INLAND WATERS REPRESENT GREATER THAN 3% OF THE TOTAL CONTINENTAL SURFACE OF THE PAN-ARCTIC WITH DENSITIES OF SURFACE WATERS EXCEEDING 10% IN SHIELD BEDROCK AND LOW SLOPE DELTAIC ENVIRONMENTS DOMINATED BY LAKES. CARBON EMISSIONS FROM HIGH LATITUDE LAKES CAN EXCEED 340 TG C YR-1 AND RELEASE UPWARDS OF 16.5 TG-C-CH4 YR-1. THIS REPRESENTS ONE OF THE LARGEST NATURAL SOURCES OF ATMOSPHERIC METHANE FROM THE ARCTIC-BOREAL REGION. SURFACE WATER SIGNIFICANTLY IMPACTS LANDSCAPE-SCALE ESTIMATES OF CARBON EMISSIONS. FIELD STUDIES SHOW THAT THE INPUT OF CARBON TO LAKES REQUIRES HYDROLOGIC CONNECTIVITY BOTH ACROSS THE SURFACE OR WITHIN THE SUBSURFACE. SIGNIFICANT UNCERTAINTY EXISTS REGARDING THE EXCHANGE OF WATER IN LOW SLOPE/LOW PRECIPITATION ENVIRONMENTS. THESE CHARACTERISTICS MAKE DEFINING WHERE UPLANDS AND WETLANDS END AND LAKES BEGIN DIFFICULT AND HIGHLIGHT AN OFTEN OVERLOOKED COMPONENT OF ECOSYSTEM CARBON FLOWS THE TERRESTRIAL-AQUATIC INTERFACE. CURRENTLY THE MAGNITUDE AND EXTENT OF ARCTIC-BOREAL SEASONALLY INUNDATED LAND REMAINS UNKNOWN AND WE HYPOTHESIZE THAT THE REGION OF REGULARLY INUNDATED SOILS ARE HOTSPOTS FOR THE CYCLING OF CARBON AND ARE HIGHLY VULNERABLE TO CHANGE. THE 2017 NASA ARCTIC-BOREAL VULNERABILITY EXPERIMENT (ABOVE) AIRBORNE CAMPAIGNS (AAC) ACQUIRED AIRBORNE REMOTE SENSING DATA CROSSING BROAD ENVIRONMENTAL GRADIENTS. UAVSAR AND AIRMOSS ARE BOTH CAPABLE OF MEASURING INUNDATION EXTENT UNDER VEGETATION. AVIRIS-NG CAN QUANTIFY VEGETATION EXTENT AND TYPE. AIRSWOT MEASURES WATER SURFACE ELEVATION (WITH RADAR INTERFEROMETRY) AND AQUATIC VEGETATION BOUNDARIES (WITH AN INFRARED CAMERA) SIMULTANEOUSLY. FINALLY LVIS MEASURES WATER AND LAND ELEVATION AND EVIDENCE OF EMERGENT AQUATIC PLANTS. THESE PREVIOUSLY ACQUIRED DATASETS OFFER A UNIQUE OPPORTUNITY TO STUDY SEASONAL ARCTIC-BOREAL INUNDATION PATTERNS THROUGH VEGETATION AND LINK THESE PATTERNS TO THE CYCLING OF CARBON. HERE WE PROPOSE TO QUANTIFY INUNDATION EXTENT ACROSS FOUR IMPORTANT CLASSES OF HYDROLOGIC CONNECTIVITY REPRESENTATIVE OF THE ABOVE DOMAIN: OPEN WATER PERMANENT INUNDATION TRANSIENT INUNDATION AND DRY UPLANDS. USING ABOVE AIRBORNE REMOTE SENSING DATA WE WILL MAP THESE CLASSES ACROSS A HYDROLOGICAL GRADIENT OF LANDSCAPES: FLUVIAL-CONNECTED LOWLAND (THE PEACE-ATHABASCA DELTA CANADA); FLUVIAL-DISCONNECTED LOWLAND (YUKON FLATS ALASKA) AND BEDROCK CONTROLLED (YELLOWKNIFE-DARING LAKE CANADA). WE WILL PRODUCE VALIDATED MAP PRODUCTS OF VEGETATION CLASSIFICATION AND INUNDATION EXTENT AS WELL AS DIRECT ESTIMATES OF CARBON CONCENTRATIONS FLUX AND CARBON SOURCE. WITH ADDITIONAL SUPPORT FROM THE U.S. GEOLOGICAL SURVEY WE WILL CONDUCT A SERIES OF COMPREHENSIVE FIELD CAMPAIGNS TO QUANTIFY THE VARIABILITY IN CARBON FLUX AMONG THESE DIFFERENT CLASSES AND LANDSCAPES WITH THE GOAL OF IDENTIFYING THE IMPORTANCE OF INUNDATED LANDS IN THE NET CARBON BALANCE OF ARCTIC-BOREAL AQUATIC ENVIRONMENTS. THE PROPOSED RESEARCH WILL ADDRESS TIER 2 SCIENCE QUESTIONS FOCUSING ON THE INTERSECTION OF CHANGING HYDROLOGY SPECIES COMPOSITION AND CARBON CYCLING ACROSS THE TERRESTRIAL TO AQUATIC DOMAINS. THIS RESEARCH WILL PROMOTE INTER-AGENCY COLLABORATIONS BETWEEN THE U.S. GEOLOGICAL SURVEY AND U.S. FISH AND WILDLIFE AS HIGHLIGHTED IN THE A.4 TE AMENDMENT 10 (3.2) AS WELL AS ENGAGE WITH ENVIRONMENT AND CLIMATE CHANGE CANADA THE GOVERNMENT OF THE NORTHWEST TERRITORIES AND SPECIALISTS AT THE UNIVERSITY OF WATERLOO ONTARIO CANADA. THIS RESEARCH BRINGS TOGETHER A TEAM OF CARBON BIOGEOCHEMISTS (BUTMAN STRIEGL SPENCER WICKLAND) WITH PHYSICAL GEOGRAPHERS (SMITH PAVELSKY) SPECIALIZED IN SURFACE WATER DYNAMICS. THIS WORK WILL SUPPORT 1 POST-DOCTORAL SCIENTIST AND TWO PHD STUDENTS AND WILL BENEFIT FROM STRONG COLLABORATIVE SUPPORT FOR AN ADDITIONAL POST-DOCTORAL SCIENTIST (USGS). THESE EFFORTS WILL PRODUCT NEW CAPACITY FOR CONDUCTING LARGE SPATIAL DATA ANALYSIS WITH THE SKILLS TO LINK THESE DATA TO FIELD BASED MEASURES OF CARBON CYCLING.