2023年亚洲气候状况报告 State of the Climate in Asia 2023 -世界气象组织

WEATHERCUMATEWATER

StateoftheClimateinAsia

《山仁

⑤

2023

WORLD

METEOROLOGICAL

ORGANIZATION

WMO.No.1350

WMO-No.1350

WorldMeteorologicalOrganization,2024

Therightofpublicationinprint,electronicandanyotherformandinanylanguageisreservedbyWMO.ShortextractsfromWMOpublicationsmaybereproducedwithoutauthorization,providedthatthecompletesourceisclearlyindicated.Editorialcorrespondenceandrequeststopublish,reproduceortranslatethispublicationinpartorinwholeshouldbeaddressedto:

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WorldMeteorologicalOrganization(WMO)7bis,avenuedelaPaix

P.0.Box2300

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Tel.:+41(0)227308403

Email:publications@

ISBN978-92-63-11350-4

Coverillustration:Yangtzeriver,YunnanProvince,China.Source:AdobeStock

NOTE

ThedesignationsemployedinWMOpublicationsandthepresentationofmaterialinthispublicationdonotimplytheexpressionofanyopinionwhatsoeveronthepartofWMOconcerningthelegalstatusofanycountry,territory,cityorarea,orofitsauthorities,orconcerningthedelimitationofitsfrontiersorboundaries.

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Thefindings,interpretationsandconclusionsexpressedinWMOpublicationswithnamedauthorsarethoseoftheauthorsaloneanddonotnecessarilyreflectthoseofWMOoritsMembers.

i

Contents

Keymessages ii

Foreword ili

Preface iv

Globalclimatecontext

1

Regionalclimate

2

Temperature

2

Precipitation

4

Cryosphere

5

Sea-surfacetemperature

9

Oceanheatcontent

10

Sealevel

11

Majorclimatedrivers

12

Extremeevents

14

Tropicalcyclones

14

Heavyprecipitationandflooding

15

Droughts

16

Heatwavesandwildfires

16

Marineheatwaves

17

Otherextremeevents

18

Climate-relatedimpactsandrisks

20

Mortalityandaffectedpopulation

20

StatusofearlywarningsystemsinAsia

21

EarlywarningandanticipatoryactioninAsia

22

Challengesandopportunities

23

Datasetsandmethods

25

Listofcontributors

28

Endnotes

29

Weneedyourfeedback

Thisyear,theWMOteamhaslaunchedaprocesstogatherfeedbackontheStateoftheClimatereportsandareasforimprovement.Onceyouhavefinishedreadingthepublication,weaskthatyoukindlygiveusyourfeedbackbyrespondingtothisshortsurvey.Yourinputishighlyappreciated

Keymessages

In2023,themeantemperatureoverAsia

period,thesecondhighestonrecord.

was0.91℃abovethe1991-2020reference

Manypartsoftheregionexperienced

experienceditshottestsummeronrecord.

extremeheateventsin2023.Japan

GlaciersinHigh-MountainAsiahavelostsignificantmassoverthepast40years,atanacceleratingrate.In2023,record-breakinghightemperaturesanddrierconditionsintheEasternHimalayasandtheTienShan(mountainrange)exacerbatedmassloss.

warmingtrendsincetimeseriesbegan

in1982.In2023,sea-surfacetemperature

TheoceanaroundAsiahasshownanoverall

werethehighestonrecord.

anomaliesinthenorth-westPacificOcean

South-westChinasufferedfromadrought,withbelow-normalprecipitationlevelsnearlyeverymonthof2023.EssentialwinterprecipitationwasalsobelownormalintheHinduKushregion,andtherainsassociatedwiththeIndiansummermonsoonwere

insufficient.

In2023,over80%ofreportedhydromete-orologicalhazardsinAsiawerefloodandstormevents.Yemensufferedheavyrainfallandresultingwidespreadfloods,withover30reportedcasualtiesandover165000in-dividualsaffectedinover70districts.

Overall,the79reportedhydrometeoro-logicalhazardeventsin2023ledtoover2000fatalitiesandimpactedmorethan9millionpeople.

