温室气体浓度增加情景下西北太平洋热带气旋变化的模拟分析

A Simulation Study of Tropical Cyclone Changes under the Concentration Increase Scene of Greenhouse Gases

利用德国Max-Planck气象研究所参与政府间气候变化委员会(The Intergovernmental Panelon Cli-mate Change,IPCC)第四次评估报告的气候系统模式(ECHAM5/MPI-OM)的数值模拟结果,分析研究了全球增暖背景下西北太平洋热带气旋的变化。结果表明,ECHAM5模式较好的模拟出了热带气旋的基本结构和频数的分布特征。当大气中CO2浓度增加时,热带气旋中心的最低气压升高,850hPa正涡度降低,风速减小,风场出现反气旋性环流异常,暖心强度减弱,气旋的低层径向流入和高层径向流出减少,气旋总体强度减弱。CO2浓度的增加会总体上减少西北太平洋热带气旋的生成频数,从模拟结果看年均减少10个左右。就CO2浓度增加对热带气旋频数季节变化的影响而言,CO2浓度增加所引起气旋频数减少较平均的分配到多个月份里,表明CO2浓度增加引起的大气环流异常在全年都会对西北太平洋热带气旋的发生频数产生影响。分析加拿大参加IPCC第四次评估报告的CGCM3.1(T47)模拟资料,其结果与ECHAM5资料得到的结果大致相似。

The numerical simulation data of a new climate model （ECHAM5/MPI-OM） developed at Max-Planck Institute for Meteorology are used to analyze the variation of tropical cyclones in the western North Pacific under the global warming scenarios. The result shows that ECHAM5 model can simulate the distribution characteristics of basic structure and frequency of tropical cyclones well. The increase of CO2 in atmosphere coincides with the incresase in the lowest center pressure,decrease in vorticity at 850 hPa,less lower radial influx and less upper radial outflux,negative wind velocity anomalies and anti-cyclonic circulation anomalies at low levels,and lower warm core temperature in the tropical cyclones in the western North Pacific. In a word,the intensity of tropical cyclones in the western North Pacific became weak. The increase of CO2 in the atmosphere causes the decrease in the frequency of tropical cyclones in the western North Pacific. There is an annual reduction of about ten tropical cyclones in the model. This decrease distributes in several months,which indicates that the general atmospheric circulation anomalies caused by the increase of CO2 in atmosphere would influence the frequency of tropical cyclones in the whole year. Analyzing the simulation data in the CGCM3.1,some similar results are shown.