共查询到18条相似文献，搜索用时 125 毫秒
1.
使用Emanuel和Nolan完善的潜在生成指数(GPI)的计算方法,利用美国联合台风警报中心提供的热带气旋(TC)资料和欧洲中期数值天气预报中心提供的全球ERA-40再分析资料,比较了1970-2001年西北太平洋海域的TC生成频数和GPI的气候特征,分析了包含于GPI中的环境要素对西北太平洋TC频数年代际变化空间分布的影响.结果表明:GPI能近似地表述西北太平洋TC频数的季节变化和空间分布.各环境要素对TC、较弱类TC和较强类TC生成频数的影响有显著差异,相对湿度随着TC强度的增强而减弱,风速垂直切变则相反.西北太平洋TC频数年代际变化空间分布的正异常主要分布于130°E以东,(15°N,140°E)附近最大的正异常频数中心主要受绝对涡度和相对湿度正异常变化的影响;负的风速垂直切变和正的相对湿度异常变化引起了(10～15°N,160°E)附近的TC频数正异常. 相似文献
2.
现阶段使用的热带气旋潜在生成指数(Genesis Potential Index,GPI)在气候场的空间分布上能很好地拟合热带气旋的生成情况,但在热带气旋的年际变化拟合上效果很差。本研究考虑了相对涡度在热带气旋年际变化拟合上的重要作用,并以此为出发点,尝试改善GPI在西北太平洋地区的拟合效果。基于对1979—2011年美国联合飓风警报中心提供的热带气旋最佳路径数据和NCEP/NCAR再分析资料数据集的研究,将之前GPI中的绝对涡度项替换为修正过的相对涡度项。科氏力项仍然保留;将南海(100°～120°E,5°～25°N)与西北太平洋地区(120°～180°E,5°～40°N)热带气旋生成的差异性也纳入了考量,并在这两个区域分别构建GPI公式,改善了对热带气旋生成的气候分布模拟。除此之外,较之已存的GPI指数,改进后的GPI还很大程度提高了GPI对热带气旋生成年际变化的拟合效果,特别是对弱热带气旋年际变化的拟合效果有了显著提升。 相似文献
3.
本文利用ERA5 1979-2019年逐月大气再分析资料计算南北印度洋热带气旋生成指数，并和IBTrACS观测数据进行比较，探讨用热带气旋生成指数研究南北印度洋热带气旋变化特征的适用性.研究发现热带气旋生成指数能较好地刻画南北印度洋热带气旋的空间分布特征、北印度洋热带气旋个数月变化的双峰结构，以及南印度洋比北印度洋热带气旋发生概率高等特征.最新的IBTrACS v4.0观测资料显示，40年来北印度洋热带气旋每年总生成个数平均每10年增加1.3个，频数的增加主要来源于热带低压和热带风暴，而南印度洋热带气旋每年总生成个数每10年减少2.8个.热带气旋生成指数能很好地描述北印度洋热带气旋生成个数的上升趋势，但对南印度洋热带气旋生成个数趋势的刻画与观测不一致，可能原因需要进一步深入研究. 相似文献
4.
本研究评估了现有热带气旋(Tropical Cyclone,TC)潜在生成指数(Genesis Potential Indice,GPI)对北大西洋和西北太平洋热带气旋生成频数(TC Genesis Frequency,TCGF)时空特征的表征能力。结果表明,现阶段使用的GPIs能较好地再现两个海盆TCGF的空间分布和季节循环特征,以及北大西洋TCGF的年际变化,但几乎不能模拟西太平洋TCGF年际时间尺度上的变化。利用美国联合飓风警报中心(Joint Typhoon Warming Center,JTWC)提供的1979—2017年热带气旋最佳路径数据集和ERA-Interim再分析数据,对西北太平洋GPI进行了改进。考虑到相对涡度在西北太平洋对热带气旋生成的重要作用,将绝对涡度分离为相对涡度和地转涡度(f),移除相对湿度,使用多元线性回归的方法构建了GPIWNP。与现有GPIs相比,改进后的GPIWNP不仅对西北太平洋TCGF的空间分布和季节循环有较好的模拟能力,并且可以再现其年际变化特征。 相似文献
5.
