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1.
通过对洛阳地区11次强对流天气进行分析,发现强对流天气分两类,并分别和不同的中尺度系统相联系.两类强对流天气发生在不同的大尺度环境场中,不仅环流形势不同,环境特征也有明显差异,因而对他们的预报思路和着眼点也应区别对待. 相似文献
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吉林省对流性天气的分布特征及地形影响机制 总被引:1,自引:1,他引:1
通过对吉林省强对流天气和对流性天气活动与地形关系的分析,初步揭示出地形对两类对流天气的影响机制,其结果对进一步分析研究和准确预报强对流天气具有重要意义。 相似文献
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2001年河南两次强对流天气过程对比分析 总被引:4,自引:0,他引:4
对2001年连续两次发生在河南省的以冰雹和雷雨大风等强对流天气为主的过程对比分析结果表明,在不同的天气背景下,强对流过程中的中尺度雷达回波系统不同,对应的灾害性天气的各类和影响范围也不相同。 相似文献
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对2001年连续两次发生在河南省的以冰雹和雷雨大风等强对流天气为主的过程对比分析结果表明,在不同的天气背景下,强对流过程中的中尺度雷达回波系统不同,对应的灾害性天气的种类和影响范围也不相同. 相似文献
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根据广西强对流天气的普查和统计分析,将全区日出现雷雨大风、冰雹总站次≥5的作为区域性的强对流天气过程。通过对1990~2001年共12a春季(2~5月)广西所出现的51次区域性强对流过程的环流形势场和对强对流天气有指示意义的一些物理量场的合成分析,得出了广西产生区域性强对流天气过程的环流特征和物理量的分布演变特征。 相似文献
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相同大尺度环流背景下不同类型强对流天气个例分析 总被引:1,自引:0,他引:1
利用常规观测、雷达、卫星和自动站等资料,对2013年3月23日广西一次区域性强对流天气过程中两种不同类型强对流天气现象产生的局地环境条件、触发机制及中尺度等特征进行了对比分析。结果表明:在相同大尺度环流背景下,两种类型强对流天气(即干对流型和混合对流型)在大气层结、湿层厚度、对流有效位能(CAPE值)和垂直风切变等局地环境上存在一定差异;其触发机制不同,广西西部干对流由位于地面锋前暖区的辐合线触发,而北部混合型强对流则由地面锋面触发;雷达和卫星图像上,两类强对流在形态、强度和移速上均存在明显差异,这些差异对广西不同类型强对流天气的监测预警具有一定的参考价值。 相似文献
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利用常规气象资料,对榆林2013年8月4日(简称"8·4过程")和2017年7月23日(简称"7·23过程")两次不同类型的极端强对流天气综合分析,通过比较环境参量,将两类强对流天气分为混合型强对流("8·4过程")和强降水型强对流("7·23过程")天气,并给出两类强对流天气不同参量的预报参考阈值。结果表明:(1)地面温度T、地面露点温度Td、比湿q、水汽通量散度等环境参量反映了天气区高温高湿的特性;对流有效位能CAPE、假相当位温θse、T850-500、θse850-500、T-Td等环境参量反映了不稳定条件;850~500hPa垂直风切变和地面风速等环境参量反映对流触发和抬升力。(2)主要参量的参考阈值:混合型强对流天气,T850-500≥28℃,(T-Td)700≥22℃,地面风速≥4m/s;强降水型强对流天气,θse850≥87℃,q850≥17g/kg,地面温度T≥32℃。 相似文献
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通过对2006年5月3日和7月17日库尔勒地区两次强对流天气的形势和物理量对比分析,以及库尔勒新一代天气雷达(CINRAD—CC)产品中的组合反射率(CR)、风暴相对平均径向速度(V)等产品的分析,得出库尔勒地区夏季强对流天气过程发生时的有利天气形势、物理量场分布及多谱勒天气雷达产品特征。 相似文献
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2003年河南省两类典型暴雪天气对比分析 总被引:6,自引:0,他引:6
通过对2003年2月9~10日和3月4~5日河南省出现的两场区域性暴雪的环流背景、成因特征、物理量的对比分析,得出了低层切变线上气旋性曲率东扩或低涡东移是产生暴雪重要原因的结论;并给出了这两种不同类型暴雪天气的预报着眼点。 相似文献
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作为初值问题的天气形势数值预报与由地面天气历史演变作预报的等值性 总被引:15,自引:3,他引:15
天气数值预报研究中对预报问题的提法与日常天气预报工作中由天气历史演变来作预报的那种提法是很不相同的.本文对大尺度运动讨论了这两种提法在一定的简单附加条件下是等值的.由此也说明地面温压场的演变反映了也蕴含了斜压大气三维温压场的构造,并且决定了斜压大气三维温压场的发展. 相似文献
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卫星云图在预报哈尔滨春季沙尘天气中的应用 总被引:1,自引:0,他引:1
利用卫星图像资料与常规探测资料,分析2000-2007年春季哈尔滨飞行区域的沙尘天气,结果发现:造成沙尘天气的蒙古气旋可分为高、低压同时发展型和强低压发展型;大风和对流层底层大气的湍流运动是造成沙尘的主要因素。 相似文献
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在混炖的Lorenz系统中,相点坐标x与y之间的符号关系决定相点能否通过y-z面,从而决定了相点在吸引子的哪一“翼”中运动。通过在一定位置对y施加微小的影响,使系统未来发展方向只剩下一种可能性,系统便成为周期性的,并且通过选择对y实施影响的位置,可以选择系统的周期性运动的方式,从而达到对Lorenz混沌的控制,这就说明内在随机性这一对预测不利的因素,却为对Lorenz混饨的人为控制提供了有利的时机。 相似文献
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利用辽宁自动气象站逐小时降水资料和1。X1。NCEP资料,对200l-2010年汛期共25次辽宁暴雨过程进行分析,以期得到暴雨过程时间分布特征和典型影响系统。结果表明:25次辽宁暴雨过程中有7次为阶段性暴雨即两段持续性暴雨过程中间有明显的降水减弱与天气系统转换,占总数的28%;辽宁暴雨过程高层(以200hPa为代表)主要影响系统为高空急漉,中层(以500hPa为代表)主要影响系统92%为高空槽(其中57%为高空槽与副热带高压共同影响),低层(以850hPa为代表)诱发系统88%为气旋(或倒槽)顶部(或东部)切变线、12%为鞍形场切变。阶段性暴雨过程两阶段的高中层影响系统基本一致,高层影响系统均为高空急流,中层多为副热带高压和高空槽的共同影响、少数仅受高空槽影响,在低层,阶段性暴雨过程均伴随着低层要素场(特别是风场)的调整,导致低层天气系统的转换或强度的变化,低层要素场的调整阶段即为阶段性强降水的间歇期;阶段性暴雨过程在天气系统的配置及时段长度方面无明显特征,即在暴雨过程发生初期,从这两方面均无法判断该暴雨过程是否将发展为阶段性暴雨。25次辽宁暴雨过程中,丹东本溪地区17次降水有陡增现象,这与丹东、本溪地区处于长白山东南部和丹东地区东南侧临海有密切关系。 相似文献
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Sensitivity analysis of 18 different potential evapotranspiration models to observed climatic change at German climate stations 总被引:3,自引:0,他引:3
Helge Bormann 《Climatic change》2011,104(3-4):729-753
