Time evolution of temperature profiles retrieved from 13 years of infrared atmospheric sounding interferometer (IASI) data using an artificial neural network

• Published in: Atmospheric Measurement Techniques
• Main Authors: Bouillon, Marie, Safieddine, Sarah, Whitburn, Simon, Clarisse, Lieven, Aires, Filipe, Pellet, Victor, Lezeaux, Olivier, Scott, Noëlle, A., Doutriaux-Boucher, Marie, Clerbaux, Cathy
• Other Authors: TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing (SQUARES), Université libre de Bruxelles (ULB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris Sciences et Lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Sté SPASCIA, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; North Pole
• Online Access: https://insu.hal.science/insu-03407369; https://insu.hal.science/insu-03407369v2/document; https://insu.hal.science/insu-03407369v2/file/amt-15-1779-2022.pdf; https://doi.org/10.5194/amt-15-1779-2022

International audience The three IASI instruments, launched in 2006, 2012, and 2018, are key instruments to weather forecasting, and most meteorological centers assimilate IASI nadir radiance data into atmospheric models to feed their forecasts. The EUropean organisation for the exploitation of METeorological SATellites (EUMETSAT) recently released a reprocessed homogeneous radiance record for the whole IASI observation period, from which thirteen years (2008-2020) of temperature profiles can be obtained. In this work, atmospheric temperatures at different altitudes are retrieved from IASI radiances measured in the carbon dioxide absorption bands (654-800 cm-1 and 2250-2400 cm-1) by selecting the channels that are the most sensitive to the temperature at different altitudes. We rely on an Artificial Neural Network (ANN) to retrieve atmospheric temperatures from a selected set of IASI radiances. We trained the ANN with IASI radiances as input and the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis version 5 (ERA5) as output. The retrieved temperatureswere validated with ERA5, with in situ radiosonde temperatures from the Analysed RadioSoundings Archive (ARSA)network and with EUMETSAT temperatures retrieved fromIASI radiances using a different method. Between 750 and7 hPa, where IASI is most sensitive to temperature, a goodagreement is observed between the three datasets: the differences between IASI on one hand and ERA5, ARSA, orEUMETSAT on the other hand are usually less than 0.5 Kat these altitudes. At 2 hPa, as the IASI sensitivity decreases,we found differences up to 2 K between IASI and the threevalidation datasets. We then computed atmospheric temperature linear trends from atmospheric temperatures between750 and 2 hPa. We found that in the past 13 years, there is ageneral warming trend of the troposphere that is more important at the poles and at mid-latitudes (0.5 K/decade at mid-latitudes, 1 K/decade at the North Pole). The stratosphereis globally cooling on average, except at the ...