印度洋偶极子研究进展综述   总被引：10，自引：2，他引：8  

肖莺  张祖强  何金海 《热带气象学报》2009,25(5):621-627

印度洋偶极子（IOD）是影响亚洲气候异常的重要系统之一。自1999年IOD提出以来,国内外学者对其形成机理及其与ENSO相互作用的研究取得了很大进展。综述了近年来国内外学者关于印度洋偶极子的定义、时空分布特征、形成机理、与ENSO的关系、对东亚气候的影响等问题的研究成果,提出了目前该领域存在的科学问题。  相似文献   

有限区域流函数和速度势的3种求解方法在分析台风Bilis暴雨增幅中的比较研究     

任晨平  曹洁  王黎娟  崔晓鹏 《气候与环境研究》2013,18(6):721-732

将有限区域流函数、速度势求解中常用的两种张驰法(即理查逊法和加速利布曼法)与调和—余弦谱展开法(H-C法)进行了比较,理论研究表明:H-C法单独考虑边界影响分量,物理意义明确,且不会丢失边界上的天气系统;从计算上看,H-C法重建的风场能精确还原原始风场,且计算效率明显高于两种张驰法,即收敛更快。通过在台风Bilis(0604)暴雨增幅过程诊断中的应用发现,常用的两种张驰迭代方法在求解有限区域流函数和速度势的问题上效果都不是很好,即:用理查逊法和加速利布曼法计算的流函数和速度势重建的风场与原始风场差别较大,不能准确还原原始风场;用H-C法不仅计算效率高,还原的风场与原始风场差异极小,且不受南边界较强的西南季风涌影响,在暴雨增幅前期能较好地反映与暴雨增幅相关的强辐合信号。因此,可用H-C法计算得到的无辐散风和无旋风对有限区域的天气系统进行更深入的动力结构分析。  相似文献   

Simulated Change in the Interannual Variability of South Asian Summer Monsoon in the 21st Century   总被引：1，自引：0，他引：1  

FU Yuanhai  LU Riyu 《大气科学进展》2010,27(5):992-1002

This study investigates the projected changes in interannual variability of South Asian summer monsoon and changes of ENSO-monsoon relationships in the 21st century under the Intergovernmental Panel on Climate Change (IPCC) scenarios A1B and A2, respectively, by analyzing the simulated results of twelve Coupled Model Intercomparison Project Phase 3 (CMIP3) coupled models. The dynamical monsoon index (DMI) was adopted to describe the interannual variability of South Asian summer monsoon, and the standard dev...  相似文献   

Interdecadal Variability of East Asian Summer Monsoon Precipitation over 220 Years （1777-1997）   总被引：1，自引：1，他引：0  

Chun-Ji KIM  QIAN Weihong  Hyun-Suk KANG  Dong-Kyou LEE 《大气科学进展》2010,27(2):253-264

In this study, long-term (1777–1997) precipitation data for Seoul, Korea, wetness indices from eastern China, and modern observations are used to identify the interdecadal variability in East Asian summer monsoon precipitation over the last 220 years. In the East Asian monsoon region, two long-term timescales of dry–wet transitions for the interdecadal variability and quasi-40-and quasi-60-year timescales are dominant in the 220-year precipitation data of Seoul, as well as in the wetness indices over China....  相似文献   

Relationship between East Asian Monsoon and Dust Weather Frequency over Beijing   总被引：1，自引：0，他引：1  

WU Yunfei  ZHANG Renjian  HAN Zhiwei  ZENG Zhaomei 《大气科学进展》2010,27(6):1389-1398

The relationship between dust weather frequency (DWF), which denotes the number of days of dust weather events, over Beijing and the East Asian Monsoon (EAM) was studied using DWF data for Beijing during the period 1951--2006. Results show that, during this period, the blowing-dust weather frequency (BDWF), as well as the indices of East Asian winter monsoon (EAWM) and East Asian summer monsoon (EASM), all decreased considerably, with a t-test confidence level of 99%. The correlation coefficients between the chosen EAWM index and BDWF over Beijing in winter and the following spring were 0.34 and 0.33, respectively, with significance levels of 0.01 and 0.02, respectively. For the chosen EASM index and BDWF, these correlation coefficients were 0.51 and 0.45, respectively, with both at a confidence level exceeding 99.9%. With the linear trends removed, the values (in the same order as above) were 0.14, 0.14, -0.12, and -0.09, all not significant at the 95% confidence level. Clearly, the EAM relates mainly to DWF over long timescales. To a certain extent, the EAM might have some impact on DWF by affecting the associated surface air temperature and precipitation during the corresponding time period in sand-dust source regions at the interannual scale. A stronger (weaker) EAWM might advance (suppress) the occurrence of DWF, and the opposite for the EASM.  相似文献   

