As a result of calculations, an absorption chart is obtained from which both the absorption of solar radiation by

Giichi Yamamoto; Gaishi Onishi

1952-01-01

222

Lidar Monitoring of the Water Vapor Cycle in the Troposphere  

Microsoft Academic Search

The water vapor mixing ratio distribution in the lower and middle troposphere has been continuously monitored, using an active lidar system. The methodology of the differential absorption laser method used for these measurements is summarized and related to the corresponding achievements of the experimental system set up at the Haute-Provence Observatory, France. The experimental results emphasize the unique aspect of

C. Cahen; G. Megie; P. Flamant

1982-01-01

223

SCIAMACHY lunar occultation water vapor measurements: retrieval and validation results  

NASA Astrophysics Data System (ADS)

SCIAMACHY lunar occultation measurements have been used to derive vertical profiles of stratospheric water vapor for the Southern Hemisphere in the near infrared (NIR) spectral range of 1350-1420 nm. The focus of this study is to present the retrieval methodology including the sensitivity studies and optimizations for the implementation of the radiative transfer model on SCIAMACHY lunar occultation measurements. The study also includes the validation of the data product with the collocated measurements from two satellite occultation instruments and two instruments measuring in limb geometry. The SCIAMACHY lunar occultation water vapor measurements comparisons with the ACE-FTS instrument have shown an agreement of 5% on the average that is well within the reported biases of ACE in the stratosphere. The comparisons with HALOE have also shown good results where the agreement between the instruments is within 5%. The validations of the lunar occultation water vapor measurements with MLS instrument are exceptionally good varying between 1.5 to around 4%. The validations with MIPAS are in the range of 10%. A validated dataset of water vapor vertical distributions from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of physical and chemical processes in the southern mid-latitudes and the dynamical processes related to polar vortex.

Azam, F.; Bramstedt, K.; Rozanov, A.; Weigel, K.; Bovensmann, H.; Stiller, G. P.; Burrows, J. P.

2012-02-01

224

Characterization and error analyses of SAGE III water vapor retrieval  

Microsoft Academic Search

This paper presents an overview of the SAGE III water vapor retrieval algorithm. Results of simulated retrieval are shown to demonstrate the advantages of the non-linear optimization algorithm in reducing the influence of the contributions due to interfering species. Diagnostic analyses of the retrieval are conducted to examine the characteristics of the matrices of contribution functions and the averaging kernels.

Er-Woon Chiou; William P. Chu; Larry W. Thomason

2002-01-01

225

Effect of water vapor diffusion enhancement on soil moisture\\/temperature and evaporation - A numerical study  

Microsoft Academic Search

Experimental and numerical studies concerning the coupled flow of liquid water and water vapor in porous media have shown differences in observed and Fickian diffusion-based modeled water vapor fluxes. Early studies explain these differences with evaporation-condensation effects in liquid islands in the variably saturated zone and enhanced water vapor flux due to local thermal gradients which differ between the different

Christian Steenpass; Jan Vanderborght; Johan Alexander Huisman

2010-01-01

226

A SEARCH FOR WATER VAPORIZATION ON CERES  

SciTech Connect

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.

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

227

Interaction of water vapor with polycrystalline UO_2  

Microsoft Academic Search

We have studied the adsorption and desorption of water vapor (D_2O) on polycrystalline stoichiometric UO2 and oxygen-deficient UO2 surfaces, over the temperature range 100 K to 600 K, using XPS (X-ray photoelectron spectroscopy) and TPD (temperature programmed desorption) under UHV conditions. On the stoichiometric defect-free UO2 surface, water adsorbs and desorbs in molecular form. Sputtering with 1.5 keV Ar ions

B. V. Yakshinskiy; T. Schlereth; T. E. Madey

2004-01-01

228

Columnar water vapor retrievals from multifilter rotating shadowband radiometer data  

SciTech Connect

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

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

2009-01-26

229

Martian water vapor: Mars Express PFS/LW observations  

NASA Astrophysics Data System (ADS)

We present the seasonal and geographical variations of the martian water vapor monitored from the Planetary Fourier Spectrometer Long Wavelength Channel aboard the Mars Express spacecraft. Our dataset covers one martian year (end of Mars Year 26, Mars Year 27), but the seasonal coverage is far from complete. The seasonal and latitudinal behavior of the water vapor is globally consistent with previous datasets, Viking Orbiter Mars Atmospheric Water Detectors (MAWD) and Mars Global Surveyor Thermal Emission Spectrometer (MGS/TES), and with simultaneous results obtained from other Mars Express instruments, OMEGA and SPICAM. However, our absolute water columns are lower and higher by a factor of 1.5 than the values obtained by TES and SPICAM, respectively. In particular, we retrieve a Northern midsummer maximum of 60 pr-?m, lower than the 100-pr-?m observed by TES. The geographical distribution of water exhibits two local maxima at low latitudes, located over Tharsis and Arabia. Global Climate Model (GCM) simulations suggest that these local enhancements are controlled by atmospheric dynamics. During Northern spring, we observe a bulge of water vapor over the seasonal polar cap edge, consistent with the northward transport of water from the retreating seasonal cap to the permanent polar cap. In terms of vertical distribution, we find that the water volume mixing ratio over the large volcanos remains constant with the surface altitude within a factor of two. However, on the whole dataset we find that the water column, normalized to a fixed pressure, is anti-correlated with the surface pressure, indicating a vertical distribution intermediate between control by atmospheric saturation and confinement to a surface layer. This anti-correlation is not reproduced by GCM simulations of the water cycle, which do not include exchange between atmospheric and subsurface water. This situation suggests a possible role for regolith-atmosphere exchange in the martian water cycle.

Fouchet, T.; Lellouch, E.; Ignatiev, N. I.; Forget, F.; Titov, D. V.; Tschimmel, M.; Montmessin, F.; Formisano, V.; Giuranna, M.; Maturilli, A.; Encrenaz, T.

2007-09-01

230

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

Microsoft Academic Search

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

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

2008-01-01

231

Radiometric estimation of water vapor content over Brazil  

NASA Astrophysics Data System (ADS)

A multi-channel microwave radiometre (make: Radiometrics Corporation) is installed at Instituto Nacional de Pesquisas Espaciais-INPE, Brazil (22°S). The radiometric output of two channels of the radiometer in the form of brightness temperature at 23.834 GHz and 30 GHz, initially, were used to find out the ambient water vapor content and the non-precipitable cloud liquid water content. The necessary algorithm was developed for the purpose. The best results were obtained using the hinge frequency 23.834 GHz and 30 GHz pair having an r.m.s. error of only 2.64. The same methodology was then adopted exploiting 23.034 GHz and 30 GHz pair. In that case the r.m.s. error was 3.42. These results were then compared with those obtained over Kolkata (22°N), India, by using 22.234 GHz and 31.4 GHz radiometric data. This work conclusively suggests the use of a frequency should not be at the water vapor resonance line. Instead, while measuring the vapor content for separation of vapor and cloud liquid, one of them should be a few GHz left or right from the resonance line i.e., at 23.834 GHz and the other one should be around 30 GHz.

Karmakar, P. K.; Maiti, M.; Sett, S.; Angelis, C. F.; Machado, L. A. T.

2011-11-01

232

Three-dimensional tropospheric water vapor in coupled climate models compared with observations from the AIRS satellite system  

Microsoft Academic Search

Changes in the distribution of water vapor in response to anthropogenic forcing will be a major factor determining the warming the Earth experiences over the next century, so it is important to validate climate models' distribution of water vapor. In this work the three-dimensional distribution of specific humidity in state-of-the-art climate models is compared to measurements from the AIRS satellite

David W. Pierce; Tim P. Barnett; Eric J. Fetzer; Peter J. Gleckler

2006-01-01

233

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

NASA Astrophysics Data System (ADS)

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.

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

2010-09-01

234

Decadal and inter-hemispheric variability in polar mesospheric clouds, water vapor, and temperature  

NASA Astrophysics Data System (ADS)

Variability in polar mesospheric clouds (PMCs), temperature, and water vapor over decadal time scales and also between hemispheres was examined using measurements from the Halogen Occultation Experiment (HALOE) covering 1991 to present. HALOE measurements were compared to results from a zonally averaged chemical/dynamics model (CHEM2D). HALOE indicates decadal cycles in temperature, water vapor, and PMCs that are correlated with the 11-year solar cycle. During solar cycle 23, variations in temperature and water vapor were nearly identical in the north and south. Temperatures varied by roughly 5 K at 85 km to 1 K at 30 km, with colder temperatures during solar minimum. Water vapor varied by roughly 30% at 85 km to less than 1% at 30 km, with more water vapor during solar minimum. Solar cycle variations in PMC extinction were roughly 23% in both the south and north, with brighter PMCs occurring during solar minimum. The overall picture given by HALOE is consistent with expectations, where a cooler and wetter mesosphere during solar minimum corresponds to brighter PMCs. CHEM2D confirms the solar cycle variations in temperature indicated by HALOE, but underestimates the observed solar cycle changes in H2O. Comparing southern and northern HALOE measurements reveals warmer temperatures in the south throughout the mesosphere. CHEM2D results show the same pattern, although the model appears to overestimate the magnitude of these north-south differences. HALOE indicates that water vapor is nearly identical in the north and south, while CHEM2D predicts a wetter southern mesosphere. HALOE measurements show that northern PMCs are 30% brighter than southern clouds on average, a difference that must be related to the cooler northern summer mesosphere.

Hervig, Mark; Siskind, Dave

2006-01-01

235

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

SciTech Connect

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

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

2011-07-06

236

Discovery of a Water Vapor Layer in the Arctic Summer Mesosphere: Implications for Polar Mesospheric Clouds.  

National Technical Information Service (NTIS)

We report the discovery of a layer of enhanced water vapor in the Arctic summer mesosphere that was made utilizing two new techniques for remotely determining water vapor abundances. The first utilizes Middle Atmosphere High Resolution Spectrograph Invest...

C. R. Englert D. E. Siskind M. E. Summers M. H. Stevens R. R. Conway

2001-01-01

237

NEST MICROCLIMATE, WATER-VAPOR CONDUCTANCE, AND WATER LOSS IN HERON AND TERN EGGS  

Microsoft Academic Search

Rates of water loss (\\/lHo) were measured in eggs of seven species of tree- nesting Ciconiiformes and three species of ground-nesting Charadriiformes during natural incubation. Measurements of egg temperature, conductance of the egg shell to water vapor, and nest and ambient humidity allow one to calculate the difference in water-vapor pressure (Ap) between egg and nest and between nest and

CAROL MASTERS VLECK; DAVID VLECK; HERMANN RAHN; CHARLES V. PAGANELLI

238

Rapid Variability of Water Vapor Abundance in the Venus Mesosphere  

NASA Astrophysics Data System (ADS)

We present the first detections of the water vapor ground-state rotational transition (at 556.9 GHz) and the 13CO(5-4) rotational transition (at 550.9 GHz) from the atmosphere of Venus, obtained with the Submillimeter Wave Astronomy Satellite (SWAS). These submillimeter transitions originate primarily from the 70-100 km altitude range, within the Venus mesosphere. Observations were obtained in December 2002, and January, March, and July 2004, coarsely sampling one Venus diurnal period as seen from Earth. Complementary observations of the 12CO(2-1) rotational transition (at 230.5 GHz) were obtained concurrently with the Submillimeter Array (SMA) to help constrain global atmospheric parameters. The water vapor absorption line depth shows large variability among the four observing periods, with strong detections of the water line in December 2002 and July 2004, and no detections in January and March of 2004. Using a multi-transition inversion algorithm (combining temperature, carbon monoxide, and water profile retrieval under some constraints), we retrieved or found upper limits for the globally averaged mesospheric water vapor abundance for each period, finding variability over at least two orders of magnitude. The results are consistent with both temporal and diurnal variability, but with short-term fluctuations clearly dominating. The observations from December 2002 detected very rapid changes in water vapor abundance. Over five days, a deep ground-state water absorption feature consistent with a water abundance of 4.5±1.5 ppm suddenly gave way to a significantly shallower absorption, implying a decrease in the water abundance by a factor of nearly 50 in less than 48 hours. In 2004 similar changes in water vapor abundance are seen between the March and July SWAS observing periods, but variability on timescales of less than a week was not detected. M.A.G. gratefully acknowledges support from NASA contract NAG5-7946. G.J.M., V.T., E.A.B, and B.M.P. were supported by NASA contract NAS5-30702.

Gurwell, Mark A.; Melnick, G. J.; Tolls, V.; Bergin, E. A.; Patten, B. M.

2006-09-01

239

Water vapor permeability of the rigid-shelled gecko egg.  

PubMed

The vast majority of squamate reptiles (lizards and snakes) produce parchment-shelled eggs that absorb water during incubation, and thus increase in mass, volume, and surface area. In contrast, females from a single monophyletic lineage of gekkotan lizards produce rigid-shelled eggs. These eggs are functionally comparable to those of birds, that is, at oviposition, eggs contain all the water needed for development, and their mass decreases during incubation via the diffusion of water vapor through the shell. I determined patterns of water loss and shell permeability to water vapor from oviposition to hatching for the rigid-shelled eggs of the gekkonid Chrondrodactylus turneri and compared permeability of C. turneri eggs to those of birds and other squamates. Chrondrodactylus turneri eggs incubated at 28.5°C and 40% relative humidity (RH) decreased in mass by 14% over the course of a 68-day incubation period. The rate of water loss varied during incubation; egg mass decreased rapidly during the first 8 days of incubation, declined at a low constant rate during the next 35 days, and then decreased rapidly during the final 25 days of incubation. Overall permeability was 0.17 mg/day/kPa/cm(2) . Percent water loss of rigid-shelled gecko eggs during incubation is similar to that exhibited by birds, but water vapor permeability is about one-third that of bird eggs and several orders of magnitude lower than that of parchment-shelled squamate eggs. In general, the water economy of their eggs may be associated with the adaptive radiation of the rigid-shelled sphaerodactylid, phyllodactylid, and gekkonid geckos. PMID:22777731

Andrews, Robin M

2012-07-01

240

Enhanced water vapor in Asian dust layer: Entrainment processes and implication for aerosol optical properties  

Microsoft Academic Search

The entrainment process of water vapor into the dust layer during Asian dust events and the effect of water vapor associated with the Asian dust layer (ADL) on aerosol hygroscopic properties are investigated. The entrainment processes of water vapor into the ADL is examined by using a PSU\\/NCAR MM5 together with the backward trajectory model, radiosonde data, and remotely sensed

Soon-Chang Yoon; Sang-Woo Kim; Jiyoung Kim; Byung-Ju Sohn; Anne Jefferson; Suk-Jin Choi; Dong-Hyun Cha; Dong-Kyou Lee; Theodore L. Anderson; Sarah J. Doherty; Rodney J. Weber

2006-01-01

241

Tempering influence on oxygen and water vapor transmission through a stearyl alcohol film  

Microsoft Academic Search

Stearyl alcohol was layered on a filter paper support and tested for resistance to O2 and water vapor transmission following tempering. Tempering at 48C for 14 or 35 days caused the resistance to O2 and water vapor transmission to increase. The resistance to O2 and water vapor transport was increased 80% and 50% respectively, after 35 days. Likely mechanistic explanations

J. J. Kester; O. Fennema

1989-01-01

242

State of water-vapor in several kinds of gases and its effect on partial discharge  

Microsoft Academic Search

The state of water vapor in several kinds of gas molecules and its effect on partial discharge are analyzed. The state of water vapor in N 2, and O2 is found to be not much different from the state in vacuum, but the state in CO2 is quite different from the others. The state of water vapor in these gases

Y. Nagaki; T. Watabe; S. Itahashi; H. Mitsui; M. Sone

1993-01-01

243

Preparation of microporous carbon foams for adsorption\\/desorption of water vapor in ambient air  

Microsoft Academic Search

Microporous carbon foams were prepared from a fluorinated polyimide using melamine foam as a template. The adsorption\\/desorption behavior of water vapor in ambient air was examined. The activation of carbon foams at 400 °C for 1 h in air was found to be effective in increasing the adsorptivity of water vapor. The amount of water vapor adsorbed after air activation

Naoto Ohta; Yoko Nishi; Takahiro Morishita; Yumiko Ieko; Akifumi Ito; Michio Inagaki

2008-01-01

244

ASTM procedures for measurement of water vapor transmission through polymer films  

Microsoft Academic Search

Two ASTM procedures for estimating the transmission of water vapor through polymer films are compared: ASTM Standard D-1653, Standard Test Methods for Water Vapor Transmission of Organic Coating Films, and ASTM Standard E-96, Standard Test Methods for Water Vapor Transmission of Materials. Both have been identified as recognized methods for estimating performance. The objective is to ascertain whether the results

B. S. Bernstein

1993-01-01

245

Excursions into the strong precipitation regime; long tails in water vapor and other tracers (Invited)  

Microsoft Academic Search

From previous work, we know that conditional averages of precipitation undergo rapid transition to a strongly convective regime above a critical value of water vapor for a given temperature. Here we examine two aspects of how one gets into this regime. 1) Temporal relations for the water vapor, for instance preceding a high water vapor\\/convective state, using Tropical Rainfall Measuring

J. Neelin; C. E. Holloway; B. R. Lintner; B. Tian; Q. Li; L. Zhang; P. K. Patra; M. T. Chahine; S. Stechmann

2009-01-01

246

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

Microsoft Academic Search

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.

Yoram J. Kaufman; Bo-Cai Gao

1992-01-01

247

Climatic effects of atmospheric water vapor distribution through volcanic eruptions  

NASA Astrophysics Data System (ADS)

Volcanic eruptions play an important role in changing the water vapor distribution of the atmosphere. In comparison with the emission of carbon dioxide released during the consumption of fossil fuel, water vapor's role in climate change has been grossly underestimated. Studies made of modern volcanic eruptions, including satellite images and meteorological records, have revealed climatic effects in different parts of the globe through the migration of volcanic clouds, depending mainly on their timing, location, Volcanic Explosivity Index (VEI) and composition. The climatic effects of volcanic eruptions include: (1) Reduction in solar heating because of the particulates discharged. (2) Interference with the 'normal' atmospheric circulation and/or oceanic circulation. (3) The ash particles and aerosols provide condensation nuclei for water. (4) The transfer from the troposphere into the stratosphere of water vapor which act as a greenhouse gas more important than carbon dioxide. (5) Variability in regional rainfall including the occurrence of droughts, floods, landslides salinization and crop failures. (6) Anomalous regional wind and rain storms. (7) Acid rain. Selected volcanic eruptions will be used as examples to illustrate the different climatic effects.

Yim, W. W.

