热带印度洋和热带太平洋海温振荡规律的研究

选择1979-1993年间的热带气旋为试验个例，通过扰动热带气旋初始位置和初始结构。构造集合成员，用正压原始方程模式，进行路径集合预报试验，并初步探讨预报成员的集合方法。试验结果表明：热带气旋定位误差影响路径预报，但扰动初始位置的集合平均预报与控制试验的预报水平相接近。扰动热带气旋初始结构的集合预报试验表明，约有60％。70％个例的集合路径预报得到改进：此外，试验结果还表明，当环境引导气流较弱时，进行扰动热带气旋初始结构的集合预报，预报结果的改善较明显。     

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.     

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。     

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.     

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 %。     

STUDY ON THE MULTIVARIATE STATISTICAL ESTIMATION OF TROPICAL CYCLONE INTENSITY USING FY-3 MWRI BRIGHTNESS TEMPERATURE DATA

A technique for estimating tropical cyclone (TC) intensity over the Western North Pacific utilizing FY-3 Microwave Imager (MWRI) data is developed. As a first step, we investigated the relationship between the FY-3 MWRI brightness temperature (TB) parameters, which are computed in concentric circles or annuli of different radius in different MWRI frequencies, and the TC maximum wind speed (Vmax) from the TC best track data. We found that the parameters of lower frequency channels’ minimum TB, mean TB and ratio of pixels over the threshold TB with a radius of 1.0 or 1.5 degrees from the center give higher correlation. Then by applying principal components analysis (PCA) and multiple regression method, we established an estimation model and evaluated it using independent verification data, with the RMSE being 13 kt. The estimated Vmax is always stronger in the early stages of development, but slightly weaker toward the mature stage, and a reversal of positive and negative bias takes place with a boundary of around 70 kt. For the TC that has a larger error, we found that they are often with less organized and asymmetric cloud pattern, so the classification of TC cloud pattern will help improve the acuracy of the estimated TC intensity, and with the increase of statistical samples the accuracy of the estimated TC intensity will also be improved.     

影响我国热带气旋活动的气候特征及其与太平洋海温的关系

利用1956~2000年的热带气旋(简称TC,下同)资料对影响我国TC活动的气候特征进行了初步的统计分析,结果发现影响我国的TC活动具有明显的阶段性特征,1960年代影响我国的TC数明显偏少,而后进入偏多期,1990年代又相对偏少。影响我国的TC强度多集中于980~999 hPa,华东的闽、浙一带TC登陆比华南晚,但强度较大。在此基础上通过对影响我国的TC年个数与太平洋海温场进行相关分析,发现两个相关较密切的区域: 西太平洋暖池(120~150 E, 10~20 N)正相关区、赤道中东太平洋(180 ~90 W, 10 S~5 N)负相关区,这两个相关区具有较好的持续性。进一步分析影响我国的TC在El Ni駉年与La Ni馻年的气候特征发现,El Ni駉年影响我国的TC数较少,但强度较大,La Ni馻年则相反,影响我国TC多年和少年对应的太平洋海温距平分布形势分别与La Nia年和El Nio年的海温距平分布形势类似。     

A DIAGNOSIS OF THE INTERANNUAL VARIABILITY OF SEA SURFACE TEMPERATURE AND SURFACE WIND FIELD IN THE TROPICAL OCEANS AND ITS CORRELATIVE CHARACTERS WITH ENSO CYCLE

Utilizing the NCEP/NCAR reanalysis monthly datasets,and based on the filter and standarddeviation calculation,the interannual variability of sea surface temperature(SST)and 1000 hPawind field for the tropical Pacific,Indian and Atlantic Oceans is investigated for the past 20 years(1979—1998).The characters of space-time evolution in SST anomalies(SSTA)for each oceanand corresponding wind anomaly field are acquired by using rotated principal component(RPC)and linear regression analysis methods.Using the method of correlation analysis.the characters ofthree tropical oceans correlated with ENSO are investigated.The contemporary correlationbetween the SSTA in the Indian Ocean and in the equatorial eastern Pacific is positive,and there isa weak negative correlation between the SSTA in the equatorial east Atlantic Ocean and in theequatorial eastern Pacific.The lead-lag correlation analysis indicates that the SSTA in theequatorial Indian Ocean lags the dominant Pacific ENSO mode by 3 months,and the SSTA in theequatorial Atlantic Ocean leads ENSO mode by 6 months.The ENSO-correlated components intropical Indian Ocean and tropical Atlantic Ocean display much the same amount of total variance ineach ocean,i.e..14% in the Indian Ocean and 12% in the Atlantic Ocean and the maximums areall above 40%.     

