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应用Lamb-Jenkinson大气环流分型方法对横断山脉地区的8个经度×10个纬度范围内1948-2012年逐日平均的海平面气压场进行环流分型,由日平均海平面气压场算出6个环流指数（u、v、V、ξu、ξv、ξ）,并由此划分出27种不同的环流型。分型结果表明：横断山脉地区主要环流分型为E型、NE型、SE型、N型和C型,其频率分别为：21.4%、14.6%、13.7%、9.8%和9.5%;E和NE型环流频率逐渐增加,C型环流型频率逐渐减少。春季横断山脉地区主导环流比较繁琐;NE、N型为夏季的主要环流型,但E型环流在夏季的频率也相当大;秋季和冬季横断山脉地区的主导环流型都为E型和SE型。夏季主导环流型持续时间较长,冬季也是主导环流持续的时间较长,个别年份主导环流型持续时间超过了一个月,这主要与横断山脉地区复杂的地形有联系。 相似文献
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应用Lamb-Jenkinson大气环流分型法对渤海海峡1979—2013年逐日海平面气压场进行大气环流客观分型,分析了渤海海峡大风天气与大气环流型的关系;以长岛气象站在渤海海峡大风天气中的指示作用为基础,分析了主要环流型下大风天气的气候特征。结果表明：渤海海峡大风天气以平直环流型为主,偏北型明显多于偏南型;春（夏）季是发生大风天气最多（少）的季节,以西南（SW）型出现频率最高,秋、冬季大风天气的环流型频率分布基本相同,均以偏北型为主;不同环流型下出现大风天气的概率及大风天气的气候特征也有明显不同。 相似文献
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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
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利用Lamb-Jenkinson大气环流分型方法,对西江流域1971—2015年逐日平均850 hPa和500 hPa高度场进行环流客观分型,分析流域降水天气环流型出现概率及主导环流型变化特征,探讨主导环流型对西江流域总面雨量和子流域面雨量的贡献率及环流型配置与降水的关系。结果表明:当850 hPa为西南风型、500 hPa为西风型时,流域出现降水天气的概率最大;850 hPa气旋型和500 hPa西风型对年总面雨量和各子流域面雨量的贡献率均为最大,且对东部子流域面雨量的贡献率大于西部子流域,850 hPa南风型与500 hPa反气旋型的环流配置是西部子流域秋季降水偏多的主导环流型配置;春季850 hPa气旋型与500 hPa西风型、夏季850 hPa气旋型与500 hPa西风型、秋季850 hPa南风型与500 hPa反气旋型、冬季850 hPa西南风型与500 hPa西风型的环流配置时,出现强降水天气的概率分别为18.7%,21.1%,4.0%和2.0%,即夏季最大,其次为春季,冬季最小。近45年,850 hPa气旋型、500 hPa西风型对流域年总面雨量的贡献率呈增加趋势,是西江流域面雨量呈偏多趋势的主导环流型。 相似文献
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Lamb-Jenkinson环流客观分型方法及其在中国的应用 总被引：3，自引：0，他引：3
介绍了Lamb-Jenkinson客观环流分型方法.利用1948年1月1日-2004年12月31日的NCEP逐日平均海平面气压资料,计算了中国16个区逐日的6个环流指数及相应的环流分类,分析了中国各区域不同季节各种环流类型出现的频率及其变化特征.结果表明,该方法在我国大部分地区适用,虽然在西部高海拔地区的海平面气压可能有订正误差,但该方法是可行的.对1958-2004年以来3个主要环流指数的线性趋势分析显示,华北及河套至内蒙古中西部地区夏季的经向风指数和纬向风指数下降明显,涡度指数也有明显的下降,表明控制上述地区的高值系统有增多趋势,而准地转西南风减弱,这可能是造成这些地区干旱化的重要环流背景.对冬季而言,我国东北、华北和新疆北部等地区的纬向风指数上升明显,表明我国北部地区冬季的近地层西风有加强的趋势,这与近年来这些地区冬季气温显著升高有密切关系. 相似文献
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The Influence of Large-Scale Circulation on the Summer Hydrological Cycle in the Haihe River Basin of China 
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下载免费PDF全文 OU Tinghai LIU Yanxiang CHEN Deliang David RAYNER ZHANG Qiang GAO Ge XIANG Weiguo 《Acta Meteorologica Sinica》2011,25(4):517-526
In this study, we focus on changes in three important components of the hydrological-cycle in the Haihe River basin (HRB) during 1957-2005: precipitation (Prep), actual evaportranspiration (ETa), and pan evaporation (PE)-a measure of potential evaporation. The changes in these components have been evaluated in relation to changes in the East Asian summer monsoon. Summer Prep for the whole basin has decreased significantly during 1957-2005. Recent weakening of the convergence of the integrated water vapor flux, in combination with a change from cyclonic-like large-scale circulation conditions to anti-cyclonic-like conditions, led to the decrease in the summer Prep in the HRB. ETa is positively correlated with Prep on the interannual timescale. On longer timescales, however, ETa is less dependent on Prep or the large-scale circulation. We found negative trends in ETa when the ERA40 reanalysis data were used, but positive trends in ETa when the NCEP/NCAR reanalysis data were used. PE declined during the period 1957-2001. The declining of PE could be explained by a combination of declining solar radiation and declining surface wind. However, the declining solar radiation may itself be related to the weakening winds, due to weaker dispersion of pollution. If so, the downward trend of PE may be mainly caused by weakening winds. 相似文献
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In this study,we focus on changes in three important components of the hydrological-cycle in the Haihe River basin (HRB) during 1957-2005:precipitation (Prep),actual evaportranspiration (ETa),and pan evaporation (PE)- a measure of potential evaporation.The changes in these components have been evaluated in relation to changes in the East Asian summer monsoon.Summer Prep for the whole basin has decreased significantly during 1957-2005.Recent weakening of the convergence of the integrated water vapor flux,in combination with a change from cyclonic-like large-scale circulation conditions to anti-cyclonic-like conditions,led to the decrease in the summer Prep in the HRB.ETa is positively correlated with Prep on the interannual timescalc.On longer timescales,however,ETa is less dependent on Prep or the large-scale circulation.We found negative trends in ETa when the ERA40 reanalysis data were used,but positive trends in ETa when the NCEP/NCAR reanalysis data were used.PE declined during the period 1957 2001.The declining of PE could be explained by a combination of declining solar radiation and declining surface wind.Howevcr,the declining solar radiation may itself be related to the weakening winds,due to weaker dispersion of pollution.If so,the downward trend of PE may be mainly caused by weakening winds. 相似文献
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