中国三大城市带城市化气候效应的检测与对比

利用国家基本、基准站1951—2009的逐日气候数据和1986—2008的城市人口资料,建立了一种新的城市化指标,分析了京津冀城市带、长江三角洲城市带和珠江三角洲城市带中典型城市及区域整体的城市化特征,对三个城市群区的城市气候特征和气候效应进行了比较。结果表明：城市化使典型城市的平均气温和最低气温显著升高,城市化气候效应特征可以分为“冷季型”、“暖季型”和“过渡季节型”三种类型。长三角地区的城市化气候效应最强,京津冀次之,珠三角最弱。长三角地区与京津冀地区城市化气候效应的共同点为平均气温和夜间气温升高,春、秋两季增温显著;不同点是长三角夏季强于冬季,最高气温明显升高,京津冀冬季强于夏季,最高气温无明显变化。城市化对降水的影响在三个城市群区有着不同的特点,主要体现在极端强降水事件上。     

春季青藏高原地区大气热源的气候特征分析

利用1948-2009年NCEP/NCAR逐日再分析资料采用倒算法计算了青藏高原地区大气热量源汇的值,分析了春季青藏高原地区大气热源的水平和垂直气候分布特征及时空变化特征.结果表明:春季青藏高原上空,大气热量源汇的整层积分为正值,即高原上空大气为热源,但在高原上空大气高层存在局部为冷源的分布.与周边地区相比较,高原对其上空大气的加热作用在三月份最为显著.春季3、4、5月青藏高原区域大气的加热存在一个自西向东逐渐扩展的过程.春季青藏高原东部和西部为大气热源年变化较大的区域,且高原东部和西部大气热源表现出反位相分布的特征.     

海南岛登陆热带气旋频数异常成因分析

采用NCEP／NCAR再分析的月平均500hPa高度场、海温场（SST）资料,分析讨论了登陆海南岛热带气旋活动异常与大气环流、SST影响因子之间的关系,得到登陆海南岛热带气旋（TC）偏多、偏少年对应的大气环流、SST的概念模型。分析结果表明：（1）前一年11月500hPa亚洲大陆高纬位势高度偏低（高）,则次年登陆海南岛...     

Long-Term Trend of Temperature Derived by Statistical Downscaling Based on EOF Analysis

This study analyzes the ability of statistical downscaling models in simulating the long-term trend of temperature and associated causes at 48 stations in northern China in January and July 1961–2006. The statistical downscaling models are established through multiple stepwise regressions of predictor principal components (PCs). The predictors in this study include temperature at 850 hPa (T850), and the combination of geopotential height and temperature at 850 hPa (H850+T850). For the combined predictors, Empirical Orthogonal Function (EOF) analysis of the two combined fields is conducted. The modeling results from HadCM3 and ECHAM5 under 20C3M and SERS A1B scenarios are applied to the statistical downscaling models to construct local present and future climate change scenarios for each station, during which the projected EOF analysis and the common EOF analysis are utilized to derive EOFs and PCs from the two general circulation models (GCMs). The results show that (1) the trend of temperature in July is associated with the first EOF pattern of the two combined fields, not with the EOF pattern of the regional warming; (2) although HadCM3 and ECHAM5 have simulated a false long-term trend of temperature, the statistical downscaling method is able to well reproduce a correct long-term trend of temperature in northern China due to the successful simulation of the trend of main PCs of the GCM predictors; (3) when the two-field combination and the projected EOF analysis are used, temperature change scenarios have a similar seasonal variation to the observed one; and (4) compared with the results of the common EOF analysis, those of the projected EOF analysis have been much more strongly determined by the observed large-scale atmospheric circulation patterns.     

1985-2005年东海海表温度时空变化特征分析

利用1985-2005年间AVHRR辐射计获取的东海海表温度资料,研究其时空变化特征.1985-2005年间东海海表平均温度总体呈上升趋势.对东海海温距平(SSTA)进行经验正交函数(EOF)分解,得到其2个主要变化模态,EOF1占总方差变化的34.8％,主要变化周期为3～5 a,表示1985-2005年中东海绝大部分...     

利用多时次资料的EOF迭代温度长期预报

考虑多时次历史资料，基于ＥＯＦ迭代方案，将观测事实与统计方法结合，建立预报因子与预报对象的联系，开展长期预报试验。对四川盆地夏季温度的预报表明：这种容纳多时次资料、基于ＥＯＦ迭代的物理－统计预报方法是一种有效的长期预报途径。     

河南省和中国夏季降水类型差异分析

利用河南省1951－1999年38个站点的降水资料，分析了河南省夏季降水距平百分率空间分布，并用EOF对雨量进行分解，同时归类合成，给出了河南省的6种雨型，在此基础上，对比分析了中国雨型和河南省雨型之间的差异。     

Retrieval of vertical wind profiles during monsoon from satellite observed winds over the Indian ocean using complex EOF analysis

The aim of this paper is to study the feasibility of deriving vertical wind profiles from current satellite observations. With this aim, we carried out complex empirical orthogonal function (CEOF) analysis of a large number of radiosonde observations of wind profiles over the Indian Ocean during the monsoon months. It has been found that the first two CEOFs explain 67% of the total variance in wind fields. While the first principal component is well correlated with the winds at 850 mb (r = 0:80), the second one is highly correlated with winds at 200 mb (r = 0:89). This analysis formed the basis of a retrieval algorithm which ensures the retrieval of vertical profiles of winds using satellite tracked cloud motion vector winds. Under the assumption that accurate measurements of wind are available at the above mentioned levels, the r.m.s. error of retrieval of each component of wind is estimated to range between 2 ms^-1 and 6 ms^-1 at different levels, which is much less than the natural variance of winds at these levels. For a better visualization of retrieval, we have provided retrieved and true wind profiles side by side for four typical synoptic conditions during the monsoon season.     

基于EOF和小波分析的福建近四十年旱涝时空变化特征研究

采用经验正交函数分解(EOF)、快速富里叶变换(FFT)、连续 (CWT)和正交小波变换(OWT),对近41 a来福建省25个代表站不同雨季旱涝指数(Z指数)序列进行了分析.结果表明:(1) 福建旱涝在1965-1975及1990年代具有显著的2-3 a周期;(2) 在1980年代中期以后南北反向变化具有显著的1 a和3-4 a周期;(3) 中西部与其它区域的反向变化,在1985-1998年间有显著的1-2 a周期,在1980年代以后9-13 a周期较强;(4) 近40年来有干旱趋势,南部(东部)比北部(西部)明显,其中1990年代这种趋势显著.(5) 1960年代和1980年代相对湿润,而1970年代和1990年代则相对干旱.     

白银市6-8月降水气候预测的均生函数场模型

对白银市4个代表站1957～1996年6～8月的降水量场进行经验正交函数(EOF)分解，得到方差贡献最大的第一特征向量，对第一特征向量的主分量建立均生函数模型并外推5年预报，用预报出的时间系数乘以相应的特征向量得到6～8月降水量场的预报值。