共查询到19条相似文献，搜索用时 125 毫秒
1.
《干旱气象》2016,(5)
基于欧洲中期天气预报中心(ECMWF)逐日海平面气压场(MSLP)再分析资料和山东省122个台站逐日降水资料,采用Lamb-Jenkinson大气环流分型方法,将1958—2013年逐日海平面气压场分型,分析不同时间尺度下影响山东省的主要大气环流型出现频率分布特征,对山东省夏季降水与大气环流型关系进行初步研究,给出夏季各类环流型降水概率、降水强度及降水贡献率的时间变化特征。结果表明:(1)山东省全年主要环流型为SW、NE、A、SE、S、NW、N和C型;(2)8种主要环流型中,NE、NW、A和N型的出现频率在夏季为"低谷期",冬季为"高峰期",而SW、SE、C和S型则与之相反;(3)S、SE、SW、C型是夏季主要降水环流型,但是某些较为少见的环流型出现时,出现降水的概率非常大,可以为预报员提供参考;(4)夏季4种主要降水环流型的降水贡献率时间变化特征存在明显差异,S型和SE型呈现准周期振荡,SW型自1980年代以后持续降低,2011年以来仅为4%左右,为历史最低;1970年代以来,C型降水贡献率持续增加,由不足10%增至21%。 相似文献
2.
以北京地区为研究对象,应用Lamb-Jenkinson大气环流分型方法对1948-2008年的逐日平均海平面气压场进行定量计算环流指数。通过对27类逐日环流分型结果的统计分析得出：北京地区主导环流类型依次为A型、C型和SW型,其频率分别为23.8 %、15.4%和7.0%;A和C环流型频率均呈逐年上升趋势,但A型频率上升速度远大于C型;春季北京主导环流类型为A型和C型,夏季主导环流型为C型和SW型,夏季CSW型环流所占比例也较大,秋季和冬季为A型。通过主导环流型和北京气温、降水之间变化规律的分析可知：冬季在A型环流的控制下北京地区多为低温晴好天气;夏季在C型环流的控制下北京地区降水增多,在SW型环流的控制下北京地区降水偏少,而CSW型环流控制下北京地区呈现干热天气状态,2000年后尤为明显。 相似文献
3.
用NCEP/NCAR再分析资料和华北地区冬季气温资料,运用经验正交分解(EOF)和合成分析等方法,分析了华北地区冬季气温年代际异常及同期环流背景场的变化特征。结果表明:华北冬季气温的年代际变化特征明显;北半球冬季环流场的年代际变化是造成华北冬季气温年代际异常的根本原因,在近地面层,西伯利亚高压偏强时,华北冬季偏冷,反之亦然;在对流层中层,东亚大槽及贝加尔湖高压脊为主要影响系统;低空风场分析结果显示,华北冬季偏冷期中、高纬纬向环流减弱,经向环流明显增强,主要盛行偏北风,暖期情况正好相反。另据分析,北极涛动的年代际变化与华北冬季气温异常也有很好的相关性。 相似文献
4.
影响武汉市空气污染的地面环流形势及其与污染物浓度的关系 总被引：4，自引：4，他引：0
利用Lamb-Jenkinson客观环流分型法,分析2004—2013年影响武汉地区的主要地面环流型及其特点,并探讨环流型与污染物浓度之间的关系。结果表明,影响武汉地区的主要地面环流型有反气旋型(A)、气旋型(C)、偏东风型(E)、高压系统控制的偏东风型(AE)、偏东北风型(NE)及东南风型(SE)。秋、冬季以A、AE、E型为主,春季A、C、E型出现频率最高,夏季则C、E型出现次数最多。空气污染日出现的主要地面环流型有A、AE、E、SE、C及NE型,影响各季节出现污染的主要环流型不同,其中C型主要出现在春、夏季,表现为被弱低压控制;而中度及以上污染日的地面环流型主要为A、SE、E及AE型,受高压系统或偏东风影响时,高浓度污染较易出现。环流型对各种污染物浓度的影响程度存在差异。 相似文献
5.