Approximately80%ofWMOMembers

intheregionprovideclimateservicesto

supportdisasterriskreductionactivities.

However,thereisagapinclimateprojections

andtailoredproducts(providedbyless

than50%ofMembersinWMORegional

Associationl(Asia))thatareneededto

informriskmanagementandadaptation

toandmitigationofclimatechangeandits

impacts.

iii

Foreword

Weareatacriticaljuncture,wheretheimpactofclimatechangeintersectswithsocietalinequalities.Itisimperativethatouractionsandstrategiesmirrortheurgencyofthesetimes.Reducinggreenhousegasemissionsandadaptingtotheevolvingclimateisnotmerelyanoption,butafundamentalnecessity.

WMOiscommittedtoprovidingscienceandservicesthathelpbridgedisparitiesandaddressdevelopmentalgaps.AsSecretary-General,IamdedicatedtoprioritizingregionalinitiativesandensuringthatinnovativesolutionsreacheveryMember,particularlythosefacinggreaterdevel-opmentalchallenges.ThepresentreportonthestateoftheclimateinAsiais,inthiscontext,atooltoinformdecision-makingattheregionallevel.

Acomprehensiveanalysisoftheclimatelandscapeformsthecornerstoneofinformeddecision-makingandresponsestrategies.Thisreport,thefourthofitskind,shedslightontheoccurrenceofextremeweathereventsandmonitorskeyclimateindicatorsinAsia.Itcontextualizesthesefindingswithinbroaderclimatetrends.Thereport'sconclusionsaresobering.Manycountriesintheregionexperiencedtheirhottestyearonrecordin2023,alongwithabarrageofextremeconditions,fromdroughtsandheatwavestofloodsandstorms.Climatechangeexacerbatedthefrequencyandseverityofsuchevents,profoundlyimpactingsocieties,economiesand,mostimportantly,humanlives.

WMOremainssteadfastinitscommitmenttomonitoringtheclimatesystemandprovidingauthoritativeinformationtoleadersandthepublicalike.ThroughrobustcollaborationacrosstheUnitedNationsfamilyandwithpartners,weareempoweredtodeliverimpactfulservicesgroundedinreliableinformation.TheGlobalFrameworkforClimateServices,andtheEarlyWarningsforAllinitiative,standastestamentstotheeffectivenessofsuchcollaborativeefforts.Ourpledgeextendstoreachingeverycorneroftheglobe,ensuringthatnoMemberorindividualisleftbehind.

Thespiritofcollaborationandpartnershiphasbeeninstrumentalinthecreationofreportssuchasthisone.lextendmysinceregratitudetoourMembers,sisterUnitedNationsagencies,andalltheexpertsfromboththeAsianregionandaroundtheworldfortheirinvaluablecontributionstothescientificcoordinationandauthorshipofthisreport.

(Prof.CelesteSaulo)Secretary-General

iv

Preface

ter-impactedregionin2023.Floodsandstorms

continuedtocausemostdisaster-relateddeaths

AsiaandthePacificremainedthemostdisas-

andeconomiccosts,astheyaffectthelargest

numberofpeople.Atthesametime,theimpact

ofanincreasingnumberofheatwaveswasalso

moresevere.

Yetagain,in2023,vulnerablecountriesweredis-proportionatelyimpacted.Forexample,TropicalCycloneMocha,thestrongestcycloneintheBayofBengalinthelastdecade,hitBangladeshandMyanmar.Earlywarningandbetterprepared-nesssavedthousandsoflives.Inthisregard,itisimportanttorecognizethekeycontributionthatregionalcooperationmadethroughtheWMO/

ESCAPPanelonTropicalCyclones(PTC)inwarningandforecastingwithhighaccuracyandleadtime.Thisunderscorestheimportanceofregionalapproachesforearlywarningoftransboundaryhazards.

Acriticalgapintheearlywarninginformationchainliesinknowledgeandunderstandingofdisasterrisk.Addressingthisgapisfundamentalforeffectivemulti-hazardearlywarningsystemsandthereforeisakeydeterminantoftheimplementationoftheGlobalExecutiveActionPlanonEarlyWarningsforAllinAsiaandthePacific.

