THE FUTURE DISTRIBUTIONS OF STRATOSPHERIC WATER VAPOR AND OZONE ARE STRONGLY AFFECTED BY GLOBAL WARMING DUE TO INCREASES IN GREENHOUSE GASES. CHANGES IN STRATOSPHERIC WATER VAPOR AND OZONE IN TURN AFFECT CLIMATE RESPONSE TO GREENHOUSE GAS FORCING. STRATOSPHERIC OZONE CHANGE NOT ONLY DIRECTLY AFFECTS SURFACE WARMING BUT ALSO MODIFIES THE STRATOSPHERIC WATER VAPOR FEEDBACK BY MODULATING TROPICAL TROPOPAUSE TEMPERATURE. THE COMBINED STRATOSPHERIC OZONE FEEDBACK AND THE MODIFIED STRATOSPHERIC WATER VAPOR FEEDBACK CAUSE LESS WARMING OF GLOBAL SURFACE TEMPERATURE. THE STRENGTH OF THE STRATOSPHERIC CHEMICAL FEEDBACK HOWEVER IS HIGHLY UNCERTAIN. BECAUSE THE MAGNITUDE OF FUTURE GLOBAL WARMING STRONGLY DEPENDS ON CLIMATE FEEDBACKS IT IS CRITICAL TO IMPROVE THE UNDERSTANDING OF THE STRATOSPHERIC CHEMICAL FEEDBACK AND ITS IMPACT ON GLOBAL WARMING.WE PROPOSE TO QUANTIFY AND CONSTRAIN THE STRATOSPHERIC WATER VAPOR AND OZONE RESPONSES AND FEEDBACKS TO GLOBAL WARMING USING THE COUPLED NASA GODDARD EARTH SYSTEM MODEL VERSION 5 (GEOS-5) AND NASA SATELLITE OBSERVATIONS. WE WILL QUANTIFY THE STRATOSPHERIC CHEMICAL FEEDBACK IN GEOS-5 BY CONDUCTING QUADRUPLING CO2 SIMULATIONS. SENSITIVITY SIMULATIONS WILL BE PERFORMED TO SEPARATE THE ROLES OF STRATOSPHERIC OZONE AND WATER VAPOR IN THE STRATOSPHERIC CHEMICAL FEEDBACK. WE WILL QUANTIFY THE DRIVERS OF STRATOSPHERIC WATER VAPOR AND OZONE RESPONSES TO GLOBAL WARMING AND CHARACTERIZE THEIR LINKS. OBSERVED DECADAL VARIATIONS IN STRATOSPHERIC WATER VAPOR AND SURFACE WARMING WILL BE USED TO EVALUATE AND CONSTRAIN THE SIMULATED STRATOSPHERIC OZONE AND WATER VAPOR CHANGES AND THEIR IMPACT ON GLOBAL WARMING.OUR PROPOSAL IS DIRECTLY RELATED TO THE ACAMP RESEARCH ELEMENT OF CHEMISTRY/CLIMATE INTERACTIONS. OUR PROPOSED RESEARCH FALLS WITH THE FOCUS AREA OF THE ACMAP PROGRAM ON UNDERSTANDING HOW ATMOSPHERIC COMPOSITIONS RESPOND TO AND AFFECT GLOBAL ENVIRONMENT CHANGE.