Validation of FORMOSAT-3/COSMIC level 2 "atmPrf" global temperature data in the stratosphere
Abstract
Abstract. GPS radio occultations by Formosa Satellite mission-3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC) provide refractivity profiles, which are processed real-time to give profiles of temperature and water vapour in the lower atmosphere and electron density in the upper atmosphere. The new "atmPrf" (atmospheric profile) product gives temperature from surface to 0.2 hPa (~60 km). This is a dry temperature data product that does not include relative humidity in the inversion process and hence is reliable at and above the tropopause (>100 hPa) and erroneous in the troposphere (<100 hPa). In the current study we compare the COSMIC "atmPrf" data during December 2010 to November 2011 with other satellite (SABER/TIMED and MLS/Aura) temperatures from 50 to 0.2 hPa and reanalysis (NCEP, ERA-Interim and UKMO) outputs at 100, 10, 1 and 0.5 hPa pressure levels. The satellite comparisons show that the observed median differences are most likely produced due to the biases in the retrievals of SABER and MLS. When compared to reanalysis outputs, COSMIC seasonal means match NCEP and ECMWF seasonal mean temperatures very well, especially at 100 and 10 hPa. Comparison with radiosonde measured temperatures over Taipei (25° N, 121.5° E) in the lower altitudes also show very small differences. We conclude from this study that with the new COSMIC dry temperature retrievals obtained from radio occultations of GPS, there is a 20 km extension of reliable data in the middle atmosphere. "atmPrf" data are of good quality and provide reliable and unprecedentedly large number of profiles at greater temporal and spatial resolutions for further studies and investigations of the middle atmosphere up to 1 hPa, i.e., approximately up to the stratopause.
Publisher
Copernicus GmbH
Reference24 articles.
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