有关OKJ波列研究及展望

文中对夏季特别是初夏时节频繁发生在欧亚地区的一种罗斯贝波列(OKJ)的系列研究进行了阶段性总结,分别阐述了OKJ波列的性质、影响范围以及在夏季波动中的地位.指出OKJ具有稳定的准定常波性质,相对较长的相干时间尺度,直接影响范围在欧亚,间接可波及北美,在夏季还可以和另一著名波列(P-J)产生相互作用,从而对东亚夏季的大气环流变化产生关键性作用,对气候预测也有指示意义.文中并提出当前存在的问题和需要进一步研究的方向.     

海洋性大陆区域OLR的气候低频振荡及其与中国降水的可能联系

利用1979—2009年NCEP/NCAR再分析资料和地面观测站降水资料,研究了海洋性大陆（Maritime Continent,MC）区域的低频振荡气候学特征及其与中国东部降水扰动的关系。结果表明:气候平均状况下MC区域存在显著的低频振荡（CLFO）,30～60 d季节内振荡在4—9月强度最大,且MC区域为低频OLR方差贡献率大值区。低频时间尺度上,MC区域OLR在4—9月有4次比较明显的活跃过程,在1～4（5～8）位相,对流相对较弱（活跃）。OLR的CLFO在热带地区显著东传,在南北方向亦存在位相的传播。从MC区域经南海、菲律宾群岛至中国长江流域存在类似于EAP波列（或P-J型遥相关）的扰动环流分布。不同位相上,低频环流及加热场的变化表明,中国降水的扰动在4—9月间受到MC区域CLFO的可能影响。低频热力场在南北方向上呈现EAP波列状或P-J型遥相关状分布。在OLR的CLFO的峰（谷）位相时,MC区域低层辐散（辐合）,高层辐合（辐散）,低频对流相对较弱（较强）,在MC区域至日本海激发EAP波列（或P-J型遥相关）;在对流层上层南亚高压因低频气旋（反气旋）而位置偏东（偏西）;中国的江南及河套地区降水偏少（偏多）,西南及青海、甘肃等地降水增加（减少）。在转换位相时,MC区域低频对流在部分地区更为活跃,在对流层低层激发低频的气旋-反气旋-气旋的波列,南亚高压偏南,长江中上游、吉林地区出现明显的辐合区,降水偏多,黄淮之间及云贵地区降水偏少。这些结果有助于人们深刻认识气候学意义上的低频振荡特征及LFO的季节锁相问题,有利于进一步认识中国不同地区降水扰动的成因。      

青藏高原地形对5、6月北半球环流影响数值模拟

利用NCAR CAM3.1模式进行了有无青藏高原地形的试验,通过两组试验结果的比较,研究了青藏高原地形对5、6月北半球500 hPa环流的影响。结论如下:春末夏初在北半球存在类似Rossby波列状的距平中心,5月波列产生于高原北侧的蒙古附近,途经鄂霍次克海、阿留申地区,到达北美西海岸;6月,由于西风急流北移、减弱及高原上空的非绝热加大,波列的产生地移至高原西北侧的巴尔喀什湖附近,强度减弱,造成该波下游的鄂霍次克海、勘察加半岛、阿拉斯加海域的强度相应减弱。另外,5月在鄂霍次克海和日本以东洋面附近的异常中心类似于负位相的OKJ波列,可以视为对正位相OKJ波列东段形成抑制作用;6月由于鄂霍次克海附近的负异常强度很弱,对OKJ波列东段的抑制作用很弱。     

江淮流域持续性暴雨过程前期的欧亚波列特征及其模拟研究

利用50余年的NCAR/NCEP再分析资料,对江淮流域持续性暴雨过程前期的环流特征进行了相关与合成分析。发现在过程前2—1周的对流层中高层西风带上,中西亚、中国东部沿海和白令海南侧相继有低压槽发展,呈现显著的罗斯贝波列信号特征。分析表明,正是该欧亚波列的东传和消失伴随的环流调整,导致了有利于持续性暴雨产生的稳定环流的形成。进一步采用区域数值模式检验了该波列特征对后期持续性暴雨的作用和影响过程,以1991年一次典型的江淮流域持续性暴雨过程为例,根据欧亚波列信号特征设计一组初始流场扰动,进行初值集合模拟试验。结果表明,过程强雨带及其环流背景的模拟对于初始场上欧亚波列信号区的扰动特征是相当敏感的,该初始扰动对模拟环流的后继影响,与持续性暴雨期间稳定环流特征的建立和维持确有密切关系。     

利用RegCM4.0模拟5-8月青藏高原异常加热的下游效应

利用区域气候模式,通过在青藏高原范围设置三种不同强度的大气异常加热率,讨论了5-8月青藏高原加热异常对同期大气环流的影响。研究结果表明:(1)5月份,以4 K·d-1的速率加热高原大气12天后,500 hPa位势高度异常在鄂霍次克海附近为正值区、中国东北及堪察加半岛以南为负值区,出现了疑似波列结构,但200 hPa呈西正东负的二极分布。6月份这种波列结构更加明显,200 hPa形成了完整的类Okhotsk-Japan(OKJ)波列型。(2)在其他月份未出现类似的波列结构。7月,蒙古至鄂霍次克海及日本以东一带地区200 hPa和500 hPa的负位势高度异常连成一片;8月,日本以东地区转为正值中心、鄂霍次克海附近仍维持负异常。(3)随着异常加热的增强,沿6月波列传播路径上的各点的位势高度异常振幅基本成比例增加。(4)射线追踪分析结果显示,5、6月份的波射线路径分布类似,模拟路径位于纬向波数为3和4对应的射线轨迹之间。     

东亚夏季风的自然变率——NCARCam3模拟结果分析

利用季节循环的全球观测海表温度及海冰驱动NCARCam3全球大气环流模式的100a模拟结果,通过定义东亚夏季风指数,分析了模拟的大气内部变化中东亚夏季风的变化特征。结果表明：模拟的东亚夏季风自然变率主要表现为3—7a较显著的年际周期,并具有较明显的年代际变化特征。在弱夏季风年代,亚洲大陆海平面气压增强,日本附近及东亚沿海地区海平面气压降低;500hPa位势高度上,欧洲地区为负高度距平,里海附近地区为正高度距平,日本及其以东太平洋为负高度距平,易形成类似欧亚（EU）型的遥相关波列。在强夏季风年代,其环流异常分布基本与弱夏季风年代相反。模拟的东亚夏季风变化与夏季大气内部500hPa高度场上EU型遥相关波列的关系密切。     

北大西洋多年代际振荡正、负位相期间欧亚夏季副热带波列季节内活动特征及与印度降水的联系

利用美国国家环境预测中心与国家大气研究中心（NCEP/NCAR）逐日再分析资料,针对北大西洋多年代际振荡（AMO）两个不同位相,对逐候200 hPa经向风异常进行EOF分析,发现在AMO正、负位相期间,欧亚副热带波列的季节内活动存在明显差异。利用超前—滞后回归,对比了不同AMO位相下副热带波列及其相联系的印度夏季降水的季节内活动演变特征,分析有关的大气环流,探究波列影响降水的机制。结果表明:在AMO负位相期间,由格陵兰岛以南北大西洋经大不列颠岛、地中海、黑海—里海向南亚北部传播的副热带波列的季节内演变,在印度中部引起下沉,导致中部及西北部季节内降水减少,波列负位相相反;在AMO正位相期间,副热带波列西起冰岛以南北大西洋经丹麦南部、俄罗斯西部、中亚向南亚东北部传播,对应该波列的季节内演变,辐合上升区在印度中部和东西两侧,使得该区域季节内降水增加,波列负位相相反。于是,AMO通过调制夏季欧亚副热带波列的季节内活动,可以对印度夏季降水的季节内变化空间型及演变发挥显著影响。     

华东区域夏季行星边界层大气稳定度的气候特征及其与气溶胶的联系

利用1979-2008年夏季（6—8月）逐日NCEP／NACR再分析资料、MODIS卫星的气溶胶资料等,研究了华东区域夏季行星边界层大气稳定度的气候特征与年际变化,分析了大气稳定度和相应的加热场与气溶胶光学厚度（aerosol optical depth,AOD）的联系。结果表明：华东区域夏季行星边界层大气稳定度在空间上分布不均匀,时间上具有明显的年际变化。边界层中的非绝热加热率、大气稳定度及气溶胶光学厚度三者之间可能存在密切联系。利用经验正交函数分析了华东区域总体理查森数Rib的距平场,得到了边界层稳定度分布的3个主要模态,这3个模态所代表的边界层大气稳定度异常与夏季风环流异常密切相关,特别是P-J型遥相关波列和西太平洋副热带高压在中国东部大气边界层稳定度变化中可能起着非常重要的作用。     

