武威地区冬季低温天气的气候分析与预报

通过对１９８０—１９９１年１２—２月武威地区低温天气过程气候特征和天气成因的分析，建立模式预报方程。１９９２—１９９６年试报效果良好，将植入“武威地区冬半年寒潮降温多目标专家系统”，投入业务运行。     

北京地区大气环流型及气候特征

以北京地区为研究对象,应用Lamb-Jenkinson大气环流分型方法对1948-2008年的逐日平均海平面气压场进行定量计算环流指数。通过对27类逐日环流分型结果的统计分析得出：北京地区主导环流类型依次为A型、C型和SW型,其频率分别为23.8 %、15.4%和7.0%;A和C环流型频率均呈逐年上升趋势,但A型频率上升速度远大于C型;春季北京主导环流类型为A型和C型,夏季主导环流型为C型和SW型,夏季CSW型环流所占比例也较大,秋季和冬季为A型。通过主导环流型和北京气温、降水之间变化规律的分析可知：冬季在A型环流的控制下北京地区多为低温晴好天气;夏季在C型环流的控制下北京地区降水增多,在SW型环流的控制下北京地区降水偏少,而CSW型环流控制下北京地区呈现干热天气状态,2000年后尤为明显。     

1969—2008年海南省雾的气候特征与变化趋势

利用海南省1969—2008年观测资料,对海南雾的时空分布气候特征及变化趋势进行分析,并利用观测的最低气温、相对湿度资料和NCEP/NCAR再分析资料对海南雾日数变化的成因加以分析。结果表明,海南雾日数在中部山区出现最多,其次是北部地区,南半部沿海地区则极少有雾出现;雾主要出现在9月至翌年3月,年雾日数呈减少趋势;最低气温升高是引起雾日数减少的主要原因,雾日数的减少与相对湿度的减小也是一致的;秋冬和初春季节夜间气温低,有利于雾的形成;海拔越高的地区,气温越低,则生成的雾越多;雾日数显著偏多年份850hPa大陆高压偏弱,偏少年份偏强;雾日数显著偏多年份500hPa西太平洋副高强度偏弱,范围偏小,偏少年份则相反。     

内蒙古高温酷暑天气的气候学特征和环流类型

利用1971—2008年内蒙古117个观测站日最高气温资料,结合同期的NCEP再分析资料,分析了内蒙古高温酷暑天气的气候学特征。结果表明:内蒙古高温酷暑天气地域差异大,高温中心在阿拉善盟沙漠地区的拐子湖,年平均35℃高温日数达32天,也是全国的高温区之一;内蒙古的高温天气年日数有增长趋势,高温酷暑的影响在增强;内蒙古高温酷暑集中出现在盛夏季节6—8月,7月发生最多,占一半以上;最高气温出现在每日的14—17时,气温日较差大,多为干热天气。通过对内蒙古较大范围的64次高温天气过程分析总结,将内蒙古高温酷暑天气分为蒙古暖脊型、贝加尔湖高压坝型、副高西进型、乌拉尔山高脊型4个类型。大陆暖高压脊的强烈发展和维持与内蒙古高温酷暑天气密切相关。     

Objective Identification and Climatic Characteristics of Heavy-Precipitation Northeastern China Cold Vortexes

The northeastern China cold vortex(NCCV) plays an important role in regional rainstorms over East Asia. Using the National Centers for Environmental Prediction Final reanalysis dataset and the Global Precipitation Measurement product,an objective algorithm for identifying heavy-precipitation NCCV(HPCV) events was designed, and the climatological features of 164 HPCV events from 2001 to 2019 were investigated. The number of HPCV events showed an upward linear trend, with the highest frequency of ...     

各种大气水汽输送气候计算方法的比较和讨论

比较瞬时法，平均法和逐层平均法３种水汽输送气候计算方案，发现它们的输送方向大致相同，输送量差异显著。瞬时法最准确；逐层平均法次之，但误差的年际波动较大，平均法虽然简单然而误差大。     

A New Scheme for Predicting Leaf Onset in Summer-Green Vegetation in the Northern Hemisphere

A modified thermal time model(MTM) was developed to reproduce the leaf onset for summer-green vegetation in the Northern Hemisphere. The model adopts the basic concept of a thermal time model(TM) in that leaf onset is primarily triggered by growing degree days(GDD). Based on global phenology data derived from satellite observations, a new parameterization for the critical model parameter Tb(i.e., baseline temperature for GDD calculation) has been introduced, and the spatial distribution of Tb was calculated. Simulations of leaf onset during 1982–2000 in the range 30–90°N showed a significant improvement of MTM over the standard TM model with constant Tb. The mean error and mean absolute error of the climatological simulation were 1.11 and 6.8 days, respectively, and 90% of the model error(5th and 95 th percentiles) was between-12.4 and 13.7 days.     

Distinguished Effects of Interannual Salinity Variability on the Development of the Central-Pacific El Nino Events

El Nio events in the central equatorial Pacific (CP) are gaining increased attention,due to their increasing intensity within the global warming context.Various physical processes have been identified in the climate system that can be responsible for the modulation of El Nio,especially the effects of interannual salinity variability.In this work,a comprehensive data analysis is performed to illustrate the effects of interannual salinity variability using surface and subsurface salinity fields from the Met Office ENSEMBLES (EN3) quality controlled ocean dataset.It is demonstrated that during the developing phase of an El Nio event,a negative sea surface salinity (SSS) anomaly in the western-central basin acts to freshen the mixed layer (ML),decrease oceanic density in the upper ocean,and stabilize the upper layers.These related oceanic processes tend to reduce the vertical mixing and entrainment of subsurface water at the base of the ML,which further enhances the warm sea surface temperature (SST) anomalies associated with the El Nio event.However,the effects of interannually variable salinity are much more significant during the CP-El Nio than during the eastern Pacific (EP) El Nio,indicating that the salinity effect might be an important contributor to the development of CP-El Nio events.     

NCEP 全球预报系统在ARM SGP站点预报大气温度、湿度和云量的检验

利用美国大气辐射测量项目(ARM)制作的“气候模拟最佳估计”(CMBE)观测数据集,检验美国环境预报中心(NCEP)全球预报系统(GFS)2001～2008年在ARM Southern Great Plains(SGP)站点预报的大气温度、相对湿度和云量的垂直分布,主要结论如下:(1)NCEP GFS较好地预报出了温度...     

昌吉市太阳总辐射的气候学计算及其变化特征分析

利用昌吉市1961—1997年的逐日气候资料,对昌吉市1961—1997年多年平均逐日太阳总辐射进行了气候学计算,并分析了其变化特征和变化趋势,结果表明:昌吉市太阳总辐射多年平均年日总量为22.82MJ.m-2.d-1,太阳总辐射在8～9月份最高,12月份最低,昌吉市的太阳总辐射呈逐年下降趋势。