TheEconomicandSocialCommissionforAsiaandthePacific,ESCAP,hasrespondedtothisneedbyconfiguringtheRiskandResiliencePortaltodeepentheknowledgeofrisk,especiallyinhotspotswhereriskisintensifyingundervariouswarmingscenarios.The2023editionof

theESCAPAsia-PacificDisasterReportflaggedthatthereisanarrowwindowforAsiaand

thePacifictoincreaseitsresilienceandprotectitshard-wondevelopmentgainsfromthesocioeconomicimpactsofclimatechange.

Inthiscontext,theStateoftheClimateinAsia2023isanefforttobridgegapsbetweenclimatescienceanddisasterriskthroughevidence-basedpolicyproposals.ESCAPandWMO,workinginpartnership,willcontinuetoinvestinraisingclimateambitionandacceleratingtheimplementationofsoundpolicy,includingbringingearlywarningstoallintheregionsothatnooneisleftbehindasourclimatechangecrisiscontinuestoevolve.

(ArmidaSalsiahAlisjahbana)

Under-Secretary-GeneraloftheUnitedNationsandExecutiveSecretaryofESCAP

1

qdd

ppm

ppmlyear

ppbyear

ppblyear

Globalclimatecontext

Theglobalannualmeannear-surfacetemperaturein2023was1.450.12°℃abovethe1850-1900pre-industrialaverage.Theyear2023wasthewarmestyearonrecordaccordingtosixgloballyaverageddatasets.!Thenineyears2015to2023weretheninewarmestyearsonrecordinalldatasets,2

Atmosphericconcentrationsofthethreemajorgreenhousegasesreachednewrecord-observedhighsin2022,thelatestyearforwhichconsolidatedglobalfiguresareavailable,withlevelsofcarbondioxide(CO₂)at417.90.2partspermillion(ppm),methane(CH)at19232partsperbillion(ppb)andnitrousoxide(N₂O)at335.80.1ppb,respectively150%,264%and124%ofpre-industrial(before1750)levels(Figure1).Real-timedatafromspecificlocations,includingMaunaLoa³(Hawaii,UnitedStatesofAmerica)andKennaook/CapeGrim⁴(Tasmania,Australia)indicatethatlevelsofCO₂,CH,andN,Ocontinuedtoincreasein2023.

Overthepasttwodecades,theoceanwarmingratehasincreased;theoceanheatcontentin2023wasthehighestonrecord.Oceanwarmingandacceleratedlossoficemassfromtheicesheetscontributedtotheriseoftheglobalmeansealevelby4.77mmperyearbetween2014and2023,reachinganewrecordhighin2023.Between1960and2021,theoceanabsorbedabout25%ofannualanthropogenicCO,emittedintotheatmosphere,5andCO₂reactswithseawaterandlowersitspH.Thelimitednumberoflong-termobservationsintheopenoceanhaveshownadeclineinpH,withareductionoftheaverageglobalsurfaceoceanpHof0.017-0.027pHunitsperdecadesincethelate1980s.6Thisprocess,knownasoceanacidification,affectsmanyorganismsandecosystemservices?andthreatensfoodsecuritybyendangeringfisheriesandaquaculture.

(a)

420

(c)Nitrousoxideconcentration

(b)Methaneconcentration

340

1950

1900

N

Carbondioxideconcentration

N

330

M

400

1850

1800

380

各320

1750

360

310

NW

1990

1700

340

300

1650

200020102020

1990200020102020

1990200020102020

(d)Carbondioxidegrowthrate(e)Methanegrowthrate(f)Nitrousoxidegrowthrate

4201.5

3

1.0

2

0.5

0

-5

0.0

199020002010

1990200020102020

2020

1990200020102020

Figure1.Toprow:Monthlygloballyaveragedmolefraction(measureofatmosphericconcentration),

from1984to2022,of(a)CO₂inpartspermillion,(b)CH,inpartsperbillionand(c)N₂Oinpartsperbillion.

Bottomrow:thegrowthratesrepresentingincreasesinsuccessiveannualmeansofmolefractionsfor

(d)CO₂inpartspermillionperyear,(e)CH,inpartsperbilionperyearand(f)N,Oinpartsperbillionperyear.

