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1.
西太平洋暖池海温对华南前汛期降水影响的数值试验 总被引：14，自引：10，他引：14
简要地介绍了全球大气环流模式CCM3,由该模式模拟得到降水、位势高度场和风场,分析它的模拟性能。根据华南前汛期(4～6月)降水与西太平洋暖池敏感海区(西区)海温的负相关关系,设计了两组敏感性试验,讨论西区海温对华南前汛期降水影响的确定性和可能的物理机制。模拟结果表明,当西区为冷水年(暖水年)时,华南降水偏多(少),长江中下游相对偏少(多),相关最好的地区是广东省,与诊断分析结果相符。海温对降水的影响是通过大气环流场来实现的,因此,再用P-σ九层区域气候模式模拟了西区海温异常年大气环流对华南前汛期降水的影响,与CCM3模拟结果基本一致。 相似文献
2.
利用NOAA（National Oceanic and Atmospheric Administration）海温、GPCP（Global Precipitation Climatology Project）降水和ERA-20C（ECMWF's first atmospheric reanalysis of the 20th century）再分析大气环流资料,结合大气环流模式ECHAM5敏感性试验,研究了与秋季印度洋海温偶极子模态（IOD）相联系的冬季热带西太平洋海温异常型及其对东亚冬季气候的影响。发现在秋季发生IOD背景下,冬季西太平洋存在两类海温异常的变化型:一类是西太平洋区域一致偏暖/冷的模态,另一类是区域西冷东暖/西暖东冷的模态。尽管西太平洋海温一致偏暖和西冷东暖这两类海温变化型均有利于华南冬季少降水,但影响的范围有所不同。一致偏暖型引起的少降水范围较大,从华南扩展到长江中下游地区。西冷东暖型引起少降水范围主要限于华南,而在长江中下游到华北则降水偏多。相应地,在大气环流上,尽管两类海温异常型均有利于在西北太平洋菲律宾海附近出现气旋式环流异常,但气旋的强度和中心位置有差异。一致偏暖型引起的气旋偏强,中心位置偏西,其后部异常东北风控制的范围更大,导致少降水范围更大,而西冷东暖型引起的气旋偏弱,中心位置偏东,其后部异常东北风控制的范围小,导致少降水区域主要在华南沿海。本文结果对认识IOD调制随后冬季东亚降水异常的机理有重要意义。 相似文献
3.
Guangzhou spring rainfall mainly exhibits interannual variation of Quasi-biannual and
interdecadal variation of 30 yrs, and is in the period of weak rainfall at interdecadal time scale.
SST anomalies (SSTA) of Nino3 are the strongest precursor of Guangzhou spring rainfall. They
have significant positive correlation from previous November and persist stably to April. Nino3
SSTA in the previous winter affects Guangzhou spring rainfall through North Pacific subtropical
high and low wind in spring. When Nino3 SSTA is positive in the previous winter, spring
subtropical high is intense and westward, South China is located in the area of ascending airflow at
the edge of the subtropical high, and water vapor transporting to South China is intensified by
anticyclone circulation to the east of the Philippines. So Guangzhou spring rainfall is heavy. When
Nino3 SSTA is negative, the subtropical high is weak and eastward, South China is far away from
the subtropical high and is located in the area of descending airflow, and water vapor transporting
to South China is weak because low-level cyclonic circulation controls areas to the east of the
Philippines and north wind prevails in South China. So Guangzhou spring rainfall is weak and
spring drought is resulted. 相似文献
4.
Based on an observational analysis, seven numerical experiments are designed to study the impacts of Pacific SSTA on summer precipitation over eastem China and relevant physical mechanism by NCAR CCM3. The numerical simulation results show that preceding winter SSTA in the Kuroshio region leads to summer precipitation anomaly over the Yangtze River valleys by modifying atmospheric general circulation over eastern Asia and middle-high latitude. West Pacific subtropical high is notably affected by preceding spring SSTA over the middle and east of Equator Pacific; SSTA of the central region of middle latitude in the corresponding period causes the summer rainfall anomaly over eastern China so as to trigger the atmospheric Eurasia-Pacific teleconnection pattern. 相似文献
5.
