利用2004年5-10月NOAA/AVHRR的SST资料和MODIS(SeaWiFS)的叶绿素浓度资料研究浙江沿岸上升流的短周期变化,并结合同期的QuikSCAT风场资料,分析西南季风对上升流的影响.遥感观测结果表明,夏季研究海域内分布有两处上升流,浙江沿岸上升流位于29°-31°N,121.5°-123°E,核心区位于30°N附近,长江口上升流位于31°-32°N,122.5°-124°E,核心区大约在31.5°N附近,两者经常连在一起并呈长舌状分布在浙江沿岸,其沿西南一东北走向两侧具有明显的海洋锋现象.研究海域内低温海水约24-27℃,平均温度约25℃,低温区面积约10000一16000km2,平均面积约13690km2.2004年上升流季节变化明显,6月份出现在海面,7-8月份达到强盛期,9月份上升流开始衰退直至消失.叶绿素浓度结果表明,浙江近海分布有高叶绿素浓度,SST低温区与高Chl-a区在时间、位置和形状上保持较好的一致性.同期海面风场表明,上升流强盛期,海面多盛行偏南风,相反,则盛行偏北风.沿岸风的变化是研究海域内上升流发生短期变化的一个重要因子.

Sea surface temperature derived from NOAA/AVHRR and chlorophyll-a derived from MODIS and SeaW iFS\naswell asQuikSCATwind vectors data during summer(fromMay toOctober) in 2004 have been used to investigate the short-term variability ofupwelling events in Zhejiang coastalareas·Short-term observations ofsatellite mi agesduring summer of2004 have revealed two upwelling zones in the study area·The upwelling nearZhejiang coastal areas is located at 29°—31°N, 121·5°—123°E, with the upwelling core near30°N, and the upwelling nearYangtzeRiver estuary is located at31°—32°N,122·5°—124°E, with the upwelling core near 31·5°N·These areas are noted for their high fisheries production·Upwelling looks like a long tongue in shape in Zhejiang coastal zones, the sea surface thermal frontexists obviously in its southeastern edge·The temperature difference between the upwelling and non-upwelling areas is about3—4℃for July; the low temperature in the study area is about24—27℃, with amean value of25℃; the size ofupwelling is about10000~16000 km2, with amean value of 13690 km2·The seasonal variability is obvious in 2004, upwelling started to appear in June and achieved powerfully in July andAugust, itassumed theweaken ed tendencyuntilvanished in September·Chlorophyll-a data ofMODIS-derived and SeaW iFS-derived showed thathigh Chl-a areas coincided with low SST areas in terms of location, tmi e and shape·The relationship between upwelling intensity and sea surfacewind field is analyzed by usingAVHRR SST andQuikSCATwind field, the resultshows thatthe variationsofsea surfacewind speed as well aswind direction coincidewith the variationsofupwelling, which indicates the southwestwind alongshore off Zhejiang coast is an mi portant factor for the variations ofupwelling·