Chou M.-D., 1992: A solar radiation model for use in climate studies. J. Atmos. Sci., 49, 762- 772.10.1175/1520-0469(1992)0492.0.CO;21eb2aaec-31c9-4a58-a53b-a71873551586d6d8d5d4bf9b84980f6b2893f70e9662http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F23864118_A_solar_radiation_model_for_use_in_climate_studiesrefpaperuri:(23c1cf7ab238f543a1091bd9e075ca50)http://www.researchgate.net/publication/23864118_A_solar_radiation_model_for_use_in_climate_studiesAbstract A solar radiation routine has been developed for use in climate studies. It includes the absorption and scattering due to ozone, water vapor, oxygen, carbon dioxide, clouds, and aerosols. Rayleigh scattering is also included. The UV and visible region ( 0.69 m), the broadband parameterization is used to compute the absorption by water vapor in a clear atmosphere, and the k -distribution method is applied to compute fluxes in a scattering atmosphere. The reflectivity and transmissivity of a scattering layer are computed analytically using the delta-four-stream discrete-ordinate approximation. The two-stream adding method is then applied to compute fluxes for a composite of clear and scattering layers. Compared to the results of high spectral resolution and detailed multiple-scattering calculations, fluxes and heating rate are accurately computed to within a few percent. The high accuracy of flux and heating rate calculations is achieved with a reasonable amount of computing time. With the UV and visible region grouped into four bands, this solar radiation routine is useful not only for climate studies but also for studies on the photolysis in the upper atmosphere and the photosynthesis in the biosphere. |
Chou M.-D., M. J. Suarez, 1994: An efficient thermal infrared radiation parameterization for use in general circulation model. NASA Tech. Memo. 104606,Vol. 3, 85 pp. [Available from NASA/Goddard Space Flight Center, Code 913, Greenbelt, MD 20771.]fa72c6c4-cc2b-49c8-af91-63c829215618/s?wd=paperuri%3A%2841ee95cca090103dca36e2773cac8cec%29&filter=sc_long_sign&sc_ks_para=q%3DAn%20Efficient%20Thermal%20Infrared%20Radiation%20Parameterization%20For%20Use%20In%20General%20Circulation%20Models&tn=SE_baiduxueshu_c1gjeupa&ie=utf-8 |
Chou M. D., D. P. Kratz, and W. Ridgway, 1991: Infrared radiation parameterizations in numerical climate models. J.Climate, 4, 424- 437.10.1175/1520-0442(1991)0042.0.CO;2c934f3c3-034a-462b-a7b1-8b0ce3b868b403545b339ec55c925a7bf8cf9be57de1http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F24152410_Infrared_radiation_parameterizations_in_numerical_climate_modelsrefpaperuri:(c76f7b6209a19f1660d3b13a70430cfa)http://www.researchgate.net/publication/24152410_Infrared_radiation_parameterizations_in_numerical_climate_modelsAbstract Parameterizations for infrared radiation (IR) in clear atmosphere can be made fast and accurate by grouping spectral regions with similar radiative properties, and by separating the low pressure region of the atmosphere from the high pressure region. Various approaches are presented in this study to parameterizing the broadband transmission functions for use in numerical climate models. For water vapor and carbon dioxide (CO 2 ) bands, the transmission functions are parameterized separately for the middle atmosphere (0.0130 mb) and for the region below. In the middle atmosphere where the dependence of absorption on pressure and temperature is not strong, the diffuse transmission functions are derived from that at a reference pressure and temperature. In the lower stratosphere and the troposphere, the spectra are grouped into band-center regions and band-wing regions. One-parameter scaling is applied to approximate a nonhomogeneous path with an equivalent homogeneous path, and the diffuse transmittances are either fit by analytical functions or interpolated from precomputed tables. As opposed to the one-parameter scaling, which applies only to a relatively narrow pressure range, the two-parameter scaling (commonly called the Curtis-Godson approximation) is applied to parameterizing the carbon dioxide (CO 2 ) and ozone (O 3 ) transmission functions in both the middle and the lower atmosphere. The diffuse transmission functions are simply interpolated from three small precomputed tables. The accuracies of cooling rates in the 15-m band computed using the approximation for both the middle and the lower atmospheres are comparable with that using the parameterizations separately for the middle and the lower atmospheres. The radiative effect of nitrous oxide (N 2 O) and methane (CH 4 ) is also examined. Parameterizations are presented for the N 2 O and CH 4 diffuse transmission functions. |
Chou M. D., M. J. Suarez, C. H. Ho, M. M. H. Yan, and K. T. Lee, 1998: Parameterizations for cloud overlapping and shortwave single-scattering properties for use in general circulation and cloud ensemble models. J.Climate, 11, 202- 214.10.1175/1520-0442(1998)0112.0.CO;236424a1b-a461-4faf-9fde-4b25e51fd45a682ffe932bd3ebc9a6d5943c31bf0527http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F249610109_Parameterizations_for_Cloud_Overlapping_and_Shortwave_Single-Scattering_Properties_for_Use_in_General_Circulation_and_Cloud_Ensemble_Modelsrefpaperuri:(79c379c5366f1521863c8d7b98340b37)http://www.researchgate.net/publication/249610109_Parameterizations_for_Cloud_Overlapping_and_Shortwave_Single-Scattering_Properties_for_Use_in_General_Circulation_and_Cloud_Ensemble_ModelsAbstract Parameterizations for cloud single-scattering properties and the scaling of optical thickness in a partial cloudiness condition have been developed for use in atmospheric models. Cloud optical properties are parameterized for four broad bands in the solar (or shortwave) spectrum; one in the ultraviolet and visible region and three in the infrared region. The extinction coefficient, single-scattering albedo, and asymmetry factor are parameterized separately for ice and water clouds. Based on high spectral-resolution calculations, the effective single-scattering coalbedo of a broad band is determined such that errors in the fluxes at the top of the atmosphere and at the surface are minimized. This parameterization introduces errors of a few percent in the absorption of shortwave radiation in the atmosphere and at the surface. Scaling of the optical thickness is based on the maximum-random cloud-overlapping approximation. The atmosphere is divided into three height groups separated approximately by the 400- and 700-mb levels. Clouds are assumed maximally overlapped within each height group and randomly overlapped among different groups. The scaling is applied only to the maximally overlapped cloud layers in individual height groups. The scaling as a function of the optical thickness, cloud amount, and the solar zenith angle is derived from detailed calculations and empirically adjusted to minimize errors in the fluxes at the top of the atmosphere and at the surface. Different scaling is used for direct and diffuse radiation. Except for a large solar zenith angle, the error in fluxes introduced by the scaling is only a few percent. In terms of absolute error, it is within a few watts per square meter. |
