琼州海峡海面风场特征的观测分析

在检验资料可靠性的基础上，利用船载自动站、浮标站与岸基自动站测风资料分析了琼州海峡海面风速空间变化规律，以及秋冬季节的海面风场的日变化特征。结果表明：(1) 琼州海峡海面风速平均比沿岸风速大3～4 m/s，当沿岸风速≥8.0 m/s(5级)时，海面风速比沿岸大5～6 m/s；(2) 海峡海面阵风系数随着风速加大而减小。沿岸风速<5级时，海面平均阵风系数在1.4～1.5之间，风速≥5级时，平均阵风系数为1.35左右；(3) 秋冬季节，海面的平均风速日较差与风一致率均小于沿岸，当海面出现≥10.8 m/s(6级)强风时，海面与沿岸的风速日较差减小，风一致率增加。     

南海近海面风场变化特征及其与ENSO的相关性研究

利用1979—2017年共39 a欧洲中期天气预报中心（ECMWF）海表面10 m风场资料,采用经验正交函数方法（EOF）、小波时频特征分析等方法分析了南海近海面风场变化特征及其对ENSO的响应。结果表明：南海近海面风场第一模态海表面平均风速呈减小趋势, 呈现年代际变化,且与ENSO相关,但相关性在1990年后趋于减小;第二模态中南海北部和南部平均风速呈减小趋势,中部增大;第三模态中南海中部海表面平均风速趋于减小,北部和南部增大,第二和第三模态均表现为年际变化,且均与ENSO显著相关,近年来ENSO与第三模态的相关性逐渐增强。春季南海表面平均风速从南到北逐渐增加;夏季在越南沿岸部分海域仍有一个风速极大值中心,从该海域向四周逐渐减小,整片海域风向均是西南风;秋季由南向北依次增加;冬季南海整片海域风速都较大,越南沿岸和我国东沙群岛海域存在两个极大值中心。     

近10年我国用水与水资源利用情况时空特征研究

水资源是社会经济发展的重要物质基础,地下水是水资源的重要组成部分,水资源合理开发利用是社会经济可持续发展的重要因素之一.基于《中国统计年鉴》及《中国水资源公报》中2003—2012年用水及供水相关数据,利用EOF展开方法,分析了我国31个省级行政分区用水和水资源利用情况的空间分布及时间演变特征.研究结果表明:全国总用水量不断增加,但增幅有所减小,各地区用水总量变化趋势多样,中东部变化较大,西部变化较小,河北省、浙江省、海南省、青海省和甘肃省与其他地区反相变化;江苏省、浙江省和广东省地下水资源的利用与工业产业协调发展,可作为其他地区的典范;北京市、天津市、河北省、山西省、陕西省、甘肃省和青海省通过调整产业结构,地下水资源利用状况向良好的趋势发展;新疆维吾尔自治区和内蒙古自治区的地下水资源利用现状和趋势不容乐观,应注意增强环保意识,调整产业结构,以求水资源得到协调、可持续的开发和利用.     

基于MODIS数据的近10年宜昌城市热岛效应时空变化特征

利用2010-2019年宜昌研究区2、5、8月和11月晴空天气的MODIS地表温度产品,结合GIS技术,分析热岛效应昼夜、季节和年际变化特征.结果表明:(1)热岛空间分布受地形地貌影响较大,热岛区主要分布在主城区至东南部平原地带;(2)热岛区和冷岛区面积白天均多于夜间,热岛强度白天强于夜间;(3)夏季热岛区面积达到最大...     

2009年11月汕尾红海湾海面风场的观测分析

广州亚运会帆船帆板的比赛项目于2010年11月在汕尾红海湾广东省水上运动基地举行。根据2009年11月海上浮标观测数据,分析了红海湾赛场的海面风场特征及日变化规律;并根据地面气压场特点和风场日变化特征对海面风场进行了分类;最后,结合海-陆气压差观测数据,初步探讨海陆热力差异与海面风日变化的关系。结果表明:11月红海湾赛场以偏北和偏东风为主,风向具有近似余弦函数的日变化特征;风速的日变化不明显,但午后14—18时弱风和强风的出现机会较少,最适合比赛。11月红海湾赛场的海面风可归纳为海陆型、系统转折型和阴天型三种类型,三种类型的海面风分别占月总日数的46.7%、33.3%和20%。浮标-海丰观测站的气压差与海面风南北分量的变化有密切关系,可作为海面风场的有效预报指标。     