2011-12-01

248

New Isotopic Water Analyzer for Hydrological Measurements of Both Liquid Water and Water Vapor  

NASA Astrophysics Data System (ADS)

Measurements of the stable isotope ratios of liquid water allow determination of water flowpaths, residence times in catchments, and groundwater migration. Previously, discrete water samples have been collected and transported to an IRMS lab for isotope characterization. Due to the expense and labor associated with such sampling, isotope studies have thus been generally limited in scope and in temporal resolution. We report on the recent development of the first Isotopic Water Analyzer that simultaneously quantifies ?2H, ?17O and ?18O in liquid water or in water vapor from different natural water sources (e.g., rain, snow, streams and groundwater). In High-Throughput mode, the IWA can report measurements at the unprecedented rate of over 800 injections per day, which yields more than 140 total unknown and reference samples per day (still with 6 injections per measurement). This fast time response provides isotope hydrologists with the capability to study dynamic changes in ? values quickly (minutes) and over long time scales (weeks, months), thus enabling studies of mixing dynamics in snowmelt, canopy throughfall, stream mixing, and allows for individual precipitation events to be independently studied. In addition, the same IWA can also record fast measurements of isotopic water vapor (?2H, ?17O, ?18O) in real time (2 Hz data rate or faster) over a range of mole fractions greater than 60000 ppm H2O in air. Changing between operational modes requires a software command, to enable the user to switch from measuring liquid water to measuring water vapor, or vice versa. The new IWA, which uses LGR's patented Off-axis ICOS technology, incorporates proprietary internal thermal control for stable measurements with essentially zero drift despite changes in ambient temperature (over the entire range from 0-45 degrees C). Measurements from recent field studies using the IWA will be presented.

Owano, T.; Gupta, M.; Berman, E.; Baer, D.

2012-04-01

249

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

Microsoft Academic Search

The hydrogen isotope composition (deltaD) 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

M. Strong; Z. Sharp; D. Gutzler

2005-01-01

250

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

Microsoft Academic Search

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

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

2010-01-01

251

Sensing atmospheric water vapor with the global positioning system  

NASA Astrophysics Data System (ADS)

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 GPS satellites. Using high precision orbits, WVR-measured and GPS-inferred PWV differences between the two sites usually agreed to better than 1 mm. Using less precise on-line broadcast orbits increased the discrepancy by 30%. Data simulations show that GPS measurements can provide mm-level separate PWV estimates for the two sites, as opposed to just their difference, if baselines exceed 500 km and the highest accuracy GPS orbits are used.

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

1993-12-01

252

An automated dynamic water vapor permeation test method  

NASA Astrophysics Data System (ADS)

This report describes an automated apparatus developed to measure the transport of water vapor through materials under a variety of conditions. The apparatus is more convenient to use than the traditional test methods for textiles and clothing materials, and allows one to use a wider variety of test conditions to investigate the concentration-dependent and nonlinear transport behavior of many of the semipermeable membrane laminates which are now available. The dynamic moisture permeation cell (DMPC) has been automated to permit multiple setpoint testing under computer control, and to facilitate investigation of transient phenomena. Results generated with the DMPC are in agreement with and of comparable accuracy to those from the ISO 11092 (sweating guarded hot plate) method of measuring water vapor permeability.

Gibson, Phillip; Kendrick, Cyrus; Rivin, Donald; Charmchii, Majid; Sicuranza, Linda

1995-05-01

253

Water vapor decomposition reaction on ZrNi alloy  

Microsoft Academic Search

To develop a method for decomposing hydrogen compounds and for extracting hydrogen in only the chemical form of hydrogen molecules, a zirconium nickel (ZrNi) alloy was used to decompose water vapor. Inspection of alloy samples using X-ray diffraction spectra taken before use, midway through decomposition, and after use revealed that the ZrNi was gradually consumed and that ZrO2 and pure

Takao Kawano

2006-01-01

254

Sputtering iron oxide films by a water vapor process  

Microsoft Academic Search

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

Zeng-Jun Zhou; Jun-Jue Yan

1992-01-01

255

Lasing action in water vapor induced by ultrashort laser filamentation  

NASA Astrophysics Data System (ADS)

The water vapor fluorescence in air from filaments generated by intense ultrashort Ti:sapphire laser pulses is experimentally studied. The backscattered fluorescence from OH shows an exponential increase with increasing filament length, indicating amplified spontaneous emission. By measuring the intensity inside the filament and the fluorescence intensity of OH, a high degree of nonlinearity is obtained, indicating a highly nonlinear field dissociation of H2O molecule.

Yuan, Shuai; Wang, Tiejun; Teranishi, Yoshiaki; Sridharan, Aravindan; Hsien Lin, Sheng; Zeng, Heping; Leang Chin, See

2013-06-01

256

Sensing integrated water vapor along GPS ray paths  

Microsoft Academic Search

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

Randolph Ware; Chris Alber; Christian Rocken; Fredrick Solheim

1997-01-01

257

Water vapor adsorption on chemically treated activated carbon cloths  

Microsoft Academic Search

Water vapor adsorption on activated carbon cloth (ACC20) which has been oxidized to a level of 32% oxygen exhibits a unique isotherm with uniform hysteresis of small magnitude upon desorption. In contrast the adsorption on untreated ACC20 and chemically modified ACC20 (7.8% Cl), ACC20 (16% Cl), and ACC20 (4% N), exhibits sigmoidal isotherms with hysteresis loops of varying magnitudes. The

E. Dimotakis; J. Economy; M. Cal; M. Rood; S. Larson

1995-01-01

258

Modeling of water vapor adsorption isotherms onto polyacrylic polymer  

Microsoft Academic Search

The adsorbed amounts of water vapor onto polyacrylic polymer (polymer ×10) were measured using a thermogravimetry method as\\u000a a function of pressure at 298 and 313 K. The adsorption isotherms are categorized to type II isotherms by IUPAC classification\\u000a leading to a hysteresis loop between adsorption and desorption branches. The current study was completed by the measurement\\u000a of the adsorption heats

H. Bahaj; M. Bakass; C. Bayane; J. P. Bellat; M. Benchanaa; G. Bertrand

2011-01-01

259

Derivation of water vapor fluxes from Lidar measurements  

NASA Astrophysics Data System (ADS)

Two techniques are described by which the flux of water vapor can be derived from concentration measurements made by a Raman-Lidar. Monin-Obukhov similarity theory and dissipation techniques are used as the basis for these methods. The resulting fluxes are compared to fluxes from standard point instruments. The techniques described are appropriate for measuring the flux of any scalar quantity using Lidar measurements in the inner region of the boundary layer.

Eichinger, W. E.; Cooper, D. I.; Holtkamp, D. B.; Karl, R. R.; Quick, C. R.; Tiee, J. J.

1993-02-01

260

Metal microelectromechanical oscillator exhibiting ultra-high water vapor resolution.  

PubMed

Water vapor sensing characterization of a metal resonator fabricated with an industrial 0.35 ?m CMOS technology is reported. The resonator frequency is ?13.2 MHz and exhibits a sensitivity magnitude of ?3.5 kHz per %RH without requiring any additional hygroscopic coating layer. An on-chip integrated oscillator circuit enables an unprecedented resolution of 0.005 %RH. PMID:21748145

Verd, J; Sansa, M; Uranga, A; Perez-Murano, F; Segura, J; Barniol, N

2011-07-11

261

VCSEL based detection of water vapor near 940 nm  

Microsoft Academic Search

A vertical-cavity surface-emitting laser (VCSEL) was used to study the absorption spectrum of water vapor in the 940nm region. Measurements were performed in ambient air at room temperature and in a hydrogen–oxygen flame over the temperature range of 1500–1800K. Several rotational absorption lines within the 2?1+?3 vibrational band were measured. The absorption spectra were well resolved, which demonstrates the feasibility

Heidi Cattaneo; Toni Laurila; Rolf Hernberg

2004-01-01

262

IASI temperature and water vapor retrievals - error assessment and validation  

Microsoft Academic Search

The METOP-A satellite Infrared Atmospheric Sounding Interferometer (IASI) Level 2 products comprise retrievals of vertical profiles of temperature and water vapor. The error covariance matrices and biases of the most recent version (4.3.1) of the L2 data were assessed, and the assessment was validated using radiosonde data for reference. The radiosonde data set includes dedicated and synoptic time launches at

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

2009-01-01

263

A new high water vapor permeable polyetherurethane film dressing.  

PubMed

This study summarizes the Ph.D.-research project concerning the development of a new high water vapor permeable wound dressing. The dressing is composed of a 15 microns thin polyetherurethane (PEU) film, which has many non-interconnected cavities to enable a high water vapor permeability up to 20.1 g.m-2.h-1.kPa-1. Since only water vapor permeates through the PEU dressing, the wound exudate underneath is condensed into a gelatinous coagulum. Epithelialization was accelerated by 25% under the clot-permissive PEU film compared with the fluid retaining OpSite film. In clinical situations on donor sites and grafted full-thickness burn wounds, the PEU film indeed prevented fluid accumulation and induced the formation of a "red" coagulum underneath. It furthermore reduces pain significantly compared to conventional paraffin gauze dressing. In conclusion, the optimum environment for epithelialization is a wound, in which the exudate is permitted to gelatinize between moist and dry. PMID:2384861

Jonkman, M F; Bruin, P

1990-07-01

264

Mars atmospheric water vapor abundance: 1996-1997  

NASA Astrophysics Data System (ADS)

Measurements of martian atmospheric water vapor made throughout Ls = 18.0°-146.4° (October 3, 1996-July 12, 1997) show changes in Mars humidity on hourly, daily, and seasonal time scales. Because our observing program during the 1996-1997 Mars apparition did not include concomitant measurement of nearby CO 2 bands, high northern latitude data were corrected for dust and aerosol extinction assuming an optical depth of 0.8, consistent with ground-based and HST imaging of northern dust storms. All other measurements with airmass greater than 3.5 were corrected using a total optical depth of 0.5. Three dominant results from this data set are as follows: (1) pre- and post-opposition measurements made with the slit crossing many hours of local time on Mars' Earth-facing disk show a distinct diurnal pattern with highest abundances around and slightly after noon with low abundances in the late afternoon, (2) measurements of water vapor over the Mars Pathfinder landing site (Carl Sagan Memorial Station) on July 12, 1997, found 21 ppt ?m in the spatial sector centered near 19° latitude, 36° longitude while abundances around the site varied from as low as 6 to as high as 28 ppt ?m, and (3) water vapor abundance is patchy on hourly and daily time scales but follows the usual seasonal trends.

Sprague, A. L.; Hunten, D. M.; Doose, L. R.; Hill, R. E.

2003-05-01

265

Molecular dynamics of the water liquid-vapor interface.  

PubMed

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. PMID:11539733

Wilson, M A; Pohorille, A; Pratt, L R

1987-01-01

266

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

NASA Astrophysics Data System (ADS)

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

Karpowicz, Bryan M.; Steffes, Paul G.

2011-03-01

267

Observations of the upper tropospheric and lower stratospheric water vapor with JEM/SMILES  

NASA Astrophysics Data System (ADS)

Water vapor in the upper troposphere and lower stratosphere (UT/LS) plays a significant role in determining the weather and climate on Earth. The tropospheric water vapor acts as a dominant greenhouse gas by intensively absorbing the infrared radiation from the lower atmosphere, while its long wave emissions contribute to cooling in the stratosphere. Despite its high importance, we are still behind the thorough understanding of the distribution and climatological roles of UT/LS water vapor because of insufficient observational knowledge on them. New insight into the UT/LS water vapour can be provided by new observations with the Superconducting Submillimeter-Wave Limb-Emission Sounder, SMILES. It is a limb emission sounder to observe global atmospheric environment in the submillimeter domain, which is attached at the Japanese experiment module (JEM, a.k.a Kibo) onboard the International Space Station (ISS). Using a state-of-the-art superconductor-insulator-superconductor (SIS) mixer, an unprecedented high sensitivity such as the system temperature better than 500 K is achieved. The limb scan observations are conducted at tangential heights from -35 to 100 km, and one global map is produced per a day. Such a capability of low-tangential height sounding provides tropospheric observations with an improved horizontal resolution, and the non -sunsynchronous orbit of ISS makes it possible to observe diurnal variations of the UT/LS water vapor distribution. In this paper, the retrieval analyses of UT/LS water vapor and humidity by using the SMILES research data are presented.

Sagawa, Hideo; Kasai, Yasuko; Baron, Philippe; Mendrok, Jana; Ochiai, Satoshi; Read, William G.; Livesey, Nathaniel

268

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

269

Water vapor heterogeneity related to tropopause folds over the North Atlantic revealed by airborne water vapor differential absorption lidar  

Microsoft Academic Search

Airborne differential absorption lidar (DIAL) measurements of tropospheric water vapor and aerosol\\/clouds are presented from transfers across the North Atlantic on 13–15 May and 16–18 June 2002. The intense dynamical activity over the Atlantic is reflected in complex structures like deep tropopause folds, extended dry layers, and tilted aerosol filaments. Intrusions with H2O mixing ratios below 0.03 g kg?1 regularly

H. Flentje; A. Dörnbrack; G. Ehret; A. Fix; C. Kiemle; G. Poberaj; M. Wirth

2005-01-01

270

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

Microsoft Academic Search

Detection and measurement of atmospheric water vapor in the deep jovian atmosphere using microwave radiometry has been discussed extensively by Janssen et al. (Janssen, M.A., Hofstadter, M.D., Gulkis, S., Ingersoll, A.P., Allison, M., Bolton, S.J., Levin, S.M., Kamp, L.W. [2005]. Icarus 173 (2), 447–453.) and de Pater et al. (de Pater, I., Deboer, D., Marley, M., Freedman, R., Young, R.

Bryan M. Karpowicz; Paul G. Steffes

2011-01-01

271

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

Microsoft Academic Search

Detection and measurement of atmospheric water vapor in the deep jovian atmosphere using microwave radiometry has been discussed extensively by Janssen et al. (Janssen, M.A., Hofstadter, M.D., Gulkis, S., Ingersoll, A.P., Allison, M., Bolton, S.J., Levin, S.M., Kamp, L.W. [2005]. Icarus 173 (2), 447-453.) and de Pater et al. (de Pater, I., Deboer, D., Marley, M., Freedman, R., Young, R.

Bryan M. Karpowicz; Paul G. Steffes

2011-01-01

272

Simulation of water permeability and water vapor diffusion through hardened cement paste  

Microsoft Academic Search

The transport properties of cement-based materials significantly affect their durability. This results from the fact that most of the damaging reagents are transported, often solved in water, through the open pore space into the microstructure. This paper focuses on simulating water permeation (movement under a gradient of pressure) and water vapor diffusion (movement under a gradient of concentration) through hardened

M. Koster; J. Hannawald; W. Brameshuber

2006-01-01

273

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

Microsoft Academic Search

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

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

2010-01-01

274

Amorphous and crystalline aerosol particles interacting with water vapor - Part 1: Microstructure, phase transitions, hygroscopic growth and kinetic limitations  

Microsoft Academic Search

Interactions with water are crucial for the properties, transformation and climate effects of atmospheric aerosols. Here we outline characteristic features and differences in the interaction of amorphous and crystalline aerosol particles with water vapor. Using a hygroscopicity tandem differential mobility analyzer (H-TDMA), we performed hydration, dehydration and cyclic hydration&dehydration experiments with aerosol particles composed of levoglucosan, oxalic acid and ammonium

E. Mikhailov; S. Vlasenko; S. T. Martin; T. Koop; U. Pöschl

2009-01-01

275

An experimental study of hydrogen production by dissociation of water vapor in a radio frequency plasma source  

Microsoft Academic Search

This experiment investigates a novel technique of hydrogen production by dissociating water molecules in a radio-frequency (rf) plasma. This plasma source has a helicon antenna, capable of operating in capacitive, inductive, or helicon mode when operating conditions match those required to excite these modes. Hydrogen is produced by injecting water vapor into the plasma source. The species identified in the

S. Nguyen; K. Lemmer; A. Gallimore; J. Foster

2007-01-01

276

Some results of water vapor, ozone and aerosol balloon borne measurements during EASOE  

Microsoft Academic Search

As part of the European Arctic Stratospheric Ozone Experiment (EASOE) in the northern winter of 1991\\/92, regular measurements of the vertical distribution of ozone and aerosols were carried out from two Russian polar stations, Heiss Island (81N, 58E) and Dikson Island (73N, 81E). In addition measurements of the vertical distribution of water vapor and aerosols were made from Esrange (68N,

V. Khattatov; V. Yushkov; M. Khaplanov; I. Zaitzev; J. Rosen; N. Kjome

1994-01-01

277

Some results of water vapor, ozone, and aerosol balloon borne measurements during EASOE  

Microsoft Academic Search

As part of the European Arctic Stratospheric Ozone Experiment (EASOE) in the northern winter of 1991\\/92, regular measurements of the vertical distribution of ozone and aerosols were carried out from two Russian polar stations, Heiss Island (81N,58E) and Dikson Island (73N,81E). In addition measurements of the vertical distribution of water vapor and aerosols were made from Esrange (68N,21E), near Kiruna

V. Khattatov; V. Yushkov; M. Khaplanov; I. Zaitzev; J. Rosen; N. Kjome

1994-01-01

278

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

Microsoft Academic Search

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

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

2009-01-01

279

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

Microsoft Academic Search

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

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

2009-01-01

280

Mesospheric water vapor sounding using Earth-limb pure-rotational emission in the LWIR  

Microsoft Academic Search

Limb sounding of mesospheric water vapor using pure rotational emission in the long-wavelength infrared region has been demonstrated using data from the ELC-1 rocket experiment, launched in October, 1983. By simultaneously analyzing H2O emission at 23–29 µm and CO2 emission in the ?2 band region, effects due to uncertainties in the atmospheric temperature and instrument calibration are minimized. The H2O

Steven Adler-Golden; Piali de; Donald Smith; Anthony D'Agati

1993-01-01

281

Characterization of the TIP4PEw water model: Vapor pressure and boiling point  

Microsoft Academic Search

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

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

2005-01-01

282

Characterization of the TIP4PEw water model: Vapor pressure and boiling point  

Microsoft Academic Search

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

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

2005-01-01

283

Reply to comments on Frontiers Article ‘Behavior of hydroxide at the water/vapor interface’  

NASA Astrophysics Data System (ADS)

In this reply to comments to our Frontiers Article (B. Winter, M. Faubel, R. Vacha, P. Jungwirth Chem. Phys. Lett. 474 (2009) 241) we reiterate in detail on spectroscopic and computational evidence arguing against strong adsorption of hydroxide ions at or near the water/vapor interface. In particular, we stress that the putative strongly enhanced OH- layer within one or several nm from the surface would have been observable in our previously reported photoelectron experiments.

