资源描述：
《Optimal estimation of the present‐day global methane budget前全球甲烷收支的最优估计》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、GLOBALBIOGEOCHEMICALCYCLES,VOL.24,GB4024,doi:10.1029/2009GB003661,2010Optimalestimationofthepresent‐dayglobalmethanebudget1,211LisaNeef,MichielvanWeele,andPetervanVelthovenReceived27August2009;revised13August2010;accepted30August2010;published8December2010
2、.1312[1]HistoricalobservationsoftheC/CratioofatmosphericCH4areusedtoconstrainthepresent‐daymethanebudgetusingoptimalestimation.Threemethaneemission13scenarioswithbasisintherecentliteratureareevaluatedagainsthistoricalCH4observations,consideringalluncertain
3、tiestogether.Weestimatethatpresent‐daymethaneemissionsarecomposedof64%–76%biogenic,19%–30%fossil,and4%–6%pyrogenicsources.Itisfoundthat,barringanychangesintheisotopicsignaturesofsourcesandsink1312processes,satisfyingtheC/Crecordrequiresestimatesofpresent‐d
4、ayanthropogenicfuel‐relatedemissionsthatareonthehighendoftheassumeduncertainties,evenwhenasignificantgeologicalsourceisincluded.Extendingpresent‐dayresultstothetimeoftheLastGlacialMaximum(LGM),emissionsfromwetlandsareimpliedtobe40%–62%ofthepresent‐dayvalue
5、,thehighernumberbeingvalidonlyforascenariowithstrong(∼30Tg/a)geologicalemissionsandroughly20%greaterbiomassburningemissionsatLGMrelativetothepresent‐day.Citation:Neef,L.,M.vanWeele,andP.vanVelthoven(2010),Optimalestimationofthepresent‐dayglobalmethanebudge
6、t,GlobalBiogeochem.Cycles,24,GB4024,doi:10.1029/2009GB003661.1.Introductionarethereforeneededtodistinguishsourcetypesfromoneanother.[2]Despitetheimportantroleofmethane(CH4)incli-[3]Additionalconstraintsexistinthedistinct“signatures”mateforcing,themagnitude
7、sofitssourcesandsinksarestillofcarbonandhydrogenisotopesthatcharacterizedifferentpoorlyquantified[Denmanetal.,2007].AnthropogenicCH4sources.TheobservedratioofD/HinatmosphericCH4emissionsarediverseandincludecoalmining,naturalgashasbeenusedbyWhiticarandSchae
8、fer[2009],Sowersuse,agriculture,andwastetreatment.NaturalsourcesofCH4,[2010],andMischleretal.[2010]toestimatetherelativeespeciallywetlandsandgeologicalseepage[Etiopeetal.,strengthofthermogenicclathrateemissio
