利用多源数据研究东南极百年尺度的极端温度事件

With global climate warming, weather extremes and climate extremes happen more frequently and intensely. Therefore, it is a focus for research on global climate change to further reduce the uncertainties in projections of centennial-scale climate and climate extremes in Antarctica. The project will aim to confirm the better method suitable to East Antarctica from many interpolation methods, and then to compare and assess the accuracy of daily temperature extremes from different reanalyses against in-situ observations. The daily temperature maximum and minimum of in-situ observations is from the automatic weather stations (AWS) at Zhongshan station, LGB69, PANDA-N, EAGLE, Dome A and PANDA-S, which are situated between the coast and the ice sheet summit in East Antarctica, along approximately 77E longitude. The reanalyses considered are NCEP/NCAR (referred to as NCEP-1), NCEP/DOE AMIP-II (NCEP-2), the second version of the Twentieth Century Reanalysis (20CRv2), NCEP Climate Forecast System Reanalysis (CFSR), NASA MERRA, the ECMWF reanalysis (including ERA-40 and ERA Interim) and the real-time operation of the JMA Climate Data Assimilation System (JCDAS). The interpolation methods suggested are Inverse Distance to a Power, Kriging, Minimum Curvature, Polynomial Regression, Bilinear Interpolation, Nearest Neighbor, Spline function, etc. Based on the AWS and reanalysis data with long time series, multi datasets are combined to study on the centennial-scale climate change, and on changes and mechanism of climate extremes in East Antarctica. The multi datasets referred here are from AWS observations in the neighboring regions, reanalyses, surface snow, ice/snow core, sea ice, CRU and remote sensing. With the IPCC AR5 CMIP5 models, the project estimates the climate change and climate extremes in East Antarctica. Building on the existing achievements in Antarctica, the project will establish a complex database for research on centennial-scale climate change in East Antarctica, and fill an important gap in research on centennial-scale climate change and climate extremes in East Antarctica. In addition, the project will reduce the uncertainties in projections of climate change and climate extremes in Antarctica.

全球气候系统变暖，极端天气与气候事件发生的频率和强度增加。然而，南极地区极端气候事件的研究尚不多见。本项目基于东南极冰盖边缘至内陆的中山站、LGB69、EAGLE和Dome A气象站的实测的日最高/最低气温，对比研究多种再分析资料（NCEP-I、NCEP-2、20CRv2、CFSR、MERRA、ECMWF和JCDAS）在本地区适用性的最佳插值方法，探讨再分析资料刻画极端温度事件的准确性；通过时间序列较长的再分析资料20CRv2（1871年至今），与东南极地区及其附近的实测气象资料、雪/冰芯、表层雪、海冰、CRU、遥感资料相结合，研究东南极地区近百年以来的气候变化，探讨东南极地区极端温度事件的变化规律及其成因机制；本研究可填补东南极地区极端气候事件研究的空白，为将来减小南极地区近百年以来的气候变化模拟研究的不确定性，提供科学依据。

极端天气与气候事件发生的频率和强度日趋增加，已经成为国际社会关注的焦点。然而，针对南极地区的此类研究尚不多见。基于东南极冰盖边缘至内陆的实测日最高/最低气温，本项目系列评估对比了多种再分析资料在本地区的适用性，认为ERA Interim在东南极地区的适用性最强，能够更好地反映研究区极端气温事件；分析了研究区最高/最低气温特征，认为其极端天气事件的发生，主要源于地面冷高压和绕极低压的中心位置的移动和强度的变化；对比研究了近三十年中山站和长城站的极端气温，认为两站最低气温增温强，日温差减小，极端暖日减少，“无芯冬季”明显，年代际气候变化具有“跷跷板”特征；中山站融化日数增加，而长城站不明显。.Polar WRF模式模拟Dome A区域结果显示，极端低温事件主要中纬度地区的高压增强，向南入侵南极大陆，使得本区域受高压控制；极端高温事件发生时，500hPa位势高度场具有不同的表现形式，正常状态下随纬度增高地面气压下降的趋势被外部扰动打破，极锋区域强度减弱，南极中心冷涡减弱，暖湿气流在高空形成保温盖。20个CMIP5模式能较好地模拟考察断面的最高/最低气温的变化趋势，在Dome A模拟最好，在中山站模拟效果最差；在中山站呈现显著的冷偏差，在其余三站最高气温模拟呈现冷偏差，最低气温模拟呈现暖偏差，减小了气温的日较差范围；选择对研究区域最高/最低气温的模拟能力优于其他模式的5个模式，进行加权平均多模式集合，提高了模拟能力水平，有效克服了单一模式的局限性。通过Polar WRF和CMIP5模式的初步研究，为预估、预测未来南极的天气与气候变化，奠定了科学基础。.自行改进和研发的蒸汽钻机，经过数次改进和试验，连续跟随野外考察队，在近10条冰川顺利布设百余根花杆。发表论文11篇（SCI 6篇，核心5篇），其中第一、二标注论文6篇（SCI 3篇，核心3篇），已获授权发明专利3项。培养硕士研究生5名（毕业3名，在读2名），协助培养博士研究生2名（毕业1名，在读1名），1人被聘为中国专利审查技术专家。