Winter, Bernd; Faubel, Manfred; Vácha, Robert; Jungwirth, Pavel

2009-10-01

284

Water vapor variability and comparisons in the subtropical Pacific from The Observing System Research and Predictability Experiment-Pacific Asian Regional Campaign (T-PARC) Driftsonde, Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC), and reanalyses  

NASA Astrophysics Data System (ADS)

During the THORPEX (The Observing System Research and Predictability Experiment) Pacific Asian Regional Campaign (T-PARC), from 1 August to 30 September 2008, ˜1900 high-quality, high vertical resolution soundings were collected over the Pacific Ocean. These include dropsondes deployed from four aircrafts and zero-pressure balloons in the stratosphere (NCAR's Driftsonde system). The water vapor probability distribution and spatial variability in the northern subtropical Pacific (14°-20°N, 140°E-155°W) are studied using Driftsonde and COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) data and four global reanalysis products. Driftsonde data analysis shows distinct differences of relative humidity (RH) distributions in the free troposphere between the Eastern and Western Pacific (EP and WP, defined as east and west of 180°, respectively), very dry with a single peak of ˜1% RH in the EP and bi-modal distributions in the WP with one peak near ice saturation and one varying with altitude. The frequent occurrences of extreme dry air are found in the driftsonde data with 59% and 19% of RHs less than or equal to 5% and at 1% at 500 hPa in the EP, respectively. RH with respect to ice in the free troposphere exhibits considerable longitudinal variations, very low (<20%) in the EP, but varying from 20% to 100% in the WP. Inter-comparisons of Driftsonde, COSMIC and reanalysis data show generally good agreement among the Driftsonde, COSMIC, ECMWF Reanalysis-Interim (ERA-Interim) and Japanese Reanalysis (JRA) below 200 hPa. The ERA-Interim and JRA are approved to be successful on describing RH frequency distributions and spatial variations in the region. The comparisons also reveal problems in Driftsonde, two National Center for Environmental Prediction (NCEP) reanalyses and COSMIC data. The moist layer at 200-100 hPa in the WP shown in the ERA-Interim, JRA and COSMIC is missing in Driftsonde data. Major problems are found in the RH means and variability over the study region for both NCEP reanalyses. Although the higher-moisture layer at 200-100 hPa in the WP in the COSMIC data agrees well with the ERA-Interim and JRA, it is primarily attributed to the first guess of the 1-Dimensional (1D) variational analysis used in the COSMIC retrieval rather than the refractivity measurements. The limited soundings (total 268) of Driftsonde data are capable of portraying RH probability distributions and longitudinal variability. This implies that Driftsonde system has the potential to become a valuable operational system for upper air observations over the ocean.

Wang, Junhong; Zhang, Liangying; Lin, Po-Hsiung; Bradford, Mark; Cole, Harold; Fox, Jack; Hock, Terry; Lauritsen, Dean; Loehrer, Scot; Martin, Charlie; Vanandel, Joseph; Weng, Chun-Hsiung; Young, Kathryn

2010-11-01

285

Tropospheric water vapor derived from solar spectrometer, radiometer, and GPS measurements  

NASA Astrophysics Data System (ADS)

Tropospheric water vapor is of central interest in a large variety of geoscientific fields, such as geodesy, geodynamics, climate research, and meteorology. A new instrumental approach to ground-based mapping of tropospheric water vapor has been developed. It utilizes high-resolution absorption measurements in the near-infrared region by means of a solar spectrometer (SSM). The processing algorithm for retrieval of the precipitable water vapor (PW) is based on a line-by-line calculation of the observed solar spectrum in a narrow wavelength interval (1 nm) using a simple absorption model of the troposphere. To prove the feasibility and accuracy potential of the new technique, we carried out a 30-day field experiment. Simultaneous measurements of colocated SSM, water vapor radiometers (WVR) and Global Positioning System (GPS) receivers were performed, exploiting absorption, emission and refraction properties of water vapor, respectively. A comparison of the three different techniques demonstrated the potential of solar spectrometry for precise and absolute determinaton of PW without meteorological a priori information. Apart from apparent systematic errors of the GPS measurements, a good agreement between the SSM and WVR results within their individual accuracy limits was observed. The PW standard deviations of the techniques were determined to 0.37 mm for the WVR, 0.75 mm for the SSM, and 1.40 mm for the GPS retrievals. The independence of SSM from external calibration by radiosondes and the high potential for further development may qualify this new technique to contribute to developing an error budget for other techniques, such as GPS meteorology.

Sierk, Bernd; Bürki, Beat; Becker-Ross, Helmut; Florek, Stefan; Neubert, Reinhart; Kruse, Lars Peter; Kahle, Hans-Gert

1997-10-01

286

Microwave Remote Sensing: Clouds, Precipitation, and Water Vapor  

NSDL National Science Digital Library

This module provides an introduction to polar-orbiting-satellite-based microwave remote sensing products that depict moisture and precipitation in the atmosphere. The module begins with definitions and descriptions of total precipitable water and cloud liquid water products, contrasting each with more familiar infrared water vapor and window channel products. This is followed by an overview of microwave precipitation estimation and a discussion of how polar-satellite products compare with those from geostationary satellites and ground-based radar. A series of case examples highlights potential weather forecasting applications for total precipitable water and precipitation products. The module also includes an introduction to the Global Precipitation Monitoring Mission to which future NPOESS satellites will be an important contributor. This module takes about 75 minutes to complete.

Spangler, Tim

2006-10-06

287

Some consequences of high temperature water vapor spectroscopy: water dimer at equilibrium.  

PubMed

It is shown that the evolution of water vapor spectra in the 2500-5000 cm(-1) range recorded at 650 K and pressures up to 130 atms after subtraction of monomer contribution may be interpreted qualitatively well on the basis of experimental data on water dimer and trimer obtained from cold molecular beams and in He droplets. The proposed spectroscopic model considers water vapor as a mixture of nonideal monomers, dimers, and trimers at chemical equilibrium. The effect of line mixing is taken into account in the monomer spectrum modeling. Decomposition of the high temperature spectra allowed determining a dimer equilibrium constant that was compared with the previously known values. The contribution of water trimer is assessed. The performed analysis indicates that the number of bound dimers in water vapor is quite large, even at such a high temperature. PMID:21361538

Tretyakov, M Yu; Makarov, D S

2011-02-28

288

Some consequences of high temperature water vapor spectroscopy: Water dimer at equilibrium  

NASA Astrophysics Data System (ADS)

It is shown that the evolution of water vapor spectra in the 2500-5000 cm-1 range recorded at 650 K and pressures up to 130 atms after subtraction of monomer contribution may be interpreted qualitatively well on the basis of experimental data on water dimer and trimer obtained from cold molecular beams and in He droplets. The proposed spectroscopic model considers water vapor as a mixture of nonideal monomers, dimers, and trimers at chemical equilibrium. The effect of line mixing is taken into account in the monomer spectrum modeling. Decomposition of the high temperature spectra allowed determining a dimer equilibrium constant that was compared with the previously known values. The contribution of water trimer is assessed. The performed analysis indicates that the number of bound dimers in water vapor is quite large, even at such a high temperature.

Tretyakov, M. Yu.; Makarov, D. S.

2011-02-01

289

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

NASA Astrophysics Data System (ADS)

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.

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

2008-09-01

290

A comparative study of mesospheric water vapor measurements from the ground-based water vapor millimeter-wave spectrometer and space-based instruments  

Microsoft Academic Search

We compare water vapor measurements from the Naval Research Laboratory ground- based Water Vapor Millimeter-wave Spectrometer (WVMS) instruments with measurements taken by five space-based instruments. For coincident measurements the retrievals from all of the instruments show qualitatively similar altitude profiles. The retrieved mixing ratios from most instruments generally differ from an average calculated using retrievals from all of the instruments

Gerald E. Nedoluha; Richard M. Bevilacqua; R. Michael Gomez; William B. Waltman; Brian C. Hicks; D. L. Thacker; James M. Russell; Mark Abrams; Hugh C. Pumphrey; Brian J. Connor

1997-01-01

291

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

Microsoft Academic Search

\\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

Brent R. Helliker; David Noone

292

Deuterium excess reveals diurnal sources of water vapor in forest air  

Microsoft Academic Search

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

Chun-Ta LaiJames; James R. Ehleringer

2011-01-01

293

New Isotopic Water Analyzer for Hydrological Measurements of both Liquid Water and Water Vapor  

NASA Astrophysics Data System (ADS)

Measurements of the stable isotope ratios of liquid water (?2H and ?18O) allow determination of water flowpaths, residence times in catchments, and groundwater migration. In the past, discrete water samples have been collected and transported to an IRMS lab for isotope characterization. Due to the expense and labor associated with such sampling, isotope studies have thus been generally limited in scope and in temporal resolution. We report on the recent development of a new field-portable Isotopic Water Analyzer (IWA-35EP) that accurately quantifies ?2H and ?18O of different natural water sources (e.g., rain, snow, streams and groundwater) at the unprecedented rate of 1080 injections per day, which yields 180 total unknown and reference samples per day (150 unknown samples per day), or 1 measurement of an unknown sample in less than 10 minutes (with 6 injections per measurement). This fast time response provides isotope hydrologists with the capability to study dynamic changes in ? values quickly (minutes) and over long time scales (weeks, months), thus enabling studies of mixing dynamics in snowmelt, canopy throughfall, stream mixing, and allows for individual precipitation events to be independently studied. In addition, the same IWA can also record fast measurements of isotopic water vapor (?18O and ?2H) in real time (2 Hz data rate or faster) over a range of mole fractions greater than 60000 ppm H2O in air. Changing between operational modes requires a software command, to enable the user to switch from measuring liquid water to measuring water vapor, or vice versa. The new IWA, which uses LGR's patented Off-axis ICOS technology, incorporates proprietary internal thermal control for stable measurements with essentially zero drift. Measurements from recent field studies using the IWA will be presented.

Owano, T. G.; Gupta, M.; Dong, F.; Baer, D. S.

2011-12-01

294

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

SciTech Connect

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

Braun, John

2006-02-06

295

SCIAMACHY Lunar Occultation Water Vapor Retrieval & Validation For The Southern Hemispheric Stratosphere  

NASA Astrophysics Data System (ADS)

SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY) onboard the European Space Agency's ENVIronmental SATellite (ENVISAT) observes the earth's atmosphere in nadir, limb and solar/lunar occultation geometry covering the UV to NIR (240nm -2380nm) spectral range. The instrument is dedicated to improve our knowl-edge in atmospheric composition and global atmospheric change serving the needs for climate monitoring. The instrument thereby provides total columns as well as vertical profiles of the climate parameters that are relevant to the ozone chemistry, air pollution and global climate change issues, from the troposphere upto the mesosphere. The water vapor has a longer chemical lifetime in the stratosphere and in the polar region it accounts for the chemistry and dynamics. The amount of water vapor in the polar stratosphere directly influence the ozone depletion by controlling the polar vortex temperatures and the formation temperature of the polar stratospheric clouds. From the lunar transmission spectra measured by SCIAMACHY from 2003 to present, stratospheric number density profiles of water vapor have been retrieved over the high southern latitudes ( 50° S -90° S ). The H2 O profiles are retrieved in the altitude range 17-50 km from the calibrated level-1 data using the spectral window 1350-1420 nm. To access the quality and accuracy of this H2 O prod-uct, the validation has been carried out using the correlative solar occultation spectra measured by other instruments such as the satellite instrument ACE-FTS (Atmospheric Chemistry Ex-periment Fourier Transform Spectrometer) and HALOE (HALogen Occultation Experiment). The lunar occultation water vapor retrieval, optimization and the results of the comparisons are presented here. For the Antarctic region, there is a coverage scarcity of the atmospheric species which play significant role in the chemistry and dynamics associated with the polar vortex and the ozone hole by the satellite or ground based instruments. A validated dataset of H2 O vertical distribution retrieved from SCIAMACHY lunar occultation measurements is expected to facilitate the understanding of the physical and chemical processes in the southern hemi-sphere and will add as the southern hemispheric measurement coverage to the SCIAMACHY longterm global water vapor time series. First steps towards the interpretation and analysis of water vapor distribution in the southern mid latitudes and the Antarctic region are highlighted in the presented study.

Azam, Faiza; Bramstedt, Klaus; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John P.

296

Temperature-regulated 22 GHz water vapor radiometers for CARMA  

NASA Astrophysics Data System (ADS)

The Combined Array for Research in Millimeter-wave Astronomy (CARMA) have carried out a water vapor radiometer (WVR) project to test the WVR phase correction technique for better observational effciency. We have built two uncooled, but temperature-regulated, 22 GHz WVR prototypes to explore the feasibility of the technique. To better isolate the effects of instrumental and atmospheric instabilities, we have optimized theWVR design for simplicity with less high frequency components. The calibration system is Dicke switch with a single ambient load. The thermal regulation system consists of heaters and multi-stage insulation. We have completed testing of the WVR prototypes in a laboratory and at the CARMA site. The gain stability is about 20-100 mK and the front-end temperature rms is about a few mK to hundreds, depending on weather conditions. Based on the site tests, the sky temperature at 22 GHz usually varies a few K in 15 minutes, which is not necessary due to the atmospheric water vapor. Such short time-scale background temperature variation overwhelms the limit of the WVR dynamic range. Moreover, we have compared the WVR data rms with the phase monitor at the site and obtain a scale factor of the 22 GHz water vapor line, 6-12, which is consistent with the results of other WVR projects. We suggest that expanding the WVR dynamic range with diode detector models and a better thermal regulation system are keys to the success of the CARMA WVR phase correction.

Shiao, Y.-S. Jerry; Looney, Leslie W.

2008-08-01

297

Far-Infrared Emission Spectroscopy of Rovibrationaly Excited Water Vapor  

NASA Astrophysics Data System (ADS)

Water vapor transitions involving excited rov|ibrational levels have been identified in many high temperature space sources. Extensive experimental and theoretical efforts are still needed to provide more accurate databases concerning highly excited rovibrational levels. In this context, the high resolution emission spectrum of water vapor has been recorded between 50 and 600 cm-1 using a Bruker IFS 125HR Fourier transform interferometer and a continuous flow of water vapor rovibrationaly excited by an electrodless radio-frequency discharge. More than 1500 pure rotational lines were assigned within the fundamental (000) and first excited (010) vibrational states up to J=35. Rotational as well as rovibrational lines were identified for the higher lying states up to the first hexad. About 1000 pure rotational transitions within the vibrational states of the first hexad were assigned for the first time. The new data, along with a large body of high-resolution data, was fitted using the bending-rotation theoretical approach to compute line positions. In a preliminary analysis, the wavenumbers of 1511 new transitions involving the ground and (010) states were accounted for up to J=27 with a root mean square value of 0.8× 10-3 cm-1. Work is still in progress and we are hoping to account for the new data at least up to the second triad. In the paper the new data will be presented and the results of the line position analysis will be given. Pirali and Vervloet, Chem. Phys. Letters 423 (2006) 376. Coudert, Wagner, Birk, Baranov, Lafferty, and Flaud, J. Mol. Spec. 251 (2008) 339. Coudert, J. Mol. Spec. 181 (1997) 246.

Martin, M.-A.; Pirali, O.; Balcon, D.; Vervloet, M.; Coudert, L. H.

2010-06-01

298

Comparison of precipitable water vapor measurements obtained by microwave radiometry and radiosondes at the Southern Great ...  

SciTech Connect

Comparisons between the precipitable water vapor (PWV) estimated by passive microwave radiometers (MWRs) and that obtained by integrating the vertical profile of water vapor density measured by radiosondes (BBSS) have generally shown good agreement. These comparisons, however, have usually been done over rather short time periods and consequently within limited ranges of total PWV and with limited numbers of radiosondes. We have been making regular comparisons between MWR and BBSS estimates of PWV at the Southern Great Plains Cloud and Radiation Testbed (SGP/CART) site since late 1992 as part of an ongoing quality measurement experiment (QME). This suite of comparisons spans three annual cycles and a relatively wide range of total PWV amounts. Our findings show that although for the most part the agreement is excellent, differences between the two measurements occur. These differences may be related to the MWR retrieval of PWV and to calibration variations between radiosonde batches.

Lesht, B.M. [Argonne National Lab., IL (United States); Liljegren, J.C. [Pacific Northwest Lab., Richland, WA (United States)

1996-12-31

299

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

SciTech Connect

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.

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

300

Inter-comparison of three commercial instruments for water vapor isotope measurement  

NASA Astrophysics Data System (ADS)

The ?18O and ?D of atmospheric water vapor provide rich information on the hydrological cycle and gaseous exchange processes between the terrestrial vegetation and the atmosphere. In the past, the majority of water vapor isotope studies have relied on discrete sampling using cold-trap/mass spectrometry methods. Recent development of isotope ratio infrared spectroscopy (IRIS) has made it possible to make in-situ, continuous observations of the ?18O and ?D of atmospheric water vapor. In this paper, we report the results of an inter-comparison experiment using three commercial IRIS analyzers. These analyzers were developed on the basis of tunable diode laser absorption spectroscopy (model TGA100A, Campbell Scientific Inc., Logan, UT), off-axis integrated cavity output spectroscopy (model DLT-100, Los Gatos Research, Mountain View, CA) and wavelength-scanned cavity ring-down spectroscopy (models L1115-i and L1102-i, Picarro Inc., Sunnyvale, CA). Each analyzer was calibrated, at factory recommended frequencies, with its own calibration device traceable to the same working standard. The experiment consisted of two parts each lasting 2 weeks. First, the ?18O and ?D of ambient water vapor from a common intake were measured simultaneously with these analyzers. The data reported for hourly intervals were analyzed to reveal how well these analyzers track natural variability in ambient conditions. Second, a home-made bubbler combined with dry air was used for performance evaluation under controlled conditions. The bubbler produced a moisture stream that followed the Rayleigh prediction, and with appropriate mixing with dry air provided a sufficient range of humidity at preset levels of mixing ratio (30,000, 20,000, 10,000, 5,000 ppm). Analysis of the experimental data is underway to (1) evaluate the relative precision and accuracy among these analyzers, (2) compare the measured isotopic ratios against the Rayleigh prediction, and (3) identify appropriate calibration frequencies for long-term unattended operation.

Wen, X.; Sun, X.; Li, S.; Lee, X.

2010-12-01

301

Three-channel solar radiometer for the determination of atmospheric columnar water vapor.  

PubMed

The design of a three-channel solar radiometer used to determine total columnar atmospheric water-vapor amounts is presented. The main channel is located in the 0.94-µm water-vapor band, and two other channels are located in adjacent nonabsorption regions of the solar spectrum and are used to remove scattering effects from the main channel. Water-vapor transmittance is determined by means of a modified Langley approach, and these transmittances are converted to columnar water vapor by means of a band model developed at the University of Arizona. Several cases are presented in which columnar water-vapor amounts are determined through the use of the instrument and method described here. These results are compared with sounding-balloon results. Tests of the method indicate that columnar water vapor may be retrieved with an uncertainty of less than 10%. PMID:20935984

Thome, K J; Smith, M W; Palmer, J M; Reagan, J A

1994-08-20

302

An Intercomparison of Water Vapor Measurements in the TTL and Lower Tropical Stratosphere during CRAVE and TC4: The Importance and Implications of Laboratory Calibrations With water Vapor Mixing Ratios From 0-10 ppmv.  

NASA Astrophysics Data System (ADS)

As part of the effort to validate instruments on the Aura satellite, the Costa Rica Aura Validation Experiment (CRAVE) was flown in January and February of 2006. Systematic differences in measured water vapor in the tropopause region and lower stratosphere between in situ instruments on the WB57, the NOAA Colorado frostpoint hygrometer (CFH) and satellite borne instruments such as the Microwave Limb Sounder (MLS) and the Halogen Occultation Experiment (HALOE) are well-documented. Results from CRAVE, presented during a water vapor workshop organized as part of the CRAVE science meeting, provided further confirmation of these differences. The availability for the first time of multiple robust intercomparisons between these instruments led to the conclusion that at low water mixing ratios (less than 10 ppmv), the differences appear to be well-represented by an offset of about 2 ppmv with in situ instruments on the WB57 measuring higher than MLS and CFH. This enduring discrepancy precludes a satisfactory validation of satellite retrievals of stratospheric water vapor profiles. In this talk we will summarize the recent low water calibration runs in our laboratory that provide direct evidence that the Harvard Lyman alpha instrument measures accurately at low water. We will then compare data taken during the recent TC4 campaign in August 2007 with that from CRAVE and previous campaigns. The implications of the results on our understanding of the mechanisms that control the stratospheric water vapor budget will be discussed.

