共查询到19条相似文献，搜索用时 125 毫秒
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黄、渤海表层海温对台风过程响应数值试验 总被引：4，自引：0，他引：4
根据黄、渤海夏季由台风引起的异常海温的主要特点 ,构造一个简单而典型的台风过程模型 ,利用“近海异常海温数值预报模式”对海表层温度进行了数值试验 ,对台风过程中引起异常海温的各因子进行了定量分析 ,给出台风中心及其附近各点由各因子引起的变温率变化。试验表明 ,在台风作用下 ,冷水抽吸是引起异常低温的主要原因 ,大风夹卷的贡献占第二位 ,蒸发潜热的作用也不容忽视。数值模拟还清晰地显示出台风所引起的左弱右强的不对称降温效应以及表层暖水向外输运并在台风边缘下沉的现象。另外 ,还对近海异常海温预报模式的几个关键性问题及模式需改进之处进行了讨论。 相似文献
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利用非静力中尺度数值模式 WRF (V2.2)对0518号台风“达维”(Damrey)经过海南岛过程进行了模拟.模式较好地再现了“达维”经过岛屿过程的移动路径、强度变化、环流结构以及降水分布.基于模拟结果,分析了台风内核区的动、热力场演变特征,结果如下:1)经过岛屿期间,台风内核区高、低层切向风速变化不大,贴地层与中间层切向风速在登陆过程及岛上移动前期减小,岛上移动后期到离岛入海期间增大.2)台风内核区高、低层分别存在主体出流及回流入流、主体入流及回流出流.登陆过程及岛上移动前期,主体入流速度变化不大,主体出流明显减弱.岛上移动后期到离岛入海期间,主体出流与回流出流明显加大并出现合并趋势.3)经过岛屿期间,台风环流区的环境风垂直切变没有像大多数热带气旋登陆一样出现增大的趋势,反而减小.切变下风方向先顺转后逆转,切变下风方向左侧与降水区有较好对应.4)登陆过程及岛上移动前期,台风高、低层的垂直速度及凝结加热均显著减小;岛上移动后期,高层垂直运动及凝结潜热释放继续减小,低层则明显增大. 相似文献
3.
台风"森拉克"的数值模拟研究:海洋飞沫的作用 总被引：7，自引：0，他引：7
台风作为一种在海洋上生成和演变的强烈天气现象，除了环境流场、自身结构以及地形等因子对它产生影响外，海气间的热量动量交换也是台风演变过程中不可或缺的因子。台风期间在海气界面生成大量海洋飞沫，这些飞沫在台风边界层的蒸发必然对海气之间的通量传输过程产生影响，进而影响到台风本身的演变。文章将海洋飞沫参数化引入大气中尺度模式中，对2002年16号台风“森拉克”的演变进行了数值模拟研究。结果表明，引入海洋飞沫参数化方案，可使台风期间海气界面的潜热通量增加50％，10m层风速最大值增加30％，从而使模拟台风的强度明显增加，使模拟结果更趋于合理。因此，在台风数值模拟和预报中考虑海洋飞沫的作用是十分必要的。 相似文献
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利用1°×1°NCEP再分析资料、卫星云图和中尺度自动站等气象资料,分析了环流背景对台风莫拉菲的路径和降水变化的影响,并对莫拉菲的降水过程的物理量特征进行诊断分析.结果表明,500 hPa副热带高压带状分布,副高南缘偏东气流加强,台风北侧最大东风风速与南侧最大西风风速之差增大是造成台风路径变化并稳定向西北偏西方向移动的主要原因;莫拉菲在向西北偏西方向移动过程中,其水汽通量相对散度、垂直速度、涡度等各物理量场均表现出有利于强降水出现的特征,也揭示了此次台风造成的强降水出现地区性差异的主要原因. 相似文献
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2015年4月2日,中国海洋大学东方红2船在东海黑潮暖水区观测到了一次夜间云顶逆温边界层发展的过程。本文利用船载数据及UCLA_LES3.0模式进行数值模拟,讨论边界层发展的原因以及云对边界层发展的作用。结果显示,海表潜热通量的供应使边界层内水汽增多,水汽抬升凝结成云。云的产生使边界层内水汽通量、热通量以及垂向湍流速度的分布发生改变,云区的水汽通量变大,云顶的热通量发生突变,云区和近表面层均有湍流速度的极大值,云底有湍流速度的极小值。云形成过程中通过改变边界层内浮力项的贡献影响边界层的垂直结构,云区有正的浮力项贡献,云底以下有负的浮力项贡献。云顶长波辐射主要影响边界层中上层,在关闭辐射强迫后,边界层内比湿和位温的廓线没有明显变化,但最大垂直速度减小了20%,垂向积分的湍流动能降低了约30%,垂向湍流速度在边界层中上层不存在极大值,边界层内热通量廓线没有突变,水汽通量和热通量廓线分布与晴空边界层廓线相当。本研究通过数值试验证明了云顶长波辐射效应对大气边界层的反馈作用,为理解云与边界层的相互作用提供了科学依据。 相似文献
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台风"卡努"(0515)加强过程对边界层参数化方案的敏感性试验 总被引：2，自引：0，他引：2
利用中尺度非静力MM5模式，分别选用Eta、Blackdar和MRF3种边界层参数化方案，对台风“卡努”（0515）登陆前加强过程进行数值模拟，模拟结果对比分析及其与实况的比较表明：边界层方案对台风强度有明显影响，“卡努”个例试验中Eta方案模拟的台风强度较好，Blackdar方案次之，而MRF方案较差．边界层通量分析表明这种差别主要是由水汽凝结潜热释放多寡造成的．边界层方案的差异也导致台风动力和热力结构在水平和垂直分布上都出现显著差异． 相似文献
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为了使台风路径的数值预报更加精确,本文对人造(Bogus)涡旋构建方案进行了改进,形成了一种新的Bogus方案.该方案直接采用台风外围的风圈观测信息,并成功地植入到WRF(weather research and forecasting)模式中.本文利用该方案,选取2011年9号台风"梅花"这一典型案例展开讨论,结果表明:1)新构造的台风切向风廓线更加真实地反映了台风风场的实际情况;2)新的Bogus方案对台风中心位置的预报,更有利于对台风路径的预报;3)台风内核风场强度,对其非对称结构起到关键的作用,直接影响对台风路径的预报. 相似文献
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南海北部一次台风浪过程的数值模拟 总被引：1，自引：1，他引：0