2

Regionalclimate

ThefollowingsectionsanalysekeyindicatorsofthestateoftheclimateinAsiaduring2023.Onesuchindicatorthatisparticularlyimportant,temperature,isdescribedintermsofanomalies,ordeparturesfromareferenceperiod.Forglobalmeantemperature,theSixthAssessmentReport(AR6)oftheIntergovernmentalPanelonClimateChange(IPCC)°usesthereferenceperiod1850-1900forcalculatinganomaliesinrelationtopre-industriallevels.However,thispre-industrialreferenceperiodcannotbeusedinallregionsasabaselineforcalculatingregionalanomaliesduetoinsufficientdataforcalculatingregion-specificaveragespriorto1900.Instead,the1991-2020climatologicalstandardnormalisusedforcomputinganomaliesintemperatureandotherindicators.RegionaltemperatureanomaliescanalsobeexpressedrelativetotheWMOreferenceperiodforclimatechangeassessment1961-1990.Inthepresentreport,exceptionstotheuseofthesebaselineperiodsforthecalculationofanomalies,wheretheyoccur,areexplicitlynoted.

TEMPERATURE

Variationsinsurfacetemperatureandprecipitationhavealargeimpactonnaturalsystemsandonhumanbeings.ThemeantemperatureoverAsia⁹in2023wasthesecondhighestonrecord(Figure2),0.91℃[0.84°℃-0.96℃]abovethe1991-2020averageand1.87℃[1.81℃-1.92°℃]abovethe1961-1990average.ParticularlyaboveaveragetemperatureswererecordedfromwesternSiberiatocentralAsiaandfromeasternChinatoJapan.JapanandKazakhstaneachhadrecordwarmyears.

Year

Figure2.Annualmeantemperatureanomalies(°C),1900-2023,averagedoverAsia,relativetothe1991-2020average,forthesixglobaltemperaturedatasetsindicatedinthelegend.

Source:HadCRUT5,BerkeleyEarth,NOAAGlobalTempandGISTEMParebasedoninsituobservations.ERA-5andJRA-55arereanalysisdatasets.Fordetailsonthedatasetsandtheplotting,seeTemperaturedata.

3

AveragetemperatureswerebelownormalinpartsoftheinlandIndianPeninsula(Figure3).

Overthelongterm,aclearwarmingtrendhasemergedinAsiainthelatterhalfofthetwentiethcentury(Figures2and4).Inthetworecentsub-periods(1961-1990and1991-2023),Asia,thecontinentwiththelargestlandmassextendingtotheArctic,haswarmedfasterthanthegloballandandoceanaverage.Thisindirectlyreflectsthefactthatthetemperatureincreaseoverlandislargerthanthetemperatureincreaseovertheocean,asstatedintheIPCCAR6report.ThewarmingtrendinAsiain1991-2023wasalmostdoublethewarmingtrendduringthe1961-1990period,andmuchlargerthanthetrendsoftheprevious30-yearperiods(Figure4).

Figure3.Meannear-

surfacetemperature

anomalies(C,differencefromthe1991-2020

average)for2023.Dataarethemedianofsixdatasetsasindicatedinthelegend.SeeDatasetsandmethodsfordetails.

Figure4.Trendsinmean

surfaceairtemperature

forthesixWM0regionsand

theglobalmean(C)over

foursub-periodsusingthesix

datasets.Thecolouredbars

indicatethetrendinthemean

ofthedatasets.Theblack

verticallinesindicatetherange

betweenthelargestandthe

smallesttrendsintheindividual

datasets.

4

PRECIPITATION

Precipitationisakeyclimateparameter,essentialforsocietyintermsofprovidingwaterfordrinkinganddomesticpurposes,agriculture,industryandhydropower.Variationsinprecipitationalsodrivemajorclimateeventssuchasdroughtsandfloods.In2023,substantialprecipitationdeficitsintheregionwereobservedintheTuranLowland(Turkmenistan,Uzbekistan,Kazakhstan);theHinduKush(Afghanistan,Pakistan);theHimalayas;aroundtheGangesandlowercourseoftheBrahmaputraRivers(IndiaandBangladesh);theArakanMountains(Myanmar);andthelowercourseoftheMekongRiver(Figure5and6).Otherregionswhichhadbelow-normalprecipitationweretheregionbetweentheTianShanandGobiAltai(ChinaandMongolia);theWesternSiberianPlain;theStanovoyRange;theArcticCoastbetweentheTaymyrPeninsulaandtheNewSiberianIslands(RussianFederation);aswellasJapanandthesouth-westernpartofChina.

