1998年南海夏季风的爆发与大气季节内振荡的活动   总被引：42，自引：1，他引：41  

穆明权  李崇银 《气候与环境研究》2000,5(4):375-387

利用NCEP再分析及TBB资料,系统地研究了1998年南海夏季风爆发与大气季节内振荡活动的关系,结果表明,1998年南海夏季风爆发与南海及其临近地区30～60天低频振荡的发展有着极为密切的关系。南海及临近地区30～60天低频纬向风及低频动能的时间-经（纬）度剖面明显地反映出该地区的大气季节内振荡的加强是由于其临近地区（菲律宾以东）30～60天低频气旋发展及其向西扩展的结果,与孟加拉湾地区低频气旋的活动关系不大;同时,我们也看到了夏季风爆发前后南海地区为850hPa低频动能的大值区,而200hPa上为一弱区,反映了1998年南海夏季风爆发期间该地区大气季节内振荡有上弱下强的垂直分布特征。进一步分析表明,南海及其临近地区大气季节内振荡的活动主要为局地振荡型,夏季风爆发后才有明显的向北传播,成为南海夏季风爆发影响东亚大气环流和天气的重要途径之一。另外,1980和1986年南海地区30～60天低频动能的发展特征与1998年的类似,说明了南海及其临近地区大气季节内振荡的局地振荡特征并不是1998年所特有的,它对南海夏季风爆发有普遍的重要作用。  相似文献   

1998年夏季风爆发前后南海上混合层的特征及成因   总被引：8，自引：1，他引：7  

刘秦玉  贾旭晶  孙即霖  张秀芝 《气候与环境研究》2000,5(4):469-481

利用1998年“南海季风实验（SCSMEX）”南北部两个点的资料,采用J.Launianen和T.Vihma提出的方法,计算了潜热通量、感热通量和风应力,分析了南海上混合层动力、热力特征及其与南海夏季风爆发之间的关系。发现在西南季风爆发前后,南海北部、南部的两个观测点的海洋上混合层温度和深度随时间的变化具有不同的特点：北部混合层温度经历由高到低再变高,混合层深度经历由浅变深再变浅的3个时段;南部混合层温度经历由低到高再变低,混合层深度经历由深变浅再变深的3个时段。这与南海南、北部海面的风和海面热通量具备不同的特征有关。在5～6月南海上混合层动力、热力特征基本受局地风与短波辐射控制,海面潜热和感热的作用较小。在5月份,南海南部观测点海面附近存在浅薄的高盐高密度层,在60m以上的上层海洋内存在着许多高盐高密度核。在1998年“南海季风实验”期间南海南、北部两个观测点都存在较浅薄的障碍层,在西南季风爆发期间,南海北部观测点的障碍层较厚达到20m以上。  相似文献   

Simulations of the impact of orbital forcing and ocean on the Asian summer monsoon during the Holocene   总被引：3，自引：1，他引：2  

Yuefeng Li  Sandy P. Harrison   《Global and Planetary Change》2008,60(3-4):505-522

The importance of orbital forcing and ocean impact on the Asian summer monsoon in the Holocene is investigated by comparing simulations with a fully coupled ocean–atmosphere general circulation model (FOAM) and with the atmospheric component of this model (FSSTAM) forced with prescribed modern sea-surface temperatures (SSTs). The results show: (1) the ocean amplifies the orbitally-induced increase in African monsoon precipitation, makes somewhat increase in southern India and damps the increase over the southeastern China. (2) The ocean could change the spatial distribution and local intensity of the orbitally-induced latitudinal atmospheric oscillation over the southeastern China and the subtropical western Pacific Ocean. (3) The orbital forcing mostly enhances the Asian summer precipitation in the FOAM and FSSTAM simulations. However, the ocean reduces the orbitally-induced summer precipitation and postpones the time of summer monsoon onset over the Asian monsoon region. (4) The orbital forcing considerably enhances the intensity of upper divergence, which is amplified by ocean further, over the eastern hemisphere. But the divergence is weaker in the FOAM simulations than in the FSSTAM simulations when the orbital forcing is fixed. (5) The orbital forcing can enhance the amplitude of precipitation variability over the subtropical Africa, the southeastern China and northwestern China, inversely, reduce it over central India and North China in the FOAM and FSSTAM simulations. The ocean obviously reduces the amplitude of precipitation variability over most of the Asian monsoon regions in the fixed orbital forcing simulations. (6) The areas characterized by increased summer precipitation in the long-term mean are mostly characterized by increased amplitude of short-term variability, whereas regions characterized by decreased precipitation are primarily characterized by decreased amplitude of short-term variability. However, the influences of orbital forcing or dynamical ocean on regional climate depend on the model.  相似文献   