采用Holland 模型将2009 年6 号台风莫拉菲参数化, 并通过一个权重系数将模型风场和背景风场叠加起来, 构造了南海北部台风过境时的风场。随后通过时空插值, 将该风场以空间分辨率5′×5′、时间步长1 h 的精度输入到SWAN(Simulating Waves Nearshore)模式中, 模拟了莫拉菲台风通过时南海北部的海浪场。然后使用Jason-2 卫星波高数据对模式进行了验证, 结果表明模式结果与实测值吻合良好。利用模式结果我们分析了台风中心和海浪场的最大有效波高中心的位置关系, 以及台风风场结构和海浪场结构的关系。最后, 通过计算海浪场的能量并将其与风要素和浪要素对比, 我们研究了台风过境期间海浪场的动力机制。 相似文献
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台风暴雨灾害是台风三类灾害(暴雨、大风、风暴潮)之首,而台风极端降水是暴雨灾害的直接原因,对台风极端降水的研究有利于增强对台风极端降水机理的认识和提高极端降水的预报水平。强台风“菲特”(1323)具有登陆强度历史罕见、降雨强度大、影响范围广、引发灾害重等特点,本文对“菲特”极端降水特征及其形成机理研究进行了回顾和总结。“菲特”的强降水过程主要分为两个阶段,造成了杭州湾一带和浙闽交界处两个强降水中心。“菲特”极端降水之所以产生,源于环境因子、地形和内部条件多尺度相互作用:环境因子涉及双台风作用、弱冷空气侵入、台风倒槽、垂直风切变和高空急流等,其中“丹娜丝”台风外围偏东气流源源不断的水汽输送是“菲特”极端降水形成的关键物理因子;山脉等地形增幅作用是浙江余姚等地出现历史性强降水的重要原因;水汽辐合和凝结与霰的融化和对流区雨滴的迁移是暴雨增幅重要的内部因素。 相似文献
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渤海海效应暴雪微物理过程的数值模拟 总被引：1，自引：0，他引：1
采用RAMS4.4中尺度数值模拟结果,分析了2008年12月4～6日1次渤海海效应暴雪的微物理过程。结果表明:(1)在降雪初期,云中水物质包含云水、雨水、霰、冰晶和雪晶,及地水物质为雨水和霰。随着温度的降低,中后期仅存冰晶和雪晶,产生降雪。由于整个过程以降雪为主,降雨时间短暂,通常忽略降雨,称为降雪过程。(2)本次海效应暴雪的微物理过程表现在两方面:一是"播撒-反馈"机制,二是合适的冰相过程。这两种过程均有利于降雪增幅。(3)西风槽前产生的环境云和冷空气流经渤海暖海面时形成的海效应云之间在合并时发生"播撒-反馈"作用,前者是中云,后者是低云,前者从上层播撒冰晶和雪晶到下层,使得降雪增强。(4)微物理过程另一个有利因素是环境温度,本次强冷空气使得降水云中的温度在-10～-15℃之间,有利于树枝状冰晶的增长,从而产生强降雪。强降雪发生在强上升运动、高相对湿度和适宜的温度的叠置区域。 相似文献
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A moisture budget over the Mackenzie River Basin (MRB) was computed using a high‐resolution mesoscale model with explicit microphysics for 3 lee cyclogenesis events. A unique feature of the calculation is that all the budget terms are calculated from the model and no residual terms are required. It was found that during the initial formative period of the lee cyclones, a large influx of moisture occurs at the western boundary. However, as the cyclone moves further east, a significant amount of moisture is withdrawn through the eastern and southern boundaries of the basin. Surface evaporation was found to be relatively large during the local day time and plays a vital ròle in initiating convection in the presence of frontal lifting south of 60°N within the basin. In 2 of the 3 cases, the total water in the basin increases over the history of the simulation as a result of substantial lateral flux convergence of total water content even though the total precipitation in these two events was nearly 1.4× the surface evaporation. For the 3rd cyclone, the total water in the basin decreases substantially because of precipitation and large outward moisture flux at the boundary. The dominant microphysical processes governing the transformation of various water species were condensation, deposition, autoconversion and accretion of cloud water by rain, accretion of cloud water by ice, melting of ice to rain water and evaporation of cloud and rain water. In the net horizontal flux convergence of water species, the largest was water vapor, followed by ice and cloud water. The net flux convergence of rainwater into the basin was small and the effect of the graupel processes is negligible. 相似文献