ThelargestabsoluteprecipitationexcesseswereobservedaroundthelowercourseoftheIndusRiver(Pakistan),theTenasserimRange(Myanmar),inKamchatkaandtheKolymaRange(RussianFederation).Unusuallyhighprecipitationtotals(Figure6)werealsonotedinManchuriaandtheNorthernChinaPlain(China);betweentheYamalandTaymyrPeninsulas(RussianFederation);theKazakhSteppe(Kazakhstan);andtheArabianPeninsula(SaudiArabia).

Figure5.Precipitationanomaliesfor2023,expressedasapercentageofthe1991-2020average

Source:GlobalPrecipitationClimatologyCentre(GPCC),

DeutscherWetterdienst,Germany

Figure6.Totalprecipitationin

2023,expressedasaquantileofthe1991-2020referenceperiod,forareasthatwouldhavebeen

inthedriest20%(brown)and

wettest20%(green)ofyears

duringthereferenceperiod,withdarkershadesofbrownandgreenindicatingthedriestandwettest10%,respectively

Source:GPCC,DeutscherWetterdienst,Germany

5

cumulativemassbalance(mw.e.)

CRYOSPHERE

ARCTICSEAICE

Sea-iceextentisakeyindicatorofclimatevariabilityandclimatechangeinthepolarregions.Seaicestronglymodulatessurfaceoceanwavesandtheair-seaexchangesofheat,momentum,moisture,andsoforth,therebyinfluencingtheregionalclimateandtheglobalclimate.Accordingtotheconsensusstatementofthe11thand12thsessionsoftheArcticClimateForum,10.11themaximumArcticiceextentinwinter2023wasreachedon6March2023.Thevalueof14.6millionkm²wasthe5thlowestinthe45-yearsatelliterecord.NegativeiceanomaliesweremostnotableintheWesternandEasternNordicregions.AsmalleranomalywasnotedintheChukchiandBeringRegion.TheminimumArcticiceextentinsummer2023(approximately4.4millionkm²)occurredon17Septemberandwastheeighthlowestannualminimumdailyextentonrecordsince1979(itshouldbenotedthatnumbersandrankingsmayvarymarginallyacrossdifferentdatasetsduetoslightlydifferentcalculationmethodsandthresholds).SignificantnegativeanomaliesweremostprominentintheareasoftheEurasianandCanadianArctic,thoughsomeresidualseaiceremainedinboththeNorthernSeaRouteandthenorthernrouteoftheNorthwestPassageshippinglanesuntilthetimeoffreeze-up.⁷

GLACIERS

Glaciericemassissensitivetochangesinregionaltemperature,precipitation,andsurfaceradiation.Themeltingofglaciersaffectssealevel,regionalwatercyclesandtheoccurrencesoflocalhazardssuchasglacierlakeoutburstfloods(GLOF).TheHigh-MountainAsia(HMA)regionisthehigh-elevationareacentredontheTibetanPlateau;itcontainsthelargestvolumeoficeoutsideofthepolarregions,withglacierscoveringanareaofapproximately100000km².Overthelastseveraldecades,mostoftheseglaciershavebeenretreating,withthealtitudesoftheequilibriumlines(thelowertopographiclimitoftheglaciers)graduallyrising.314Inthepast40years,fourglaciersintheHMAregionwithmorethan30yearsofongoingmass-balancemeasurements(Figure7)haverecordedsignificantmasslosses,withanincreaseintherateofmasslosssincethemid-1990s.Atthesametime,thesefourglaciersshowanoverallweakercumulativemasslossthantheaveragefortheglobalreferenceglaciers(indicatedbyagreylineinFigure7)duringtheperiod1980-2023.AccordingtotheTechnical