一种新的台风海面风场的拟合方法

基于台风风场的经验风公式和修正的梯度风方程并考虑了台风气压场的非对称性,提出了一种新型的台风风场合成模式。经过对10多个不同类型热带气旋(台风)的检验,结果表明,新的模式可以模拟出各种强度及不同眼半径台风的海面风场,比以往常用模式能更真实地反映实际台风风场。     

基于EOF和小波分析的福建近40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41a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年及1990年代具有显著的2-3a周期；（2）在1980年代中期以后南北反向变化具有显著的1a和3-4a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1-2a周期，在1980年代以后9-13a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。     

近51年我国对流层顶高度的变化特征

利用NCEP/NCAR的对流层顶气压多年月平均和逐月平均再分析资料,运用EOF和REOF方法对近51年中国对流层顶高度的空间分布和时间演变特征进行了详细分析。结果表明,中国地区热带对流层顶(第二对流层顶)和极地对流层顶(第一对流层顶)的边界线,2月最南,8月最北,较高的热带对流层顶从2月开始,逐渐北进,8月到达最北界(44°N附近),然后开始南退,2月其北界处于最南端,在29°～30°N附近;我国29°～44°N之间的中纬度地区,对流层顶高度的年变化幅度较大;对流层顶高度场有三种主要的模态:第一种为全区一致的偏高(偏低)型;第二种为南高(低)北低(高)的南北相反分布型;第三种为南北地区-中部地区相反分布型。对对流层顶高度场进行REOF分解可将中国地区分为6个气候分区,即华南区、新疆区、东北区、华北区、长江流域区和青藏高原区,各区对流层顶高度最大值一般都出现在夏季,最小值出现在冬季,只有华南区的最大值出现在春季,最小值出现在夏季。中国地区对流层顶高度的年际变化和长期趋势具有十分明显的区域性。     

一种台风海面非对称风场的构造方法

针对台风数值预报中由于采用对称模型而导致预报误差的现实，通过引入非对称分布的台风最大风速、最大风速半径等因子，在得到台风报告中7级风和10级风的半径的基础上，利用最佳权系数方案来得到非对称的台风外围风速分布因子，从而对Chan and Williams 1987年提出的切向风廓线方案进行改造，进而得到了台风海面非对称风场的计算式。检验表明，该方法能够描述台风海面风场的非对称分布，具有较好的应用前景。     

浙北沿岸海域海面风场反演方法的研究

高质量的海面实况风场是海洋气象监测和预报的基础,卫星反演的大陆沿岸海域海面风场的准确率不高。文章基于反映近地面风速廓线变化的指数律公式,利用浙江北部沿岸海岛或滩涂上布设的中尺度自动站来反演附近海面风场,并使用客观分析方法将反演的离散风场值转换到中尺度网格上,从而获得完整的高分辨率海面风场。指数律中参数α值对于反演风场的准确率至关重要,它主要受到下垫面状况以及大气层结状态的影响,而后者的影响较前者更大。文章使用多个风塔站的风廓线率值进行了反演风场的误差试验,结果表明:目前单一风速廓线还无法取得最优的反演效果,有必要分季节使用多站风速廓线。使用混合风速廓线得到的总体样本的平均偏差为0.04 m·s~(-1),平均绝对误差为1.51 m·s~(-1),均方根误差为2.01 m·s~(-1)。对海面反演风场的优化可以将总体样本的平均绝对误差和均方根误差分别降低到1.28和1.68 m·s~(-1)。     

