Seasonal and Interannual Variations of Upper Tropospheric Water Vapor Band Brightness Temperature over the Global Monsoon Regions

ＳｅａｓｏｎａｌａｎｄＩｎｔｅｒａｎｎｕａｌＶａｒｉａｔｉｏｎｓｏｆＵｐｐｅｒＴｒｏｐｏｓｐｈｅｒｉｃＷａｔｅｒＶａｐｏｒＢａｎｄＢｒｉｇｈｔｎｅｓＴｅｍｐｅｒａｔｕｒｅｏｖｅｒｔｈｅＧｌｏｂａｌＭｏｎｓｏｏｎＲｅｇｉｏｎｓ①ＱｉａｎＷｅｉｈｏｎｇ（...     

副热带高空急流各中心强度时间变化及分析

利用NCEP再分析资料,分析了中纬度地区的副热带高空急流各中心200 hPa上的强度的季节、年际和年代际的变化.结果表明,高空急流各中心位置的季节变化形态不一致,表征强度的各特征参数的季节特征虽都呈现冬强夏弱的主要特征,各中心的变化特点在于:东亚中心的急流面积和风速都有较大的变化;非洲中心面积变化小,但风速变化较大;而北美中心急流面积变化较大,风速变化较小.也有各自不同的变化形态和季节转换特征,四季的各急流中心的变化均不一致.急流各不同中心的各季节的强度特征参数发生年际和年代际变化的时期虽不尽相同,但大致都存在6~8 a的振荡周期.     

全球变暖趋缓背景下辽宁夏季降水变化及水汽输送特征

利用中国气象数据网提供的中国地面气候资料日值数据集(V3.0)中的降水数据以及ERA-Interim逐月再分析资料对全球变暖趋缓背景下(1998年后)辽宁夏季降水变化特征及水汽输送对其的影响进行研究.结果表明:全球增暖减缓背景下,辽宁夏季降水量存在一定的增加趋势,但趋势较弱,其中辽宁南部降水的增加趋势较其他地区显著,对...     

An OGCM Simulation of Seasonal and Interannual Variabilities in the Surface—Layer Pacific of the Equatorial Band

The heat budget is analyzed in the surface-layer (0-50 m) Pacific of the equatorial band (10°S-10°N),using the simulation of an ocean general circulation model from 1945 to 1993. The analysis indicates that downward net surface heat flux from the atmosphere and ocean advective heat fluxes play distinct roles in seasonal and interannual variabilities of surface-layer ocean temperature. The surface heat flux dominantly determines the ocean temperature in the seasonal time-scale. But, it has a negative feedback to the ocean temperature in the interannual time-scale. The interannual variability of ocean temperature is largely associated with the cold advection from off-equatorial divergent flow in the central Pacific and from upwelling in the cold tongue. Both the surface heat flux and ocean advective heat fluxes are important to the ocean temperature during an El Nino event. The ocean advective heat fluxes are further associated with local westward trade wind in the central Pacific. These results are largely consistent with some regional observational analyses.     

西北太平洋季风槽的季节和年际变化特征及其与热带气旋生成大尺度环境因子的联系

利用ERA-Interim再分析资料分析了夏秋季西北太平洋季风槽的气候特征以及季节和年际变化特征及其对西北太平洋热带气旋和台风(TCs)生成大尺度环境因子的影响。研究结果表明了西北太平洋季风槽有很明显的季节变化,在6~7月,季风槽和强对流活动区在5°N~15°N的南海和西北太平洋西侧上空,并逐渐东伸;到了8~9月,季风槽和强对流活动区向北移动、并向东扩展,一般位于10°N~20°N的南海和西北太平洋西侧、中部上空,有的年份可东伸到西北太平洋东侧,强度加强;到了10~11月,季风槽迅速减弱,并成为涡旋,强对流活动区也向南移和向西收缩。同时,研究还表明了西北太平洋季风槽有明显的年际变化。在季风槽强的年份,季风槽和强对流活动区可以从南海经西北太平洋西侧和中部东伸到西北太平洋的东侧上空;而在季风槽弱的年份,季风槽和强对流活动区主要位于南海和西北太平洋西侧和中部上空,季风槽强度的年际变化对它的季节变化也有重要影响。此外,研究还表明了随着季风槽的季节和年际变化,西北太平洋TCs生成的大尺度环境因子分布也发生很明显的变化。     

