中尺度涡控制悬浮体的分布——以帕里西维拉海盆区为例

为研究帕里西维拉海盆区上层水体中悬浮体分布特征,对2003年冬季在该海区现场测得的上层水体悬浮体质量浓度数据进行详细分析。结果表明,调查期间研究区悬浮体质量浓度在水平上表现出西高东低的特征,垂向上的差异较小。现场大面站调查和同期卫星高度计数据显示,调查期间在研究区海域同时存在冷涡和暖涡活动,其中冷涡活动区位于研究区西部,暖涡活动区位于东部。分层分析表明,调查区中尺度涡活动对悬浮体分布有明显的控制效应:在冷涡活动区内,深层的富营养盐水体上涌,使冷涡内部的浮游生物量增多,导致冷涡活动区内的悬浮体质量浓度明显高于周围;在暖涡活动区内,因上层的寡营养盐水体下沉,使暖涡区的浮游生物量减少,导致悬浮体质量浓度明显低于周围。受洋流和中尺度涡活动的影响,调查海区西北部岛礁的物质供应也是导致研究区悬浮体分布呈现西高东低格局的重要因素。

MESOSCALE EDDY CONTROLS THE DISTRIBUTION OF SUSPENDED PARTICULATE MATTER AS SHOWN IN THE PARECE VELA BASIN

Based on the data of suspended particulate matter (SPM) obtained by CTD in winter 2003, we discussed the distribution characteristics of SPM in the upper water of the Parece Vela Basin in the western Pacific. Results show that the value of SPM was much higher in the western than in the eastern parts of the basin, and changed slightly in vertical direction. Analysis on the CTD data and the altimeter observation in NW Pacific showed that cold and warm eddies were active simultaneously. Cold eddies were located in the western parts of the study area and the warm ones in the eastern. These mesoscale eddies controlled clearly the distribution of SPM. In cold eddy areas, cold nutrient was upwelled, by which biomass in subsurface layers was enriched, and the concentration of SPM increased, and vice versa in warm eddy case. Under the influence of the ocean current and mesoscale eddies, substance supply from reefs to the northwest of the study region was also an important contributor for causing higher SPM concentration in the eastern part than in the western part.