和政县大一暴雨预报工具

和政县处于大陆腹地、高原东北侧边坡的临夏州的东南方,平均海拔在2千米左右。7、8两月大一暴雨历年平均约三次。从1970—1981年三十次降水大于25毫米的资料分析,其环流特征可归纳为三种类型。一、副高边缘的暴雨西太平洋副热带高压脊线北跃到30°N附近,588廓线通过33—38°N、105—110°E这一区域。副高西侧高空槽位于35°N、90—100°E,40°N、95—105°E 时,和政县     

1991年江苏梅雨期内水汽输送特征的诊断分析

本文采用60°E—160°E,60°N—5°S范国内,1000hpa至300hPa各标准等压面上经纬格距均为2.5°φ的格点场资料,计算了:(1)1991年两段梅雨期内(5月21日—6月19日、6月28日—7月15日)水汽总输送量,水汽涡动输送量,平均经向、纬向水汽输送量等;(2)固定区域(117.5°E—122.5°E、30°N—35°N)内务标准层上三段(加入梅雨中断期6月20日—6月27日)内东、西、南和北各剖面上水汽输送量及水汽收支;(3)固定区域内各剖面上整层的水汽输送和水汽收支的时间分布后,得出了一系列有意义的结果。     

夏季青藏高原低涡东移的初步普查

一、概论 我们把青藏高原低涡(主要考虑风场闭合环流,参见文献[1])的移动情况,按其减弱消失的区域不同,划分为三大类:高原低涡在100°E以西消失的为不移出型;移至100°—110°E四川一带减弱消亡的为中移型;东移至110°E以东的为东移型。普查1975—82年(1979年除外)5—8月期间,500hPa高原低涡及其东移情况(见表1)发现:夏季在高原上生     

THE EFFECTS OF THE ARCTIC SEA ICE ON THE VARIATIONS OF ATMOSPHERIC GENERAL CIRCULATION AND CLIMATE

The SST anomaly of the central-eastern equatorial Pacific and the arctic sea ice anomalies of the four districts lo-cated respectively in 160°E—110°W,110°W—20°W,70°E—160°E and 20°W—70°E are taken as five separate factors.And the relationship between each factor and the atmospheric general circulation and the climate is investigated byobservational analysis and numerical experiments.It is shown that the effects of the arctic sea ice anomalies on the varia-tions of atmospheric circulation and climate are comparable to or even in some cases greater than that of EI Ninoevents.So one should pay much attention to the study of polar sea ice anomalies in climate research.     

澳大利亚地区预报夏季热带气旋活动的一个可行方法

1.引言在南半球夏季时节,由于热带气旋所引起的强风暴雨能够使澳大利亚北部地区受到严重的损失,从1950年以来,澳大利亚地区(5°S—30°S;105°E—165°E)各年所观测到的热带气旋个数是4—18个之间。如果能够成功地预报出这种热带气旋频率的年际     

东亚经向型气压异常偶极模与冬季北太平洋关键区域海温的关系及其数值模拟试验

进一步从资料分析和大气环流模式的敏感性试验, 对西北太平洋海温异常与亚太中高纬度地区冬季海平面气压异常经向偶极模的关系及影响进行了研究。资料分析表明, 对应冬季亚太地区海平面气压的经向(ME)型偶极模, 西北太平洋中高纬度海温异常的影响存在两个重要关键区。尤其是(40°N～55°N, 150°E～160°W)海区的海温异常与冬季东亚经向型气压偶极模指数I_ME有明显正相关, (20°N～35°N, 125°E～170°W)海区的海温异常与指数I_ME有明显负相关。而上述两个关键海区的SSTA对经向型振荡模的影响, 主要是通过热通量异常的作用。敏感性模拟试验清楚表明, 西北太平洋关键区的海温异常对亚洲—太平洋地区冬季海平面气压场的经向偶极模有一定影响。区域1(42°N～62°N, 145°E～165°W)的负异常相对于其自身的正异常来说, 对亚太地区海平面气压场的负经向偶极模贡献更大, 而区域2 [(22°N～42°N, 135°E～175°E)和(26°N～42°N, 175°E～170°W)]的正异常相对区域1的负异常来说对负经向偶极模的贡献更大一些。但是, 单独区域1的负异常海温和单独区域2的正异常海温影响下的海平面气压场响应的负经向偶极模都会有不同程度的位置偏移。当存在区域1的负异常海温和区域2的正异常海温相互匹配的情况下, 亚洲—太平洋地区冬季海平面气压场的负经向偶极模特征更为显著。     

