A study on retrieval algorithms in oceanic passive microwave remote sensing using 1.4 GHz and 10.7 GHz bands

To retrieve sea-surface salinity (SSS) from radiometer data at 1.4 GHz, auxiliary data of sea-surface temperature (SST), surface roughness and meteorological variables are needed. The authors study oceanic passive polarimetric microwave remote sensing using 1.4 GHz and 10.7 GHz bands. A set of algorithms are developed for 1.4 GHz and 10.7 GHz microwave polarimetric radiometer at 50° incidence angle to retrieve wind vector, as well as other geophysical parameters, such as SSS, SST, atmospheric volumes of water vapor and liquid water. Idealized retrievals are conducted using 2 324 simulated brightness temperatures of full Stokes parameters at 1.4 GHz and 10.7 GHz. Results indicate that SSS, SST, sea-surface wind speed, direction, atmospheric volumes of water vapor and liquid water can be inversed at the same time. This suggests an alternative way for SSS remote sensing.

THE RELATIONSHIP BETWEEN THE TAIWAN WARM CURRENT AND TSUSHIMA WARM CURRENT

The Taiwan Warm Current （TWC） and the Tsushima Warm Current （TSWC） flow northward over the shelf in the East China Sea （ECS）, which some previous studies regard as a Taiwan-Tsushima Warm Current （TTWC） System. But the roles of the TWC and TSWC in the formation of the TTWC system have not been clarified. This article will show that the TSWC is more important in the TTWC system. Using a three-dimensional baroclinic model, we conducted several numerical experiments to reveal the dynamic relationship between the TWC and TSWC. The results show that the TWC has little effect on the TSWC, while the TSWC has a significant effect on the TWC. A source-sink driven mechanism along isobaths may be used to explain this phenomenon The perennial northward flow through the Tsushima Strait pumps the response over the northern shelf in the ECS that gives rise to the TWC. Although the TSWC is located at the ＂downstream＂ region, it could induce about 0.5 Sv to TWC in annual mean values.

INTERANNUAL VARIABILITY OF KUROSHIO CURRENT AND ITS EFFECT ON THE NEARSHORE BRANCH IN JAPAN/EAST SEA

Based on the Hybrid Coordinate Ocean Model （HYCOM）, this article presents simulations of the three-dimensional dynamic and thermal structure of the North Pacific Ocean （NPO） in the time domain from January 1991 to December 2000. The baroclinic current field and its interannual variability in Northwest Pacific Ocean （NWPO）, especially, the Kuroshio Current （KC） and the Japan/East Sea （JES） are analyzed and discussed. The results show that the HYCOM covers a complete dynamic and thermo process with adequate representations of the eddy fields and variability in main spatial and temporal scales. The model is used to simulatethe strong interanual variability of the KC, which may affect the strength of the eastern bifurcation of the Tsushima Warm Current （TSWC）, named the Nearshore Branch （NB） in the JES. When the KC is strong and its axis is close to the Japan Island, the TSWC and its bifurcations in the JES would intensify accordingly. Our results confirm once again the hypothesis of Yang et al. that the KC determines the annual mean NB in the JES via the ＂island integral constraint＂. This article further extends this hypothesis to study the KC role in the NB on a time dependent scale.