Weinstock, E. M.; Smith, J. B.; Hanisco, T. F.; Sayres, D. S.; St. Clair, J. M.; O'Brien, A.; Anderson, J. G.

2007-12-01

303

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

Microsoft Academic Search

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

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

1995-01-01

304

Tropospheric water vapor imaging by combination of ground-based and spaceborne GNSS sounding data  

NASA Astrophysics Data System (ADS)

The Global Navigation Satellite System (GNSS) comprises the U.S. system GPS (Global Positioning System), its Russian pendant GLONASS, and presumably, in the future, the European system Galileo. The potential of GNSS-based phase delay measurements for accurately estimating vertically and slant-path-integrated water vapor has been demonstrated recently for radio links between GPS satellites and ground-based GPS receivers. GNSS-based radio occultation, on the other hand, has been demonstrated via the GPS/Meteorology experiment to deliver accurate near-vertical profiles of atmospheric variables such as temperature and humidity with high vertical resolution. Height-resolving imaging of atmospheric water vapor becomes feasible when occultation profiles from spaceborne receivers in Low Earth Orbits (LEO) are combined with ground-based GNSS data from a colocated receiver network. We developed a two-dimensional, height-resolving tomographic imaging technique following the Bayesian approach for optimal combination of information from different sources. Using simulated GNSS-based water vapor measurements from LEO and ground, we show representative results derived from simple synthetic refractivity fields as well as from a realistic refractivity field based on a European Centre for Medium-Range Weather Forecasts (ECMWF) analysis. For cases located poleward of ˜40° we found a new simple mapping function to perform best within our forward model scheme, where the only free parameter is the climatological scale height in the troposphere, the exact value of which is not critical. The mapping function exploits the ratio between the straight-line ray path length within the first two scale heights above surface and the "effective height" defined by these first two scale heights. We found our technique capable of reconstructing atmospheric features like water vapor maxima near the top of the trade wind inversion. Adjustment of the integral over the water vapor profile measurements to the horizontally averaged ground-based vertical integrated water vapor data efficiently mitigates potential biases in the former data. Accuracies are best in areas with high absolute humidities but also over drier areas such as Finland, useful two-dimensional information can still be obtained. Thus it is attractive to apply the developed technique in a next step to real data.

Foelsche, Ulrich; Kirchengast, Gottfried

2001-11-01

305

Homogeneous nucleation rate measurements in supersaturated water vapor  

NASA Astrophysics Data System (ADS)

The rate of homogeneous nucleation in supersaturated vapors of water was studied experimentally using a thermal diffusion cloud chamber. Helium was used as a carrier gas. Our study covers a range of nucleation rates from 3×10-1 to 3×102 cm-3 s-1 at four isotherms: 290, 300, 310, and 320 K. The molecular content of critical clusters was estimated from the slopes of experimental data. The measured isothermal dependencies of nucleation rate of water on saturation ratio were compared with the prediction of the classical theory of homogeneous nucleation, the empirical prediction of Wölk et al. [J. Chem. Phys. 117, 10 (2002)], the scaled model of Hale [Phys. Rev. A 33, 4156 (1986)], and the former nucleation onset data.

Brus, David; Ždímal, Vladimír; Smolík, Ji?í

2008-11-01

306

IASI temperature and water vapor retrievals - error assessment and validation  

NASA Astrophysics Data System (ADS)

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

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

2009-03-01

307

IASI temperature and water vapor retrievals - error assessment and validation  

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

308

Numerical modeling of water injection into vapor-dominatedgeothermal reservoirs  

SciTech Connect

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.

Pruess, Karsten

2006-11-06

309

Observations of water vapor by ground-based micro-wave radiometers and Raman lidar  

NASA Astrophysics Data System (ADS)

In November to December 1991, a substantial number of remote sensors and in situ instruments were operated together in Coffeyville, Kansas, during the climate experiment FIRE II. Included in the suite of instruments were (1) the NOAA Environmental Technology Laboratory (ETL) three-channel microwave radiometer, (2) the NASA GSFC Raman lidar, (3) ETL radio acoustic sounding system (RASS), and (4) frequent, research-quality radiosondes. The Raman lidar operated only at night and the focus of this portion of the experiment concentrated on clear conditions. The lidar data, together with frequent radiosondes and measurements of temperature profiles (every 15 min) by RASS allowed profiles of temperature and absolute humidity to be estimated every minute. We compared 2-min measurements of brightness temperature (Tb) with calculations of Tb that were based on the Liebe and Lay ton (1987) and Liebe et al. (1993) microwave propagation models, as well as the Waters (1976) model. The comparisons showed the best agreement at 20.6 GHz with the Waters model, with the Liebe et al. (1993) model being best at 31.65 GHz. The results at 90 GHz gave about equal success with the Liebe and Layton (1987) and Liebe et al. (1993) models. Comparisons of precipitable water vapor derived independently from the two instruments also showed excellent agreement, even for averages as short as 2 min. The rms difference between Raman and radiometric determinations of precipitable water vapor was 0.03 cm which is roughly 2%. The experiments clearly demonstrate the potential of simultaneous operation of radiometers and Raman lidars for fundamental physical studies of water vapor.

Han, Yong; Snider, J. B.; Westwater, E. R.; Melfi, S. H.; Ferrare, R. A.

1994-09-01

310

Stratospheric water vapor trends over Boulder, Colorado: Analysis of the 30 year Boulder record  

Microsoft Academic Search

Trend analyses are presented for 30 years (1980–2010) of balloon-borne stratospheric water vapor measurements over Boulder, Colorado. The data record is broken into four multiple-year periods of water vapor trends, including two that span the well-examined but unattributed 1980–2000 period of stratospheric water vapor growth. Trends are determined for five 2 km stratospheric layers (16–26 km) utilizing weighted, piecewise regression

Dale F. Hurst; Samuel J. Oltmans; Holger Vömel; Karen H. Rosenlof; Sean M. Davis; Eric A. Ray; Emrys G. Hall; Allen F. Jordan

2011-01-01

311

Comparison of Columnar Water-Vapor Measurements from Solar Transmittance Methods  

Microsoft Academic Search

In the fall of 1997 the Atmospheric Radiation Measurement program conducted a study of water-vapor-abundance-measurement at its southern Great Plains site. The large number of instruments included four solar radiometers to measure the columnar water vapor (CWV) by measuring solar transmittance in the 0.94- m water-vapor absorption band. At first, no attempt was made to standardize our procedures to the

Beat Schmid; Joseph J. Michalsky; Donald W. Slater; James C. Barnard; Rangasayi N. Halthore; James C. Liljegren; Brent N. Holben; Thomas F. Eck; John M. Livingston; Philip B. Russell; Thomas Ingold; Ilya Slutsker

2001-01-01

312

Linkages Among Water Vapor Flows, Food Production, and Terrestrial Ecosystem Services  

Microsoft Academic Search

Global freshwater assessments have not addressed the linkages among water vapor flows, agricultural food production, and terrestrial ecosystem services. We perform the first bottom-up estimate of continental water vapor flows, subdivided into the major terrestrial biomes, and arrive at a total continental water vapor flow of 70,000 km3\\/yr (ranging from 56,000 to 84,000 km3\\/yr). Of this flow, 90% is attributed

Johan Rockström; Line Gordon; Carl Folke; Malin Falkenmark; Maria Engwall

2009-01-01

313

Atmospheric water vapor transport associated with typical anomalous summer rainfall patterns in China  

NASA Astrophysics Data System (ADS)

This paper attempts to reveal the atmospheric water vapor transports associated with typical anomalous summer rainfall patterns in China. The results show that origins of water vapor supply related to anomalous rainfall patterns are different from those related to the normal monsoon rainfall. Anomalous pattern 1, with a heavier rainbelt along the middle and lower reaches of the Yangtze River valley, follows from a convergence of the tropical southwest water vapor transport with the midlatitude northeast water vapor transport; the tropical water vapor transport comes directly from the Bay of Bengal and the South China Sea but originally from the Philippine Sea. The anomalous water vapor transport is associated with a southwestward extension of the western Pacific subtropical high and a southward shift of the upper East Asian jet stream. Anomalous pattern 2, with a main rainbelt along the Huaihe River valley, is supported by the convergence of the subtropical southwest water vapor with the midlatitude water vapor transport. The subtropical branch comes directly from the South China Sea but originally from the East China Sea and the adjacent subtropical Pacific to the further east along 20-25°N. The background large-scale circulation change includes a northwestward extension of the western Pacific subtropical high and an eastward shift of the upper jet stream. Although the cross-equator flows including the Somali jet supply abundant water vapor for the normal condition of June, July, and August rainfall over China, the tropical water vapor transports related to typical anomalous rainfall anomalies originate from the tropical western Pacific Ocean. The northward transport of anomalous warm water vapor occurs mainly in the lower troposphere, while the transport of midlatitude cold water vapor occurs briefly in the upper troposphere.

Zhou, Tian-Jun; Yu, Ru-Cong

2005-04-01

314

Water Vapor Radiometer-Global Positioning System Comparison Measurements and Calibration of the 20 to 32 Gigahertz Tropospheric Water Vapor Absorption Model  

NASA Astrophysics Data System (ADS)

Collocated measurements of opacity (from water vapor radiometer (WVR) brightness temperatures) and wet path delay (from ground-based tracking of Global Positions System (GPS) satellites) are used to constrain the model of atmospheric water vapor absorption in the 20 to 32 GHz band. A differential approach is presented in which the slope of opacity-versus-wet delay data is used as the absorption model constraint. This technique minimizes the effects of radiometric calibration errors and oxygen model uncertainties in the derivation of a best-fit vapor absorption model. A total of approximately 5 months of data were obtained from two experiment sites. At the Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma, three independent WVRs provided near-continuous opacity measurements over the interval from July through September 1998. At NASA's Goldstone tracking station in the California desert, two WVRs obtained opacity data over the September through October 1997 interval. At both sites, a GPS receiver and surface barometer obtained the data required for deriving the zenith wet delays over the same time frames. Measured values of the opacity-versus-wet delay slope parameter were obtained at four WVR frequencies (20.7, 22.2, 23.8, and 31.4 GHz) and compared with predictions of three candidate absorption models referenced in the recent literature. With one exception, all three models provide agreement within approximately 5 percent of the opacity-versus-wet delay slope measurements at all WVR frequencies at both sites. One model provides agreement for all channels at both sites to the 2 to 3 percent level. This accuracy is sufficient to meet the requirements of the tropospheric calibration system now being deployed at Goldstone to support the Cassini Gravitational Wave Experiment.

Keihm, S. J.; Bar-Sever, Y.; Liljegren, J.

2000-10-01

315

In search of water vapor on Jupiter: Laboratory measurements of the microwave properties of water vapor and simulations of Jupiter's microwave emission in support of the Juno Mission  

NASA Astrophysics Data System (ADS)

This research has involved the conduct of a series of laboratory measurements of the centimeter-wavelength opacity of water vapor along with the development of a hybrid radiative transfer ray-tracing simulator for the atmosphere of Jupiter which employs a model for water vapor opacity derived from the measurements. For this study an existing Georgia Tech high-sensitivity microwave measurement system (Hanley and Steffes, 2007) has been adapted for pressures ranging from 12--100 bars, and a corresponding temperature range of 293--525°K. Water vapor is measured in a mixture of hydrogen and helium. Using these measurements which covered a wavelength range of 6--20 cm, a new model is developed for water vapor absorption under Jovian conditions. In conjunction with our laboratory measurements, and the development of a new model for water vapor absorption, we conduct sensitivity studies of water vapor microwave emission in the Jovian atmosphere using a hybrid radiative transfer ray-tracing simulator. The approach has been used previously for Saturn (Hoffman, 2001), and Venus (Jenkins et al., 2001). This model has been adapted to include the antenna patterns typical of the NASA Juno Mission microwave radiometer (NASA/Juno-MWR) along with Jupiter's geometric parameters (oblateness), and atmospheric conditions. Using this adapted model we perform rigorous sensitivity tests for water vapor in the Jovian atmosphere. This work will directly improve our understanding of microwave absorption by atmospheric water vapor at Jupiter, and improve retrievals from the Juno microwave radiometer. Indirectly, this work will help to refine models for the formation of Jupiter and the entire solar system through an improved understanding of the planet-wide abundance of water vapor which will result from the successful opreation of the Juno Microwave Radiometer (Juno-MWR).

Karpowicz, Bryan Mills

316

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

Microsoft Academic Search

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

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

2006-01-01

317

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

Microsoft Academic Search

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.

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

1990-01-01

318

Continuous and selective determination of water vapor evolved during thermal decomposition reactions  

Microsoft Academic Search

A method suitable for the continuous and selective determination of water vapor evolved during thermal decomposition processes is described. The water detector can be connected to thermoanalytical equipment of controlled gas atmosphere without any difficulty. Water vapor, together with other gaseous decomposition products, is collected by the carrier gas and transported through a glass reaction vessel containing the measuring and

J. Kristóf; J. Inczédy; J. Paulik; R Paulik

1991-01-01

319

Dynamics of water-vapor absorption by a quartz fiber lightguide when it is being drawn  

Microsoft Academic Search

This paper presents data concerning two processes by which a quartz fiber lightguide interacts with water vapor. When a lightguide is fabricated, the moving fiber can adsorb water vapor from the ambient atmosphere, and, after a metallic leak-proof cladding has been formed, a process occurs by which water molecules migrate into the bulk of the quartz glass. The latter is

V. S. Shevandin

2006-01-01

320

The Effect of Water Vapor on the Particle Structure and Size of Silica Nanoparticles during Sintering  

Microsoft Academic Search

The influence of the water vapor concentration on structural changes of SiO2 aerosol nanoparticle agglomerates during tempering was studied. The presence of water vapor in the carrier gas was shown to strongly accelerate the kinetics of sintering. While dry sintering at temperatures between 1100 and 1500°C generated aggregates only, the addition of water to the process yields individual, completely coalesced

Verena Goertz; Frederik Weis; Elena Keln; Hermann Nirschl; Martin Seipenbusch

2011-01-01

321

Absorption coefficients for water vapor at 193 nm from 300 to 1073 K  

Microsoft Academic Search

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

W. J. Kessler; K. L. Carleton; W. J. Marinelli

1993-01-01

322

Evaluation of spectroscopic databases of water vapor between 585 and 600 nm  

Microsoft Academic Search

The water vapor absorption band between 585 and 600 nm is suitable for atmospheric water vapor column retrieval from satellite data because saturation effects are absent and water is the only significant structured absorber within this region. Accurate knowledge of the absorption spectroscopy is important for the retrieval as well as for assessing radiative forcing. Spectral databases for this wavelength

B. Veihelmann; R. Lang; K. M. Smith; D. A. Newnham; W. J. van der Zande

2002-01-01

323

Validation of line-of-sight water vapor measurements with GPS  

NASA Astrophysics Data System (ADS)

We present a direct comparison of nonisotropic, integrated water vapor measurements between a ground-based Global Positioning System (GPS) receiver and a water vapor radiometer (WVR). These line-of-sight water vapor observations are made in the straight line path between a ground station and a GPS satellite. GPS double-difference observations are processed, and the residual line-of-sight water vapor delays are extracted from the double-difference residuals. These water vapor delays contain the nonisotropic component of the integrated water vapor signal. The isotropic component is represented by the zenith precipitable water vapor measurement and can be scaled to a specific elevation angle based on a mapping function. The GPS observations are corrected for station-dependent errors using site-specific multipath maps. The resulting measurements are validated using a WVR which pointed in the direction of the observed satellites. The double-difference technique used to make these water vapor observations does not depend on accurate satellite clock estimates. Therefore it is especially well suited for near-real-time application in weather prediction and allows for sensing atmospheric structure that is below the noise level of current satellite and receiver clock errors. This paper describes the analysis technique and provides precision estimates for the GPS-measured nonisotropic water vapor as a function of elevation angle for use with data assimilation systems.

Braun, John; Rocken, Christian; Ware, Randolph

2001-05-01

324

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

SciTech Connect

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

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

1990-09-01

325

Accurate measurements of water vapor transmission through high-performance barrier layers  

NASA Astrophysics Data System (ADS)

We report a new approach to measuring very low rates of water vapor transmission through high-performance barrier layers, based on detection of the water vapor by cavity ring-down infrared spectroscopy. It provides accurate and traceable measurements with a detection limit for water vapor transmission significantly below 1 × 10-4 g/m2/day. The system is underpinned by dynamic reference standards of water vapor generated between 5 and 2000 nmol/mol with an estimated relative expanded uncertainty of +/-2%. It has been compared with other methods and demonstrates good comparability.

Brewer, P. J.; Goody, B. A.; Kumar, Y.; Milton, M. J. T.

2012-07-01

326

An Intercomparison of Water Vapor Measurements in the TTL and Lower Tropical Stratosphere during CRAVE and TC4: The Importance and Implications of Laboratory Calibrations With water Vapor Mixing Ratios From 0-10 ppmv  

Microsoft Academic Search

As part of the effort to validate instruments on the Aura satellite, the Costa Rica Aura Validation Experiment (CRAVE) was flown in January and February of 2006. Systematic differences in measured water vapor in the tropopause region and lower stratosphere between in situ instruments on the WB57, the NOAA Colorado frostpoint hygrometer (CFH) and satellite borne instruments such as the

E. M. Weinstock; J. B. Smith; T. F. Hanisco; D. S. Sayres; J. M. St. Clair; A. O'Brien; J. G. Anderson

2007-01-01

327

Water Vapor Radiometer for ALMA: Optical Design and Verification  

NASA Astrophysics Data System (ADS)

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.

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

2010-03-01

328

Experiment in Water Dowsing.  

National Technical Information Service (NTIS)

Dowsing is a folklore process used to locate an unknown, such as the best location for a water well, by the use of a hand-held device. The process is commonly know as water witching, divining, dowsing or radiesthesia. The practice continues despite the la...

D. I. Gaisford

1994-01-01

329

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

SciTech Connect

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

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

1995-02-01

330

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

NASA Astrophysics Data System (ADS)

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.

Wang, Wei; Liu, Wenqing; Zhang, Tianshu

2012-12-01

331

CRISTA-NF measurements of water vapor during the SCOUT-O3 Tropical Aircraft Campaign  

NASA Astrophysics Data System (ADS)

The new remote sensing experiment CRISTA-NF (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere New Frontiers) successfully participated in the SCOUT-O3 Tropical Aircraft Campaign in November and December 2005. CRISTA-NF operated aboard the high-altitude research aircraft M-55 Geophysica. Mid-infrared spectra (4 15 ?m) were measured in the limb sounding geometry with high spatial resolution (250 m vertical sampling, 5 15 km along track sampling). Measurements were carried out during transfer flights between Oberpfaffenhofen, Germany, and Darwin, Australia, as well as during several local flights near Darwin. Water vapor volume mixing ratios in the upper troposphere and lower stratosphere were derived from the CRISTA-NF radiance measurements by utilizing a rapid radiative transfer forward model and the optimal estimation retrieval approach. CRISTA-NF water vapor measurements below the hygropause have a total retrieval error of 15 40% (i.e. root mean square of accuracy and precision). The systematic terms are dominating in the retrieval error budget. The contributions of a priori information to the retrieval results are less than 5 10%. The vertical resolution of the observations is about 250 500 m when permitted by instrument sampling. In this paper we present first results for three transfer flights of the campaign. Being generally in good agreement with corresponding ECMWF operational analyzes, the CRISTA-NF measurements show significantly higher variability and local structures in the upper tropospheric water vapor distributions.