晚更新世以来长江三角洲长尺度气候干旱事件 ——来自沉积物环境磁学的记录     

周绮娴  杨小强  李剑  林清龙  彭杰  翁元忠  丁洁荧  刘春莲． 《热带地理》2016,36(3):427-437

选择位于长江三角洲南部区域的3个钻孔CSB4、CSB6和CSB8,开展环境磁学方面的研究,以揭示该地区晚更新世以来沉积物记录的显著气候事件。结果显示：3个钻孔都存在明显的S300低值区域,其变化规律为当S300为低值时,磁化率、ARM和SIRM的值较低,而IRMAF80mT/SIRM和ARM/SIRM的比值相对较高,表明磁性矿物浓度降低、粒度变细。同时S300低值区域沉积物以黄色粉砂质黏土为主,含铁锰质结核。IRM获得曲线定量分析结果揭示：沉积物中赤铁矿等高矫顽力组分的含量相对增加,指示长江三角洲区域3次显著的干旱气候事件。在磁性地层及其AMS 14C、光释光测年基础上,推断3次干旱事件发生的时间分别为163―121 ka B.P.（事件I）、57―42 ka B.P.（事件II）和14―10 ka B.P.（事件III）,对应海平面相对较低时期,季风减弱,降水减少,气候干旱,形成以氧化作用为主的环境。  相似文献   

Effects of spectral nudging on the 2010 East Asia summer monsoon using WRF model     

单海霞  管玉平  黄建平 《中国海洋湖沼学报》2012,30(6):1105-1115

The performance of spectral nudging in an investigation of the 2010 East Asia summer monsoon was assessed using the Weather Research and Forecasting (WRF) model, forced by 1-degree NCEP Global Final Analysis (FNL). Two pairs of experiments were made, spectral nudging (SP) and non-spectral nudging (NOSP), with five members in each group. The members were distinguished by different initial times, and the analysis was based on the ensemble mean of the two simulation pairs. The SP was able to constrain error growth in large-scale circulation in upper-level, during simulation, and generate realistic regional scale patterns. The main focus was the model ability to simulate precipitation. The Tropical Rainfall Measuring Mission (TRMM) 3B42 product was used for precipitation verification. Mean precipitation magnitude was generally overestimated by WRF. Nevertheless, SP simulations suppressed overestimation relative to the NOSP experiments. Compared to TRMM, SP also improved model simulation of precipitation in spatial and temporal distributions, with the ability to reproduce movement of rainbands. However, extreme precipitation events were suppressed in the SP simulations.  相似文献   

Interannual variations of surface winds over China marginal seas     

孙澈  闫晓梅 《中国海洋湖沼学报》2012,30(6):922-932

In a study of surface monsoon winds over the China marginal seas, Sun et al. (2012) use singular value decomposition method to identify regional dominant modes and analyze their interdecadal variability. This paper continues to evaluate the interannual variability of each dominant mode and its relation to various atmospheric, oceanic and land factors. The findings include: 1) The intensity of the winter monsoon over the East China Sea is highly correlated with the Siberian High intensity and anti-correlated with the latitudinal position of the Aleutian Low as well as the rainfall in eastern China, Korean Peninsula and Japan; 2) The western Pacific subtropical high is significantly correlated with the summer monsoon intensity over the East China Sea and anti-correlated with the summer monsoon over the South China Sea; 3) The winter monsoon in a broad zonal belt through the Luzon Strait is dominated by the ENSO signal, strengthening in the La Ni a phase and weakening in the El Ni o phase. This inverse relation exhibits interdecadal shift with a period of weak correlation in the 1980s; 4) Analysis of tidal records validates the interdecadal weakening of the East Asian summer monsoon and reveals an atmospheric bridge that conveys the ENSO signal into the South China Sea via the winter monsoon.  相似文献   

Geochemistry of rare earth elements in the mid-late Quaternary sediments of the western Philippine Sea and their paleoenvironmental significance     

XU ZhaoKai  LI TieGang  WAN ShiMing  YIN XueBo  JIANG FuQing  SUN HanJie  JinYong CHOI & DhongIl LIM 《中国科学:地球科学(英文版)》2014,57(4):802-812

