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1.
甘肃庆阳市雾的气候特点及其预报思路初探 总被引：1，自引：0，他引：1
通过统计甘肃庆阳市1971～2003年的历史资料，分析了庆阳市雾的气候特征：庆阳市年均雾日最大值出现在西峰、合水一带，雾日以秋季9月、10月和春季3月出现较多，夏季、冬季和春季4月、5月较少。对2000～2003年出现的101次雾天气条件做了分析，就形成雾的原因和环流特征做了初步探讨，并归纳提出了庆阳市雾预报的着眼点和一般的预报思路，辐射雾和平流雾分别对应两种截然相反的天气条件，要根据形成雾的天气系统环流典型场采取不同的预报思路，着重分析天气系统的演变，还要分析本地湿度、温度和风向风速等气象要素场的变化特征。 相似文献
2.
2011年3月15日～18日是一次典型的南支槽与强冷空气相结合的天气过程,此次过程对云南省造成了强降温雨雪天气.为了研究此次天气过程的成因以及为今后类似天气过程提供预报思路,利用6h间隔的NECP 1°×1°再分析资料、常规观测资料和TBB黑体亮温资料,对此次天气过程进行天气学分析和诊断分析.分析结果表明:500hPa高度上中高纬度呈横槽型,横槽与高原东侧的低槽连接,槽后强劲的西北气流为这次寒潮天气过程带来强冷平流;南支槽的东移并加强使暖湿气流不断向云南境内输送;高低层冷暖气流交汇,低层切变线、地面冷锋的持续作用触发了此次降温雨雪天气. 相似文献
3.
2011年3月15日～18日是一次典型的南支槽与强冷空气相结合的天气过程,此次过程对云南省造成了强降温雨雪天气.为了研究此次天气过程的成因以及为今后类似天气过程提供预报思路,利用6h间隔的NECP1°×1°再分析资料、常规观测资料和TBB黑体亮温资料,对此次天气过程进行天气学分析和诊断分析.分析结果表明:500hPa高度上中高纬度呈横槽型,横槽与高原东侧的低槽连接,槽后强劲的西北气流为这次寒潮天气过程带来强冷平流;南支槽的东移并加强使暖湿气流不断向云南境内输送;高低层冷暖气流交汇,低层切变线、地面冷锋的持续作用触发了此次降温雨雪天气. 相似文献
4.
针对风廓线雷达资料分辨率高但目前业务应用不广泛的问题,通过对2006年6月29日一次因飑线天气引发的强降水的观测,分析水平风场、垂直气流和大气虚温的变化,以及高低空急流出现的时机并结合地面观测实况,探讨风廓线雷达资料在此类天气过程中的应用.结果表明,水平风场可以清晰地显示高空急流和低空急流出现的时刻和高度,高空急流区和低空急流区不断发展并相互靠近可以预示阵风锋的到来;垂直速度正值突然增大(气流向上为正,向下为负)并迅速变成负值是判断阵风锋过境的一个依据,同时也预示降水即将开始;另外,高空温度递减率的突然加大对降雨的出现也有一定的预示作用. 相似文献
5.
针对风廓线雷达资料分辨率高但目前业务应用不广泛的问题,通过对2006年6月29日一次因飑线天气引发的强降水的观测,分析水平风场、垂直气流和大气虚温的变化,以及高低空急流出现的时机并结合地面观测实况,探讨风廓线雷达资料在此类天气过程中的应用.结果表明,水平风场可以清晰地显示高空急流和低空急流出现的时刻和高度,高空急流区和低空急流区不断发展并相互靠近可以预示阵风锋的到来;垂直速度正值突然增大(气流向上为正,向下为负)并迅速变成负值是判断阵风锋过境的一个依据,同时也预示降水即将开始;另外,高空温度递减率的突然加大对降雨的出现也有一定的预示作用. 相似文献
6.
卫星热遥感技术在地震预测中应用研究进展 总被引：6，自引：3，他引：3
已有的研究结果表明。许多强地震前存在热异常。异常的表现形式是多种多样的，异常的时空分布与异常区的地质构造、地理环境、季节、天气等因素有关。内陆地区的地震前常产生热红外异常，而沿海地区的地震前则更容易出现潜热通量异常。红外辐射可以通过卫星红外通道的传感器观测到。而潜热通量可以使用微波遥感观测资料计算或红外遥感与地面观测资料联合反演。应用卫星遥感技术研究地震前的热异常虽然目前仍然存在许多问题，但随着技术的进步和研究工作的深入，应该能在地震预测中发挥重要作用。 相似文献
7.
