摘要
利用中分辨率成像光谱仪(moderate resolution imaging spectroradiometer, MODIS)一级产品并结合航次数据,反演2003-2015 年间珠江河口表层悬浮泥沙浓度(suspended sediment concentration, SSC),分析其分位数长期变化趋势并探讨其影响因素。结果表明,珠江河口 SSC 呈总体下降趋势,平均下降速率约为 1.03mg L^-1 yr^-1。口门外以及河口东北部区域平均 SSC 下降更快,最高可达约 4.0mg L^-1 yr^-1。总体上,珠江河口 SSC 高值下降速率大于低值,且存在空间差异性。低值下降趋势显著地区主要分布在淇澳岛北部的口门外区域,其 SSC 大小值之间的差异逐年增加;而高值下降速率快的地区主要分布在虎门口、龙穴岛东南岸以及东航道附近水域, SSC 每年大小值差异呈减小趋势。珠江河口 SSC分位数趋势受径流输沙量、河口地形变化以及风的影响。由水库修建所致的上游输沙量减少导致淇澳岛北部口门外区域 SSC 的低值部分显著下降。虎门口、龙穴岛东南岸以及东航道附近水域的加深使得这些区域 SSC 高值部分下降显著,而西滩区域的变浅使得冬季潮汐混合减弱,导致 SSC 高值部分下降趋势显著。此外,由风速下降引起的表层风混合减弱也是导致西滩南部 SSC 高值下降趋势显著的原因之一。
Suspended sediment concentration (SSC) in the Pearl River Estuary (PRE) during 2003-2015 was studied based on Moderate Resolution Imaging Spectroradiometer (MODIS) Level-1B product and in-situ measurements. The data were further used to analyze quantile trends and corresponding influence factors. The results showed that the SSC in the PRE displayed a decreasing trend, with an averaged SSC reduction rate of about1.03 mg·L^–1·yr^–1. The SSC in the regions near the river outlets and northeast part of the estuary suffered from much stronger decreases, which could be up to 4.0 mg·L^–1·yr^–1 during 2003-2015. Decreasing rate in high SSC were generally larger than those in low SSC, with a marked spatial difference. Low percentile of the SSC suffered from a stronger decline in the regions north of Qiao Island, with an increase in the variance of the distribution, while remarkable trends of high percentile of SSC occurred in the Humen outlet, northeastern coast of Longxue Island and regions near the East Channel, with corresponding decreases in the variance of the distribution. The quantile trends in the PRE were influenced by many factors. The seasonal variation of dam-induced reduction of the sediment load into the PRE contributed to most of the low-percentile SSC decreases north of Qiao Island. The subaqueous topographic change in the PRE induced by human activities dominated the high-percentile SSC trends in the Humen outlet, northeastern coast of Longxue Island, southern West Shoal, and regions near the East Channel. The decrease of the wind speed over the PRE also affected the high-percentile SSC trend in the southern West Shoal by weakening wind mixing in the boundary layer.
作者
詹伟康
吴颉
韦惺
唐世林
詹海刚
ZHAN Weikang;WU Jie;WEI Xing;TANG Shilin;ZHAN Haigang(State Key Laboratory of Tropical Oceanography (South China Sea Institute of Oceanology,Chinese Academy of Sciences),Guangzhou 510301,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《热带海洋学报》
CAS
CSCD
北大核心
2019年第3期32-42,共11页
Journal of Tropical Oceanography
基金
广州市科技项目(201607020042)
热带海洋环境国家重点实验室自主研究项目(LTOZZ1503)~~
关键词
悬沙浓度
MODIS
珠江河口
分位数趋势
Suspended sediment concentration
MODIS
Pearl River Estuary
quantile trend
