遵义市近10 a来降温频次及强度分析

选取遵义市13个国家站2010—2019年逐日日最低气温资料,将降温过程分为弱降温、较强降温、强降温、寒潮4个等级,分析了各级降温过程的频次、持续日数、降温幅度、过程最低气温、空间分布等特征。分析表明:(1) 10 a来遵义市共发生降温过程11 915站次,平均每站每年91.7次,以降温幅度在6℃以下的弱降温为主。(2)近10 a遵义市平均过程降温幅度为3℃,平均过程最低日低温11.9℃,持续时间在1～10 d之间,寒潮、强降温、较强降温持续天数以2～3 d为主,弱降温过程大多持续1 d。(3)不同等级降温频次空间分布与地形相关,较强降温以上的降温过程主要集中出现在遵义市娄山以南地区,弱降温主要出现在娄山山区及其西北部。(4)寒潮、强降温、较强降温主要出现在春秋季,寒潮主要出现在3月份,而弱降温在夏季发生频次较高,4月份是遵义市降温最剧烈的时候。     

遵义市近10 a来降温频次及强度分析

选取遵义市13个国家站2010—2019年逐日日最低气温资料,将降温过程分为弱降温、较强降温、强降温、寒潮4个等级,分析了各级降温过程的频次、持续日数、降温幅度、过程最低气温、空间分布等特征。分析表明：① 10 a来遵义市共发生降温过程11 915站次,平均每站每年91.7次,以降温幅度在6 ℃以下的弱降温为主。②近10 a遵义市平均过程降温幅度为3 ℃,平均过程最低日低温11.9 ℃,持续时间在1~10 d之间,寒潮、强降温、较强降温持续天数以2~3 d为主,弱降温过程大多持续1 d。③不同等级降温频次空间分布与地形相关,较强降温以上的降温过程主要集中出现在遵义市娄山以南地区,弱降温主要出现在娄山山区及其西北部。④寒潮、强降温、较强降温主要出现在春秋季,寒潮主要出现在3月份,而弱降温在夏季发生频次较高,4月份是遵义市降温最剧烈的时候。     

萧山市冷空气活动概况

1 资料与标准 根据萧山市气象站1955～1996年共42年的9月至次年4月的逐日压、温和风等三要素确定冷空气影响初日,用日平均气温过程降温幅度作为冷空气强度的划分标准。 中等冷空气:过程降温幅度5.1～7.0℃;较强冷空气:过程降温幅度7.1～9.9℃;强冷空气:过程降温幅度≥10.0℃;寒潮:日平均气温24小时降温≥10.0℃或48小时降温≥12.0℃,且日T_L≤5.0℃。     

1954-2016年阿勒泰市春季寒潮过程频数及强度气候特征

利用阿勒泰基准气候站日最低气温资料,资料长度从1954年到2016年的春季（每年2月26日至5月31日,共计63年）,以日最低气温及其降温幅度为指标,整理出阿勒泰市63年寒潮过程数据库,分析阿勒泰市近63a来寒潮过程的频数以及强度相关6个指标的气候特征,结果表明：（1）1954～2016年春季（3～5月）阿勒泰市共发生寒潮天气过程226次,平均每年发生3.6次。3月平均每年出现1.8次, 4月1.1次,5月0.7次。共有17a为寒潮发生异常偏少年份,16a为异常偏多年份。3月上旬和3月中旬为寒潮天气过程发生最多的时段。（2）春季寒潮频数以每10a/0.1次的速率在递减。月际尺度上,3月和5月发生寒潮天气过程递减,4月递增。年代际1950年代最多,2010-2016年最少。（3）春季寒潮天气过程持续日数在1～7d,其中持续2d的寒潮过程最多,占春季寒潮过程的49%。持续时间在1～3d的寒潮天气过程占92%。（4）春季寒潮降温过程平均降温幅度为-12.7℃,降温幅度平均值最大在3月。最大24h、48h和72h降温幅度平均值分别为-8.9℃、-12.5℃和-14.3℃。（5）春季寒潮降温过程最低气温平均值为-11.8℃。寒潮降温过程最低气温平均距平值为-7.6℃。     

