D.N. Whiteman¹, M. Adam², C. Barnet¹³, B. Bojkov⁵, J. Comer¹⁴, B. Demoz¹, J. Fitzgibbon⁴, R. Forno¹²,R. Herman⁸,R. Hoff³,E. Joseph²,E. Landulfo¹¹,K. McCann³,T. McGee¹,L. Miloshevich⁵,I. Restrepo¹⁰,F. Schmidlin¹,B. Taubman⁷,A. M. Thompson⁷,L. Twigg¹⁴,D. Venable²,H. Vimel⁶,C. Walthall⁹

¹NASA/Goddard Space Flight Center, Greenbelt, MD, 20771, USA
²Howard University, Washington, DC, 20059, USA
³University of Maryland, Baltimore County, Baltimore, MD, 21250, USA
⁴NOAA/National Weather Service, Sterling, VA, 20166, USA
⁵National Center for Atmospheric Research, Boulder, CO, 80305, USA
⁶University of Colorado (CIRES) , Boulder, CO, 80309, USA
⁷Pennsylvannia State University, University Park, PA, 16802, USA
⁸Jet Propulsion Lab, Pasadena, CA, 91109, USA
⁹US Department of Agriculture, Beltsville, MD, 20705, USA
¹⁰Trinity University, Washington, DC, 20017, USA
¹¹Instituto de Pesquisas Energéticas e Nucleares, IPEN, São Paulo, Brazil
¹²University Mayor de San Andres, La Paz, Bolivia
¹³NOAA/NESDIS, Camp Springs, MD, 20746, USA
¹⁴Science Systems Applications Inc., Lanham, MD, 20706, USA

The NASA Aura satellite was launched on July 15, 2004 and is the trailing member of the “A-train” series of satellites. A field campaign called WAVES 2006 (Water Vapor Variability Satellite/Sondes) was hosted at the Howard University Research Campus in Beltsville, MD from July 7 August 12, 2006 to provide research quality measurements of ozone, temperature, pressure and water vapor for comparison with Aura satellite retrievals and for instrument accuracy assessment studies. Because of the small difference in overpass time, WAVES 2006 measurements are also being used for Aqua satellite retrieval studies. The Howard University site was selected to host WAVES because of the extensive suite of atmospheric measurement instrumentation hosted 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 (Radio Acoustic Sounding System) system. WAVES also brought together researchers from several U.S government agencies and universities as well as foreign institutions. As such it provided a unique training opportunity for students in the atmospheric sciences. Undergraduate and graduate students from both the U.S and several foreign countries participated. Students were 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 thirty-seven overpasses of the Aura satellite. Special “staring-mode” observations of the Beltsville region were performed by the TES (Tropospheric Emission Spectrometer) instrument during WAVES, which increased the amount of coincident data for evaluating an updated TES ozone retrieval algorithm. NOAA/NESDIS provided AIRS water vapor and ozone retrievals using both the near real-time system running the AIRS science team version 4 algorithm and a research algorithm incorporating the latest algorithm improvements planned for version 5. 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 was also 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 (Accurate Temperature Measurement) 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 the AWEX, an experiment in 2003 that served as a model for the radiosonde intercomparison/satellite validation activities that occurred during WAVES. 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 backscatter Lidar from Penn State. Coordinated backscatter (Elastic Lidar Facility) and Raman (Atmospheric Lidar Experiment) lidar measurements occurred at the University of Maryland, Baltimore County and at NASA/GSFC in Greenbelt, MD (Raman Airborne Spectroscopic Lidar operating from the ground). 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. The U.S. Department of Agriculture deployed a sun-photometer member of the AERONET network for use during WAVES. A member of the SuomiNet network of GPS systems was deployed by NASA/GSFC for total column water measurements. An overview of theWAVES campaign and preliminary comparison of surface-based and satellite measurements will be presented at the conference along with results relating an algorithm intercomparison effort that has been initiated.