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Journal of Tropical Meteorology 2009年第2期15卷 148-154页

作者：李小凡 noaa/nesdis/center for satellite applications and research camp springs

A lag correlation analysis is conducted with a 21-day TOGA COARE cloud-resolving model simulation data to identify the phase relation between surface rainfall and convective available potential energy (CAPE) and associated physical processes. The analysis shows that the maximum negative lag correlations between the model domain mean CAPE and rainfall occurs around lag hour 6. The minimum mean CAPE lags mean and convective rainfall through the vapor condensation and depositions,water vapor convergence,and heat divergence whereas it lags stratiform rainfall via the transport of hydrometeor concentration from convective regions to raining stratiform regions,vapor condensation and depositions,water vapor storage,and heat divergence over raining stratiform regions.

关键词： phase relation convective available potential energy surface rainfall cloud-resolving model simulation

applications of AMSR-E Measurements for Tropical Cyclone Predictions PartⅠ: Retrieval of Sea Surface Temperature and Wind Speed

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Advances in Atmospheric Sciences 2008年第2期25卷 227-245页

作者： Banghua YAN Fuzhong WENG noaa Joint center for satellite Data Assimilation Camp Springs MD USA noaa/nesdis/center for satellite applications and research Camp Springs MD USA

Existing satellite microwave algorithms for retrieving Sea Surface Temperature （SST） and Wind （SSW） are applicable primarily for non-raining cloudy conditions. With the launch of the Earth Observing System （EOS） Aqua satellite in 2002, the Advanced Microwave Scanning Radiometer （AMSRoE） onboard provides some unique measurements at lower frequencies which are sensitive to ocean surface parameters under adverse weather conditions. In this study, a new algorithm is developed to derive SST and SSW for hurricane predictions such as hurricane vortex analysis from the AMSRoE measurements at 6.925 and 10.65 GHz. In the algorithm, the effects of precipitation emission and scattering on the measurements are properly taken into account. The algorithm performances are evaluated with buoy measurements and aircraft dropsonde data. It is found that the root mean square （RMS） errors for SST and SSW are about 1.8 K and 1.9 m s^- 1, respectively, when the results are compared with the buoy data over open oceans under precipitating clouds （e.g., its liquid water path is larger than 0.5 mm）, while they are 1.1 K for SST and 2.0 m s^-1 for SSW, respectively, when the retrievals are validated against the dropsonde measurements over warm oceans. These results indicate that our newly developed algorithm can provide some critical surface information for tropical cycle predictions. Currently, this newly developed algorithm has been implemented into the hybrid variational scheme for the hurricane vortex analysis to provide predictions of SST and SSW fields.

关键词： Ocean surface temperature ocean surface wind AMSR-E hurricane vortex analysis

A Review of Cloud-Resolving Model Studies of Convective Processes

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Advances in Atmospheric Sciences 2008年第2期25卷 202-212页

作者： Xiaoqing WU Xiaofan LI Department of Geological and Atmospheric Sciences Iowa State University Ames Iowa USA Joint center for satellite Data Assimilation and noaa/nesdis/center for satellite applications and research Camp Springs Maryland USA

Convective processes affect large-scale environments through cloud-radiation interaction, cloud micro- physical processes, and surface rainfall processes. Over the last three decades, cloud-resolving models （CRMs） have demonstrated to be capable of simulating convective-radiative responses to an imposed large-scale forcing. The CRM-produced cloud and radiative properties have been utilized to study the convective- related processes and their ensemble effects on large-scale circulations. This review the recent progress on the understanding of convective processes with the use of CRM simulations, including precipitation processes; cloud microphysical and radiative processes; dynamical processes; precipitation efficiency; diurnal variations of tropical oceanic convection; local-scale atmosphere-ocean coupling processes; and tropical convective-radiative equilibrium states. Two different ongoing applications of CRMs to general circulation models （GCMs） are discussed： replacing convection and cloud schemes for studying the interaction between cloud systems and large-scale circulation, and improving the schemes for climate simulations.