Cui X. P., X. F. Li, 2006: Role of surface evaporation in surface rainfall processes. J. Geophys. Res., 111,D17112, doi: 10.1029/2005JD006876.10.1029/2005JD006876110d1a9a-4d68-4190-84a8-89925008c8674100fb1f13ebcdf72be3cfd5d3f248fdhttp%3A%2F%2Fcpfd.cnki.com.cn%2FArticle%2FCPFDTOTAL-ZGQX201009001043.htmrefpaperuri:(830d5847df15153bf5c74c6c0af1b078)http://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGQX201009001043.htmThe roles of surface evaporation in tropical surface rainfall processes in rainfall regions (raining stratiform and convective regions) and rainfall-free regions (nonraining stratiform and clear-sky regions) are investigated on the basis of the data from a series of two-dimensional cloud-resolving simulations. The model is integrated for 21 days with imposed zonally uniform vertical velocity, zonal wind, horizontal temperature, and vapor advection, as well as sea surface temperature from the Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). The model is also integrated to equilibrium states for 40 days with imposed zero vertical velocity, constant zonal wind, and sea surface temperatures of 31C and 29C for two separate experiments. The time- and zonal-mean surface evaporation mainly comes from rainfall-free regions, where the surface evaporation is largely balanced by the vapor divergence associated with the subsidence. In rainfall regions the vapor convergence determines the convective rainfall while the surface evaporation plays a negligible role. Thus surface evaporation pumps water vapor into rainfall-free regions, and the divergence transports the vapor from rainfall-free regions to rainfall regions, which supports the rainfall. Imposed forcing and sea surface temperature do not change the role of surface evaporation in rainfall processes. |
Dudhia J., 1989: Numerical study of convection observed during the winter monsoon experiment using a mesoscale two-dimensional model. J. Atmos. Sci., 46, 3077- 3107.10.1175/1520-0469(1989)0462.0.CO;2c241bbc0-6ba8-437a-b86c-3796ec18bb1b34a0f338a8622d0aee3c3811d44d3450http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F10013124897refpaperuri:(76536b43084d2ca4dd6ac23f1a23d059)http://ci.nii.ac.jp/naid/10013124897Abstract A two-dimensional version of the Pennsylvania State University mesoscale model has been applied to Winter Monsoon Experiment data in order to simulate the diurnally occurring convection observed over the South China Sea. The domain includes a representation of part of Borneo as well as the sea so that the model can simulate the initiation of convection. Also included in the model are parameterizations of mesoscale ice phase and moisture processes and longwave and shortwave radiation with a diurnal cycle. This allows use of the model to test the relative importance of various heating mechanisms to the stratiform cloud deck, which typically occupies several hundred kilometers of the domain. Frank and Cohen's cumulus parameterization scheme is employed to represent vital unresolved vertical transports in the convective area. The major conclusions are: Ice phase processes are important in determining the level of maximum large-scale heating and vertical motion because there is a strong anvil component. The heating is initiated by a thermodynamic adjustment that takes place after the air leaves the updrafts and is associated with the difference between water and ice saturation. Melting and evaporation contribute to a 1ocalized mesoscale subsidence in a 50 km region to the rear of the moving convective area. The cooling associated with this almost cancels the cumulus heating in the lower to midtroposphere. Radiative heating was found to be the main ascent-forcing influence at high levels occupied by the widespread cirrus outflow. Additionally, radiative clear-air cooling helped the convection by continuously destabilizing the troposphere and countering the warming effect of convective updrafts. The overall structure and development of the system were well simulated, particularly the growth near the coast, and the propagation and decay in the cooler boundary layer further off-shore, but the rainfall may have been underestimated because of the two-dimensional assumptions of the model. |
Gao S. T., X. F. Li, 2008: Cloud-resolving Modeling of Convective Processes. Springer,Dordrecht, 206 pp.10.1007/978-1-4020-8276-40d18fe1b-6fa4-40d6-92b1-81827cfe76d2e76aba2a6b0eff19dd62f432d5595baehttp%3A%2F%2Flink.springer.com%2F978-1-4020-8276-4http://link.springer.com/978-1-4020-8276-4The first book to focuse on cloud-resolving modeling of convective processes, with almost a hundred detailed illustrationsComprehensive information on many research aspects related to convective developmentProvides a thorough description of cloud microphysics and precipitation-radiation interaction Investigates the similarities and differences between two- and three-dimensional cloud-resolving modeling and the future perspective of its application to global domain Gao, Shouting; Li, Xiaofan |
Gao S. T., X. F. Li, 2010: Precipitation equations and their applications to the analysis of diurnal variation of tropical oceanic rainfall. J. Geophys. Res., 115,D08204, doi: 10.1029/2009JD012452.10.1029/2009JD012452c3530c7a-cdcd-4a2a-8c6f-ed65553dece268e59a8da6a9faecd79a1f8c48668ae1http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2F2009JD012452%2Fabstractrefpaperuri:(3e88c4a2018f374840a3f72d731ee64e)http://onlinelibrary.wiley.com/doi/10.1029/2009JD012452/abstractABSTRACT The cloud, water, and heat budgets lay down a foundation for studying relations between precipitation, clouds, and environmental water vapor and thermal conditions. The water vapor constrained precipitation equation is derived by combining cloud budget with water vapor budget, whereas the thermally constrained precipitation equation is derived by combining cloud budget with heat budget. The precipitation equations are applied to analyze the diurnal variations of tropical oceanic rainfall using the 21 day two-dimensional cloud-resolving model simulation during Tropical Ocean-Global Atmosphere Coupled Ocean-Atmosphere Response Experiment and two additional sensitivity experiments. One sensitivity experiment excludes the diurnal variation of large-scale forcing, and the other experiment excludes the diurnal variation of solar zenith angle. The analysis shows that the diurnal variations of water vapor convergence and heat divergence associated with diurnally varying imposed large-scale upward motions play a primary role in the development of rainfall peaks in both afternoon and nighttime, whereas the diurnal variation of radiation is secondary in the formation of nocturnal rainfall peak. The diurnal variation of radiation associated with diurnally varying solar zenith angle determines the diurnal variations of tropical oceanic rainfall when the diurnal variation of large-scale circulation is absent. The diurnal variations of rainfall can be concisely described by simplified diurnally perturbed surface rainfall equations. |
