共查询到20条相似文献，搜索用时 343 毫秒
1.
西北太平洋热带气旋源地变化特征及与局地海表温度的关系 总被引：2，自引：0，他引：2
为提高热带气旋的短期气候预测水平,利用1950-2005年西北太平洋热带气旋(TC)和表层水温(SST)资料,分析了西北太平洋TC生成位置分布的一般气候特征,季节、年际变化特征及其与局地SST之间的关系,同时还探讨了TC强度、路径与TC生成位置之间的关系.结果表明,西北太平洋存在4个TC高频源地,分别是南海中北部偏东洋面、菲律宾以东附近洋面、关岛附近洋面和马绍尔群岛附近洋面,其中关岛附近洋面TC发生数最多,是TC发生的一个主要源地.TC生成位置分布存在显著的季节和年际变化特征,这种变化与局地SST存在密切的关系,局地SST升高,TC生成位置偏西、偏北,反之,则偏东、偏南.同时发现,TC生成位置西北边界与月平均SST的27.5℃等温线具有较好的匹配关系,绝大多数TC都发生在月平均SST≥27.5℃的海区.TC强度、路径与TC生成位置之间存在一定的关系.TC生成位置偏东偏南,其发展强度相对较强,路径偏东偏南,可导致影响我国南部海区和日本东部沿海的TC个数增加;TC生成位置偏西偏北,其发展强度相对较弱,路径偏西北,可导致影响我国东部和北部沿海的TC个数增加. 相似文献
2.
3.
A review of seasonal climate prediction research in China 总被引：9，自引：0，他引：9
WANG Huijun FAN Ke SUN Jianqi LI Shuanglin LIN Zhaohui ZHOU Guangqing CHEN Lijuan LANG Xianmei LI Fang ZHU Yali CHEN Hong ZHENG Fei 《大气科学进展》2015,32(2):149-168
4.
Weijie FENG Marco Y.-T. LEUNG Dongxiao WANG Wen ZHOU Oscar Y. W. ZHANG 《大气科学进展》2022,39(10):1637-1649
An extreme drought appeared in South China from October 2020 to March 2021. During that time, sea surface temperatures exhibited an unprecedented warm center over the northwest Pacific (NWP) and a cold center over the tropical eastern Pacific (La Ni?a). This study demonstrates the combined effects of an exceptionally warm NWP and a moderate La Ni?a are closely linked to the anomalous drought in South China. The sea surface temperature anomaly in these two regions induced a steeper horizontal geopotential height gradient over South China. As a result, anomalous northeasterly winds prevailed over South China, altering water vapor transport and moisture convergence. A simplified atmospheric general circulation model also verifies the influence of the NWP warm anomaly on South China precipitation. This study points out that the sea surface temperature variation in the NWP was important to the occurrence of extreme drought in South China from October 2020 to March 2021. 相似文献
5.
A possible linkage in the interdecadal variability of rainfall over North China and the Sahel 总被引：8，自引：0，他引：8
1. Introduction The capital city of China, Beijing, and other largecities, such as Tianjin and Shijiazhuang are all locatedin North China (roughly the region 35?–40?N, 110?–125?E), a region with a very large population. In thepast several decades, the rainfall decreased remarkablyin North China. Nevertheless, the amount of waterdemanded by agriculture and industry and the popu-lation at large has increased. These two trends havemade the de?ciency of water resources in North Chinabeco… 相似文献
6.
G. R. Weber 《Theoretical and Applied Climatology》1994,50(1-2):15-22
Summary At Berlin-Dahlem, monthly single station data on cloudiness, sunshine duration, mean, maximum and minimum temperature is statistically analyzed for the time period 1955–1993.It is found that sunshine duration varies inversely with cloud cover; cloud cover correlates negatively with temperature range. Cloud cover correlates negatively with temperature between March and September, and positively with temperature during the remaining months.Between 1955 und 1993, there are no significant changes in temperature range in any month but June and September, when a decline occurred.Sunshine declined significantly in March, June and September. Trends between 1955 and 1987 indicate a larger decline of sunshine and decline in temperature range than between 1955 and 1993.Locally, sulfate deposition, which may be taken as an indicator of the atmospheric sulfate load, decreased by more than a third between the mid-1950s and the late 1980s. Therefore, at Berlin, the observed increase of cloudiness (decrease of sunshine duration) between the 1950s and the late 1980s went parallel to the measured decrease of sulfate deposition.With 3 Figures 相似文献
7.
