2013年1月持续性霾天气中影响污染程度的气象条件分析

利用南京本站气象观测记录、环保局监测数据以及NCEP/NCAR再分析资料,分析2013年1月持续性污染天气过程的大气环流背景,并结合南京地区探空资料、风廓线雷达资料以及激光雷达资料,分析这次持续性污染过程中空气质量属良好、轻度污染、中度污染、重度污染典型个例的大气垂直特征和边界层内气象条件的差异。得到如下结论:2013年1月份北方冷空气活动较弱,南京地区大气层结稳定,近地层风速小,污染物气象扩散条件差。加之近地层以弱偏东风为主,水汽较多,有利于污染物颗粒直径增大。大气垂直结构以及边界层内水平风速均对大气污染程度起到一定影响。AQI与逆温层高度存在显著负相关关系;大气污染时,1000 m以下出现逆温结构,且逆温层越低、越厚,污染程度越大;重度污染时,近地层出现贴地逆温层,厚度为700m左右。逆温层高度下降,PM₁₀颗粒物高浓度区高度也明显下降,近地层污染物浓度对垂直方向上污染物浓度正响应的高度降低。在空气质量良好时, 150~1500m存在风速大值区,且风无空,湍流作用明显,有利于污染物和周围的洁净空气相混合而得到稀释,加速污染物的垂直扩散进程。当中度污染日和典型重度污染日时,150~1500 m之间并不存在大风速区。此外, PM₁₀的300μg·m^-3高浓度垂直高度延伸至300 m附近时,近地层PM_2.5明显上升至100μg·m^-3以上,高浓度区数值越大,近地层PM_2.5越大。     

阿拉腾敖包风场风能资源分析与评估

选用杭锦旗1977—2006年各年逐月平均风速资料、2006年1—12月逐时风向、成速资料、2006年1一12月阿拉腾敖包测风塔逐时风向、风速资料，采用统计分析方法，对阿拉腾敖包风场风速和风功率密度、风速频率和风能频率分布、风向频率及风能密度方向分布、有效风能时数进行计算分析，得出阿拉腾敖包风场风能资源评价；给出了综合评估意见：该风场10m高度年平均风速5.7m?s^-1年风功率密度为147. 19W?m^－2; 60m高度年平均风速7.3m?s^-1,年风功率密度为336.65W?m^－2; 70m高度年平均风速7.6m.s^-1，年有效风速（3～25m?s^-1)时数为8410小时，年风功率密度为380.45W? m^－270m高度年主导风向为WNW风，春、秋和冬三季主导风向均为W风，因而风向较为稳定。年内春季风速较大，秋、冬季次之，而夏季最小。据初步测算，该风能区风能总储量约为152MW.     

台州低空逆温层特征分析

利用浙江省洪家气象站L波段雷达逐日探空资料,统计分析了2007—2011年台州接地逆温和悬浮逆温的出现频率、逆温厚度、逆温强度特征,以及与风向风速的关系。结果表明:台州四季均存在低空逆温层,低空逆温出现频率年变化趋势呈单谷型特征,冬春季节逆温出现频率较高。秋冬季节低空逆温厚度增大,春季厚度变薄,夏季最薄;各时次的悬浮逆温厚度大于接地逆温厚度。07:00接地逆温月变化和季节变化强度都弱于19:00接地逆温的;07:00接地逆温,冬季强度最大(1.4℃/100m);19:00接地逆温在秋冬季节强度(2.2和2.0℃/100m)显著大于春夏季节强度(1.3和1.5℃/100m)。两个时次悬浮逆温强度月变化(0.8~1.2℃/100m)和季节变化(0.9~1.1℃/100m)较小,平均底高和顶高的最低值都在7月份,19:00悬浮逆温平均底高、平均顶高普遍大于07:00悬浮逆温观测值。出现接地逆温层时,低空风速一般≤2 m/s,层底风向集中在W到NW之间和静风,天空多为无云或少云;出现悬浮逆温层时,风速小于6 m/s的比例超过50%,层底风向集中在NW到ENE之间和SSW到SW之间,总云量不小于6的比例达70%以上。四季均有霾出现,霾日出现频率年变化趋势与逆温出现频率都是呈单谷型特征。霾污染权重系数季节变化与两个时次的逆温厚度和07:00逆温强度的变化趋势基本一致:冬春季节的大于夏秋季节的;冬春季节霾的污染程度较为严重,污染权重系数分别为49.0和38.1。     

基于系留探空试验的古尔班通古特沙漠低空气象廓线解析?