Gao S. T., X. P. Cui, Y. S. Zhou, and X. F. Li, 2005: Surface rainfall processes as simulated in a cloud-resolving model. J. Geophys. Res., 110,D10202, doi: 10.1029/2004JD005467.10.1029/2004JD005467b9b89d40-c143-439a-bac0-b783620dd1430fcbc2115d98f0329481386d6d619f8ehttp://onlinelibrary.wiley.com/doi/10.1029/2004JD005467/pdfhttp://onlinelibrary.wiley.com/doi/10.1029/2004JD005467/pdf[1] Surface rain rate can be simply formulated with the sum of moisture and cloud sources/sinks. In this study the moisture sink comprises the local moisture change, moisture convergence (with an imposed vertical velocity), and surface evaporation, whereas the cloud source/sink comprises the local hydrometeor change since the cyclic boundary condition leads to zero hydrometeor convergence. The sources/sinks and their contributions to the surface rain rate are examined based on hourly zonal mean simulation data from a two-dimensional cloud-resolving model. 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). Although variation in the moisture sink largely accounts for much of the variation in the surface rain rate, the cloud source/sink may modify the surface rain rate significantly. The magnitude of the cloud source/sink increases when the zonal mean surface rain rate increases from 0 to 1 mm h 611 , and it decreases when the rain rate increases from 1 to 2 mm h 611 . The cloud source/sink is further analyzed by breaking it into ice and water hydrometeors. The ice hydrometeors may account for more contributions to the cloud variations than the water hydrometeors, and their growth may lead the surface rain rate by 1–2 hours. |
Gao S. T., X. P. Cui, and X. F. Li, 2009: A modeling study of diurnal rainfall variations during the 21-day period of TOGA COARE. Adv. Atmos. Sci.,26, 895-905, doi: 10.1007/ s00376-009-8123-6.10.1007/s00376-009-8123-6.c0544e02-9ff5-42f6-931a-513ba4dd42444f40c92f0c4ae81fdc368cfaa357c441http%3A%2F%2Fwww.cqvip.com%2FMain%2FDetail.aspx%3Fid%3D31761426refpaperuri:(45a597196dc458e47ce02cddddc04756)http://d.wanfangdata.com.cn/Periodical_dqkxjz-e200905007.aspxThe 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. |
Grabowski W. W., X. Q. Wu, M. W. Moncrieff, and W. D. Hall, 1998: Cloud-resolving model of tropical cloud systems during Phase III of GATE. Part II: Effects of resolution and the third spatial dimension. J. Atmos. Sci., 55, 3264- 3282.10.1175/1520-0469(1998)0552.0.CO;2f159c9fe-ee9b-4966-b695-36fac4db1caa17b5133f6da4ec44c5b6b79aeb9e9393http://ci.nii.ac.jp/naid/80010729053http://ci.nii.ac.jp/naid/80010729053Abstract Two- and three-dimensional simulations of cloud systems for the period of 17 September 1974 in phase III of the Global Atmospheric Research Programme (GARP) Atlantic Tropical Experiment (GATE) are performed using the approach discussed in Part I of this paper. The aim is to reproduce cloud systems over the GATE B-scale sounding array. Comparison is presented between three experiments driven by the same large-scale conditions: (i) a fully three-dimensional experiment, (ii) a two-dimensional experiment that is an eastest section of the three-dimensional case, and (iii) a high-resolution version of the two-dimensional experiment. Differences between two- and three-dimensional frameworks and those related to spatial resolution are analyzed. The three-dimensional experiment produced a qualitatively realistic organization of convection: nonsquall clusters, a squall line, and scattered convection and transitions between regimes were simulated. The two-dimensional experiments produced convective organization similar to that discussed in Part I. The thermodynamic fields evolved very similarly in all three experiments, although differences between model fields and observations did occur. When averaged over a few hours, surface sensible and latent heat fluxes and surface precipitation evolved very similarly in all three experiments and evaluated well against observations. Model resolution had some effect on the upper-troposheric cloud cover and consequently on the upper-tropospheric temperature tendency due to radiative flux divergence. When compared with the fully three-dimensional results, the two-dimensional simulations produced a much higher temporal variability of domain-averaged quantities. The results support the notion that, as long as high-frequency temporal variability is not of primary importance, low-resolution two-dimensional simulations can be used as realizations of tropical cloud systems in the climate problem and for improving and/or testing cloud parameterizations for large-scale models. |
Gray W. M., R. W. Jacobson Jr., 1977: Diurnal variation of deep cumulus convection. Mon. Wea. Rev., 105, 1171- 1188.10.1175/1520-0493(1977)1052.0.CO;26c58ccbc-207c-4f25-961b-96055aa782ceabe38cdb1d371b2c204871fddfb5fea8http%3A%2F%2Fci.nii.ac.jp%2Fnaid%2F80014791079refpaperuri:(d022562855cb43b82ad1175d4201bdda)http://ci.nii.ac.jp/naid/80014791079Abstract This paper presents observational evidence in support of the existence of a large diurnal cycle (one daily maximum and one daily minimum) of oceanic, tropical, deep cumulus convection. The more intense the deep convection and the more associated it is with organized weather systems, the more evident is a diurnal cycle with a maximum in the morning. At many places heavy rainfall is 23 times greater in the morning than in the late afternoon-evening. Many land stations also show morning maxima of heavy rainfall. The GATE observations show a similar diurnal range in heavy rainfall, but the time of maximum occurrence is in the afternoon. This occurrence is 67 h later than in most other oceanic regions and is probably a result of downwind influences from Africa and the fact that the GATE heavy rainfall was often associated with squall lines. Diurnal variations in low-level, layered and total cloudiness show a much smaller range. The variability of deep convection and heavy rainfall is not readily observable from those satellite pictures which cannot well resolve individual convective cells nor is it easily obtained from surface observations of the percent of sky coverage which are heavily weighted to the presence of low-level and layered clouds. A comparison of previous observational studies is made. It is hypothesized that the diurnal cycle in deep convection with a morning maximum is associated with organized weather disturbances. This diurnal cycle likely results from day versus night variations in tropospheric radiational cooling between the weather system and its surrounding cloud-free region. |
