CONSTRAINING AND PROJECTING WETLAND METHANE EMISSIONS IN THE NORTHERN UNITED STATES

WE PROPOSE TO: DEVELOP NEW CONSTRAINTS ON NORTHERN US WETLAND METHANE FLUXES; ADVANCE UNDERSTANDING OF THE EVOLVING ENVIRONMENTAL FACTORS DRIVING EMISSIONS; AND IMPROVE PREDICTIONS OF EMISSION RESPONSE TO CLIMATE CHANGE. METHANE IS THE SECOND MOSTIMPORTANT ANTHROPOGENIC GREENHOUSE GAS AND WETLANDS ARE ITS LARGEST AND MOST UNCERTAIN GLOBAL SOURCE. THE UPPER MIDWEST IS ONE OF THE LARGEST WETLAND-RICH AREAS IN THE US. CONSTRAINING AND PREDICTING EMISSIONS FROM THIS AREA IS CRUCIAL TO CLOSING THE US METHANE BUDGET AND FOR TOP-DOWN ANALYSES TO SEPARATE ANTHROPOGENIC FROM NATURAL METHANE EMISSIONS AND IN TURN INFORM POLICY. RESEARCH WILL ADDRESS THE FOLLOWING QUESTIONS: A) WHAT IS THE MAGNITUDE OF WETLAND METHANE FLUXES IN THE UPPER MIDWEST? HOW DO EMISSIONS VARY SEASONALLY AND INTER-ANNUALLY? B) HOW WELL CAN CURRENT MODELS REPRESENT THESE WETLAND METHANE FLUXES AND THEIR VARIABILITY? C) WHAT IS THE CONTRIBUTION OF REGIONAL WETLANDS TO THE TOTAL METHANE BUDGET IN THE UPPER MIDWEST AND FOR THE US AS A WHOLE? D) HOW DO REGIONAL WETLAND METHANE EMISSIONS DEPEND ON ENVIRONMENTAL DRIVERS? WHAT ARE THE IMPLICATIONS FOR FUTURE EMISSIONS? WE PROPOSE 4 TASKS TO ADDRESS THESE QUESTIONS. 1) EVALUATE SATELLITE (GOSAT) OBSERVATIONS FOR THIS AREA BASED ON NASA-SUPPORTED AIRCRAFT MEASUREMENTS. 2) INVERSE MODELING OF WETLAND METHANE EMISSIONS IN THE NORTHERN US AND SOUTHERN CANADA BASED ON GOSAT WITH INDEPENDENT VALIDATION USING EDDY FLUX MEASUREMENTS. 3) QUANTIFY THE MAGNITUDE SEASONALITY AND INTER-ANNUAL VARIABILITY OF REGIONAL WETLAND FLUXES AND THEIR IMPORTANCE FOR THE UPPER MIDWEST AND US METHANE BUDGETS. 4) DEVELOP NEW PARAMETERIZATIONS FOR REGIONAL WETLAND FLUXES THAT CAPTURE OBSERVED ENVIRONMENTAL DEPENDENCIES AND APPLY THEM TO GENERATE FUTURE PROJECTIONS AND DIAGNOSE THE LIKELY RANGE OF FUTURE WETLAND METHANE EMISSIONS FROM THIS KEY AREA. THIS PROJECT ADDRESSES THE GOALS OF THIS NASA SOLICITATION IN THE AREAS OF 'CLIMATE VARIABILITY AND CHANGE' 'CARBON CYCLE AND ECOSYSTEMS' AND 'ATMOSPHERIC COMPOSITION'