2020年7月黑龙江极端少雨成因初探

利用黑龙江省62个气象站月降水量观测资料和美国国家环境预报中心再分析资料、中国气象局国家气候中心环流指数资料等,对2020年7月黑龙江极端少雨成因进行初步诊断分析。结果表明：（1）2020年7月黑龙江降水异常偏少,全省平均降水量仅75.0 mm,为1961年以来历史同期第2少。（2）黑龙江7月异常少雨年,同期500 hPa东亚沿岸自低纬至高纬呈东亚-太平洋遥相关型（East Asia-Pacific teleconnection,EAP）负位相分布,东亚副热带西风急流（East Asia subtropical westerly jet,EASWJ）明显偏南,低层中国东北地区至黄海附近呈现异常的反气旋-气旋式环流,黑龙江上空整层水汽辐散。2020年7月环流特征与少雨年同期相似,但急流中心及其北侧负异常区较少雨年同期明显偏强,且中心略有东移,东亚沿岸对流层整层风场的经向波列更为清晰。EASWJ异常偏南是2020年7月黑龙江降水异常偏少的关键环流因子。（3）2020年5月南海附近异常偏弱的大气热源和7月负位相分布的北大西洋涛动,分别通过东亚沿岸经向EAP遥相关波列和欧亚中高纬地区纬向波列促...     

The two responses of the East-Asian atmospheric circulation in early summer to the preceding El Nino event and their influence on the rainfall over China

利用NCEP/NCAR提供的月平均850、500 hPa位势高度场和风矢量场资料及NOAA气候诊断中心的海温扩展重建资料,同时利用NCEP的CAM3.0模式对厄尔尼诺气候效应进行了分析.外强迫为赤道东太平洋的异常海温,从9月积分至次年6月,对此进行了模拟,结果表明:(1)冬季厄尔尼诺达到强盛后对次年东亚初夏的环流有明显的影响,表现在低层菲律宾附近反气旋环流的增强和中高纬度OKJ类波列(主要为鄂霍次克海—日本东部—日期变更线以西副热带高压北部的波列)的活跃,而后者更容易被模拟,这两种环流方面的影响都能在资料中检测出来.当这两种异常环流的发展被模拟出来时,长江以南地区的多雨状态也能够被模拟,表明厄尔尼诺发生后,其对夏季风的发生、发展有滞后作用,从而加强向中国南方的水汽输送,但至6月由于OKJ波列的发展使波活动通量在北太平洋中西部产生大面积强烈散射使副热带高压偏南,因而又抑制了夏季风的进一步向北推进,从而只停留在长江及其以南地区,这可能是致使降水南多北少的原因之一;(2)中国南方降水多寡受到鄂霍次克海高压及菲律宾反气旋的共同影响,两者任何一方加强时南方降水增多,反之亦然.近年来受鄂霍次克海高压的影响更为突出,鄂霍次克海高压、南北方降水、厄尔尼诺事件以及菲律宾反气旋都存在相近似但又各自不同的年代际变化规律,其共同影响与中国南涝北旱的年代际降水格局变化有密切关系.     

AN EMPIRICAL ORTHOGONAL FUNCTION ANALYSIS FOR THE WAVE TRAINS IN EAST ASIAN SUMMER

This study examines the wave trains at 500 hPa occurring in East Asian summer by using the Empirical Orthogonal Function (EOF) analysis as a diagnostic tool. The results are summarized as follows: (1) A wave train pattern (OKJ pattern) originating from the upstream areas of the Sea of Okhotsk to the subtropical regions could display its strong signal in early and middle summer. The OKJ pattern is clearly recognized in the first EOF component in Eurasia. (2) The other wave train pattern originating from the Philippines via Japan to North America (the P-J pattern) shows quite strong signals in the whole summer. Although the P-J pattern is described as the second EOF component around the area from East Asia to Northeast Pacific Ocean, the variance contribution is the same as that of OKJ pattern in the first EOF component. (3) The composite analyses indicate that the OKJ and P-J wave trains could coexist to some extents.     

Construction of the OKJ teleconnection index

This study focuses on the construction of an index to measure Okhotsk–Japan (OKJ) teleconnection pattern that mainly occurs in early summer. There are three major results presented here. The first is that four indices were developed to describe the OKJ pattern occurring in the monthly mean height field by using one point correlation and empirical orthogonal function (EOF) analysis. Although there is no substantial difference among them, the third OKJ index (OKJ-III) gives a better result for the OKJ pattern when correlated with height field at 500 hPa in June. Second, there exists a significant positive correlation between the East Asian monsoon index and the OKJ-III in June. The positive OKJ-III is associated with the positive anomalies of precipitation rate to the south of the Yangtze River and Northeast China in June and negative anomalies of the surface air temperature over Japan in June through August and vice versa. All of these coincide well with the features of Rossby wave propagation in OKJ pattern that were summarized in previous studies. This index that simply represents the strength of the OKJ propagation can be used as a diagnostic tool to assess East Asian summer monsoon climate, especially for the month of June. Third, the OKJ pattern can be detected by using the first principal component of the EOF analysis in June 500 hPa height field, and it accounts for large portion of the total variance. Such a strong OKJ signal was not found in the rest of the summer months, i.e., July and August. These results strongly suggest the importance of the OKJ pattern in the East Asian circulation of early summer.     

北方雨季中国东部降水异常模态的环流特征及成因分析

根据1958～2011年中国东部（105°E以东）316站逐日降水资料及NCEP/NCAR逐日再分析资料,利用统计分析、物理量诊断等方法,探讨北方雨季（7月11日至8月31日）中国东部降水异常模态及同期、前期的大气环流特征。分析发现,北方雨季中国东部降水异常表现为三个相互独立的降水模态:第一模态为偏西型,当其时间系数为正（负）时,河套地区降水偏多（少）,江淮流域上游降水偏少（多）,南方大部降水偏多（少）;第二模态为北方一致型,当其时间系数为正（负）时,北方降水一致偏多（少）,长江流域降水偏少（多）;第三模态为偏东型,当其时间系数为正（负）时,东北南部至长江中游降水偏多（少）,华东沿海降水偏少（多）。研究发现,造成北方雨季三个降水异常模态的环流特征各不相同:偏西型降水主要受西亚高空副热带西风急流位置南北偏移影响;北方一致型降水主要由东亚-太平洋遥相关波列导致;偏东型降水主要与海陆气压异常对比造成的东亚夏季风变化有关。此外,三个模态与前期环流异常有密切联系。第一模态的正（负）异常由7月上旬200 hPa来自北大西洋的异常波列造成乌拉尔山位势高度负（正）异常和巴尔喀什湖以南位势高度正（负）异常引起。第二模态的正（负）异常与前期7月上旬200 hPa北大西洋上位势高度负（正）异常产生的沿中纬度（高纬度）路径向下游传播的波列有关。第三模态的正（负）异常由春季3月份低层蒙古上空异常的气旋（反气旋）持续至同期造成。     

Dominant Modes of Interannual Variability in Atmospheric Water Vapor Content over East Asia during Winter and Their Associated Mechanisms

Atmospheric water vapor content(WVC) is a critical factor for East Asian winter precipitation. This study investigates the dominant modes of interannual variability in WVC over East Asia during winter and their underlying mechanisms.Based on the empirical orthogonal function(EOF) method, the leading mode(EOF1, R~2 = 28.9%) of the interannual variability in the East Asian winter WVC exhibits a meridional dipole pattern characterized by opposite WVC anomalies over northeastern China and eastern China; the second mode(EOF2, R~2 = 24.3%) of the interannual variability in the East Asian winter WVC exhibits a monopole pattern characterized by consistent WVC anomalies over eastern China. EOF1 is mainly modulated by two anomalous zonal water vapor transport(WVT) branches over northeastern China and eastern China, which are associated with an anomalous atmospheric wave train over Eurasia affected by sea ice cover in the Kara Sea-Barents Sea(SIC-KSBS) area in the preceding October-November(ON). EOF2 is mainly modulated by an anomalous westerly WVT branch over eastern China, which is associated with a circumglobal atmospheric zonal wave train in the Northern Hemisphere. This circumglobal zonal wave train is modulated by concurrent central and eastern tropical Pacific sea surface temperature anomalies. The SIC-KSBS anomalies in ON and the concurrent SST anomalies over tropical Pacific may partially account for the interannual variability of EOF1 and EOF2 winter WVC, and thus may provide a theoretical basis for improving the prediction of winter climate over East Asia.     

Revisiting the second EOF mode of interannual variation in summer rainfall over East China

The second EOF(EOF2) mode of interannual variation in summer rainfall over East China is characterized by inverse rainfall changes between South China(SC) and the Yellow River-Huaihe River valleys(YH).However,understanding of the EOF2 mode is still limited.In this study,the authors identify that the EOF2 mode physically depicts the latitudinal variation of the climatological summer-mean rainy belt along the Yangtze River valley(YRRB),based on a 160-station rainfall dataset in China for the period 1951-2011.The latitudinal variation of the YRRB is mostly attributed to two different rainfall patterns:one reflects the seesaw(SS) rainfall changes between the YH and SC(SS pattern),and the other features rainfall anomalies concentrated in SC only(SC pattern).Corresponding to a southward shift of the YRRB,the SS pattern,with above-normal rainfall in SC and below-normal rainfall in the YH,is related to a cyclonic anomaly centered over the SC-East China Sea region,with a northerly anomaly blowing from the YH to SC;while the SC pattern,with above-normal rainfall in SC,is related to an anticyclonic anomaly over the western North Pacific(WNP),corresponding to an enhanced southwest monsoon over SC.The cyclonic anomaly,related to the SS pattern,is induced by a near-barotropic eastward propagating wave train along the Asian upper-tropospheric westerly jet,originating from the mid-high latitudes of the North Atlantic.The anticyclonic anomaly,for the SC pattern,is related to suppressed rainfall in the WNP.     

东亚中纬度干旱/半干旱区降水年际变化及其可能成因

基于NOAA的全球陆地降水资料(PREC/L)1948～2003年56年的月平均降水资料、NCEP/NCAR月平均再分析资料以及英国气象局哈德莱中心的海温(Sea Surface Temperature,SST)资料,并根据多年降水平均图选定了东亚中纬度干旱/半干旱区,对该区域夏季(6～8月)降水进行了经验正交分解(Empirical Orthogonal Function,EOF)。EOF第一模态呈现出全区一致的变化类型,第二模态则呈现出以100°E为界东西相反的分布类型。通过分析干旱/半干旱区以及以100°E为界的东西两部分降水异常年的环流形势和海温并加以对比,结果表明:在环流场上,对应于东亚中纬度干旱/半干旱区降水偏多年,对流层中下层环流异常在中高纬度呈现为一个东西向波列,乌拉尔山东侧为正的高度异常,贝加尔湖附近乃至以东地区为低压槽所控制;不同的是,对应于100°E以西的干旱/半干旱区夏季降水偏多年,波列有所东移,并且西太平洋副热带高压有显著北抬;而对应于100°E以东干旱/半干旱区夏季降水偏多年,环流形势异常基本与整个干旱/半干旱区降水偏多年一致,只是在里海附近有一高度负异常。在200hPa纬向风场上可以看到,当西亚副热带急流偏南加强时,对应于100°E以西的干旱/半干旱区降水偏多;而当东亚、西亚风急流都有显著北抬且加强时,对应于100°E以东干旱/半干旱区的夏季降水偏多,这可能与急流所激发的次级环流有关。进一步对SST的分析表明,海温与100°E以东或以西干旱/半干旱区降水异常的关系也不一样。当前冬、前春赤道中东太平洋都有正的海温异常,而到夏季转换为负的海温异常,且南太平洋在前冬和前春呈现显著负海温异常时,整个干旱/半干旱区夏季降水偏多;当赤道中东太平洋海温在前冬、前春有正的海温异常并一直减弱,但能维持到夏季,并且北印度洋海温也存在类似的海温异常时,100°E以西的干旱/半干旱区夏季降水偏多;而当前冬中东太平洋海温较暖但其南部海域偏冷,到了前春这些异常维持,并发展到同期为大范围弱的异常冷海温时,有利于100°E以东的干旱/半干旱区夏季降水偏多。比较的结果还揭示出,对应于干旱/半干旱区以及100°E以东干旱/半干旱区的降水异常年,海温异常分布大致是一致的;而对应于100°E以西干旱/半干旱区的降水异常年,海温异常分布及时间演变则有较大差异。     

INFLUENCE OF THE SURFACE AIR TEMPERATURE OVER ASIAN-PACIFIC REGION ON THE SUMMERTIME NORTHEASTERN ASIAN BLOCKING HIGH*

Synthesis analysis and singular value decomposition (SVD) methods were used to study the impact of surface air temperature (SAT) over Asian-Pacific region on the summertime northeastern Asian blocking high (NABH) with NCEP/NCAR Reanalysis Data.The results showed that 500 hPa geopotential height and SAT fields over Asian-Pacific region shared the similar pattern of East Asian Pacific (EAP) wave train;there was steady remote response relationship between the EAP wave train in summer and the "+-+" pattern of tropical SAT in zonal direction from former winter to summer;there were two relative negative(positive) Walker circulations over the tropical Indian Ocean and Pacific when being more(less) summertime NABH. The influence of sea surface temperature anomaly (SSTA) on the summertime NABH was possibly as follows.The special distribution of SSTA in tropical zonal direction continuously forced the tropical convection and zonal circulation from former winter to summer,and led them to act anomaly.Finally the abnormal conditions were transported to middle-high latitudes through EAP wave train and yielded the advantageous or disadvantageous atmospheric circulation background for the summertime NABH.     

华南前汛期盛期中国东部降水异常模态的环流特征及成因分析

根据1958~2011年中国东部(105°E以东)316站逐日降水观测资料及环流逐日再分析资料,利用统计分析、物理量诊断等方法,探讨华南前汛期盛期(5月21日至6月10日)中国东部降水异常模态及对应大气环流特征和可能成因。分析发现,华南前汛期盛期中国东部降水异常表现为两个相互独立的降水模态:第一模态为华南全区一致型,当其时间系数为正(负)时,整个华南降水偏多(少),黄河中游降水偏少(多);第二模态为华南沿海东部型,当其时间系数为正(负)时,华南沿海东部降水偏多(少),而长江中下游降水偏少(多)。研究发现,造成华南前汛期盛期两个降水型的环流特征有明显差异:全区一致型降水主要受东亚高空西风急流南北偏移、副热带高压脊东西偏移及低层南海北部异常风场影响;沿海东部型降水主要由东亚高空西风急流强弱及位置异常、副热带高压强弱变化、低层日本以南西太平洋异常风场导致。此外,两个降水型对应环流异常的成因也各不相同。第一模态中高层环流异常由丝绸之路遥相关型导致,低层风场异常在5月下旬由阿拉伯海向下游传播的风场异常波列引起,在6月上旬则由西太平洋西移的异常反气旋(气旋)造成。第二模态的中高层环流异常先后由极地—欧亚遥相关型、环球遥相关型引起,低层风场异常由高层环流异常的动力作用造成。两降水型均存在整层深厚的垂直运动,但第一模态的垂直运动在高层闭合且对应显著的辐合辐散异常,第二模态则不具有上述特征。     

Circumglobal teleconnection and early summer rainfall in the US Intermountain West

Physical processes responsible for the abnormally wet condition in the Central Intermountain West (CIW) of the United States in June 2009 were investigated. It was illustrated that persistent rainy conditions over the CIW during June 2009 were associated with a pronounced circumglobal teleconnection pattern, which is characterized as a short Rossby wave train along the jet stream waveguide with a wave number 5 structure. The ascending motion and moisture flux convergence over the CIW associated with the cyclonic action center over the US West Coast in the teleconnection wave train could be essential for the persistent local rainfall during June 2009. Further analysis suggested that the June 2009 circulation pattern is consistent with a prevailing mode of the summer circumglobal teleconnection pattern. The findings in this study provide information for improved understanding of the early summer rainfall regime in the CIW.     

几种亚洲季风指数与中国夏季主要雨型的关联

首先采用EOF方法分析了中国夏季降水的主要特征 ,其第一 (EOF1 )和第二 (EOF2 )特征向量及其时间序列 (EOF1 - T、EOF2 T)基本上反映了中国夏季 1 (或 3)类和 2类主要雨型的空间和时间分布 ;进一步建立了EOF1、EOF2及其对应的时间序列EOF1 - T、EOF2- T与季风指数的关联 ,以及中国夏季主要雨型与季风指数直接的关联。结果表明 :各季风指数都对中国夏季的 1类雨型有较好的反映能力 ,都对 2类雨型无反映能力 ,仅学者施能定义的指数对 3类雨型有一定的反映能力。