Arti B. Bandgar J. S. Chowdary C. Gnanaseelan 《Theoretical and Applied Climatology》2014,118(1-2):69-79
The Northwest Pacific (NWP) circulation (subtropical high) is an important component of the East Asian summer monsoon system. During summer (June–August), anomalous lower tropospheric anticyclonic (cyclonic) circulation appears over NWP in some years, which is an indicative of stronger (weaker) than normal subtropical high. The anomalous NWP cyclonic (anticyclonic) circulation years are associated with negative (positive) precipitation anomalies over most of Indian summer monsoon rainfall (ISMR) region. This indicates concurrent relationship between NWP circulation and convection over the ISMR region. Dry wind advection from subtropical land regions and moisture divergence over the southern peninsular India during the NWP cyclonic circulation years are mainly responsible for the negative rainfall anomalies over the ISMR region. In contrast, during anticyclonic years, warm north Indian Ocean and moisture divergence over the head Bay of Bengal-Gangetic Plain region support moisture instability and convergence in the southern flank of ridge region, which favors positive rainfall over most of the ISMR region. The interaction between NWP circulation (anticyclonic or cyclonic) and ISMR and their predictability during these anomalous years are examined in the present study. Seven coupled ocean–atmosphere general circulation models from the Asia-Pacific Economic Cooperation Climate Center and their multimodel ensemble mean skills in predicting the seasonal rainfall and circulation anomalies over the ISMR region and NWP for the period 1982–2004 are assessed. Analysis reveals that three (two) out of seven models are unable to predict negative (positive) precipitation anomalies over the Indian subcontinent during the NWP cyclonic (anticyclonic) circulation years at 1-month lead (model is initialized on 1 May). The limited westward extension of the NWP circulation and misrepresentation of SST anomalies over the north Indian Ocean are found to be the main reasons for the poor skill (of some models) in rainfall prediction over the Indian subcontinent. This study demonstrates the importance of the NWP circulation variability in predicting summer monsoon precipitation over South Asia. Considering the predictability of the NWP circulation, the current study provides an insight into the predictability of ISMR. Long lead prediction of the ISMR associated with anomalous NWP circulation is also discussed. 相似文献
8.
随着数值预报技术的飞速发展, 模式定量降水预报已成为天气预报业务工作中的主要参考依据。本文对目前在国家气象中心应用的3个业务运行模式T213L31, HLAFS0.25, 华北中尺度模式MM5和德国模式及日本模式的降水预报产品进行了季节空间分布、区域时间序列演变及统计检验, 试图从空间、时间及统计方面对降水预报产品的预报性能进行综合评估。检验结果表明:目前的数值预报模式对短期时效内定量降水预报均具有一定的空间预报能力, 但强降水中心位置有一定的偏差; 从时间序列演变检验来看, 模式对区域强降水过程的发展趋势具有较强的预报能力, 但降水量预报与实况有一定的差距; 从累加统计评分检验结果来看, 模式短期时效的预报性能差别不大, 全球模式在小中雨预报方面有一定优势, 其中日本模式的综合预报性能最好, 大雨以上量级的预报则是国内的模式有一定的优势, 其中华北中尺度MM5模式, T213L31模式各有所长, 但均存在预报量和预报区偏大问题。 相似文献
9.
近57a夏季西太平洋副高面积的年代际振荡及其与中国降水的联系 总被引：4，自引：0，他引：4
利用1951—2007年NCEP/NCAR再分析资料及中国国家气候中心160站降水和环流特征指数,研究了近57 a来夏季平均的西太平洋副热带高压面积指数的气候变化特征及其对同期中国降水的影响。结果表明,在全球变暖的气候背景下,夏季副热带高压面积也表现出增大趋势,其中20世纪60年代中期和20世纪末显著增强,并呈现出准20 a的年代际周期变化特征。各周期中,中国同期降水及流场均出现较大调整：随着西太平洋副热带高压面积长期趋于增大,东亚夏季风异常偏弱,降水分布由＂北多南少＂转为＂北少南多＂,而降水线性增长的区域则呈现出较上一周期明显北移的特征。 相似文献
10.
China's Feng Yun 3(FY-3) polar orbiting satellites are set to become an important source of observational data for numerical weather prediction(NWP),atmospheric reanalyses,and climate monitoring studies over the next two decades.As part of the Climate Science for Service Partnership China(CSSP China) program,FY-3 B Microwave Humidity Sounder 1(MWHS-1) and FY-3 C MWHS-2 observations have been thoroughly assessed and prepared for operational assimilation.This represents the first time observations from China's polar orbiting satellites have been used in the UK's global NWP model.Since 2016,continuous data quality monitoring has shown occasional bias changes found to be correlated to changes in the energy supply scheme regulating the platform heating system and other transient anomalies.Nonetheless,MWHS-1 and MWHS-2 significantly contribute to the 24-h forecast error reduction by 0.3% and 0.6%,respectively,and the combination of both instruments is shown to improve the fit to the model background of independent sounders by up to 1%.The observations from the Microwave Radiation Imager(MWRI) also are a potentially significant source of benefits for NWP models,but a solar-dependent bias observed in the instrument half-orbits has prevented their assimilation.This paper presents the bases of a correction scheme developed at the Met Office for the purpose of a future assimilation of MWRI data. 相似文献
11.