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The three-dimensional structures of summer precipitation over the South China Sea （SCS） and the East China Sea （ECS） are investigated based on tropical rainfall measurement mission （TRMM）. The primary results are as follows. First, both the convective and stratiform precipitation rates in the SCS are much higher than those of the ECS. The contribution of the convective cloud precipitation to the surface precipitation is primarily over the SCS and the ECS with a proportion of about 70%, but the contribution of convective cloud precipitation is slightly larger in the SCS than the ECS. The contribution of stratus precipitation is slightly larger in the ECS than that in the SCS. Second, the content of cloud particles and precipitation particles in the ECS in June was greater than that in the SCS, while in July and August, the content of cloud and precipitation particles in the ECS was less than that in the SCS. Third, the latent heat profile of the ECS is quite different from that of the SCS. In June, the peak values of evaporation and condensation latent heating rates in the ECS are greater than those in the SCS. In July and August, however, the peak values of evaporation and condensation latent heating rates in the ECS are about 0.05°/h less than those in the SCS. 相似文献
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Sea-ice retreat processes are examined in the Sea of Okhotsk. A heat budget analysis in the sea-ice zone shows that net heat
flux from the atmosphere at the water surface is about 77 W m−2 on average in the active ice melt season (April) due to large solar heating, while that at the ice surface is about 12 W m−2 because of the difference in surface albedo. The temporal variation of the heat input into the upper ocean through the open
water fraction corresponds well to that of the latent heat required for ice retreat. These results suggest that heat input
into the ice–upper ocean system from the atmosphere mainly occurs at the open water fraction, and this heat input into the
upper ocean is an important heat source for ice melting. The decrease in ice area in the active melt season (April) and the
geostrophic wind just before the melt season (March) show a correlation: the decrease is large when the offshoreward wind
is strong. This relationship can be explained by the following process. Once ice concentration is decreased (increased) by
the offshoreward (onshoreward) wind just before the melt season, solar heating of the upper ocean through the increased (decreased)
open water fraction is enhanced (reduced), leading to (suppressing) a further decrease in ice concentration. This positive
feedback is regarded as the ice–ocean albedo feedback, and explains in part the large interannual variability of the ice cover
in the ice melt season. 相似文献
16.