Based on an observational analysis, seven numerical experiments are designed to study the impacts of Pacific SSTA on summer precipitation over eastem China and relevant physical mechanism by NCAR CCM3. The numerical simulation results show that preceding winter SSTA in the Kuroshio region leads to summer precipitation anomaly over the Yangtze River valleys by modifying atmospheric general circulation over eastern Asia and middle-high latitude. West Pacific subtropical high is notably affected by preceding spring SSTA over the middle and east of Equator Pacific; SSTA of the central region of middle latitude in the corresponding period causes the summer rainfall anomaly over eastern China so as to trigger the atmospheric Eurasia-Pacific teleconnection pattern. 相似文献
6.
Based on an observational analysis, seven numerical experiments are designed to study the impacts of Pacific SSTA on summer precipitation over eastern China and relevant physical mechanism by NCAR CCM3. The numerical simulation results show that preceding winter SSTA in the Kuroshio region leads to summer precipitation anomaly over the Yangtze River valleys by modifying atmospheric general circulation over eastern Asia and middle-high latitude. West Pacific subtropical high is notably affected by preceding spring SSTA over the middle and east of Equator Pacific; SSTA of the central region of middle latitude in the corresponding period causes the summer rainfall anomaly over eastern China so as to trigger the atmospheric Eurasia-Pacific teleconnection pattern. 相似文献
7.
Phase composite analyses are conducted to investigate the possible effect of the Madden–Julian oscillation(MJO)on the spring rainfall anomalies in East China by using the Real-time Multivariate MJO(RMM)index from Australian Meteorological Bureau.The results show that the rainfall anomalies over the mid-and lower-valley of Yangtze River are positive when the MJO shifts eastward to the mid-and eastern-Indian Ocean,and anomalous precipitation over South China are positive when the MJO moves further eastward to the maritime continent,whereas spring rainfall anomalies over East China are negative in the other MJO episodes.The MJO impacts on the precipitation over East China result from the changes in large-scale atmospheric circulation as well as vorticity and water vapor transportation in the mid-and lower-troposphere. 相似文献
8.
利用1961—2017年中国地面观测站日降水资料、全球大气多要素和海表温度月资料,分析华南区域持续性强降水过程的气候特征,诊断并比较与华南前汛期、后汛期区域持续性强降水年际变化相关的大气环流和海表温度异常特征。结果表明,3—12月华南都可能出现持续性强降水过程,其中汛期4—9月的占了94.4%。伴随着区域持续性强降水的年际变化,华南本地垂直上升运动显著异常是前汛期和后汛期的共同点,但前汛期、后汛期在华南及周边环流异常、水汽输送来源以及海温异常分布等方面都存在一定差异。在前汛期华南区域持续性强降水偏重年,赤道西太平洋区域海温偏低,由于大气罗斯贝波响应使西太平洋副热带高压偏强,热带西太平洋向华南区域水汽输送加强,从而有利于区域持续性强降水偏重。后汛期华南区域持续性强降水偏重年的海温异常分布是赤道中东太平洋区域正异常、东印度洋至西太平洋暖池区负异常,海温异常通过西北太平洋副热带高压、南海热带季风强度、水汽输送和垂直环流等多方面,导致后汛期区域持续性强降水偏重。 相似文献
9.
10.
