CMIP5模式对登陆中国热带气旋活动的模拟和预估

Climate change projection of the landfalling tropical cyclone in China:results of CMIP5 models

基于中国气象局热带气旋最佳路径数据集,结合7个全球耦合模式在4个气候情景(Historical、RCP2.6、RCP4.5、RCP8.5)下的模拟场,对比分析了模式模拟1986—2005年登陆我国热带气旋(LTC)活动的气候特征,并评估了未来(2026—2045年)不同气候情景下LTC活动的频数和强度变化特征。结果表明:在Historical情景下虽然各模式模拟的1986—2005年LTC均少于观测值,但仍然较好的再现LTC的季节分布、地理位置分布和强度分布特征。未来气候情景下不同强度LTC的频数预估则显示,相对于Historical情景,RCP2.6和RCP8.5情景下较弱的LTC有减少的趋势,而较强的LTC则表现为略微的增加。另外,对比不同模式的结果可以发现,模式中若中国大陆近海区域平均垂直风切变和海平面气压较大,则其对应的LTC活动较少;若模式中海表温度较高,则LTC的平均登陆强度较大。

Based on Landfalling Tropical Cyclone （LTC） Best-Track （BST） Data from China Meteorological Administration （CMA） and 7 Global Climate Models （GCMs） outputs under historical scenario during 1986- 2005 and the Representative Concentration Pathways, this paper firstly investigated the simulated LTC from the GCMs in contrast with the BST. Then the change of frequency and intensity of future LTCs from the GCMs under the RCPs （RCP2.6, RCP4.5, RCP8.5） over 2026-2045 are also detected and projected. The result show that, the LTCs from GCMs well reproduce the observed LTC seasonal, geographical position and intensity probability distribution although the frequency of LTCs detected from the GCMs are all less than observed. With respect to the reference period 1986-2005 of historical simulation, the annual mean occurrence frequency of weak LTCs decrease while strong ones increase under RCP2.6 and RCP8.5 scenario. It turns out that the annual mean occurrence frequency of LTCs has a significant negative relationship with the regional average vertical wind shear and sea level pressure between GCMs, while the average landing intensity show a significant positive correlation with sea surface temperature. However, when turn to the ensemble mean of GCMs, the change of LTCs frequency and intensity among each scenarios do not show any consistency with the corresponding environment factors.