亚洲地区夏季风与热带东风急流的年际变化

本文利用美国海洋大气局出版的世界气候资料以及由日本气象厅出版的每日天气图资料。制作了1964—1980年6—9月中低纬度(40—160°E,25。s一50°N)南北半球总降水量和850毫巴、150毫巴月平均环流图,并以每月150毫巴层上10°N,40—110°E每     

青岛流亭机场海风特征分析及对飞行的影响

通过分析2008—2016年青岛流亭机场(简称青岛机场)各季节地面风向日变化规律,发现有两支海风环流影响青岛机场：一支是西支海风,风向210°～230°,一般上午影响机场,午后发展至最强,下午消失;另一支为南支海风,风向150°～170°,午后影响机场,下午取代西支海风,傍晚发展至最强,夜间逐渐减弱消失。两支海风夏季最为明显,南支海风强度季节性差异强于西支海风。海风对机场飞行的影响主要体现在两支海风引起的三种海风锋型低空风切变,分别为西支海风锋引起的侧风切变、两支海风环流相互作用引起的侧风切变以及南支海风引起的顺风切变,其季节及日变化规律为：夏季出现概率最大,春、秋季次之,冬季几乎不会发生;一天中最可能发生时段分别为08：00—11：00、12：00—15：00和15：00—17：00,具体时段在各季节略有差异。     

90°E—170°W热带地区云量的低频变化

使用日本静止气象卫星(GMS)观测的候平均云量资料,分析了1978年5月—1984年12月和1978年5月—1981年12月两个时期内,印度洋中部(90°E)至太平洋(170°W)热带地区云量的低频变化特征。主要结果如下: 1.考查地区的云量存在两类低频振荡:30—60天的季节内振荡和周期为2—4年的年际振荡(可称之为甚低频振荡)。 2.在非厄尼诺时期,30—60天的低频振荡较明显,可以一直东传到中太平洋;有厄尼诺影响时,它的东传过程将受到抑制,主要限于130°E从西地区。 3.130°E以西地区的2—4年振荡,主要与厄尼诺/南方涛动的信息有关;在非厄尼诺时期,这一类振荡消失。     

亚洲地面气温异常对中国汛期雨带位置的影响研究

利用1980—1999年NECP/NCAR地面气温资料和中国气象局国家气象中心中国汛期雨带类型资料,计算并分析了亚洲地区地面气温与中国汛期雨带位置的关系。结果表明,亚洲地面气温与中国汛期雨带位置关系最好的区域在青藏高原,该地区的地面气温与中国汛期雨带位置之间的正相关关系具有较好的持续性,其中关系最密切的时间是5月份。对相应大气环流的合成分析发现,当5月青藏高原地面气温偏高时,热力作用使得高原地区上升气流加剧,并在115°E,25°N附近强迫出一支相对偏强的下沉气流,导致在110°～120°E,20°～25°N附近出现一个相对的反气旋性环流,该环流有利于夏季西太平洋副热带高压的北上,最终使得中国汛期雨带位置偏北。     

