Detection of ...First Results_Dongxu YANG.pdf

Detection of Anthropogenic CO2 Emission Signatures with TanSat CO2and with Copernicus Sentinel-5 Precursor(S5P)NO2Measurements:First ResultsDongxu YANG*1,Janne HAKKARAINEN2,Yi LIU1,Iolanda IALONGO2,Zhaonan CAI1,and Johanna TAMMINEN21Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China2Finnish Meteorological Institute,Helsinki FI-00560,Finland(Received 29 August 2022;revised 8 October 2022;accepted 10 October 2022)ABSTRACTChinas first carbon dioxide(CO2)measurement satellite mission,TanSat,was launched in December 2016.Thispaper introduces the first attempt to detect anthropogenic CO2 emission signatures using CO2 observations from TanSat andNO2 measurements from the TROPOspheric Monitoring Instrument (TROPOMI)onboard the Copernicus Sentinel-5Precursor(S5P)satellite.We focus our analysis on two selected cases in Tangshan,China and Tokyo,Japan.We found thatthe TanSat XCO2 measurements have the capability to capture the anthropogenic variations in the plume and have spatialpatterns similar to that of the TROPOMI NO2 observations.The linear fit between TanSat XCO2 and TROPOMI NO2indicates the CO2-to-NO2 ratio of 0.8 1016 ppm(molec cm2)1 in Tangshan and 2.3 1016 ppm(molec cm2)1 inTokyo.Our results align with the CO2-to-NOx emission ratios obtained from the EDGAR v6 emission inventory.Key words:TanSat,CO2,Remote sensing,city carbon emission,climate changeCitation:Yang,D.X.,J.Hakkarainen,Y.Liu,I.Ialongo,Z.N.Cai,and J.Tamminen,2023:Detection of anthropogenicCO2 emission signatures with TanSat CO2 and with Copernicus Sentinel-5 Precursor(S5P)NO2 measurements:First results.Adv.Atmos.Sci.,40(1),15,https:/doi.org/10.1007/s00376-022-2237-5.1.IntroductionBy absorbing infrared radiation,greenhouse gases trap heat in the Earths atmosphere,which would otherwise escapeinto space,and greenhouse gas concentrations in the atmosphere have increased since the onset of the industrial revolution.In the 2015 United Nations Climate Change Conference held in Paris,participants agreed to reduce greenhouse gas emissionsto prevent an average global surface temperature increase of more than 1.5C.Hence,mitigating or slowing down globalwarming represents a challenge faced by the global population in the 21st century.Concentrations of carbon dioxide(CO2)have risen by more than 40%due to anthropogenic activities such as fossil fuel combustion and land-use change.The emissionsrelated to the combustion of fossil fuels are particularly localized,with urban areas being the dominant contributor responsiblefor more than 70%of global emissions.Even though global economies are struggling due,in part,to the recovery from the impact of COVID-19,in 2021,fossil-fuel-related CO2 emissions have shown an increase of 5%with an uncertainty of 5%(Friedlingstein et al.,2022).Largeuncertainty remains in fossil-fuel emission estimates when focused on specific countries(Andres et al.,2014),and uncertaintiesare even larger than expected for cities(Ciais et al.,2014;Gately et al.,2015;Miller and Michalak,2017;Gately andHutyra,2017;Oda et al.,2018;Gurney et al.,2019).For example,one investigation indicates a 20.4%variation in the fossil-fuel emission estimates of Los Angeles,while variations exceeding 200%were found in Beijing(Han et al.,2020).The uncer-tainty mainly comes from two parts,the remaining bias in the emission inventory statistics,for example,less than optimalestimations of energy consumption and emission factors(Liu et al.,2015),and the inability to adequately capture therapidly increasing magnitude of fossil-fuel consumption related to economic growth,which is not updated in a timely man-ner.*Corresponding author:Dongxu YANGEmail:ADVANCES IN ATMOSPHERIC SCIENCES,VOL.40,JANUARY 2023,15 News&Views Institute of Atmospheric Physics/Chinese Academy of Sciences,and Science Press and Springer-Verlag GmbH Germany,part of Springer Nature 2023To better understand the uncertainty of carbon emissions(sources)and sinks,satellite missions dedicated to atmosphericgreenhouse measurements have been developed in the last decade.Chinas Global Carbon Dioxide Monitoring ScientificExperimental Satellite(TanSat)was launched in December 2016 after Japans Greenhouse gases Observing SATellite(GOSAT,2009)(Kuze et al.,2009)and NASAs Orbiting Carbon Observatory-2(OCO-2,2014)(Crisp et al.,2017)mis-sion.Similar to the OCO-2 mission,TanSat has a hyperspectral grating spectrometer covering the near-infrared(NIR)andshort-wave infrared(SWIR)regions that are sensitive to CO2 absorption(Liu and Yang,2016).The nadir footprint size ofTanSat measurement is 2 2 km2,and it has nine footprints across the track in a frame,which means TanSat has the potentialto capture anthropogenic emission enhancements in a city and downwind of a power station.The CEOS Chair commissioned the Atmospheric Composition Virtual Constellation(AC-VC)to define a global architec-ture for monitoring atmospheric greenhouse gas concentrations and their fluxes from space(Crisp et al.,2018).Quanti