Figure7.Cumulativemassbalance(inmetreswaterequivalent(mw.e.))offourreferenceglaciers

intheHighMountainAsiaregionandtheaveragemassbalanceoftheglobalreferenceglaciers

Source:Dataregardingtheglobalreferenceglaciers(grey),LeviyAktruGlacier(green),

Ts.TuyuksuyskiyGlacier(orange)andUrumqiGlacierNo.1(blue)arefromtheWorldGlacierMonitoring

Service(WGMS)(seealsoWGMS.GlobalGlacier

ChangeBulletinNo.5(2020-2021);Zemp,M.;

Gärtner-Roer,l.;Nussbaumer,S.U.etal,Eds.;

ISC(WDS)/IUGG(IACS)/UNEP/UNESCO/WM0,WGMS:Zurich,Switzerland,2023).DataregardingtheXiao

Year

DongkemadiGlacier(purple)arefromtheChineseAcademyofSciences(CAS).

6

Latitude

Longitude

Figure8.Preliminaryestimationsofthe2022-2023massbalanceofglaciersintheHighMountainAsiaregion.Theareaindicatedbygreycontoursis2500metresabovesealevel.

Source:WM0ThirdPoleRegionalClimateCentreNetwork(TPRCC-Network)andWGMS;theoriginalobservationsuponwhichthisfigureisbasedarefromChina,India,Kazakhstan,Kyrgyzstan,Nepal,theRussianFederation,TajikistanandUzbekistan.

SummaryoftheWorkingGroupIcontributiontoIPCCAR6,glaciersoverSouthAsiahavethinned,retreated,andlostmasssincethe1970s(highconfidence),althoughpartialKarakoramglaciershaveeitherslightlygainedmassorareinanapproximatelybalancedstate(mediumconfidence).

Fortheglaciologicalyear2022/2023,20outof22glaciersobservedintheHMAregionshowcontinuednegativemasschanges.Record-breakinghightemperatureanddryconditionsintheEastHimalayaandmostoftheTienShanexacerbatedmasslossformostglaciers.Duringtheperiod2022-2023,UrumqiGlacierNo.1,inEasternTienShan,recordeditssecondmostnegativemassbalance(1.29mw.e.)sincemeasurementsbeganin1959(Figure8).

PERMAFROST

Permafrostissoilthatcontinuouslyremainsbelow0℃fortwoormoreyearsandisadis-tinctivefeatureofhigh-latitudeandhigh-altitudeenvironments.Itischaracterisedbytwokeyvariables,observedtomonitorpermafrostlong-termchangesthatweredefinedasproductsoftheEssentialClimateVariables(ECVs)oftheGlobalClimateObservingSystem(GCOS):meanannualpermafrosttemperatureandthicknessoftheuppermostlayerofseasonallythawing

7

soil-definedasactivelayerthickness(ALT).MonitoringcarriedoutbytheRussianFederal

ServiceforHydrometeorologyandEnvironmentalMonitoring(RosHydroMet)indicatesthat

almostthroughouttheentireterritoryofthepermafrostzoneoftheRussianFederationin

2023,positivetrendsintheALTthicknessremained,closeinvaluetothetrendsseeninthe

1976-2022period,whichindicatesthepersistenceofastabletrendofincreasingtheALT.16The

mostrapidthawingofpermafrostisintheEuropeannorth,thePolarUrals,andthewestern

regionsofWesternSiberia.Relativelymoderateandweakratesofpermafrostthawingare

observedinthecoastalregionsofCentralandNorth-EastSiberia(Figure9).

ThetrendofincreasingALTintheRussianFederationpermafrostzoneisdue,firstofall,tothecontinuingincreaseinairtemperaturesinthehighlatitudesoftheArctic.Intermsofairtemperature,2023wasthesixthwarmestyearintheArcticsince1900.IPCCAR6estimatesthatthawingterrestrialpermafrostwillleadtocarbonrelease(highconfidence),thoughthereislowconfidenceinthetimingandmagnitude.Furthermore,thereportpointsoutthatpermafrostthawing,aswellasglaciermeltandsnowdecline,arealreadyimpactingpopulationsaswellasirrigation,hydropower,watersupply,culturalandotherdomainsdependingonice,snowandpermafrost.

