DIFFERENCES OF SOUTH CHINA SEA SUMMER MONSOON DERIVED BY NCEP AND ECMWF REANALYSIS DATA     

ZHENG Bin  GU De-jun  LI Chun-hui 《热带气象学报(英文版)》2006,12(2):197-200

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与华北干旱相关联的全球尺度气候变化现象   总被引：12，自引：1，他引：11  

黄刚 《气候与环境研究》2006,11(3):270-279

利用ERA-40再分析资料集的风、温度、水汽等再分析资料,分析了华北地区干旱以及北非萨赫勒地区干旱化的气候特征及它们之间的关联,指出在亚非季风区上空存在一个年代际的季风环流异常遥相关波列,正是由于此波列的作用,使得我国华北地区从1965年以后所发生的干旱与北非萨赫勒地区干旱化存在着明显的相关联.并且分析了这两地区的干旱与之相关联的全球气候变化背景,指出由于1965年之后北、南半球气温变化差异的减少导致了亚非季风系统发生了年代际减弱和南撤,从而使得华北和北非萨赫勒地区发生了持续干旱现象.    相似文献   

黄河上游径流丰枯变化特征及其环流背景   总被引：7，自引：4，他引：3  

蓝永超  沈永平  林纾  张世强  畅俊杰 《冰川冻土》2006,28(6):950-955

为了揭示影响黄河上游径流丰枯变化的气候因子,为径流的长期、超长期预报与水资源的规划利用提供依据,利用相关台站的降水、径流观测资料,分析了黄河上游汛期径流的丰枯变化特征及其环流背景.结果表明:黄河上游(唐乃亥以上)流域丰、枯水段基本上是交替出现的,总体上枯水持续时间多于丰水,一个完整的丰枯循环周期大约在18 a左右.黄河上游径流的丰、枯,与大气环流的异常有着非常密切的关系,其中,西太平洋副热带高压偏西、偏强、偏北,青藏高原中部地区有西风槽存在是黄河上游汛期降水偏多、径流偏丰的两个重要因素.因此,基于汛期流量的丰枯与其所对应的环流背景之间的联系,可根据前期环流的演变特征对黄河上游汛期流量的丰枯做出大致预测.  相似文献   

南海北部1144站中更新世浮游有孔虫的千年尺度古气候记录     

郑范  李前裕  陈木宏 《地球科学》2006,31(6):780-786

南海北部ODP1144站中更新世气候转型时期的浮游有孔虫在千年尺度上以高频率变化为主要特征.冰期旋回主要周期在0.9Ma由41ka转变为100ka, 浮游有孔虫组合也随冰期旋回出现大量的冷水种.据转换函数得出的表层水降温高达10℃发生在0.9~0.6Ma间的转型过渡期, 跨越MIS22、20、18、16四大冰期.同时, 温跃层深度呈阶梯式变浅, 在MIS20上升至65m左右.所以, 南海北部上层水体环境在中更新世气候转型期出现比末次冰期更重的δ18O值, 温跃层变浅, 深水种含量降低或消失, 突出了边缘海区南北气候梯度反差和冬季风在冰期增强的讯号.南海南北部的环境差异与东西太平洋的差异, 共同表明低纬过程在气候变化中的重要性.   相似文献   

Spatio-temporal variability in sea surface wind stress near and off the east coast of Korea   总被引：1，自引：1，他引：0  

NAM SungHyun  KIM Young Ho  PARK Kyung-Ae  KIM Kuh 《海洋学报(英文版)》2005,24(1):107-114

Sea surface wind stress variabilities near and off the east coast of Korea, are examined using 7 kinds of wind datasets from measurements at 2 coastal (land) stations and 2 ocean buoys,satellite scatterometer (QuikSCAT), and global reanalyzed products (ECMWF,NOGAPS,and NCEP/NCAR). Temporal variabilities are analyzed at 3 frequency bands; synoptic (2-20 d), intra-seasonal (20-90 d),and seasonal (>90 d).Synoptic and intra-seasonal  相似文献   

Formation of the Waiho Loop terminal moraine,New Zealand          下载免费PDF全文

DAVID ALEXANDER  TIMOTHY DAVIES  JAMES SHULMEISTER 《第四纪科学杂志》2014,29(4):361-369

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Tracing the boundary layer sources of carbon monoxide in the Asian summer monsoon anticyclone using WRF-Chem   总被引：1，自引：0，他引：1  

Renchang Yan  Jianchun Bian 《大气科学进展》2015,32(7):943-951

The Asian summer monsoon(ASM) anticyclone is a dominant feature of the circulation in the upper troposphere–lower stratosphere(UTLS) during boreal summer, which is found to have persistent maxima in carbon monoxide(CO). This enhancement is due to the upward transport of air with high CO from the planetary boundary layer(PBL), and confinement within the anticyclonic circulation. With rapid urbanization and industrialization, CO surface emissions are relatively high in the ASM region, especially in India and East China. To reveal the transport pathway of CO surface emissions over these two regions, and investigate the contribution of these to the CO distribution within the ASM anticyclone, a source sensitivity experiment was performed using the Weather Research and Forecasting(WRF) with chemistry model(WRFChem). According to the experiment results, the CO within the ASM anticyclone mostly comes from India, while the contribution from East China is insignificant. The result is mainly caused by the different transportation mechanisms. In India,CO transportation is primarily affected by convection. The surface air with high CO over India is directly transported to the upper troposphere, and then confined within the ASM anticyclone, leading to a maximum value in the UTLS region. The CO transportation over East China is affected by deep convection and large-scale circulation, resulting mainly in transportation to Korea, Japan, and the North Pacific Ocean, with little upward transport to the anticyclone, leading to a high CO value at215 h Pa over these regions.  相似文献   