利用2011年10月15—24日在古尔班通古特沙漠腹地系留气艇边界层试验的探测资料,分析了沙漠腹地近地层风、温、湿等气象要素廓线垂直分布特征及其变化情况,结论如下:(1)20时—08时存在逆温,08时逆温最强,逆温强度为2.85℃/100 m,逆温层高度为700 m,之后逆温逐渐消失;夜晚近地层湿度明显大于上层大气,在100 m高度差内,湿度先快速减小再缓慢增大,与白天相反,20时近地面出现逆湿,1 100 m高度湿度发生明显切变;逆温层以上风速随高度变化呈多峰态,逆温层范围内风速增大趋势明显,900~1 100 m之间存在200 m厚的恒风区,1 100 m以上风速再次增大,白天的风速小于夜间。(2)风速波动范围大约为2~8 m/s,近地面100 m范围内风速随高度快速增大,风向由东南风向南风转变,600~900 m之间风速变化减缓,风向由从南风逐渐向东风转变,以东南风为主,风速与风向同步改变。(3)600 m以下随温度升高湿度快速减小,600~1 100 m之间又持续增大,1 100~1 500 m之间呈波动变化的趋势,1500 m增大明显。(4)风切变指数夜晚大于白天,最大值在23时(20.88),最小值在中午14时(0.97),平均风切变指数为9.61。混合层厚度平均为125.88 m。     

雁荡山云海的时空变化特征及其与气象因子的关系

用北雁荡气象站1960—2012年气象要素资料,分析近50余年雁荡山云海时空变化特征以及云海与气温、降水、相对湿度、风速的关系。结果表明,雁荡山年平均云海日164.92 d,但年际差异明显,最多年份215d,最少年份58 d。年内差异也明显,春季最多,云海日(8成以上云海日)平均有50.89 d(32.77 d),秋季最少。各月云海日数与月平均气温相关不明显,但与相对湿度呈较明显的正相关关系,云海日数(8成以上云海日数)序列与月平均相对湿度序列的相关系数为0.82(0.64)。统计分析8成以上云海日与关键气象因子关系可得,云海出现当天或前一天一般都有降水,云海出现当天一般相对湿度≥80%、平均风速≤4.5 m/s。     

乌鲁木齐机场持续浓雾低空气象要素特征分析

利用乌鲁木齐市L波段雷达系统探空资料，对2014—2016年冬季12月至次年2月乌鲁木齐机场雾日、非雾日，雾日中持续浓雾日和非持续浓雾日的低空温、湿、风等气象要素特征进行了对比分析，结果表明：（1）雾日较之非雾日，近地层湿润层更厚，贴地逆温更厚更强（顶高950 m,强度0.55 ℃/100 m)。风速普遍略小于非雾日，地面为西南风，低空东南风厚度大，起始高度低于500 m，最大风速层低于1200 m。（2）持续浓雾日较非持续浓雾日，贴地逆温或悬垂逆温的第一逆温层底高和顶高更低，平均逆温强度更强，地面西南和近地层偏南风频数大，低空型东南风较强。第一逆温顶高低于600 m，悬垂逆温底高低于100 m，逆温强度大于0.55 ℃/100 m，低空型东南风起始高度高低于300 m，600 m高度以上东南风风速大于等于8 m/s等条件有利于持续浓雾的发生。     

低温弱光对设施番茄苗期营养物质和干物质分配的影响

本试验以PAR （光合有效辐射）800 μmol·m^-2·s^-1，温度25℃为对照（CK），设置6个处理[L1T1（PAR 200 μmol·m^-2·s^-1，4℃）、L1T2（PAR 200 μmol·m^-2·s^-1，6℃）、L1T3（PAR 200 μmol·m^-2·s^-1，8℃）、L2T1（PAR 400 μmol·m^-2·s^-1，4℃）、L2T2（PAR 400 μmol·m^-2·s^-1，6℃）和L2T3（PAR 400 μmol·m^-2·s^-1，8℃）]，分别处理6、12、24、48和72 h，以研究低温弱光双重胁迫对番茄苗期干物质分配以及不同器官的可溶性糖、可溶性蛋白和游离氨基酸含量的影响.结果表明：低温弱光双重胁迫使地下部分干物质分配比例减小，而对地上部分干物质分配比例无显著影响，地下部分的干物质分配比例随时间的变化与地上部分相反；低温弱光胁迫显著降低了番茄茎和叶片的可溶性糖、可溶性蛋白和游离氨基酸的含量；根的可溶性糖含量随胁迫时间的变化趋势与地上部分不一致，但根、茎、叶片的可溶性糖含量均以L2T3处理72 h含量最高，分别为94.88、77.09和41.62 mg·g^-1；根的可溶性蛋白含量随胁迫时间的变化趋势与地上部分不一致，茎和叶片的可溶性蛋白含量均以L2T3处理12 h最高，以L1T1处理72 h最低；不同器官的游离氨基酸含量随胁迫时间的变化趋势与可溶性蛋白相反；弱光对番茄干物质和营养物质含量的影响小于低温.研究证实苗期番茄在低温弱光胁迫前期，干物质和营养物质先向地上部分分配，胁迫24 h后则更多地向根系积累.     

