RegCM4对华北区域21世纪气候变化预估研究

利用国家气候中心完成的RegCM4区域气候模式在RCP4.5和RCP8.5两种排放路径下的气候变化动力降尺度试验结果,在检验模式对基准期(1986—2005年)气温和降水模拟能力基础上,进行华北区域21世纪气候变化预估分析。结果表明:RegCM4对华北区域基准期气温和降水的模拟能力较好。未来21世纪,两种情景下华北区域气温、降水、持续干期(consecutive dry days, CDD)和强降水量(R95p)变化逐渐增大,但变化幅度在高排放的RCP8.5情景下更为显著,其中近期(2021—2035年)、中期(2046—2065年)、远期(2080—2098年)RCP8.5情景下年平均气温分别升高1.77、3.44、5.82℃,年平均降水分别增加8.1%、14%、19.3%,CDD分别减少3、3、12 d, R95p分别增加30.8%、41.9%、69.8%。空间上,未来21世纪华北区域内年、冬季、夏季平均气温将一致升高,夏季升温幅度最大;年、冬季、夏季平均降水整体以增加为主,冬季降水增加幅度最大;CDD以减少为主,但近期和中期在山西和京津冀有所增加,而R95p以增加为主,表明21世纪华北区域干旱事件逐渐减少、极端降水事件不断增加。

Estimation of climate change in the 21st century in North China by RegCM4

Based on dynamic downscaling simulation data of temperature and precipitation by the regional climate model version 4(RegCM4) from National Climate Center under the representative concentration pathways 4.5(RCP4.5) and RCP8.5 scenarios, the simulation ability of RegCM4 was tested in baseline period(1986-2005). And on this basis, the climate change was analyzed in North China in future of the 21 st century. The results show that RegCM4 had a better performance in simulating air temperature and precipitation in North China in baseline period. The change of surface air temperature, precipitation, consecutive dry days(CDD) and strong precipitation(R95 p) under RCP4.5 and RCP8.5 scenarios will increase gradually in North China in future of the 21 st century, but their changes under RCP4.5 scenario will be obviously less than those under RCP8.5 scenario. Under the higher emission scenario of RCP8.5, the annual mean air temperature will rise 1.77, 3.44 and 5.82 ℃ in near term(2021-2035), medium term(2046-2065) and long term(2080-2098) of the 21 st century, the annual mean precipitation will increase 8.1%, 14% and 19.3%, CDD will reduce 3, 3 and 12 d, and R95 p will increase 30.8%, 41.9% and 69.8%, respectively. In space, the mean air temperature in the whole year, winter and summer in North China will rise consistently in future of the 21 st century, and the warming in summer will be the most, while the mean precipitation in the whole year, winter and summer will increase in most regions, and the increase of precipitation in winter will be the most. Meanwhile, CDD will decrease except in Shanxi and Beijing-Tianjin-Hebei areas in near term and medium term, while R95 p will increase, which indicated that the drought events will reduce and the extreme precipitation will increase in the 21 st century.