Khairoutdinov M. F., D. A. Randall, 2003: Cloud-resolving modeling of the ARM summer 1997 IOP: Model formulation, results, uncertainties, and sensitivities. J. Atmos.Sci., 60, 607- 625.10.1175/1520-0469(2003)0602.0.CO;23922ac8f-17ea-488c-86a0-de59fcebf117144e3a9424f1ea6e14aa9494b91a53f5http://ci.nii.ac.jp/naid/80015796553http://ci.nii.ac.jp/naid/80015796553Abstract A new three-dimensional cloud resolving model (CRM) has been developed to study the statistical properties of cumulus convection. The model was applied to simulate a 28-day evolution of clouds over the Atmospheric Radiation Measurement Program (ARM) Southern Great Plains site during the summer 1997 Intensive Observation Period. The model was forced by the large-scale advective tendencies and surface fluxes derived from the observations. The sensitivity of the results to the domain dimensionality and size, horizontal grid resolution, and parameterization of microphysics has been tested. In addition, the sensitivity to perturbed initial conditions has also been tested using a 20-member ensemble of runs. The model captures rather well the observed temporal evolution of the precipitable water and precipitation rate, although it severely underestimates the shaded cloud fraction possibly because of an inability to account for the lateral advection of clouds over the ARM site. The ensemble runs reveal that the uncertainty of the simulated precipitable water due to the fundamental uncertainty of the initial conditions can be as large as 25% of the mean values. Even though the precipitation rates averaged over the whole simulation period were virtually identical among the ensemble members, the timing uncertainty of the onset and reaching the precipitation maximum can be as long as one full day. Despite the predictability limitations, the mean simulation statistics are found to be almost insensitive to the uncertainty of the initial conditions. The overall effects of the third spatial dimension are found to be minor for simulated mean fields and scalar fluxes but are quite considerable for velocity and scalar variances. Neither changes in a rather wide range of the domain size nor the horizontal grid resolution have any significant impact on the simulations. Although a rather strong sensitivity of the mean hydrometeor profiles and, consequently, cloud fraction to the microphysics parameters is found, the effects on the predicted mean temperature and humidity profiles are shown to be modest. It is found that the spread among the time series of the simulated cloud fraction, precipitable water, and surface precipitation rate due to changes in the microphysics parameters is within the uncertainty of the ensemble runs. This suggests that correlation of the CRM simulations to the observed long time series of the aforementioned parameters cannot be generally used to validate the microphysics scheme. |
Krueger S. K., Q. Fu, K. N. Liou, and H.-N. S. Chin, 1995: Improvement of an ice-phase microphysics parameterization for use in numerical simulations of tropical convection. J. Appl. Meteor., 34, 281- 287. |
Li X. F., S. T. Gao, 2011: Precipitation Modeling and Quantitative Analysis. Springer,Dordrecht, 240 pp.10.1007/978-94-007-2381-8f24e7927-9aaa-4d35-9a65-65b7a517032ae5bf40ca3f1c52c208260310236b78bchttp%3A%2F%2Flink.springer.com%2F978-94-007-2381-8refpaperuri:(e325017cdff17cac5f7d04bd3472e326)http://link.springer.com/978-94-007-2381-8The book examines surface rainfall processes through cloud-resolving modeling and quantitative analysis of surface rainfall budget and summarizes modeling and analysis results in recent seven years. The book shows validation of precipitation modeling against observations and derives a set of diagnostic precipitation equations. The book provides detailed discussions of the applications of precipitation equations to the examination of effects of sea surface temperature, vertical wind shear, radiation, and ice clouds on torrential rainfall processes in the tropics and mid-latitudes, and to the studies of sensitivity of precipitation modeling to uncertainty of the initial conditions and to the estimate of precipitation efficiency. The book can be used as a text book for graduate students and will be beneficial to researchers and forecasters for precipitation process studies and operational forecasts.Xiaofan Li is a physical scientist at the Center for Satellite Applications and Research, National Environmental Satellite, Data, and Information Service, National Oceanic and Atmospheric Administration, Camp Springs, Maryland, USA. He has a doctorate in meteorology from the University of Hawaii at Manoa, Honolulu, USA and a master s degree in meteorology from Nanjing University of Information Science and Technology, Nanjing, China.Shouting Gao is a professor at the Laboratory of Cloud-Precipitation Physics and Severe Storm, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China. He has a doctorate and a master s degree in meteorology from the Institute of Atmospheric Physics, Beijing, China. |
Li X. F., C.-H. Sui, K.-M. Lau, and M.-D. Chou, 1999: Large-scale forcing and cloud-radiation interaction in the tropical deep convective regime. J. Atmos. Sci., 56, 3028- 3042.10.1175/1520-0469(1999)0562.0.CO;2dd4dd2e9-5de3-4115-8b77-e49fa7c7ab229e1e7d53a7c70f78c50d58ec678c7dd7http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F237967176_Large-Scale_Forcing_and_CloudRadiation_Interaction_in_the_Tropical_Deep_Convective_Regimerefpaperuri:(6b5189fc7a182e14a1346de1396379dd)http://www.researchgate.net/publication/237967176_Large-Scale_Forcing_and_CloudRadiation_Interaction_in_the_Tropical_Deep_Convective_RegimeDetails a study which carried out the simulations of tropical convection and thermodynamic states in response to different imposed large-scale forcing by using a cloud-resolving model. Experimental designs; Comparison between the control experiment and observations; Results and discussion. |
