我国中部地区夏季干旱的多时间尺度特征及其环流、海温异常     

赵昶昱  陈海山  孙善磊 《气象科学》2019,39(3):386-395

基于CRU逐月降水和NCEP/NCAR再分析等资料,利用集合经验模态分解(Ensemble Empirical Mode Decomposition,EEMD)方法,分析1948—2016年中国中部地区夏季降水变化的多时间尺度特征及其对应的环流、海温异常,进而解释不同时期影响干旱发生的背景场有何不同。结果表明,中部地区夏季降水以年际变化为主,周期长度为3.8 a和6.9 a,年代际和多年代际变化的方差贡献不足20%。然而,各时间尺度降水变化对不同时期干旱事件的贡献存在较大差异,1960s、1970s,降水年际变化偏弱,相反地,多年代际变化正处于负位相的极小值期;1980s、1990s,多年代际变化位相转正;2000s初,年际变化明显增强。此外,通过分析不同时间尺度降水变化对应的环流、海温背景场,发现热带印度洋海温异常及其引起的西北太平洋副热带高压的变化、大西洋北部海温异常激发的纬向波列以及贝加尔湖地区的阻塞活动、1970s末PDO位相转变伴随的东亚夏季风突变是分别解释降水年际、年代际和多年代际变化的主要原因,进而揭示影响中部地区夏季干旱发生的关键因子及其相对重要性。  相似文献   

INFLUENCE OF SPRING EQUATORIAL EASTERN PACIFIC SSTA ON THE SEASONAL CHANGE FROM SPRING TO SUMMER OF EASTERN ASIAN CIRCULATION     

彭加毅  孙照渤  王元 《热带气象学报(英文版)》2002,8(1):37-43

Based on the analysis of NCEP height, wind and OLR data, the influence of spring equatorial eastern Pacific SSTA on the seasonal change from spring to summer of eastern Asian circulation has been investigated. Results show that related to the warm (cold) spring SSTA in the equatorial eastern Pacific, the anomalous anticyclone (cyclone) circulation emerges around the South China Sea and the Philippines, the strong (weak) west Pacific subtropical high locates to the west (east) of its normal position, which induces to the late (early) onset of the South China Sea monsoon. The numerical simulations have also shown that the remarkable influence of spring SSTA in the equatorial eastern Pacific on the spring seasonal change of eastern Asian circulation will last till summer.  相似文献   

河套地区一次明显降水环流成因分析     

王敏芝  薛德友  白贤利 《内蒙古气象》2011,(2):18-20

利用常规的气象资料,针对河套地区2009年5月的一次明显降水过程,分别从水汽来源、环境场、环流背景、水汽条件和动力条件方面进行了详细的分析。  相似文献   

GCF-1500冲击反循环工程钻机   总被引：3，自引：0，他引：3  

喻重山 《煤田地质与勘探》1999,27(6):65-66

介绍了ＧＣＦ—１５００ 冲击反循环工程钻机的技术参数和性能特点。钻机采用了冲击反循环方式,钻进效率高,适应地层面广。  相似文献   

Diagnostic study on seasonality and interannual variability of wind field   总被引：9，自引：0，他引：9  

Xue Feng  Zeng Qingcun 《大气科学进展》1999,16(4):537-543

l.Intr0ductionThoughseasonalvariationoftheatmosphericgeneralcirculationismainlycausedbythatofthesolarradiation,itsdistributionsareinhomogeneousovertheglobe,forinstance,itismoresignificantinmonsoonregionthaninanyotherregions.Inatraditionalsense,mon-soonsummarisesalldrasticseasonalvariationsinthetropicsandsubtropics(e.g.,IndiaandEastAsia).Besidestheclassicmonsoonregions,thereexistsomeotherregionsovertheglobe,wheretheseasonalvariationisclearorevendrastic.Inordertodescribequantitativelysea-sonal…  相似文献   

The Role of diabatic heating, torques and stabilities in forcing the radial- vertical circulation within cyclones part iii: case study of lee-side cyclones     

Donald R. Johnson  Zhuojian Yuan 《大气科学进展》1999,16(1):31-63

１．ＩｎｔｒｏｄｕｃｔｉｏｎＡｎａｇｒｅｅｍｅｎｔｂｅｔｗｅｅｎｔｈｅｓｉｍｕｌａｔｅｄａｎｄ“ｏｂｓｅｒｖｅｄ”ａｚｉｍｕｔｈａｌｙ－ａｖｅｒａｇｅｄｍａｓ－ｗｅｉｇｈｔｅｄｒａｄｉａｌｍｏｔｉｏｎｓｈａｓｂｅｎｅｓｔａｂｌｉｓｈｅｄｆｏｒｔｈｅＯ...  相似文献   

Numerical simulation of the regional ocean circulation in the coastal areas of china   总被引：3，自引：0，他引：3  

Zhang Yaocun  Qian Yongfu 《大气科学进展》1999,16(3):443-450

The regional ocean circulation in the coastal areas or China (including a part of the western Pacific Ocean, the South China Sea and the Bay of Bengal el al.) is simulated by using the improved Princeton Uni-versity ocean circulation model (POM). Compared with the modeling results obtained by the large-scale ocean general circulation model (OGCM), the basic ocean circulation features simulated by the regional ocean circulation model are in good agreement with that simulated by OGCM and some detailed character-istics such as the regional ocean circulation, sea temperature, salinity and free sea surface height have also been obtained which are in good accord with the observations. These results indicate that the regional ocean circulation model has good capability to produce the regional ocean circulation characteristics and it can be used to develop coupled regional ocean-atmospheric model systems.  相似文献   

铁路几种类型的便线设计及测量要素的计算方法     

廖小年  齐华 《四川测绘》1999,22(3):123-127

本文在介绍铁路便线的设计过程中,详细地讨论了各类曲线测量要素的计算方法,掌握了这些方法,铁路便线施工放样的困难就可迎刃而解。  相似文献   

NJ150型冲击钻在钻探漂石层中的应用     

叶英标 《地质与勘探》1999,35(4):62-62,F003

通过工程实例,阐述了ＮＪ１５０型冲击凿井机有钻探漂石层中得到应用,成功地解决了这个问题,它是长螺旋钻孔压浆桩钻探施工的一个补充,同时,它也改变了该钻机不能通过漂石层的原设计性能,拓宽了应用范围。  相似文献   

Contrasts between the Interannual Variations of Extreme Rainfall over Western and Eastern Sichuan in Mid-summer     

Mengyu DENG  Riyu LU  Chaofan LI 《大气科学进展》2022,39(6):999-1011

Rainfall amount in mid-summer(July and August)is much greater over eastern than western Sichuan,which are characterized by basin and plateau,respectively.It is shown that the interannual variations of extreme rainfall over these two regions are roughly independent,and they correspond to distinct anomalies of both large-scale circulation and sea surface temperature(SST).The enhanced extreme rainfall over western Sichuan is associated with a southward shift of the Asian westerly jet,while the enhanced extreme rainfall over eastern Sichuan is associated with an anticyclonic anomaly in the upper troposphere over China.At low levels,on the other hand,the enhanced extreme rainfall over western Sichuan is related to two components of wind anomalies,namely southwesterly over southwestern Sichuan and northeasterly over northeastern Sichuan,which favor more rainfall under the effects of the topography.Relatively speaking,the enhanced extreme rainfall over eastern Sichuan corresponds to the low-level southerly anomalies to the east of Sichuan,which curve into northeasterly anomalies over the basin when they encounter the mountains to the north of the basin.Therefore,it can be concluded that the topography in and around Sichuan plays a crucial role in inducing extreme rainfall both over western and eastern Sichuan.Finally,the enhanced extreme rainfall in western and eastern Sichuan is related to warmer SSTs in the Maritime Continent and cooler SSTs in the equatorial central Pacific,respectively.  相似文献