江西省2003年7～9月重要天气过程评述

1罕见高温酷热天气2003年夏季7～9月我省受强盛副高控制,出现了罕见持续高温天气(表1)。2冷空气过程2003年9月19～21日,我省出现了1次中等偏强冷空气过程,日平均气温由28～29℃下降到20～22℃,过程降温幅度为7～8℃。表17～9月全省高温日统计一览表月份≥35℃超过40站的天数≥38℃超过10站的天数≥40℃超过1站的天数7月8月9月合计30d18d6d54d(超历史)16d9d1d26d(超历史)12d8d0d20d(超历史)江西省2003年7～9月重要天气过程评述$江西省环境预报中心@尹洁…     

嘉鱼县寒潮预报指标初探

1 嘉鱼站冬半年寒潮天气的气候统计 寒潮是冬半年的一种大型天气过程,即北方强冷空气大规模南侵造成的剧烈降温现象。根据中国气象局规定:24小时内日平均气温下降≥8℃或一次过程连续降温≥10℃,同时最低气温降至5℃以下,定为一次寒潮过程。     

1951—2015年乌鲁木齐市降温过程频数及强度气候特征

利用乌鲁木齐市气象站1951年1月1日至2015年12月31日的逐日气温资料,以日最低气温及其降温幅度为指标,整理出乌鲁木齐市近65年降温过程数据库,将降温过程分为Ⅰ级（弱）、Ⅱ级（中等强度）、Ⅲ级（较强）、Ⅳ级（强）以及Ⅴ级（寒潮）5个等级,分析了乌鲁木齐市各级降温过程的频数、持续日数、过程不同时段降温幅度、过程最低气温、过程最低气温距平偏低幅度等要素气候特征。结果如下：（1）1951—2015年,乌鲁木齐市出现降温过程5834次,平均每年89.8次,其中Ⅰ级（弱）降温过程占78.1%。降温过程的频数季节分布较均匀,但Ⅳ级（强）和Ⅴ级（寒潮）降温过程在春季最多。在降温过程异常偏多与偏少年之间,6—8月的过程频数差异最大,4和9月过程频数差异较小。年平均降温过程频数在7个年代际中差异不大;随年代际增长,Ⅰ级（弱）降温过程频数在增加,Ⅴ级（寒潮）降温过程频数却在减少。（2）1951—2015年,乌鲁木齐市5834次降温过程的持续日数平均为1.89 d,其中持续1 d的过程占49.0%。随降温过程等级由Ⅰ级到Ⅴ级提高,过程持续日数最高出现频率也从1 d过渡到3 d。Ⅳ级（强）和Ⅴ级（寒潮）降温过程均表现为秋末到冬季各月的持续日数长,春季各月短。（3）65年来,乌鲁木齐市过程降温幅度平均为-4.4℃,秋季降温幅度最强,夏季最弱。Ⅳ级（强）以及Ⅴ级（寒潮）过程的降温幅度最强的月份分别是6和12月。65年来,乌鲁木齐市降温过程的最大24、48和72 h降温幅度平均值分别为-3.1、-5.5和-7.4℃,最大24 h降温幅度是春季最强,冬季最弱;48 h降温幅度是春季最强,夏季最弱;72 h降温幅度是冬季最强,夏季最弱。（4）1951—2015年,乌鲁木齐市降温过程的最低气温平均值为0.3℃,冬季各月最低,夏季各月最高,带有显著的季节背景特征。过程最大日气温距平的平均值为-1.9 ℃,随降温过程等级由Ⅰ级到Ⅴ级提高,距平偏低幅度依次增强,Ⅴ级（寒潮）降温过程平均达到-8.5℃。（5）在乌鲁木齐市降温过程频数异常偏多月份,对应在500 hPa高空新疆主要受纬向西风气流控制,较稳定的西风气流上多短波槽脊东移影响新疆;在降温过程频数异常偏少月份,在500 hPa高空新疆主要受西北气流控制,处于高纬地区冷空气自北向南的侵袭通道上,更有利于较强冷空气入侵新疆。     