关键词： cloud-resolving models (CRMs) convective processes simulations of convection and clouds

Torrential Rainfall Responses to Ice Microphysical Processes during Pre-Summer Heavy Rainfall over Southern China

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Advances in Atmospheric Sciences 2012年第3期29卷 493-500页

作者：沈新勇刘佳 Xiaofan Li Key Laboratory of Meteorological Disaster of Ministry of Education Nanjing University of Information Science and TechnologyNanjing 210044 noaa/nesdis/center for satellite applications and research Camp SpringsMarylandUSA

In this study, the effects of key ice microphysical processes on the pre-summer heavy rainfall over southern China during 3-8 June 2008 were investigated. A series of two-dimensional sensitivity cloud-resolving model simulations were forced with zonally uniform vertical velocity, zonal wind, horizontal temperature, and water vapor advection data from the National centers for Environmental Prediction （NCEP）/Global Data Assimilation System （GDAS）. The effects of key ice microphysical processes on the responses of rainfall to large-scale forcing were analyzed by comparing two sensitivity experiments with a control experiment. In one sensitivity experiment, ice crystal radius, associated with depositional growth of snow from cloud ice, was reduced from 100 #m in the control experiment to 50 #m, and in the other sensitivity experiment the efficiency of the growth of graupel from the accretion of snow was reduced to 50~ from 100% in the control experiment. The results show that the domain-mean rainfall responses to these ice microphysical processes are stronger during the decay phase than during the onset and mature phases. During the decay phase, the increased mean rain rate resulting from the decrease in ice crystal radius is associated with the enhanced mean local atmospheric drying, the increased mean local hydrometeor loss, and the suppressed mean water vapor divergence. The increased mean rain rate caused by the reduction in accretion efficiency is related to the reduced mean water vapor divergence and the enhanced mean local hydrometeor loss.

关键词： ice crystal radius accretion efficiency cloud-resolving model simulation

An Analysis of Thermally-Related Surface Rainfall Budgets Associated with Convective and Stratiform Rainfall

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Advances in Atmospheric Sciences 2011年第5期28卷 1099-1108页

作者：周玉淑 Xiaofan LI Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 noaa//nesdis/center for satellite applications and research Camp Springs Maryland

Both water vapor and heat processes play key roles in producing surface *** the water vapor effects of sea surface temperature and cloud radiative and microphysical processes on surface rainfall have been investigated in previous studies,the thermal effects on rainfall are analyzed in this study using a series of two-dimensional equilibrium cloud-resolving model experiments forced by zonally-uniform,constant,large-scale zonal wind and zero large-scale vertical *** analysis of thermally-related surface rainfall budget reveals that the model domain mean surface rain rate is primarily associated with the mean infrared cooling *** rainfall and transport of hydrometeor concentration from convective regions to raining stratiform regions corresponds to the heat divergence over convective regions,whereas stratiform rainfall corresponds to the transport of hydrometeor concentration from convective regions and heat divergence over raining stratiform *** heat divergence over convective regions is mainly balanced by the heat convergence over rainfall-free regions,which is,in turn,offset by the radiative cooling over rainfall-free *** sensitivity experiments of rainfall to the effects of sea surface temperature and cloud radiative and microphysical processes show that the sea surface temperature and cloud processes affect convective rainfall through the changes in infrared cooling rate over rainfall-free regions and transport rate of heat from convective regions to rainfall-free regions.

