Possible Sources of Forecast Errors Generated by the Global/Regional Assimilation and Prediction System for Landfalling Tropical Cyclones. Part Ⅱ: Model Uncertainty

This paper investigates the possible sources of errors associated with tropical cyclone (TC) tracks forecasted using the Global/Regional Assimilation and Prediction System (GRAPES). In Part I, it is shown that the model error of GRAPES may be the main cause of poor forecasts of landfalling TCs. Thus, a further examination of the model error is the focus of Part II. Considering model error as a type of forcing, the model error can be represented by the combination of good forecasts and bad forecasts. Results show that there are systematic model errors. The model error of the geopotential height component has periodic features, with a period of 24 h and a global pattern of wavenumber 2 from west to east located between 60°S and 60°N. This periodic model error presents similar features as the atmospheric semidiurnal tide, which reflect signals from tropical diabatic heating, indicating that the parameter errors related to the tropical diabatic heating may be the source of the periodic model error. The above model errors are subtracted from the forecast equation and a series of new forecasts are made. The average forecasting capability using the rectified model is improved compared to simply improving the initial conditions of the original GRAPES model. This confirms the strong impact of the periodic model error on landfalling TC track forecasts. Besides, if the model error used to rectify the model is obtained from an examination of additional TCs, the forecasting capabilities of the corresponding rectified model will be improved.     

江西强雷电天气形势场及雷达回波特征分析

利用常规天气资料、地面观测资料、江西WebGIS雷达拼图和雷电监测资料,对2014—2016年江西出现的22次强雷电天气过程进行统计和对比分析。结果表明:江西强雷电天气易出现在赣北北部、南昌附近、上饶地区和吉安西部等区域;强雷电天气出现的环境背景场可分为副热带高压边缘型、副热带高压控制型、低涡切变型和台风外围型,最显著的特征是中高空经常伴有干冷舌侵入低层暖湿区;多项对流指数可以预测出现强雷电天气的可能性;雷达回波和雷电强度关系密切,回波类型以带状和块状为主;雷电强度和雷达回波强度有很好的对应关系,但产生强雷电的回波要具备强度大于50 dBz、强回波中心密实、强回波边缘梯度大等条件。     

t-BAMBP/磺化煤油萃取体系从盐湖卤水中萃取铷的动力学研究

采用上升单液滴法,进行盐湖卤水中萃取铷的动力学研究,主要考察了比界面积、水相铷浓度和油相(t-BAMBP/磺化煤油)浓度对萃取速率的影响。通过比界面积的研究发现,t-BAMBP萃取铷的过程由界面化学反应和相内化学反应共同控制;通过对实验数据的非线性拟合,得到了萃取体系的动力学方程,R=9.936×10-7[Rb+]1.134[t-BAMBP]2.190,萃取速率对铷的反应级数为a=1.134,对t-BAMBP反应级数b=2.190,实验值和计算值的均方根误差为1.735%。     

Sensitivity of Potential Evapotranspiration Estimation to the Thornthwaite and Penman–Monteith Methods in the Study of Global Drylands

Drylands are among those regions most sensitive to climate and environmental changes and human-induced perturbations.The most widely accepted definition of the term dryland is a ratio,called the Surface Wetness Index(SWI),of annual precipitation to potential evapotranspiration(PET)being below 0.65.PET is commonly estimated using the Thornthwaite(PET Th)and Penman–Monteith equations(PET PM).The present study compared spatiotemporal characteristics of global drylands based on the SWI with PET Th and PET PM.Results showed vast differences between PET Th and PET PM;however,the SWI derived from the two kinds of PET showed broadly similar characteristics in the interdecadal variability of global and continental drylands,except in North America,with high correlation coefficients ranging from 0.58 to 0.89.It was found that,during 1901–2014,global hyper-arid and semi-arid regions expanded,arid and dry sub-humid regions contracted,and drylands underwent interdecadal fluctuation.This was because precipitation variations made major contributions,whereas PET changes contributed to a much lesser degree.However,distinct differences in the interdecadal variability of semi-arid and dry sub-humid regions were found.This indicated that the influence of PET changes was comparable to that of precipitation variations in the global dry–wet transition zone.Additionally,the contribution of PET changes to the variations in global and continental drylands gradually enhanced with global warming,and the Thornthwaite method was found to be increasingly less applicable under climate change.     