Hoffmann, L.; Weigel, K.; Spang, R.; Schroeder, S.; Arndt, K.; Lehmann, C.; Kaufmann, M.; Ern, M.; Preusse, P.; Stroh, F.; Riese, M.

2009-01-01

332

SAGE II Version 6.3: Improved ozone and water vapor data products  

NASA Astrophysics Data System (ADS)

A new version for the Stratospheric Aerosol and Gas Experiment (SAGE II) data products has been developed and is in the process of being released. This version incorporates the transmission refinements developed for SAGE III Version 4 that reduces uncertainty in the multi-wavelength line-of-sight transmission data. The transmission profiles form the backbone of the SAGE II retrievals of ozone, NO2, water vapor, and multi-wavelength aerosol extinction. In addition, we have updated the SAGE II ozone and NO2 spectroscopic data to match those used in the SAGE III retrievals. The change in spectroscopy, required a reassessment of the spectral characteristics of the water vapor channel located near 940 nm with an end result that SAGE II water vapor is in much better agreement with MLS and SAGE III than in version 6.2 and remains so over a larger altitude range than was previously noted. Finally, we have reassessed the estimation of dark current in SAGE II data stream with an outcome that the well-known bias in SAGE II ozone in the troposphere is significantly reduced.

Damadeo, R. P.; Thomason, L. W.; Zawodny, J. M.; Iyer, N.

2011-12-01

333

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

NASA Astrophysics Data System (ADS)

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

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

334

Nuclear Quantum Effects Affect Bond Orientation of Water at the Water-Vapor Interface  

NASA Astrophysics Data System (ADS)

Using combined theoretical and experimental approaches, we demonstrate that the bond orientation of water at the water-vapor interface depends markedly on the water isotope (H-D) composition. While the interfacial water structures of H2O and D2O are indistinguishable, the intramolecular symmetry breaking in HDO is directly reflected at the surface: the OD bonds preferably orient down towards the bulk water, whereas the OH bond tends to orient up into the vapor phase. Path integral molecular dynamics simulations show good agreement with surface-specific sum-frequency generation (SFG) spectroscopy results, revealing that the distinct interfacial bond orientations originate from nuclear quantum effects. The enhanced localization of the heavier D atom leads to stronger hydrogen bonds, giving rise to OD bonds pointing down into the bulk.

Nagata, Yuki; Pool, Ruben E.; Backus, Ellen H. G.; Bonn, Mischa

2012-11-01

335

Mesospheric Water Vapor Sounding Using Earth-Limb Pure-Rotational Emission in the LWIR. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

Limb sounding of mesospheric water vapor using pure rotational emission in the long-wavelength infrared region has been demonstrated using data from the ELC-1 rocket experiment, launched in October, 1983. By simultaneously analyzing H2O emission at 23-29 ...

S. Adler-Golden P. De D. Smith A. D'Agati

1993-01-01

336

Some problems in the calculation and measurement of the absorption of millimeter and submillimeter waves in atmospheric water vapor  

Microsoft Academic Search

Recent measurements of the absorption coefficient of water vapor in the transparent windows of the submillimeter wave region (X > 60g) exceed earlier calculated values by a factor of 1.5-2, i.e., there is a discrepancy between theory and experiment similar to that existing in the millimeter wave region (2 ~< <~k~< 8 mm) A short discussion is given of the

S. A. Zhevakin; A. P. Naumov

1965-01-01

337

High resolution acetic acid survey and water vapor radiometer  

NASA Astrophysics Data System (ADS)

Planets, comets, stars, galaxies and the interstellar medium (ISM) emit complex but distinct molecular spectra. These spectra reveal the chemical composition and physical conditions in the objects. For example, many biologically important molecules, such as acetic acid, formic acid, vinyl cyanide and ethyl cyanide, have been detected in hot molecular cores in the ISM. A diversity of molecules creates complicated and yet interesting astrochemistry in hot cores. However, the formation mechanisms of large molecules are still unclear. Hence large molecule observations are essential to understand hot core chemistry. Among these molecules, acetic acid is one of the most important large species in hot cores. It is a possible precursor of glycine, the simplest amino acid. It only has been detected in high-mass hot cores without oxygen/nitrogen chemical differentiation, which is key to hot core chemical models. Using the Combined Array for Research in Millimeter-wave Astronomy (CARMA), we have conducted an acetic acid survey in hot cores. In our survey, we have discovered a new acetic acid hot core, G19.61-0.23, which also shows no chemical differentiation. Therefore, we suggest that both large oxygen and nitrogen- bearing species play important roles in acetic acid formation. Ground-based interferometric observations are severely affected by atmospheric conditions. Phase correction is a technique to obtain high quality data and achieve great scientific goals. For our acetic acid survey, a better phase correction technique can not only detect weaker transitions of large molecules, but also increase the map resolution of hot cores. Water vapor radiometers (WVRs) are designed to improve the technique by observing tropospheric water vapor along the lines of sight of interferometers. We have numerically demonstrated the importance of phase correction for interferometric observations and examined the water vapor phase correction technique. Furthermore, we have built two WVR prototypes with new calibration, thermal regulation and backend systems. The WVR prototypes had been tested in a laboratory, on a roof and at the CARMA site to verify their performance. We conclude the WVR thermal stability and dynamic range are critical while the enormous and rapid fluctuations of the sky background emission overwhelm the WVR dynamic range and degrade the WVR sensitivity.

Shiao, Yu-Shao

2008-08-01

338

Interaction of water vapor with polycrystalline UO_2  

NASA Astrophysics Data System (ADS)

We have studied the adsorption and desorption of water vapor (D_2O) on polycrystalline stoichiometric UO2 and oxygen-deficient UO2 surfaces, over the temperature range 100 K to 600 K, using XPS (X-ray photoelectron spectroscopy) and TPD (temperature programmed desorption) under UHV conditions. On the stoichiometric defect-free UO2 surface, water adsorbs and desorbs in molecular form. Sputtering with 1.5 keV Ar ions creates oxygen vacancies (defects) and reduces the near-surface region of the sample, as evidenced by changes in O 1s and U 4f features. Water adsorbs dissociatively on the defective surface with formation of OH species. Heating of the defective surface with a preadsorbed water monolayer causes desorption of molecular D_2. The oxygen remains and restores the sample surface to its initial stoichiometric state. The healing of sub-surface defects occurs through thermal diffusion of atoms from the sample bulk at the temperatures 500-600 K.

Yakshinskiy, B. V.; Schlereth, T.; Madey, T. E.

2004-03-01

339

The First Year of AIM SOFIE Water Vapor in the Polar Mesosphere: Comparisons With HALOE and Model Expectations  

NASA Astrophysics Data System (ADS)

Observations of mesospheric water vapor along with PMC properties by the SOFIE experiment on the AIM spacecraft have provided a means to quantify in detail the water/ice budget in the formation and evolution of PMCs. We will give an overview of the SOFIE water vapor measurements from the first year of the AIM mission, which encompasses one northern and one southern PMC season. These initial results from SOFIE confirm an enhancement of water vapor within the PMC layer that develops simultaneously with the PMC layer as in HALOE data, but there are several apparent differences between SOFIE water measurements and that expected based upon a 12 year climatological average of HALOE measurements. Differences of the layer s peak value and thickness, as seen in HALOE and SOFIE, persist throughout the PMC season. In monthly averages where the HALOE peak values typically exceeds 10 ppmv and occasionally reaches 13 ppmv during July and August, the SOFIE water rarely exceeds 8 ppmv. However, some of these differences are likely due to different SOFIE and HALOE observational sampling, signal to noise, and vertical resolution. Also, the SOFIE water measurement is insensitive to ice spectra. We will discuss these differences and current SOFIE water vapor validation efforts.

Summers, M. E.; Gordley, L. L.; Hervig, M. E.; Randall, C. E.; Rong, P.; Russell, J. M.; Siskind, D. E.; Stevens, M. H.

2008-05-01

340

A Comparison of Columnar Water Vapor Retrievals Obtained with Near-IR Solar Radiometer and Microwave Radiometer Measurements.  

NASA Astrophysics Data System (ADS)

A simple two-channel solar radiometer and analysis technique have been developed for setting atmospheric water vapor via differential solar transmission measurements in and adjacent to the 940-nm water vapor absorption band. A prototype solar radiometer developed for the National Oceanic and Atmospheric Administration (NOAA)/Environmental Research Laboratory underwent trial measurements near Boulder, Colorado, and during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment Phase II cirrus intensive field observation program (Coffeyville, Kansas). These measurements provided the convenient opportunity to compare solar radiometer water vapor retrievals with those obtained using NOAA microwave radiometers. The solar radiometer and microwave radiometer retrievals were found to agree to within 0.1 cm most of the time and to within 0.05 cm the majority of the time, yielding a percent difference in the retrievals generally within 10%. Radiosonde soundings, when available, were also found to generally agree with the microwave and solar radiometer retrievals within 0.1 cm.

Reagan, J.; Thome, K.; Herman, B.; Stone, R.; Deluisi, J.; Snider, J.

1995-06-01

341

Geographic Effects on Precipitation, Water Vapor and Temperature  

NSDL National Science Digital Library

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

342

Clear air turbulence: detection by infrared observations of water vapor.  

PubMed

"Forward-looking" infrared measurements of water vapor from the C-141A Kuiper Airborne Observatory of the National Aeronautics and Space Administration Ames Research Center show large, distinctly identifiable, signal anomalies from 4 to 10 minutes in advance of subsequent encounters with clear air turbulence (CAT). These anomalies are characteristically different from the signals not followed by CAT encounters. Results of airborne field trials in which the infrared radiometer was used indicate that, out of 51 situations, 80 percent were CAT alerts followed by CAT encounters, 12 percent were "false alarms" (CAT alerts not followed by CAT encounters), and 8 percent were CAT encounters not preceded by an infrared signal anomaly or CAT alert. PMID:17778548

Kuhn, P; Caracena, F; Gillespie, C M

1977-06-01

343

Vapor Pressure of HCl - Water and Salt - HCl - Water Solutions Below OC.  

National Technical Information Service (NTIS)

Liquid solution analyses were completed. The complete vapor-liquid equilibria data are tabulated for hydrochloric acid solutions ranging in molality from 5.0 to 15.7, saturated with CaCl2 at nominal temperatures ranging from 0 to -40C. The CaCl2-HCl-water...

E. Miller

1984-01-01

344

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

NASA Astrophysics Data System (ADS)

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

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

2006-03-01

345

Projected regime shift in Arctic cloud and water vapor feedbacks  

NASA Astrophysics Data System (ADS)

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 (Ts), 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 Ts that produces an increase in WV, which in turn increases the downward longwave flux (DLF) and Ts, leading to further evaporation. Another associates the expected increases in cloud cover and optical thickness with increasing DLF and Ts. 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.

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

2011-10-01

346

Fuel and water vaporizer for internal combustion engines  

Microsoft Academic Search

In combination with a gasoline-powered internal combustion engine, and fuel supply, an apparatus is described for injecting a fuel mixture of vaporized fuel, fuel, steam and air into the engine carburetor which consists of: heated means for vaporizing fuel comprising: a closed chamber having a fuel inlet, a vapor outlet, a perforated septum lying horizontally across the lower half of

1986-01-01

347

The Vapor Pressure of HCl - Water Solutions Below 0C.  

National Technical Information Service (NTIS)

An experimental study has been initiated to measure the equilibrium vapor pressure of solutions of hydrochloric acid at temperatures from 0 to -55C. Total vapor pressure data and calculated heat of vaporization values are reported for 19.9 wt pct and 36.0...

E. Miller

1978-01-01

348

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

Microsoft Academic Search

Building on previously published details of the laboratory calibrations of the Harvard Lyman-alpha 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

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

2009-01-01

349

A comparative study of mesospheric water vapor measurements from the ground-based water vapor millimeter-wave spectrometer and space-based instruments  

Microsoft Academic Search

We compare water vapor measurements from the Naval Research Laboratory ground-based Water Vapor Millimeter-wave Spectrometer (WVMS) instruments with measurements taken by five space-based instruments. For coincident measurements the retrievals from all of the instruments show qualitatively similar altitude profiles. The retrieved mixing ratios from most instruments generally differ from an average calculated using retrievals from all of the instruments by

Gerald E. Nedoluha; Richard M. Bevilacqua; R. Michael Gomez; William B. Waltman; Brian C. Hicks; D. L. Thacker; James M. Russell; Mark Abrams; Hugh C. Pumphrey; Brian J. Connor

1997-01-01

350

In search of water vapor on Jupiter: Laboratory measurements of the microwave properties of water vapor and simulations of Jupiter's microwave emission in support of the Juno Mission  

Microsoft Academic Search

This research has involved the conduct of a series of laboratory measurements of the centimeter-wavelength opacity of water vapor along with the development of a hybrid radiative transfer ray-tracing simulator for the atmosphere of Jupiter which employs a model for water vapor opacity derived from the measurements. For this study an existing Georgia Tech high-sensitivity microwave measurement system (Hanley and

Bryan Mills Karpowicz

2010-01-01

351

A qualitative analysis of the effects of water vapor on multi-component vapor-phase carbon adsorption  

SciTech Connect

The effects of water vapor on binary vapor adsorption of toluene and methylene chloride by activated carbon were investigated on a bench-scale experimental system. Three levels of relative humidity (15, 65 and 90 percent) in conjunction with different concentrations of individual adsorbates (from 400 to 1200 ppmv) were tested by tracing the breakthrough curves of each adsorbate eluted from a fixed-bed adsorber. The adsorption capacities of the activated carbon tested for each adsorbate under the various conditions were obtained from calculations based on area integration of the breakthrough curves. It was found that with increasing relative humidity, the shape of breakthrough curves was asymmetrically distorted and the width of the breakthrough curves was broadened for toluene and steepened for methylene chloride. The adsorption capacities for both toluene and methylene chloride were decreased with the increase of relative humidity. The magnitude of the effect of water vapor is greater at the lower toluene concentration and at the higher concentration of methylene chloride. The mechanisms of water vapor influence on the process of multicomponent vapor adsorption are discussed. 12 refs., 9 figs., 1 tab.

Gong, R.; Keener, T.C. [Univ. of Cincinnati, OH (United States)

1993-06-01

352

Reaction of water vapor and oxygen with liquid uranium  

SciTech Connect

The reactions of water vapor and oxygen with liquid uranium were studied by modulated molecular-beam mass spectrometric methods. Equivalent pressures of the reactant fluxes on the surface ranged from 6 x 10/sup -6/ to 2 x 10/sup -4/ torr. Temperatures up to 1570 K were investigated. The metal surface was kept clean during reaction by mechanical removal of the oxide formed with a tungsten needle. For the clean liquid uranium surface, a water reaction probability of approx. 0.4 was deduced both from measurement of the reaction-product hydrogen signal and by the temperature dependence of the scattered reactant signal. Based solely on the latter measure, a reaction probability of 0.6 was estimated for oxygen. The reaction probabilities on the clean surface were temperature-independent. They decreased as the coverage of the surface by islands of oxide increased and, for water, appeared to approach a value of 0.08 for a surface completely covered with an oxide estimated to be 500 A thick. Bombardment of the surface during reaction with argon ions produced an increase in the reactivity on solid uranium but had a negligible effect on the reaction probability for the liquid.

Balooch, M.; Orlander, D.R.; Siekhaus, W.J.

1987-10-01

353

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

NASA Astrophysics Data System (ADS)

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

Kashiwagi, Takao; Kurosaki, Yasuo; Nikai, Isao

354

Liquid-vapor equilibrium isotopic fractionation of water: How well can classical water models predict it?  

Microsoft Academic Search

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, and the Gaussian charge polarizable models. The predicted temperature dependence of the liquid-vapor equilibrium isotopic fractionation factors for H218O\\/H216O, H217O\\/H216O, and 2H1H16O\\/1H216O are compared against the most

Ariel A. Chialvo; Juske Horita

2009-01-01

355

SEASONAL INTERACTIONS BETWEEN CARBON DIOXIDE AND WATER VAPOR FLUX IN CORN CANOPIES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Transpiration of water vapor from plant leavers into the atmosphere is critical for cooling leaves. Water vapor transfer to the atmosphere occurs through the stomata and these pores provide for the entry of carbon dioxide into the leaf. Until recent advances in measurement methods it has been impo...