An OGCM Simulation of Seasonal and Interannual Variabilities in the Surface-Layer Pacific of the Equatorial Band

l. IntroductionThe physical mechanisms contro1ling t]de El Nifio event have been studied based on ob-servations in the equatorial Pacific (Weare l983; Reed l986; Hayes et al. l99l; McPhadenand Picaut l990; Frankignoul et al. 1996; Weisberg and Wang l997). One of the most impor-tant issues is whether the surface heat flux ojr ocean advective heat fluxes are dominant in con-trolling the sea surface temperature (SST). Some studies indicated that the SST is mainly con-trolled by the surface…     

Climatology and Interannual Variability of the Southeast Asian Summer Monsoon

ＣｌｉｍａｔｏｌｏｇｙａｎｄＩｎｔｅｒａｎｎｕａｌＶａｒｉａｂｉｌｉｔｙｏｆｔｈｅＳｏｕｔｈｅａｓｔＡｓｉａｎＳｕｍｍｅｒＭｏｎｓｏｏｎＫ．－Ｍ．ＬａｕＬａｂｏｒａｔｏｒｙｆｏｒＡｔｍｏｓｐｈｅｒｅｓ，Ｃｏｄｅ９１３，ＮＡＳＡ－ＧｏｄｄａｒｄＳｐａｃ...     

Characteristics of the Mean Water Vapor Transport over Monsoon Asia

ＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅＭｅａｎＷａｔｅｒＶａｐｏｒＴｒａｎｓｐｏｒｔｏｖｅｒＭｏｎｓｏｏｎＡｓｉａＹｉＬａｎ（伊兰）（ＩｎｓｈｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙｓｉｃｓ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｂｅｉ...     

Model Study on the Interannual Variability of Asian Winter Monsoon and Its Influence

ＭｏｄｅｌＳｔｕｄｙｏｎｔｈｅＩｎｔｅｒａｎｎｕａｌＶａｒｉａｂｉｌｉｔｙｏｆＡｓｉａｎＷｉｎｔｅｒＭｏｎｓｏｏｎａｎｄＩｔｓＩｎｆｌｕｅｎｃｅＪｉＬｉｒｅｎ（纪立人），ＳｕｎＳｈｕｑｉｎｇ（孙淑清）ＩｎｓｔｉｔｕｔｅｏｆＡｔｍｏｓｐｈｅｒｉｃＰｈｙ...     

Retrieval of Upper Tropospheric Relative Humidity by the GMS-5 Water Vapor Channel： A Study of the Technique

This paper presents an analysis of a technique for retrieving upper tropospheric relative humidity through the GMS-5 satellite‘s 6.7-micron water vapor channel brightness temperature. NCEP analysis shows that a critical assumption of the retrieval theory, namely the constant temperature lapse rate,matches only in the tropical atmosphere. By statistical analyses of brightness temperature simulated by a radiative transfer model and of relative humidity, we examine the effect of lapse rate on this retrieval method and obtain retrieval parameters and error estimates applicable to the GMS-5 satellite over East Asia. If the retrieval parameters are properly chosen, the relative error of retrieving the upper tropospheric relative humidity in this region is less than 10%, and if applied to the low-latitude summer atmosphere, it is less than 5%.     

地基GPS遥感西藏改则站大气可降水量变化特征及其与夏季降水的关系

利用中日JICA项目2010-2011年期间的地基GPS探测逐时大气可降水量（PWV）资料,分析了西藏西部改则站PWV的季节变化和日变化特征及其与夏季降水的关系。结果表明：（1）该站PWV存在明显的季节变化特征,其高（低）值出现在6-9（12-3）月,呈现出明显的单峰型变化特征,同时表现出春季持续上升和秋季快速下降的特点。（2）谐波分析表明,改则站各季PWV日变化均以日循环为主,只是夏季也表现出一定的半日循环特征。（3）改则站PWV存在明显的日变化特征,低值一般出现在当地时间的凌晨至次日上午,各季谷值普遍出现在当地时间10：00前后;高值通常出现在当地的午后至午夜,但各季最大值出现时间不固定;（4）改则站降水通常都发生在PWV高值期,降水发生前后PWV有明显的逐渐积累与迅速下降的变化特征,PWV达到峰值的时间提前于降水。PWV对累积降水频次的影响要比累积降水量更显著。     

伴随韩国雨季开始和结束早晚的关联场分析

分析了与韩国雨季开始和结束的年际变化相关联的一些要素场发生的变化。分别对雨季开始和结束早晚的个例进行了合成分析。６月月平均资料用来分析与雨季开始早晚相关联的要素场变化，而在分析与雨季结束早晚相关联的要素场变化时则利用７月月平均资料。结果表明，对应雨季开始（或结束）早晚，大气环流和表面温度等要素不仅在东亚地区、而且在远离东亚的地方具有显著的差异。在东亚地区的显著差异主要是高空急流和西太平佯副热带高压。远离东亚的显著差异主要是印度季风和ＥＮＳＯ现象。印度季风与韩国雨季开始和结束均有关联，但ＥＮＳＯ现象只与雨季开始显著相关、而与结束并没有显著的关联。     

Interannual and Interdecadal Variations in Heat Content of the Upper Ocean of the South China Sea

The vertically averaged temperature (TAV) from surface to 100 m depth of the South China Sea for the period 1959-1988 is analyzed. The results indicate that there is a significant long-term variability from interannual to interdecadal scales in the heat content in the upper ocean. The heat content of the upper ocean of the South China Sea increases evidently in the El Nino year. TAV anomaly in the ocean was negative from the end of 1950’s to early l970’s, and then changed to positive. The changes of TAV of the ocean are closely related to ENSO events, the Asian winter monsoon and the tropical atmospheric circulation anomalies.     

The interannual variability of East Asian Winter Monsoon and its relation to the summer monsoon

1.IntroductionOvertheEastAsiaregion,themostprominentsurfacefeatureofthewintermonsoonisstrongnortheasterliesalongtheeastflankoftheSiberianhighandthecoastofEastAsia.At500hPathereisabroadtroughcenteredaboutatthelongitudesofJapan.Thedominantfea-tureat2O0hPaistheEastAsianjetwithitsmaximumlocatedatjustsoutheastofJapan.Thisktisassociatedwithintensebaroclinicity,largeverticalwindshearandstrongadvectionofcoldair(StaffmembersofAcademiaSinica,l957,LauandChang,1987;BoyleandChen,1987;Chenetal.,1991…     

中国东部夏季水汽输送的年代际变化特征

基于1948—2012年NCEP/NCAR月平均再分析资料,采用9 a滑动平均、EOF分析及合成分析方法,研究了我国东部夏季水汽输送的年代际变化特征。结果表明:6—8月水汽输送由强转弱发生在1975年前后,水汽输送异常显著区域主要位于东部地区;6月南海到我国东部地区的水汽输送存在年代际变化,7月孟加拉湾、南海和西太平洋(8月印度洋、南海和西太平洋)到我国东部的水汽输送同样存在年代际变化;6—8月年代际变化前后水汽输送矢量分布与相应月份水汽输送通量年代际特征向量场的空间分布基本一致;显著的水汽通量散度辐合区位于华中以西经华北到东北地区,长江以北水汽辐合(辐散)异常显著区域由风场的辐合(辐散)异常和水汽平流异常共同造成,长江以南地区水汽辐合(辐散)异常显著区域主要由风场的辐合(辐散)异常造成。     

东亚太平洋地区近地面臭氧的季节和年际变化特征及其与东亚季风的关系

利用东亚清洁背景站近地面臭氧观测资料,结合风场和降水资料,分析东亚各地区臭氧的多年季节变化特征,并探讨东亚太平洋地区臭氧的季节和年际变化与季风的关系以及影响近地层臭氧的主要因子。结果表明：东亚大部分地区与北半球背景站观测一致,近地层臭氧季节变化表现为春季最高、夏季最低的特征;但在东亚中纬度33～43°N,臭氧表现为夏季最高,而在东亚20°N以南地区臭氧则表现为冬末、春初最高。东亚太平洋沿岸近地面臭氧的季节变化主要受东亚冬、夏季风环流的季节变化控制。该地区不同纬度上春季峰值出现时间的差异与亚洲大陆春季不同时期污染物输送路径的差异有关。对东亚太平洋沿岸对流层顶附近位势涡度、高空急流和垂直环流季节变化的分析表明,冬春季可能是平流层向对流层输送的最强期,对近地面臭氧贡献最大。初夏至秋季（5-11月）,平流层向对流层输送较弱,对近地面臭氧贡献较小。东亚太平洋地区夏季风爆发的时间和强度以及季风环流型的年际差异是导致该地区春、夏季臭氧年际变化的主要原因;而季风降水和云带位置以及平流层一对流层交换是造成臭氧年际变化的其他原因。     

CRA40在中国地区GNSS水汽反演中的适用性评估与分析

基于中国气象局发布的CRA40气象再分析资料,计算地基GNSS水汽反演中涉及气压、气温、大气水汽加权平均温度（T_m）、天顶对流层总延迟（ZTD）等关键参数,并分别以地面气象站（气压、气温）、无线电探空测站（T_m）以及地基GNSS测站（ZTD）为参考,对这些参数在中国地区的精度和可靠性开展了系统的评估.计算结果与欧洲中期天气预报中心（ECWMF）最新一代ERA5产品的计算结果进行比较,结果表明：基于CRA40计算的测站处气压和ZTD的平均RMS（均方根）分别为0.91 hPa和13.5 mm,略差于ERA5;计算的测站处气温和T_m平均RMS分别为2.67 K和1.47 K,略优于ERA5.三类参数（气压、气温、ZTD）的日变化总体趋势与实际观测符合较好.     

基于再分析资料的西南区域近50 a空中水资源的气候特征

利用1961—2012 年NCEP/ NCAR 的再分析月平均资料,分析了中国西南区域(四川、重庆、云南、贵州、广西大部分地区、西藏东部)水汽总量和水汽输送的气候特征。结果表明：西南区域水汽总量近50 a 来呈整体减少趋势;水汽含量在850—700 hPa 之间最为丰富;西南区域东湿西干,重庆、贵州、广西、四川东部水汽总量相对丰富;影响西南区域全年水汽量的有四个输送通道,春季水汽主要来源于孟加拉湾和偏西气流,夏季主要受到孟加拉湾和印度洋季风影响,秋季水汽主要来源于西太平洋,冬季则主要来源于偏西风和西太平洋;西南区域全年主要为水汽汇合区（除云南大部分地区以外）,常年有两个水汽辐合中心,一个在西藏与四川交接处（青藏高原东南侧）,一个在贵州及其附近地区;而云南上空主要为水汽辐散,仅夏季部分地区为水汽汇合区。     

Seasonal variations in the vertical structure of water vapor optical depth in the lower troposphere over a tropical station

Spatio-temporal variations of water vapor optical depth in the lower troposphere (450-3850 m) over Punt (18o32’N, 73o51’E, 559 m Above Mean Sea Level), India have been studied over a period of five years. The mean ver-tical structure showed that the moisture content is greatest at the lowest level and decreases with increasing altitude, except in the south-west monsoon season (June to September) where an increase upto 950 m has been found. Optical depths are maximum in the monsoon season. The increase from pre-monsoon (March-May) to monsoon season in moisture content on an average is by about 58% in the above altitude range. The temporal variations in surface Rela-tive Humidity and optical depth at 450 m show positive correlation. The amplitude of seasonal oscillation is the larg-est at 1465 m altitude. The time-height cross-sections of water vapor optical depths in the lower troposphere showed a contrast between years of good and bad monsoon.     

Seasonal Variations in the Vertical Structure of Water Vapor Optical Depth in the Lower Troposphere over a Tropical Station

Spatio-temporal variations of water vapor optical depth in the lower troposphere (450-3850 m) over Pune (18o32’N, 73o51’E, 559 m Above Mean Sea Level), India have been studied over a period of five years. The mean ver-tical structure showed that the moisture content is greatest at the lowest level and decreases with increasing altitude, except in the south-west monsoon season (June to September) when an increase upto 950 m has been found. Optical depths are maximum in the monsoon season. The increase from pre-monsoon (March-May) to monsoon season in moisture content on an average is by about 58% in the above altitude range. The temporal variations in surface Rela-tive Humidity and optical depth at 450 m show positive correlation. The amplitude of seasonal oscillation is the larg-est at 1465 m altitude. The time-height cross-sections of water vapor optical depths in the lower troposphere showed a contrast between years of good and bad monsoon.