Climatic regime shift and decadal anomalous events in China 总被引：15，自引：0，他引：15
Climatic time series from historical documents and instrumental records from China showed temporal and regional patterns in
the last two to three centuries, including two multidecadal oscillations at quasi-20-year and quasi-70-year timescales revealed
by signal analysis from wavelet transform. Climatic anomalous events on the decadal timescale were identified based on the
two oscillations when their positive (or negative) phases coincide with each other to amplify amplitude. The coldest event
occurred in the decade of 1965–1975 in eastern China, while the periods of 1920–1930, 1940–1950, and 1988–2000 appeared to
be warmer in most parts of China. For the precipitation series in northern China, the dry anomalous event was found in the
late 1920s, while the wet anomalous event occurred in the 1950s. A severe drought in 1927–1929 in northern China coincided
with the anomalous warm and dry decade, caused large-scale famine in nine provinces over northern China. Climatic anomalous
events with a warm-dry or cold-wet association in the physical climate system would potentially cause severe negative impacts
on natural ecosystem in the key vulnerable region over northern China. The spatial pattern of summer rainfall anomalies in
the eastern China monsoon region showed an opposite variations in phase between the Yellow River Valley (North China) and
the mid-low Yangtze River Valley as well as accompanied the shift of the northernmost monsoon boundary. Climatic regime shifts
for different time points in the last 200 years were identified. In North China, transitions from dry to wet periods occurred
around 1800, 1875, and 1940 while the transitions from wet to dry periods appeared around 1840, 1910, and the late 1970s.
The reversal transition in these time points can also be found in the lower Yangtze River. Climatic regime shifts in China
were linked to the interaction of mid- and low latitude atmospheric circulations (the westerly flow and the monsoon flow)
when they cross the Tibetan Plateau in East Asia. 相似文献
12.
With temperatures increasing as a result of global warming,extreme high temperatures are becoming more intense and more frequent on larger scale during summer in China.In recent years,a variety of researches have examined the high temperature distribution in China.However,it hardly considers the variation of temperature data and systems when defining the threshold of extreme high temperature.In order to discern the spatio-temporal distribution of extreme heat in China,we examined the daily maximum temperature data of 83 observation stations in China from 1950 to 2008.The objective of this study was to understand the distribution characteristics of extreme high temperature events defined by Detrended Fluctuation Analysis(DFA).The statistical methods of Permutation Entropy(PE)were also used in this study to analyze the temporal distribution.The results showed that the frequency of extreme high temperature events in China presented 3 periods of 7,10—13 and 16—20 years,respectively.The abrupt changes generally happened in the 1960s,the end of 1970s and early 1980s.It was also found that the maximum frequency occurred in the early 1950s,and the frequency decreased sharply until the late 1980s when an evidently increasing trend emerged.Furthermore,the annual averaged frequency of extreme high temperature events reveals a decreasing-increasing-decreasing trend from southwest to northeast China,but an increasing-decreasing trend from southeast to northwest China.And the frequency was higher in southern region than that in northern region.Besides,the maximum and minimum of frequencies were relatively concentrated spatially.Our results also shed light on the reasons for the periods and abrupt changes of the frequency of extreme high temperature events in China. 相似文献
13.
数值天气预报业务模式现状与展望 总被引：36，自引：5，他引：31
20 0 4年是数值天气预报理论提出 10 0周年 ,同时也是数值天气预报业务化应用 5 0周年。经过百年的发展历程 ,数值天气预报学科有了飞跃的发展。特别是最近 10多年来 ,大气科学以及地球科学的研究进展 ,高速度、大容量的巨型计算机及网络系统的快速发展 ,更加快了数值天气预报的发展步伐。文中从模式动力框架、物理过程参数化、模式程序软件等方面对数值天气预报业务模式现状进行了简要综述 ,对存在的问题进行了探讨 ,并对数值天气预报业务模式的未来发展作了展望。当前数值天气预报业务模式发展的特点有 :(1) 2 0世纪 90年代中期以来 ,各国的全球和区域模式水平和垂直分辨率都有明显提高 ,且模式物理过程也同步进行改进 ;数值预报业务模式已进入了大规模并行计算的阶段 ;(2 )主要发达国家和中国都正在致力于研发各自的新业务数值预报模式———非静力 (多尺度 )一体化模式或非静力中尺度模式 ,部分国家的新一代天气 气候一体化数值模式已业务运行 ;(3)业务数值预报模式正在朝着不断完善的方向发展。随着模式分辨率的提高 ,云物理过程、陆面过程和湍流过程、考虑坡度 -坡向因子的辐射过程等在模式中的参数化方案 ,以及模式垂直坐标的选择越来越受重视 ,这些物理过程的描述成为业务数值模式改进的重点和 相似文献
14.