本研究对比分析了不同气候态下,华北冬、夏季降水及气温的差异,分析了气候平均值的改变对历史极端事件监测的可能影响。研究结果发现,1991～2020年（简称气候Ⅱ态）的冬季和夏季的平均降水量均略多于1981～2010年（简称气候Ⅰ态）,但接近或略少于1961～2020年的平均降水量,平均降水量逐年变化幅度冬季Ⅱ态小于Ⅰ态,夏季反之。气候Ⅱ态冬季降水空间分布不均,夏季较Ⅰ态呈“中部减少,东西增加”的分布型。冬季和夏季极端降水阈值Ⅱ态（0.86 mm和22.0 mm）较Ⅰ态（0.83 mm和21.6 mm）均略有提高,造成近60年华北大部基于Ⅱ态阈值的冬、夏季极端降水日数较Ⅰ态略减少。此外,气候Ⅱ态的华北冬、夏季平均气温均明显高于Ⅰ态,也高于1961～2020年平均值。Ⅱ态气温较Ⅰ态基本呈全区增加特征,但空间分布不均匀。冬季极端低温和夏季极端高温阈值Ⅱ态（-9.8°C和27.9°C）较Ⅰ态（-10.2°C和27.5°C）均有所有所提高,造成华北大部分地区基于Ⅱ态阈值的近60年冬季极端低温日数较Ⅰ态有所增加,夏季极端高温日数较Ⅰ态存在不同程度的减少。因此,新气候态下华北气温和降水均值,华北大部极... 相似文献
6.
中国西部植被覆盖变化对北方夏季气候影响的数值模拟 总被引：6，自引：0，他引：6
植被覆盖的变化是气候变化的成因之一,植被改变对气候的反馈可能会加强或者减缓气候的变化.文中利用CCM3全球气候模式以及20世纪70年代和90年代中国西部的植被覆盖资料进行数值模拟试验,研究了这两个时期植被变化对北方夏季区域气候的影响.模拟结果表明:植被增加的地方,地面吸收的辐射通量增加;植被减少的地方,地面吸收的辐射通量减少.地面辐射平衡的变化造成局地大气热量异常,并引起周边大气热量的调整,从而导致东亚地区夏季大气环流异常.相对于70年代的植被状况,用90年代植被模拟的北方地区对流层上层为异常气旋性环流,而中、低层为异常反气旋环流,东北亚到中国东部盛行异常北风,同时西太平洋副热带高压强度偏弱、位置偏南.这种异常环流特征说明模拟的90年代中国东部夏季风明显减弱,异常的环流形势造成华北和东北地区夏季水汽输送减少,水汽辐合减弱,年降水量减少了40 mm,呈现减少的特征,这是和观测事实是比较吻合的.降水和环流的异常还造成华北和东北夏季平均地面气温降低了0.4-0.8℃.因此近30年来中国西部植被变化可能是东亚夏季风年代际变化以及北方夏季降水减少的一个重要因素. 相似文献
7.
气候变暖背景下我国南方旱涝灾害时空格局变化 总被引：16，自引：7，他引：9
我国南方地区各季节降水异常主要包含三种优势模态：长江及其以南地区降水呈整体偏多或偏少的一致型,长江中下游流域与华南呈反相变化的南北反相型以及东南与西南呈反相变化的东西反相型。其中一致型是南方地区各季节降水变率的第一优势模态。总体而言,在1961—2013年南方地区平均降水存在明显的年代际和长期趋势变化。其中,夏季和冬季南方区域平均降水具有相似的年代际变化特征,而秋季降水的年代际演变几乎与上述两个季节的相反。不过,在近30年南方各季降水量发生年代际转折的时间不尽相同：春季和秋季降水分别在21世纪初期和20世纪80年代中后期之后进入干位相,冬季和夏季降水则分别在80年代中期和90年代初期之后进入湿位相。自21世纪初期以来,南方夏季和冬季降水逐渐转入中性位相。此外,南方春季和秋季降水均呈减少趋势;而夏季和冬季则相反,均呈增多趋势。对于西南地区,除了春季外,其他三个季节的降水均呈减少趋势,出现了季节连旱的特征,尤其是秋旱最为严重。不过,不管是季节降水量还是旱/涝日数,在我国南方大部分地区其线性变化趋势并不十分显著,这与南方降水年代际分量对降水变率存在较大贡献相关。分析还发现,我国南方区域洪涝受灾面积具有比较明显的年代际变化,而干旱受灾面积则没有明显的年代际变化特征,近十多年来西南地区干旱和洪涝受灾出现了交替互现的特点。 相似文献
8.