OBSERVATION AND ANALYSIS OF SEA SURFACE WIND OVER THE QIONGZHOU STRAIT

The spatial variation and diurnal fluctuation of sea surface wind over the Qiongzhou Strait were described using verified datasets from automatic weather stations on board a ferry, buoys, and on the coast. Results are as follows: (1) On average, sea surface wind speed is 3–4 m/s larger over the Qiongzhou Strait than in the coastal area. Sea surface wind speeds of 8.0 m/s or above (on Beaufort scale five) in the coastal area are associated with speeds 5–6 m/s greater over the surface of the Qiongzhou Strait. (2) Gust coefficients for the Qiongzhou Strait decrease along with increasing wind speeds. When coastal wind speed is less than scale five, the average gust coefficient over the sea surface is between 1.4 and 1.5; when wind speed is equal to scale five or above, the average gust coefficient is about 1.35. (3) In autumn and winter, the diurnal differences of average wind speed and wind consistency over the strait are less than those in the coastal area; when wind speed is 10.8 m/s (scale six) or above, the diurnal difference of average wind speed decreases while wind consistency increases for both the strait and the coast.     

THE TEMPORAL AND SPATIAL DISTRIBUTION OF SEA SURFACE WIND ALONG THE COAST OF GUANGDONG PROVINCE IN CHINA

Temporal and spatial distribution characteristics of sea surface wind in Guangdong''s coastal areas were analyzed with data from four offshore observational stations between 2012 and 2015. The results are shown as follows: (1) The probability distribution of wind speed was basically consistent with Gaussian distribution characteristics; winds of Beaufort force 6 or higher were observed mainly in far offshore stations from October to March. (2) The probability distribution of wind direction was represented well by Weibull distribution. The deviation of wind direction of far station was relatively small for it was mainly controlled by monsoon over the South China Sea, while the near offshore station had a relatively large diurnal variation because of the influence of local synoptic systems such as sea-land breeze. (3) There were significant seasonal differences in wind speed and direction observed by different offshore observational stations. In strong wind seasons, the deviation of wind direction was relatively small while the deviation of wind speed was relatively large, and vice versa. In contrast with Class I station, the other three stations exhibited approximately normal distribution of wind direction and wind speed deviations. (4) Wind direction diurnal variation was moderate in windy periods, while it was obvious in relatively lower speed conditions. The deviation of wind speed in windy periods was generally greater because it was influenced by mesoscale weather systems for 10-20 h, and the influence was complicated, resulting in greater local differences in wind speed.     

1981—2020年安徽省不同重现期最大风速和极大风速时空变化特征

分别从质量控制级别、有效数据完整率、是否均一等方面考虑,选取安徽省51个气象站1981—2020年逐日10 min最大风速和2006—2020年逐日极大风速资料,基于最大风速资料应用阵风系数法构建1981—2005年极大风速,得到1981—2020年极大风速的长时间序列数据;对风速资料进行拟合适度检验,估算了安徽省不同重现期最大风速和极大风速的时间变化以及空间分布,并对极大风速序列延长前后重现期估算情况进行了对比。结果表明：(1)利用阵风系数法构建的极大风速数据可信,可为因缺少长时间序列的极大风速观测而无法进行50年或者更长重现期估算提供参考;(2) 1981—2020年安徽省历年最大风速强度为12.38 m/s,极大风速强度为20.55 m/s,均为皖南低矮山区的风速值较低,沿江西部及江淮之间中部处于相对大值区;(3) 30年重现期最大风速为12.09～27.23 m/s,50年为12.64～29.01 m/s,均是石台站最小,桐城站最大;30年重现期的极大风速为23.51～39.56 m/s,50年为24.58～41.93 m/s,均为池州站最小,桐城站最大;(4)短期的观测资料会...     

MICROSTRUCTURES AND TEMPORAL VARIATION CHARACTERISTICS DURING A SEA FOG EVENT ALONG THE WEST COAST OF THE TAIWAN STRAIT

Synoptic systems and microphysical properties associated with a sea fog event are analyzed based on the measurements of visibility, meteorological elements and fog droplet spectrum from a comprehensive field campaign in Xiamen, Fujian province during spring 2013. The influences of meteorological elements on the microstructures of the sea fog are also discussed. The results showed that the wind speed and direction changed suddenly during the intermittent and disperse phases of the sea fog. Liquid water content, number concentration and average diameter varied obviously in the development, mature and disperse phases of the sea fog. The burst re-enforcement of sea fog was accompanied by explosive broadening of fog droplet spectrum; average diameter, number concentration and liquid water content increased sharply; and background meteorological conditions also changed significantly. The microstructures fluctuated intensely due to changes in turbulence, radiation and meteorological conditions at different stages, including nucleation, condensation, coagulation, and evaporation, as well as the discontinuity of spatial distribution of droplets.     