Synoptic analysis of dust storms in the Middle East

Dust storm in the Middle East and south-west Asia is a natural hazard and the Tigris-Euphrates alluvial plain has been recognized as the main dust source in this area. In this study, more than 60 dust storms that occurred during the period 2003–2011 are investigated on the basis of MODIS satellite images, and 12 of the dust storms are selected for synoptic analysis using the NCEP-NCAR Reanalysis Data. The potential dust sources in the Middle East and south-west Asian region (20°E to 80°E, 5°N to 50°N) are analyzed and used in the synoptic analysis. Dust storms in the region can be grouped into two main categories, i.e., the Shamal dust storms and the frontal dust storms. Synoptic systems, associated with the two categories, are distinguished and the frequency of the patterns is identified. For 68% of the Shamal dust storms, a high pressure system is situated between 0°E to 30°E and 27°N to 45°N, and a low pressure system between 50°E to 70°E and 23°N to 43°N. For 86% of the frontal dust storms, a high is located between 51°E to 67°E and 18°N to 33°N and a low between 28°E to 48°E and 32°N to 43°N. Three main patterns for Shamal dust storms are identified, which represent about 60% of the Shamal dust storms. This analysis confirms that the Shamal is related to the anticyclones located over northern Africa to Eastern Europe and the monsoon trough over Iraq, southern Iran, Pakistan and the Indian Subcontinent. The analysis also shows that the main dust sink for the frontal dust storms in Tigris and Euphrates alluvial plain extends from center of Iraq to west and center of Iran and, in most severe cases, to northern Iran and the southern coast of the Caspian Sea.     

ANALYSIS ON THE CHARACTERISTICS OF TROPICAL CYCLONES MAKING LANDFALL ON DIFFERENT REGIONS OF CHINESE MAINLAND

The locations(longitudes and latitudes)of the tropical cyclones(TCs)making landfall on the Chinese mainland from 1949 to 2008 are investigated in detail by using ArcGis and FORTRAN routine.The southeast coastline[110 to 122°E)with most landfall TCs was selected as the key region,which was divided into 12 subsections with 1°intervals of longitude.The study period was from July to September in each year.The result showed that the average sustaining time of TCs making landfall on the subsections east of 118°E is longer than those west of 118°E.Before landfall,the averaged TC intensity in the subsections east of118°E is stronger than that west of it.After landfall,however,the difference between the west and east is not significant.The index of destructive potential for the period before/after landfall was defined as TDP1/TDP2.The maximum of TDP1/TDP2 occurred in the subsection of[119,120°E)/[110,111°E).The ENSO impact on the frequency and average location of landfall TC over the whole region at 110 to 122°E is not obvious,but the effect varies with specific subsections.There is little differences of averaged TDP1 in the subsections between different phases of ENSO events,but the averaged TDP2 is larger in the warm events than that in the cold events.The rainstorm days of each station caused by TCs in different subsections were counted respectively.The results suggested that the rainstorm days of the subsections east of 118°E are much more than those west of 118°E.The larger values are primarily distributed at the subsections of[119,120°E)and[110,111°E).     

Observation research of the turbulent fluxes of momentum,sensible heat and latent heat over the West Pacific Tropical Ocean Area

This paper describes results of the fluxes of momentum , sensible heat and latent heat for the West Pacific Tropical Ocean Area ( 127 ° E - 150 ° E , 5 ° N -3 ° S ). The data were collected by the small tethered balloon sounding system over this ocean area including 6 continuous stations (140 ° E. 0 ° ; 145 ° E, 0 ° ; 150 ° E, 0 ° ; 140° E, 5 ° N; 145 ° E, 5° N and 150 ° E, 5 ° N) from 11 October to 15 December, 1986 . These fluxes were calculated by the semiempirical flux-profile relationships of Monin-Obukhov similarity theory using these observed data. The results show that for this tropical ocean area the drag coefficient CD is equal to (1.53 ± 0.25) × 10 3 and the daily mean latent flux Hl is greater than its daily mean sensible flux HV by a factor of about 9.     

南海周边越赤道气流的多时间尺度变化特征及其与环流和降水的联系

利用NCAR/NCEP-1再分析资料、NOAA的OLR资料以及GPCP降水资料等,通过功率谱分析、超前滞后回归等方法,对夏季南海周边105 °E、125 °E以及150 °E三支越赤道气流进行了多尺度特征分析,重点探讨三支越赤道气流季节内振荡与热带大气环流异常及南海周边降水的联系。结果表明,在季节内时间尺度上,105 °E与125 °E越赤道气流均具有10~20 d以及30~60 d低频振荡显著周期,而150 °E越赤道气流则以10~20 d周期为主。在年际尺度上,105 °E、125 °E、150 °E越赤道气流分别具有2~4年、2~3年、2~6年振荡周期。无论是季内还是年际变化,皆以105 °E与125 °E这两支越赤道气流之间关系较密切。南亚-南海-西太平洋地区对流层低层10~20 d振荡的气旋(对流加强)和反气旋(对流减弱)的环流活动变化,决定着105 °E及125 °E越赤道气流的10~20 d振荡的演变。这两支越赤道气流之30~60 d振荡所伴随的异常变化与热带夏季季节内振荡(BSISO)的演变过程非常相似,而150 °E越赤道气流之30~60 d振荡所伴随的异常低频环流则与南半球热带辐合带关系密切。105 °E及125 °E越赤道气流的季节内振荡及年际异常均与南海周边降水异常密切相关。      

