最近40年中国雾日数和霾日数的气候变化特征

根据1971～2010年567个中国地面观测站点的雾日数和霾日数资料,分析了我国雾日数和霾日数的空间分布、季节变化以及年代际变化特征,并且利用REOF（旋转经验函数正交）分解对雾日数进行气候区划。结果表明：（1）雾主要分布在东南沿海地区、四川盆地地区、湘黔交界、山东沿海以及云南南部等地区。霾主要集中于华北、河南以及珠三角和长三角地区。（2）在季节变化上：秋、冬季雾和霾的分布大于春夏。（3）雾日数和霾日数年代际变化明显,雾日数在20世纪70至90年代较多,20世纪90年代以后减少;霾日数自2001年以来急剧增长。（4）雾日数可以共可分为10个区,其中华北区、川渝区以及长江中下游区是雾出现频率较高的几个重点区域。     

甘肃中部雷暴天气变化的气候特征分析

利用1958-2005年白银地区4测站观测资料,采用线性趋势估计、子波分析等数理统计方法,对白银地区雷暴初、终日及雷暴出现日数气候变化特征进行分析。结果表明:雷暴初日北部平原呈推迟的趋势(2.7 d/10 a),南部山区在其平均期(4月20日)附近上下摆动。雷暴终日北部平原呈提前趋势(-2.6 d/10 a),南部山区呈抛物线变化趋势,先升后降;雷暴初日变化北部平原较南部山区稳定,雷暴终日变化南部山区较北部平原区稳定,雷暴初日较终日稳定;雷暴初、终日北部平原对应的候平均气温阈值分别为9℃、11℃,南部山区对应的候平均气温阈值皆为6℃;雷暴日数“南多北少,”20世纪80年代中期以前8-10 a的周期显著,其总趋势是减少的。     

福建近44年雾日趋势变化特征及可能影响因素

应用1961—2004年福建省50个气象站逐月大雾及浓雾日数资料, 分析了全省大雾日数及浓雾日数的年、季分布特点、长期变化趋势、年代际变化特征以及可能的影响因素。结果表明:全省年、季雾日数分布均表现为中部及三明西部的多雾区, 沿海及南部地区的少雾区, 而多雾区中浓雾所占的比率达30%以上; 全省年、季大雾日数大部分地区表现为明显的减少趋势, 仅在龙岩西部呈增加趋势, 而浓雾的减少趋势不如大雾; 年、季雾日数具有明显的年代际变化特征, 年、季雾日数在20世纪80年代中期左右转为明显偏少期, 之前则为明显的偏多期。文中还重点分析了6个代表站大雾与浓雾的趋势与月际分布特征。进一步研究指出, 年雾日数与年平均气温有较好的负相关关系, 而与年平均相对湿度有很好的正相关关系, 同时与森林覆盖率的变化有一定关系。     

1961~2005年中国大雾天气气候特征

利用1961～2005年中国541个地面台站观测的能见度和相对湿度资料,分析了中国大雾时空分布特征和趋势变化特征.结果表明:中国大部分地区冬半年大雾日数明显偏多.夏半年明显偏少.其中11月最多,6月最少.在空间分布上,中国东部降水量较多的平原和丘陵年均大雾日数较多,而内蒙古大部和中国西部大部分地区年均大雾日数较少,多在1天以下.长江中下游和黄淮地区一些省市,是大雾天气多发的地区,并且具有明显正变化趋势,年大雾天气日数呈波动增多的趋势,波动的周期大约为1.5年.1982、1987、1989～2000年和2002年是大雾日数较多的年份,而1967年则是大雾日数明显偏少的年份.     

黑龙江省公路雾的气候特征

利用1954～2006年80个站雾的观测资料和2006年的交通事故资料．分析黑龙江省公路雾的气候特征。从空间分布看,雾具有局地性,山区较平原地区多;从时间分布看,雾具有明显的年际、月际和日变化。     

鞍山地区大雾天气气候特征及成因探讨

利用1951—2014年鞍山地区大雾天气观测资料,采用线性趋势法和多项式趋势法分析了鞍山地区大雾天气的空间及时间变化特征。结果表明:1951—2014年鞍山地区年和季大雾日数呈东南部地区多、西北部和中部地区少的空间分布特征,同时各区域大雾日数的季节变化差异显著,东南部山区夏季和秋季(6—10月)为大雾多发季,其他地区深秋和冬季(11月至翌年1月)为大雾多发季;鞍山市各区域大雾日数趋势变化的差异较大,中部地区大雾日数呈减少的趋势,西部地区大雾日数呈弱增加的趋势,东南部地区大雾日数呈增加的趋势。近64 a鞍山地区区域性大雾过程最长持续时间为7 d,全区性大雾过程较少,一致性大雾过程仅出现8次;鞍山地区大雾天气受地形影响较大,具有明显的区域特征,平原地区大雾天气少、山区大雾天气多,且山区连续性大雾过程持续时间较长。鞍山地区大雾过程持续时间多集中在1—2 h,大雾天气出现时间主要集中在05—06时、08时和20时前后,大雾过程日最长持续时间为20—21 h。在1961—2010年鞍山地区大雾日数的年代际变化中,东南部山区大雾日数呈增加的趋势,中部地区大雾日数呈减少的趋势;特别是20世纪90年代以后,中部地区大雾日数减少明显,东南部地区大雾日数增加显著,区域性差异较大。同时,人类活动对气候环境的反馈影响可能也是鞍山地区大雾天气变化的一个原因。     

1969—2008年海南省雾的气候特征与变化趋势

利用海南省1969—2008年观测资料,对海南雾的时空分布气候特征及变化趋势进行分析,并利用观测的最低气温、相对湿度资料和NCEP/NCAR再分析资料对海南雾日数变化的成因加以分析。结果表明,海南雾日数在中部山区出现最多,其次是北部地区,南半部沿海地区则极少有雾出现;雾主要出现在9月至翌年3月,年雾日数呈减少趋势;最低气温升高是引起雾日数减少的主要原因,雾日数的减少与相对湿度的减小也是一致的;秋冬和初春季节夜间气温低,有利于雾的形成;海拔越高的地区,气温越低,则生成的雾越多;雾日数显著偏多年份850hPa大陆高压偏弱,偏少年份偏强;雾日数显著偏多年份500hPa西太平洋副高强度偏弱,范围偏小,偏少年份则相反。     

盘县60余年来的暴雨气候特征及防御措施

利用盘县站1951—2008年的暴雨逐日观测资料,对盘县暴雨天气分布情况、年际变化及暴雨发生日数的气候变化特征等进行了分析,结果表明:盘县暴雨天气主要出现4—10月,集中出现在6—8月,其中6月最多,7、8月次之,11月到次年3月无暴雨天气出现;暴雨天气在20世纪50年代后期至60年代中期和80年代后期至90年代中期持续偏多;60 a来的暴雨总体呈上升趋势;持续性暴雨时空分布特征与暴雨相一致。     

湖北省积雪时空特征分析

利用湖北省77个测站1961-2007年气象资料,分析了积雪的时空特征。结果表明,湖北省积雪年际变化振幅明显,20世纪60年代到70年代中期缓慢增加,为积雪多发期;80年代年波动较大;90年代开始明显减少。月积雪日数呈准正态分布,1月最多,2月、12月次之。积雪空间分布表现为西部多,中东部少;山地多,丘陵平原少;沿江多...     

宁夏雾日和霜日的变化趋势分析

利用1961～2012年宁夏22个气象台站逐日天气现象、能见度、相对湿度资料,采用气候倾向率、趋势系数、最大熵谱分析、突变分析等方法,分析了宁夏各区域雾日数和霾日数的空间分布及变化趋势。结果表明：宁夏雾目数、霾日数均呈南北多、中间少的空间特征,但雾日数南部最多,而霾日数北部最多。近52a来,雾日数除南部山区呈不显著的减少趋势外,其他3个区域均呈增多趋势,而霾日数各区域均呈显著的增多趋势;另外,二者均有明显的阶段性演变特征,1961—1980年为明显偏少阶段,1981～2000年为波动变化阶段,2001年以后为明显偏多阶段;雾日数具有较明显的准7．5a,4．3a周期振荡,霾日数具有较明显的准4．6a、3,0a周期振荡;各区域雾日数与霾日数均未发生突变现象。     

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.     

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.     

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     

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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.