356

Comparison of Tropospheric Emission Spectrometer nadir water vapor retrievals with in situ measurements  

Microsoft Academic Search

Comparisons of Tropospheric Emission Spectrometer (TES) water vapor retrievals with in situ measurements are presented. Global comparisons of TES water vapor retrievals with nighttime National Centers for Environmental Prediction RS90\\/RS92 radiosondes show a small (<5%) moist bias in TES retrievals in the lower troposphere (standard deviation of ~20%), increasing to a maximum of ~15% bias (with standard deviation reaching ~40%)

Mark W. Shephard; Robert L. Herman; Brendan M. Fisher; Karen E. Cady-Pereira; Shepard A. Clough; Vivienne H. Payne; David N. Whiteman; Joseph P. Comer; Holger Vömel; Larry M. Miloshevich; Ricardo Forno; Mariana Adam; Gregory B. Osterman; Annmarie Eldering; John R. Worden; Linda R. Brown; Helen M. Worden; Susan S. Kulawik; David M. Rider; Aaron Goldman; Reinhard Beer; Kevin W. Bowman; Clive D. Rodgers; Mingzhao Luo; Curtis P. Rinsland; Michael Lampel; Michael R. Gunson

2008-01-01

357

Comparison of Tropospheric Emission Spectrometer nadir water vapor retrievals with in situ measurements  

Microsoft Academic Search

Comparisons of Tropospheric Emission Spectrometer (TES) water vapor retrievals with in situ measurements are presented. Global comparisons of TES water vapor retrievals with nighttime National Centers for Environmental Prediction RS90\\/RS92 radiosondes show a small (<5%) moist bias in TES retrievals in the lower troposphere (standard deviation of ?20%), increasing to a maximum of ?15% bias (with standard deviation reaching ?40%)

Mark W. Shephard; Robert L. Herman; Brendan M. Fisher; Karen E. Cady-Pereira; Shepard A. Clough; Vivienne H. Payne; David N. Whiteman; Joseph P. Comer; Holger Vömel; Larry M. Miloshevich; Ricardo Forno; Mariana Adam; Gregory B. Osterman; Annmarie Eldering; John R. Worden; Linda R. Brown; Helen M. Worden; Susan S. Kulawik; David M. Rider; Aaron Goldman; Reinhard Beer; Kevin W. Bowman; Clive D. Rodgers; Mingzhao Luo; Curtis P. Rinsland; Michael Lampel; Michael R. Gunson

2008-01-01

358

Water Vapor Feedback in the Tropical Upper Troposphere: Model Results and Observations  

Microsoft Academic Search

The sensitivity of water vapor in the tropical upper troposphere to changes in surface temperature is examined using a single-column, radiative convective model that includes couplings between the moistening effects of convective detrainment, the drying effects from clear-air subsidence, and radiative heating and cooling from water vapor. Equilibrium states of this model show that as the surface warms, changes in

Ken Minschwaner; Andrew E. Dessler

2004-01-01

359

WATER VAPOR s-t DIAGRAM FOR TEMPERATURE RANGE FROM -20 TO +40 °C  

Microsoft Academic Search

The paper presents formulas and algorithm for composition of water vapor s-t-diagram for temperature (t) range from -20 to +40 °C. The algorithm may be used by everybody interested in analyzing humid air thermodynamical properties at low and moderate temperatures and energy transformations connected with transition of water vapor. A spreadsheet that is capable of creating output data in the

Valfrid Treier; Veli Palge

360

Mixed water vapor\\/gas transport through the rubbery polymer PEBAX ® 1074  

Microsoft Academic Search

This work investigates the transport behavior of a hydrophilic, highly permeable type of poly ethylene oxide (PEO)-based block copolymer (PEBAX® 1074) as membrane material for the removal of water vapor from light gases. Water vapor sorption isotherms in PEBAX® 1074 represent Flory–Huggins type of sorption and the highly hydrophilic nature of the block copolymer results in high amounts of absorbed

Jens Potreck; Kitty Nijmeijer; Thomas Kosinski; Matthias Wessling

2009-01-01

361

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

Microsoft Academic Search

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

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

2010-01-01

362

Observations of the upper tropospheric and lower stratospheric water vapor with JEM\\/SMILES  

Microsoft Academic Search

Water vapor in the upper troposphere and lower stratosphere (UT\\/LS) plays a significant role in determining the weather and climate on Earth. The tropospheric water vapor acts as a dominant greenhouse gas by intensively absorbing the infrared radiation from the lower atmosphere, while its long wave emissions contribute to cooling in the stratosphere. Despite its high importance, we are still

Hideo Sagawa; Yasuko Kasai; Philippe Baron; Jana Mendrok; Satoshi Ochiai; William G. Read; Nathaniel Livesey

2010-01-01

363

Sensitive coating for water vapors detection based on thermally sputtered calcein thin films  

Microsoft Academic Search

In this paper the adsorption properties of thermally sputtered calcein thin films towards water and other polar molecules vapors are studied by different characterization techniques: quartz crystal microbalance, surface plasmon resonance and visible spectroscopy. Sensitivity of calcein thin films to water vapors resulted much higher as compared with those of a number of dyes whose structure was close to that

I. Kruglenko; Yu. Shirshov; J. Burlachenko; A. Savchenko; S. Kravchenko; M. G. Manera; R. Rella

2010-01-01

364

Water vapor delivery for CIGSe and other thin film vacuum processes  

Microsoft Academic Search

Water vapor has been shown to have significant effect on thin film layers in ALD, MOCVD, and sputtering processes. Such processes are commonly used to generate TCO layers and modify crystal structures via grain size or defect repair. The ability to deliver water vapor free from atmospheric contaminants is critical to film integrity. A novel method for control and delivery

J. Spiegelman; S. Boumsellek

2010-01-01

365

Comparison of MM5 integrated water vapor with microwave radiometer, GPS, and radiosonde measurements  

Microsoft Academic Search

A large dataset of concurrent integrated precipitable water vapor (IPWV) estimates from ground-based microwave radiometers (MWRs), global positioning system (GPS) ground-receivers, and radiosonde observations (RAOBs) has been collected in five different sites in Central Italy. Both MWRs and GPS have shown a capability of accurate and continuous water vapor monitoring. These data are used to study the seasonal and spatial

Adelaide Memmo; Ermanno Fionda; Tiziana Paolucci; Domenico Cimini; Rossella Ferretti; Stefania Bonafoni; Piero Ciotti

2005-01-01

366

Study of the reaction of water vapors with carbon fibers by an adsorption-calorimetric method  

Microsoft Academic Search

The isotherms and differential heats of adsorption of water vapor on two samples of activated carbon fiber material (CFM) have been measured. The adsorption of water vapor on CFM has been found to take place virtually over the entire range of surface occupation with thermal effects lower than the heat of condensation. The appearance of endothermic thermal effects on the

I. G. Polyakova; Yu. I. Tarasevich; V. E. Polyakov

1994-01-01

367

Simulation of surface structural relaxation kinetics in silica glass accelerated by water vapor  

Microsoft Academic Search

It is known that surface structural relaxation of silica glass takes place more rapidly than bulk structural relaxation, especially in the presence of water vapor. The effect of water vapor pressure, heat-treatment temperature and initial fictive temperature on the surface structural relaxation kinetics in silica glasses was investigated by measuring the change of the surface fictive temperature determined from the

A. Koike; M. Tomozawa

2008-01-01

368

Pointed water vapor radiometer corrections for accurate Global Positioning System surveying  

Microsoft Academic Search

Delay of the Global Positioning System (GPS) signal due to atmospheric water vapor is a major source of error in GPS surveying. Improved vertical accuracy is important for sea level and polar isostasy measurements, geodesy, normal fault motion, subsidence, earthquake studies, air and ground-based gravimetry, ice dynamics, and volcanology. We conducted a GPS survey using water vapor radiometers (WVRs) pointed

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

1993-01-01

369

Remote Sensing of Atmospheric Water Vapor Variation with GPS: On the case of Typhoon EWINIAR  

Microsoft Academic Search

The Global Positioning System (GPS) provides a relatively inexpensive method to remotely sense atmospheric water vapor in all weather conditions. We apply the GPS Meteorology technique to monitor Precipitable Water Vapor (PWV) Variation during the progress of Typhoon EWINIAR. Typhoon EWINIAR, which caused serious damage, was passed over in Korea peninsula during 8 July to 11 July, 2006. We estimated

Dong-Seob Song; Hong-Sic Yun; Woon-Chul Jung; Ji-Hoon Kang

370

Characterization of oxide films generated on stainless steel in water vapor and oxygen plasmas  

Microsoft Academic Search

The plasma oxidation of stainless steel was studied using plasmas of water vapor and oxygen. The films generated on the stainless steel were analyzed by a range of surface analysis methods such as SIMS, XRD, Raman, and AES, and the structure and composition of oxide films were determined. The oxide films generated in water vapor plasma and oxygen plasma were

Tatsuya Suzuki; Yukiko Sawado; Yasuhiko Fujii

2005-01-01

371

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

Microsoft Academic Search

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

Yansheng Ma; Bo Liu

2009-01-01

372

Water Vapor Permeation of Metal Oxide\\/Polymer Coated Plastic Films  

Microsoft Academic Search

Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how

Yukihiro Numata; Toshiyuki Oya; Mitsuru Kuwahara; Katsuya Ito

2010-01-01

373

Nitrogen oxide, water vapor, noctilucent clouds, and radio wave emission and absorption near the mesopause  

Microsoft Academic Search

The paper deals with new methods of detecting nitrogen oxide and water vapor near the mesopause from its emissions. It is shown that changes in water vapor concentration are primarily responsible for ionospheric absorption variations in the D region that are not associated with chromospheric flares and entries of ionizing particles.

V. I. Krasovskii; Z. Ts. Rapoport; A. I. Semenov; V. G. Sobolev; N. N. Shefov

1980-01-01

374

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

Microsoft Academic Search

An important source of error in very-long-baseline interferometry (VLBI) estimates of baseline length is unmodeled variations of the refractivity of the neutral atmosphere along the propagation path of the radio signals. The authors present and discuss the method of using data from a water vapor readiometer (WVR) to correct for the propagation delay caused by atmospheric water vapor, the major

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

1991-01-01

375

Search for Episodic Increases in Upper Atmospheric Water Vapor as Evidence of an Extraterrestrial Source.  

National Technical Information Service (NTIS)

This study examines the short-term variability of upper atmospheric water vapor with the intent of examining a proposed extraterrestrial water vapor source. This source would be provided by an influx of the small (12 m in. diameter) comets described by Fr...

M. F. Bonadonna

1990-01-01

376

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

Microsoft Academic Search

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

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

377

Selection of Process Parameters for Sodium Removal via the Water Vapor Nitrogen Process.  

National Technical Information Service (NTIS)

This report reviews the water vapor nitrogen (WVN) process for removing sodium from stainless steel equipment, with emphasis on the basis for selecting final operating parameters. the process includes vapor treatment with 5% water at 160 F to 190 F, hot w...

M. Crippe

1977-01-01

378

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

Microsoft Academic Search

Tropospheric water vapor plays a key role in the prediction of convective storm initiation, precipitation and extreme weather events. Conventionally, water vapor profiles are derived from dewpoint and temperature measurements using instrumented weather balloons, including radiosondes. These balloons take approximately one hour to measure from surface to tropopause, and transmitter-sensor packages cannot be reused. Such in-situ measurements provide profiles with

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

2006-01-01

379

Recent Changes in Tropospheric Water Vapor over the Arctic  

NASA Astrophysics Data System (ADS)

Changes in tropospheric water vapor over the Arctic are examined for the period 1979 to 2008 using monthly mean humidity and temperature data from six different atmospheric reanalyses (CFSR, MERRA, NCEP-1, JRA-25, ERA-40, ERA-Interim) and from nine high latitude stations north of 70°N contained in a homogenized version of the Integrated Global Rawinsonde Archive. A major deficiency in all of the reanalyses is excessive humidity below about 850 hPa, linked in part to inability of the reanalyses to adequately represent the low-level Arctic temperature inversion. Most of the rawinsonde stations show upward trends in column-integrated (surface to 500 hPa) water vapor (precipitable water). However, these trends and their statistical significance vary greatly depending on the station and month. Seasonal patterns can be seen with trends generally strongest during summer. The two most modern reanalyses, MERRA and CFSR, show increasing surface-500 hPa precipitable water over the analysis period averaged for the region north of 70°N. Positive anomalies dominate the most recent decade (2000-2008) in all seasons, strongest in late summer and autumn over the northern North Atlantic, including the Greenland, Norwegian and Barents seas, and in the Beaufort and Chukchi seas on the Pacific side of the Arctic. This pattern is linked to positive anomalies in air and sea surface temperature and negative anomalies in end-of-summer sea ice extent. Recent increases in specific humidity extend to about the 700 hPa. However, changes depicted in MERRA and CFSR depart greatly from those in JRA-25 and NCEP-1, neither of which show any clear trends. Changes depicted in ERA-40 over the available period of record (1979-2002) are most similar to those in MERRA and CFSR. Differences between the reanalyses and between the reanalyses and rawinsonde profiles in part reflect issues of satellite data assimilation; fields from both CSFR and MERRA appear to be strongly affected by introduction of the AIRS sensor.

Barrett, A. P.; Serreze, M. C.; Stroeve, J. C.

2011-12-01

380

Stratospheric water vapor measurements during CHEOPS-3. [CHemistry of Ozone in the Polar Stratosphere  

SciTech Connect

During January 1990, in situ stratospheric water vapor measurements were performed over the Arctic during the CHEOPS experiment at Kiruna. The instrument used is a balloon-borne frost-point hygrometer. Results of two flights are shown: one of the flights showed thermal structure indicative of cooling induced by orographic forcing and favorable to PSC formation. Mixing ratio were the same for the two flights, 4-5 ppmv between 12 and 22 km. However, above 22 km, an increase in mixing ratio to 7.5 ppmv is observed. Because this increase is much higher than at mid-latitudes, the authors examine it in detail.

Ovarlez, J. (Ecole Polytechnique, 91, Palaiseau (France))

1991-04-01

381

Comparison of ground-based and Viking Orbiter measurements of Martian water vapor - Variability of the seasonal cycle  

Microsoft Academic Search

Earth-based observations of Mars atmospheric water vapor are presented for the 1975-1976, 1977-1978, and 1983 apparitions. Comparisons are made with near-simultaneous spacecraft measurements made from the Viking Orbiter Mars Atmospheric Water Detection experiment during 1976-1978 and with previous earth-based measurements. Differences occur between the behavior in the different years, and may be related to the Mars climate. Measurements during the

B. M. Jakosky; E. S. Barker

1984-01-01

382

Atmospheric water vapor and geoid measurements in the open ocean with GPS  

NASA Astrophysics Data System (ADS)

We have conducted two experiments to determine precipitable water vapor (PWV) and sea surface heights from a cruising ship in the open ocean. During the first experiment (July 7-13, 02) GPS and radiosonde PWV agreed at the 2 mm rms level. During the second experiment (Aug 23-30, 03) GPS compared at 1.5 mm rms (1.1 mm GPS high bias) with eight ship-launched radiosondes and at 2.8 mm rms (1.2 mm GPS high bias) to a ship-based water vapor radiometer (WVR). We estimate that the vertical position of the GPS antenna in the open ocean was determined to better than 10 cm rms. After correcting for ocean tides GPS estimated sea surface heights from the second cruise compared to the CARIB97 geoid at the 32 cm level in the vertical. Because space based observations of PWV over the oceans generally require cloudless conditions and are accurate to about 5-10% we conclude that ship based GPS observations can provide additional useful meteorological information. Based on the 10-cm vertical position rms and the high horizontal resolution of ship-based positions we further conclude that useful geodetic information can be obtained from high accuracy GPS observations from ships in the open oceans.

Rocken, Christian; Johnson, James; Van Hove, Teresa; Iwabuchi, Tetsuya

2005-06-01

383

22 GHz Water Vapor Radiometry at the VLA  

NASA Astrophysics Data System (ADS)

As part of the VLA Upgrade Project (Bastian & Bridle 1995), new low-noise, high-efficiency K-band (18-26 GHz) receiver systems are being constructed and placed on the antennas of the VLA. Water vapor radiometry (WVR) systems have been designed to be placed alongside these new receivers, in order to attempt to measure and correct for atmospheric phase fluctuations at the higher frequencies of operation of the VLA. These WVR systems are similar to Dave Woody's in design (Marvel & Woody 1998), with minor modifications. The radiation is received through the astronomy receiver in its dewar, then filtered into 3 channels. The intent is to provide the data measured by the WVRs along with the visibility data to post-processing software (AIPS or aips++) in order to correct for atmospheric phase fluctuations in the visibilities. I will present several issues related to WVR at the VLA, including center frequency and width of the WVR channels, effects of liquid water on phase retrieval, and divergence of WVR beam from astronomical receiver beam in the atmosphere.

Butler, B. J.

384

Measurements of water vapor adsorption on the Geysers rocks  

SciTech Connect

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

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

1996-01-24

385

Interactions among Cloud, Water Vapor, Radiation, and Large-Scale Circulation in the Tropical Climate. Part I: Sensitivity to Uniform Sea Surface Temperature Changes  

Microsoft Academic Search

The responses of tropical clouds and water vapor to SST variations are investigated with simple numerical experiments. The fifth-generation Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model is used with doubly periodic boundary conditions and a uniform constant sea surface temperature (SST). The SST is varied and the equilibrium statistics of cloud properties, water vapor, and circulation at

Kristin Larson; Dennis L. Hartmann

2003-01-01

386

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

SciTech Connect

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.

Pazmany, Andrew

2006-11-09

387

LASE Measurements of Water Vapor, Aerosol, and Cloud Distributions in Regions of African Easterly Waves and Saharan Dust Layers  

NASA Astrophysics Data System (ADS)

LASE (Lidar Atmospheric Sensing Experiment) measured 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. Measurements were made in conjunction with African Easterly Waves (AEW), Tropical Disturbances (TDs), and Saharan Aerosol Layers (SALs); and in clear air and convective regions. Interactions of Saharan dust layers with tropical air during early stages of the development of TDs were observed. LASE measurements were used to profile the dust layers and guide in situ aircraft sampling. The dust layers over the ocean and the continent were found to range in altitude from near surface to 6 km. Aerosol scattering ratios at 817 nm ranged from 0 to >20, and their optical thickness ranged from 0 to >1. Highly attenuating (cloud) regions with high (~100%) RH were occasionally observed within the dust layers. Dust layers were situated generally north of the TDs, however, dust layers were also observed in and around the TDs. A wide range of water vapor concentrations were observed in and around the TDs, and in general, the dust layers were anti-correlated with the water vapor distributions. LASE water vapor, aerosol, cloud measurements during NAMMA provided an opportunity to compare with in situ aircraft, dropsonde, and radiosonde measurements; and satellite observations. Examples of LASE measurements along with their relationship with the AEWs, at various stages of their development, will be presented in this paper.

Ismail, S.; Browell, E. V.; Ferrare, R. A.; Notari, A.; Kooi, S. A.; Butler, C. F.; Anderson, B. E.; Heymsfield, G. M.; Schmidlin, F. J.

2007-05-01

388

General Requirements and Recommendations for Vapor Nucleation Rate Experiments  

Microsoft Academic Search

Agreement between experimentally measured vapor nucleation rates and current theoretical predictions exists for only a limited number of systems. These inconsistencies can result from differences in measurement methods and assumptions used to interpret the experimental results. Usually the causes of these disagreements are unclear. The current state of the art is such that experimental results using different methods can lead

M. P. Anisimov; P. K. Hopke; A. S. Berezina

2003-01-01

389

Experimental investigation on heat transfer of forced convection condensation of ethanol-water vapor mixtures on a vertical mini-tube  

NASA Astrophysics Data System (ADS)

In this paper, condensation heat transfer characteristics of ethanol-water vapor mixtures on a vertical mini-vertical tube with 1.221 mm outside diameter were investigated experimentally. The experiments were performed at different velocities and pressures over a wide range of ethanol mass fractions in vapor. The test results indicated that, with respect to the change of the vapor-to-surface temperature difference, the condensation curves of the heat transfer coefficients revealed nonlinear characteristics, and had peak values. At 2 % ethanol mass fraction in vapor, the condensation heat transfer coefficient value of the ethanol-water vapor mixture was found to have a maximum heat transfer coefficient of 50 kW m-2 K-1, which was 3-4 times than that of pure steam. The condensation heat transfer coefficients decreased with increased ethanol mass fraction in vapor. The vapor pressure and vapor velocity had a positive effect on the condensation heat transfer coefficients of ethanol-water vapor mixtures.

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

2013-09-01

390

Dynamic characteristics of laser-induced vapor bubble formation in water based on high speed camera  

NASA Astrophysics Data System (ADS)

In clinical practice, laser ablation usually works under liquid environment such as water, blood or their mixture. Laser-induced vapor bubble or bubble formation and its consequent dynamics were believed to have important influence on tissue ablation. In the paper, the dynamic process of vapor bubble formation and consequently collapse induced by pulsed Ho:YAG laser in static water was investigated by using high-speed camera. The results showed that vapor channel / bubble can be produced with pulsed Ho:YAG laser, and the whole dynamic process of vapor bubble formation, pulsation and consequently collapse can be monitored by using high-speed camera. The dynamic characteristics of vapor bubble, such as pulsation period, the maximum depth and width were determined. The dependence of above dynamic parameters on incident radiant exposure was also presented. Based on which, the influence of vapor bubble on hard tissue ablation was discussed.

Zhang, Xian-zeng; Guo, Wenqing; Zhan, Zhenlin; Xie, Shusen

2013-08-01

391

INFLUENCE OF ICE SURFACE EMISSIVITYVARIATIONS ON THE ACCURACY OF WATER VAPOR RETRIEVAL IN POLAR REGIONS USINGAMSU-B CHANNELS  

Microsoft Academic Search

Atmospheric water vapor is essential in meteorological and environmental studies. Till now, integrated water vapor content retrieval can only be operational done over oceans from microwave sensor measurements. Over land water vapor retrieval scheme is still explored. In 1998, J. Miao proposed a method to retrieve the integrated water vapor (IWV) using SSM\\/T2 and AMSU-B channels over the ice covered

Mu Qiao; Jungang Miao

392

Water vapor and air transport through ponds with floating aquatic plants.  

