Ten-Year Assessment of IASI Radiance and Temperature

Remote Sensing

Elsa Jacquette¹  Dorothée Coppens²  Marie Doutriaux-Boucher²  Thomas August²  Juliette Hadji-Lazaro³  Sarah Safieddine³  Cathy Clerbaux³  Marie Bouillon³  Lieven Clarisse⁴  Simon Whitburn⁴ 

[1]Centre National d’Etudes Spatiales, 31400 Toulouse, France

[2]European Organisation for the Exploitation of Meteorological Satellites, 64295 Darmstadt, Germany

[3]LATMOS/IPSL, Sorbonne Université, UVSQ, CNRS, 75005 Paris, France

[4]Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium

关键词: IASI;    climate studies;    radiance;    atmospheric temperature;    surface temperature;    atmospheric composition;   

DOI  :  10.3390/rs12152393

来源: DOAJ

【 摘 要 】

The Infrared Atmospheric Sounding Interferometers (IASIs) are three instruments flying on board the Metop satellites, launched in 2006 (IASI-A), 2012 (IASI-B), and 2018 (IASI-C). They measure infrared radiance from the Earth and atmosphere system, from which the atmospheric composition and temperature can be retrieved using dedicated algorithms, forming the Level 2 (L2) product. The operational near real-time processing of IASI data is conducted by the EUropean organisation for the exploitation of METeorological SATellites (EUMETSAT). It has improved over time, but due to IASI’s large data flow, the whole dataset has not yet been reprocessed backwards. A necessary step that must be completed before initiating this reprocessing is to uniformize the IASI radiance record (Level 1C), which has also changed with time due to various instrumental and software modifications. In 2019, EUMETSAT released a reprocessed IASI-A 2007–2017 radiance dataset that is consistent with both the L1C product generated after 2017 and with IASI-B. First, this study aimed to assess the changes in radiance associated with this update by comparing the operational and reprocessed datasets. The differences in the brightness temperature ranged from 0.02 K at 700 cm⁻¹ to 0.1 K at 2200 cm⁻¹. Additionally, two major updates in 2010 and 2013 were seen to have the largest impact. Then, we investigated the effects on the retrieved temperatures due to successive upgrades to the Level 2 processing chain. We compared IASI L2 with ERA5 reanalysis temperatures. We found differences of ~5–10 K at the surface and between 1 and 5 K in the atmosphere. These differences decreased abruptly after the release of the IASI L2 processor version 6 in 2014. These results suggest that it is not recommended to use the IASI inhomogeneous temperature products for trend analysis, both for temperature and trace gas trends.

【 授权许可】

Unknown