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1.
LI Weibiao 《大气科学进展》2004,21(2):269-276
It has long been recognized that the evolution ot marine storms may De strongly alIected Dy the nuxtransfer processes over the ocean. High winds in a storm can generate large amounts of spray, which canmodify the transfer of momentum, heat, and moisture across the air-sea interface. However, the role of seaspray and air-sea processes in western Pacific typhoons has remained elusive. In this study, the impact ofsea spray on air-sea fluxes and the evolution of a typhoon over the western Pacific is investigated using acoupled atmosphere-sea-spray modeling system. Through the case study of the recent Typhoon Fengshenfrom 2002, we found that: (1) Sea spray can cause a significant latent heat flux increase of up to 40% ofthe interfacial fluxes in the typhoon; (2) Taking into account the effects of sea spray, the intensity of themodeled typhoon can be increased by 30% in the 10-m wind speed, which may greatly improve estimatesof storm maximum intensity and, to some extent, improve the simulations of overall storm structure in theatmospheric model; (3) The effects of sea spray are mainly focused over the high wind regions around thestorm center and are mainly felt in the lower part of the troposphere. 相似文献
2.
海洋飞沫对台风“Morakot”结构影响的数值模拟研究 总被引：1，自引：0，他引：1
将海洋飞沫参数化引入到高分辨率、非静力中尺度模式中,并对0908号台风"Morakot"进行了数值模拟,研究了海洋飞沫对台风"Morakot"结构和强度的影响。结果表明:(1)不论是否考虑海洋飞沫作用,模式均能较好地模拟出台风"Morakot"的移动路径,说明海洋飞沫对其移动路径影响不大;(2)引入海洋飞沫参数化后,台风眼墙区域的切向风速、径向风速、垂直速度、涡度、云水混合比、雨水混合比等物理量均增强,表明飞沫对台风结构变化的影响明显;(3)海洋飞沫对台风"Morakot"演变的直接影响是在对流层低层,低层风速明显增大,大风速区的影响尤为显著;(4)飞沫的蒸发使台风范围内的潜热和感热通量明显增强,尤其是潜热通量,其大值区对应着台风中心附近的最大风速区。由于水汽和热量输送的增强,使台风眼壁附近的云水量与雨水量增多,因此降水强度明显增加。 相似文献
3.
中尺度海-气耦合模式GRAPES_OMLM对台风珍珠的模拟研究 总被引：1，自引：0，他引：1
利用全球/区域同化与预报系统GRAPES(Global/Regional Assimilation and Prediction System)和改进的Mellor-Yamada型海洋混合层模式OMLM(Ocean Mixed Layer Model),建立了一个新的中尺度海-气耦合模式GRAPES_OMLM,并利用该模式对发生于南海的台风珍珠(0601)进行了模拟研究,检验了GRAPES_OMLM对台风的模拟性能,并分析了局地海-气相互作用对台风的影响。结果表明,GRAPES_OMLM基本能模拟出台风天气过程中的主要物理过程。考虑了海-气相互作用的耦合试验所模拟出的台风强度、近台风中心最大风速以及台风后期移动路径,相对于两组控制试验(单独大气模式)的模拟结果都有较大的改进。而且,采用逐日变化海表温度作为下边界条件的控制试验2的模拟结果相对于SST不变的控制试验1更接近观测。耦合模式GRAPES_OMLM能较好地模拟出台风过境海表温度的变化,台风珍珠在其路径右侧有超过4.0℃的降温。SST的变化和海表风应力的变化呈反相关系,风应力的增大伴随着海洋近表层湍流动能(TKE)的加强,大风动力作用是SST降低的主要原因。SST的降低致使海洋向台风输送的热通量减少,进而削弱了台风的强度并改变台风环流结构,同时通过改变位势涡度趋势的一波结构(WN-1)来影响台风的移动路径。 相似文献
4.
