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1.
利用1996—2020年怀化常规地面观测资料和探空资料，根据地面冻雨观测记录，统计并总结了怀化冻雨时空分布特征，并利用探空资料分析了怀化冻雨形成机制及温湿垂直结构特征。结果表明：（1）怀化冻雨总体上呈南多北少的空间分布特点，其中北部沅陵冻雨日数最少（20 d），南部靖州最多（75 d）。从时间分布来看，最早从12月上旬开始，最迟于3月上旬结束，主要集中在12月下旬至2月中旬，1月下旬出现最多。（2）怀化冻雨的形成可分为冰相机制和暖雨机制，温湿结构可分为六类。其中暖雨机制冻雨占总数的473 %，冰相机制冻雨占527 %；平均云顶高度，暖雨机制均在36 km以下，冰相机制高于36 km；平均云顶温度，暖雨机制-66 ℃以上，最高17 ℃，冰相机制-30 ℃以下；平均地面温度，暖雨机制和冰相机制均＜0 ℃，暖雨机制＜-09 ℃，冰相机制＞-10 ℃；暖层顶高和底高，暖雨机制较冰相机制更高，冰相机制相差不大；暖层厚度，冰相机制基本在084 km以上，云顶温度越低，暖层厚度越厚。 相似文献
2.
一次低槽冷锋层状云系结构和过冷水分布特征的模拟研究 总被引：1，自引：1，他引：0
本文利用耦合了CAMS云微物理方案的WRF中尺度模式的模拟结果结合飞机、卫星、雷达、地面雨量等观测资料,对2012年9月25日山西一次低槽弱冷锋降水层状云系的宏微观结构和过冷水分布特征进行分析,试图研究低槽冷锋层状云系结构特征及过冷水形成的宏微观条件,为人工增雨作业提供依据。模拟的天气形势、降水、云顶温度、雷达回波、水成物的演变与实测基本一致。结果表明：此次降水过程的系统为低槽弱冷锋,且锋面后倾,位于锋前的云系前部为高层冷云,云顶温度-40℃左右,以冰相粒子组成,没有降水;锋区云系变成高层冷暖混合云,冷区以少量过冷水和大量冰相粒子组成,地面降水最大;处于锋后的云系后部为高层冷云,云顶温度-30℃左右,不存在过冷水,以较少冰相粒子组成,地面降水较弱。过冷水主要分布在锋面前方低于-5℃层,高度偏低、含量偏少,过冷水一方面因垂直上升速度供应水汽维持,另一方面因冰相粒子的凝华而消耗。过冷水层及其下部上升运动较弱、而其上部上升运动较强,不利于在过冷区长时间维持大量液态水,反而促使冰相粒子发展旺盛,此处水汽相对水面不饱和、相对冰面饱和,大量冰相粒子消耗水汽,不利于过冷水的存在,导致云场仅存在少量过冷水。本次过程中,冰核浓度的增大仅增大冰晶浓度,对雪霰含量及-5~0℃的过冷水几乎没有影响。 相似文献
3.
2008年1月南方一次冰冻天气中冻雨区的层结和云物理特征 总被引：7，自引：3，他引：4
2008年1月中下旬, 我国南方经历了四次历史罕见的冰冻雨雪天气。本文针对2008年1月25~29日的一次典型冻雨天气过程, 在实测资料、NCEP再分析资料综合分析的基础上, 利用中国气象科学研究院 (CAMS) 中尺度云分辨模式对1月28日~29日的冻雨天气过程进行了数值模拟, 研究了冰冻天气形成的大气层结及云系冻雨区云的宏微观结构特征, 初步分析了冻雨形成的云微物理过程及云物理成因。结果表明, 深厚而稳定的逆温层和低空冷层的存在是大范围冻雨出现的直接原因。此次南方冰冻过程中, 湖南和贵州两地冻雨形成的云物理机理不同, 不同冻雨区上空为两种不同类型的云, 对应两种不同的云微物理结构和大气层结结构。湖南冻雨区云层较厚, 云顶温度较低, 属于混合相云, 云中高层存在丰富的冰相粒子 (雪的比含水量最大)。湖南冻雨在 "冷—暖—冷" 层结下, 通过 "冰相融化过程" 形成, 即在锋面之上的对流层中层水汽辐合中心内形成的雪, 从高空落入暖层, 雪融化形成雨, 再下落到冷层后, 形成过冷雨滴, 最后接触到温度低于 0℃的物体或降落到地面上, 迅速冻结形成冻雨。而贵州冻雨区云层较薄, 云顶温度较高, 属于暖云, 中高层基本无冰相粒子, 低层为云水和雨水 (云水的比含水量最大)。贵州冻雨是在 "暖—冷" 层结下通过 "过冷暖雨过程" 形成的。即水汽沿锋面抬升, 在对流层中低层的水汽辐合中心内, 经过冷却凝结成云滴, 通过碰并云滴增长的雨滴下落到低空冷层, 形成的过冷却雨滴直接冻结形成冻雨。 相似文献
4.
东北冷涡中尺度云系降水机制研究 I: 观测分析 总被引：2，自引：2，他引：0
利用机载云粒子测量系统等仪器对2003年7月8日冷涡云系的积层混合云探测的资料,分析冷涡云系中的微物理结构、微物理过程和降水形成机制.结果表明:在4km以上高度,2-DC粒子浓度随高度快速增加,而粒子平均直径逐渐减小,粒子在下落过程中获得了增长.积层混合云中对流云在垂直方向上出现明显的分层的微物理结构:4.6km以上高度只存在针状冰晶;4.5～3.5 km高度,存在过冷水和冰相粒子.过冷水含量较高,冰相粒子除针状冰晶外,还有少量冰雪晶聚合体或霰粒子,其中在紧靠0℃层之上的3.5km高度,主要存在冰雪晶聚合体或霰粒子.在紧靠0℃层之下,粒子为椭球形,还有一些未完全融化的冰晶,再降低200 m高度,粒子完全是球形,这里完全是雨滴.降水粒子主要是雨水.云系液态水含量十分丰富,过冷水含量最大值可达3.3 g/m3,云体上部也达到2.0 g/m3.云垂直方向上微物理结构分析表明,云中冰晶除了通过冰核核化形成外,可能还存在冰晶的繁生过程.冰晶产生后通过聚并进一步长大,撞冻过冷水也是冰雪晶增长的方式之一.在云的暖区降水粒子为雨滴,其中至少有一部分是由冰相粒子(冰晶聚合体或霰粒子)融化形成.因此冷云过程参与了降水形成过程. 相似文献
5.
四川盆地降水云系飞机云物理观测个例分析 总被引：1，自引：0，他引：1
利用2008年10月26日晚至27日凌晨成都上空连续两架次飞机穿云观测资料,分析了探测云系的云物理特征和降水机制,以期了解四川盆地降水形成的云物理过程。结果表明：探测云系为上冷下暖的混合云系,云系深厚,云顶温度在-10℃左右,0℃层较高。云系中暖层厚,约3200 m;过冷层较薄,约1800 m。在过冷层中,从云顶往下,大云粒子谱和降水粒子谱明显拓宽。在暖层中,降水粒子的浓度和尺度减小。冰晶和过冷水的存在使得冷云过程得以发动,配合暖层中的暖云过程,降水现象得以实现。而过冷水不够充沛,形成的降水粒子不多,同时暖层中液态水含量少,供水不充分,使得地面降水强度不大,形成了小雨。 相似文献
6.
对云中微物理过程的研究是研究云降水形成过程和人工影响降水的重要基础,目前对积层混合云的对流区/对流泡中的微物理结构了解甚少。本文利用河北省“十三五”气象重点工程——云水资源开发利用工程的示范项目（2017～2019年）“太行山东麓人工增雨防雹作业技术试验”飞机和地面雷达观测数据,重点分析研究了2017年5月22日一次典型稳定性积层混合云对流泡和融化层的结构特征。研究结果表明,此次积层混合云高层存在高浓度大冰粒子,冰粒子下落过程中的增长在不同区域存在明显差异,在含有高过冷水含量的对流泡中,冰粒子增长主要是聚并和凇附增长,而在过冷水含量较低的云区以聚并增长为主。由于聚并增长形成的大冰粒子密度低,下落速度小,穿过0℃层时间更长,出现大量半融化的冰粒子,使融化现象更为明显。镶嵌在层状云中的对流泡一般处于0℃～-10℃（高度4～6 km）层之间,垂直和水平尺度约2 km,最大上升气流速度可达5 m s-1。对流泡内平均液态水含量是周围云区的2倍左右,小云粒子平均浓度比周围云区高一个量级,大粒子（直径800 μm以上）的浓度也更高。在具有较高过冷水含量的对流泡中降水形成符合“播撒—供给”机制,但在过冷水含量较低的区域并不符合这一机制。 相似文献
7.
根据NECP1°×1°客观再分析资料和常规观测资料,利用中尺度数值模式WRF对2008年1月25—29日长江中下游暴雪冻雨过程进行了数值模拟,结果表明：WRF模式可以很好地模拟出此次强降雪过程高低空环流形势演变特征以及降水带的分布。分析表明,中层西南急流对暖湿空气的输送以及低层冷空气的持续扩散为暴雪和冻雨的发生提供了很好的温度层结条件。云微物理过程特征分析表明,此次暴雪冻雨过程存在多种云系共同降水,中低空600—850 hpa强逆温层尤其是0 ℃层的存在使得雪、冰晶等冰相粒子融化形成过冷却水,是大范围冻雨形成的必要条件,同时也是区分大范围冻雨暴雪形成的重要条件。 相似文献
8.
南方不同类型冰冻天气的大气层结和云物理特征研究 总被引：4，自引：0，他引：4
利用观测资料和CAMS中尺度云分辨模式,对南方3次不同类型冻雨天气过程进行模拟,重点研究了冰冻天气中冻雨区云系宏、微观结构及大气层结特征,初步分析了冻雨形成的云物理机制.结果表明:(1)逆温层的存在是冻雨发生的必要条件,低层湿度较大的逆温常与冻雨天气有关.3次冻雨过程的冻雨区都存在逆温层,其中第一、二次过程属于锋面逆温,而第三次过程属于平流逆温.可见,逆温层结有利于冻雨的发生,但逆温层的存在仅是形成冻雨的条件之一.冻雨的发生还与水汽(湿度)、风向风速、地面特征有关.低层有水汽输入到冻雨区、地面温度等于或低于0℃,有利于冻雨形成和过冷雨水的冻结.(2)冻雨的形成需要满足3个主要条件:在对流层中高层存在冻结层,冻结层下要有暖层和逆温层,近地层有一个温度＜0℃的冷却层,并且低层的冷却层相对湿度较高.中高层冻结层主要产生冰相降水粒子,中层的暖层可以确保上层降落下来的固态降水粒子(雪或霰)融化成雨滴或在融化层中直接产生液态降水.这样,雨滴下降到低空冷却层后会逐渐变成过冷雨滴,当过冷却雨滴接触到＜0℃的地面或者其他物体表面时,迅速冻结形成冻雨.(3)不同冻雨区上空存在2种不同类型的云,对应云中有2种明显不同的温度层结:混合相云中的“冷-暖-冷”层结和水云中的“暖-冷”层结.具有2种不同层结特征的不同冻雨区云系,对应2种不同的微物理结构,具有2种不同的冻雨形成的云物理机制.(4)同一类型天气系统中的冻雨区,可以存在不同的温度层结、云的微物理结构和冻雨形成的机制;不同类型天气系统也可以存在特征相同的冻雨区,即冻雨形成的温度层结、云的微物理结构和冻雨形成的物理机制都相同. 相似文献
9.
利用多普勒雷达资料、FY-2E静止卫星和MODIS极轨卫星反演产品,研究2012年7月21日北京特大暴雨的云降水结构及云雨转化特征。结果表明:降水过程三阶段的云降水垂直结构不同。1)在暖区对流降水阶段,降水以暖雨机制启动,雨滴在暖区存在深厚的碰并增长过程,暖雨过程对降水起主要贡献。随着云体的发展,冷雨过程加剧。T-Re分析表明,-10℃层以下云滴凝结碰并显著,-10℃层以上为深厚的冰相增长带,云顶以冰相大粒子为主,云水向雨水转化迅速。2)在锋面对流降水阶段,降水系统为高度组织化的"低质心"强降水液态MCC(Mesoscale Convective Complex)系统。回波强度在冰水混合层增长较快,冻结层是此阶段成雨微物理的关键层。降水粒子在暖云区碰并增长较快,而蒸发或破碎过程并不显著。3)在锋后降水阶段,0℃层附近冰晶粒子与云水的碰并增长较为明显。前期降水存在明显的雨滴蒸发过程。随着云体的发展,暖区云水含量较少,降水粒子不能有效碰并增长。 相似文献
10.
西北地区一次层状云降水云物理结构和云微物理过程的数值模拟研究 总被引：6，自引：3，他引：3
利用MM5中增加的双参数显式云物理方案模拟了西北地区一次层状云降水过程,模拟结果显示对小雨的预报评分较高,对中雨以上评分低而且位置有一定偏差,即对层状云降水模拟效果较好。模式中增加了雷达反射率的计算,与延安站雷达RHI回波相比较,模拟的回波结构基本符合层状云回波特征,存在0℃层亮带。采用三层模型解释模拟的层状云降水形成机制和过程:第一层为冰晶区,无过冷水;第二层存在过冷水,为各种冰相粒子增长区,第一层和第二层的分界不固定;第三层和第二层的分界在0℃,为暖云。第一层对第二层播种冰晶,第二层为第一层播种下的冰晶供给过冷水,使冰晶快速增长;第二层对第三层播种雪和霰,使其在第三层融化成雨,第三层同时消耗云水。模拟给出了三层模型层状云场的空间结构,延安站不同时刻微物理量垂直分布和各种水凝物粒子的生成源项分析揭示了三层模型降水形成机制和主要微物理过程。三层模型可以完整和全面地解释层状云降水形成机制和过程。 相似文献
11.
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. 相似文献
12.
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. 相似文献
13.
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. 相似文献
14.
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. 相似文献
15.
Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei Lü Yang SUN Tao SONG Wendell W. WALTERS Xuejun LIU Nicholas A. MARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 《大气科学进展》2020,37(9):933-938
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 相似文献
16.
《大气和海洋科学快报》2013,(1):67
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 相似文献
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18.
<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. 相似文献
19.
《大气和海洋科学快报》2014,7(6):F0003-F0003
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. 相似文献
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. 相似文献
20.
《大气和海洋科学快报》2014,(5):F0003-F0003
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. 相似文献