The Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE): Results from 2011 Engineering Test Flights

The carbon balance of Arctic ecosystems is not known with confidence since fundamental elements of the complex Arctic biological-climatologic-hydrologic system are poorly quantified. CARVE - The Carbon in Arctic Reservoirs Vulnerability Experiment - will address this key gap in science knowledge by: 1) Directly testing hypotheses attributing the mobilization of vulnerable Arctic carbon reservoirs to climate warming; 2) Delivering the first direct measurements and detailed maps of CO₂ and CH₄ sources on regional scales in the critical Arctic ecozone; and 3) Demonstrating new remote sensing and modeling capabilities to quantify feedbacks between carbon fluxes and carbon cycle-climate processes in the Arctic. CARVE measurements and integrated science data will provide unprecedented experimental insights into Arctic carbon cycling and its response to climate change. CARVE employs a robust, flexible strategy to reconcile Arctic carbon fluxes estimated from atmospheric concentrations of CO₂ and CH₄ (top-down approach) with carbon fluxes estimated from coincident measurements of surface state controls (bottom-up approach). The CARVE Science Operations involve deployments in Alaska during the spring, summer, and fall each year from 2012-2014. CARVE flight plans sample multiple permafrost domains and ecosystems, and deliver detailed observations over ground-based measurement sites, fires, and burn-recovery chronosequences. CARVE flies aboard the De Havilland DHC-6 Twin Otter. The science payload consists of: JPL's Passive Active L-band System (PALS) to deliver the measurements of soil moisture, freeze/thaw state, inundation state, and surface temperature; an airborne Fourier Transform Spectrometer (FTS) to deliver total atmospheric column measurements of CO₂ and CH₄, and CO; and (3) an In Situ Gas Analyzer (ISGA) to deliver continuous measurements of CO₂ and CH₄, and CO, calibration standards, and whole air flask samples for point measurements of over 50 trace gases. Aircraft measurements are augmented by ground site measurements at key locations spanning a range of ecosystem/permafrost domain combinations. Engineering test flights in Colorado, Alaska and Oklahoma during March - June 2011 demonstrated performance readiness. CARVE science operations are scheduled to begin in March 2012.