Li X. F., C.-H. Sui, and K.-M. Lau, 2002: Dominant cloud microphysical processes in a tropical oceanic convective system: A 2-D cloud resolving modeling study. Mon. Wea. Rev., 130, 2481- 2491.10.1175/1520-0493(2002)130<2481:DCMPIA>2.0.CO;2e7805570-512e-463c-a7bc-12b6c266d2fef6f8c79a87987fc4246ba6c2caeb81a6http://www.researchgate.net/publication/240689103_Dominant_Cloud_Microphysical_Processes_in_a_Tropical_Oceanic_Convective_System_A_2D_Cloud_Resolving_Modeling_Studyhttp://www.researchgate.net/publication/240689103_Dominant_Cloud_Microphysical_Processes_in_a_Tropical_Oceanic_Convective_System_A_2D_Cloud_Resolving_Modeling_StudyABSTRACT |
Li X. F., G. Q. Zhai, S. T. Gao, and X. Y. Shen, 2014: A new convective-stratiform rainfall separation scheme. Atmos. Sci. Lett., 15, 245- 251.f9316850-b736-4d3f-a88b-2f965c2f347a16b907c2afa66e80543dbbf6c3105a8ahttp://onlinelibrary.wiley.com/resolve/doi?DOI=10.1002%2Fasl2.493/s?wd=paperuri%3A%2819b58e024220a686abeee3b7fe0efd44%29&filter=sc_long_sign&sc_ks_para=q%3DA%20new%20convective%E2%80%93stratiform%20rainfall%20separation%20scheme&tn=SE_baiduxueshu_c1gjeupa&ie=utf-8 |
Li X. F., G. Q. Zhai, P. J. Zhu, and R. Liu, 2015: An equilibrium cloud-resolving modeling study of diurnal variation of tropical rainfall. Dyn. Atmos.Ocean, 71, 108- 117.10.1016/j.dynatmoce.2015.07.001b468585b-5bf0-453b-bef2-d0db9a0ff9d42d3386f343de2716fc19a4eae7c3eb79http%3A%2F%2Fwww.sciencedirect.com%2Fscience%2Farticle%2Fpii%2FS0377026515000329http://www.sciencedirect.com/science/article/pii/S0377026515000329The diurnal variation of tropical rainfall is examined through the analysis of an equilibrium cloud-resolving model experiment. Model domain mean rain rate is defined as a product of rain intensity and fractional rainfall coverage. The diurnal variation of the mean rain rate is associated with that of fractional rainfall coverage because the diurnal variation of rain intensity is significantly weakened through the decrease in rainfall in early morning hours. The decrease in rainfall corresponds to the reduction in secondary circulations through the barotropic conversion from the perturbation kinetic energy to the mean kinetic energy under the imposed negative vertical gradient of westerly winds. The fractional rainfall coverage shows the diurnal signal with the maximum in the early morning hours primarily due to nocturnal infrared radiative cooling. |
Lilly D. K., 1988: Cirrus outflow dynamics. J. Atmos. Sci., 45, 1594- 1605.34afb10f-82fe-4427-8365-992754c936bee4c5382c5ab813b69c2c002857e0ecc8http://journals.ametsoc.org/doi/abs/10.1175/1520-0469(1988)045<1594:COD>2.0.CO%3B2/s?wd=paperuri%3A%2824c18935cb1713524dbd556cf3895ae6%29&filter=sc_long_sign&sc_ks_para=q%3DCirrus%20Outflow%20Dynamics&tn=SE_baiduxueshu_c1gjeupa&ie=utf-8 |
Lin Y.-L., R. D. Farley, and H. D. Orville, 1983: Bulk parameterization of the snow field in a cloud model. J. Climate Appl. Meteor., 22, 1065- 1092. |
Ping F., Z. Luo, and H. Wang, 2011: Effects of ice and water clouds on rainfall: A partitioning analysis based on surface rainfall budget. Atmos. Sci. Lett., 12, 300- 308.10.1002/asl.340bfe75604-ff48-4c33-b12b-db307f436f51f2e3969b9ccdd0fb2284dc7fe62a3d74http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fasl.340%2Fabstractrefpaperuri:(612ca73c3ad70e5fc2283e8a9b3ee6cf)http://onlinelibrary.wiley.com/doi/10.1002/asl.340/abstractABSTRACT The effects of ice and water clouds on rainfall are investigated through a partitioning analysis based on surface rainfall budget. The data come from five two-dimensional idealized cloud-resolving model simulations that are imposed by zero large-scale vertical velocity and time-invariant sea surface temperature. The grid-scale rainfall simulation data from the last 10-day equilibrium period are categorized by different rainfall processes to form eight rainfall types. The results show that the rainfall contribution of the rainfall with water vapor convergence is decreased when the radiative effects of ice and water clouds are excluded, whereas it is increased when the microphysical effects of ice clouds are excluded. The decreased rainfall contribution caused by the removal of radiative effects of ice clouds is much stronger than that caused by the elimination of radiative effects of water clouds, whereas it is weaker than the increased rainfall contribution caused by the exclusion of microphysical effects of ice clouds, which leads to the increased rainfall contribution caused by the total exclusion of ice microphysics. Copyright 2011 Royal Meteorological Society |
Rutledge S. A., P. V. Hobbs, 1983: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part VIII: A model for the "seeder-feeder" process in warm-frontal rainbands. J. Atmos. Sci., 40, 1185- 1206.10.1175/1520-0469(1983)0402.0.CO;2e97fe16e-f0e1-43d2-b50a-c94cd3c365db4a5e3ec756c6dbd47ea03c01fad32f7dhttp://ci.nii.ac.jp/naid/10013127369/http://ci.nii.ac.jp/naid/10013127369/Abstract Previous field studies have indicated that warm-frontal rainbands form when ice particles from a “seeder” cloud grow as they fall through a lower-level “feeder” cloud. In this paper we present results from a parameterized numerical model of the growth processes that can lead to the enhancement of precipitation in a “seeder-feeder” type situation. The model is applied to two types of warm-frontal rainbands. In the first (Type 1 situation) the vertical air motions are typical of those associated with slow, widespread lifting in the vicinity of warm fronts. In the second (Type 2 situation) the vertical air motions are stronger, and more characteristic of the mesoscale. The model simulations show that in the Type 1 situations the growth of the “seed” ice crystals within the feeder zone is due to vapor deposition. The feeder zone in this case is slightly sub-saturated with respect to water due to the presence of the seed crystals. In regions where the feeder zone is not “seeded” from aloft, snow crystals, originating in the feeder zone, grow by deposition and riming and produce a precipitation rate of 651 mm h 611 , compared to 652 mm h 611 for the combined seeder-feeder cloud system. The presence of seed crystals allows for the efficient removal of condensation produced by the feeder cloud. In the Type 2 situation, the strong mesoscale ascent provides liquid water from which the seed crystals grow primarily by riming. For both Type 1 and 2 situations the condensation rates, radar reflectivities and rainfall rates predicted by the model are in reasonable agreement with field observations. |
Rutledge S. A., P. V. Hobbs, 1984: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XII: A diagnostic modeling study of precipitation development in narrow cold-frontal rainbands. J. Atmos. Sci., 41, 2949- 2972. |