Based on a δ18O chronology,rare earth elements(REE) and other typical elements in sediments from core MD06-3047 in the western Philippine Sea were analyzed to constrain the provenances of the sediments and investigate quantitative changes in the Asian eolian input to the study area over the last 700 ka.Among the competing processes that might affect REE compositions,sediment provenance is the most important one.Provenance analysis suggests that the study sediments have two provenance end-members;local volcanic sources are dominant,and eolian dust from the Asian continent has a smaller contribution.During glacial periods,eolian input to the western Philippine Sea was enhanced.In contrast,material supply from local volcanics increased during interglacial periods.Changes in eolian input to the study area were probably related to the strength of the East Asian winter monsoon(EAWM) as well as aridity in the Asian continent on an orbital time scale,and were partly influenced by local control factors on shorter time scales.Therefore,we propose that the present study expands the application of the REE-based method for quantitatively estimating the eolian component from the mid-latitude northern Pacific to the low-latitude western Pacific.Additionally,the study preliminarily confirms the influence of EAWM-transported eolian material on sedimentation in the western Philippine Sea since 700 ka.  相似文献   

Design and testing of a global climate prediction system based on a coupled climate model   总被引：3，自引：0，他引：3  

JieHua Ma  HuiJun Wang 《中国科学:地球科学(英文版)》2014,57(10):2417-2427

A global climate prediction system(PCCSM4) was developed based on the Community Climate System Model, version 4.0, developed by the National Center for Atmospheric Research(NCAR), and an initialization scheme was designed by our group. Thirty-year(1981–2010) one-month-lead retrospective summer climate ensemble predictions were carried out and analyzed. The results showed that PCCSM4 can efficiently capture the main characteristics of JJA mean sea surface temperature(SST), sea level pressure(SLP), and precipitation. The prediction skill for SST is high, especially over the central and eastern Pacific where the influence of El Ni?o-Southern Oscillation(ENSO) is dominant. Temporal correlation coefficients between the predicted Ni?o3.4 index and observed Ni?o3.4 index over the 30 years reach 0.7, exceeding the 99% statistical significance level. The prediction of 500-hPa geopotential height, 850-hPa zonal wind and SLP shows greater skill than for precipitation. Overall, the predictability in PCCSM4 is much higher in the tropics than in global terms, or over East Asia. Furthermore, PCCSM4 can simulate the summer climate in typical ENSO years and the interannual variability of the Asian summer monsoon well. These preliminary results suggest that PCCSM4 can be applied to real-time prediction after further testing and improvement.  相似文献   

Strengthened Regulation of the Onset of the South China Sea Summer Monsoon by the Northwest Indian Ocean Warming in the Past Decade     

Yang AI  Ning JIANG  Weihong QIAN  Jeremy Cheuk-Hin LEUNG  Yanying CHEN 《大气科学进展》2022,39(6):943-952

Traditionally,a delayed(early)onset of the South China Sea summer monsoon(SCSSM)has been observed to follow a warm(cold)El Ni?o-Southern Oscillation(ENSO)event in winter,supporting high seasonal predictability of SCSSM onset.However,the empirical seasonal forecasting skill of the SCSSM onset,solely based on ENSO,has deteriorated since 2010.Meanwhile,unexpected delayed onsets of the SCSSM have also occurred in the past decade.We attribute these changes to the Northwest Indian Ocean(NWIO)warming of the sea surface.The NWIO warming has teleconnections related to(1)suppressing the seasonal convection over the South China Sea,which weakens the impacts of ENSO on SCSSM onset and delays the start of SCSSM,and(2)favoring more high-frequency,propagating moist convective activities,which enhances the uncertainty of the seasonal prediction of SCSSM onset date.Our results yield insight into the predictability of the SCSSM onset under the context of uneven ocean warming operating within the larger-scale background state of global climate change.  相似文献   

气候变化对中国东部季风区水资源脆弱性的影响评价   总被引：3，自引：0，他引：3  

夏军  雒新萍  曹建廷  陈俊旭  宁理科  洪思 《气候变化研究进展》2015,11(1):8-14

将耦合暴露度、灾害风险、敏感性与抗压性的脆弱性评估模型应用于中国东部季风区水资源脆弱性评价,从水资源供需平衡角度分析了气候变化对东部季风区水资源脆弱性的影响。结果表明,2000年气候条件下,我国东部季风区接近90%的区域水资源处于中度脆弱及以上状态。其中水资源中度和高度脆弱区域约占全区的75%,极端脆弱区域接近15%。中国北方海河、黄河、淮河和辽河流域的水资源脆弱性最高。未来气候变化影响将加剧水资源脆弱性的风险,不同RCP排放情景下2030年代我国东部季风区水资源中度脆弱及以上区域面积有明显的扩大,极端脆弱区域将达到20%～25%。由于未来需水的进一步增加,中国北方水资源脆弱性的格局并未发生根本变化,而南方东南诸河等区域将面临可能发生的水危机。  相似文献