龙思维 《成都信息工程学院学报》2014,(Z1):161-165
利用三亚凤凰机场实时观测数据、常规地面观测资料、高空观测资料、三亚地区多普勒雷达资料及闪电定位资料,从天气形势、物理机制、雷达回波和闪电特征等方面对2012年4月21日的飚线天气过程进行了详细分析。结果表明:地面冷锋、低涡切变线以及高空槽相互配合是产生此次强对流天气的天气尺度系统,飑线是此次对流天气的直接影响系统;欧阳位温图和雷雨顺能量图对此次强对流飚线过境有一定的指示意义;多普勒雷达图和闪电定位资料在临近预报中能够有效识别飚线特征,对飚线的移动方向、维持时间的预报有指导意义。 相似文献
8.
余燕群 《成都信息工程学院学报》2013,(5):549-556
对2012年8月19～21日西藏持续性强降水天气过程的成因进行分析。利用加密地面观测资料、FY一2C卫星TBB资料、常规观测资料和NCEP 1°×1°再分析资料,对2012年8月19--21日西藏持续性强降水天气过程进行诊断和中尺度特征分析。此次强降水天气过程是在稳定的径向型环流背景下产生的,巴尔喀什湖附近东移南下的短波槽和500hPa低涡切变是造成此次降水过程的主要影响系统,西太平洋副热带高压边缘的西南暖湿气流为降水过程提供r有利的水汽条件;β中尺度对流云团的先后影响,为强对流发展提供了必要的热力、动力条件;而中层冷空气的侵入和强的垂直风切变加剧了大气层结的不稳定,为降水天气提供了有利的条件。该研究为西藏夏季降水的相关预报预测提供科学依据。 相似文献
9.
《成都信息工程学院学报》1986,(2)
我国在1985年首次南极综合考察期间,气象工作者在长城站进行了地面气象要素、高空风、辐射、卫星云图接收、雷达回波分析、大气化学成份和气溶胶采样分析等综合性观测和分析。所获资料虽然最长仅一年,但这是我国气象工作者第一次获得由我们搜集到的第一手的南极气象情报,来之不易,极为宝贵。经气象考察人员的初步分析和研究,已撰写了内容包括:“南极地区天气和水文分析预报”“气象要素变化特征”“大气结构及辐射状况” 相似文献
10.
结合气象观测和大气边界层探测资料，分析了１９９０年１月２日重庆雾的声雷达回波特征，并与１９８９年１２月３０日雾的回波作了比较。结果表明，雾顶回波高度与逆温和相对湿度的转折高度一致；雾顶回波在雾的成熟期呈现波动，在消散期有一下降过程。上午大气污染物地面浓度的变化与逆温混合层状况有密切关系，混合层较薄且持续时间较长时，地面浓度较大 相似文献
11.
In this paper, a heavy sea fog event occurring over the Yellow Sea on 11 April 2004 was investigated based upon observational and modeling analyses. From the observational analyses, this sea fog event is a typical advection cooling case. Sea surface temperature(SST) and specific humidity(SH) show strong gradients from south to north, in which warm water is located in the south and consequently, moisture is larger in the south than in the north due to evaporation processes. After fog formation, evaporation process provides more moisture into the air and further contributes to fog evolution. The sea fog event was reproduced by the Regional Atmospheric Modeling System(RAMS) reasonably. The roles of important physical processes such as radiation, turbulence as well as atmospheric stratification in sea fog’s structure and its formation mechanisms were analyzed using the model results. The roles of long wave radiation cooling, turbulence as well as atmospheric stratification were analyzed based on the modeling results. It is found that the long wave radiative cooling at the fog top plays an important role in cooling down the fog layer through turbulence mixing. The fog top cooling can overpower warming from the surface. Sea fog develops upward with the aid of turbulence. The buoyancy term, i.e., the unstable layer, contributes to the generation of TKE in the fog region. However, the temperature inversion layer prevents fog from growing upward. 相似文献
12.
In this paper, almost all available observational data and the latest 6.0 version of Regional Atmospheric Modeling System (RAMS) model were employed to investigate a heavy sea fog event occurring over the Yellow Sea from 2 to 5 May 2009. The evolutionary process of this event was documented by using Multifunctional Transport Satellites-1 (MTSAT-1) visible satellite imagery. The synoptic situation, sounding profiles at two selected stations were analyzed. The difference between the air temperature and sea surface temperature during the sea fog event over the entire sea region was also analyzed. In order to better understand this event, an RAMS modeling with a 15 km×15 km resolution was performed. The model successfully reproduced the main characteristics of this sea fog event. The simulated height of fog top and the area of lower atmospheric visibility derived from the RAMS modeling results showed good agreement with the sea fog area identified from the satellite imagery. Examinations of both observational data and RAMS modeling results suggested that advection cooling seemed to play an important role in the formation of this sea fog event. 相似文献
13.
Role of sea ice in air-sea exchange and its relation to sea fog 总被引：1，自引：0，他引：1
Synchronous or quasi-synchronous stereoscopic sea-ice-air comprehensive observation was conducted during the First China Arctic Expedition in summer of 1999. Based on these data, the role of sea ice in sea-air exchange was studied. The study shows that the kinds, distribution and thickness of sea ice and their variation significantly influence the air-sea heat exchange. In floating ice area, the heat momentum transferred from ocean to atmosphere is in form of latent heat; latent heat flux is closely related to floating ice concentration; if floating ice is less, the heat flux would be larger. Latent heat flux is about 21 23.6 W*m-2, which is greater than sensible heat flux. On ice field or giant floating ice, heat momentum transferred from atmosphere to sea ice or snow surface is in form of sensible heat. In the floating ice area or polynya, sea-air exchange is the most active, and also the most sensible for climate. Also this area is the most important condition for the creation of Arctic vapor fog. The heat exchange of a large-scale vapor fog process of about 500000 km2 on Aug. 21 22,1999 was calculated; the heat momentum transferred from ocean to air was about 14.8×109 kW. There are various kinds of sea fog, radiation fog, vapor fog and advection fog, forming in the Arctic Ocean in summer. One important cause is the existence of sea ice and its resultant complexity of both underlying surface and sea-air exchange. 相似文献
14.
在考查了成都双流机场实际天气现象以及雾的多极变化的基础上，提出了奇点雾的概念，并从理论上分析了其发生的物理机制，认为弱冷平流是其发生的主要原因，并提出了预报方法。 相似文献
15.
Fog has recently become a frequent high-impact weather phenomenon along the coastal regions of North China. Accurate fog forecasting remains challenging due to limited understanding of the predictability and mechanism of fog formation associated with synoptic-scale circulation. One frequent synoptic pattern of fog formation in this area is associated with cold front passage(cold-front synoptic pattern, CFSP). This paper explored the predictability of a typical CFSP fog event from the perspective of analyzing key characteristics of synoptic-scale circulation determining fog forecasting performance and the possible mechanism. The event was ensemble forecasted with the Weather Research and Forecasting model. Two groups of ensemble members with good and bad forecasting performance were selected and composited. Results showed that the predictability of this case was largely determined by the simulated strengths of the cold-front circulation(i.e., trough and ridge and the associated surface high). The bad-performing members tended to have a weaker ridge behind a stronger trough, and associated higher pressure over land and a weaker surface high over the sea, leading to an adverse impact on strength and direction of steering flows that inhibit warm moist advection and enhance cold dry advection transported to the focus region. Associated with this cold dry advection, adverse synoptic conditions of stratification and moisture for fog formation were produced, consequently causing failure of fog forecasting in the focus region. This study highlights the importance of accurate synoptic-scale information for improved CFSP fog forecasting, and enhances understanding of fog predictability from perspective of synoptic-scale circulation. 相似文献
16.
近50年中国地表净辐射的时空变化特征分析 总被引：1，自引：0，他引：1
基于GIS空间分析技术与Mann-Kendall趋势分析方法,对中国陆地区域699个气象站点1961-2010年逐年、季平均地表净辐射进行时空变化特征分析,结果表明:(1)参数拟合后的FAO Penman修正式对模拟站点逐日地表净辐射的总体精度较高,均方根误差为27.9W.m-2,相关系数为0.85,平均相对误差为0.13;(2)全国近50年站点平均地表净辐射在年、季均呈现出较明显的下降过程,年均降幅为0.74W.m-2.10a-1,不同季节的下降幅度存在差异,夏季降幅最大;(3)逐站点分析显示全国大部分站点(59.8%)年均地表净辐射呈显著下降趋势(0.05),东部趋势变化比西部明显,夏季在地表净辐射年际变化中的贡献最大,华北、华中、华南地区的站点在春夏秋季均呈显著下降趋势。 相似文献
17.
On spatiotemporal characteristics of sea fog occurrence over the Northern Atlantic from 1909 to 2008
In this paper, the International Comprehensive Ocean and Atmosphere Data Set(ICOADS) is utilized to investigate the horizontal distribution of sea fog occurrence frequency over the Northern Atlantic as well as the meteorological and oceanic conditions for sea fog formation. Sea fog over the Northern Atlantic mainly occurs over middle and high latitudes. Sea fog occurrence frequency over the western region of the Northern Atlantic is higher than that over the eastern region. The season for sea fog occurrence over the Northern Atlantic is generally from April to August. When sea fogs occur, the prevailing wind direction in the study area is from southerly to southwesterly and the favorable wind speed is around 8 m s-1. It is most favorable for the formation of sea fogs when sea surface temperature(SST) is 5℃ to 15℃. When SST is higher than 25℃, it is difficult for the air to get saturated, and there is almost no report of sea fog. When sea fogs form, the difference between sea surface temperature and air temperature is mainly-1 to 3℃, and the difference of 0℃ to 2℃ is the most favorable conditions for fog formation. There are two types of sea fogs prevailing in this region: advection cooling fog and advection evaporating fog. 相似文献
18.
In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite imagery of Geostationary Operational Environmental Satellite (GOES)-9, three data sets from station observations at Dandong, Dalian and Qingdao, objectively reanalyzed data of final run analysis (FNL) issued by the National Center for Environmental Prediction (NCEP) and Regional Atmospheric Modeling System (RAMS) results. Synoptic conditions and fog characteristics were analyzed. The fog formed when warm,moist air was advected northwards over the cool water of the Yellow and Bohai Seas, and dissipated when a cold front brought northerly winds and cool, dry air. In order to better understand the fog formation mechanism, a high-resolution RAMS modeling with a 6km×6km grid, initialized and validated by FNL data, was designed. A 48h modeling that started from 12 UTC 26 March 2005reproduced the main characteristics of this sea fog event. The simulated lower visibility area agreed reasonably well with the sea fog region identified from the satellite imagery. Advection cooling effect seemed to play a significant role in the fog formation. 相似文献
19.
Energy balance at the glacier surface is important for understanding the impacts of climate change on glaciers. Here, we analyzed the characteristics of the glacier surface energy fluxes along with their contributions to glacier melt on Bayi Ice Cap in Qilian Mountains by using a point-scale energy balance model. The half-hourly meteorological data from an automatic weather station (AWS) located on the glacier was used to drive the energy balance model. The model simulated results could accurately represent the mass-balance observations from the stake near the weather station during summer 2016. Our results showed the net radiation (86%) played an important role in the surface energy balance, and the contribution of the turbulent heat fluxes (14%) to the energy budget was relatively less important. A distinct behavior of energy balance, as compared to other continental glaciers in China (e.g., two adjacent glaciers Laohugou No. 12 Glacier and Qiyi Glacier), is the fact that a sustained period of positive turbulent latent flux exists on Bayi Ice Cap during August, causing faster melt rate in the month of August. Our study also presented the effect of frequent summer snowfall in slowing down surface melt by changing the surface albedo during the beginning of the melting season. 相似文献
20.
Atmospheric turbulence plays a vital role in the formation and dissipation of fog. However,studies of such turbulence are typically limited to observations with ultrasonic anemometers less than 100 m above ground. Thus,the turbulence characteristics of upper fog layers are poorly known. In this paper,we present 4-layers of data,measured by ultrasonic anemometers on a wind tower about 400 m above the sea surface; we use these data to characterize atmospheric turbulence atop a heavy sea fog. Large differences in turbulence during the sea fog episode were recorded. Results showed that the kinetic energy,momentum flux,and sensible heat flux of turbulence increased rapidly during the onset of fog. After onset,high turbulence was observed within the uppermost fog layer. As long as this turbulence did not exceed a critical threshold,it was crucial to enhancing the cooling rate,and maintaining the fog. Vertical momentum flux and sensible heat flux generated by this turbulence weakened wind speed and decreased air temperature during the fog. Towards the end of the fog episode,the vertical distribution of sensible heat flux reversed,contributing to a downward momentum flux in all upper layers. Spatial and temporal scales of the turbulence eddy were greater before and after the fog,than during the fog episode. Turbulence energy was greatest in upper levels,around 430 m and 450 m above mean sea level(AMSL),than in lower levels of the fog(390 m and 410 m AMSL); turbulence energy peaked along the mean wind direction. Our results show that the status of turbulence was complicated within the fog; turbulence caused fluxes of momentum and sensible heat atop the fog layer,affecting the underlying fog by decreasing or increasing average wind speed,as well as promoting or demoting air temperature stratification. 相似文献