东北地区夏季气温变化特征分析

采用1951～2003年26个气象台站的夏季气温资料对我国东北地区夏季气温变化特征进行了分析。结果表明:近50多年来我国东北地区夏季气温主要经历了冷期、相对正常期和暖期3个阶段,夏季升温趋势达到0·15℃/10a,远超过全球、北半球、东北亚夏季的增暖程度。其对全球气候变暖的响应,一方面表现在夏季变暖、平均气温升高;另一方面表现在夏季气温变率加大;第三,气候变暖使东北夏季低温冷害明显减少、异常高温气候明显增多,但在变暖形势下局部发生低温冷害的现象仍然存在。     

近45年来云南8月低温的气候分析

利用１９５１－１９９６年云南气温资料,分析云南夏季低温的气候特征。分析指出,云南夏季低温冷害并不仅仅是障碍型冷害。４５年来云南出现５个低温年,与我国东北地区５个低温年不同,低温年主要出现在气温偏冷年代。     

1961-2016年广西双季稻低温冷害演变特征

利用广西双季稻区1961-2016年逐日气象资料和1986-2016年水稻物候观测资料,运用气候倾向率等方法研究气候变化背景下广西双季稻低温冷害演变特征。结果表明:(1)广西水稻生育期低温阴雨、五月寒、寒露风平均频率分别为84%、41%、81%,三种低温冷害的高值区均在桂北稻区,低值区一般出现在沿海地区。(2)广西绝大部分县区水稻低温阴雨总次数、总天数、强度呈微弱减少趋势;大部分县区水稻五月寒呈微弱减少趋势。(3)桂北稻区以及桂中、桂南稻区的部分县区寒露风总次数呈微弱增加趋势,其余县区寒露风总次数呈微弱减少趋势;绝大部分县区寒露风总天数及强度呈微弱减少趋势。(4)低温冷害年平均出现总次数、总天数、强度均是桂北桂中桂南,三个稻区低温冷害中五月寒强度最小,桂南、桂北稻区寒露风强度稍比低温阴雨强度大,桂中稻区则是寒露风与低温阴雨两者强度相近。     

基于聚类分析的中国东北地区气温和降水时空变化特征

利用1961-2010 年中国东北地区81 个代表站逐日气温和降水资料,采用旋转主分量分析（REOF）和聚类分析（CAST）相结合的方法,对东北地区年平均气温和年降水的时空变化特征进行了分析。结果表明：东北地区年平均气温呈显著的增加趋势,但区域性较为明显,北部和东部地区的升温幅度较小,西部和南部升温幅度较大;年降水量呈现减少的趋势,西部地区降水减少的趋势较为显著。     

中国冬季气温季节内变率特征及环流分析

利用中国冬季逐日平均气温均方差作为气温季节内变率指标,分析其变化特征并探讨引起季节内变率异常的环流背景。结果表明,中国冬季气温季节内变率总体呈减弱趋势,对气候增暖趋势响应明显,其年代际变化和东亚冬季风年代际转折时间相吻合。当气温季节内变率异常偏强时,冬季平均环流场上呈类似准正压结构,平流层极涡偏弱,对流层中高纬呈类似斯堪的纳维亚遥相关型分布,低层西伯利亚高压偏强,北大西洋涛动(NAO)为负位相;NAO同我国东部气温变率联系密切,进一步分析揭示出NAO是通过影响西伯利亚高压的高频变化来作用于气温季节内变率。最后,通过提取天气—次季节—季节不同时间尺度上的大气环流内部变率,发现在各个尺度上,气温季节内变率均受西伯利亚高压和东亚冷涡的调控作用;尤其在天气尺度上,阿留申低压频繁波动及上游欧洲脊的稳定少动与气温变率有密切联系,季节尺度上欧亚阻塞高压和鄂霍次克海阻塞高压异常对气温变率有显著影响。     

基于气候变化视觉下广西粮食安全生产的思考

从广西气候资源和主要农业气象灾害的变化特征及其对水稻等主要粮食作物的生长发育、产量、布局、种植制度以及病虫害等的影响角度,综合分析气候变化对广西粮食安全生产的影响。结果表明:广西近半个多世纪以来,气温明显增高,高温热害明显增多,低温冷害减少,但极端冷害时有发生;降水两极分化,极端强降水频率增加,旱涝灾害呈加剧趋势;日照时数呈"阶梯式"下降趋势。光温水气候资源条件时空格局发生了明显变化,使广西绝大部分地区早稻生育期呈提前趋势、晚稻生育期呈推迟趋势,使水稻的布局、种植制度发生改变,水稻病虫害加剧,同时,气候变暖所导致的极端气象灾害频发将对水稻等粮食产量构成很大威胁,进而影响广西粮食安全。针对气候变化对广西水稻等粮食生产的综合影响,提出广西水稻等粮食作物安全生产适应气候变化的对策具有十分重要的意义。     