关键词： surface rainfall infrared cooling heat divergence cloud-resolving model simulation

Contribution of cloud condensate to surface rainfall process

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Progress in Natural Science:Materials International 2006年第9期16卷 967-973页

作者： ZHOU Yushu , GUI Xiaopeng and LI Xiaofan ( Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Joint center for satellite Data Assimilation and noaa/nesdis/Office of research and applications camp springs, Maryland, USA) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Joint center for satellite Data Assimilation NOAA NESDIS Office of Research and Applications Camp Springs MD United States

Contribution of cloud condensate to surface rainfall processes is investigated in a life span of tropical convection based on hourly data from a two-dimensional cloud resolving simulation. The model is forced by the large-scale vertical velocity, zonal wind and horizontal advections obtained from tropical ocean global atmosphere coupled ocean-atmosphere response experiment (TOGA COARE). The results show that during the genesis, development, and decay of tropical convection, calculations with water vapor overestimate surface rain rate, and cloud condensate plays an important role in correcting overestimation in surface rain rates. The analysis is carried out in deep convective clouds and anvil clouds during the development of tropical convection. The surface rain rates calculated with water vapor in deep convective clouds and anvil clouds have similar magnitudes, the large surface rain rate appears in deep convective clouds due to the consumption of water hydrometeors whereas the small surface rain rate occurs in anvil clouds because of the gain of ice hydrometeors. Further analysis of the grid data shows that the surface rain rates calculated with water vapor and with cloud condensate are negatively correlated with the correlation coefficient of - 0.85, and the surface rain rate calculated with cloud condensate is mainly contributed to the water hydrometeors in the tropical deep convective regime.

关键词： cloud condensate surface rain rate cloud resolving simulation.

Effects of sea surface temperature,cloud radiative and microphysical processes,and diurnal variations on rainfall in equilibrium cloud-resolving model simulations

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Chinese Physics B 2012年第5期21卷 308-315页

作者：蒋哲李小凡周玉淑高守亭 Institute of Remoting Sensing applications Chinese Academy of Sciences noaa/nesdis/center for satellite applications and research camp springs Maryland 21029USA Laboratory of Cloud-Precipitation Physics and Severe Storms(LACS) Institute of Atmospheric PhysicsChinese Academy of Sciences

The effects of sea surface temperature（SST）,cloud radiative and microphysical processes,and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolving model *** a rain rate of higher than 3 mm.h 1,water vapor convergence *** rainfall amount decreases with the decrease of SST from 29℃ to 27℃,the inclusion of diurnal variation of SST,or the exclusion of microphysical effects of ice clouds and radiative effects of water clouds,which are primarily associated with the decreases in water vapor ***,the amount of rainfall increases with the increase of SST from 29℃ to 31℃,the exclusion of diurnal variation of solar zenith angle,and the exclusion of the radiative effects of ice clouds,which are primarily related to increases in water vapor *** a rain rate of less than 3 mm.h 1,water vapor divergence *** rainfall statistics for rain rates of higher than 3 mm.h 1,the decrease of SST from 29℃ to 27℃ and the exclusion of radiative effects of water clouds in the presence of radiative effects of ice clouds increase the rainfall amount,which corresponds to the suppression in water vapor *** exclusion of microphysical effects of ice clouds decreases the amount of rainfall,which corresponds to the enhancement in water vapor *** amount of rainfall is less sensitive to the increase of SST from 29℃ to 31℃ and to the radiative effects of water clouds in the absence of the radiative effects of ice clouds.

关键词： rain rate sea surface temperature radiative and microphysical effects of ice and water clouds diurnal variation

A Modeling Study of Diurnal Rainfall Variations during the 21-Day Period of TOGA COARE

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Advances in Atmospheric Sciences 2009年第5期26卷 895-905页

作者：高守亭崔晓鹏 Xiaofan LI Laboratory of Cloud-Precipitation Physics and Severe Storms （ LACS） Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Joint center for satellite Data Assimilation and noaa/nesdis/center for satellite applications and research Camp Springs Maryland USA

The surface rainfall processes and diurnal variations associated with tropical oceanic convection are examined by analyzing a surface rainfall equation and thermal budget based on hourly zonal-mean data from a series of two-dimensional cloud-resolving simulations. The model is integrated for 21 days with imposed large-scale vertical velocity, zonal wind, and horizontal advection obtained from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment （TOGA COARE） in the control experiment. Diurnal analysis shows that the infrared radiative cooling after sunset, as well as the advective cooling associated with imposed large-scale ascending motion, destabilize the atmosphere and release convective available potential energy to energize nocturnal convective development. Substantial local atmospheric drying is associated with the nocturnal rainfall peak in early morning, which is a result of the large condensation and deposition rates in the vapor budget. Sensitivity experiments show that diurnal variations of radiation and large-scale forcing can produce a nocturnal rainfall peak through infrared and advective cooling, respectively.

关键词： diurnal rainfall variation cloud-resolving simulation tropical oceanic convection TOGACOARE

A modeling study of relation between cloud amount and SST over Western Tropical Pacific cloudy regions during TOGA COARE

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Progress in Natural Science:Materials International 2009年第2期19卷 187-193页

作者： Shouting Gaoa,Xiaopeng Cui a,Xiaofan Li b a Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China b Joint center for satellite Data Assimilation and noaa/nesdis/center for satellite applications and research,camp springs,MD,USA Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Joint center for satellite Data Assimilation and noaa/nesdis/center for satellite applications and research Camp Springs MD USA

The relationship between cloud amount and sea surface temperature (SST) over Western Tropical Pacific cloudy regions during TOGA COARE is investigated based on hourly grid simulation data from a two-dimensional coupled ocean-cloud resolving atmosphere model. The model is forced by the large-scale vertical velocity and zonal wind observed and derived from TOGA COARE for a 50-day period. The cloud amount becomes smaller when the ocean surface gets warmer,which is similar to previous relations obtained from observational analyses. As SST increases,the atmospheric temperature increases whereas the surface sensible heat flux decreases. The atmospheric water vapor is not sensitive to SST whereas the surface evaporation flux decreases as SST increases. These indicate that the oceanic effects do not play an important role in determining atmospheric heat and water vapor budgets. The cold atmosphere pro-duces a larger amount of ice clouds that cover a larger area than the warm atmosphere does. The large amounts of ice clouds lead to cooling of the ocean surface through reflecting large amount of solar radiation back to the space. Thus,the negative correlation between the cloud amount and SST only accounts for the important atmospheric effects on the ocean.

关键词： Cloud amount Sea surface temperature Coupled ocean-cloud resolving atmosphere model TOGA COARE

Thermal aspect of the diurnal variation of tropical convective and stratiform rainfall

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Chinese Physics B 2011年第10期20卷 511-520页

作者：崔晓鹏李小凡 Laboratory of Cloud-Precipitation Physics and Severe Storms (LACS) Institute of Atmospheric Physics Chinese Academy of Sciences noaa/nesdis/Office of research and applications Camp Springs Maryland USA

The diurnal variation of radiation plays a key role in determining the diurnal variations of tropical oceanic con- vective and stratiform rainfall, and the examination of such a relationship requires a direct link between the radiation term in a heat budget and the surface rain rate in a cloud budget. Thus, the thermally related surface rainfall budgets derived from the combination of cloud and heat budgets are analysed with two-dimensional equilibrium cloud-resolving model simulation data to study the effects of sea surface temperature （SST） and cloud radiative, and microphysical processes on the diurnal variations of convective and stratiform rainfall. The results show that the increase in SST, the inclusion of diurnal variation of SST and the exclusion of cloud radiative processes increase negative diurnal anomalies of heat divergence over rainfall-free regions during the nighttime through changing the vertical structures of diurnal anomaly of radiation in the troposphere. The strengthened negative diurnal anomalies of heat divergence over rainfall- free regions enhance positive diurnal anomalies of heat divergence over convective regions, which intensifies the positive diurnal anomaly of convective rainfall. The exclusion of microphysical effects of ice clouds increases the negative diurnal anomaly of heat divergence over rainfall-free regions during the nighttime through reducing latent heat; this appears to enhance the positive diurnal anomaly of heat divergence over raining stratiform regions, and thus stratiform rMnfall.

关键词： thermal aspects diurnal variation tropical convective and stratiform rainfall