A Study on Water Vapor Transport and Budget of Heavy Rain in Northeast China   总被引：1，自引：0，他引：1  

SUN Li  SHEN Baizhu  SUI Bo 《大气科学进展》2010,27(6):1399-1414

The characteristics of moisture transport and budget of widespread heavy rain and local heavy rain events in Northeast China are studied using the NCEP--NCAR reanalysis 6-hourly and daily data and daily precipitation data of 200 stations in Northeast China from 1961--2005. The results demonstrate that during periods with widespread heavy rain in Northeast China, the Asian monsoon is very active and the monsoonal northward moisture transport is strengthened significantly. The widespread heavy rainfall obtains enhanced water vapor supply from large regions where the water vapor mainly originates from the Asian monsoon areas, which include the East Asian subtropical monsoon area, the South China Sea, and the southeast and southwest tropical monsoon regions. There are several branches of monsoonal moisture current converging on East China and its coastal areas, where they are strengthened and then continue northward into Northeast China. Thus, the enhanced northward monsoonal moisture transport is the key to the widespread heavy rain in Northeast China. In contrast, local heavy rainfall in Northeast China derives water vapor from limited areas, transported by the westerlies. Local evaporation also plays an important role in the water vapor supply and local recycling process of moisture. In short, the widespread heavy rains of Northeast China are mainly caused by water vapor advection brought by the Asian monsoon, whereas local heavy rainfall is mainly caused by the convergence of the westerly wind field.  相似文献   

近45年华中地区不同级别强降水事件变化趋势   总被引：7，自引：2，他引：5       下载免费PDF全文

陈波  史瑞琴  陈正洪 《应用气象学报》2010,21(1):47-54

利用华中五省84个测站1961—2005年逐日降水资料,通过分位值法、趋势系数法、蒙特卡洛统计检验法、曼-肯德尔法、小波分析等现代统计诊断方法,分析了华中地区不同级别强降水的时空变化趋势、突变和周期特征。结果表明:随着分位值减小,降水量、日数的平均值和均方差逐渐减小,变差系数逐渐增大;而强度的3项指标均逐渐增大;在空间分布上,降水量自河南向湖南和江西逐渐增大;日数自北向南逐渐增大;强度以湖北东部至江西北部的长江中下游一线以及湖南西北部局部地区为高值区;区域平均的降水量、日数和强度均呈增加趋势,但不同测站表现不同;降水量一致在1993年发生突变,呈增多趋势;日数在20世纪80年代末、90年代初发生突变;强度自1994年开始增强,21世纪后加强、减弱现象交替出现;降水量、日数和强度有12~14年的年代际变化和6~9年的短期变化。  相似文献   

Source identification of PM_2.5 particles measured in Gwangju, Korea   总被引：1，自引：0，他引：1  

Hanlim Lee  Seung S. Park  Kyung W. Kim  Young J. Kim   《Atmospheric Research》2008,88(3-4):199-211

