和田河流域1954—2007年气温及降水气候特征分析

应用和田河流域和田市气象站1954-2007年逐月平均气温和降水量资料,采用趋势系数、Morlet小波分析法分析了54a来和田河流域气温、降水趋势变化及周期特征,结果表明：气温和降水变化呈暖湿化发展,气温线性变暖率为0.33℃／10a,降水线性递增率为2.1mm／10a,各年代变化趋势存有差异,但基本与西北地区气候变化趋势一致;小波系数的实部、模、位相信息准确揭示出了不同时间尺度下气温、降水的年际、年代际周期演变、强度变化以及突变特征。     

气候变化对和田河夏季平均流量的影响

选择和田河流域作为和田地区水资源的典型代表,和田河流域代表站和田市气象站1961～2004年的夏季高空500～300hPa气温、0℃层高度资料、和田河上游(乌鲁瓦提和同古孜洛克站)水文资料,分析了和田河流域夏季高空气温、0℃层平均高度和夏季流量的年际线性趋势变化。结果表明:近44a来和田河流域夏季高空500～300hPa平均气温和0℃层高度呈下降趋势,倾向率分别为-0.322℃/10a、-32.42gpm/10a;夏季流量也呈下降趋势,其倾向率为-7.26m3s-1/10a。和田河流域夏季高空500～300hPa平均气温和0℃层高度的下降等高空气候变化是和田河夏季流量减少的主要原因。     

近40年来西宁地区的气候变化研究

采用西宁地区4个有代表性的气象站1961—2000年的气温与降水资料，对西宁地区40a来的气候变化进行了统计分析。结果表明：近40a来该区气候变化表现出向暖湿变化的趋势特征，气温呈上升趋势，气候倾向率达0．34℃／10a，特别是90年代增温十分明显；降水量呈增加趋势，气候倾向率为25．24mm／10a。     

新疆吉木萨尔县45年气候变化特征分析

利用吉木萨尔县1961-2005年历年日平均气温、最高（低）气温、降水量、日照时数、风速等资料，分析该县45年年际、年代际、四季及近10年的气候变化特征。得出：（1）吉木萨尔县45年全年及四季气温变化均呈上升趋势，尤其冬季增温最明显，为0．62℃／10年；且近10年是45年中最暖的时期。（2）45年来平均月最高气温变化不大；而月平均最低气温增温明显，尤其近10年平均月最低气温达45年中的最高。（3）45年全年降水量变化呈增湿趋势，变化倾向率为8．19mm／10年，其中：冬季和夏季降水量呈逐渐增多趋势；而春季和秋季平均降水量则呈缓慢减少的趋势。不同年代际全年和夏季降水量均以1990年代最多，1970年代最少。近10年的年降水量也呈增湿趋势，其中冬季降水量为45年中最多时期；秋季降水量为45年中最少时期。（4）45年中任何时段的日照时数和平均风速变化均呈减少（小）趋势。对当地生态环境的改善和农业经济发展等都有十分重要的意义。     

青海省河南地区近35年来气候变化特征分析

根据青海省河南县气象站1981—2015年35a气温、降水量、日照时数等相关资料进行了分析,结果表明:近35a来河南地区气温有明显年际、年代际变化特征,并且以倾向率为0.6℃/10a的趋势呈线性上升,春季升温幅度最大,夏季最弱;年降水量以倾向率为6.9mm/10a的趋势呈线性减少,夏季降水量减少最大,其倾向率为-12.2mm/10a,35a期间多雨期和少雨期交替出现;日照时数以倾向率为54.95h/10a的趋势呈线性增加,各个季节增加情况不相同,其中春季日照时数增加最为明显,冬、春季较夏季明显,阶段性波动也较明显。     

近50年上思县气温和降水变化分析

采用上思国家气象观测站1961—2010年的气温与降水观测资料,运用一元线性回归方程、滑动平均等数理统计方法．分析近50a来气温和降水变化的总体特征和趋势,结果表明：上思县年平均气温呈上升趋势,线性倾向率为0．177℃／10a,冬季增温最为显著,线性倾向率为O．253℃／10a;上思县年降水量整体呈增加趋势,线性倾向率为7．27mm／10a,降水量增加的趋势不显著。     