基岩地区地源热泵系统浅层地热地质条件评估工作方法

在北京地区建设地源热泵系统之前,需要开展浅层地热地质条件评估,以作为政府部门为地源热泵系统立酉备案的必要的技术文件,是一项专业前期可行性研究工作。其评估工作方法和内容,在基岩地区和第四系松散沉积区应有很大的不同。在基岩地区应倜重于野外实地调查,包括填制工作区地质图、工作区岩石特征,岩石完整性调查和水井普测等;并通过充分的资料收集和必要的勘查手段,查明工作区地层、岩石、构造等地质条件,特别是划分构造带、构造影响带范围,进而判断换热孔钻遇地层的可钻性和换热能力,进行相关技术和经济分析及评价。     

El Ni?o对东亚夏季风和夏季降水季节内变化的影响

基于1979~2012年候平均再分析资料,合成分析了El Ni?o对东亚夏季风和夏季降水季节内变化的影响。结果表明,在El Ni?o衰减年夏季,西太平洋副热带高压(副高)明显偏强,位置偏向西南。副高的这种异常特征随夏季的季节进程有明显变化,初夏异常较弱,盛夏期间异常达到最强。此外,根据东亚夏季风降水呈现阶段式北进的特征,将夏季分为华南前汛期、江淮梅雨期、华北和东北雨期以及华南后汛期来分析东亚夏季风和降水的季节内变化。在上述各个时期,大气对流层低层表现为一致的环流异常型,副高及其以南区域为异常反气旋,其北部为异常气旋。这种异常环流型加强了副高南部偏东风及其北部偏北风,增强了热带水汽输送和高纬度地区冷空气的入侵,二者结合造成主汛期地区降水增加。需要强调的是,上述环流异常型随东亚夏季风逐步向北推移,导致东亚各地区的主汛期降水增加,非主汛期降水减少,降水分布更为集中。     

柴达木盆地西部中生界原型盆地恢复

勘探实践表明,对柴达木盆地西部中生界原型盆地认识不够,是导致该区侏罗系油气勘探难以取得重大突破的主要原因。以古流分析为主要手段,结合地表露头及地震解释资料研究认为,中生界在古阿拉巴斯套山与古昆仑山间发育一个大的近EW向展布的内陆山间坳陷（古泛茫崖坳陷）。坳陷演化可分为早—中侏罗世和晚侏罗世—白垩纪两个阶段,分别对应发育了伸展断陷和挤压坳陷两种原型盆地类型。早、中侏罗世,阿尔金山尚未隆升,为主要沉积区。沉积环境比较动荡,沉积物以暗色含煤建造为主。沉积中心在现今的阿尔金山区,坳陷西北部边界越过阿尔金山区与塔东南地区相通;东北部边界位于阿拉巴斯套山前;南部边界在煤沟—采石岭—黑石山—月牙山一线。晚侏罗世—白垩纪,阿尔金山快速隆升为物源区,开始分割塔东南和柴达木盆地西部沉积。坳陷沉积物以干旱气候下的红色粗碎屑岩建造为主,沉积、沉降中心由阿尔金山区向盆地内部发生迁移,南部边界已迁移至阿拉尔—红柳泉—红沟子—月3井一带。该研究对柴达木盆地资源潜力评价及勘探部署具有重要意义。     

计算机信息系统雷电防护技术初探

在分析计算机信息系统遭受雷击损害原因的基础上,结合多年的实践经验,提出了计算机信息系统雷电防护的具体措施。认为计算机信息系统的雷电防护应作为系统工程来考虑,要强调全面防护、综合治理。在具体的防护技术上,应采用“躲-分流-均压-屏蔽-接地”系统,以防止雷电及雷电电磁脉冲危害,并有效地解决雷电磁兼容性问题。     

云南8月气温与春季气温场的典型相关分析

利用典型相关理论,分析了云南８月低温与当年春季气温场之间的关系,得出了一些有意义的结果。春季影响云南的西风带南支槽、副热带高压和北方南下冷空气等天气系统的强弱（南支槽的强和弱用滇西气温的负距平和正距平表示,副热带高压的强和弱用滇东南气温的正距平和负距平表示,冷空气的强和弱用滇东气温的负距平和正距平表示）与８月份云南是否出现低温天气关系较大,８月份云南北部和西部出现低温天气与２月份冷空气和南支槽的强     

中国北方黄土高原地区黄土的微结构模型(详细摘要)

试样为取自中国北方黄土高原标准剖面^①中的马兰(Q₃)、离石(Q₂)、午城(Q₁)以及次生的洪积-冲积(Q₄)黄土.各方面成功的配合与多手段的综合性研究使我们能对黄土的微结构模型有了概念,能分析结构特征对黄土某些性质的影响,并可用来解释已提出的有关成因的一些看法.