Numerical simulation of a synoptic event in the Southern California Bight
Numerical simulation of a synoptic event in the Southern California Bight
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DOI：
10.1029/2010jc006578
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发表时间：
2011-05-26
影响因子：
3.6
通讯作者：
Hughes, Mimi
中科院分区：
文献类型：
--
作者：
Dong, Changming;McWilliams, James C.;Hughes, Mimi
2002 年 3 月中旬，南加州湾发生了一场天气上升流事件；其特点是海岸 10 至 20 公里范围内急剧降温至少 4 摄氏度。到月底，事件前的气温已缓慢恢复。区域海洋模型系统（ROMS）用于通过对表面风和浮力通量强迫进行大气降尺度再分析来模拟该事件。温度、盐度、速度和海平面的横向边界条件取自全球海洋产品。来自全球正压模型的正压潮汐场沿着开放边界施加。与观测数据相比，模拟很好地再现了上升流过程。检查模拟对风分辨率、热通量和潮汐力的敏感性。海洋对不同风分辨率的响应收敛于 6 公里分辨率水平，这是大气降尺度中使用的地形高程数据集中存在的最精细尺度。太阳辐射的昼夜循环分析与瞬时 ROMS 海面温度的经验耦合相结合，产生了对缩小热通量的类似海洋响应。由于风和表面流的准共振排列（可能是偶然的）导致风能输入增加，潮汐效应在上升流演化中非常重要。
In the middle of March 2002 a synoptic upwelling event occurred in the Southern California Bight; it was marked by a precipitous cooling of at least 4 degrees C within 10-20 km of the coast. By the end of the month the preevent temperatures had slowly recovered. The Regional Oceanic Model System (ROMS) is used to simulate the event with an atmospheric downscaling reanalysis for surface wind and buoyancy flux forcing. Lateral boundary conditions of temperature, salinity, velocity, and sea level are taken from a global oceanic product. Barotropic tidal fields from a global barotropic model are imposed along the open boundaries. The simulation reproduces well the upwelling process compared with observed data. The sensitivity of the simulation is examined to wind resolution, heat flux, and tidal forcing. The oceanic response to the different wind resolutions converges at the level of the 6 km resolution, which is the finest scale present in the terrain elevation data set used in the atmospheric downscaling. The combination of an analytical diurnal cycle in the solar radiation and the empirical coupling with the instantaneous ROMS sea surface temperature produces a similar oceanic response to the downscaled heat flux. Tidal effects are significant in the upwelling evolution due to the increase in wind energy input through a quasi-resonant alignment of the wind and surface current, probably by chance.