北京气候中心气候模式1.1版预估中亚地区未来50年地面气温时空变化特征

Projection of the spatial and temporal variation characteristics of surface air temperature over central Asia in the next 50 years in the Beijing Climate Center Climate System Model V1.1

中文关键词:  中亚  地面气温  BCC-CSM1.1模式  典型排放路径  经验正交函数

英文关键词:Central Asia  Surface air temperatures  BCC-CSM1.1  RCPs  EOF

中文摘要:

      利用IPCC AR5中BCC-CSM1.1(Beijing Climate Center Climate System Model version 1.1)的历史试验和4类典型 排放路径情景下未来预估试验结果, 在使用CRU(Climatic Research Unit)资料验证BCC-CSM1.1性能的基础上, 采用趋势分 析、滑动平均以及经验正交函数(EOF)等方法, 研究2011-2060年中亚地区年平均气温的时空演变特征。与CRU 资料的对 比分析发现BCC-CSM1.1能较好地模拟过去109a(1901-2009年)中亚地区气温的显着上升趋势及气候态的空间分布特征。 预估试验结果表明, 中亚地区在未来50a整体呈现变暖趋势, 并且, 随着温室气体排放浓度的升高, 气温的升高趋势愈加明 显, 同时增温显着区域也明显增大。经验正交函数分解主要模态还是延续过去的分布特征:经验正交函数分解第1模态及其 所对应的时间系数显示中亚地区年平均地面气温在未来50a(2011-2060年)呈现出全场一致的升高趋势, 升高强度随着温 室气体排放浓度的增加而增强, 进一步的分析表明, 不同典型排放路径下预估的未来50a中亚地区年平均地面气温的经验正 交函数分解第1模态在中亚上空850hPa等压面上均对应有一个反气旋(气旋)性异常环流, 在这个异常环流控制下, 中亚地 区年平均地面气温变化表现为全场一致的特征。经验正交函数分解第2模态呈现出中亚地区地面气温变化南北反位相的基 本特征, 相应的时间系数主要表现为小幅度波动, 变化趋势特征不明显。

英文摘要:

      Based on the CRU(Climatic Research Unit) dataset and the outputs of the historical and 4 representative concentration pathways (RCPs) future projection experiments from the BCC-CSM1.1 (Beijing Climate Center Climate System Model version 1.1) climate model for the IPCC AR5(Intergovernmental Panel on Climate Change: the Fifth Assessment Report), the temporal and spatial distributions of the annual mean surface air temperature over central Asia under the four RCPs during 2011 to 2060 have been studied by using the trend analysis, moving average, and EOF methods. Comparison of the BCC-CSM 1.1 historical experiment outputs with the CRU observed data showed that the BCC-CSM 1.1 model well simulated the significant upward trend, temporal evolution and spatial distribution of the annual mean surface air temperature over central Asia during the past 109 years(1901-2009). The annual mean surface air temperatures regionally averaged over central Asia in the future projection experiments under the 4 RCPs all displayed warming trends in the next 50 years (2011-2060). It also can be noted that the temperature warming rates and the regions with significant increasing temperature rates increase with the increased RCPs. The EOF analysis results showed that the features of the main EOF modes of the annual mean surface air temperature over central Asia from the 4 RCPs experiments arc very similar to their historical patterns. The EOF1 mode and its time coefficients show that the annual mean surface air temperature over central Asia will spatially consistently increase in the next 50 years. The warming rates of the annual mean surface air temperature over central Asia increase with the increased green gas emission, and further analysis showed that a cyclonic (anticyclonic) anomalous circulation at 850 hPa level associated with the EOF1 modes of the projected annual mean near surface air temperature under the 4 RCPs in the next 50 years resulted in the spatially consistent increase in the annual mean near surface air temperature over central Asia. However, the EOF2 modes of the annual mean surface air temperatures from the 4 RCPs future projections all show significant features of inverse phase for the north to the south over central Asia. Corresponding time coefficients have no significant linear trends and show fluctuations within a narrow range.