RETRIEVAL OF CLEAR SKY MOISTURE PROFILES IN THE PACIFIC USING MEASUREMENTS OF MICROWAVE HUMIDITY SOUNDER FROM FY-3A SATELLITE

An improved Smith iterative method, which generally applies to microwave bands, is described. The moisture profiles retrieved from the brightness temperature data of microwave humidity sounder onboard FY-3A satellite, pertaining to clear sky, are shown over western North Pacific by using a vector-discrete ordination radiative transfer model. The retrieved profiles are compared with those from MODIS products, and the results of single point show that they are in good agreement with the results for lower layers. The distribution of retrieved humidity at 500 hPa is basically consistent with the actual situation, and the values are lower than that of the MODIS products. Compared with MODIS products, RMS is within 5.76g/kg at every single level separately.     

夏季西北太平洋热带气旋生成频次与热带海温关系的年代际变化

探讨了夏季(6—8月)西北太平洋(Western North Pacific,WNP)热带气旋生成频次(Tropical Cyclone Genesis Frequency,TCGF)与热带海温关系的年代际变化,发现影响WNP TCGF的热带海温型在1991/1992年发生了年代际变化。在1990年代初之前,TCGF正异常对应的热带海温异常(Sea Surface Temperature Anomaly,SSTA)呈现东部型La Ni?a衰减位相,前冬至春季WNP局地暖SSTA在其西北侧激发气旋异常,夏季时由热带印度洋冷SSTA继续维持。在1990年代初之后,TCGF正异常对应的热带SSTA呈现东部型La Ni?a向中部型El Ni?o快速转换的位相,夏季中太平洋暖SSTA在其西北侧激发气旋异常,同时热带东印度洋至海洋性大陆以及热带大西洋的冷SSTA通过垂直环流圈加强中太平洋的辐合上升运动,进一步维持其西北侧气旋异常。由于激发气旋异常的暖SSTA在第二个年代相较第一个年代明显偏南偏东,气旋异常和TCGF正异常在第二个年代也整体偏南且向东扩展至更远的区域。WNP TCGF与热带海温关系的年代际变化与1990年代初之后厄尔尼诺-南方涛动演变速率加快有关。      

热带西太平洋海表温度长期变化的特殊性

揭示了５０年代以来热带三大洋海表温度（ＳＳＴ）长期变化的两个基本构成（线性增温及Ｅｌ Ｎｉｎｏ－Ｌａ Ｎｉｎａ振荡）,并比较了它们在三大洋中的典型程度。在此基础上重点分析了热带太平洋西、中、东部ＳＳＴ长期变化的差异,指出热带西太平洋ＳＳＴ长期变化中Ｅｌ Ｎｉｎｏ－Ｌａ Ｎｉｎａ振荡相对较弱,线性增温趋势被年代际强弱振荡代替。     

POSSIBLE RELATIONSHIP BETWEEN THE INTERANNUAL ANOMALY OF THE TROPICAL PACIFIC SEA SURFACE HEIGHT AND SUMMER PRECIPITATION IN CHINA

By using NCEP GODAS monthly sea surface height(SSH) and 160-station monthly precipitation data in China,the seasonal and interannual characteristics of SSH are analyzed over the tropical Pacific,and correlations between SSH and summer rainfall are discussed.The results are shown as follows:(1) The tropical Pacific SSH takes on a "V" pattern in the climatic field with an eastward opening,and it is higher in the western part(in the northwestern part) than in the eastern part(in the southwestern part).The high-value areas are more stable in the northwest,and the value range(greater than 0.8 m) is larger in spring and summer than in autumn and winter.The high-value area in the southwestern part is the largest(smallest) and more northerly(southerly) in spring(summer).SSH is higher in spring and autumn than in summer and winter over the equatorial zone.(2) The interannual anomalies of the SSH are the strongest over the tropical western and southwestern Pacific and are stronger in winter and spring than in summer and autumn.The interannual anomalies are also strong over the equatorial middle and eastern Pacific.The distribution ranges are larger and the intensities are stronger in the autumn and winter.There is a close relationship between the SSH interannual anomalies and ENSO events in autumn,winter and spring.(3) When ENSO events take place in winter,according to the simultaneous relationship among the tropic Pacific SSH,850 hPa wind fields and the summer precipitation of China,it can be predicted that the precipitation will be significantly more than normal over the south of the Yangtze River,especially over Dongting Lake and Poyang Lake region,eastern Qinghai-Tibet Plateau,Yangtze-Huai River Valley,eastern part of Inner Mongolia and less than normal over the area of Great Band of Yellow River,North China and South China in successive summers.     

A DIAGNOSIS OF THE INTERANNUAL VARIABILITY OF SEA SURFACE TEMPERATURE AND SURFACE WIND FIELD IN THE TROPICAL OCEANS AND ITS CORRELATIVE CHARACTERS WITH ENSO CYCLE*

Utilizing the NCEP/NCAR reanalysis monthly datasets,and based on the filter and standard deviation calculation,the interannual variability of sea surface temperature (SST) and 1000 hPa wind field for the tropical Pacific,Indian and Atlantic Oceans is investigated for the past 20 years (1979-1998).The characters of space-time evolution in SST anomalies (SSTA) for each ocean and corresponding wind anomaly field are acquired by using rotated principal component (RPC) and linear regression analysis methods.Using the method of correlation analysis.the characters of three tropical oceans correlated with ENSO are investigated.The contemporary correlation between the SSTA in the Indian Ocean and in the equatorial eastern Pacific is positive,and there is a weak negative correlation between the SSTA in the equatorial east Atlantic Ocean and in the equatorial eastern Pacific.The lead-lag correlation analysis indicates that the SSTA in the equatorial Indian Ocean lags the dominant Pacific ENSO mode by 3 months,and the SSTA in the equatorial Atlantic Ocean leads ENSO mode by 6 months.The ENSO-correlated components in tropical Indian Ocean and tropical Atlantic Ocean display much the same amount of total variance in each ocean,i.e..14% in the Indian Ocean and 12% in the Atlantic Ocean and the maximums are all above 40%.     

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。     

近10年台湾海峡海面风场的时空特征变化动态分析

利用台湾海峡ASCAT海面风场数据和气象观测资料,通过EOF和统计方法综合分析台湾海峡海面风场2007—2017年10年的时空模态变化特征,使用Mann-Kendall法和滑动t-检验法对10年间海面风速进行突变检验,对台湾海峡海面风场季节变化时空特征进行分析研究。(1) “狭管效应”在台湾海峡海面风场上呈现明显的季节性特征,其中春季、秋季和冬季海面风场季节性特征显著,夏季表现不明显。受台湾岛地形和季风环流影响,台湾岛南北两端海面易出现风速增强的角流区,岛中央山脉背风区易出现低风速尾流区。(2) 10年间台湾海峡海面月平均风场EOF空间模态受台湾岛地形影响显著,台湾海峡海域为异常值偏差中心,易发生风速突然增幅和风向改变。时间模态大体表现为季节性振荡型变化,振幅在10年中表现为不活跃,呈逐年递减趋势。(3) Mann-Kendall法和滑动t-检验法等方法的突变检验结果表明风速并未发生显著性突变,10年间台湾海峡海面风速特征表现为从正相位向负相位的改变,且随着趋势持续加大,将可能发生风速突变。      

温度,盐度和风应力对南海海流模拟的影响

用美国普林斯顿大学海洋模式（ＰＯＭ）对南中国海的年平均海流进行了数值模拟,对温盐结构和风应力在海流形成中的作用进行了较详细的讨论。结果表明,仅有温盐水平不均匀分布也可以驱动海水而生成南海海流,但此种海流的结构较乱,最大流速只有３０～４０ｃｍ·ｓ－１。若温盐无水平结构,则在风应力驱动下,南海海流的结构较为有序,且最大流速可增至６０～７０ｃｍ·ｓ－１。在温盐水平分布不均匀并有风应力的作用时,生成的南海海流与仅有风应力作用时的海流场较相似,说明在南海海流的形成中,风应力的作用更为重要。海面自由高度的分析也证明了上述结论。     

NUMERICAL STUDY ON THE EFFECTS OF SEA SURFACE TEMPERATURE ON TROPICAL CYCLONE INTENSITY-PART I:NUMERICAL EXPERIMENT OF THE TROPICAL CYCLONE INTENSITY RELATED TO SST *

In the context of a model of tropical cyclone intensity based on an improved meso-scale atmospheric model, numerical simulation is performed of the track and intensity variation of tropical cyclones(TC) arising from sea surface temperature(SST) variation over a specified sea region. Evidence suggests that the model is capable of modeling quite welt the track and intensity of TC:SST variation leads to an abrupt change in the cyclone intensity:the response of the cyclone to the abrupt SST change lasts 8-12 h.     

光滑海面上风、温、湿廓线的层结订正模式及海气整体交换系数

详细介绍了光滑面标量粗糙度ＺＴ,Ｚｑ与风速粗糙度Ｚ０的相似表达式,论述了把Ｍｏｎｉｎ－Ｏｂｕｋｈｏｖ相似理论推广到光滑面上湍流气层的合理性,从而得到光滑面风、温、湿层结订正廓线与粗糙面廓线相统一的形式。总结了用该模式处理的三个海上梯度观测资料的计算结果,揭示出了微风时通过光滑海面的海气通量及整体交换系数受层结影响远大于风速影响的特征。并给出光滑界面上不同层结的整体交换系数随风速变化的拟合公式。     

NUMERICAL STUDY ON THE EFFECTS OF SEA SURFACE TEMPERATURE ON TROPICAL CYCLONE INTENSITY-PART I:NUMERICAL EXPERIMENT OF THE TROPICAL CYCLONE INTENSITY RELATED TO SST Duan Yihong;Qin Zenghao;Gu dianfeng;Li Yongping, Shanghai Typhoon Institute.Shangh

In the context of a model of tropical cyclone intensity based on an improved meso-scaleatmospheric model, numerical simulation is performed of the track and intensity variation oftropical cyclones (TC) arising from sea surface temperature (SST) variation over a specified searegion. Evidence suggests that the model is capable of modeling quite welt the track and intensityof TC: SST variation leads to an abrupt change in the cyclone intensity: the response of thecyclone to the abrupt SST change lasts 8—12 h.