The UNMIX and Chemical Mass Balance (CMB) receptor models were used to investigate sources of PM_2.5 aerosols measured between March 2001 and February 2002 in Gwangju, Korea. Measurements of PM_2.5 particles were used for the analysis of carbonaceous species (organic (OC) and elemental carbon (EC)) using the thermal manganese dioxide oxidation (TMO) method, the investigation of seven ionic species using ion chromatography (IC), and the analysis of twenty-four metal species using Inductively Coupled Plasma (ICP)-Atomic Emission Spectrometry (AES)/ICP-Mass Spectrometry (MS). According to annual average PM_2.5 source apportionment results obtained from CMB calculations, diesel vehicle exhaust was the major contributor, accounting for 33.4% of the measured PM_2.5 mass (21.5 μg m^− 3), followed by secondary sulfate (14.6%), meat cooking (11.7%), secondary organic carbon (8.9%), secondary nitrate (7.6%), urban dust (5.5%), Asian dust (4.4%), biomass burning (2.8%), sea salt (2.7%), residual oil combustion (2.6%), gasoline vehicle exhaust (1.9%), automobile lead (0.5%), and components of unknown sources (3.4%). Seven PM_2.5 sources including diesel vehicles (29.6%), secondary sulfate (17.4%), biomass burning (14.7%), secondary nitrate (12.6%), gasoline vehicles (12.4%), secondary organic carbon (5.8%) and Asian dust (1.9%) were identified from the UNMIX analysis. The annual average source apportionment results from the two models are compared and the reasons for differences are qualitatively discussed for better understanding of PM_2.5 sources.Additionally, the impact of air mass pathways on the PM_2.5 mass was evaluated using air mass trajectories calculated with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) backward trajectory model. Source contributions to PM_2.5 collected during the four air mass patterns and two event periods were calculated with the CMB model and analyzed. Results of source apportionment revealed that the contribution of diesel traffic exhaust (47.0%) in stagnant conditions (S) was much higher than the average contribution of diesel vehicle exhaust (33.4%) during the sampling period. During Asian dust (AD) periods when the air mass passed over the Korean peninsula, Asian dust and secondary organic carbon accounted for 25.2 and 23.0% of the PM_2.5 mass, respectively, whereas Asian dust contributed only 10.8% to the PM_2.5 mass during the AD event when the air mass passed over the Yellow Sea. The contribution of biomass burning to the PM_2.5 mass during the biomass burning (BB) event equaled 63.8%.  相似文献   

Compositions and source apportionments of atmospheric aerosol during Asian dust storm and local pollution in central Taiwan     

Man-Ting Cheng  Wei-Chun Chou  Chia-Pin Chio  Shih-Chieh Hsu  Yi-Ru Su  Pei-Hsuan Kuo  Ben-Jei Tsuang  Shuen-Hsin Lin  Charles C.-K. Chou 《Journal of Atmospheric Chemistry》2008,61(2):155-173

A study has been carried out on water soluble ions, trace elements, as well as PM_2.5 and PM_2.5–10 elemental and organic carbon samples collected daily from Central Taiwan over a one year period in 2005. A source apportionment study was performed, employing a Gaussian trajectory transfer coefficient model (GTx) to the results from 141 sets of PM_2.5 and PM_2.5–10 samples. Two different types of PM₁₀ episodes, local pollution (LOP) and Asian dust storm (ADS) were observed in this study. The results revealed that relative high concentrations of secondary aerosols (NO₃⁻, SO₄²⁻ and NH₄⁺) and the elements Cu, Zn, Cd, Pb and As were observed in PM_2.5 during LOP periods. However, sea salt species (Na⁺ and Cl⁻) and crustal elements (e.g., Al, Fe, Mg, K, Ca and Ti) of PM_2.5–10 showed a sharp increase during ADS periods. Anthropogenic source metals, Cu, Zn, Cd, Pb and As, as well as coarse nitrate also increased with ADS episodes. Moreover, reconstruction of aerosol compositions revealed that soil of PM_2.5–10 elevated approximately 12–14% in ADS periods than LOP and Clear periods. A significantly high ratio of non-sea salt sulfate to elemental carbon (NSS-SO₄²⁻/EC) of PM_2.5–10 during ADS periods was associated with higher concentrations of non-sea-salt sulfates from the industrial regions of China. Source apportionment analysis showed that 39% of PM₁₀, 25% of PM_2.5, 50% of PM_2.5–10, 42% of sulfate and 30% of nitrate were attributable to the long range transport during ADS periods, respectively.  相似文献   

Interdecadal change in the connection between Hadley circulation and winter temperature in East Asia   总被引：5，自引：0，他引：5  

周波涛  王会军 《大气科学进展》2008,25(1):24-30

Based on NCEP/NCAR reanalysis data, the interdecadal variability of Hadley circulation （HC） and its association with East Asian temperature in winter are investigated. Results indicate that the Northern Hemisphere winter HC underwent apparent change in the 1970s, with transition occurring around 1976/77. Along with interdecadal variability of HC, its linkage to surface air temperature （SAT） in East Asia also varied decadally, from weak relations to strong relations. Such a change may be related to the interaction between HC and the atmospheric circulation system over the Philippines, which is associated with the East Asian winter monsoon （EAWM）. Before the 1970s, the connection between HC and the anticyclonic circulation around the Philippines was insignificant, but after the late 1970s their linkage entered a strong regime. The intensification of this connection may therefore be responsible for the strong relations between HC and East Asian winter temperatures after the late 1970s.  相似文献