青藏高原及周围地区大气可降水量的分布、变化与各地多变的降水气候 总被引：56，自引：21，他引：35
为了更深入地分析青藏高原及邻近各地多变的降水气候,利用NCEP 1958—1997年月平均比湿、风及高度等再分析资料及我国实测雨量资料等,整体地分析了高原及周围地区气柱可降水量的多年平均特征及其季节变化,也分析了我国南北方大气可降水量的年代际变化和华北及西北区东部干湿年夏季可降水量的差异等。结果表明,高原及周围地区的气柱可降水量有明显的地区及季节变化。本区域内以南亚和东亚夏季风区的可降水量最高,夏季可达60mm或以上;青藏高原上的可降水量最低,冬季为3mm左右。东亚和南亚季风区可降水量的冬夏季节变化最大,夏季的可降水量达冬季值的4倍。华北区干湿夏季的可降水量差异明显,湿年的可降水量可增加20％以上。近40年来华北和西北区东部夏季的气柱可降水量明显减少,而长江流域及江南地区20世纪80年代以来可降水量却部分增加了,呈北干南湿之势,遂形成我国降水北旱南涝的分布格局。这可能与东亚夏季风逐渐趋弱,特别是撤退期逐渐提前有关。另外,我国各地夏季可降水量的平均降水转化率也明显不同,青藏高原上最高,东亚季风区次之,而南疆盆地最低,这也影响了我国多变的降水气候。 相似文献
9.
近五十年来广西海岛的气候变化与气象灾害特征分析 总被引：1，自引：0，他引：1
《气象研究与应用》2015,(2)
利用涠洲岛气象站自建站至2010年的气象观测资料,分析总结近五十年来广西海岛的气候特征、气候变化规律与气象灾害特征。分析结果表明,随着全球变暖广西海岛的气候发生了明显变化,气温显著升高,特别是90年代后期以来,升温更加显著,冬季对气候变暖的贡献最大;年降水量呈增多趋势,主要来自夏季降水量增多的贡献,从80年代开始降水量增加趋势明显;广西海岛主要的气象灾害发生的频率和强度出现明显变化,台风影响个数略有减少,大风日数呈减少趋势,暴雨、旱涝灾害有所增加,极端天气气候事件造成的灾害损失呈增大趋势。 相似文献
10.
11.
In this study, regional patterns of precipitation in Marmara are described for the first time by means of Ward’s hierarchical cluster analysis. Daily values of winter precipitation data based on 19 meteorological stations were used for the period from 1960 to 2012. Five clusters of coherent zones were determined, namely Black Sea-Marmara, Black Sea, Marmara, Thrace, and Aegean sub-regions. To investigate the prevailing atmospheric circulation types (CTs) that cause precipitation occurrence and intensity in these five different rainfall sub-basins, objective Lamb weather type (LWT) methodology was applied to National Centers of Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis of daily mean sea level pressure (MSLP) data. Precipitation occurrence suggested that wet CTs (i.e. N, NE, NW, and C) offer a high chance of precipitation in all sub-regions. For the eastern (western) part of the region, the high probability of rainfall occurrence is shown under the influence of E (SE, S, SW) atmospheric CTs. In terms of precipitation intensity, N and C CTs had the highest positive gradients in all the sub-basins of the Marmara. In addition, although Marmara and Black Sea sub-regions have the highest daily rainfall potential during NE types, high daily rainfall totals are recorded in all sub-regions except the Black Sea during NW types. 相似文献
12.
Global North Atlantic Oscillation (NAO) oceanic precipitation features in the latter half of the twentieth century are documented based on the intercomparison of multiple state-of-the-art precipitation datasets and the analysis of the NAO atmospheric circulation and SST anomalies. Most prominent precipitation anomalies occur over the ocean in the North Atlantic, where in winter a “quadrupole-like” pattern is found with centers in the western tropical Atlantic, sub-tropical Atlantic, high-latitude eastern Atlantic and over the Labrador Sea. The extent of the sub-tropical and high-latitude center and the amount of explained variance (over 50%) are quite remarkable. However, the tropical Atlantic center is probably the most intriguing feature of this pattern apparently linking the NAO with ITCZ variability. In summer, the pattern is “tripole-like” with centers in the eastern Mediterranean Sea, the North Sea/Baltic Sea and in the sub-polar Atlantic. In the eastern Indian Ocean, the correlation is positive in winter and negative in summer, with some link to ENSO variability. The sensitivity of these patterns to the choice of the NAO index is minor in winter while quite important in summer. Interannual NAO precipitation anomalies have driven similar fresh water variations in these “key” regions. In the sub-tropical and high-latitude Atlantic in winter precipitation anomalies have been roughly 15 and 10% of climatology per unit change of the NAO, respectively. Decadal changes of the NAO during the last 50 years have also influenced precipitation and fresh water flux at these time-scales, with values lower (higher) than usual in the high-latitude eastern North Atlantic (Labrador Sea) in the 1960s and the late 1970s, and an opposite situation since the early 1980s; in summer the North Sea/Baltic region has been drier than usual during the period 1965–1975 when the NAO was generally positive. 相似文献
13.