Soong S. T., Y. Ogura, 1980: Response of tradewind cumuli to large-scale processes. J. Atmos. Sci., 37, 2035- 2050.10.1175/1520-0469(1980)037<2035:ROTCTL>2.0.CO;2ff29183f-0c94-40ab-a743-344ed26775f0b7378c22aa84e357b292f1c0c7b03256http://www.researchgate.net/publication/234192515_Response_of_Tradewind_Cumuli_to_Large-Scale_Processeshttp://www.researchgate.net/publication/234192515_Response_of_Tradewind_Cumuli_to_Large-Scale_ProcessesABSTRACT The 2-dimensional slab-symmetric numerical cloud model for studying the evolution of an isolated cumulus cloud is extended to investigate the statistical properties of cumulus clouds which would be generated under a given large-scale forcing composed of the horizontal advection of temperature and water vapor mixing ratio, vertical velocity, sea surface temperature and radiative cooling. The model is applied to a case of suppressed weather conditions during BOMEX for the period 22-23 June 1969 when a nearly steady state prevailed. -from Authors |
Soong S. T., W.-K. Tao, 1980: Response of deep tropical cumulus clouds to Mesoscale processes. J. Atmos. Sci., 37, 2016- 2034.10.1175/1520-0469(1980)0372.0.CO;2d11e8964-c64f-415a-be4b-615b1f4ce6509cb2afe5e74b2575cdebc09c8082d7bfhttp%3A%2F%2Fwww.researchgate.net%2Fpublication%2F237966950_Response_of_Deep_Tropical_Cumulus_Clouds_to_Mesoscale_Processesrefpaperuri:(0bd9ba2116c04e1b0401e5e152555845)http://www.researchgate.net/publication/237966950_Response_of_Deep_Tropical_Cumulus_Clouds_to_Mesoscale_ProcessesAbstract The two-dimensional cloud ensemble model developed by Soong and Ogura (1980) is used to simulate the response of deep clouds to mesoscale lifting using data obtained in the Global Atmospheric Research Program (GARP) Atlantic Tropical Experiment (GATE). The input to the model includes the mesoscale vertical velocity, horizontal advections of temperature and mixing ratio of water vapor, radiative cooling and sea surface temperature. The cloud ensemble feedback effects due to the condensation and evaporation of cloud liquid drops and vertical fluxes of heat and moisture are determined by the model. The simulated upward mass flux inside the model clouds is about three times the mass flux due to mesoscale lifting. The downward mass flux inside clouds is also large, leaving a small downward mass flux in the cloud-free area. The major portion of the heat flux is produced by the updraft inside clouds. On the other hand, the moisture fluxes due to both updraft and downdraft are important. In the cloud-free area, the heat and moisture fluxes are both small due to the small mass flux in that area. Experiments with different magnitudes of mesoscale lifting generate different sizes of clouds and different cloud heating and moistening profiles. However, in each simulation, the changes of temperature and mixing ratio due to mesoscale processes are almost balanced by the cloud heating and drying effects, leaving only small temporal changes in the horizontal mean temperature and mixing ratio. In a simulation with only low-level lifting, a warming is generated in the middle levels. This warming can be important in producing higher level vertical lifting, which in turn could produce even higher clouds. |
Sui C.-H., K.-M. Lau, W.-K. Tao, and J. Simpson, 1994: The tropical water and energy cycles in a cumulus ensemble model. Part I: Equilibrium climate. J. Atmos. Sci., 51, 711- 728.10.1175/1520-0469(1994)0512.0.CO;286b7b464-a4c5-442a-a0bd-2ab2bd5b10e69f796b7d91f49f15c2596dd8f4a3020chttp%3A%2F%2Fwww.researchgate.net%2Fpublication%2F252505148_The_Tropical_Water_and_Energy_Cycles_in_a_Cumulus_Ensemble_Model._Part_I_Equilibrium_Climaterefpaperuri:(5cbbdc8b420d7a9d87783a0e0c572e7a)http://www.researchgate.net/publication/252505148_The_Tropical_Water_and_Energy_Cycles_in_a_Cumulus_Ensemble_Model._Part_I_Equilibrium_ClimateAbstract A cumulus ensemble model is used to study the tropical water and energy cycles and their role in the climate system. The model includes cloud dynamics, radiative processes, and microphysics that incorporate all important production and conversion processes among water vapor and five species of hydrometeors. Radiative transfer in clouds is parameterized based on cloud contents and size distributions of each bulk hydrometeor. Several model integrations have been carried out under a variety of imposed boundary and large-scale conditions. In Part I of this paper, the primary focus is on the water and heat budgets of the control experiment, which is designed to simulate the convective adiative equilibrium response of the model to an imposed vertical velocity and a fixed sea surface temperature at 28C. The simulated atmosphere is conditionally unstable below the freezing level and close to neutral above the freezing level. The equilibrium water budget shows that the total moisture source, M s , which is contributed by surface evaporation (0.24 M s ) and the large-scale advection (0.76 M s ), all converts to mean surface precipitation P s . Most of M s is transported vertically in convective regions where much of the condensate is generated and falls to surface (0.68 P s ). The remaining condensate detrains at a rate of 0.48 P s and constitutes 65% of the source for stratiform clouds above the melting level. The upper-level stratiform cloud dissipates into clear environment at a rate of 0.14 P s , which is a significant moisture source comparable to the detrained water vapor (0.15 P s ) to the upper troposphere from convective clouds. In the lower troposphere, stratiform clouds evaporate at a rate of 0.41 P s , which is a more dominant moisture source than surface evaporation (0.22 P s ). The precipitation falling to the surface in the stratiform region is about 0.32 P s . The associated latent heating in the water cycle is the dominant source in the heat budget that generates a net upward motion in convective regions, upper stratiform regions (above the freezing level), and a downward motion in the lower stratiform regions. The budgets reveal a cycle of water and energy resulted from radiation ynamiconvection interactions that maintain the equilibrium of the atmosphere. |
