Retrieval of greenhouse gases from GOSAT and GOSAT-2 using the FOCAL algorithm

Atmospheric Measurement Techniques

article

Stefan Noël¹  Maximilian Reuter¹  Michael Buchwitz¹  Jakob Borchardt¹  Michael Hilker¹  Oliver Schneising¹  Heinrich Bovensmann¹  John P. Burrows¹  Antonio Di Noia²  Robert J. Parker²  Hiroshi Suto⁴  Yukio Yoshida⁵  Matthias Buschmann¹  Nicholas M. Deutscher⁶  Dietrich G. Feist⁷  David W. T. Griffith⁶  Frank Hase^1,10  Rigel Kivi^1,11  Cheng Liu^1,12  Isamu Morino⁵  Justus Notholt¹  Young-Suk Oh^1,13  Hirofumi Ohyama⁵  Christof Petri¹  David F. Pollard^1,14  Markus Rettinger^1,10  Coleen Roehl^1,15  Constantina Rousogenous^1,16  Mahesh Kumar Sha^1,17  Kei Shiomi⁴  Kimberly Strong^1,18  Ralf Sussmann^1,10  Yao Té^1,19  Voltaire A. Velazco⁶  Mihalis Vrekoussis^1,16  Thorsten Warneke¹ 

[1] Institute of Environmental Physics, University of Bremen;Earth Observation Science, University of Leicester;National Centre for Earth Observation, University of Leicester;Japan Aerospace Exploration Agency;National Institute for Environmental Studies;Centre for Atmospheric Chemistry, School of Earth, Atmospheric and Life Sciences, University of Wollongong;Max Planck Institute for Biogeochemistry;Deutsches Zentrum für Luft- und Raumfahrt, Institut für Physik der Atmosphäre;Ludwig-Maximilians-Universität München;Karlsruhe Institute of Technology;Finnish Meteorological Institute, Space and Earth Observation Centre;Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China;Global Atmosphere Watch Team, Innovative Meteorological Research Department, National Institute of Meteorological Sciences;National Institute of Water and Atmospheric Research Ltd ,(NIWA), Lauder, Private Bag 50061;California Institute of Technology, Global Environmental Center;Climate and Atmosphere Research Center ,(CARE-C), The Cyprus Institute;Royal Belgian Institute for Space Aeronomy;Department of Physics, University of Toronto;Laboratoire d"Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères ,(LERMA-IPSL), Sorbonne Université, CNRS, Observatoire de Paris, PSL Université;Deutscher Wetterdienst;Center of Marine Environmental Sciences ,(MARUM), University of Bremen

DOI  :  10.5194/amt-15-3401-2022

学科分类：内科医学

来源: Copernicus Publications

【 摘 要 】

We show new results from an updated version of the Fast atmOspherictraCe gAs retrievaL (FOCAL) retrieval method applied to measurementsof the Greenhouse gases Observing SATellite (GOSAT) and its successorGOSAT-2.FOCAL was originally developed for estimating the total column carbondioxide mixing ratio ( XCO 2 ) from spectral measurements made by theOrbiting Carbon Observatory-2 (OCO-2).However, depending on the available spectral windows, FOCAL alsosuccessfully retrieves total column amounts for other atmosphericspecies and their uncertainties within one single retrieval.The main focus of the current paper is on methane ( XCH 4 ; full-physics and proxy product), water vapour ( XH 2 O ) and therelative ratio of semi-heavy water ( HDO ) to water vapour( δ D ).Due to the extended spectral range of GOSAT-2, it is also possible toderive information on carbon monoxide ( XCO ) and nitrous oxide( XN 2 O ) for which we also show first results.We also present an update on XCO 2 from both instruments. For XCO 2 , the new FOCAL retrieval (v3.0) significantly increasesthe number of valid data compared with the previous FOCAL retrievalversion (v1) by 50 % for GOSAT and about a factor of 2 for GOSAT-2due to relaxed pre-screening and improved post-processing.All v3.0 FOCAL data products show reasonable spatial distribution andtemporal variations.Comparisons with the Total Carbon Column Observing Network (TCCON) resultin station-to-station biases which are generally in line with thereported TCCON uncertainties. With this updated version of the GOSAT-2 FOCAL data, we provide afirst total column average XN 2 O product.Global XN 2 O maps show a gradient from the tropicsto higher latitudes on the order of 15  ppb , which can beexplained by variations in tropopause height.The new GOSAT-2 XN 2 O product compares well with TCCON.Its station-to-station variability is lower than 2  ppb ,which is about the magnitude of the typical N 2 O variations close to the surface.However, both GOSAT-2 and TCCON measurements show that the seasonalvariations in the total column average XN 2 O are on the orderof 8  ppb peak-to-peak, which can be easily resolved by the GOSAT-2 FOCALdata.Noting that only few XN 2 O measurements from satellites exist sofar, the GOSAT-2 FOCAL product will be a valuable contribution inthis context.

【 授权许可】

CC BY