With the methods of REOF (Rotated Empirical Orthogonal Function), the summer precipitation from 43 stations over eastern China for the 1901 - 2000 period was examined. The results show that South China and Southwest China, the middle and lower reaches of Changjiang River, North China and the southwestern of Northeast China are the three main areas of summer rainfall anomaly. Furthermore, correlation analysis is used in three time series of three mostly summer rainfall modes and four seasonal Pacific SSTA (Sea Surface Temperature Anomaly), and the results suggest that the Pacific SSTA which notably causes the summer rainfall anomaly over eastern China are the SSTA of the preceding winter over Kuroshio region of Northwest Pacific, SSTA of the preceding spring in the eastern and central equatorial Pacific, and SSTA of the current summer in the central region of middle latitude. The relationship between summer precipitation over eastern China and SSTA of Pacific key regions was further verified by SVD (Singular Value Decomposition) analysis.The composite analysis was used to analyze the features of atmospheric general circulation in the years of positive and negative precipitation anomaly. Its results were used to serve as the base of numerical simulation analysis. 相似文献
11.
With the methods of REOF (Rotated Empirical Orthogonal Function), the summer precipitation from 43 stations over eastern China for the 1901 - 2000 period was examined. The results show that South China and Southwest China, the middle and lower reaches of Changjiang River, North China and the southwestern of Northeast China are the three main areas of summer rainfall anomaly. Furthermore, correlation analysis is used in three time series of three mostly summer rainfall modes and four seasonal Pacific SSTA (Sea Surface Temperature Anomaly), and the results suggest that the Pacific SSTA which notably causes the summer rainfall anomaly over eastern China are the SSTA of the preceding winter over Kuroshio region of Northwest Pacific, SSTA of the preceding spring in the eastern and central equatorial Pacific, and SSTA of the current summer in the central region of middle latitude. The relationship between summer precipitation over eastern China and SSTA of Pacific key regions was further verified by SVD (Singular Value Decomposition) analysis.The composite analysis was used to analyze the features of atmospheric general circulation in the years of positive and negative precipitation anomaly. Its results were used to serve as the base of numerical simulation analysis. 相似文献
12.
Based on the data of SST and NCEP/NCAR reanalysis data, the relationship is analyzed of spring SSTA in the Kuroshio region with summer precipitation in China, summer 500 hPa field and water vapor transport, using the methods of Morlet wave, correlation and composite analysis. The results show that annual and interdecadal change of spring SST in the Kuroshio region is distinct. Spring SST displays a significantly increasing trend and there exist different periodic oscillations in the Kuroshio region, with the 23-year periodic oscillation being the most obvious. Troughs and ridges in the mid- and higher- latitudes turn deeper in high Kuroshio SSTA years. At the same time, the western Pacific subtropical high strengthens and stretches westwards. As a result, the warm / wet air from the west of the subtropical high locates in the mid- and lower- reaches of the Yangtze River and south China and summer rainfall in the above regions increases accordingly. Composite anomalous water vapor flux fields indicate that the vapor transport from the South China Sea and western Pacific and the vapor from the north converge over the mid- and lower- reaches of the Yangtze River and south China, which results in the increase of the summer rainfall in the mid- and lower- reaches of the Yangtze River and south China. On the contrary, the summer rainfall in the mid- and lower- reaches of the Yangtze River and south China decreases correspondingly in low Kuroshio SSTA years. 相似文献
13.