Numerical Study on the Impacts of the Bogus Data Assimilation and Sea Spray Parameterization on Typhoon Ducts 总被引：1，自引：0，他引：1 
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下载免费PDF全文 FEI Jianfang DING Juli HUANG Xiaogang CHENG Xiaoping HU Xiaohua 《Acta Meteorologica Sinica》2013,27(3):308-321
The Weather Research and Forecasting model version 3.2 (WRF v3.2) was used with the bogus data assimilation (BDA) scheme and sea spray parameterization (SSP), and experiments were conducted to assess the impacts of the BDA and SSP on prediction of the typhoon ducting process induced by Typhoon Mindule (2004). The global positioning system (GPS) dropsonde observations were used for comparison. The results show that typhoon ducts are likely to form in every direction around the typhoon center, with the main type of ducts being elevated duct. With the BDA scheme included in the model initialization, the model has a better performance in predicting the existence, distribution, and strength of typhoon ducts. This improvement is attributed to the positive effect of the BDA scheme on the typhoon’s ambient boundary layer structure. Sea spray affects typhoon ducts mainly by changing the latent heat (LH) flux at the air-sea interface beyond 270 km from the typhoon center. The strength of the typhoon duct is enhanced when the boundary layer under this duct is cooled and moistened by the sea spray; otherwise, the typhoon duct is weakened. The sea spray induced changes in the air-sea sensible heat (SH) flux and LH flux are concentrated in the maximum wind speed area near the typhoon center, and the changes are significantly weakened with the increase of the radial range. 相似文献
5.
热带气旋过程中海-气界面热量交换 总被引：4，自引：1，他引：3
为探索热带气旋与海洋相互作用,采用国家海洋局南海分局Marex(马瑞克斯)数据浮标实测资料,计算了1986年南海的7个热带气旋海气界面热量交换值.结果表明:热带气旋海气界面热量交换强烈,主要贡献来自潜热通量;热带气旋环流内水温、气温均是下降趋势,气温下降更为明显;夏季热带气旋环流内,感热通量会出现负值,海面有效反射辐射通量出现减弱现象;秋季热带气旋环流内,感热通量和海面有效反射辐射通量显著加强;在热带气旋环流内,海面吸收的短波辐射通量均出现减弱现象;热带气旋环流内受到冷空气影响时,感热变得相当重要,热带气旋表现为对海洋的响应为主. 相似文献
6.
An investigation of the effects of wave state and sea spray on an idealized typhoon using an air-sea coupled modeling system 总被引：1，自引：0，他引：1
In this study, the impact of atmosphere-wave coupling on typhoon intensity was investigated using numerical simulations of an idealized typhoon in a coupled atmosphere-wave-ocean modeling system. The coupling between atmosphere and sea surface waves considered the effects of wave state and sea sprays on air-sea momentum flux, the atmospheric low-level dissipative heating, and the wave-state-affected sea- spray heat flux. Several experiments were conducted to examine the impacts of wave state, sea sprays, and dissipative heating on an idealized typhoon system. Results show that considering the wave state and sea-spray-affected sea-surface roughness reduces typhoon intensity, while including dissipative heating intensifies the typhoon system. Taking into account sea spray heat flux also strengthens the typhoon system with increasing maximum wind speed and significant wave height. The overall impact of atmosphere-wave coupling makes a positive contribution to the intensification of the idealized typhoon system. The minimum central pressure simulated by the coupled atmosphere-wave experiment was 16.4 hPa deeper than that of the control run, and the maximum wind speed and significant wave height increased by 31% and 4%, respectively. Meanwhile, within the area beneath the typhoon center, the average total upward air-sea heat flux increased by 22%, and the averaged latent heat flux increased more significantly by 31% compared to the uncoupled run. 相似文献
7.