PubMed

The purpose of this paper is to estimate the evaporation rate in the purification of wastewater by aquatic plants with aeration. Evaporation of surface water is important in dewatering processes. In particular, this is true in arid climates, where evaporation rates are high. Aeration is known to enhance the wastewater purification process, but it increases concurrently the water evaporation rates. Evaporation and evapotranspiration rates were tested under field and laboratory conditions. Batch experiments were performed to study the levels of evaporation and evapotranspiration in free-water-surface, aquatic-plant systems. The experiments verified that, in these systems, the rate of evaporation increased as a result of aeration in the presence and absence of the aquatic plants. The evaporation rates resulting from aeration were found to be significant in the water balance governing the purification process. A preliminary model for description of the effect of rising air bubbles on the transport of water vapors was formulated. It is shown that aeration may account for a significant part of water losses that include surface evaporation. PMID:17059143

Kirzhner, F; Zimmels, Y

2006-08-01

393

The application of the high-speed photography in the experiments of boiling liquid expanding vapor explosions  

NASA Astrophysics Data System (ADS)

The liquefied-petroleum gas tank in some failure situations may release its contents, and then a series of hazards with different degrees of severity may occur. The most dangerous accident is the boiling liquid expanding vapor explosion (BLEVE). In this paper, a small-scale experiment was established to experimentally investigate the possible processes that could lead to a BLEVE. As there is some danger in using LPG in the experiments, water was used as the test fluid. The change of pressure and temperature was measured during the experiment. The ejection of the vapor and the sequent two-phase flow were recorded by a high-speed video camera. It was observed that two pressure peaks result after the pressure is released. The vapor was first ejected at a high speed; there was a sudden pressure drop which made the liquid superheated. The superheated liquid then boiled violently causing the liquid contents to swell, and also, the vapor pressure in the tank increased rapidly. The second pressure peak was possibly due to the swell of this two-phase flow which was likely to violently impact the wall of the tank with high speed. The whole evolution of the two-phase flow was recorded through photos captured by the high-speed video camera, and the "two step" BLEVE process was confirmed.

Chen, Sining; Sun, Jinhua; Chen, Dongliang

2007-01-01

394

An evaluation of the SAGE III Version 4 aerosol extinction coefficient and water vapor data products  

NASA Astrophysics Data System (ADS)

Herein, we provide an assessment of the data quality of Stratospheric Aerosol and Gas Experiment (SAGE III) Version 4 aerosol extinction coefficient and water vapor data products. The evaluation is based on comparisons with data from four instruments: SAGE II, the Polar Ozone and Aerosol Measurement (POAM III), the Halogen Occultation Experiment (HALOE), and the Microwave Limb Sounder (MLS). Since only about half of the SAGE III channels have a direct comparison with measurements by other instruments, we have employed some empirical techniques to evaluate measurements at some wavelengths. We find that the aerosol extinction coefficient measurements at 449, 520, 755, 869, and 1021 nm are reliable with accuracies and precisions on the order of 10% in the primary aerosol range of 15 to 25 km. We also believe this to be true of the aerosol measurements at 1545 nm though we cannot exclude some positive bias below 15 km. We recommend use of the 385 nm measurements above 16 km where the accuracy is on par with other aerosol channels. The 601 nm measurement is much noisier (~20%) than other channels and we suggest caution in the use of these data. We believe that the 676 nm data are clearly defective particularly above 20 km (accuracy as poor as 50%) and the precision is also low (~30%). We suggest excluding this channel under most circumstances. The SAGE III Version 4 water vapor data product appears to be high quality and is recommended for science applications in the stratosphere below 45 km. In this altitude range, the mean differences with all four corroborative data sets are no bigger than 15% and often less than 10% with exceptional agreement with POAM III and MLS. Above 45 km, it seems likely that SAGE III water vapor values are increasingly too large and should be used cautiously or avoided. We believe that SAGE III meets its preflight goal of 15% accuracy and 10% precision between 15 and 45 km. We do not currently recommend limiting the SAGE III water vapor data utility in the stratosphere by aerosol loading.

Thomason, L. W.; Moore, J. R.; Pitts, M. C.; Zawodny, J. M.; Chiou, E.-W.

2009-10-01

395

Water vapor measurements at ALOMAR over a solar cycle compared with model calculations by LIMA  

NASA Astrophysics Data System (ADS)

Microwave water vapor measurements between 40 and 80 km over a solar cycle (1996-2007) were carried out in high latitudes at ALOMAR (69.290 N, 16.030 E), Norway. Some gapes and only few interruptions of monitoring occurred during this period. The observations are marked by a certain year-to-year variability not directly related to the solar activity. In the upper domain in winter the water vapor mixing ratios are anti-correlated to the solar activity whereas in summer minima occurred in the years after the solar maximum in 2000/01. In winter sudden stratospheric warmings modulate the water vapor mixing ratios. Within the stratopause region a middle atmospheric water vapor maximum was observed. It results from the methane oxidation and is a regular feature there. The maximum altitude increases toward summer by approximately 5 km. During this season a secondary water vapor maximum also occurred above 65 km most pronounced in late summer. A strong day-to-day variability connected with planetary wave activity was found over the whole year. Although model calculations by means of the real date model LIMA (Leibniz-Institute Middle Atmosphere model) reflect essential patterns of the water vapor variation the results also show that exchange processes between the stratosphere and troposphere not modeled by LIMA influences the long-term variability. We discuss the chemical and dynamical background of the variation of water vapor in the middle atmosphere.

Sonnemann, Gerd; Hartogh, Paul; Song, Li; Grygalashvyly, Mykhaylo; Berger, Uwe

396

Horizontal water vapor transport in the lower stratosphere from subtropics to high latitudes during boreal summer  

NASA Astrophysics Data System (ADS)

We compare global water vapor observations from Microwave Limb Sounder (MLS) and simulations with the Lagrangian chemical transport model CLaMS (Chemical Lagrangian Model of the Stratosphere) to investigate the pathways of water vapor into the lower stratosphere during Northern Hemisphere (NH) summer. We find good agreement between the simulation and observations, with an effect of the satellite averaging kernel especially at high latitudes. The Asian and American monsoons emerge as regions of particularly high water vapor mixing ratios in the lower stratosphere during boreal summer. In NH midlatitudes and high latitudes, a clear anticorrelation between water vapor and ozone daily tendencies reveals a large region influenced by frequent horizontal transport from low latitudes, extending up to about 450K during summer and fall. Analysis of the zonal mean tracer continuity equation shows that close to the subtropics, this horizontal transport is mainly caused by the residual circulation. In contrast, at higher latitudes, poleward of about 50°N, eddy mixing dominates the horizontal water vapor transport. Model simulations with transport barriers confirm that almost the entire annual cycle of water vapor in NH midlatitudes above about 360K, with maximum mixing ratios during summer and fall, is caused by horizontal transport from low latitudes. In the model, highest water vapor mixing ratios in this region are clearly linked to horizontal transport from the subtropics.

Ploeger, F.; Günther, G.; Konopka, P.; Fueglistaler, S.; Müller, R.; Hoppe, C.; Kunz, A.; Spang, R.; Grooß, J.-U.; Riese, M.

2013-07-01

397

Excursions into the strong precipitation regime; long tails in water vapor and other tracers (Invited)  

NASA Astrophysics Data System (ADS)

From previous work, we know that conditional averages of precipitation undergo rapid transition to a strongly convective regime above a critical value of water vapor for a given temperature. Here we examine two aspects of how one gets into this regime. 1) Temporal relations for the water vapor, for instance preceding a high water vapor/convective state, using Tropical Rainfall Measuring Mission, AQUA, and Atmospheric Radiation Measurement program data. Both synoptic scale and mesoscale increases of water vapor prior to precipitation events are noted. 2) The probability distribution for column integrated water vapor (CWV) has a Gaussian core but an approximately exponential tail under precipitating conditions. Idealized passive tracer forced-advection-diffusion problems can produce such distributions---but are simple prototypes relevant to three-dimensional atmospheric transports with complex sources and sinks? And can we trust the tails estimated from retrievals under strongly precipitating conditions? We show that such tails are found in observed, model, and reanalysis data sets for column integrated tracers under a wide set of circumstances, including for important tracers with anthropogenic sources, namely CO and new retrievals of CO2. The long tails in water vapor are associated with vertical transport and can occur independent of a local precipitation sink. In addition to the importance of CO and CO2 distributions in their own right, the multi-tracer comparison boosts confidence in the long tails in the water vapor distribution that lead to relatively frequent excursions into heavy precipitation conditions.

Neelin, J.; Holloway, C. E.; Lintner, B. R.; Tian, B.; Li, Q.; Zhang, L.; Patra, P. K.; Chahine, M. T.; Stechmann, S.

2009-12-01

398

On the Transient Correlation Structure of Water Vapor and Carbon Dioxide Time Series Over Low-Profile Vegetation  

Microsoft Academic Search

Much work has previously centered on temperature and water vapor similarity as a result of its application to the flux-variance method. Less attention, however, has been paid to similarity between carbon dioxide and water vapor. In this study, we analyze water vapor and carbon dioxide time series to infer causes of departure from correlation coefficients of +\\/-1. Photosynthesis and transpiration,

T. M. Scanlon; P. Sahu

2007-01-01

399

On Sensitivity of Spectral Radiative Fluxes to Atmospheric Water Vapor in the 940 nm Region (Numerical Simulation)  

Microsoft Academic Search

Water vapor is well known to be a critical component in many aspects of atmospheric research, such as radiative transfer and cloud and aerosol processes. This requires both improved measurements of the columnar water vapor and its profiles in the atmosphere in a wide range of conditions, and adjustment of water vapor parameterizations in radiation codes including the perfection of

T. B. Zhuravleva; K. M. Firsov

2005-01-01

400

Preliminary Evaluation of Version 6.2 SAGE II Water Vapor Data Set: Comparison With ATMOS\\/ATLAS3 Measurements  

Microsoft Academic Search

Acurate long-term profile measurements of stratospheric water vapor are needed to better understand possible changes that may have occurred over the past 20 years and its effect on the ozone distribution. The SAGE II satellite instrument has been obtaining water vapor measurements of the middle atmosphere since its launch in 1984. Previous versions of the SAGE II water vapor data

E. Chiou; W. P. Chu; L. W. Thomason; S. P. Burton; H. A. Michelsen

2003-01-01

401

The Use of GPS Measurements for Water Vapor Determination.  

NASA Astrophysics Data System (ADS)

A workshop on the use of Global Positioning System (GPS) measurements in weather and climate with emphasis on water vapor determination, was organized by the National Environmental Research Council's (NERC) Environmental Systems Science Centre (ESSC), at the University of Reading, Reading, United Kingdom, and took place there 29-31 August 2001.This paper gives a broad overview and general background of the use of GPS data for weather and climate. It outlines the objectives of the workshop and presents ongoing national, regional, and international activities both for ground-based and satellite-based systems. This includes work in the United States, China, and Japan, and different European efforts, including activities under European Community programs.Data assimilation of GPS data for weather prediction and climate is discussed as are ways in which to develop GPS-based systems to become an integrated part of the World Weather Watch. This includes ways of systematically using GPS data from the international geodetic network for climate monitoring purposes.

Bengtsson, Lennart; Robinson, Gary; Anthes, Rick; Aonashi, Kazumasa; Dodson, Alan; Elgered, Gunnar; Gendt, Gerd; Gurney, Robert; Jietai, Mao; Mitchell, Cathryn; Mlaki, Morrison; Rhodin, Andreas; Silvestrin, Pierluigi; Ware, Randolph; Watson, Robert; Wergen, Werner

2003-09-01

402

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

NASA Astrophysics Data System (ADS)

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. Some possible implications for the formation of stratospheric aerosols are also discussed.

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

1990-07-01

403

Vapor pressures in the ternary system water-nitric acid-sulfuric acid at low temperatures  

SciTech Connect

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 0C. From these results the partial vapor pressures over the ternary system water-nitric acid-sulfuric (liquid or supercooled) have been estimated and compared with the available experimental data of Vandoni at 0C. Some possible implications for the formation of stratospheric aerosols are also discussed.

Jaecker-Voirol, A.; Ponche, J.L.; Mirabel, P. (Universite Louis Pasteur, Strasbourg (France))

1990-07-20

404

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+methyl ethyl ketone (MEK), MEK+isopropyl acetate, acetic acid+MEK+water and acetic acid+MEK+isopropyl acetate+water are measured at 101.33kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in

Qiang Xie; Hui Wan; MingJuan Han; GuoFeng Guan

2009-01-01

405

Dynamics of water-vapor absorption by a quartz fiber lightguide when it is being drawn  

NASA Astrophysics Data System (ADS)

This paper presents data concerning two processes by which a quartz fiber lightguide interacts with water vapor. When a lightguide is fabricated, the moving fiber can adsorb water vapor from the ambient atmosphere, and, after a metallic leak-proof cladding has been formed, a process occurs by which water molecules migrate into the bulk of the quartz glass. The latter is accompanied by an increase of the bending strength of the quartz fiber in time.

Shevandin, V. S.

2006-12-01

406

Simulated Trends of Stratospheric Water Vapor From 1960 to 1999 and Their Impact on Ozone Chemistry  

Microsoft Academic Search

Water vapor is an important controlling factor for climate feedback processes. Therefore, the understanding of the variability and of long-term changes of water vapor concentration in the UT\\/LS is essential for the understanding of the climate system. We applied the coupled chemistry-climate model E39\\/C of the troposphere and lower stratosphere in order to reproduce the main climate interactions involving water

A. Stenke; V. Grewe; M. Dameris; M. Ponater; R. Sausen

2006-01-01

407

Water Transfer from Soil to Seed: The Role of Vapor Transport  

Microsoft Academic Search

sis is that most of the water imbibed by seeds can be supplied as vapor, and therefore it should not be as- Mixed solid-water-gas media such as soil can supply water to a dry sumed that liquid flow through seed-soil contact is the object as both liquid and vapor. Modelers and agricultural engineers have commonly assumed liquid transport dominates imbibition

Stewart B. Wuest

408

FEATURES OF THE WATER VAPOR TRANSPORT AND PRECIPITATION VARIATION OF THE TIBETAN PLATEAU AND ITS SURRDINGS  

Microsoft Academic Search

Climatological features are investigated for large-scale water vapor transport over the Tibetan Plateau and its surroundings based on the vertically integrated water vapor flux from 1980 to 1997.It is found that in winter and spring, the moisture of the region is mainly from the middle-latitude westerly water transport, in summer (July), the moisture comes from the Bay of Bengle and

Changyan Zhou; Yueqing Li; Jun Peng

409

Influence of convective processes on the isotopic composition (?18O and ?D) of precipitation and water vapor in the tropics: 1. Radiative-convective equilibrium and Tropical Ocean–Global Atmosphere–Coupled Ocean-Atmosphere Response Experiment (TOGA-COARE) simulations  

Microsoft Academic Search

Cumulus convection constitutes a key process in the control of tropical precipitation and the vertical transport of atmospheric water. To better understand the influence of convective processes on the isotopic composition of precipitation and water vapor, water stable isotopes (H218O and HDO) are introduced into a single column model including the Emanuel convective parameterization. This paper analyzes unidimensional simulations of

Sandrine Bony; Camille Risi; Françoise Vimeux

2008-01-01

410

Latitudinal survey of middle atmospheric water vapor revealed by shipboard microwave spectroscopy. Master's thesis  

SciTech Connect

Water vapor is one of the most important greenhouse gases and is an important tracer of atmospheric motions in the middle atmosphere. It also plays an important role in the chemistry of the middle atmosphere and through its photodissociation by solar radiation, it is the major source of hydrogen escaping to space. Ground-based microwave measurements conducted in the 1980s have provided a fair understanding of the seasonal variation of mesospheric water vapor in the northern hemisphere mid-latitudes, but the global distribution of water vapor in the middle atmosphere is only beginning to be revealed by space-based measurements.

Schrader, M.L.

1994-05-01

411

Intensive use of biomass feedstock in ethanol conversion: The alcohol-water, vapor-phase separation  

Microsoft Academic Search

Fermentation of ethanol in a system whereby the biomass is used intensively (both to separate alcohol from water by vapor phase adsorption and to serve as the feedstock) is shown to be possible on theoretical grounds when the biomass is grain. The rationale for a vapor-phase adsorption process as an alternative to distillation is shown to be energetically valid above

George H. Robertson; Larry R. Doyle; Attila E. Pavlath

1983-01-01

412

Evidence of true bound and metastable dimers and trimers presence in high temperature water vapor spectra  

NASA Astrophysics Data System (ADS)

We consider the ratio between true bound and metastable states of small water clusters in water vapor. Reanalysis of water vapor spectra recorded at 650 K and pressures up to 110 atm in the O?H fundamental stretching region was performed using an improved spectroscopic model that revealed manifestations of dimers and trimers in both true bound and metastable states. Dimer and trimer quantities in both states were determined in the model by the corresponding equilibrium constants which were variable coefficients in equations of integrated spectral intensity, of absorption coefficient, and of water vapor thermodynamic state. The obtained constants are in good agreement with the previously known values, including agreement with those obtained from the empirical high-precision thermodynamic water vapor data. The analysis confirms that amounts of bound dimers and trimers are significant even at supercritical temperature.

Odintsova, T. A.; Tretyakov, M. Yu.

2013-05-01

413

Study on condensation of a single vapor bubble into subcooled water-Part 2; Experimental analysis  

SciTech Connect

This paper reports experimental analyses performed for the results of flow visualization in which saturated steam bubbles approximately 10 mm in diameter were injected into quiescent subcooled water. The patterns of bubble collapse were analyzed from photographs selected from a motion picture film and presented as the instantaneous bubble diameter vs. time. An upward motion was imparted to the bubbles by buoyancy, and because of heat transfer and condensation at the liquid-vapor interface, the bubbles diminished in size as they ascended. The time variations of the bubble diameter and position were determined from detailed analysis of the photographs. The experiments were performed for pressure levels from atmospheric to 10{sup 6}Pa and for temperature differences between the saturated steam and subcooled water from 10 to 70{degrees}C. From these, the time for bubbler collapse and the average heat transfer coefficient are inferred.

Kamei, S.; Hirata, M. (Faculty of Engineering, Univ. of Tokyo (JP))

1990-01-01

414

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

PubMed

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 (17)O-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

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

2013-06-24

415

Analysis of precipitable water vapor and liquid water path by microwave radiometer during 2001 - 2002  

NASA Astrophysics Data System (ADS)

Based on the observation of the Microwave Radiometer (MWR, WVR-1100) at Cheongju and Hapcheon in South Korea, the precipitable water vapor (PWV) and liquid water path (LWP) have been analyzed. Comparison of the PWVs measured by MWR at Cheongju and Hapcheon gives good agreement above the 0.9 of correlation coefficient with that of radiosonde at the two nearest sites (Osan and Gwangju), respectively. The PWVs show the seasonality, but do not the regional characteristics evidently. The LWP shows not only the seasonality but also regional difference. These regional characteristics seem come from the regional different solar radiation.

Yang, H.; Chang, K.; Lee, S.; Jang, Y.; Choi, Y.

2007-12-01

416

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

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

417

Flash Vaporization of Alcohol-Water Mash. Final Technical Report.  

National Technical Information Service (NTIS)

Original design constraints of flash vaporization of the entire liquid fraction of a fermented mash met with many operational considerations which presented difficulty in obtaining the desired effect. In addition, theoretical parameters within the origina...

J. C. Lustgarten

1984-01-01

418

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

Microsoft Academic Search

The salt effect on the vapor-liquid equilibrium of mixed solvents provides a potential technique of extractive distillation, in which a dissolved salt, rather than a liquid additive, is used as the separating agent. This salt distillation process has been used in the purification of close-boiling, azeotropic, and other systems which are difficult to separate. The isobaric vapor-liquid equilibrium for ethanol

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

1996-01-01

419

Water Vapor in nearby Infrared Galaxies as Probed by Herschel  

NASA Astrophysics Data System (ADS)

We report the first systematic study of the submillimeter water vapor rotational emission lines in infrared (IR) galaxies based on the Fourier Transform Spectrometer (FTS) data of Herschel SPIRE. Among the 176 galaxies with publicly available FTS data, 45 have at least one H2O emission line detected. The H2O line luminosities range from ~1 × 105 L ? to ~5 × 107 L ? while the total IR luminosities (L IR) have a similar spread (~1-300 × 1010 L ?). In addition, emission lines of H2O+ and H_2^{18}O are also detected. H2O is found, for most galaxies, to be the strongest molecular emitter after CO in FTS spectra. The luminosity of the five most important H2O lines is near-linearly correlated with L IR, regardless of whether or not strong active galactic nucleus signature is present. However, the luminosity of H2O(211-202) and H2O(220-211) appears to increase slightly faster than linear with L IR. Although the slope turns out to be slightly steeper when z ~ 2-4 ULIRGs are included, the correlation is still closely linear. We find that L_{H_2O}/L IR decreases with increasing f 25/f 60, but see no dependence on f 60/f 100, possibly indicating that very warm dust contributes little to the excitation of the submillimeter H2O lines. The average spectral line energy distribution (SLED) of the entire sample is consistent with individual SLEDs and the IR pumping plus collisional excitation model, showing that the strongest lines are H2O(202-111) and H2O(321-312). Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Yang, Chentao; Gao, Yu; Omont, A.; Liu, Daizhong; Isaak, K. G.; Downes, D.; van der Werf, P. P.; Lu, Nanyao

2013-07-01

420

Convective Detrainment and Control of the Tropical Water Vapor Distribution  

NASA Astrophysics Data System (ADS)

Sherwood et al. (2006) developed a simple power law model describing the relative humidity distribution in the tropical free troposphere where the power law exponent is the ratio of a drying time scale (tied to subsidence rates) and a moistening time which is the average time between convective moistening events whose temporal distribution is described as a Poisson distribution. Sherwood et al. showed that the relative humidity distribution observed by GPS occultations and MLS is indeed close to a power law, approximately consistent with the simple model's prediction. Here we modify this simple model to be in terms of vertical length scales rather than time scales in a manner that we think more correctly matches the model predictions to the observations. The subsidence is now in terms of the vertical distance the air mass has descended since it last detrained from a convective plume. The moisture source term becomes a profile of convective detrainment flux versus altitude. The vertical profile of the convective detrainment flux is deduced from the observed distribution of the specific humidity at each altitude combined with sinking rates estimated from radiative cooling. The resulting free tropospheric detrainment profile increases with altitude above 3 km somewhat like an exponential profile which explains the approximate power law behavior observed by Sherwood et al. The observations also reveal a seasonal variation in the detrainment profile reflecting changes in the convective behavior expected by some based on observed seasonal changes in the vertical structure of convective regions. The simple model results will be compared with the moisture control mechanisms in a GCM with many additional mechanisms, the GISS climate model, as described in Rind (2006). References Rind. D., 2006: Water-vapor feedback. In Frontiers of Climate Modeling, J. T. Kiehl and V. Ramanathan (eds), Cambridge University Press [ISBN-13 978-0-521- 79132-8], 251-284. Sherwood, S., E. R. Kursinski and W. Read, A distribution law for free-tropospheric relative humidity, J. Clim. In press. 2006

Kursinski, E. R.; Rind, D.

2006-12-01

421

DIURNAL CYCLE OF PRECIPITABLE WATER VAPOR OVER SPAIN  

SciTech Connect

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.

Ortiz de Galisteo, J. P.; Cachorro, V. E.; Toledano, C.; Torres, B.; Laulainen, Nels S.; Bennouna, Yasmine; de Frutos, A. M.

2011-05-20

422

In-flight Performance of the Water Vapor Monitor Onboard the SOFIA Observatory  

NASA Astrophysics Data System (ADS)

NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA) airborne observatory flies in a modified B747-SP aircraft 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 has been developed to observe the strength and shape of the 183GHz rotational line of water, allowing measurements of the integrated water vapor overburden in flight. In order to be useful in correcting the astronomical signals, the required measured precipitable water vapor accuracy must be 2 microns or better, 3 sigma, and measured at least once a minute. The Water Vapor Monitor has flown 22 times during the SOFIA Early Science shared-risk period. The instrument water vapor overburden data obtained were then compared with concurrent data from GOES-V satellites to perform a preliminary calibration of the measurements. This presentation will cover the results of these flights. The final flight calibration necessary to reach the required accuracy will await subsequent flights following the SOFIA observatory upgrade that is taking place during the spring and summer of 2012.

Roellig, Thomas L.; Yuen, L.; Sisson, D.; Hang, R.

2012-05-01

423

Some results of water vapor, ozone and aerosol balloon borne measurements during EASOE  

NASA Astrophysics Data System (ADS)

As part of the European Arctic Stratospheric Ozone Experiment (EASOE) in the northern winter of 1991/92, regular measurements of the vertical distribution of ozone and aerosols were carried out from two Russian polar stations, Heiss Island (81N, 58E) and Dikson Island (73N, 81E). In addition measurements of the vertical distribution of water vapor and aerosols were made from Esrange (68N, 21E), near Kiruna in Sweden. The instruments used were electrochemical ozone sondes (ECC-4A), a fluorescence hygrometer, and the University of Wyoming backscattersonde. Following the eruption of Mt.Pinatubo, in the Philippines, in June 1991, volcanic aerosol had reached Arctic latitudes at altitudes below 19 km by September. At all three sites it was observed on every flight. Polar stratospheric clouds were encountered above the volcanic aerosol on two flights from Esrange. There were no indications of dehydration in the Arctic stratosphere. On all flights the minimum mixing ratio of water vapor was observed 2 to 3 km above the tropopause. Total ozone was much lower than the climatological mean, over Dikson Island from the January 27, and over Heiss Island from mid-February, until the end of EASOE. Ozone profiles over these stations showed rapid increases in partial pressure immediately above the peak values of backscatter ratio when the volcanic aerosol was especially dense.

Khattatov, V.; Yushkov, V.; Khaplanov, M.; Zaitzev, I.; Rosen, J.; Kjome, N.

424

High-sensitive measurement of water vapor: shot-noise level performance via a noise canceller.  

PubMed

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

Wang, Qiang; Chang, Jun; Zhu, Cunguang; Liu, Yongning; Lv, Guangping; Wang, Fupeng; Liu, Xiangzhi; Wang, Zongliang

2013-02-10

425

Some results of water vapor, ozone and aerosol balloon borne measurements during EASOE  

SciTech Connect

As part of the European Arctic Stratospheric Ozone Experiment (EASOE) in the northern winter of 1991/92, regular measurements of the vertical distribution of ozone and aerosols were carried out from two Russian polar stations, Heiss Island (81N, 58E) and Dikson Island (73N, 81E). In addition measurements of the vertical distribution of water vapor and aerosols were made from Esrange (68N, 21E), near Kiruna in Sweden. The instruments used were electrochemical ozone sondes (ECC-4A), a fluorescence hygrometer, and the University of Wyoming backscattersonde. Following the eruption of Mt. Pinatubo, in the Philippines, in June 1991, volcanic aerosol had reached Arctic latitudes at altitudes below 19 km by September. At all three sites it was observed on every flight. Polar stratospheric clouds were encountered above the volcanic aerosol on two flights from Esrange. There were no indications of dehydration in the Arctic stratosphere. On all flights the minimum mixing ratio of water vapor was observed 2 to 3 km above the tropopause. Total ozone was much lower than the climatological mean, over Dikson Island from January 27, and over Heiss Island from mid-February, until the end of EASOE. Ozone profiles over these stations showed rapid increases in partial pressure immediately above the peak values of backscatter ratio when the volcanic aerosol was especially dense. 12 refs., 4 figs.

Khattatov, V.; Yushkov, V.; Khaplanov, M.; Zaitzev, I. (Central Aerological Observatory, Moscow (Russian Federation)); Rosen, J.; Kjome, N. (Univ. of Wyoming, Laramie, WY (United States))

1994-06-22

426

Sticking coefficient and processing of water vapor on organic-coated nanoaerosols.  

PubMed

Organic-based aerosols may play an unexpectedly important role in the atmospheric processing of water vapor. In this paper, we report results of a molecular dynamics (MD) study on the sticking coefficient of water vapor on a coated particle (water droplet coated with fatty acid of radius approximately 4 nm). The sticking coefficient was found to be almost a constant (11-16%) for incident speeds around the most probable speed as opposed to 100% for water vapor incident on a pure water droplet. The sticking coefficient was found to increase with the size of the water cluster (water-Nmer) impinging the surface of the particle and was seen to approach 1 for impinging water clusters consisting of 10 molecules or more. We also computed the average energy transferred per collision for monomers impinging the surface of the coated particle and found the value to be 4.4581 kJ/mol. Most important perhaps was the fact that despite the lower sticking coefficient, the equilibrium vapor pressure of water over these inverted micelles was considerably lower due to the surface tension effects of the fatty acid layer. As such, these coated particles act as effective substrates for water vapor condensation and may play a role as cloud condensation nuclei. PMID:18193845

Chakraborty, Purnendu; Zachariah, Michael R

2008-01-15

427

Validation of water vapor retrieval from SCIAMACHY limb measurements in the upper troposphere and lower stratosphere  

NASA Astrophysics Data System (ADS)

Water vapor is retrieved from scattered solar radiation measured with the SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY). We use data from limb observation geometry in the near infrared spectral range around 1400nm. The water vapor retrieval covers an altitude range of about 12 to 23 km with a vertical resolution between about 2 and 6 km. Multiple scattering must be considered and due to a high amount of water vapor in the troposphere the retrieval is challenging. SCIAMACHY reaches global coverage at the equator within 6 days and measures continuously since 2002. The retrieval from the SCIAMACHY limb mode offer a fairly dense horizontal sampling, good vertical resolution, and a long time series in the upper troposphere and lower stratosphere (UTLS). Here, the retrieved water vapor is compared to several other satellite instruments e.g. ACE-FTS, MIPAS, MLS and in situ measurements.

Weigel, Katja; Rozanov, Alexei; Weber, Mark; Bovensmann, Heinrich; Stiller, Gabriele; Burrows, John P.

428

Physics of the Atmosphere: Response of the Water Vapor Channel of the Meteosat Satellite.  

National Technical Information Service (NTIS)

An accurate model of the atmospheric transmission function is used to obtain the relationship between the cloudless radiances measured by the 6-7 microns Meteosat radiometer (water vapor channel) and the numerical parameters associated to each point of an...

M. Roulleau M. M. Poc N. Scott A. Chedin

1980-01-01

429

New Algorithm for Microwave Delay Estimation from Water Vapor Radiometer Data.  

National Technical Information Service (NTIS)

A new algorithm has been developed for the estimation of tropospheric microwave path delays from water vapor radiometer (WVR) data, which does not require site and weather dependent empirical parameters to produce high accuracy. Instead of taking the conv...

S. E. Robinson

1986-01-01

430

Development of an Improved Membrane for a Vapor Diffusion Water Recovery Process.  

National Technical Information Service (NTIS)

Recovery of potable water from urine on manned space missions of extended duration was the objective of work aimed at the improvement of membrane performance for the vapor diffusion process (VDR). Kynar, Teflon, PVC, and polysulfone candidate membranes we...

T. R. Rich T. W. Mix

1974-01-01

431

Calculational Model for Condensation of Water Vapor during an Underground Nuclear Detonation.  

National Technical Information Service (NTIS)

An empirally derived mathematical model was developed to calculate the pressure and temperature history during condensation of water vapor in an underground-nuclear-explosion cavity. The condensation process is non-isothermal. Use has been made of the Cla...

R. J. Knox

1975-01-01

432

Comparison of Columnar Water-Vapor Measurements from Solar Transmittance Methods  

NASA Astrophysics Data System (ADS)

In the fall of 1997 the Atmospheric Radiation Measurement program conducted a study of water-vapor-abundance-measurement at its southern Great Plains site. The large number of instruments included four solar radiometers to measure the columnar water vapor (CWV) by measuring solar transmittance in the 0.94- m water-vapor absorption band. At first, no attempt was made to standardize our procedures to the same radiative transfer model and its underlying water-vapor spectroscopy. In the second round of comparison we used the same line-by-line code (which includes recently corrected H2 O spectroscopy) to retrieve CWV from all four solar radiometers, thus decreasing the mean CWV by 8 -13%. The remaining spread of 8% is an indication of the other-than-model uncertainties involved in the retrieval.

Schmid, Beat; Michalsky, Joseph J.; Slater, Donald W.; Barnard, James C.; Halthore, Rangasayi N.; Liljegren, James C.; Holben, Brent N.; Eck, Thomas F.; Livingston, John M.; Russell, Philip B.; Ingold, Thomas; Slutsker, Ilya

2001-04-01

433

Comparison of Columnar Water-Vapor Measurements from Solar Transmittance Methods  

SciTech Connect

In the fall of 1997 the Atmospheric Radiation Measurement program conducted a study of water-vapor abundance-measurement at its southern Great Plains site. The large number of instruments included four solar radiometers to measure the columnar water vapor (CWV) by measuring solar transmittance in the 0.94-micrometer water-vapor absorption band. At first, no attempt was made to standardize our procedures to the same radiative transfer model and its underlying water-vapor spectroscopy. In the second round of comparison we used the same line-by-line code (which includes recently corrected H2O spectroscopy) to retrieve CWV from all four solar radiometers, thus decreasing the mean CWV by 813%. The remaining spread of 8% is an indication of the other-than-model uncertainties involved in the retrieval.

Schmid, B; Michalsky, Joseph J.; Slater, Donald W.; Barnard, James C.; Halthore, R; Liljegren, J C.; Holben, B. N.; Eck, T; Livingston, J; Russell, P; Ingold, Thomas; Slutsker, I.

2001-04-20

434

RECIPES FOR WRITING ALGORITHMS TO RETRIEVE COLUMNAR WATER VAPOR FOR 3-BAND MULTI-SPECTRAL DATA.  

SciTech Connect

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.

Borel, C. C. (Christoph C.); Hirsch, K. L. (Karen L.); Balick, L. K. (Lee K.)

2001-01-01

435

Effective parametrization of overlapping water vapor and carbon dioxide absorption bands  

Microsoft Academic Search

This report presents a new effective method which can be used to compute both the transmittance and the atmospheric radiation fluxes in the overlapping water vapor and carbon dioxide absorption bands.

K. M. Firsov; A. A. Mitsel

1997-01-01

436

water vapor transport in the vicinity of imbibing brines in unsaturated porous media  

NASA Astrophysics Data System (ADS)

Water vapor transport in the vicinity of imbibing saline solutions was investigated in 2D chambers using a light transmission technique. Concentrated NaNO_3 solutions (brines) were applied as point sources to the surface of homogenous packs of prewetted silica sand for four different sand grades. The same solutions were applied to layered systems, where two horizontal fine layers were embedded within a coarser matrix, mimicking stratified sedimentary deposits. Water vapor transport from the residually saturated sand into the imbibing brine was observed in all sand grades and geometries. Pure water applied to sand prewetted with brine migrated into the surrounding residual brine. Water vapor stripping was found to enhance the lateral transport of brine in layered sand, where capillary barrier effects play a major role. Our observations suggest that osmotic potential and vapor density lowering in saline solutions, often neglected in predictive models, should be taken into account when predicting the transport of brines in the vadose zone.

Weisbrod, N.; Niemet, M. R.; Selker, J. S.

2003-04-01

437

Microcalorimetric Measurement of the Interactions Between Water Vapor and Amorphous Pharmaceutical Solids  

Microsoft Academic Search

Purpose. Use a microcalorimetric technique to measure the interactions between water vapor and amorphous pharmaceutical solids and describe the relationship between long-term physical stability and the storage relative humidity (RH) at constant temperature.

David Lechuga-Ballesteros; Aziz Bakri; Danforth P. Miller

2003-01-01

438

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

NASA Astrophysics Data System (ADS)

Characterizing water vapor and cloud effects on the surface radiation budget is critical for understanding the current climate because water vapor is the most important greenhouse gas in the atmosphere and clouds are one of the largest sources of uncertainty in predicting potential future climate change. Several studies have shown that insolation over land declined until 1990 then increased until the present. Using 8 years of data collected at the ARM Southern Great Plains (SGP) surface site, we found that the insolation increased from 1997 to 2000, but significantly decreased from 2001 to 2004, changes that exactly mirror the variation in the second-order fit of cloud fraction. Under clear-sky conditions, the rates of change of water vapor, insolation and downwelling longwave (LW) flux are -0.0166 cm/yr, 0.48 Wm-2/yr, and -1.16 Wm-2/yr, respectively, indicating that water vapor changes are more important for LW flux than for insolation.

Dong, Xiquan; Xi, Baike; Minnis, Patrick

2006-10-01

439

Seasonal to decadal variations of water vapor in the tropical lower stratosphere observed with balloon-borne cryogenic frost point hygrometers  

Microsoft Academic Search

We investigated water vapor variations in the tropical lower stratosphere on seasonal, quasi-biennial oscillation (QBO), and decadal time scales using balloon-borne cryogenic frost point hygrometer data taken between 1993 and 2009 during various campaigns including the Central Equatorial Pacific Experiment (March 1993), campaigns once or twice annually during the Soundings of Ozone and Water in the Equatorial Region (SOWER) project

M. Fujiwara; H. Vömel; F. Hasebe; M. Shiotani; S.-Y. Ogino; S. Iwasaki; N. Nishi; T. Shibata; K. Shimizu; E. Nishimoto; J. M. Valverde Canossa; H. B. Selkirk; S. J. Oltmans

2010-01-01

440

Estimation of 3-D Water vapor distribution using a network of compact microwave radiometers  

Microsoft Academic Search

Quantitative precipitation forecasting is limited by the paucity of observations of water vapor in the troposphere. In particular, severe storms have been observed to develop in regions of strong and rapidly evolving moisture gradients. Conventional measurements of water vapor density profiles are obtained using in-situ probes on-board weather balloons, including radiosondes. These in-situ profile measurements have high vertical resolution, but

S. Padmanabhan; S. C. Reising; F. Iturbide-Sanchez; I. J. Vivekanandan

2007-01-01

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