西北太平洋热带气旋潜在生成指数的改进 总被引：7，自引：2，他引：5
热带气旋潜在生成指数(GPI,Genesis Potential Index)是热带气旋生成可能性大小的空间分布函数,利用大尺度环境场可以应用于热带气旋活动的季节预报,并且可以评估全球气候变化对热带气旋活动的影响。但是目前的GPI基本都是针对全球热带气旋活动构建的,没有考虑到热带气旋不同活动地区及其内部的差异。本研究考虑到南海和西北太平洋热带气旋生成的不同特点,分别构建了适用于南海(5～25°N,100～120°E)和西北太平洋(5～40°N,120～180°E)的热带气旋GPI。改进后的GPI对南海和西北太平洋区域热带气旋生成具有较好的模拟能力,不仅能很好地模拟南海和西北太平洋热带气旋生成频数空间分布的气候特征(相似系数为0.67),而且能够较好地模拟热带气旋生成在年际时间尺度上的空间分布特征。 相似文献
6.
利用美国联合台风警报中心(Joint Typhoon Warning Centre,JTWC)发布的1979—2018年北印度洋热带气旋(tropical cyclone,TC)数据和ERA-Interim提供的分辨率为1°×1°的同期再分析资料,分析影响北印度洋热带气旋生成的不同环境因子月际变化特征。结果表明:5月北印度洋海温明显增暖,适宜的200 hPa与850 hPa垂直风速切变(5~10 m·s^(-1))和充足的水汽供应使得热带气旋的生成数达到全年第一个峰值。7—9月对流层中低层相对湿度条件很好,但200 hPa与850 hPa垂直风速切变过大,使得扰动对流很难形成暖心结构,不利于热带气旋的生成。10—11月北印度洋平均海温27~29℃,中层大气相对湿度条件较好,850 hPa多气旋性环流,200 hPa与850 hPa垂直风速切变为5~15 m·s^(-1),在这种有利的环境条件下北印度洋热带气旋生成数达到全年第二个峰值。对影响北印度洋两个海域热带气旋月际变化的不同环境因子定量研究发现,尽管阿拉伯海和孟加拉湾的热带气旋生成数都呈现双峰型变化,但环境因子在相同月份却呈现不一样的特征。 相似文献
7.
利用江苏省2010—2015年的60个站点土壤湿度观测资料,对欧洲中心ERA-Interim再分析资料(ERA)和美国宇航局再分析资料(MERRA)的两套土壤湿度数据在江苏地区的可靠性进行了评估。结果表明:相比于ERA再分析资料,MERRA较好地再现出江苏省次表层年平均土壤湿度的空间分布特征,但是两种资料的次表层和深层土壤湿度的数值均小于观测。ERA和MERRA基本都能揭示出江苏省次表层土壤湿度的季节变化特征,但是深层土壤湿度与观测仍有较大差距。在时间演变方面,ERA次表层土壤湿度与站点观测在研究时段内较为接近,EOF分析揭示出1979—2016年江苏省次表层土壤湿度存在区域一致型与南北偶极型两个主要的年代际变率模态。但是对于深层土壤湿度时间演变而言,两种再分析资料都与观测有较大的差距。总体而言,再分析资料的次表层土壤湿度与站点观测较为接近,但是由于再分析资料陆面模式中地下水等影响深层土壤湿度的关键过程刻画较为简单,使得深层土壤湿度与观测有较大的差距。 相似文献
8.