近５１年宁强县气候特征分析

利用宁强县1957--2007年气温、降水量、相对湿度、日照时数和雾日数等气象观测资料,分析近51a来宁强县气候变化的规律和特征。结果表明：宁强县年平均气温呈现略微上升趋势,其气候倾向率为0．02。C／10a,其变化具有波动性;年降水量呈现出较明显的下降趋势,其气候倾向率为60．92mm／10a,降水的年际变化很大,且年内降水量分配很不平衡,主要集中在下半年和夏季,降水量主要分布在800～1500mm之间,降水量高于601mm的保证率达到100％;年平均相对湿度为79％;年平均日照时数为1589．0h;年雾日数呈现明显上升趋势,其气候倾向率为9．92d／10a,从1980年开始年雾日数急剧增加．雾日数的增加对农业会产生不利影响。     

近50a来洮河流域气候变化和干旱演变过程

利用洮河上游碌曲、中游岷县和下游临洮3站降水和气温观测资料,结合中游和下游2个水电站年径流量资料,分析近50 a来洮河流域气候及干旱变化特征。结果表明:近50 a洮河流域年平均气温整体呈现显著上升趋势,尤其在1997年前后明显升温,上游碌曲增幅最大,中游岷县、下游临洮增幅明显偏低,3站气温倾向率分别为0.43、0.15、0.14℃·(10 a)~(-1),且在1990年代中期以后发生突变;年降水量整体呈缓慢减少趋势,但1990年代中期以后有微弱增加,与年径流量变化基本一致;干旱指数显示,近41 a洮河流域大多数年份无旱,仅个别年份出现干旱,且程度较轻,下游地区干旱相对较重。     

西安近57年降水量变化分析

利用1951—2007年西安国家气象观测站二级站的月降水量资料,分析西安年代际、季和月降水量演变趋势。结果表明：西安年降水量总体呈下降趋势,20世纪90年代降水递减趋势明显。1991—2007年17a平均比历年（1951—2007年）平均减少28．7mm,比前40a（1951—1990年）平均减少40．9mm;季节降水量秋季、冬季为递增趋势,其中秋季递增率较大;春季、夏季为递减趋势。其中春季递减率较大,年代际平均递减率为9．7mm／10a。月降水量递减率较大的有：3,4,5,7,8月和11月,月降水年代际平均递减率分别为2,4,2,7,3,4mm／10a;6月,9月和10月降水量递增率较大,月降水年代际平均增长率分别为3,4,4mm／10a;其他月份随年代际变化不明显。     

果洛州玛多县49年气候变化特征分析

利用果洛州玛多县1961—2009年历年月平均气温、最高(低)气温、降水量、日照时数、蒸发、风速等资料,分析该县49年、四季、年代际及近10年的气候变化特征得出:玛多县49年年及四季气温变化均呈上升趋势,尤其是冬季增温最明显,变化倾向率为0.70℃/10年,且自90年代末以来是49年中最暖的时期;49年来平均最高、最低气温均呈上升趋势,冬季增暖最明显,变化倾向率分别为0.41℃/10年、0.92℃/10年,尤其是近10年平均最高、最低气温达到49年中的最高值;49年年降水量变化呈增加趋势,变化倾向率为13.75mm/10年,其中夏、春季降水增加最明显,变化倾向率分别为5.50mm/10年、4.71mm/10年。近10年的年降水量呈显著的增多趋势,变化倾向率为148.5mm/10年,其中夏季增多趋势最明显,变化倾向率为119.45mm/10年,冬季增多趋势最小,变化倾向率为0.45mm/10年。不同年代际年和夏季降水量均以近10年为最多,60年代年降水量最少,80年代夏季降水量为最少;49年中任何时段的日照时数均呈增多趋势,变化倾向率为32.5小时/10年;蒸发量呈不明显的减少趋势,变化倾向率为-1.16mm/10年,尤其夏季减少最明显,达-10.91mm/10年,其它季节呈增多趋势;年平均风速70-80年代为大值期,60年代风速最小,90年代至21世纪初为次小值期。     

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.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on     

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.     

Information for Authors

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

Information for Authors

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 Scope Advances in Atmospheric Sciences(AAS)is an international journal on the dynamics,physics,and chemistry of the atmosphere and ocean with papers across the full range of the atmospheric sciences,co-published bimonthly by Science Press and Springer.The journal includes Articles,Note and Correspondence,and Letters.Contributions from all over the world are welcome.