我国四季极端雨日数时空变化及其与海表温度异常的关系 总被引：3，自引：0，他引：3
利用1960—2004年我国586个气象站的逐日降水观测资料,对每个季节和每个站点,以雨日降水量升序排列的第90个百分位值定义极端日降水阈值,分析揭示了我国四季极端雨日数的时空变化特征、与海表温度异常的关系以及相联系的大气环流异常型。结果表明,我国长江流域极端雨日数在冬季和夏季呈显著增加趋势,华北地区极端雨日数在冬季显著增加、而在夏季显著减少,华南地区极端雨日数在春季显著增加,东北地区极端雨日数在冬季和春季显著增加,而西北地区极端雨日数在四季均显著增加。各季极端雨日数在线性趋势变化之上表现年际和年代际变化特征,并且其典型异常型明显不同,春、秋季表现为长江以南与以北地区反位相的"偶极型"变化,夏季表现为长江流域与华南、华北地区反位相的"三极型"变化,冬季表现为全国大部分地区同位相的"单极型"变化。我国季节极端雨日数与印度洋-太平洋海表温度异常的关系主要表现为与ENSO的关系,而ENSO影响我国极端降水异常是通过相应的大气环流异常型来实现的。 相似文献
14.
Changes in atmospheric circulation over Europe detected by objective and subjective methods 总被引：1，自引：0，他引：1
Summary Changes in atmospheric circulation over Europe since 1958 were examined using both objective (modes of low-frequency variability
and objective classification of circulation types) and subjective (Hess-Brezowsky classification of weather types) methods.
The analysis was performed with an emphasis on the differences between the winter (DJF) and summer (JJA) seasons, and between
objectively and subjectively based results. Majority of the most important changes in atmospheric circulation are same or
similar for the objective and subjective methods: they include the strengthening of the zonal flow in winter since the 1960s
to the early 1990s; the increase (decrease) in frequency of anticyclonic (cyclonic) types in winter from the late 1960s to
the early 1990s, with a subsequent decline (rise); and the sharp increase in the persistence (measured by the mean residence
time) of all groups of circulation types in winter around 1990 and of anticyclonic types in summer during the 1990s. Differences
between the findings obtained using the objective and subjective methods may result from the intrinsically different approach
to the classification (e.g. the Hess-Brezowsky weather types have a typical duration of at least 3 days while objective types
typically last 1–3 days). Generally, changes in atmospheric circulation which have taken place since the 1960s were more pronounced
in winter than in summer. The most conspicuous change seems to be the considerable increase in the persistence of circulation
types during the 1990s, which may be also reflected in the increase in the occurrence of climatic extremes observed in Europe
during recent years. 相似文献
15.
LIU Yu HE Jinhai LI Weiliang CHEN Longxun LI Wei ZHANG Bo 《Acta Meteorologica Sinica》2010,24(4):468-483
Using a regional climate model MM5 nested with an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate responses of the mid-Holocene climate to different factors over China. Model simulations of the mid-Holocene climate change, especially the precipitation change, are in good agreement with the geologic records. Model results show that relative to the present day (PD) climate, the temperature over China increased in the mid-Holocene, and the increase in summer is more than that in winter. The summer monsoon strengthened over the eastern China north of 30°N, and the winter monsoon weakened over the whole eastern China; the precipitation increased over the west part of China, North China, and Northeast China, and decreased over the south part of China.The sensitive experiments indicate that changes in the global climate (large-scale circulation background),vegetation, earth orbital parameter, and CO2 concentration led to the mid-Holocene climate change relative
to the PD climate, and changes in precipitation, temperature and wind fields were mainly affected by change of the large-scale circulation background, especially with its effect on precipitation exceeding 50%. Changes in vegetation resulted in increasing of temperature in both winter and summer over China, especially over eastern China; furthermore, its effect on precipitation in North China accounts for 25% of the total change.Change in the orbital parameter produced the larger seasonal variation of solar radiation in the mid-Holocene than the PD, which resulted in declining of temperature in winter and increasing in summer; and also had
an important effect on precipitation with an effect equivalent to vegetation in Northeast China and North China. During the mid-Holocene, CO2 content was only 280×10-6, which reduced temperature in a very small magnitude. Therefore, factors affecting the mid-Holocene climate change over China from strong to weak are large-scale circulation pattern, vegetation, earth orbital parameter, and CO2 concentration. 相似文献
16.
