Assessing the Accuracy of Temperature and Water Vapor Profiles from AIRS, ECMWF, and
NCEP under Cloudy Conditions using COSMIC
Patrick Callaghan
1
, Shu-peng Ho
1,2
, Thomas P. Yunck
3
, Brian D. Wilson
4
, Doug Hunt
1
1 University Corporation for Atmospheric Research,P.O. Box 3000, Boulder, CO, 80307
2 National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO, 80307
3
Foundation for Earth Science, 3839 Calmes Neck Lane, Boyce, Virginia, 22620
4 Jet Propulsion Laboratory, California Institute of Technology, M/S 138-308, 4800 Oak Grove Drive,
Pasadena, CA 91109
Abstract
Infrared measurements from the Atmospheric Infrared Sounder (AIRS) cannot be used to retrieve atmospheric information below clouds. Under those conditions, temperature and water vapor retrievals are only possible after the observed radiances have been adjusted through a cloud-clearing procedure. Radio occultation (RO) measurements provide atmospheric information utilizing a radio wavelength unaffected by the presence of clouds. In this study, we collocate AIRS profiles with RO data from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) to assess the accuracy of temperature and water vapor profiles under cloudy conditions. Results of
AIRS-COSMIC temperature and moisture pairs over land and ocean for both clear and cloudy conditions are presented. To determine if COSMIC RO data can also be used to assess the accuracy of temperature and moisture analyses from the National Centers for Environmental Prediction (NCEP) and European Centre for Medium Range Forecasts (ECMWF) under cloudy conditions, both ECMWF and NCEP were interpolated to the time and location of AIRS-COSMIC sounding pairs. Results show that the ECMWF analysis agrees with COSMIC better than NCEP under cloudy conditions, while statistics of ECMWF-COSMIC pairs are similar with those from NCEP-COSMIC pairs under clear sky conditions.