Sui C.-H., K.-M. Lau, Y. N. Takayabu, and D. Short, 1997: Diurnal variations in tropical oceanic cumulus convection during TOGA COARE. J. Atmos. Sci., 54, 639- 655.10.1175/1520-0469(1997)0542.0.CO;2a7714c49-ca31-4a50-a186-760d038d6e276e2940b8a9c57a212c9b3059f906d072http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F254314603_Diurnal_Variations_in_Tropical_Oceanic_Cumulus_Convection_during_TOGA_COARErefpaperuri:(78b9ea907260c412ba79431e314d5890)http://www.researchgate.net/publication/254314603_Diurnal_Variations_in_Tropical_Oceanic_Cumulus_Convection_during_TOGA_COAREAbstract Diurnal variations in atmospheric convection, dynamic/thermodynamic fields, and heat/moisture budgets over the equatorial Pacific warm pool region are analyzed based on data collected from different observation platforms during the Intensive Observation Period of the Tropical Ocean Global Atmosphere Coupled Oceantmosphere Response Experiment (TOGA COARE). Results reveal that the diurnal variations in rainfall/convection over the TOGA COARE region can be classified into three distinct stages: warm morning cumulus, afternoon convective showers, and nocturnal convective systems. Afternoon rainfall comes mostly from convective cells, but the nocturnal rainfall is derived from deeper convective cells and large areas of stratiform clouds. Results further show that afternoon convective showers are more evident in the large-scale undisturbed periods when the diurnal SST cycle is strong, but the nocturnal convective systems and morning cumulus are more enhanced in the disturbed periods when more moisture is available. The primary cause of the nocturnal rainfall maximum is suggested to be associated with more (less) available precipitable water in the night (day) due to the diurnal radiative cooling/heating cycle and the resultant change in tropospheric relative humidity. |
Sui C.-H., X. Li, and K.-M. Lau, 1998: Radiative-convective processes in simulated diurnal variations of tropical oceanic convection. J. Atmos. Sci., 55, 2345- 2359.10.1175/1520-0469(1998)055<2345:RCPISD>2.0.CO;2184a7427-712a-4928-b165-1f3ed1902f43a5659bebf87700e06fd5f4843658e1echttp://www.researchgate.net/publication/249609844_RadiativeConvective_Processes_in_Simulated_Diurnal_Variations_ofTropical_Oceanic_Convectionhttp://www.researchgate.net/publication/249609844_RadiativeConvective_Processes_in_Simulated_Diurnal_Variations_ofTropical_Oceanic_ConvectionPresents an analysis of the diurnal variation of tropical oceanic convection and its association with the energy cycle as simulated by an anelastic cumulus ensemble model. Observations of studies conducted on diurnal variations; Reference to the application of the cumulus ensemble model; Information on the diurnal variations of convection. |
Sui C.-H., X. F. Li, M.-J. Yang, and H.-L. Huang, 2005: Estimation of oceanic precipitation efficiency in cloud models. J. Atmos. Sci., 62, 4358- 4370.10.1175/JAS3587.1e69ed9dc-27b7-4322-950b-6d63bd7767bcf77fec6ac2416526f1eb6fd5d0188d54http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F255608256_Estimation_of_Oceanic_Precipitation_Efficiency_in_Cloud_Modelsrefpaperuri:(bbff2294b288fa300f4b352bc1d6a58b)http://www.researchgate.net/publication/255608256_Estimation_of_Oceanic_Precipitation_Efficiency_in_Cloud_ModelsAbstract Precipitation efficiency is estimated based on vertically integrated budgets of water vapor and clouds using hourly data from both two-dimensional (2D) and three-dimensional (3D) cloud-resolving simulations. The 2D cloud-resolving model is forced by the vertical velocity derived from the Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE). The 3D cloud-resolving modeling is based on the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) simulation of Typhoon Nari (in 2001). The analysis of the hourly moisture and cloud budgets of the 2D simulation shows that the total moisture source (surface evaporation and vertically integrated moisture convergence) is converted into hydrometeors through vapor condensation and deposition rates regardless of the area size where the average is taken. This leads to the conclusion that the large-scale and cloud-microphysics precipitation efficiencies are statistically equivalent. Results further show that convergence (divergence) of hydrometeors would make precipitation efficiency larger (smaller). The precipitation efficiency tends to be larger (even >100%) in light rain conditions as a result of hydrometeor convergence from the neighboring atmospheric columns. Analysis of the hourly moisture and cloud budgets of the 3D results from the simulation of a typhoon system with heavy rainfall generally supports that of 2D results from the simulation of the tropical convective system with moderate rainfall intensity. |
Tao W. K., S. T. Soong, 1986: A study of the response of deep tropical clouds to mesoscale processes: Three-dimensional numerical experiments. J. Atmos. Sci., 43, 2653- 2676.10.1175/1520-0469(1986)043<2653:ASOTRO>2.0.CO;20cb05007-90d2-4c6c-95f0-296ee3ebca2e36bbfe251e7362aa28e09b115e235fddhttp%3A%2F%2Fwww.researchgate.net%2Fpublication%2F4699667_A_Study_of_the_Response_of_Deep_Tropical_Clouds_to_Mesoscale_Processes_Three-Dimensional_Numerical_Experimentsrefpaperuri:(35e71f418b1822b8dad1f6d90b82742a)http://www.researchgate.net/publication/4699667_A_Study_of_the_Response_of_Deep_Tropical_Clouds_to_Mesoscale_Processes_Three-Dimensional_Numerical_ExperimentsABSTRACT |
Tao W.-K., J. Simpson, 1993: The Goddard Cumulus Ensemble model. Part I: Model description. Terrestrial Atmospheric and Oceanic Sciences, 4, 35- 72.8e5bceb8-78c9-488f-8acf-adba7bb88978b417f193e1eefd01520a624a1f786ec2http://www.researchgate.net/publication/216681389_Goddard_cumulus_ensemble_model._Part_I_Model_descriptionhttp://www.researchgate.net/publication/216681389_Goddard_cumulus_ensemble_model._Part_I_Model_descriptionABSTRACT During the past two decades, convective scale models have advanced sufficiently to study the dynamic and microphysical proassociated with mesoscale convective systems. The basic features of these models are that they are non-hydrostatic |
Tao W.-K., J. Simpson, and S.-T. Soong, 1987: Statistical properties of a cloud ensemble: A numerical study. J. Atmos. Sci., 44, 3175- 3187.10.1175/1520-0469(1987)044<3175:SPOACE>2.0.CO;2be09eab1-f71e-4af3-a16a-8a35469d28d150d14f563170dd0d5ec7af05faa19eaahttp%3A%2F%2Fwww.researchgate.net%2Fpublication%2F23703540_Statistical_Properties_of_a_Cloud_Ensemble_A_Numerical_Studyrefpaperuri:(9502e5f483ec8ff58cd8029c4df3cbbe)http://www.researchgate.net/publication/23703540_Statistical_Properties_of_a_Cloud_Ensemble_A_Numerical_StudyABSTRACT The statistical properties of cloud ensembles under a specified large-scale environment, such as mass flux by cloud drafts and vertical velocity as well as the condensation and evaporation associated with these cloud drafts, are examined using a three-dimensional numerical cloud ensemble model described by Soong and Ogura (1980) and Tao and Soong (1986). The cloud drafts are classified as active and inactive, and separate contributions to cloud statistics in areas of different cloud activity are then evaluated. The model results compare well with results obtained from aircraft measurements of a well-organized ITCZ rainband that occurred on August 12, 1974, during the Global Atmospheric Research Program's Atlantic Tropical Experiment. |