Potential evapotranspiration models very often are important part of hydrological catchment models to calculate potential evapotranspiration (PET) which then is used to estimate actual evapotranspiration considering the soil moisture status. As many different approaches exist, the question arises in which way the choice of the PET model affects the impact of climate change on the calculated water balance? Therefore, 18 different PET models were compared with respect to their sensitivity to observed climate change. Long-term climate data of six German climate stations were used to identify changes in the climate data itself and changes in the calculated PET. The results show that all investigated PET models are sensitive to significant trends in climate data. However, it is also shown that all models show different sensitivities, and that the sensitivities cannot be grouped in terms of different types of PET models such as the aerodynamic concept, radiation or temperature based approaches and combination equations. Predominantly, the variability within a group of models of the same type is comparable to the variability between different model types. Therefore it can be concluded that PET models should be validated in a regional context before they are applied to a certain region within a climate change study despite the poor availability of long-term PET measurements. 相似文献
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One of the central questions in climate change debates concerns fair burden-sharing, i.e. justice in the distribution of costs of undertaking climate-managing policies. In this paper it is argued that in order to distribute such costs justly, it is necessary to have a nuanced understanding of what types of burdens they represent. Climate managing policies are usually divided into responses that seek to reduce the concentration of greenhouse gases in the atmosphere (mitigation) and responses that seek to prevent harm arising from a changing climate (adaptation). Some have argued that there are normatively significant differences between mitigation and adaptation: that the two responses adhere to different logics and evoke different patterns of burden-sharing. This paper argues that the relevant distinction is instead between negative and positive climate duties, i.e. whether an agent has a duty to undertake climate-managing policies on account of the harm its excessive emissions are causing or simply on account of its ability to assist those in need. The paper offers a typology of the different mitigation and adaptation responses that can be sorted under the negative/positive distinctions. This way of conceptualizing the issue not only enables us to better address the burden-sharing question, offering a more nuanced understanding of the types of climate burdens that are ascribable to agents and pointing out the appropriate roles of contributory responsibility and ability. It also clarifies aspects of the climate negotiations, and explains why it matters whether adaptation finance transferred to vulnerable countries is portrayed as compensation for harmful emissions or simply as donor countries discharging their humanitarian duties. 相似文献
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Vertical cumulus momentum transport is an important physical process in the tropical atmosphere and plays
a key role in the evolution of the tropical atmospheric system. This paper focuses on the impact of the vertical
cumulus momentum transport on Madden-Julian Oscillation (MJO) simulation in two global climate models (GCMs). The
Tiedtke cumulus parameterization scheme is applied to both GCMs [CAM2 and Spectral Atmospheric general circulation
Model of LASG/IAP (SAMIL)]. It is found that the MJO simulation
ability might be influenced by the vertical cumulus momentum transport through the cumulus parameterization scheme.
However, the use of vertical momentum transport in different models provides different results. In order to improve
model's MJO simulation ability, we must introduce vertical cumulus momentum transport in a more reasonable way into
models. Furthermore, the coherence of the parameterization and the underlying model also need to be considered. 相似文献