The Thin Ice Clouds in Far IR Experiment (TICFIRE): A Potential Canadian Contribution to NASA A-CCP

Abstract:

Processes and feedback mechanisms involving clouds and aerosols represent one of the largest sources of uncertainty in our understanding of Earth’s climate system. Through their modulation of radiation, precipitation, and atmospheric composition, clouds dominate the Earths’ energy and water budgets. Their high variability in spatiotemporal and optical properties, especially for the thin ice clouds, makes them difficult to observe, to characterize and to model. Because radiative transfer is sensitive to particles whose sizes are comparable to the radiation wavelength, 10-100 µm ice crystals interact much with FIR. Observations of radiation in the FIR are sensitive to crystal size, optical depth (water content), liquid-ice mixture, and water vapour concentration in the low limit. In recent years, we have successfully tested the FIR Radiometer (FIRR), a prototype of the TICFIRE, through airborne and ground-based campaigns. Verification against the E-AERI at the PEARL facility in Eureka (80^oN), at the Iqaluit supersite (YOPP) and theoretical calculations have shown the performance and the reliability of FIRR/TICFIRE. Based on a strong radiometric heritage, narrow band FIR data are readily assimilated into operational weather forecasting systems. Joint with sister instruments ALI and SHOW for aerosol and water vapour, the tandem offers a strong synergy on aerosol, water, cloud, precipitation, and radiation interaction in the cold regions of the globe and UTLS. These instruments are the Canadian candidates for potential contributions to the NASA’s decadal program for the A-CCP mission.