Figure9.Long-termtrendofthethicknessoftheuppermostlayerofseasonallythawingsoil(ALTincmper10years)fortheperiod1976-2023.Permafrostisclassifiedbycoverageincontinuous(90%ofthelandscape),discontinuous(50-90%),andsporadic

(10-50%)zonesandisolatedpatches(10%),dependingontheareacontinuity.

Source:Measurementsfromobservationsites(sitecodesareindicatednexttocirclesonthemap),RussianFederalServicefor

Hydrometeorology(Roshydromet)withintheCircumpolarActiveLayerMonitoringProgram.SeeAnisimov,0.A.;Lavrov,S.A.;

Zhirkov,A.F.etal.PermafrostDataAssimilationandReanalysis:ComputationalSetupandModelValidationforNorthernEuropeanRussiaandEasternSiberia.BussianMeteorologyandHydrology2020,45,269-275.

/10

.3103/S106837392004007X.

SeealsoAnisimov,0.A.PotentialFeedbackofThawingPermafrosttotheGlobalClimateSystemthroughMethaneEmission.

EnvironmentalResearchLetters2007,2,91-98.

/10.1088/1748-9326/2/4/045016

.

8

SNOWCOVER

Snowcoverplaysanimportantroleinthefeedbackmechanismsintheclimatesystem(suchasalbedo,run-off,soilmoistureandvegetation).Hence,itisacrucialvariableformonitoringclimatechange.Inthepast27years,thenorthernhemisphere'sspring(MarchtoMay)snowcoverextent(SCE)''overAsiaexhibitedadecreasingtrendof250000km²perdecade,withnegativeanomalieswithrespecttothe1998-2020long-termaveragedominatingsincethemid-2000s.Inthespringof2023,theSCEinAsiawasabout14.57millionkm²,slightlylessthanthe1998-2020average.Spatially,lower-than-averagesnowextentappearedespeciallyinthenorthernpartofCentralAsiaandNorth-EasternEastAsia.Onthecontrary,positiveSCEanomaliesdominatedfromnorthernEastAsiatocentralNorthAsia(Figure10).IntheHMAregion,SCEwasabovenormalinitswestern,mid-easternregion,andalongthesouthernedge.However,thesouth-eastareaofHMAwasdominatedbynegativeanomalies.

20°E

40°E

NodataWaterIceNosnow-120-60-30-553060120km²

Figure10.Anomaliesofmeansnowcoverextentinthespringof2023(fromMarchtoMay),relativetothe1998-2020average.

Toderivethemonthlysnowcoverextentanomaliesforeachgrid,thenumberofmonthlysnowcoverdayswasdividedbythe

totalnumberofdaysinthatmonthandthenmultipliedbytheareaofthegrid.TheredlinedelimitsthegeographicalareaofWM0RegionalAssociationll(Asia).TheblacklinedelimitstheHighMountainAsiaregion.

Source:InteractiveMultisensorSnowandIceMappingSystemanddatain25kmspatialresolutionfromtheNationalSnowandIce

DataCenter

9

Latitude

edaced/C。

SST(℃)

SST(℃)

thisareaalsohasamajor

SEA-SURFACETEMPERATURE

Sea-surfacetemperature(SST)playsacriticalroleinthecouplingbetweentheoceanandatmosphere,asvariationsinSSTalterthetransferofenergy,momentumandgasesbetweenthesetwocomponentsoftheEarthsystem.18

TheoceanareaofWMORegionalAssociation(RA)ll(Asia)showsanoverallsurfaceoceanwarmingtrendsince1982,atratesofmorethan0.5℃perdecadeintheareasoftheKuroshiocurrentsystem,theArabianSea,theSouthernBarentsSea,theSouthernKaraSea,andthe

South-EasternLaptevSea;thesurfaceoceanwarmingrate

warmingtrendhereismorethanthreetimesfasterthantheglobalof0.16℃0.01℃perdecade.In2023,thearea-averagedSSTanom-

alieswerethewarmestonre-

(a)

Long