黑河上游径流对极端气候变化的响应研究

为深入认知黑河上游径流变化与极端气温、极端降水指数间的关联机制,使用1960-2014年黑河上游祁连、托勒、野牛沟3个气象站点的逐日气温、降水资料和莺落峡水文站逐日径流量资料,通过趋势分析、相关分析、多元回归分析和主成分分析等方法,分析黑河上游极端气候指数和极端水文事件的变化趋势、极端气候指数与径流的相关关系以及径流对降水的滞后效应。结果表明:(1)黑河上游表征低温的极端气温指数呈下降趋势,表征高温的气温指数呈上升趋势。极端降水指数呈小幅增加趋势。年极端洪水总量呈增加趋势,极端枯水呈显著减少趋势,与黑河上游径流总量增加的变化趋势一致。(2)极端降水指数与极端洪水总量的相关性显著,说明黑河上游极端降水是影响极端洪水总量的主要因素。(3)洪水对祁连站降水量的响应存在1～2天的滞后期,初步分析得出黑河上游降水量的时间和空间差异以及东、西支河流河网密度的差异是产生滞后性响应的主导因子。     

近30年东北春玉米发育期对气候变化的响应

基于1981—2010年东北地区55个农业气象观测站发育期数据、16个气象站逐日气象资料,采用趋势变率、秩相关分析、主成分分析和结构方程模型等方法,分析了近30年东北春玉米关键发育期的变化特征,探讨了春玉米发育期对不同时间尺度气象因子的响应规律。结果表明:1981—2010年春玉米关键发育期 (播种期、抽雄期、成熟期) 均有延后趋势,大部分地区春玉米生长前期 (播种期—抽雄期) 日数减少,生长后期 (抽雄期—成熟期) 日数增加,全生育期日数增加。在绝大多数年份,春玉米播种期在温度适播期之后,成熟期在初霜日之前。近30年对东北春玉米生育期日数影响最大的气象要素为温度,主成分分析结果显示,年际尺度的升温、温度生长期的延长和作物生长期的高温对生育期日数影响显著;结构方程模型指出,作物生长期的最高温度和最低温度对生育期日数影响有间接效应,主导气象要素能够解释生育期日数变异的44%。全球变暖背景下,东北春玉米发育期变化是作物响应气候变化和农业生产适应气候变化的共同结果。     

广西气候变化事实

利用1961-2015年的气象观测资料,对广西气温、降水及高影响天气气候事件等进行气候变化趋势分析,得到广西气候变化的事实为:气温明显升高,城市升温更显著;高温热浪明显增多,低温冷害减少,但极端冷害影响严重;降水两极分化,极端强降水频率增加,旱涝灾害加剧;热带气旋影响个数减少,但强台风的影响严重;极端气象灾害造成的损失加大。     

ENSO对全球及中国农业气象灾害和粮食产量影响研究进展

厄尔尼诺-南方涛动（ENSO）是全球性年际气候变率的主导模式,ENSO通过影响全球的大气环流,对全球许多地区的气温、降水和由气温、降水异常导致的农业气象灾害（如低温冷害、旱涝灾害等）及农作物生长发育、产量形成产生影响。综述前人对ENSO影响研究进展,所得主要结论如下：1）从全球范围来看,厄尔尼诺年,全球气温偏高,陆地平均年降水量减少;拉尼娜年,全球气温偏低,陆地平均年降水量增加;不同季节和不同类型EN-S0对全球气温和降水的影响有差异。在中国,厄尔尼诺年,大部分地区冬春季气温偏高,夏秋季气温偏低,拉尼娜年,大部分地区冬春季气温偏低,夏秋季气温偏高,不同年代下ENSO对我国气温的影响有所变化;厄尔尼诺年,全国降水以偏少为主,且ENSO对我国不同地区降水的影响与ENSO类型、发展阶段和发生年代有关。2）厄尔尼诺年,我国北方大部分地区初霜冻偏早,吉林延迟型冷害增加,黑龙江低温冷害多发,华北和西北地区易发生干旱;拉尼娜年,我国北方大部分地区初霜冻偏晚,西北地区易发生洪涝。气候变暖背景下,厄尔尼诺与东北低温的关系更为复杂。ENSO循环的不同阶段会影响我国旱涝的地区分布。3）厄尔尼诺年和拉尼娜年,全球水稻、小麦和玉米均以减产为主,不同国家和地区影响各异。其中,厄尔尼诺年,美国、巴西和阿根廷玉米产量增加,中国和津巴布韦玉米产量降低,印度小麦和水稻及菲律宾、印度尼西亚的雨季水稻均减产;拉尼娜年,美国、巴西和阿根廷玉米减产,印度小麦和水稻增产。在中国,厄尔尼诺对水稻和小麦产量的影响程度与当地灌溉条件有关。以上结论可为我国防御低温冷害、干旱等农业气象灾害,保障粮食安全,制定科学政策提供理论参考。     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

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正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome.SUBMISSIONAll submitted     

A Brief Introduction to Marine Meteorological Science Experiment Base at Bohe Town,Maoming City,Guangdong Province

<正>With the support of specialized funds for national science institutions,the Guangzhou Institute of Tropical and Marine Meteorology,China Meteorological Administration set up in October 2008 an experiment base for marine meteorology and a number of observation systems for the coastal boundary layer,air-sea flux,marine environmental elements,and basic meteorological elements at Bohe town,Maoming city,Guangdong province,in the northern part of the South China Sea.     

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AIMS AND SCOPE
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome.     

Information for Authors

AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome.     

Information for Authors

正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences