改进月延伸预报的一种方法   总被引：17，自引：2，他引：17  

张培群  导纪范 《高原气象》1997,16(4):376-388

  相似文献   

季节性波浪动力作用下南湾弧形岸滩泥沙横向输运特征     

戴志军  陈建勇  李春初  王世俊  路海亭 《海洋工程》2007,25(4):39-45

响应季节性波候作用的泥沙输运特征是研究弧形海滩地貌变化及港工建筑的重要内容。基于南湾弧形海滩实际测量的冬、夏各11条剖面高程变化资料,将其划分为低潮间带、低中潮带、中潮带、高潮间带、低冲流带、中冲流带及其海滩后滨等7带,在此基础上利用经验正交函数(EOF)方法对各个带的体积变化进行分析,结果表明:1)南湾弧形海滩的泥沙以单向输运为主,并具有季节性变化特征,其中冬季泥沙在东南浪作用下,自陆向海输运,夏季泥沙在西南浪作用下自海向陆输运;2)南湾弧形海滩的泥沙分别在高潮带与中潮带、低冲流带与中冲流带之间存在频繁的双向输运;3)南湾弧形海滩不同岸段泥沙的横向输运因岬角的遮蔽能力、地形以及波浪作用的方向而有所差异。  相似文献   

基于TOPEX/Poseidon资料的南海海面高度场的时空特征分析   总被引：1，自引：0，他引：1  

王静  齐义泉  施平  毛庆文  朱伯承 《热带海洋学报》2003,22(4):26-33

采用经验正交函数(EOF)分解方法，对TOPEX／Poseidon卫星高度计在南海获得的1992年10月到1999年9月约7a的海面高度观测资料进行分析，从而获得南海海面高度距平场典型的空间分布型态及其对应的时间变化特征。结果表明，南海海面高度距平场在空间上主要表现为两种典型的分布结构：(1)由于冬、夏季风反转造成海盆尺度的涡旋结构，这种分布结构对南海海面高度距平场的方差贡献达27．46％；(2)NE—SW即吕宋—越南反相双涡结构，其方差贡献达20．37％。这两个模态都明显反映了季风的反转以及季风结构所造成的影响。同时，对各空间典型场所对应的时间系数序列进行了傅立叶谱分析，结果表明南海海面高度距平场存在多种时间尺度的变化。  相似文献   

黑潮区域海温异常与我国冬季气温和降水的关系   总被引：1，自引：0，他引：1       下载免费PDF全文

赵斐苗朱鑫君  李飞王志强  谷继永王美兰 《气象与环境科学》2007,30(B09):28-31

利用NOAA提供的延长重构（extended reconstructed）的月平均海表温度场等资料，采用相关分析和经验正交函数分解等方法，探讨冬季黑潮SSTA与我国冬季气温及降水的相关性，结果表明：冬季黑潮SSTA具有整体一致的空间变化特征，冬季黑潮区域海温与我国冬季气温存在较好的相关性，当黑潮海域海温升高（降低）时，会出现全国范围的升（降）温现象；冬季黑潮区域海温与我国冬季降水存在一定的相关性，具有明显的区域分布特征。  相似文献   

A Medium/Long-Range Forecast of Pacific Subtropical High Based on Dynamic Statistic Model Reconstruction          下载免费PDF全文

洪梅  张韧  刘科峰  余丹丹 《Acta Meteorologica Sinica》2007,21(3):376-384

Based on the 500-hPa geopotential height field series of T106 numerical forecast products,by empirical orthogonal function(EOF)time-space separation,and on the hypotheses of EOF space-models being stable, the EOF time coefficient series were taken as dynamical statistic model variables.The dynamic system reconstruction idea and genetic algorithm were introduced to make the dynamical model parameters opti- mized,and a nonlinear dynamic statistic model of EOF separating time coefficient series was established.By the model time integral and EOF time-space reconstruction,a medium/long-range forecast of subtropical high was carried out.The results show that the dynamical model forecast and T106 numerical forecast were approximately similar in the short-range forecast(≤5 days),but in the medium/long-range forecast (≥5 days),the forecast results of dynamical model was superior to that of T106 numerical products.A new method and idea were presented for diagnosing and forecasting complicated weathers such as subtropical high,and showed a better application outlook.  相似文献   

黑潮区域海温异常与我国冬季气温和降水的关系     

赵斐苗  朱鑫君  李飞  王志强  谷继永  王美兰 《河南气象》2007,(Z1)

利用NOAA提供的延长重构(extended reconstructed)的月平均海表温度场等资料,采用相关分析和经验正交函数分解等方法,探讨冬季黑潮SSTA与我国冬季气温及降水的相关性,结果表明:冬季黑潮SSTA具有整体一致的空间变化特征,冬季黑潮区域海温与我国冬季气温存在较好的相关性,当黑潮海域海温升高(降低)时,会出现全国范围的升(降)温现象;冬季黑潮区域海温与我国冬季降水存在一定的相关性,具有明显的区域分布特征。  相似文献   

云南汛期旱涝特征及成因分析   总被引：3，自引：0，他引：3  

段长春  朱勇  尤卫红 《高原气象》2007,26(2):402-408

通过Z指数和旋转经验正交函数(REOF)分析等对云南省汛期(5~10月)降水作旱涝等级划分、型态分布和旱涝时空分布特征研究,发现云南省各地汛期降水具有一致性,1980年代以来,汛期旱涝有更频繁发生的趋势,东、西部和东南部地区为云南省全省旱涝多发区。对比分析了云南旱涝年的大气环流特征,发现两者显著差异:涝年500 hPa位势高度距平亚洲区域自西向东为“- -”波列结构,云南北部低槽活跃,反映出有强冷空气活动的环流背景,伊朗高压及青藏高压活跃,利于与副热带高压形成“两高辐合”的强降水形势;低层850 hPa水汽输送和OLR场特征揭示出低纬度热带海洋具有强烈的水汽输送机制;旱年则反之。并讨论了导致云南汛期旱涝的热带强迫源区主要位于孟加拉湾、南海—西太平洋,可能机制是热带强迫所激发的大尺度准定常波列的传播。  相似文献   

SPATIAL/TEMPORAL FEATURES OF DROUGHT/FLOOD IN FUJIAN FOR THE PAST FOUR DECADES     

游立军  高建芸  邓自旺  周晓兰  张容焱 《热带气象学报(英文版)》2007,13(1):45-48

41a (1961 - 2001) seasonal Z index series of 25 representative weather stations are investigated by virtue of EOF, FFT, continuous wavelet transformation (CWT) and orthogonal wavelet transformation (OWT). It shows that: (1) Fujian drought/flood (DF) has a significant 2 - 3a cycle for the periods 1965 - 1975 and 1990's; (2) the pattern, which represents the opposite DF trend between the southern and northern parts, has 1a and 3 - 4a cycles since the middle of 1980's; (3) EOF3, which denotes the reverse change between the middle-west region and other areas, has significant 1 - 2a cycle for the period from 1985 to 1998 and 9 - 13a cycle since 1980s; (4) there is an obvious drought trend for the last 40a (especially in the 1990's), which is more outstanding in the south (east) than in the north (west); (5) the 1960's and 1980's are in relatively wet phases and the 1970's and 1990's are in drought spells.  相似文献   

Streamflow trends and hydrological response to climatic change in Tarim headwater basin     

JIANG Yan  ZHOU Chenghu  CHENG Weiming 《地理学报》2007,17(1):51-61

This paper has studied the change of streamflow and the impact of climatic vari-ability conditions on regional hydrological cycle in the headwater of the Tarim River Basin. This study investigates possible causes of observed trends in streamflow in an environment which is highly variable in terms of atmospheric conditions, and where snow and ice melt play an important role in the natural hydrological regime. The discharge trends of three head streams have a significant increase trend from 1957 to 2002 with the Mann–Kendall test. Complex time-frequency distributions in the streamflow regime are demonstrated especially by Morlet wavelet analysis over 40 years. The purpose is to ascertain the nature of climatic factors spatial and temporal distribution, involved the use of EOF (Empirical Orthogonal Function) to compare the dominant temperature, precipitation and evaporation patterns from normally climatic records over the Tarim’s headwater basin. It shows that the first principal component was dominated since the 1990s for temperature and precipitation, which identifies the significant ascending trend of spatial and temporal pattern characteristics under the con-dition of the global warming. An exponential correlation is highlighted between surface air temperature and mean river discharge monthly, so the regional runoff increases by 10%–16% when surface air temperature rises by 1℃. Results suggest that headwater basins are the most vulnerable environments from the point of view of climate change, because their wa-tershed properties promote runoff feeding by glacier and snow melt water and their funda-mental vulnerability to temperature changes affects rainfall, snowfall, and glacier and ice melt.  相似文献   

Comparison between the two triggered landslides in Mid-Niigata, Japan by July 13 heavy rainfall and October 23 intensive earthquakes in 2004   总被引：3，自引：2，他引：3  

Hiromitsu Yamagishi  Junko Iwahashi 《Landslides》2007,4(4):389-397

On July 13, 2004, heavy rainfalls because of the intensive activities of the rain front occurred in the Mid-Niigata Region, Japan. They were as much as 400 mm in 24 h, bringing about serious flooding by breaking the river banks. The heavy rainfalls also triggered more than 3,500 landslides. Three months later, the southern region of Mid-Niigata was attacked by an earthquake of magnitude 6.8 on the Richter scale on October 23, 2004. The main earthquakes were followed by intensive aftershocks, which continued until December 2004. By these earthquakes, variable landslides of more than 4,400 also occurred in the hilly and mountainous areas. Namely, different triggers brought about the variable landslides in the hilly mountains whose features are very similar in geological and geomorphological points of view. Therefore, these two events are very useful for clearing the difference in features of the landslides between the two. We have been researching on both landslides in the field just after both occurred and later analyzing air photographs using the geographic information system (GIS). In this paper, we describe the comparison in the distribution features using GIS analytical data between the heavy rainfall-induced and the intensive earthquake-induced landslides.  相似文献