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1.
NCEP/NCAR和ERA-40再分析资料以及探空观测资料分析中国北方地区年代际气候变化 总被引：33，自引：7，他引：26
利用中国东部的探空站资料以及ERA40和NCAR/NCEP再分析资料,详细地比较了我国北方地区(主要指内蒙古以及华北地区)的高低层位势高度以及温度的特征.结果表明,在20世纪70年代以前,NCEP/NCAR再分析资料对我国北方地区对流层低层无论是位势高度或温度都描述不好,存在着很明显的虚假年代际变化趋势.与实际探空资料相比,相对于NCEP/NCAR再分析资料,ERA-40再分析资料对东亚地区对流层低层位势高度或温度的描述明显好于NCEP/NCAR再分析资料,因此,研究东亚气候的年代际变化应用ERA-40再分析资料要好一些.高层的结果要比低层好.在70年代以后,NCEP/NCAR再分析资料对于内蒙古和华北对流层上层的位势高度和温度的描述要好于ERA-40再分析资料,更接近于实际探空值,这说明这两份再分析资料各有优缺点.
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2.
比较NCEP/NCAR和ERA-40再分析资料与观测资料计算得到的感热资料的差异 总被引：9，自引：2，他引：7
利用1951～2000年我国西北干旱、半干旱区地温、气温和表面风场逐日4个时次（北京时间2、8、14和20时）的台站观测资料,以及NCEP/NCAR和ERA-40再分析资料,计算并比较了在我国西北地区春夏季感热输送的差异。分析结果表明:NCEP/NCAR和ERA-40的感热输送再分析资料都能显示出我国西北地区是欧亚大陆上的感热中心之一。从年代际时间尺度上,ERA-40再分析资料的感热资料更接近于实际台站观测资料计算得到的感热资料。
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3.
应用探空观测资料评估几类再分析资料在中国区域的适用性 总被引：14，自引：4，他引：10
通过与中国8个不同区域温度场和高度场的探空观测资料相比较发现, ERA-40、NCEP/NCAR和NCEP/DOE等再分析资料所描述的温度场和高度场产品的平均值以及年际变化特征等与观测结果的差异均在夏季比较明显, 尤其1970年代以前在中国的西部和西南部地区的差别较为显著。其中, 温度场的差别主要存在于对流层上层; 高度场的绝对偏差也主要出现在对流层上层, 而它们在年际变化特征及其长期变化趋势上的差别则反映在对流层中、下层, 特别是NCEP/NCAR对流层中、下层的夏季高度场在1970年代以前存在着过于明显的“低压” 现象, 从而夸大了很多地区的年代际气候变化特征。就大多数地区而言, ERA-40在中国区域气候变化研究中具有相对较好的适用性, 特别是在年代际气候变化研究中要明显好于NCEP/NCAR。研究还表明, NCEP/DOE与NCEP/NCAR在大多数地区除了在均值上有所不同外, 它们的年际变化特征则并无显著差别。 相似文献
4.
应用台站观测资料对ERA-40, NCEP/NCAR以及NCEP/DOE再分析地表气压产品在中国不同区域、不同年代和不同季节的适用性进行了评估。分析发现, 几种再分析产品虽然能在一定程度上反映出观测资料所具有的时空分布特征, 但它们之间的差异却具有明显的区域和季节变化特征, 即冬季小而夏季大、东部地区小而西部地区大; 同时还发现ERA-40和NCEP/NCAR再分析产品在20世纪70年代以前均与观测资料有相对较大的差别, 特别是NCEP/NCAR在70年代以前的夏季气压值过于偏低, 从而夸大了很多地区的年代际变化特征。相比而言, ERA-40地表气压的长期变化趋势以及时空演变规律在中国大多数地区要优于NCEP/NCAR再分析产品, 特别是在中国西部地区。分析还表明, NCEP/DOE虽与观测资料存在一定的系统性偏差, 却与另外两种再分析产品有着较为相似的年际变化特征及趋势。 相似文献
5.