近64a阿勒泰市春季不同等级寒潮过程气候特征

本文整理出阿勒泰市64年各级别强度寒潮过程数据库，分析阿勒泰市近64a来各级别寒潮过程的频数以及强度相关6个指标的气候特征，结果表明：（1）1954～2017年春季阿勒泰市共发生一般寒潮过程109.5次，强寒潮过程75.5次，特强寒潮过程37.5次；平均每年春季分别发生1.7次、1.2次和0.6次；3种级别寒潮过程发生频次占寒潮过程发生总频次的48.2%、33.3%和16.5%，阿勒泰市春季主要以一般寒潮和强寒潮为主。（2）春季一般寒潮、强寒潮和特强寒潮过程频数年际变化均在递减，且不显著，其中4月一般寒潮和特强寒潮过程递增，特强寒潮过程频数递增明显；一般寒潮过程频数的年代际变化在1950年代最多，强寒潮过程1970年代最多，特强寒潮过程1960年代和2000-2009年代最多。（3）一般、强和特强寒潮过程持续时间分别在1～7d、1～6d和1～5d，均以持续1～3d为主，分别占各自寒潮过程总次数的94.5%、90.8%和90.0%，其中又都以持续2d最多。（4）一般寒潮、强寒潮和特强寒潮过程降温幅度平均值分别为-10.8℃、-13.0℃和-17.3℃，一般寒潮和强寒潮降温幅度均在5月最强，特强寒潮降温幅度在3月最强。（5）一般寒潮、强寒潮和特强寒潮降温过程最低气温平均值分别为-7.8℃、-12.8℃和-20.3℃，随时间的推移呈明显的抬升趋势。（6）1954～2017年阿勒泰市春季一般寒潮、强寒潮和特强寒潮中降温过程最低气温距平平均值分别为-5.7℃、-7.9℃和-10.5℃；三种级别寒潮过程最低气温距平为负值占该级别寒潮过程频数的比例分别为80.0%、97.4%和97.5%。     

江西省2003年10～12月重要天气过程评述

1大雾过程2003年10～12月,我省出现大雾的日数(全省每日15站以上大雾)共有5d,与常年相比属偏少(表1)。2降水过程2003年10～12月,我省降水明显偏少,未出现10站以上的暴雨过程,仅在12月19～20日赣北局部出现大～暴雨,上饶、抚州出现7站暴雨。3强冷空气过程2003年10～12月,我省共出现2次寒潮、1次强冷空气,1次较强冷空气过程(表2)。表1大雾过程一览表序号日期站数主要落区111月13日18站赣北211月30日52站全省312月1日27站全省412月13日18站中部512月17日15站中部表2寒潮、强冷空气过程一览表日期过程降温幅度过程最低气温与历史同期比较10月11~…     

北疆界限温度10℃初日变化及其对作物物候期的影响

用1971—2005年北疆31个气象站的界限温度10℃初日资料和乌兰乌苏站的物候期资料,分析了对冬小麦及柳树、杨树物候期的影响。结果表明,北疆界限温度10℃初日越来越早,进入90年代以来偏早的趋势更加明显。10℃平均初日北疆的2个迟中心,分别位于和布克赛尔和北塔山附近,初日出现较早的区域在博乐至石河子的北疆沿天山一带和伊犁地区。石河子10℃初日早的年份,积温高,日照充足,冬小麦的各平均生育期普遍提前2～19d,其中起身期提前19d,全生育期提前7d;柳树的各平均生育期普遍提前9～19d,其中展叶盛期提前19d。杨树的各平均生育期普遍提前4～12d,其中展叶盛期提前12d。     

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.     

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.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi 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.     

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.     

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     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

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.     

Retrieval of outgoing longwave radiation from COMS narrowband infrared imagery

Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed.