Sensitivity of the half-life time of water exchange in coastal waters  

作　　者：Zhenhua CHEN Fangli QIAO Gang WANG Changshui XIA 

机构地区：[1]The First Institute of Oceanography, State Oceanic Administration [2]Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology [3]Key Laboratory of Marine Science and Numerical Modeling (MASNUM), State Oceanic Administration

出　　处：《Science China Earth Sciences》2019年第4期643-656,共14页中国科学（地球科学英文版）

基　　金：supported by the NSFC-Shandong Joint Fund for Marine Science Research Centers(Grant No.U1406404);the Fundamental Research Funds for National Public Research Institutes of China(Grant No.2014T01);the National Program on Global Change and Air-Sea Interaction(Grant No. GASI-03-IPOVAI-05);supported by the AoShan Talents Program;the Qingdao National Laboratory for Marine Science and Technology(Grant No. 2015ASTP)

摘　　要：A three-dimensional model was established to investigate water exchange in coastal waters, and applied to Qinzhou Bay(QZB) in the South China Sea. Given the strong tidal current in QZB, a half-life time was calculated for water exchange by filtering the tidal signal from the concentrations of a conservative substance. In a control run driven by the tide, without external inputs and an open boundary concentration of zero, it was estimated that the average half-life time in QZB was 54.8 d. Numerical experiments showed that wind accounted for an 11.9% reduction in the half-life time to 48.3 d. When rivers were included in the model, the half-life time decreased by 74.6% to 13.9 d. Sensitivity experiments showed that the half-life time for water exchange was greatly affected by the concentration of the conservative substance which was used at the open boundary. In response to 10,20, 30, and 40% increases in the boundary concentration, the half-life time increased to 91.5, 168.3, 186.2, and 229.1 d,respectively. Results also suggested that for coastal bays with large intertidal areas such as QZB, consideration of the wet and dry processes produced more accurate simulations of the hydrodynamics and the half-life times. Simulations, which did not incorporate wet and dry processes, were more than likely to have overestimated or underestimated the half-life times for water exchange.A three-dimensional model was established to investigate water exchange in coastal waters, and applied to Qinzhou Bay(QZB) in the South China Sea. Given the strong tidal current in QZB, a half-life time was calculated for water exchange by filtering the tidal signal from the concentrations of a conservative substance. In a control run driven by the tide, without external inputs and an open boundary concentration of zero, it was estimated that the average half-life time in QZB was 54.8 d. Numerical experiments showed that wind accounted for an 11.9% reduction in the half-life time to 48.3 d. When rivers were included in the model, the half-life time decreased by 74.6% to 13.9 d. Sensitivity experiments showed that the half-life time for water exchange was greatly affected by the concentration of the conservative substance which was used at the open boundary. In response to 10,20, 30, and 40% increases in the boundary concentration, the half-life time increased to 91.5, 168.3, 186.2, and 229.1 d,respectively. Results also suggested that for coastal bays with large intertidal areas such as QZB, consideration of the wet and dry processes produced more accurate simulations of the hydrodynamics and the half-life times. Simulations, which did not incorporate wet and dry processes, were more than likely to have overestimated or underestimated the half-life times for water exchange.

关 键 词：Sensitivity CONVECTION-DIFFUSION model Water exchange HALF-LIFE time Qinzhou BAY SOUTH China SEA 

分 类 号：P[天文地球]