4.4
Water Vapor Validation Experiment - Satellite/Sondes - Overview and preliminary results
David N. Whiteman, NASA/GSFC, Greenbelt, MD; and B. B. Demoz, E. Joseph, D. Venable, R. M. Hoff, B. Bojkov, T. McGee, A. M. Thompson, B. F. Taubman, H. Vömel, L. Miloshevich, J. Ftizgibbon, F. J. Schmidlin, C. D. Barnet, and I. M. Restrepo
The NASA AURA satellite was launched on July 15, 2004 and is the trailing member of the “A-train” series of satellites. AURA carries the HIRDLS (High Resolution Dynamics Limb Sounder), MLS (Microwave Limb Sounder), OMI (Ozone Monitoring Instrument) and TES (Tropospheric Emission Spectrometer) instruments. Among the main goals of the AURA mission is the quantification of atmospheric water vapor, ozone and air quality using these instruments. A field campaign called WAVES_2006 (Water Vapor Validation Experiment – Satellite/Sondes) was held this past summer to provide research quality measurements of these and other quantities for comparison with AURA satellite retrievals and for instrument accuracy assessment studies. Because of the small difference in overpass time, we will also be studying Aqua satellite retrievals.
WAVES_2006 (http://ecotronics.com/lidar-misc/WAVES.htm)was hosted at the Howard University Research Campus in Beltsville, MD officially from July 7 – August 10, 2006. The Howard University site was selected to host WAVES because of the extensive suite of atmospheric measurement instrumentation sited there through the support of NOAA and cooperative agreements with the Maryland Department of the Environment (MDE) and WTTG FOX television. Measurements of surface latent heat and carbon dioxide fluxes, boundary layer height and evolution, cloud optical and physical properties, aerosols, gas concentrations, and precipitation are available to support intensive field operations such as WAVES. The measurement systems include 31-m instrumented tower, various broad-band and spectral radiometers, microwave radiometer, whole sky imager, Raman lidar and Doppler C-band radar. Research level air quality monitoring is also conducted at a collocated site operated by MDE. A complete set of gas, filter (including 56 organic species) and particulate measurements (PM2.5 and 10) are made at this site along with surface meteorology and upper air observations with a wind profiler and RASS system.
WAVES is serving to bring together researchers from several U.S government agencies and universities and foreign institutions as well. As such it provides a unique training opportunity for students in the atmospheric sciences. Undergraduate and graduate students from both the U.S and several foreign countries will be participating. Students will be involved in ozonesonde preparation and launch, lidar data acquisition and analysis and in performing daily regional forecasts using the Weather Research and Forecasting (WRF) model.
The operations plan for WAVES included intensive observations by multiple radiosonde/ozonesonde sensors and several lidar systems during approximately 30 overpasses of the AURA satellite. Special “staring-mode” observations of the Beltsville region were programmed for the TES instrument during the period of the WAVES campaign which increased the amount of coincident data for evaluating an updated TES ozone retrieval algorithm. Quick turn-around water vapor and ozone retrievals were provided by the AIRS team at NOAA/NESDIS for comparison. Radiosonde systems manufactured by Vaisala (RS92 and RS80), Intermet and Sippican were tested during WAVES. The National Weather Service (NWS) began deploying the Sippican package in March 2006 to several of its upper-air launch sites. NWS will also be engaged in Consensus Reference Testing, which involves evaluating data from a suite of technologies in order to converge on a statistical and repeatable set of acceptable thresholds for a particular parameter under review. Research-grade balloon borne packages that were used during WAVES included the University of Colorado Cryogenic Frostpoint Hygrometer (CFH) and the NASA/GSFC ATM multi-thermistor radiosonde system. The ATM instrument uses 3 temperature sensors with different emissivity characteristics to provide an improved measurement of atmospheric temperature. The CFH is the instrument that was used as the water vapor reference sensor during AWEX-G [1,2], an experiment in 2003 that will serve as a model for the radiosonde intercomparison/satellite validation activities that will result from the WAVES measurements. Lidar measurements were acquired at the Beltsville site during WAVES by the permanently stationed Howard University Raman Lidar (HURL) and by the visiting NASA/GSFC Scanning Raman Lidar (SRL) and Aerosol/Temperature Lidar (ATL) and a MicroPulse Lidar from Penn State. Coordinated backscatter (Elastic Lidar Facility) and Raman (Atmospheric Lidar Experiment) lidar measurements also were obtained from the University of Maryland, Baltimore County. These coordinated lidar measurements from three sites separated by 10-30 km will permit the spatial variability of aerosols and water vapor to be studied on scales of interest in satellite retrievals. The Penn State University NATIVE trailer containing extensive gas sampling and radiation measurement instrumentation was also deployed to the Beltsville site for WAVES. The measurements from this system are being compared with comparable measurements from the MDE instrumentation adding to the confidence level of the trace gas validation data. A member of the SuomiNet network of GPS systems is being lent by NASA/GSFC for total column water measurements. More details of the WAVES operations and preliminary science results will be described at the symposium.
References
1. Whiteman, D. N., F. Russo, L. Miloshevich, B. Demoz, Z. Wang, I. Veselovskii, H. Voemel, S. Hannon, B. Lesht, F. Schmidlin, A. Gambacorta, C. Barnet, Analysis of Raman lidar and radiosonde measurements from the AWEX-G field campaign and its relation to Aqua validation, J. Geophys. Res., 111, D09S09, doi:10.1029/2005JD006429 (2006).
2. Miloshevich, L. M., H. Voemel, D. N. Whiteman, B. Lesht, F. J. Schmidlin, and F. Russo (2006), Absolute accuracy of water vapor measurements from six operational radiosonde types launched during AWEX-G and implications for AIRS validation, J. Geophys. Res., 111, doi:10.1029/2005JD006083 (2006)
.Session 4, Lidar and Integrated Observations Within Large Field Programs
Wednesday, 17 January 2007, 1:30 PM-3:00 PM, 207B
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