Open AccessCross‐validation of MIPAS/ENVISAT and GPS‐RO/CHAMP temperature profiles
Author(s) -
Wang DingYi,
Stiller Gabriele P.,
von Clarmann Thomas,
Fischer Herbert,
LópezPuertas Manuel,
Funke Bernd,
Glatthor Norbert,
Grabowski Udo,
Höpfner Michael,
Kellmann Sylvia,
Kiefer Michael,
Linden Andrea,
Tsidu Gizaw Mengistu,
Milz Mathias,
Steck Tilman,
Jiang Jonathan H.,
Ao Chi O.,
Manney Gloria,
Hocke Klemens,
Wu Dong L.,
Romans Larry J.,
Wickert Jens,
Schmidt Torsten
Publication year - 2004
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004jd004963
Subject(s) - radio occultation , global positioning system , remote sensing , environmental science , geodesy , atmospheric sounding , depth sounding , jet propulsion , troposphere , satellite , meteorology , geology , ionosphere , physics , geophysics , telecommunications , oceanography , astronomy , computer science , thermodynamics
The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on board the ENVISAT and the Global Positioning System (GPS) receiver on the Challenging Mini‐Satellite Payload (CHAMP) provide temperature profiles by limb‐viewing midinfrared emission and radio occultation (RO) measurements, respectively. The MIPAS temperatures retrieved at the Institut für Meteorologie und Klimaforschung (IMK) are compared with the GPS‐RO/CHAMP observations derived at Jet Propulsion Laboratory (JPL) and GeoForschungsZentrum (GFZ) Potsdam. The three data sets show generally good agreement. The global mean differences averaged between 8 and 30 km in 14 days of September/October 2002 are −0.44 ± 0.02 K and 0.07 ± 0.02 K for MIPAS/GPS‐RO JPL and GFZ comparisons, respectively. The MIPAS global mean temperatures below 25 km are slightly lower than those of GPS‐RO JPL and GFZ by less than 1 K and 0.2 K, respectively. Above 25 km, the MIPAS temperatures are higher than the JPL and GFZ data, in particular near both poles and the equator, with maxima of 1 K for JPL and 1.5 K for GFZ at 30 km. The standard deviations are ∼2–4 K. Possible explanations for the observed differences include (1) effect of spatial and temporal mismatch between the correlative measurements on the observed standard deviations, in particular in regions and episodes of enhanced wave activity; (2) a negative bias in GPS‐RO/CHAMP temperatures in regions of increased humidity; (3) a mapping of initialization temperature profiles on GPS‐RO/CHAMP retrievals at altitudes where low refraction contains no information on air density; and (4) measurement errors of both instruments, particularly the errors due to insufficient knowledge of the instrument line shape and spectroscopy in current MIPAS retrievals.