Based on the NCEP/NCAR reanalysis dataset and in situ meteorological observations of daily precipitation in boreal summer from 1979 to 2008, the features of circulation anomalies have been investigated using the composite analysis for the extreme events and non-extreme events of regional mean daily rainfall(RMDR) occurring over the midand lower- Yangtze valley(MLYV). The extreme RMDR(ERMDR) events are the events at and above the percentile99 in the rearranged time-series of the RMDR with ascending order of rainfall amount. The non-extreme RMDR events are those at the percentiles 90-85 and 80-75 separately. Our results suggest that the threshold value is 25 mm/day for the ERMDR at percentile 99. Precipitation at all the percentiles is found to occur more frequently in the Meiyu rainfall season in MLYV, and the ERMDR events have occurred with higher frequency since the 1990 s. For the percentiles-associated events, the MLYV is under the control of an anomalous cyclonic circulation in the mid- and lower- troposphere with vastly different anomalous circulation at higher levels. However, at both low and high levels, the ERMDR events-related anomalous circulation is stronger compared to that linked to the non-ERMDR events. The dominant sources of water vapor differ between the ERMDR and non-ERMDR events. During the ERMDR events plentiful water vapor is transported from the Bay of Bengal into the MLYV directly by divergence while there is distinctly increased water vapor from the South China Sea(SCS) in non-RMERMDR episodes. The diabatic heating rates < Q1>, < Q2> and< Q1>- < Q2> have their anomalous patterns and are consistent with each other for these percentiles but their strength decreases markedly with the drop of rainfall intensity. For the precipitation at percentiles 99 and 90-85, the sea surface temperature anomalies(SSTA) in the Pacific distribute positively(negatively) in the south(north), and are stronger when the ERMDR emerges, with little or no SSTA as the events at percentile 80-75 occur. Besides, these results suggest that the genesis of the ERMDR event is directly related to intense local circulation anomalies and the circulation anomalies over the Pacific and SCS in tropical to mid-latitudes, and probably linked with the Pacific SSTA closely while the non-ERMDR events are mainly associated with the anomalous circulation on a local basis. The findings here help understand and predict the happening of ERMDR events over the MLYV. 相似文献
14.
山东夏季降水的气候特征及其成因 总被引：2，自引：0，他引：2
用GMS TBB和ECMWF的格点风资料,采用带通滤波、EOF分解和合成分析方法,对湖北省洪涝年出现“二度梅”年(1980、1998年)和无“二度梅”年(1991、1999年)的南海和青藏高原TBB的低频振荡特征进行了分析研究。结果表明:有(无)“二度梅”年,南海低频TBB在6～7月的振荡位相是相反的;在7月下旬～8月上旬,南海低频TBB为高(低)值位相,青藏高原低频TBB为低(高)值位相。南亚地区低频TBB场EOF1的空间分布形式呈“南负北正”(南正北负)。 相似文献
15.
EXTRA-SEASONAL PREDICTIONS OF SUMMER RAINFALL IN CHINA AND ENSO IN 2001 BY CLIMATE MODELS 总被引：3，自引：0，他引：3
China is a monsoon country.The most rainfalls in China concentrate on the summer seasons.More frequent floods or droughts occur in some parts of China.Therefore,the prediction ofsummer rainfall in China is a significant issue.As we know,the obvious impacts of the sea surfacetemperature anomalies(SSTA)on the summer rainfall over China have been noticed.Thepredictions of the SSTA have been involved in the research.The key project on short-term climate modeling prediction system has been finished in 2000.The system included an atmospheric general circulation model named AGCM95,a coupledatmospheric-oceanic general circulation model named AOGCM95,a regional climate model overChina named RegCM95,a high-resolution Indian-Pacific OGCM named IPOGCM95,and asimplified atmosphere-ocean dynamic model system named SAOMS95.They became theoperational prediction models of National Climate Center(NCC).Extra-seasonal predictions in 2001 have been conducted by several climate models,which werethe AGCM95,AOGCM95,RegCM95,IPOGCM95,AIPOGCM95,OSU/NCC,SAOMS95,IAPAPOGCM and CAMS/ZS.All of those models predicted the summer precipitation over China and/or the annual SSTA over the tropical Pacific Ocean in the Modeling Prediction Workshop held inMarch 2001.The assessments have shown that the most models predicted the distributions of main rain beltover Huanan and parts of Jiangnan and droughts over Huabei-Hetao and Huaihe River Valleyreasonably.The most models predicted successfully that a weaker cold phase of the SSTA over thecentral and eastern tropical Pacific Ocean would continue in 2001.The evaluations of extra-seasonal predictions have also indicated that the models had a certaincapability of predicting the SSTA over the tropical Pacific Ocean and the summer rainfall overChina.The assessment also showed that multi-model ensemble(super ensembles)predictionsprovided the better forecasts for both SSTA and summer rainfall in 2001,compared with the singlemodel.It is a preliminary assessment for the extra-seasonal predictions by the climate models.Thefurther investigations will be carried out.The model system should be developed and improved. 相似文献
16.