15.
利用1949—2009年热带气旋降水资料分析了全国热带气旋降水的时空分布特征。结果表明,全国各地区热带气旋降水的空间分布很不均匀,大致呈现东南—西北向的梯度分布,东南沿海地区降水量最大,西北内陆地区最小。另外,地形对降水的空间分布也有影响,例如东南沿海和山脉迎风坡的地形作用尤为显著。此外,比较不同年份的热带气旋降水的空间分布特征,有很多相似之处,如随经纬度的变化趋势,降水最大中心位置等。热带气旋降水具有比较明显的年代变化和显著的年际震荡。年代变化表现为20世纪50—60年代为大幅增加的过程,60—80年代降水总量基本维持,80年代后期降水呈现明显的震荡趋势。 相似文献
16.
17.
概要介绍最近5年在国家科技攻关项目“中国气象数值预报系统科技创新研究”框架内所取得的主要成果，重点是卫星等遥感资料在变分同化中的应用，高分辨非静力数值预报模式的发展，全球资料同化与中期数值天气预报系统的发展，数值天气预报系统的模块化与并行计算，数值天气预报新技术的研究等，并扼要介绍我国新一代数值天气预报系统的业务应用试验。最后，对我国数值天气预报的进一步发展做了讨论。 相似文献
18.
近10年我国数值天气预报的进展(1980-1989) 总被引：3，自引：0，他引：3
对近十年来我国的数值天气预报工作进行了回顾和分析。还对这时期前后的工作进行了比较。从中可以看出,我国数值天气预报的进展是巨大的。还估计了我国和世界先进水平之间的差距,并提出了应采取的措施。 相似文献
19.
Sangwook Park Dong-Joon Kim Seung-Woo Lee Kie-Woung Lee Jongkhun Kim Eun-Ji Song Kyong-Hwan Seo 《Asia-Pacific Journal of Atmospheric Sciences》2017,53(3):393-401
This article describes a three way inter-comparison of forecast skill on an extended medium-range time scale using the Korea Meteorological Administration (KMA) operational ensemble numerical weather prediction (NWP) systems (i.e., atmosphere-only global ensemble prediction system (EPSG) and ocean-atmosphere coupledEPSG) and KMA operational seasonal prediction system, the Global Seasonal forecast system version 5 (GloSea5). The main motivation is to investigate whether the ensemble NWP system can provide advantage over the existing seasonal prediction system for the extended medium-range forecast (30 days) even with putting extra resources in extended integration or coupling with ocean with NWP system. Two types of evaluation statistics are examined: the basic verification statistics - the anomaly correlation and RMSE of 500-hPa geopotential height and 1.5-meter surface temperature for the global and East Asia area, and the other is the Real-time Multivariate Madden and Julian Oscillation (MJO) indices (RMM1 and RMM2) - which is used to examine the MJO prediction skill. The MJO is regarded as a main source of forecast skill in the tropics linked to the mid-latitude weather on monthly time scale. Under limited number of experiment cases, the coupled NWP extends the forecast skill of the NWP by a few more days, and thereafter such forecast skill is overtaken by that of the seasonal prediction system. At present stage, it seems there is little gain from the coupled NWP even though more resources are put into it. Considering this, the best combination of numerical product guidance for operational forecasters for an extended medium-range is extension of the forecast lead time of the current ensemble NWP (EPSG) up to 20 days and use of the seasonal prediction system (GloSea5) forecast thereafter, though there exists a matter of consistency between the two systems. 相似文献
20.
The upper-ocean responses to Typhoon Megi(2010)are investigated using data from ARGO floats and the satellite TMI.The experiments are conducted using a three-dimensional Princeton Ocean Model(POM)to assess the storm,which affected the Northwest Pacific Ocean(NWP)and the South China Sea(SCS).Results show that the upwelling and entrainment experiment together account for 93% of the SST anomalies,where typhoon-induced upwelling may cause strong ocean cooling.In addition,the anomalous SST cooling is stronger in the SCS than in the NWP.The most striking feature of the ocean response is the presence of a two-layer inertial wave in the SCS—a feature that is absent in the NWP.The near-inertial oscillations can be generated as typhoon wakes,which have maximum flow velocity in the surface mixed layer and may last for a few days,after the typhoon's passage.Along the typhoon tracks,the horizontal currents in the upper ocean show a series of alternating negative and positive anomalies emanating from the typhoon. 相似文献