热带海表温度和低层风场的年际变率及与ENSO循环的相关特征研究

采用 NCEP/NCAR的 1 979～ 1 998年逐月平均的海表温度及 1 0 0 0 h Pa风场资料 ,进行滤波和均方差计算 ,得到了热带太平洋、印度洋、大西洋海表温度 (SST)和风场的年际变化特征。用旋转主分量 (RPC)方法和投影法对热带三大洋海表温度距平 (SSTA)进行分析 ,得到了各大洋 SSTA演变的主要时空特征和相应的距平风场特征 ;并用相关分析研究热带三大洋与ENSO相关的特征 ,得到三大洋间的同期相关关系为 :印度洋 SSTA与赤道东太平洋 SSTA成正相关 ,而赤道东大西洋 SSTA与赤道东太平洋 SSTA成弱的负相关 ;赤道印度洋在落后于赤道东太平洋 3个月左右时正相关达到最大 ,赤道大西洋在超前于赤道东太平洋 6个月左右时负相关达到最大 ;热带印度洋和大西洋与 ENSO相关的分量对各自大洋海表温度年际变化的方差贡献数值相近 ,最大在 40 %以上 ,平均解释方差分别为 1 4%和 1 2 %。     

南北极海冰的时空变化特征

本文分析了南北极海冰多年平均覆盖资料，给出南北极海冰的年内变化特征，极地海冰最多最少月份的空间分布。计算了２月及９月海冰年际变化方差分布，并对２月及９月南北极海冰７个分区域覆盖面积作了ＥＯＦ分解，为进行南北极海冰影响全球气候的数值试验提供了海冰变化的空间配置     

ANTARCTIC SEA ICE AND THE POLAR VORTEX INDEX:TEMPORAL AND SPATIAL CHARACTERISTICS AND THEIR RELATIONSHIP

The cluster analysis method has been used to divide the Antarctic sea ice variation field into 5 sectors.Then,foreach of these sectors,the corresponding indexes of vortex area and vortex intensity on the 500 hPa level have been calcu-lated.These data were used to analyse the temporal and spatial characteristics of both Antarctic sea ice and the vortexindex variations and their relationship.Our results show that substantial differences are presented in the climatic patternand interannual variations of the sea ice data and vortex index in different sectors.The maximum sea ice extent varia-tions appear in sector 1 and sector 4.Oscillation periods of 2—2.5 and 5—7 years exist in the variations of sea ice extentand vortex index in most sectors.A positive trend is only found in sector 1 sea ice extent while the other sectors shownegative trends.The average extent of the Antarctic sea ice as a whole has retreated at a rate of 1.6 latitudes per 100years.The vortex areas for all sectors have decreased.Nevertheless,the vortex intensities in 3 sectors have increased.Therelationship between sea ice and vortex characters in each sector is obvious,but a little complex.Sectors 1 and 5,whichare located in the Southeast Pacific and South Atlantic,are the most sensitive areas in terms of sea ice/atmosphereinteraction.     

BASIC CHARACTERISTICS OF SURFACE WIND. PRESSURE AND TEMPERATURE IN PLATEAU OF MONGOLIA

After analyzing the mean pressure, dominant wind and temperature data of 40 observation sta-tions in Mongolia from 1961 to 1990, we reach some conclusions as below: (a) The warm advec-tion in the free atmosphere hardly reaches the ground in the west in winter. Because of thermody-namic differences of various meso- and micro-topography, there are "multi-centers" in the pressurefield, and the dominant wind field is "disordered": the temperatures on the convexi-concave orog-raphy and sun-shady slope are different significantly. There is cold advection in the east side,which can reaches the ground and the air pressure field is a "unity". The wind field is dominated bythe west wind. The temperature differences of various slope directions are small, and becomesmaller with height. (b) In summer, the upper control flow (planetary west wind) becomes weak-er, and the orographic air pressure centers in the east develop. Over the windward side of themountain high pressure prevails, and over the lee side low pressure does. These areas becomedeserts for dryness and lack of rainfall. Air temperature in summer can be expressed by latitude,longitude and elevation.