热带气旋潜势指数是定量表征影响热带气旋生成的大尺度环境条件指标,在不能显式模拟热带气旋的气候系统模式中,常被作为热带气旋的代用指标。基于中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室发展的AGCM GAMIL2.0模式在历史海温驱动下的积分结果,评估了该模式对热带气旋潜势气候态、季节循环和年际变率的模拟能力。并分别从影响热带气旋潜势分布的热力因子(相对湿度、热带气旋最大风速)和动力因子(垂直风切变、绝对涡度、垂直抬升速度)的角度,讨论了造成热带气旋潜势模拟误差的原因。结果表明,在西北太平洋地区,模式能够合理再现热带气旋潜势的气候态分布,但由于GAMIL2.0模拟的相对湿度偏大且向东延伸,造成了热带气旋潜势大值区较之再分析资料偏大且偏东10°。由于GAMIL2.0模拟的季风槽位置偏北偏强,导致模拟的热带气旋潜势季节循环北进偏早而南退偏晚。在年际变化方面,GAMIL2.0能合理模拟出热带气旋潜势在ENSO正负位相东西反向的变化特征,但位于20°—30°N的加强和减弱区的分界线偏西,这与模拟的垂直速度和相对湿度的模拟误差有关,进一步分析表明,这是由于模拟中ENSO事件期间的西北太平洋异常上升中心比观测偏西且偏强造成的。 相似文献
9.
10.
采用恒定的现代外部强迫驱动第一版NUIST地球系统模式,进行了40年全球热带气旋活动模拟,分析了热带气旋活动的气候特征,并与1977—2016年观测资料对比分析。结果表明：该模式能够模拟出与热带气旋类似的结构特征,在热带气旋活动活跃的海区,模拟热带气旋生成的空间分布和影响范围与观测基本一致,但是各个海区热带气旋的生成频数与观测还存在差异。除了北印度洋海区,各个海区热带气旋生成频数的季节变化与观测相似。模式在西北太平洋海区模拟结果最好,能模拟出热带气旋的生成范围和盛行路径;在北印度洋地区模拟结果较差,北印度洋海区的相对涡度模拟与观测存在较大差异,这是模式未能模拟出北印度洋热带气旋双峰特征的主要原因。 相似文献
11.
利用1981—2020年气象台站的实测降水数据,对CRA40、ERA5、JRA55和MERRA2这4种再分析月降水数据在内蒙古地区的降水分布特征,与实测降水的相关性和误差进行分析。结果表明：（1）内蒙古地区4种再分析降水数据的空间分布与台站降水基本一致,误差分析表明CRA40与MERRA2的数据质量较高,ERA5次之,而JRA55数据质量相对较差。（2）CRA40和MERRA2在1983—1986年存在明显的降水低估,ERA5在2005年之后的内蒙古中东部出现明显的降水低估,JRA55在115°E以东存在明显降水高估,在115°E以西则以降水低估为主。（3）4种再分析月降水数据的年内最大均方根误差和绝对误差均集中在6—8月,与台站降水相关系数的年内最小值均出现在7月,内蒙古夏季汛期是再分析降水误差产生的主要时段。 相似文献
12.
Myong-In Lee Siegfried D. Schubert Dongmin Kim 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(3):245-253
This study examines the tropical storms simulated in the Modern-Era Retrospective analysis for Research and Applications (MERRA) global atmospheric reanalysis for the recent 12 years (1998–2009), focusing on the tropical storm activity over the Northwestern Pacific. For validation, the International Best Track Archive for Climate Stewardship (IBTrACS) dataset is used as an observational counterpart. Climatological-mean features of the tropical storm genesis, tracks and their maximum intensity are the primary interests in this study. Regarding the genesis location of tropical storms, MERRA is reasonable in resolving major development regions over the South China Sea and the Northwestern Pacific close to the Philippines. The seasonal variation of the number of storms is also reproduced in a realistic way in MERRA, with peak values occurring from July to September. In addition, MERRA tends to reproduce the observed interannual variation of the number of tropical storms during the 12-years, though with a limited accuracy. The simulated paths toward higher latitudes are also reasonable in MERRA, where the reanalysis corresponds well with the observations in resolving frequent paths of westward moving storms and recurving storms toward the northeast. Regarding the intensity, MERRA captures the linear relationship between the minimum center pressure and the maximum wind speed near the surface at the maximum development. Some discrepancies from the observed features are found in the reanalysis, such as less frequent development of storms over the South China Sea and less frequent paths over this region. The reanalysis also does not attain the observed maximum intensity for the resolved tropical storms, particularly underestimating the center pressure. These deficiencies are likely related to limitations in the horizontal resolution and the parameterized physics of the data assimilation system. 相似文献
13.