影响华南后汛期季风持续性暴雨和热带气旋持续性暴雨的大尺度环流背景分析 总被引：6，自引：1，他引：6
利用1961—2008年NCEP逐日、逐月再分析资料和全国和华南各省台站逐日降水资料,得到华南后汛期持续性暴雨74例,其中热带气旋 (TC) 引起的持续性暴雨 (TCR) 有54例,季风引起的持续性暴雨 (MSR) 有20例。TCR主要发生在8月,占TCR总数的52%,MSR主要发生在7月,占MSR总数的70%。两类持续性暴雨的出现次数具有明显的年代际变化特征,自1980年代以来发生的次数明显增加。通过对比分析得到,MSR主要由前期和同期热带中东太平洋异常海温持续偏暖所致,其一方面加强了南海夏季风环流、水汽辐合异常增强;另一方面增强了菲律宾海的对流,使得高空西风急流位置偏北;在两者的共同作用下,大气环流激发出“-、+、-”的EAP遥相关型波列分布,为7月持续性暴雨的发生提供有利条件。相比之下,TCR主要由于8月局地海温-黑潮区海温异常偏冷致使高空西风急流位置偏北所致。此外,叠加在这种尺度背景下,导致MSR和TCR发生的关键是10~20天季节内振荡导致系统由东南向西北传播。 相似文献
17.
The impact of strong (weak) intraseasonal oscillation (ISO) over South China Sea (SCS) and South Asia (SA) in summer on the SCS and SA summer monsoon and the summer rainfall in Eastern China are studied by using the NCEP-NCAR analysis data and the rainfall data of 160 stations in China from 1961 to 2010. It is found that the impacts are significantly different in different months of summer. The study shows that in June and July cyclonic (anticyclonic) atmospheric circulation over SCS and SA corresponds to strong (weak) ISO over SCS. In August, however, strong (weak) ISO over SCS still corresponds to cyclonic (anticyclonic) atmospheric circulation over SA. In June and August cyclonic (anticyclonic) atmospheric circulation over South Asia corresponds to strong (weak) ISO over SA while a strong (weak) ISO corresponds to anticyclonic (cyclonic) atmospheric circulation over SA in July. Besides, in June the strong (weak) ISO over SA corresponds to cyclonic (anticyclonic) atmospheric circulation over SCS, while in July and August the atmospheric circulation is in the same phase regardless of whether the ISO over SA is strong or weak. The impacts of the strong（weak）ISO over SCS on the rainfall of eastern China are similar in June and July, which favors less (more) rainfall in Yangtze-Huaihe Rivers basin but sufficient (deficient) rainfall in the south of Yangtze River. However, the impacts are not so apparent in August. In South Asia, the strong (weak) ISO in July results in less (more) rainfall in the south of Yangtze River but sufficient (deficient) rainfall in Yangtze-Huaihe Rivers basin. The influence on the rainfall in eastern China in June and August is not as significant as in July. 相似文献
18.
