AIRBORNE SEASONAL SURVEY OF CO2 AND CH4 ACROSS ABOVE DOMAIN LARGE CHANGES IN SURFACE AIR TEMPERATURE SEA ICE COVER AND PERMAFROST IN THE ARCTIC BOREAL ECOSYSTEMS (ABE) ARE LIKELY TO HAVE SIGNIFICANT IMPACT ON THE CRITICAL ECOSYSTEM SERVICES AND THE HUMAN SOCIETIES THAT ARE DEPENDENT ON THE ABE. IN ORDER TO PREDICT THE OUTCOME OF CONTINUED CHANGE TO THE CLIMATE SYSTEM IN THE ABE IT IS NECESSARY TO UNDERSTAND THE VULNERABILITIES OF THE UNDERLYING ABE ECOSYSTEMS BY UNDERSTANDING WHAT PROCESSES DRIVE BOTH SPATIAL VARIABILITY AND INTERANNUAL VARIABILITY. THE PROPOSED STUDY ENTITLED AIRBORNE SEASONAL SURVEY OF CO2 AND CH4 ACROSS THE ABOVE DOMAIN FOCUSES ON IMPROVING OUR UNDERSTANDING AND PREDICTIVE CAPABILITIES FOR MODELING THE LAND-ATMOSPHERIC EXCHANGE OF CO2 AND CH4 TO BETTER UNDERSTAND THE FEEDBACKS THAT THESE GREENHOUSE GASES WILL HAVE ON THE ABE. WE WILL PERFORM THIS TASK IN THE FOLLOWING WAY: 1. AIRBORNE MEASUREMENTS A MULTI-ECOSYSTEM/SEASONAL AIRCRAFT SURVEY OF THE ABOVE STUDY AREA IS PROPOSED WHICH WILL PROVIDE BOTH IN SITU AND FLASK MEASUREMENTS OVER SEVEN ECOSYSTEMS DURING SIX SURVEYS BETWEEN APRIL AND NOVEMBER OF THE 2017 FIELD SEASON. THE IN SITU MEASUREMENTS WILL INCLUDE CO2 CH4 CO O3 H2O TEMPERATURE AND WIND; THE FLASK MEASUREMENTS WILL INCLUDE MORE THAN 50 DIFFERENT SPECIES INCLUDING CO2 CH4 CO SF6 AND A VARIETY OF HYDROCARBONS HALOCARBONS AND ISOTOPES OF CARBON. 2. ANALYSIS OF AIRBORNE MEASUREMENTS THE DATA COLLECTED DURING THE MULTI-ECOSYSTEM/SEASONAL AIRCRAFT SURVEY WILL BE COMBINED WITH TWO INTENSIVE AIRBORNE STUDIES OF THE NORTH SLOPE IN 2015 AND 2016; CARBON IN ARCTIC RESERVOIRS VULNERABILITY EXPERIMENT (CARVE); CARVE-CAN AND NOAA AIRCRAFT SAMPLING SITES TO SUMMARIZE THE FINDINGS OF ALL OF THESE FLIGHT MISSIONS AND UNDERSTAND THEIR UNIQUE CONTRIBUTION. 3. INVERSE MODELING ANALYSIS LEVERAGING GROUND-BASED DATA COLLECTED FROM THE ABE GATHERED AS PART OF THE PHASE 1 ABOVE PROJECT OF CO-PI (JPL) AND A PRE-ABOVE PROJECT LED BY HARVARD WE WILL CREATE A SPATIALLY EXPLICIT ESTIMATE OF THE CO2 AND CH4 FLUXES FROM 2012-2017 FOR THE ABE. THE MULTI-YEAR PRODUCT OVER THE ALASKAN DOMAIN WILL PROVIDE A BASELINE ESTIMATE OF INTERANNUAL VARIABILITY AND SPATIAL VARIABILITY THROUGHOUT THE ABOVE DOMAIN. 4. EVALUATION OF OCO-2 RETRIEVALS. DURING THE SUMMER MONTHS THE ORBITING CARBON OBSERVATORY-2 (OCO-2) OFFERS VALUABLE DATA THAT WILL AUGMENT THE AVAILABLE CO2 MEASUREMENTS MADE FROM GROUND AND AIRCRAFT SITES AS WELL AS ADD SOLAR-INDUCED CHLOROPHYLL FLUORESCENCE DATA THAT HAS HAD A DRAMATIC INFLUENCE ON THE PRIOR MODEL THAT WE WILL BE USING FOR OUR INVERSE MODELING ANALYSIS. OUR RESULTS WILL SIGNIFICANTLY REDUCE UNCERTAINTIES IN ESTIMATES OF THE CURRENT CARBON BALANCE OF ABOVE ABE AND MODEL PROJECTIONS AS THE CLIMATE CONTINUES TO CHANGE. OUR RESEARCH: 1) PROVIDES A BASELINE RECORD OF ATMOSPHERIC OBSERVATIONS CARBON FLUX PATTERNS AND MAGNITUDES THAT CAN BE USED TO DOCUMENT CHANGE IN THE FUTURE 2) IMPROVES OUR ABILITY TO ESTIMATE REGIONAL-SCALE CARBON FLUXES AND THEIR DRIVERS AND 3) INFORMS DECISION MAKING AND ECOSYSTEM SERVICES MANAGEMENT THROUGH REDUCED UNCERTAINTY IN PROJECTIONS OF LONGTERM CHANGE IN ABE CARBON BALANCE. THE STUDY SEEKS TO ANSWER THE TIER 2 SCIENCE QUESTIONS DEFINED IN THE ABOVE CONCISE EXPERIMENT PLAN: "HOW ARE THE MAGNITUDES FATES AND LAND-ATMOSPHERE EXCHANGES OF CARBON POOLS RESPONDING TO ENVIRONMENTAL CHANGE AND WHAT ARE THE BIOGEOCHEMICAL MECHANISMS DRIVING THESE CHANGES?