近60年来渤海海域波候变化及其与东亚环流的联系

Wave Climate Changes in Bohai Sea Related to the East Asian Circulation Oscillations over the Last Sixty Years

研究海洋的波候变化是了解海洋动力过程对气候变迁响应的关键。渤海所处特殊的地理位置,使其波候在长期风场变化影响下存在阶段性变化特征。文章采用1950～2011年NCEP再分析资料中的渤海海域10 m风场资料,利用SWAN模式模拟逐月渤海波浪的有效波高、波向、波周期,分析该海区波候的变化特征。分析结果显示：1950～2011年期间渤海海域的有效波高呈现下降的趋势;波向角度均呈现上升的趋势,波周期相对平稳,略有上升;有效波高平均下降0.3 cm/a,波向角度平均增加0.12°/a。有效波高在1968年前后显现突变点,波向角度约在1960年突变,波周期在1965年左右出现突变点。渤海波候变化与海气振荡密切相关,是大尺度的大气环流变异导致的结果,长期气候变化背景下,东亚环流天气系统的长期变化（包括东亚季风强度、夏季风北界的移动,西太平洋副热带高压面积与强度的变化、脊点位置西伸与北进,以及西风指数的强弱变化等）,是影响和控制渤海海域波气长期变化的主要原因。

Researching on wave climate change is the key to understanding the dynamic processes of the ocean when climate has changed. Bohai Sea is located on the northern edge of the East Asian Circulation, and the characteristics of wave climate stage change in this area has been influenced in long-term wind change. Multi-scale variability characteristics of wave climate from 1950 to 2011 are studied based on NCEP reanalysis data. Wave climate in the Bohai Sea during 1950 to 2011 have been simulated by SWAN model. Results showed that： the significant wave height decreased in past 62 years; wave direction increased and wave period changed smoothly. The average decrease in significant wave height was 0.3 cm/a, and the increase in the wave angle was 0.12°/a. The abrupt of significant wave height occurred around 1968; the abrupt change of wave direction occurred around 1960; the abrupt change of wave period occurred in 1965. Wave climate in Bohai Sea is mainly determined by oscillation of the large-scale atmospheric circulation. Because of its unique geographic location, wave climate is affected and controlled by all three weather systems （e.g., the East Asian monsoon, the West Pacific subtropical high, and the Westerly wind belt） mentioned above.