利用衛星估算海氣通量及其與颱風強度的關係

Abstract

Information of air-sea turbulent fluxes is critical in air-sea interaction research. Satellite-based flux estimation is currently the most viable way to obtain such flux data over vast oceans at frequent intervals. This work use recently-available advanced remote sensing data sets (including sea surface temperature from TRMM/TMI and AMSR-E, ocean surface wind vectors from QuikSCAT and ADEOS2-SeaWinds) to improve the existing Goddard Satellite Based Surface Turbulent Fluxes version 2 scheme. Thus, spatial resolution is improved from 1∘by 1∘to 0.25 ∘by 0.25 ∘and temporal resolution is improved from daily to 2-4 times daily. Air-sea surface fluxes of sensible and latent heat provide energy to tropical cyclone; they are vital role in typhoon-ocean interaction research. To obtain such flux information under cyclone’s wind condition, the latest high-wind transfer coefficients from field and laboratory experiments are used. Also, impact of typhoon’s self-induced SST cooling is incorporated in the flux estimation to obtain more realistic fluxes. With the high-wind flux estimations, all 40 tropical cyclones, including depression, tropical storm, and typhoons during July to September from 2003-2005 are studied. Wind shear is also estimated and jointly analyzed with the flux data to study typhoon’s intensity change. It is found that typically typhoons can intensify under wind shear value of less than 10 ms-1. When vertical wind shear is small and with sufficient flux supply, typhoons may rapidly intensify. Insufficient flux supply from ocean or moving to high wind shear region or landfall are the causes for typhoon’s intensity decay.