塔克拉玛干沙漠北缘近地层气象要素变化特征

利用塔克拉玛干沙漠北缘哈德自动气象站2011年1~12月近地面层气象要素梯度观测资料,分析了该地区近地层风速、气温和相对湿度的日变化规律及四季廓线特征,并计算了哈德观测点大气稳定度和中性条件下的地表粗糙度。结果表明,哈德地区近地层0.5~10 m高度范围内气温、相对湿度和风速都呈现出明显的日变化特征。其中,风速为白天高、夜晚低,中午15:00各层风速均达到最大,凌晨04:00降至最低,其日变化幅度为1.1~1.7 m/s;14:00~15:00各层气温均为最大值,最低气温出现在05:00~06:00,昼夜温差大,最大温差为0.5 m处的16.5℃,下午17:00至次日09:00有逆温存在;相对湿度日变化在25%~55%之间,其变化规律与风速、气温的相反,凌晨06:00最大,下午15:00最低。哈德地区四季近地层风、温、湿廓线变化规律明显,14:00四季风速都呈指数形式增长,其中0.5~2 m间低层风速变化明显大于2~10 m间高层的变化;春、夏季气温主要以指数形式增长,冬季以线性增长为主,四季都有逆温存在;冬季的相对湿度明显大于其它季节。另外,哈德地区全年以东北风为主,2 m与10 m高度的主导风向一致,风频稍有差别。中性层结大气条件下的空气动力学粗糙度范围为1.42×10-11~1.7×10-3m,平均值为4.2×10-5m。     

华山云海的变化特征以及与气象要素的关系

用华山气象站1985—2014年气象要素资料,分析近30 a华山云海的变化及云海与降水、相对湿度、风速的关系。结果表明,华山年平均云海日为26.27 d,最多年份72 d,最少年份仅3 d;面积200 km~2云海年平均日数24.23 d;面积≥200 km~2云海平均日数2.87 d,最多有20 d (1985、1994年),最少有2 d(1997年),1997年后再没有面积≥200 km~2的云海出现。云海的出现呈逐年下降的趋势,年际差异明显。秋季云海出现日数最多(平均云海日数8.13 d),冬季最少(平均4.60 d);各月的云海日数8月最多,5月最少。面积≥200 km~2云海冬季出现日数最多,夏季最少;11月出现最多,3、12月次之,5月最少。面积≥200 km~2云海出现的前一天或当天一般都有降水,两天中至少有一天出现降水的几率是84.30%;平均相对湿度≥70%时,较易形成云海;云海日出现时常伴有风,但总体风速不大,通常≤10.0 m·s~(-1),利于云海的形成保持。     

河北省雾凇和雨凇气候特征及气象条件分析

利用1980—2009年河北省142个气象站的雾凇、雨凇资料、河北省南部94个气象站的地面观测资料和邢台探空资料,分析了河北省雾凇、雨凇的时空分布特征;利用箱线图分析了河北省南部适宜雾凇、雨凇出现的温度、湿度和风速等气象条件。结果表明：（1）在空间分布上,雾凇、雨凇主要出现在河北省南部,东部平原多,西部山区少;在时间分布上,雾凇、雨凇均出现在11月至次年3月。（2）适宜雾凇出现的气象条件是雾日并且气温在-7.2～-3.1℃之间、相对湿度≥92%、风速≤1.2 m·s~（-1）;雾凇出现时,95%的情况出现了逆温层。（3）适宜雨凇出现的气象条件是雨日并且气温在-4.1～0℃之间、相对湿度≥87%;雨凇出现时均有逆温层出现。（4）雾凇、雨凇高值区的相对湿度明显高于低值区,因此相对湿度大是雾凇、雨凇高值区形成的主要原因。     

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.     

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.     

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.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

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     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

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. Contributions from all over the world are welcome.SUBMISSIONAll submitted     

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.