Brewer,SAOZ and Ozonesonde Observations in Siberia

Abstract

Regular ground-based measurements of total ozone are available over the full Russian territory using M-124 filter ozonometers, Brewer spectrophotometers, and Système d'Analyse par Observation Zénithale (SAOZ) spectrometers in the Arctic region where these observations are essential for evaluating ozone loss in winter. Daily measurements are performed by three Brewer spectrophotometers; these are located in Kislovodsk (43.7°N, 42.7°E), Obninsk (55.1°N, 36.6°E), and Tomsk (56.5°N, 85.1°E). Two SAOZ spectrometers are deployed at the Arctic Circle in Salekhard (66.5°N, 66.7°E) and Zhigansk (66.8°N, 123.4°E). In addition, regular winter–spring ozonesonde soundings are carried out in Salekhard. Altogether, they have provided the unique measurements over the eastern Arctic required for characterizing ozone loss during each winter and will also monitor the anticipated ozone recovery following the reduction of chlorine and bromine ozone-depleting substances in the atmosphere.     

Characteristics of Zonal Propagation of Atmospheric Kinetic Energy at Equatorial Region in Asia

Based on the daily NCEP/NCAR reanalysis dataset from 1980 to 1997, the zonal propagations of 850 hPa kinetic energy (KE) and meridional wind (v) at equatorial region are examined respectively. Results show that the strongest center of KE in the tropical Asian monsoon region is located at 75°-90°E, with the secondary over the Somalia low-level jet channel, i.e., about 50°E. East to 90°E, disturbances of both KE and v observed are mainly coming from the western Pacific Ocean and propagating westward to the Bay of Bengal (BOB) passing through the South China Sea. But the propagation directions of both KE and v are rather disorderly between the BOB and the Somalia jet channel. Therefore, the East Asian summer monsoon and the Indian summer monsoon are different in the propagating features of the disturbances of KE and v. Above facts indicate that East Asian monsoon system exists undoubtedly even at the equatorial region, and quite distinct from the Indian monsoon system, it is mainly affected by the disturbances coming from the tropical western Pacific rather than from the Indian monsoon region. The boundary of the two monsoon systems is around 95°-100°E, which is more westward than the counterpart as proposed in earlier studies by 5-10 degrees in longitude.     

45年间影响中国东海附近海区热带气旋统计特征

根据1961-2005年有编号的热带气旋资料,从时间和空间两个方面统计分析了影响中国东海附近海区（117°-131°E,22°-33°N）的热带气旋特征。结果表明,统计区域内的影响热带气旋具有明显的年际变化特征,年平均频数为8.6个,年频数与厄尔尼诺具有很好的相关性,厄尔尼诺年为影响热带气旋少频年;影响热带气旋主要集中在6-10月,持续时间多在1-4天之间;影响热带气旋大多生成于菲律宾以东洋面和关岛附近洋面,从统计区域的南侧和东侧进入,主要有西北、东北和转向3条移动路径。     

Radiowave propagation measurements in Nigeria (preliminary reports)

