WE PROPOSE TO CONTINUE THE LONGSTANDING COLLABORATION BETWEEN THE SHINDELL RESEARCH GROUP AT DUKE UNIVERSITY AND NASA GISS ON ATMOSPHERIC COMPOSITION-CLIMATE INTERACTIONS. THE PROJECT BRINGS TOGETHER THE EXPERTISE OF THE SHINDELL GROUP IN ATMOSPHERIC CHEMISTRY AND AEROSOLS WITH THAT OF GISS IN COUPLED CLIMATE MODELING AND BUILDS ON THEIR PARTNERSHIP IN THE ANALYSIS OF THE CLIMATE RESPONSE TO VARIOUS FORCING AGENTS (INCLUDING INHOMOGENEOUS ONES) BY MEMBERS OF BOTH TEAMS (E.G. SHINDELL SCHMIDT MILLER FALUVEGI). THE RESEARCH IS DIRECTED AT (1) COORDINATING COMPOSITION MODELING TO IMPROVE THE CURRENT CAPABILITIES AT GISS AND MAINTAIN THOSE AS THE REST OF THE CLIMATE MODEL CONTINUES TO DEVELOP FOR EXAMPLE IN THE HIGHER RESOLUTION CUBED-SPHERE VERSIONS (2) UTILIZING INCREASED CAPABILITIES TO EVALUATE KEY METRICS OF MODEL REALISM RELATED TO INHOMOGENEOUS FORCERS THAT HAVE BEEN DEVELOPED AT DUKE TO GUIDE MODEL IMPROVEMENT EFFORTS (3) USING OUTPUT FROM GISS (AND OTHER CMIP6) MODEL RUNS TO EVALUATE THE IMPACT OF COMBINED AIR POLLUTION AND CLIMATE CHANGE IN THE RECENT PAST IN THE SSPS AND FOR ASSESSMENTS SPONSORED BY UN ENVIRONMENT AND (4) APPLYING THE COMPOSITION-CLIMATE MODEL TO BETTER UNDERSTAND THE RESPONSE OF THE CLIMATE SYSTEM TO THE INHOMOGENEOUSLY DISTRIBUTED FORCINGS.