2014年夏季我国气候异常及成因简析   总被引：6，自引：4，他引：2  

崔童  王东阡  李多  孙丞虎  李清泉  王遵娅 《气象》2015,41(1):121-125

2014年夏季,全国平均气温为21．1℃,较常年同期偏高0．2℃。全国平均降水量为320．1 mm,较常年同期偏少1．6％,空间分布呈现北少南多的显著特征,其中黄淮地区平均降水量与1999年并列历史同期最少。进一步对2014年夏季我国降水异常成因分析表明,东亚夏季风偏弱及西北太平洋副热带高压偏强、偏南是造成我国夏季降水北少南多的直接原因;印度洋海温偏暖和厄尔尼诺状态共同作用导致副热带高压持续偏强偏南;两者是造成降水异常的重要外强迫条件。  相似文献   

一次低槽冷锋层状云系结构和过冷水分布特征的模拟研究   总被引：1，自引：1，他引：0  

刘涛  孙晶  周毓荃  彭冲  闫非 《气象》2015,41(10):1232-1244

本文利用耦合了CAMS云微物理方案的WRF中尺度模式的模拟结果结合飞机、卫星、雷达、地面雨量等观测资料,对2012年9月25日山西一次低槽弱冷锋降水层状云系的宏微观结构和过冷水分布特征进行分析,试图研究低槽冷锋层状云系结构特征及过冷水形成的宏微观条件,为人工增雨作业提供依据。模拟的天气形势、降水、云顶温度、雷达回波、水成物的演变与实测基本一致。结果表明：此次降水过程的系统为低槽弱冷锋,且锋面后倾,位于锋前的云系前部为高层冷云,云顶温度-40℃左右,以冰相粒子组成,没有降水;锋区云系变成高层冷暖混合云,冷区以少量过冷水和大量冰相粒子组成,地面降水最大;处于锋后的云系后部为高层冷云,云顶温度-30℃左右,不存在过冷水,以较少冰相粒子组成,地面降水较弱。过冷水主要分布在锋面前方低于-5℃层,高度偏低、含量偏少,过冷水一方面因垂直上升速度供应水汽维持,另一方面因冰相粒子的凝华而消耗。过冷水层及其下部上升运动较弱、而其上部上升运动较强,不利于在过冷区长时间维持大量液态水,反而促使冰相粒子发展旺盛,此处水汽相对水面不饱和、相对冰面饱和,大量冰相粒子消耗水汽,不利于过冷水的存在,导致云场仅存在少量过冷水。本次过程中,冰核浓度的增大仅增大冰晶浓度,对雪霰含量及-5~0℃的过冷水几乎没有影响。  相似文献   

Sensitivity of Precipitation over China to Different Cumulus Parameterization Schemes in RegCM4          下载免费PDF全文

ZHANG Shaobo  L&#; Shihu  BAO Yan  MA Di 《Acta Meteorologica Sinica》2015,29(1):119-131

The effect of different cumulus parameterization schemes(CPSs) on precipitation over China is investigated by using the International Centre for Theoretical Physics(ICTP) Regional Climate Model version 4.3(Reg CM-4.3) coupled with the land surface model BATS1e(Biosphere-Atmosphere Transfer Scheme version1e). The ERA-interim data are utilized to drive a group of simulations over a 31-yr period from September1982 to December 2012. Two typically sensitive regions, i.e., the eastern Tibetan Plateau(TP; 29°–38°N,90°–100°E) and eastern China(EC; 26°–32°N, 110°–120°E), are focused on. The results show that all the CPSs have well reproduced the spatial distribution of annual precipitation in China. The simulation with the Emanuel scheme shows an overall overestimation of precipitation in China, different from the other three CPSs which only overestimate over northern and northwestern China but underestimate over southern China. Seasonally, the Tiedtke scheme shows the smallest overestimation in winter and summer, and the best simulation of the annual variance of precipitation. Interannual variations of precipitation among the four CPSs are generally simulated better in summer than in winter, and better for entire China than in the subregions of TP and EC. The precipitation trend is simulated better over EC than over TP, and better in summer than in winter. An overestimate(underestimate) of the East Asian summer monsoon index(EASMI) exists in the simulations with the Grell and the Emanuel(the Kuo and the Tiedtke) schemes.The smallest EASMI bias in the Tiedtke simulation could explain its small precipitation bias. A negative correlation between the EASMI and summer precipitation over the middle and lower reaches of Yangtze River is found in the Grell and the Emanuel simulations, but was missed by the simulations using the Kuo and the Tiedtke schemes.  相似文献