EXTRA-SEASONAL PREDICTIONS OF SUMMER RAINFALL IN CHINA AND ENSO IN 2001 BY CLIMATE MODELS* 
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下载免费PDF全文 China is a monsoon country.The most rainfalls in China concentrate on the summer seasons.More frequent floods or droughts occur in some parts of China.Therefore,the prediction of summer rainfall in China is a significant issue.As we know,the obvious impacts of the sea surface temperature anomalies(SSTA)on the summer rainfall over China have been noticed.The predictions of the SSTA have been involved in the research.The key project on short-term climate modeling prediction system has been finished in 2000.The system included an atmospheric general circulation model named AGCM95,a coupled atmospheric-oceanic general circulation model named AOGCM95,a regional climate model over China named RegCM95,a high-resolution Indian-Pacific OGCM named IPOGCM95,and a simplified atmosphere-ocean dynamic model system named SAOMS95.They became the operational prediction models of National Climate Center(NCC).Extra-seasonal predictions in 2001 have been conducted by several climate models,which were the AGCM95,AOGCM95,RegCM95,IPOGCM95,AIPOGCM95,OSU/NCC,SAOMS95,IAP APOGCM and CAMS/ZS.All of those models predicted the summer precipitation over China and/or the annual SSTA over the tropical Pacific Ocean in the Modeling Prediction Workshop held in March 2001.The assessments have shown that the most models predicted the distributions of main rain belt over Huanan and parts of Jiangnan and droughts over Huabei-Hetao and Huaihe River Valley reasonably.The most models predicted successfully that a weaker cold phase of the SSTA over the central and eastern tropical Pacific Ocean would continue in 2001.The evaluations of extra-seasonal predictions have also indicated that the models had a certain capability of predicting the SSTA over the tropical Pacific Ocean and the summer rainfall over China.The assessment also showed that multi-model ensemble(super ensembles)predictions provided the better forecasts for both SSTA and summer rainfall in 2001,compared with the single model.It is a preliminary assessment for the extra-seasonal predictions by the climate models.The further investigations will be carried out.The model system should be developed and improved. 相似文献
19.
The relationship between summer rainfall anomalies in northeast China and two types of El Ni?o events is investigated by using observation data and an AGCM. It is shown that, for different types of El Ni?o events, there is different rainfall anomaly pattern in the following summer. In the following year of a typical El Ni?o event, there are remarkable positive rainfall anomalies in the central-western region of northeast China, whereas the pattern of more rainfall in the south end and less rainfall in the north end of northeast China easily appears in an El Ni?o Modoki event. The reason for the distinct differences is that, associated with the different sea surface temperature anomalies (SSTA) along the equatorial Pacific, the large-scale circulation anomalies along east coast of East Asia shift northward in the following summer of El Ni?o Modoki events. Influenced by the anomalous anticyclone in Philippine Sea, southwesterly anomalies over eastern China strengthens summer monsoon and bring more water vapor to Northeast China. Meanwhile, convergence and updraft is strengthened by the anomalous cyclone right in Northeast China in typical El Ni?o events. These moisture and atmospheric circulation conditions are favorable for enhanced precipitation. However, because of the northward shift, the anomalous anticyclone which is in Philippine Sea in typical El Ni?o cases shifts to the south of Japan in Modoki years, and the anomalous cyclone which is in the Northeast China in typical El Ni?o cases shifts to the north of Northeast China, leading to the “dipole pattern” of rainfall anomalies. According to the results of numerical experiments, we further conform that the tropical SSTA in different types of El Ni?o event can give rise to observed rainfall anomaly patterns in Northeast China. 相似文献
20.
Sensitivity experiments with atmospheric general circulation model CAM3 have been performed to investigate the atmospheric response to warm wintertime sea surface temperature anomalies in the Kuroshio Extension (KE). Mechanism for the sustaining abnormal atmospheric response to sea surface temperature anomaly (SSTA) is revealed. It is found that the warm wintertime SSTA in KE leads to soil moisture changes across the Asia continent. The abnormal soil moisture may possibly be one of the reasons for the sustaining of abnormal atmospheric response intrigued by SSTA. Oscillations of perturbations intrigued by warm wintertime SSTA in KE, which have similar frequencies with that of intrinsic atmospheric oscillations, are superposed on the atmospheric oscillations and propagate with primary periodic oscillation of the atmosphere. These SSTA-intrigued oscillations are coupled with natural atmospheric oscillation and finally become parts of it. This is probably another reason for the sustaining of abnormal atmospheric response to SSTA in KE. 相似文献