多模式集成的概率天气预报和气候预测研究进展   总被引：2，自引：2，他引：2       下载免费PDF全文

智协飞  彭婷  李刚  王佳  王晶 《大气科学学报》2014,37(2):248-256

基于大气的混沌特性,单一的确定性预报逐步向多值的不确定性概率预报转化已成为一种趋势。本文系统地评述了概率天气预报产生的背景,介绍了概率预报的相关概念及国内外的研究状况,着重讨论了多模式集成的概率预报的两种集成方法,即贝叶斯模式平均(Bayesian model averaging,BMA)和多元高斯集合核拟合法(Gaussian ensemble kernel dressing,GEKD),并给出了两个例子的概率预报试验结果。利用BMA方法制作的概率预报的方差较小,减小了预报的不确定性,因此预报结果更接近大气的真实值。作为另一种多模式集成方法,多元高斯集合核拟合法回报的地面气温距平均值及趋势的概率预测结果与实测结果基本一致。利用此方法建立了地面气温年代际变化的概率多模式集合预测模型,并从中提取年代际气候变化特征,对东亚季风区年代际预测具有重要应用价值。  相似文献   

全球变暖背景下我国春季气温的时空变化特征   总被引：8，自引：6，他引：2  

董李丽  李清泉  丁一汇 《气象》2015,41(10):1177-1189

利用我国台站观测逐日气温资料和美国NCEP/NCAR再分析大气环流资料,通过分析比较我国1951—1980和1981—2010年两个时段春季气温的季节、月、候时间尺度的气候平均特征,研究20世纪80年代以后的春季气温和季节进程的变化特征,并初步探讨了春季气温变化的可能原因。结果表明：20世纪80年代以后,除了西南等地,全国大部分地区春季增温,由东北到西南呈现气温“升高—降低”的形势。在春季3—5月,除西南局部地区气温下降外,全国其余大部分地区气温升高0~1℃。3—5月季节进程在江南和西南东部地区加快,内蒙古和华南南部地区则经历了由快到慢的变化,东北地区、西南地区南部、西北地区北部春季进程速度减慢。总体来说,在全球变暖背景下,我国东部地区春季开始早、结束早,西部地区春季开始和结束时间变化不明显。与1951—1980年相比,20世纪80年代以后,春季乌拉尔山地区高压减弱,东亚大槽减弱,亚洲中高纬地区纬向环流加强,西太平洋副热带高压加强,东亚副热带西风急流明显增强,因此不利于来自北半球极地和高纬地区的冷空气影响我国,我国大部（特别是东北）地区春季气温偏高。但是,中东急流偏强,东亚副热带急流偏南,有利于欧洲中东部冷空气影响我国西南地区,导致西南地区气温偏低;同时,南支槽偏弱,不利于印度洋和孟加拉湾的暖湿气流向北影响我国西南地区,也使得西南地区气温易于偏低。  相似文献   

Interdecadal Variability in Large and Small Warm Pools in Western Pacific and Their Association with Rainfall Anomalies          下载免费PDF全文

ZHOU Lian-Tong 《大气和海洋科学快报》2014,(1)

This study investigated interdecadal variability of June–October(JJASO) the large and small warm pools in western Pacific and their association with rainfall anomalies using station and reanalysis data from 1958 to 2008.The results indicated that the large and small warm pools in western Pacific showed an interdecadal shift around 1986.The large warm pool years over western Pacific were found after 1986,whereas the small warm pool years were often seen throughout the periods before 1986.The analysis results also showed that there were obvious interdecadal variability in JJASO rainfall in Southeast China and warm pool in western Pacific.During 1958–1985(small warm pool years),the decrease in rainfall was associated with tropospheric moisture divergence and sinking motion over Southeast China and warm pool in western Pacific.However,during 1986–2008(large warm pool years),the increase in rainfall was associated with tropospheric moisture convergence and ascending motion.Further analysis showed that large warm pool contributed to the increase in surface latent heat fluxes over warm pool in the western Pacific.Thus,there was an increase in the amount of water vapor over Southeast China and warm pool in western Pacific,which contributed to increased rainfall in these regions.  相似文献   

Interdecadal and Interannnual Variabilities of the Antarctic Oscillation Simulated by CAM3          下载免费PDF全文

XUE Feng  SUN Dan  ZHOU Tian-Jun 《大气和海洋科学快报》2014,7(6):515-520

Based on four sets of numerical simulations prescribed with atmospheric radiative forcing and sea surface temperature（SST） forcing in the Community Atmospheric Model version 3（CAM3）, the interannual and interdecadal variabilities of the Antarctic oscillation（AAO） during austral summer were studied. It was found that the interannual variability is mainly driven by SST forcing. On the other hand, atmospheric radiative forcing plays a major role in the interdecadal variability. A cooling trend was found in the high latitudes of the Southern Hemisphere（SH） when atmospheric radiative forcing was specified in the model. This cooling trend tended to enhance the temperature gradient between the mid and high latitudes in the SH, inducing a transition of the AAO from a negative to a positive phase on the interdecadal timescale. The cooling trend was also partly weakened by the SST forcing, leading to a better simulation compared with the purely atmospheric radiative forcing run. Therefore, SST forcing cannot be ignored, although it is not as important as atmospheric radiative forcing.  相似文献   

中国气温和降水序列年代际分量的显著性检验     

谢瑶瑶  李丽平  王盘兴  罗小莉 《南京气象学院学报》2011,34(4):467-475

对1951—2008年中国160站年和四季的气温、降水序列是否服从正态分布进行显著性检验,以此为基础进一步对气温和降水序列中的年代际异常分量显著性作了严格的统计学分析,结果表明：1）大多数测站气温序列服从正态分布,大多数测站降水序列不服从正态分布;气温、降水序列是否服从正态分布与地域有一定联系。2）气温、降水序列中年代际变化分量的显著性存在明显差异,多数测站气温序列年代际分量显著,只有少数测站降水序列的年代际分量显著。3）因为1951—2008年中国160站年、季气温和降水序列不全服从正态分布,特别是降水序列的非正态性严重,建议对它们的统计显著性检验采用Monte Carlo方法。  相似文献   

大西洋热盐环流年代际变化机制研究Ⅲ.北大西洋海气要素对热盐环流年代际振荡的影响     

牟林  陈学恩  宋军  李欢  李琰  姜晓轶  李海  陈幸荣 《海洋学报(英文版)》2011,30(4):19-28

基于该系列文章前文研究中构建的海气耦合气候模式和所揭示的北大西洋热盐环流年代际振荡机制,针对海气要素对该振荡机制的影响问题进行了重点的探讨。为细致准确的研究北大西洋海洋要素同北大西洋热盐环流年代际振荡的关系,有针对性的定义了副极地海区表层密度指数和北大西洋暖流强度指数并对模式结果进行了全面分析。分析结果表明副极地海区表层密度变化领先大西洋径向翻转环流(MOC)变化7 a,北大西洋暖流的变化领先 MOC变化4 a,格陵兰－苏格兰海脊溢流水强度(包括丹麦海峡溢流水和法鲁海峡溢流水,是北大西洋深层水的重要来源)的变化领先 MOC的变化3 a;北大西洋大气要素变化对北大西洋热盐环流年代际振荡有非常重要的调制作用,当副极地流环和北大西洋暖流(NAC)达到最强的2 a之前,高纬度地区大气为气旋式环流异常,中纬度地区大气为反气旋式环流异常,海表热通量在大西洋副极地海区是负异常,这都有利于副极地流环和NAC的加强,更多高盐度的北大西洋水进入格陵兰-冰岛-挪威海(GIN)海域,由此可以导致GIN海域表层密度上升,使水体的层结稳定性减弱,有利于深层对流的发生,同时大气变化通过风应力旋度和海表热通量也直接影响GIN海域深层水的生成,进而导致格陵兰－苏格兰海脊溢流水的强度增加。  相似文献   

2010年以来华西秋季降水年代际增多原因初探          下载免费PDF全文

徐曼琳  周波涛  程志刚 《大气科学学报》2020,43(3):568-576

基于1961-2016年降水资料和NCEP/NCAR再分析数据,分析了华西秋季降水的年代际变化特征。结果表明,华西秋季降水在20世纪80年代中期前偏多,之后减少,21世纪10年代又开始增多,而且该时段的降水量多于20世纪80年代中期前。进一步从大气环流角度,初步探讨了这种年代际变化的成因。研究发现,与华西降水偏少阶段相比,在两个降水偏多期,巴尔喀什湖低压槽加深、亚洲区域海平面气压（Sea Level Pressure,SLP）负异常,利于高纬冷空气南下入侵华西区域;东亚低空盛行异常偏南风,利于低纬水汽向华西区域输送;东亚西风急流位置偏北,提供华西降水发生的动力抬升条件,共同造成华西秋季降水增加。相比于20世纪80年代前,21世纪10年代后欧洲高压脊和巴尔喀什湖槽更强,更利于高纬冷空气进入华西区域。同时,有来自南半球印度洋的水汽向华西区域输送。更强的冷空气活动和更多的水汽输送导致后一阶段降水更多。  相似文献   