We have analysed numerical simulations performed with a global 3D coupled atmosphere-ocean model to focus on the role of
atmospheric processes leading to sea surface temperature (SST) drift in the tropics. Negative SST errors occur coherently
in space and time with large positive errors in latent heat and momentum fluxes at the tropical air-sea interface, as diagnosed
from forced SST simulations. The warm pool in the western Pacific disappears after a few years of simulation. Strong SST gradients
enforce regions of high precipitation that are thin and stationary north of the equator. We detail the implications for the
ocean-atmosphere system of such upheaval in the deep convection location. A sensitivity experiment to empirically formulate
air-sea drag coefficient shows that the rapid warm pool erosion is not sensitive to changes in the formulation of the surface
drag coefficient over the oceans because the corresponding changes in turbulent heat fluxes and LW cooling approximately cancel
one another. In the eastern Pacific, the improvement in SST is striking and caused by feedbacks between SST, surface turbulent
fluxes and boundary layer cloud fraction, which decreases as SST warms.
Received: 8 December 1998 / Accepted: 6 January 2000 相似文献
8.
The Effect of Intensity： Typhoon-Induced SST Cooling on Typhoon The Case of Typhoon Chanchu （2006） 总被引：4，自引：0，他引：4
In order to investigate air-sea interactions during the life cycle of typhoons and the quantificational effects of typhoon-induced SST cooling on typhoon intensity, a mesoscale coupled air-sea model is developed based on the non-hydrostatic mesoscale model MM5 and the regional ocean model POM, which is used to simulate the life cycle of Typhoon Chanchu （2006） from a tropical depression to a typhoon followed by a steady weakening. The results show that improved intensity prediction is achieved after considering typhoon-induced SST cooling; the trend of the typhoon intensity change simulated by the coupled model is consistent with observations. The weakening stage of Typhoon Chanchu from 1200 UTC 15 May to 1800 UTC 16 May can be well reproduced, and it is the typhoon-induced SST cooling that makes Chanchu weaken during this period. Analysis reveals that the typhoon-induced SST cooling reduces the sensible and latent heat fluxes from the ocean to the typhoon＇s vortex, especially in the inner-core region. In this study, the average total heat flux in the inner-core region of the typhoon decrease by 57.2%, whereas typhoon intensity weakens by 46%. It is shown that incorporation of the typhoon-induced cooling, with an average value of 2.17℃, causes a 46-hPa weakening of the typhoon, which is about 20 hPa per 1℃ change in SST. 相似文献
9.
10.
本文利用包括海气耦合、气浪耦合及浪流耦合的完全耦合系统,着重研究了2006年“格美”(Kaemi)台风眼墙内的中尺度涡结构。中尺度涡作为影响台风眼墙非对称结构的内部因子,与风垂直切变密切相关,其发展过程受台风下垫面海洋状况的影响。在顺切变右侧,垂直气流逐渐增强,在顺切变左侧达到最大后逐渐减弱。当不考虑海表温度的冷涌反馈作用时,海气间的热通量输送较大,由此引起眼墙内的中尺度对流加强,但集中爆发区仍然位于顺切变方向,不受热通量输送变化的影响。当不考虑海浪对海表粗糙度的影响时,在较小的海表粗糙度条件下,眼墙非对称性减弱,使得中尺度对流涡在切向方向上的分布较为均匀。 相似文献
11.
采用2009—2013年CFSR(Climate Forecast System Reanalysis)大气和海洋再分析资料对黄海海气间热量通量和动量通量的特征进行统计分析,并通过FVCOMSWAVE浪流耦合模式对典型寒潮过程中风浪的影响效果进行模拟研究与对比分析。统计结果显示,通量受海表大风、海气温差及海洋环流等因子影响,秋冬季节强烈,春夏季节相对较弱,在寒潮活跃的冷季该海域的海流处于弱流期,风浪对海面通量的作用明显增强。海温特征也显示冷季的不稳定性显著强于暖季,因此该海域冷季具有更强的海气热量通量。沿岸站点的比较显示,南部吕泗站面向更开阔的东海海域,其平均波高高出北部20%左右。这与沿海南部通量强于北部特征对应。数值模拟显示,在寒潮过程中,海气界面热量通量和动量通量输送比多年月平均状态显著增强,动量通量增大1~5倍,热量通量增大1~6倍。寒潮过程入海冷锋走向、强度、移动方向显著影响海面热量通量和动量通量大值区的分布。偏北路寒潮纬向型冷锋入海,其强度东部大于西部,造成通量大值区形成在黄海东北部,而偏西路寒潮经向型冷锋入海,其强度南部大于北部,造成通量大值区形成在黄海南部。同时偏北路径寒潮强度大于偏西路径,海气动量通量响应较偏西路径强约25%,热量通量强约50%。耦合风浪作用的模拟显示,海气间热量通量和动量通量明显增大,对不同强度风浪,浪高增加1.5倍,动量通量最大值增大约2倍,热量通量增大10~160 W/m2;浪高减弱至0.5倍,动量通量最大值则减弱约40%,热量通量减小10~55 W/m2。冷锋及其驱动的风浪强烈影响区域海气通量时空特征。 相似文献
12.