应用台站观测资料对ERA-40、NCEP/NCAR、NCEP/DOE和JRA-25等几种再分析地表(2m)气温资料在中国不同区域、不同年代和季节的气候均值、年际变化和变率特征及其气候趋势等所反映出来的适用性问题进行了系统评估.结果表明,几种再分析产品在全国大多数地区的气候变化研究中都具有一定的合理性,特别是1979年以后的资料可靠性更高一些.但相比而言,它们在冬季的可信度一般要高于夏季,东部地区的可信度一般要高于西部地区;ERA-40和JRA-25再分析产品的适用性要高于NCEP/NCAR和NCEP/DOE再分析产品;其中,JRA-25在均值、年际变化和变率特征的描述上具有更高的可靠性,而ERA-40在长期气候变化趋势(44年)的描述上则要明显优于NCEP/NCAR再分析产品. 相似文献
6.
利用1971—2001年探空资料以及ERA-40和NCEP/NCAR再分析资料分别得到地面到300 hPa我国大陆上空大气柱水汽含量,对3种不同资料所得的柱水汽含量的空间分布特征以及线性趋势进行对比分析。结果表明:3种资料得到的柱水汽含量年平均和季节平均的空间分布特征一致;3种资料年平均的线性变化趋势在东北地区、内蒙古东部地区,西南地区北部、华南沿海和新疆北部地区均呈增加趋势;在华北和华东的部分地区,ERA-40和NCEP/NCAR再分析资料为降低趋势,而探空资料得到的柱水汽含量变化相对较小,但未通过信度检验;探空资料得到的柱水汽含量的相对变化显示我国东北地区、内蒙古东部地区、新疆地区的增加更显著。 相似文献
7.
两种再分析资料平流层温度场的对比分析 总被引：4，自引：0，他引：4
在Lorenz环流分解基础上,比较了全球平流层低层ECMWF和NCEP/NCAR两种再分析资料月平均温度场的差异。结果表明：（1）纬向的平均温度无论DJF季度还是JJA季度100 hPa,30°S～30°N纬带都是冷中心;在该冷纬带ECMWF资料温度均值显著低于NCEP资料,ECWMF资料的年际方差显著小于NCEP资料。（2）30 hPa以上NCEP资料的定常波比较杂乱,在中纬大陆上出现与事实不符的高低中心,而ECMWF资料反映的气温定常波则比较合理。（3）ECMWF资料在100 hPa和10 hPa上气温异常未能充分地反映近50 a来3次强的火山喷发引起的平流层增温。 相似文献
8.
9.
夏季NCEP资料质量和20世纪70年代东亚热低压的突变 总被引：16，自引：5，他引：16
应用NCEP-NCAR再分析资料,分析了1958—2002年夏季北半球1000 hPa和500 hPa位势高度场的年际变化。发现整个北半球位势高度场都出现大范围的升高趋势,升高中心主要位于35°~55°N,90°~115°E范围内,即夏季东亚热低压区域;定义该范围内位势高度场的平均值为夏季东亚热低压指数(简写为SEAL)。在1958—1968年间SEAL值有非常明显的升高,数值达60 gpm以上。应用欧洲中心的ERA-40再分析资料和中国气象局的500 hPa位势高度场资料,计算同样范围的SEAL指数,并与NCEP-NCAR资料进行对比,结果表明,在1958—1968年间NCEP-NCAR资料的值远小于上述两份资料,相关计算结果是NCEP资料与两份资料无关。而在1968年以后,上述3份资料的时间序列却是十分相似,相关值都通过信度检验,表现为1968—1976年都有增大的趋势。1977年以后,3份资料的SEAL指数都趋向平缓,即在1970年代中后期北半球东亚夏季环流有一明显的突变。环流突变主要发生在东亚热低压区,在北半球中低纬度的大范围区域对流层中低层都有反映;但在中高纬度地区,相对而言,气候突变是不显著的。大范围的环流变化影响东亚夏季风的位置和强度,也影响我国的降水量和降水分布。 相似文献
10.
利用NCEP/NCAR, NCEP/DOE和ERA40 3套再分析资料的逐日200 hPa纬向风数据,选取1961—1990年、1971—2000年和1981—2010年3种不同气候态,对比分析了3种气候态下热带大气季节内振荡 (ISO) 的基本气候特征及其在不同再分析资料中的异同。研究表明:1981—2010年气候态下,热带大气ISO冬春强、夏秋弱的年循环特征更加明显,东传短波能量增强,起始北传时间偏晚。NCEP/NCAR与NCEP/DOE资料所表征的热带大气ISO在空间分布、强度和能量传播方面的一致性较好。NCEP/NCAR资料反映的热带大气ISO强度在热带印度洋和热带西太平洋地区较ERA40资料偏弱,在赤道东太平洋地区较ERA40资料偏强;ERA40资料反映的热带大气ISO强度在12月—次年3月中旬较NCEP/NCAR资料偏强,而在3月中旬—11月偏弱;ERA40资料反映的热带大气ISO振荡位相较NCEP/NCAR资料超前10 d左右;NCEP/NCAR资料反映的东传谱能量弱于ERA40资料,西传能量强于ERA40资料;7月中旬,NCEP/NCAR资料反映的东亚地区大气ISO经向北传较ERA40资料偏晚。 相似文献
11.
An intercomparison of summertime (JJA)subtropical geopotential heights from the ERA-40 and NCEP/NCAR reanalysis is specifically conducted over East Eurasia and the western North Pacific. The NCEP/NCAR is obviously lower than the ERA-40 in the mid-to-lower troposphere in most regions of East Eurasia before the mid-1970s, but becomes higher than the ERA-40 after the mid-1970s and thus demonstrates stronger increased trends during the period of 1958-2001. Both reanalyses are lower than the observations in most regions of China. The NCEP/NCAR especially shows tremendously systematic lower values before the mid-1960s and displays abrupt changes before the 1970s. Several indices of the western North Pacific subtropical high (WNPSH), calculated from both reanalyzed summer geopotential heights, also reveal that the variation trend of the NCEP/NCAR is stronger than that of the ERA-40 in the mid-to-lower troposphere from 1958 to 2001. Through singular value decomposition (SVD) analysis, the summer geopotential heights at 500 hPa from the ERA-40 are better than the NCEP/NCAR counterparts at interacting with the precipitation over the East Asian monsoon region. The results indicate that the NCEP/NCAR in the mid-and-lower troposphere may overestimate interdecadal changes and should be used cautiously to study the relationship between the WNPSH and precipitation ove ther East Asia Monsoon region before the mid-1970s. 相似文献
12.
Intercomparison of the Summertime Subtropical High
from the ERA-40 and NCEP/NCAR Reanalysis over
East Eurasia and the western North Pacific 总被引：2，自引：1，他引：1
An intercomparison of summertime (JJA) subtropical geopotential heights from the ERA-40 and NCEP/NCAR
reanalysis is specifically conducted over East Eurasia and the western North Pacific. The NCEP/NCAR is obviously
lower than the ERA-40 in the mid-to-lower troposphere in most regions of East Eurasia before the mid-1970s, but
becomes higher than the ERA-40 after the mid-1970s and thus demonstrates stronger increased trends during the
period of 1958--2001. Both reanalyses are lower than the observations in most regions of China. The NCEP/NCAR
especially shows tremendously systematic lower values before the mid-1960s and displays abrupt changes before
the 1970s. Several indices of the western North Pacific subtropical high (WNPSH), calculated from both reanalyzed
summer geopotential heights, also reveal that the variation trend of the NCEP/NCAR is stronger than that of the
ERA-40 in the mid-to-lower troposphere from 1958 to 2001. Through singular value decomposition (SVD) analysis,
the summer geopotential heights at 500 hPa from the ERA-40 are better than the NCEP/NCAR counterparts at
interacting with the precipitation over the East Asian monsoon region. The results indicate that the NCEP/NCAR
in the mid-and-lower troposphere may overestimate interdecadal changes and should be used cautiously to study
the relationship between the WNPSH and precipitation ove ther East Asia Monsoon region before the mid-1970s. 相似文献
13.
Climatology and interannual variability of storm-tracks in the Euro-Atlantic sector: a comparison between ERA-40 and NCEP/NCAR reanalyses 总被引：2，自引：0，他引：2
Isabel Franco Trigo 《Climate Dynamics》2006,26(2-3):127-143
An objective methodology is applied to ERA-40 (European Centre for Medium-Range Weather Forecasts 40-year Reanalysis) and
NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalyses, to build two
storm-track databases for the Euro-Atlantic sector (85°W–70°E; 20°N–75°N), spanning the period December 1958–March 2000. The
technique uses the full temporal (6-hourly) and spatial resolutions (1.125° and 2.5° regular grids, for ERA-40 and NCEP/NCAR,
respectively) available. It is shown that the strong discrepancies in the number of storms in each dataset (higher for ERA-40)
result from differences in the resolution of the fields subject to the storm detecting/tracking algorithm, and also from the
characteristics of the integration models and assimilation schemes used for each reanalysis. An intercomparison of ERA-40
and NCEP/NCAR storm-tracks is performed for spatial distribution, and main characteristics, of the overall cyclone population
and of a class of severe storms—explosive cyclones. Despite the discrepancies in storm numbers, both reanalyses agree on the
main cyclone activity areas (formation, minimum central pressure, and lysis). The most pronounced differences occur where
subsynoptic systems are frequent, as these are better resolved by ERA-40 data. The interannual variability of cyclone counts,
analysed per intensity classes and for different regions of the domain, reveals reasonable agreement between the two datasets
on the sign of trends (generally positive in northern latitudes, and negative in the Azores-Mediterranean band), but discrepancies
regarding their strength in the most southern areas, where the mismatches between ERA-40 and NCEP/NCAR detected lows are greatest.
Submitted to Climate Dynamics in December 2004 相似文献
14.
Intercomparison of the South Asian High in NCEP1, NCEP2, and ERA-40 Reanalyses and in Station Observations 
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下载免费PDF全文 The South Asian Highs (SAHs) at 100 hPa over China in the three reanalysis datasets NCEP1, NCEP2, and ERA-40 are evaluated by using station observation data. The results demonstrate a substantial discrepancy even between the reanalyses. First, the data of the three reanalyses generally underestimate the intensity of the SAH in the China domain. Second, there are interdecadal changes in the SAH, with highs in the 1960s and 1980s and lows in the 1970s, 1990s, and 2000s. This interdecadal variation of the SAH can be well depicted with NCEP1 data, but the high in the 1980s is missed by ERA-40. The NCEP2 corresponds well with NCEP 1 and captures the decreasing trend after 1979. Furthermore, the NCEP1 reanalysis overestimates the interdecadal changes of SAH, while ERA-40 underestimates the interdecadal changes. This work suggests that much caution should be exerted when the reanalysis datasets are adopted to study the interdecadal variability of SAH. 相似文献
15.
A new empirical approach for the seasonal prediction of annual Atlantic tropical storm number (ATSN) was developed using precipitation and 500 hPa geopotential height data from the preceding January-February and April-May. The 2.5º×2.5º resolution reanalysis data from both the US National Center for Environmental Prediction/the National Center for Atmospheric Research (NCEP/NCAR) and the European Center for Medium-Range Weather Forecasting (ECMWF) were applied. The model was cross-validated using data from 1979-2002. The ATSN predictions from the two reanalysis models were correlated with the observations with the anomaly correlation coefficients (ACC) of 0.79 (NCEP/NCAR) and 0.78 (ECMWF) and the multi-year mean absolute prediction errors (MAE) of 1.85 and 1.76, respectively. When the predictions of the two models were averaged, the ACC increased to 0.90 and the MAE decreased to 1.18, an exceptionally high score. Therefore, this new empirical approach has the potential to improve the operational prediction of the annual tropical Atlantic storm frequency. 相似文献