基于TRMM观测的亚洲——太平洋三个季风区的降水结构特征 总被引：1，自引：0，他引：1
The three-dimensional structure of precipitation on a seasonal scale in the Asian-Pacific＇s three monsoon regions is investigated based on the tropical rainfall measurement mission （TRMM） data. The results show that： （1） The maximum seasonal variation of the relative proportional difference of convective precipitation and stratiform rain occurs in the East Asian monsoon region, the second occurs in the Indian monsoon region, and the minimum is in the northwest Pacific monsoon region. In both the northwest Pacific mon soon region and the Indian monsoon region, the convective rain is proportionately larger than stratiform rain in all four seasons. （2） Cloud ice reaches its maximum at around 9 km. Cloud water＇s maximum range is between 3 and 4 km. The large value area of precipitation ice is mainly between 4 and 9 km. The precipi tation water particle is concentrated mostly below 4 km. The largest content is from the ground to 2 km. （3） The most remarkable variance of the content of cloud ice in the Indian monsoon region occurs from spring to winter, and the content of cloud water in the northwest Pacific is always higher than that in the other two regions. （4） The latent heat profile has a similar double-peak structure. The first peak is at 4 km and the second peak is at 2 km. In autumn and winter, the latent heat is higher in the northwest Pacific than in other two regions. In all three regions, the release of the latent heat is higher in summer and autumn than in spring and winter. 相似文献
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Piskunov V. N. Gainullin K. G. Petrov A. M. Zatevakhin M. A. Stankova E. N. 《Izvestiya Atmospheric and Oceanic Physics》2022,58(4):376-383
Izvestiya, Atmospheric and Oceanic Physics - A system of kinetic equations describing microphysical processes in a three-phase vapor–water–ice system is analyzed in terms of its... 相似文献
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雪热传导系数是海冰质量平衡过程中的重要物理参数，决定了穿透海冰的热传导通量。北冰洋海冰质量平衡浮标观测获得多年冰上冬季温度链剖面可以明显地区分冰雪界面。本文考虑到冰雪界面处温度随时间变化，再根据冰雪界面热传导通量连续假定，提出了新的雪热传导系数计算方法。受不同环境因素影响，多年冰上各个浮标的雪热传导系数在0.23~0.41 W/（m·K）之间，均值为（0.32±0.08） W/（m·K）。北冰洋多年冰上冬季穿过海冰的热传导通量最大发生在11月至翌年3月，约14~16 W/m2。结冰季节，来自海冰自身降温的热量对穿过海冰向大气传输的热量贡献逐月减少，从9月100%减小到12月的35%，翌年的1月至3月稳定在10%左右。夏季，短波辐射通能量通过热传导自上而下加热海冰，海冰上层温度高于下层，热量传播方向与冬季反向，往海冰内部传递。直到9月短波辐射完全消失，气温下降，热量再次转变为自下往上传递。从冰底热传导来看，夏季出现海冰向冰水界面传递热量现象。由于雪较好的绝热性，冰上覆雪极大地削弱了海冰上层热传导通量，从而减缓了秋冬季节的结冰速度。尽管受雪厚影响，多年冰上层热传导通量与气温依旧具有很好的线性关系，气温每降低1℃，热传导通量增加约0.59 W/m2。 相似文献