Turbulent surface heat fluxes (latent and sensible heat) are the two most important parameters through which air–sea interaction takes place at the ocean–atmosphere interface. These fluxes over the global ocean are required to drive ocean models and to validate coupled ocean–atmosphere global models. But because of inadequate in situ observations these are the least understood parameters over the tropical Indian Ocean. Surface heat fluxes also contribute to the oceanic heat budget and control the sea surface temperature in conjunction with upper ocean stratification and ocean currents. The most widely used flux products in diagnostic studies and forcing of ocean general circulation models are the ones provided by the National Centres for Environment Prediction (NCEP) reanalysis. In this study we have compared NCEP reanalysed marine meteorological parameters, which are used for turbulent heat fluxes, with the moored buoy observation in the south-eastern Arabian Sea. The NCEP latent heat flux (LHF) and sensible heat flux (SHF) derived from bulk aerodynamic formula are also compared with that of ship and buoy derived LHF and SHF. The analysis is being carried out during the pre-monsoon and monsoon season of 2005. The analysis shows that NCEP latent as well as sensible heat fluxes are largely underestimated during the monsoon season, however, it is reasonably comparable during the pre-monsoon period. This is largely due to the underestimation of NCEP reanalysis air temperature (AT), wind speed (WS) and relative humidity (RH) compared to buoy observations. The mean differences between buoy and NCEP parameters during the monsoon (pre-monsoon) period are ~21% (~14%) for WS, ~6% (~3%) for RH, and ~0.75% (0.9%) for AT, respectively. The sudden drop in AT during rain events could not be captured by the NCEP data and, hence, large underestimations in SHF. During the pre-monsoon period, major contribution to LHF variations comes from WS, however, both surface winds and relative humidity controls the LHF variations during the monsoon. LHF is mainly determined by WS and RH during the monsoon and, WS is the main contributor during the pre-monsoon. 相似文献
13.
Three experiments for the simulation of typhoon Sinlaku (2002) over the western North Pacific are performed in this study by using the Canadian Mesoscale Compressible Community (MC2) atmospheric model. The objective of these simulations is to investigate the air-sea interaction during extreme weather conditions, and to determine the sensitivity of the typhoon evolution to the sea surface temperature (SST)cooling induced by the typhoon. It is shown from the three experiments that the surface heat fluxes have a substantial influence on the slow-moving cyclone over its lifetime. When the SST in the East China coastal ocean becomes 1℃ cooler in the simulation, less latent heat and sensible heat fluxes from the underlying ocean to the cyclone tend to reduce the typhoon intensity. The cyclone is weakened by 7 hPa at the time of its peak intensity. The SST cooling also has impacts on the vertical structure of the typhoon by weakening the warm core and drying the eye wall. With a finer horizontal resolution of (1/6)°×(1/6)°, the model produces higher surface wind, and therefore more surface heat fluxes are emitted from the ocean surface to the cyclone, in the finer-resolution MC2 grid compared with the relatively lower resolution of 0.25°×0.25°MC2 grid. 相似文献
14.