Tropical cyclone(TC) genesis over the western North Pacific(WNP) is analyzed using 23 CMIP5(Coupled Model Intercomparison Project Phase 5) models and reanalysis datasets. The models are evaluated according to TC genesis potential index(GPI). The spatial and temporal variations of the GPI are first calculated using three atmospheric reanalysis datasets(ERA-Interim, NCEP/NCAR Reanalysis-1, and NCEP/DOE Reanalysis-2). Spatial distributions of July–October-mean TC frequency based on the GPI from ERA-interim are more consistent with observed ones derived from IBTr ACS global TC data. So, the ERA-interim reanalysis dataset is used to examine the CMIP5 models in terms of reproducing GPI during the period 1982–2005. Although most models possess deficiencies in reproducing the spatial distribution of the GPI, their multimodel ensemble(MME) mean shows a reasonable climatological GPI pattern characterized by a high GPI zone along 20?N in the WNP. There was an upward trend of TC genesis frequency during 1982 to 1998, followed by a downward trend. Both MME results and reanalysis data can represent a robust increasing trend during 1982–1998, but the models cannot simulate the downward trend after 2000. Analysis based on future projection experiments shows that the GPI exhibits no significant change in the first half of the 21 st century, and then starts to decrease at the end of the 21 st century under the representative concentration pathway(RCP) 2.6 scenario. Under the RCP8.5 scenario, the GPI shows an increasing trend in the vicinity of20?N, indicating more TCs could possibly be expected over the WNP under future global warming. 相似文献
14.
为比较中国探空观测与再分析气温的差异,利用中国118站850—30 hPa经质量控制和均一化处理后逐月气温和NCEPv1、NCEPv2、ERA-40、ERA-Interim、JRA55、20CR、MERRA和CFSR等8套再分析月平均气温,通过对比1981—2010年探空观测与多套再分析气温序列的平均偏差、相关系数、标准差和变化趋势,分析两者在数值、年际变率、离散度及长期变化的差异。结果表明,中国探空温度原始序列存在较为显著的非均一性,均一化对原始气温序列总体为负订正,对流层上层至平流层下层(200—100 hPa)订正值最为显著。均一化气温去除了原始序列中由仪器换型和系统升级等因素导致的系统误差,与再分析气温相关较原始序列明显提高。再分析气温与均一化气温偏差约1℃,多数再分析气温较均一化气温在对流层偏低、平流层偏高。再分析与均一化气温年际变率较为一致,正相关达到显著。多数再分析与均一化气温均在对流层中低层呈上升趋势、平流层中层呈下降趋势。对流层上层和平流层下层不确定性较大。总体上,ERA-Interim、JRA55和MERRA与其他再分析相比更相近中国均一化探空气温。 相似文献
15.
Comparison of surface variables from ERA and NCEP reanalysis with station data over eastern China 总被引：2，自引：1，他引：1
Zhaofei Liu Zongxue Xu Zhijun Yao Heqing Huang 《Theoretical and Applied Climatology》2012,107(3-4):611-621
This study compared precipitation, mean air temperature (MAT) and mean sea level pressure (MSLP) from two widely used reanalysis datasets (ERA-40 and NCEP) with those from observed stations across eastern China. The evaluation was based on a comparison of both temporal and spatial variability and included several assessment criteria such as the mean values, normalized root mean square error, Mann–Kendall test, empirical orthogonal functions (EOFs) and probability density functions. The results showed that both the ERA-40 and NCEP datasets could capture temporal and spatial variability of the observed precipitation, MAT and MSLP over eastern China. The results showed that the two reanalysis datasets performed better for MAT and MSLP than for precipitation. Overall, the two reanalysis datasets revealed reasonable agreement with observations according to the evaluation. ERA-40 was better at capturing the temporal and spatial distributions for these three variables than NCEP, especially for MAT and MSLP. NCEP tended to overestimate the annual precipitation for both mean and extreme values, while ERA-40 tended to underestimate it, particularly for extreme values. The two reanalysis datasets performed better in the east and northeast regions of the study area than in other regions for capturing the temporal variability of MAT and MSLP. ERA-40 was poor at capturing the temporal variability of precipitation in northeastern China. According to the trend analysis, the two reanalysis datasets showed lower trends for MAT and precipitation and higher trends for MSLP. Both ERA-40 and NCEP had larger explained variances for the first two EOFs than the observed precipitation. This implies that both reanalysis datasets tend to simulate a more uniform spatial distribution for precipitation in the study area. 相似文献
16.
Tropical Cyclone Genesis Potential Index over the Western North
Pacific Simulated by LASG/IAP AGCM 
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下载免费PDF全文 Tropical cyclone genesis potential index(GPI) is a useful metric for gauging the performance of global climate models in the simulation of tropical cyclone(TC) genesis.The performance of LASG/IAP AGCM GAMIL2.0 in the simulation of GPI over the western North Pacific(WNP) is assessed in this paper.Since GPI depends on large scale environmental factors including low-level vorticity at 850 hPa,relative humidity at 700 hPa,vertical wind shear between 850 and 200 hPa,maximum potential intensity(MPI),and vertical velocity,the bias of GPI simulation is discussed from the perspective of thermal and dynamical factors.The results are compared with the ECMWF reanalysis data(ERA40).The analyses show that both the climatological spatial pattern and seasonal cycle of GPI over the WNP are reasonably simulated by GAMIL2.0,but due to the overestimation of relative humidity,the simulated GPI extends to 170°E,about 10°east to that in the reanalysis data.It is demonstrated that the bias in the simulation of monsoon trough,which is about 5°north to the reanalysis,leads to an overestimation of GPI during May-June and September-October,but an underestimation during July-August.Over the WNP,the response of GPI to ENSO is well captured by GAMIL2.0,including the eastward(westward) shift of TC genesis location during El Nin o(La Nin a) years.However,the anomalous convective center associated with El Nin o shifts westward about 20°in comparison to ERA40,which leads to the biases in both vertical velocity and relative humidity.These eventually result in the westward deflection of the boundary between the positive and negative GPI centers along 20°-30°N.The results from this study provide useful clues for the future improvement of GAMIL2.0. 相似文献
17.
Using tropical cyclone （TC） observations over a 58-yr period （1949-2006） from the China Meteorological Administration, the 40-year ECMWF Reanalysis （ERA-40）, NCEP-NCAR reanalysis, and the Hadley Centre sea ice and sea surface temperature （HadISST） datasets, the authors have examined the behaviors of tropical cyclones （TCs） in the western north Pacific （WNP） in boreal winter （November-December-January-February）. The results demonstrate that the occurrences of wintertime TCs, including super typhoons, have decreased over the 58 years. More TCs are found to move westward than northeastward, and the annual total number of parabolic-track-type TCs is found to be decreasing. It is shown that negative sea surface temperature anomalies （SSTAs） related to La Nifia events in the equatorial central Pacific facilitate more TC genesis in the WNP region. Large-scale anomalous cyclonic circulations in the tropical WNP in the lower troposphere are observed to be favorable for cyclogenesis in this area. On the contrary, the positive SSTAs and anomalous anticyclonic circulations that related to E1 Nifio events responsible for fewer TC genesis. Under the background of global warming, the western Pacific subtropical high tends to intensify and to expand more westward in the WNP, and the SSTAs display an increasing trend in the equatorial eastern-central Pacific. These climate trends of both atmospheric circulation and SSTAs affect wintertime TCs, inducing fewer TC occurrences and causing more TCs to move westward. 相似文献
18.
Validation of ECMWF and NCEP–NCAR Reanalysis Data in Antarctica 总被引：3，自引：0，他引：3
YU Lejiang ZHANG Zhanhai ZHOU Mingyu Shiyuan ZHONG Donald LENSCHOW Hsiaoming HSU WU Huiding SUN Bo 《大气科学进展》2010,27(5):1151-1168
The European Center for Medium-Range Weather Forecast (ECMWF) Re-Analysis (ERA-40) and the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) ECMWF (ERA-40) and NCEP-NCAR reanalysis data were compared with Antarctic station observations, including surface-layer and upper-layer atmospheric observations, on intraseasonal and interannual timescales. At the interannual timescale, atmospheric pressure at different height levels in the ERA-40 data are in better agre... 相似文献