下沉气流

结果表明：雹胚源区出现在主上升气流前侧上升气流向辐散下沉气流的转向处，在垂直方向上位于最大上升速度上方；

The findings show that location of hail embryo lies in front of the main updraft , at the turning of updraft to divergence downdraft , and above the largest ascending velocity in the vertical direction .

在对流层中层（500～660hPa）θe达到其极小值，该高度是风暴云中下沉气流的起始高度。

In addition , there is a θ emin in the middle of troposphere ( 500 ~ 660hPa ), which is the starting level of the downdraft in the storm cloud .

与下沉气流强度、上升气流夹卷率和对流有效位能（CAPE）消耗时间相关的参数能对模式性能造成显著影响。

The model performance is found to be sensitive to downdraft-and entrainment-related parameters and consumption time of Convective Available Potential Energy ( CAPE ) .

下沉气流对Z-I关系的影响

The Effect of Downdrafts on Z - I Relation

通过分析850hPa等压面上的垂直速度场发现秋旱同期长江以南地区下沉气流异常，这种天气形势不利于降水的产生。

The analysis of vertical velocity at 850 hPa indicates the anomaly of the sinking flow during the drought which is not in favor of rain . The subtropical anticyclone controlling the area to south of the Yangtze River in autumn 2004 influences the development of drought .

而倾斜的下沉气流前侧不利于窄带回波的形成。

The front of inclining downdraft is unfavorable to the narrow-band echo .

在此工作基础上，设计了考虑下沉气流的积云参数化方案。

Based on above works , the cumulus parameterized scheme is designed , which includes the downdrafts .

在低层，暴雨区的后部存在着弱下沉气流，并导致了一个相应的低层冷区和地面弱流出辐散气流。

There was a weak downdraft at the rear of the heavy rain region at low level .

受卢碧的外围下沉气流影响，未来数天香港将会天晴并有烟霞。

LUPIT 's subsidence will bring fine and hazy weather to Hong Kong in the next few days .

降水、下沉气流、气流辐合区、冷锋锋面会导致草地螟集中降落。

Precipitation , atmospheric subsidence , air convergence , and cold front will lead convergent landing of meadow moth .

在飓风的中心，干燥的下沉气流创造了一片奇特的平静区域，这就是风眼。

Within the center of the hurricane , downdraughts of dry air create a strangely calm area called the eye .

此次干旱主要受孟加拉湾海温偏高的影响，使得西南地区处于异常下沉气流的控制之下，造成了极端干旱事件的发生。

The drought was mainly affected by the high SSTA in Bengal , which caused the abnormal sinking airflow in Southwest China .

在不同的环境条件下，下沉气流发展的云物理过程可以有较大的差异。

This paper points out that , in different environment conditions , cloud-physics for the evolution of the microburst may be very different .

广州地区的高温天气主要是受副热带高压和台风外围下沉气流的影响所致。

Summer high temperature in Guangzhou is mainly caused by the dominance of the subtropical high and the peripheral subsidence airflow of typhoon systems .

绿洲的水汽输送通过地形下沉气流加强，使山谷绿洲的气候效应得到加强。

The water vapour transport in oasis is enhanced through downdraft in terrain , making the climatic effect in oasis of mountain valley to enhance as well .

在副高北侧东亚副热带季风雨带上有暴雨发生时，其凝结海热激发的经圈环流对相应经度上的副高脊线附近的下沉气流有显著贡献。

When rainstorms happen in the rainband of East Asian subtropical monsoon on the STH north side , the downdrafts are distinct around the ridge at a related meridian .

应用定常的二维模式作数值模拟，结果表明：大尺度地形可影响到山脊上游的大气运动，山脊上游出现下沉气流，造成干燥气候；

Results from numerical simulation show : ( 1 ) large-scale orograph may produce subsidence of air flow upstream of the mountain ridge , thus resulting in dry climate ;

城市热岛的存在导致局地上升运动，热岛发展强烈的区域上空存在明显的上升气流，下风附近则对应着下沉气流，形成热岛环流。

The UHI induces local ascending motion . The obvious upward flows exist over the UHI areas , and downward flows over the leeward , forming the heat island circulation .

从对流单体降落的冷凝物的水平宽度比观测到的做尺度下沉气流的宽度小得多（前者60公里而后者150公里）。

The horizontal width of the condensate falling from the convective cells was much less than the width of the observed mesoscale downdraft ( 60 km compared to150 km ) .

结果表明：模拟的上升气流对雨强测量的影响大于下沉气流，垂直气流速率越大雨强测量误差愈显著；

The main results were obtained that : ( 1 ) The measured error on rain rate caused by the updraft is larger than that by the downdraft in the vertical direction .

它表现为在绿洲区域比戈壁沙漠区域环境温度低、湿度大、湍流动能输送弱，具有下沉气流而导致与周围戈壁沙漠区域产生水平输送环流。

It displays that environmental temperature is lower , humidity is higher and the energy of turbulent momentum transfers weakly over oasis than over desert , and there are circulations between oasis and desert .

在条件不稳定大气中，一支强湿上升气流的形成是很容易理解的，但一支湿下沉气流的发生则比较复杂。

It is easier to understand the formation of the strong updraft in the case of an unstable stratification but it is more complex in describing the process of the downdraft inside the cloud .

但是必须注意到，这种方法存在滤波发散的风险。并且在实际应用中，对流性降水产生的剧烈上升、下沉气流使得风场信息表现为非线性。

But it must be noted that , this approach has the risk of filter divergence and in the practical application , the updraft and downdraft producing from convective precipitation makes wind fields exhibiting nonlinear .

迁出种群大部分向东北方向迁飞，途经丰宁等地时发生了迫降，迫降是由强下沉气流引发的。（3）归纳了草地螟起飞、降落、远距离迁飞的天气背景。

Most of the emigrating population flew northeast and landed involuntarily in Fengning County due to the atmospheric subsidence . ( 3 ) The weather background for taking-off , landing , and long-distance migration of meadow moth are summarized .

结果表明，造成气温持续偏高和破历史极值的主要原因是：在稳定的环流形势下，伊朗高原的暖气团北上东移，暖平流输送辐散下沉气流增温。

The result shows that under stable circulation , the movement of Iran Plateau air mass toward northeast and the thermal advection and directive down flow are the main causes of the persistant warm weather and the high temperature record .

整层出现辐合上升运动，且强上升速度中心的高度随时间的演变逐渐下降，同时中高层出现强辐散下沉气流与之配合时，未来2小时将出现强降雪；

If anabatic movement appears in whole lower layer and the height of the strong updraft center is lower and lower along with time accompanying with strong downdraft in middle-high layers , then heavy snowstorm will appear in 2 hours later there .

大陆热低压西边的高纬风使对流层中、下层出现下沉辐散气流，是副热带旱区干旱的根本原因；

The sinking divergence air current resulted from high-latitude wind in the west to continental thermal depression is the ultimate cause to form subtropical arid region .