In this study a coupled air–sea–wave model system, containing the model components of GRAPES-TCM, ECOM-si and WAVEWATCH III, is established based on an air–sea coupled model. The changes of wave state and the effects of sea spray are both considered. Using the complex air–sea–wave model, a set of idealized simulations was applied to investigate the effects of air–sea–wave interaction in the upper ocean. Results show that air–wave coupling can strengthen tropical cyclones while air–sea coupling can weaken them; and air–sea–wave coupling is comparable to that of air–sea coupling, as the intensity is almost unchanged with the wave model coupled to the air–sea coupled model. The mixing by vertical advection is strengthened if the wave effect is considered, and causes much more obvious sea surface temperature (SST) decreases in the upper ocean in the air–sea coupled model. Air–wave coupling strengthens the air–sea heat exchange, while the thermodynamic coupling between the atmosphere and ocean weakens the air–sea heat exchange: the air–sea–wave coupling is the result of their balance. The wave field distribution characteristic is determined by the wind field. Experiments are also conducted to simulate ocean responses to different mixed layer depths. With increasing depth of the initial mixed layer, the decrease of SST weakens, but the temperature decrease of deeper layers is enhanced and the loss of heat in the upper ocean is increased. The significant wave height is larger when the initial mixed layer depth increases. 相似文献
15.
Hurricane intensity and track are strongly affected by air-sea interactions. Classified as following swells, crossing swells, and opposing swells, the observed wave height was parameterized by using the 10-m wind speed collected on 5 buoys by the National Buoy Data Center during 13 hurricane events. The path information of these 13 hurricanes was obtained from the National Hurricane Center Best Track (NHC-BT). Results show that the wave height increases exponentially with the 10-m wind speed, and the wave height reaches the maximum value, 11.2 m (8.1 m), when 10-m wind speed is 40 m s-1 under the following and crossing (opposing) swell conditions. We find that the wave steepness (the ratio of wave height to wave length) is proportional to the -2/3 power of the wave age (the ratio of wave phase velocity to 10-m wind speed). The parameterizations of friction velocity and drag coefficient are tested using the buoy data collected in moderate to high wind under following, crossing and opposing swell conditions. A wave age dependent equation for drag coefficient is found more accurate and suggested for future usage in numerical models. Further, these algorithms also suggest that wind-swell orientation needs to be considered to retrieve accurate surface drag under high winds and strong swells. 相似文献
16.
利用中尺度数值模式WRF v3.8中的YSU、MYJ、QNSE、ACM2、UW、GBM、Boulac七种不同边界层参数化方案,采用高分辨率（1.33 km）数值试验的方法研究了不同边界层方案对模拟台风“莫兰蒂”（1614）登陆减弱阶段的移动路径、强度、结构、降水量、近地层有关物理量场分布等方面的影响,结果表明:（1）“莫兰蒂”台风登陆减弱阶段,不同边界层方案对台风路径、强度、降水量模拟影响显著,24 h内模拟台风路径、最低气压、最大风速及24 h累积降水量极值的最大差异分别达80 km、11 hPa、27 m s?1及241 mm;（2）Boulac方案模拟台风路径与实况最为接近,GBM、YSU和MYJ方案分别次之,ACM2和UW方案再次之,而QNSE方案最差;UW和QNSE方案模拟的最低气压以及MYJ和QNSE方案模拟的最大风速与观测最为接近;不同边界层方案均模拟出台风登陆阶段最低气压逐渐升高以及其升高速率在台风登陆后大于登陆前的特征,这与实况一致,但台风登陆前各方案模拟最低气压升高速度均大于实况,而台风登陆后却又不及实况;（3）Boulac方案模拟的24 h降水分布、强降水落区、结构、强度和各量级降水TS评分均最优,MYJ方案次之;而QNSE、UW和ACM2方案雨带向西北方向推进过快,各量级降水TS评分均较差;（4）综合台风路径、强度和降水模拟,Boulac和MYJ方案相对最优,其中Boulac方案在台风路径和降水模拟上更优,而MYJ方案在台风强度模拟上更优;YSU和GBM方案次之,而QNSE、UW和ACM2方案相对较差;（5）不同边界层方案计算的近地层潜热通量、感热通量显著不同,进而影响台风路径、强度、降水量模拟存在显著差异。比较而言,QNSE方案潜热通量相对异常偏高,MYJ和Boulac方案量值适中,其余方案相对偏低;QNSE方案感热通量相对略偏高,MYJ方案适中,其他方案则相对显著偏低;（6）不同边界层方案模拟降水区边界层热、动力结构显著不同,其中Boulac方案具有较明显优势,尤其是对日间边界层结构的模拟。 相似文献
17.