International conferences on frequency coordination have, in recent years, required new information on radiowave propagation in tropical regions and, in particular, on propagation in Africa. The International Telecommunications Union (ITU-R) initiated ‘radio-wave propagation measurement campaign’ in some African countries some years back. However, none of the ITU-initiated experiments were mounted in Nigeria, and hence, there is lack of adequate understanding of the propagation mechanisms associated with this region of the tropics. The Centre for Basic Space Science (CBSS) of NASRDA has therefore embarked on propagation data collection from the different climatic zones of Nigeria (namely Coastal, Guinea Savannah, Midland, and Sahelian) with the aim of making propagation data available to the ITU, for design and prediction purposes in order to ensure a qualitative and effective communication system in Nigeria. This paper focuses on the current status of propagation data from Nigeria (collected by CBSS), identifying other parameters that still need to be obtained. The centre has deployed weather stations to different locations in the country for refractivity measurements in clear atmosphere, at the ground surface and at an altitude of 100 m, being the average height of communication mast in Nigeria. Other equipments deployed are Micro Rain Radar and Nigerian Environmental and Climatic Observing Program equipments. Some of the locations of the measurement stations are Nsukka (7.4°?E, 6.9°?N), Akure (5.12°?E, 7.15°?N), Minna (6.5°?E, 9.6°?N), Sokoto (5.25°?E, 13.08°?N), Jos (8.9°?E, 9.86°?N), and Lagos (3.35°?E, 6.6°?N). The results obtained from the data analysis have shown that the refractivity values vary with climatic zones and seasons of the year. Also, the occurrence probability of abnormal propagation events, such as super refraction, sub-refraction, and ducting, depends on the location as well as the local time. We have also attempted to identify and calculate the most important propagation factors and associated data, such as k factor, that are relevant in considerations of propagation in tropical regions like Nigeria.     

Synoptic Verification of Medium-Extended-Range Forecasts of the Northwest Pacific Subtropical High and South Asian High Based on Multi-Center TIGGE Data

Synoptic verification of medium-extended-range forecasts of the Northwest Pacific subtropical high （NWPSH） and South Asian high （SAH） is performed for the summers of 2010-2012 using TIGGE data from four operational centers at the CMA,ECMWF,JMA,and NCEP.The overall activities of the NW-PSH and SAH are examined along with their local characteristics such as the spatial coverage of each high in the East Asian key area （10°-40°N,105°-130°E）,the mean position of the ridge of each high over 110°-122.5°E,the westward extent of the NWPSH ridge,and the eastward extent of the SAH ridge.Focus on the NWPSH and SAH is justified because these two systems have pronounced influences on the summertime persistent heavy rainfall in China.Although the overall activities of both highs are reproduced reasonably well in the TIGGE data,their spatial coverages are reduced in the East Asian key area and both of them are weaker compared with observations.On average,their ridges shift more northward relative to observations.The NWPSH ridge is less westward while the SAH ridge is generally more eastward early in the forecast but too westward later in the forecast.The JMA ensemble prediction system （EPS） produces the best mediumrange （1-10 days） forecasts of the NWPSH based on these metrics,while the ECMWF EPS produces the best medium-range forecasts of the SAH and the most reliable extended-range （11-15 days） forecasts of both highs.Forecasts of the spatial coverage of both highs in the East Asian key area and the mean positions of the ridges are generally valid out to lead times of 7-12 days.By contrast,forecasts of the longitudinal extent of the ridges are typically only valid to lead times of 5-7 days.All the four operational centers＇ models produce excellent forecasts of the mean zonal position of the SAH ridge.The ensemble mean forecast is more reliable than the control forecast over the areas where the NWPSH （20°-30°N,135°-165°E） and SAH （23°-30°N,70°-100°E） are most active.Forecasts of both highs have advantages and disadvantages in the peripheral areas away from their respective center of high activity.     

南支槽对四川地区降水影响的定量分析

对1981—2017年NCEP/NCAR逐日再分析资料采用客观方法识别南支槽活动,并结合四川地区156个国家观测站的逐日降水资料,统计分析了南支槽的时空分布特征及其对四川地区降水的影响。结果表明:①南支槽平均每年出现47.9次,月分布呈双峰型,1月和5月出现频次最高;②出现最多的区域为孟加拉湾以北、青藏高原南侧的90°E附近,22°～24°N地区;③11月至次年1月为南支槽的增强期,南支槽强度大致上随着经度的增加而减小,但在86°E和96°E附近为增强区;④南支槽活动同期,约73.97%的对应时段四川地区有降水过程,降水频率大值区主要位于盆地西南部和南部;⑤南支槽位置偏西时四川地区更容易出现降水过程,但呈现出较强降水过程对应的南支槽强度较弱的现象。