Extreme midlatitude cyclone characteristics, precipitation, wind speed events, their inter-relationships, and the connection
to large-scale atmospheric patterns are investigated in simulations of a prolonged cold period, known as the Maunder Minimum
from 1640 to 1715 and compared with today. An ensemble of six simulations for the Maunder Minimum as well as a control simulation
for perpetual 1990 conditions are carried out with a coupled atmosphere-ocean general circulation model, i.e., the Climate
Community System Model (CCSM). The comparison of the simulations shows that in a climate state colder than today the occurrence
of cyclones, the extreme events of precipitation and wind speed shift southward in all seasons in the North Atlantic and the
North Pacific. The extremes of cyclone intensity increases significantly in winter in almost all regions, which is related
to a stronger meridional temperature gradient and an increase in lower tropospheric baroclinicity. Extremes of cyclone intensity
in subregions of the North Atlantic are related to extremes in precipitation and in wind speed during winter. Moreover, extremes
of cyclone intensity are also connected to distinct large-scale atmospheric patterns for the different subregions, but these
relationships vanish during summer. Analyzing the mean 1,000 hPa geopotential height change of the Maunder Minimum simulations
compared with the control simulation, we find a similar pattern as the correlation pattern with the cyclone intensity index
of the southern Europe cyclones. This illustrates that changes in the atmospheric high-frequency, i.e., the simulated southward
shift of cyclones in the North Atlantic and the related increase of extreme precipitation and wind speed in particular in
the Mediterranean in winter, are associated with large-scale atmospheric circulation changes. 相似文献
17.
Predominantly in the context of Japan GMS-derived T_(BB) data,study is undertaken of therelationship between the winter thermal conditions of the Qinghai-Xizang Plateau(QXP)andanomaly in Asian-Australian monsoons during northern summer.Evidence suggests that anti-correlation of cold air activity of East Asia with that of Mid Asia is responsible for the counterpartof the ground thermal characteristics anomaly on an interannual basis between the SW and NEQXP;the winter thermal pattern bears a closer correlativity with the subsequent summertimeAsian-Australian monsoons anomaly;as the thermal distribution is reversed,so are the convectionfeatures over North and South China,maritime continent,the NW and SW Pacific at tropical andequatorial latitudes,resulting in vast difference between East-Asian summer and Indonesian-NorthAustralian winter monsoons;the subtropical monsoon-associated rainbelt over the mid-lowerChangjiang basins exhibits the discrepancy in vigor and northerly shift timing.Besides,part of theresults has been further borne out through analysis of temperature and precipitation records of theeastern portion of the country in monsoon climate. 相似文献
18.
A 10-yr regional climate simulation was performed using the fifth-generation PSU/NCAR Mesoscale Model Version 3 (MM5V3) driven by large-scale NCEP/NCAR reanalyses. Simulations of winter and summer mean regional climate features were examined against observations. The results showed that the model could well simulate the 10-yr winter and summer mean circulation, temperature, and moisture transport at middle and low levels. The simulated winter and summer mean sea level pressure agreed with the NCAR/NCEP reanalysis data. The model could well simulate the distribution and intensity of winter mean precipitation rates as well as the distribution of summer mean precipitation rates, but it overestimated the summer mean precipitation over North China. The model's ability to simulate the regional climate change in winter was superior to that in summer. In addition, the model could simulate the inter-annual variation of seasonal precipitation and surface air temperature. Geopotential heights and temperature at middle and high levels between simulations and observations exhibited high anomaly correlation coefficients. The model also showed large variability to simulate the regional climate change associated with the El Nino events. The MM5V3 well simulated the anomalies of summer mean precipitation in 1992 and 1995, while it demonstrated much less ability to simulate that in 1998. Generally speaking, the MM5V3 is capable of simulating the regional climate change, and could be used for long-term regional climate simulation. 相似文献
19.
东亚区域气候变化的长期数值模拟试验 总被引：16，自引：4，他引：16
文中利用NCAR的中尺度模式MM 5V3对东亚地区进行了 10a的长期积分模拟试验 ,并着重对冬、夏两季东亚区域气候变化特征进行了分析。分析结果表明 :(1)模式能够合理地模拟出 10a冬、夏平均的区域气候特征。模拟的 10a冬季平均降水的分布和强度与实际比较一致 ,对夏季降水分布特征的模拟也比较合理 ,但模拟的夏季华北降水偏多。模式对冬季平均场的模拟要优于对夏季的模拟 ;(2 )模式对降水、地面气温年际变率的模拟较为合理 ,模拟的中高层环流、温度场等要素的距平相关系数都比较高 ;(3)模式对不同ElNi no年对东亚区域气候变化影响的模拟能力有所不同 ,模拟的 1992 ,1995年的结果比较合理 ,但对 1998年模拟得不理想 ;(4)MM5V3模式具备一定的区域气候模拟能力。 相似文献