在不同的环境风场作用下台风移动路径出现差异,导致海洋冷尾流呈现不同的响应特征,从而对台风强度产生影响。利用海气耦合模式进行理想试验,模拟研究了在均匀的东、西风场条件下冷尾流的响应特征,以分析台风强度出现差异的原因。研究结果表明,在均匀的东风环境场与β效应的共同作用下,台风路径呈西北方向移动,冷尾流沿台风路径呈非对称分布,右侧降温幅度大于左侧,并持续影响台风内核海气界面热通量的输送。而均匀的西风环境场抵御了部分β效应,使得台风东移北抬,当强度增强到一定程度后向西北方向移动,最大幅度的冷尾流出现在台风南侧,眼区热通量的输送受冷尾流影响较小。另外,在台风快速加强阶段,眼区范围内的潜热通量输送对台风加强更为关键。 相似文献
18.
Buoy and satellite observations of mesoscale cellular convection (MCC) over the East China Sea in the vicinity of the Kuroshio current have been made during 14–18 February 1975, as a part of the Air Mass Transformation Experiment (AMTEX). Surface observations of solar radiation from spar buoys indicate the distinct passage of open and closed MCC that formed and continued for three consecutive days during an outbreak of cold polar air over the much warmer Kuroshio. A critical air-sea temperature of –5 °C for the occurrence of MCC has been substantiated. The time required for the passage of solar radiation peaks coupled with the buoy wind speed gave a computed closed cell diameter of 28 km, comparable to estimates from satellite photographs.The horizontal component of wind beneath the cloudy portion of a closed cell, due to convection, has been estimated as 0.6 m s–1. This represents the speed at which air near the sea surface moves from the edge toward the center of a closed cell. Also, the temperature difference obtained near the sea surface between the relatively cold descending branch and the warm ascending branch is 0.2°C. Similarly, the specific humidity difference of the less moist descending air near the edge and the moist ascending air near cell center is 9% (0.4 g/kg). Some indications were also found in the variation of horizontal wind direction with the passage of closed cells, since wind variations at the edge of passing cells exceeded the mean sequential variability (10.6 ° compared to 9.4 °).Sensible heat flux calculations associated with closed MCC suggest that strong surface heating can be associated with closed cells, previously reported by Hubert (1966) to be a characteristic of only open cells.Finally, the results of this study should remove any disclaimers that MCC appear in satellite photography simply because of a resolution bias and that the consideration of all visible clouds actually present would remove any periodicity one might expect to see in surface observations. 相似文献
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WANG Zi-Qianand DUAN An-Min 《大气和海洋科学快报》2012,(3):170-175
A new mesoscale air-sea coupled model (WRF- OMLM-Noh) was constructed based on the Weather Research and Forecasting (WRF) model and an improved Mellor-Yamada ocean mixed-layer model from Noh and Kim (OMLM-Noh). Through off-line tests and a simulation of a real typhoon, the authors compared the performance of the WRF-OMLM-Noh with another existing ocean mixed-layer coupled model (WRF-OMLM-Pollard). In the off-line tests with Tropical Ocean Global Atmosphere Program’s Coupled Ocean Atmosphere Response Experiment (TOGA-COARE) observational data, the results show that OMLM-Noh is better able to simulate sea surface temperature (SST) variational trends than OMLM -Pollard. Moreover, OMLM-Noh can sufficiently reproduce the diurnal cycle of SST. Regarding the typhoon case study, SST cooling due to wind-driven ocean mixing is underestimated in WRF-OMLM-Pollard, which artificially increases the intensity of the typhoon due to more simulated air-sea heat fluxes. Compared to the WRF- OMLM-Pollard, the performance of WRF-OMLM-Noh is superior in terms of both the spatial distribution and temporal variation of SST and air-sea heat fluxes. 相似文献