Tao, W.-K, J. Simpson, M. McCumber, 1989: An ice-water saturation adjustment. Mon. Wea. Rev., 117, 231- 235.10.1175/1520-0493(1989)117<0231:AIWSA>2.0.CO;20f4f0e12-3f6a-4a84-9606-c5add887802dfee2540886c2687f05a94463c961cc2ahttp://www.researchgate.net/publication/24150547_An_ice-water_saturation_adjustmenthttp://www.researchgate.net/publication/24150547_An_ice-water_saturation_adjustmentABSTRACT A reasonably accurate and noniterative saturation adjustment scheme is proposed to calculate: (1) the amount of condensation and/or deposition necessary to remove any supersaturated vapor, or (2) the amount of evaporation and/or sublimation necessary to remove any subsaturation in the presence of cloud droplets and/or cloud ice. This proposed scheme can be implemented for a nonhydrostatic cloud model. The derivation of the scheme, an evaluation of its performance, and tests for sensitivity to variations in a few key parameters are presented. |
Tao W. K., J. Simpson, C. H. Sui, B. Ferrier, S. Lang, J. Scala, M. D. Chou, and K. Pickering, 1993: Heating, moisture, and water budgets of tropical and midlatitude squall lines: Comparisons and sensitivity to longwave radiation. J.Atmos. Sci., 50, 673- 690.10.1175/1520-0469(1993)0502.0.CO;2bdd2845e-19f8-43c6-a758-7b51a52908af8efc53f569af8e6d157ee81c5eafe3behttp://www.researchgate.net/publication/23601904_Heating_moisture_and_water_budgets_of_tropical_and_midlatitude_squall_lines_-_Comparisons_and_sensitivity_to_longwave_radiationhttp://www.researchgate.net/publication/23601904_Heating_moisture_and_water_budgets_of_tropical_and_midlatitude_squall_lines_-_Comparisons_and_sensitivity_to_longwave_radiationAbstract A two-dimensional, time-dependent, and nonhydrostatic numerical cloud model is used to estimate the heating ( Q 1 , moisture ( Q 2 ), and water budgets in the convective and stratiform regions for a tropical and a midlatitude squall line (EMEX and PRE-STORM). The model is anelastic and includes a parameterized three-class ice-phase microphysical scheme and longwave radiative transfer processes. A quantitative estimate of the impact of the longwave radiative cooling on the total surface precipitation as well as on the development and structure of these two squall lines is presented. It was found that the vertical eddy moisture fluxes are a major contribution to the model-derived Q 2 budgets in both squall cases. A distinct midlevel minimum in the Q 2 profile for the EMEX case is due to vertical eddy transport in the convective region. On the other hand, the contribution to the Q 1 budget by the cloud-scale fluxes is minor for the EMEX case. In contrast, the vertical eddy heat flux is relatively important for the PRE-STORM case due to the stronger vertical velocities present in the PRE-STORM convective cells. It was found that the convective region plays an important role in the generation of stratiform rainfall for both cases. Although the EMEX case has more stratiform rainfall than its PRE-STORM counterpart, the relative contribution to the stratiform water budget made by the horizontal transfer of hydrometeors from the convective region is less. But the transfer of condensate from the convective region became relatively less important with time in the stratiform water budget of the PRE-STORM system as it developed from its initial stage, such that the relative contribution to the stratiform water budget made by the horizontal transfer of hydrometeors from the convective region is similar at the mature stages of both systems. Longwave radiative cooling enhanced the total surface precipitation about 14% and 31% over a 16-h simulation time for the PRE-STORM and EMEX cases, respectively. The relative contribution to the stratiform water budget from the convective region is, however, more sensitive to the longwave radiative cooling for the PRE-STORM case than for the EMEX case. These results are due to the relatively moist environment and comparatively earlier development of the stratiform cloud in the EMEX squall system. Nevertheless, the effect of radiative cooling is shown to increase as systems age in both cases. It was also determined that the Q 1 and Q 2 budgets in the convective and stratiform regions are only quantitatively, not qualitatively, altered by the inclusion or exclusion of longwave radiative transfer processes. |
Tompkins A. M., 2000: The impact of dimensionality on long-term cloud-resolving model simulations. Mon. Wea. Rev., 128, 1521- 1535.10.1175/1520-0493(2000)1282.0.CO;2becc2745-b5d6-4b07-9fe2-e7ccabea55f8c50471a5d09110f198f41d90dfbd83b3http%3A%2F%2Fwww.researchgate.net%2Fpublication%2F242096670_The_Impact_of_Dimensionality_on_Long-Term_Cloud-Resolving_Model_Simulationsrefpaperuri:(400ebfec42d75d8429bcde92a5139b54)http://www.researchgate.net/publication/242096670_The_Impact_of_Dimensionality_on_Long-Term_Cloud-Resolving_Model_SimulationsAbstract Cloud-resolving model simulations of radiative onvective equilibrium are conducted in both two and three dimensions (2D and 3D) to examine the effect of dimensionality on the equilibrium statistics. Convection is forced by a fixed imposed profile of radiative cooling and surface fluxes from fixed temperature ocean. In the control experiment, using the same number of grid points in both 2D and 3D and a zero mean wind, the temperature and moisture profiles diverge considerably after a few days of simulations. Two mechanisms are shown to be responsible for this. First, 2D geometry causes higher perturbation surface winds resulting from deep convective downdrafts, which lead to a warmer, moister boundary layer and a warmer tropospheric mean temperature state. Additionally, 2D geometry encourages spontaneous large-scale organization, in which areas far away from convection become very dry and thus inhibit further convection there, leading to a drier mean atmosphere. Further experiments were conducted in which horizontal mean winds were applied, adopting both constant and sheared vertical profiles. With mean surface winds that are of the same magnitude as downdraft outflow velocities or greater, convection can no longer increase mean surface fluxes, and the temperature differences between 2D and 3D are greatly reduced. However, the organization of convection still exists with imposed wind profiles. Repeating the experiments on a small 2D domain produced similar equilibrium profiles to the 3D investigations, since the limited domain artificially reduces surface wind speeds, and also restricts mesoscale organization. The main conclusions are that for modeling convection that is highly two-dimensionally organized, such as squall lines or Walker-type circulations over strong SST gradients, and for which a reasonable mean surface wind exists, it is possible that a 2D model can be used. However, for random or clustered convection, and especially in low wind environments, it is highly preferable to use a 3D cloud model. |