近159年东亚夏季风年代际变化与中国东部旱涝分布(英文)     

李茜  魏凤英  李栋梁 《地理学报(英文版)》2011,21(4):579-593

Based on the drought/flood grades of 90 meterological stations over eastern China and summer average sea-level pressure (SLP) during 1850–2008 and BPCCA statistical methods, the coupling relationship between the drought/flood grades and the East Asian summer SLP is analyzed. The East Asian summer monsoon index which is closely related with interdecadal variation of drought/flood distribution over eastern China is defined by using the key areas of SLP. The impact of the interdecadal variation of the East Asian summer monsoon on the distribution of drought/flood over eastern China in the last 159 years is researched. The results show that there are four typical drought and flood spatial distribution patterns in eastern China, i.e. the distribution of drought/flood in southern China is contrary to the other regions, the distribution of drought/flood along the Huanghe River–Huaihe River Valley is contrary to the Yangtze River Valley and regions south of it, the distribution of drought/flood along the Yangtze River Valley and Huaihe River Valley is contrary to the other regions, the distribution of drought/flood in eastern China is contrary to the western. The main distribution pattern of SLP in summer is that the strength of SLP is opposite in Asian continent and West Pacific. It has close relationship between the interdecadal variation of drought/flood distribution patterns over eastern China and the interdecadal variation of the East Asian summer monsoon which was defined in this paper, but the correlation is not stable and it has a significant difference in changes of interdecadal phase. When the East Asian summer monsoon was stronger (weaker), regions north of the Yangtze River Valley was more susceptible to drought (flood), the Yangtze River Valley and regions south of it were more susceptible to flood (drought) before the 1920s; when the East Asian summer monsoon was stronger (weaker), the regions north of the Yangtze River Valley was prone to flood (drought), the Yangtze River Valley and regions south of it were prone to drought (flood) after the 1920s. It is indicated that by using the data of the longer period could get much richer results than by using the data of the last 50–60 years. The differences in the interdecadal phase between the East Asian summer monsoon and the drought/flood distributions in eastern China may be associated with the nonlinear feedback, which is the East Asian summer monsoon for the extrinsic forcing of solar activity.  相似文献   

Seasonal and lnterdecadal Variations of Heat Transport over the Northern Henfisphere     

《中国海洋大学学报(英文版)》2006,5(3):200-206

  相似文献   

Long-term variabilities of thermodynamic structure of the East China Sea Cold Eddy in summer   总被引：6，自引：0，他引：6  

陈永利  胡敦欣王凡 《中国海洋湖沼学报》2004,22(3):224-230

Based on more than 30 years observed sectional temperature data since the 1960s, and compared with multi-year wind and Changjiang (Yangtze) River discharge data, spatial-temporal variations of the East China Sea Cold Eddy (ECSCE) in summer was analyzed in relationship to ocean circulation and local atmospheric circulation. Empirical Orthogonal Function (EOF) and Singular Value Decomposition (SVD) analyseswere applied to this study. The results show that: l) The ECSCE in summer possesses significant interannual variabilities, which are directly associated with oceanic and atmospheric circulation anomaly. Main fluctuations demonstrate their falling in basically with E1 Nino events (interannual) and interdecadal variability. 2) The ECSCE in summer is closely related to the variation of the Yellow Sea Warm Current (YSWC) and the Changjiang River discharge. The stronger the YSWC, the more intensive the ECSCE with its center shifting westward,and vice versa. However, a negative correlation between the Changjiang River discharge and the ECSCE strength is shown. The ECSCE was strengthened after the abrupt global climate change affected by the interdecadal variation of the YSWC. 3) SVD analysis suggested a high correlation between the variation of the ECSCE in summer and the anomalous cyclonic atmospheric circulation over the ECS. Intensification of the cyclonic wind strengthens the ECSCE, and vice versa. 4) The cyclonic atmospheric circulation has dominant influence on the interannual variation of the ECSCE, and the influence of the ocean circulation takes the second in. The ECSCE was usually stronger in E1 Nifio years affected by strong cyclonic circulation in the atmosphere. The variation in strength of the ECSCE resulted from the joint effect of both oceanic and atmospheric circulation.  相似文献