Arctic Mechanisms of Interaction between the Surface and Atmosphere (AMISA) IPY Airborne Data Set
Abstract
The Arctic Mechanisms of Interaction Between the Surface and Atmosphere (AMISA) campaign is an International Polar year (IPY) project conducted in conjunction with a related ship-based IPY project, the Arctic Summer Cloud-Ocean Study (ASCOS). Understanding the top-side atmospheric and sea ice radiative processes contributing to Arctic sea ice reduction is the primary goal of AMISA. This poster describes the field activities and status of AMISA data processing studies at the end of the final grant year. Tropospheric synoptic and mesoscale disturbances over the Arctic Ocean force large, transitory changes in the structure of the Arctic boundary layer (ABL) and its surface energy budget (SEB). These changes determine the near-surface air temperature and drive the thermodynamic and mass balance of sea ice. The thermal, kinematic, and cloud features associated with these disturbances modify the kinematic and thermodynamic structure of the ABL through both turbulent and radiative fluxes and changes in ABL clouds. These changes, in turn, subsequently affect the SEB of the pack ice. Accordingly, processes linking atmospheric synoptic and mesoscale disturbances to ABL structure and SEB during the seasonal transition periods were the primary observational objectives of AMISA. To achieve these objectives high resolution observations of Arctic sea ice cover and type along with meteorological conditions representative of significant mesoscale processes were obtained during five sorties over polar sea ice as part of the 23-day AMISA deployment in August 2008 using the NASA DC-8 aircraft based out of Kiruna, Sweden. Measurements of ABL cloud and moisture content and identification of summertime meltponds (which produce different radiative and turbulent fluxes) and leads were included. DC-8 data includes high resolution microwave imagery of sea ice using the Polarimetric Scanning Radiometer (PSR/A) system, video data used for ice/lead/meltpond discrimination, and direct sampling of radiance, thermodynamic and cloud variables over wide areas using in situ cloud probes, dropsondes, and nadir and zenith staring microwave radiometric measurements (including temperature profiling). The DC-8 measurements occurred over and in the vicinity of the Swedish ice breaker Oden fielded under the ASCOS project. The AMISA observations are currently being calibrated and studied to understand the impact of mesoscale, turbulent, and aerosol-driven atmospheric processes on surface-energy transition-to-freezeup conditions. The passive microwave imagery is are also being used to improve the NASA AMSR-E sea ice algorithm during summertime Arctic conditions, specifically, to understand the effects of clouds on AMSR-E sea ice signatures.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A11K0197G
- Keywords:
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- 0321 ATMOSPHERIC COMPOSITION AND STRUCTURE / Cloud/radiation interaction;
- 0350 ATMOSPHERIC COMPOSITION AND STRUCTURE / Pressure;
- density;
- and temperature;
- 0394 ATMOSPHERIC COMPOSITION AND STRUCTURE / Instruments and techniques;
- 0750 CRYOSPHERE / Sea ice