Improvements to TOVS retrievals over sea ice and applications to estimating Arctic energy fluxes

摘要: Modeling studies suggest that polar regions play a major role in modulating the Earth's climate and they may be more sensitive than lower latitudes to change. Until recently, however, data from meteorological stations poleward of 70 degs have been sparse, consequently, our understanding air-sea-ice interaction processes is relatively poor. Satellite-borne sensors now offer promising opportunity observe ultimately improve parameterizations energy transfer models. This study focuses on application TIROS-N operational vertical sounder (TOVS) sea-ice-covered nonmelt season. TOVS radiances are processed with improved initialization inversion ('3I') algorithm, providng estimates layer-average temperature moisture, cloud conditions, surface characteristics at horizontal resolution approximately 100 km x km. Although has flown continuously polar-orbiting satellites since 1978, its potential not realized high because quality retrievals often significantly over sea ice snow surfaces. The recent availability three Arctic sets provided an validate retrievals: first Coordinated Eastern Experiment (CEAREX) winter 1988/1989, second LeadEx field program spring 1992, third Russian drifting stations. Comparisons these reveal deficiencies during cold season; e.g., 5 15 K too warm, microwave emissivity 15% low large view angles, clear/cloudy scenes sometimes misidentified, low-level inversions captured. In this study, methods reduce errors investigated. Improvements retrieval reduced rms 7 3 K; correction microwaves (50 GHz) brightness temperatures for angle dependence allows type (open water versus ice) determined; modifications clear/cloud tests detection ice, especially where it inhomogeneous; resulted successful diagnoses stratification. Applications budget encouraging. Preliminary calculations air-ice stress vectors, 10-m wind speed, advection heat moisture presented.