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研究生:吳佳瑩
研究生(外文):Jia-Ying Wu
論文名稱:海洋性低雲於不同環境下之特性
論文名稱(外文):Characteristics of Marine Low Clouds Under Various Environmental Conditions
指導教授:郭鴻基郭鴻基引用關係吳健銘
指導教授(外文):Hung-Chi KuoChien-Ming Wu
口試委員:陳維婷蘇世顥
口試委員(外文):Wei-Ting ChenShih-Hao Su
口試日期:2017-03-20
學位類別:碩士
校院名稱:國立臺灣大學
系所名稱:大氣科學研究所
學門:自然科學學門
學類:大氣科學學類
論文種類:學術論文
論文出版年:2017
畢業學年度:105
語文別:中文
論文頁數:56
中文關鍵詞:海洋性低雲雲型轉換層積雲底下積雲液態水路徑
外文關鍵詞:marine low cloudcloud structure transitioncumulus-under-stratocumulusliquid water path
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本研究旨在探討數值理想模式中,海洋性低雲由副熱帶往赤道方向移行時之雲型轉變現象。利用三維向量渦度方程雲解析模式(Vector Vorticity equation cloud-resolving Mode,VVM)模擬東北太平洋海域海洋性低雲由層雲型態轉變至對流胞型態。控制實驗中,海表面溫度增加與大尺度沉降減少等條件以拉格朗日(Lagrangian)軌跡所經過的環境來調整;另外,敏感度實驗則改變邊界層頂之上自由大氣與邊界層內的總水混和比差值(〖-∆q〗_t)及液態水位溫差值(〖∆θ〗_l),討論水氣含量差異及逆溫強度對於海洋性邊界層低雲雲型轉換期間特性的影響。
控制實驗之模式環境場初始設定為:-∆q_t=6.34 g kg-1;〖∆θ〗_l=11.16 K,發現在模式內雲型會發展為具有較強對流胞的淺積雲與在邊界層頂的層積雲共存的邊界層型態。根據液態水路徑(Liquid Water Path,LWP)的機率密度函數(Probability Density Function,PDF)分析,邊界層內層雲在模式模擬約45分鐘後破裂,並於約三個半小時後轉為層積雲底下積雲型態。當增加〖-∆q〗_t時,邊界層內的低雲會提前破裂,也越早發展出對流胞:若-∆q_t增加(減少)2.00 g kg-1,則從自由大氣向下逸入的空氣變得更為乾燥(潮濕),邊界層內層雲破裂提前(延後)約35分鐘(1小時20分鐘);形成層積雲底下積雲型態提前(延後)約1小時50分鐘(6小時25分鐘)。
倘若降低∆θ_l,使得邊界層頂的逆溫減弱,邊界層內的海洋性低雲迅速發展為對流胞結構,在〖∆θ〗_l減小4.98 K的情況下,邊界層內的層雲均會提前破裂,並發展為層積雲底下積雲型態:若-∆q_t不變(減少2.00 g kg-1),邊界層內層雲破裂提前約50分鐘(1小時40分鐘);形成層積雲底下積雲型態提前約1小時30分鐘(7小時20分鐘),均比有較大〖∆θ〗_l的環境快3.8倍,且邊界層頂的高度成長速率為較大〖∆θ〗_l環境的1.7倍。
我們發現,自由大氣與邊界層內的水氣含量差異及逆溫強度均對海洋性低雲在雲型轉換時期的雲層破裂速率、對流胞的生成速率有顯著影響,而邊界層頂的高度成長速率主要受逆溫強度影響。顯示海洋性低雲隨著氣流線往低緯度移行時,自由大氣狀態的重要性。
This study aims to discuss the cloud structure transition of marine low clouds propagating equatorward from the subtropics. Using the three dimensional Vector Vorticity equation cloud-resolving Model (VVM), idealized experiments are performed to determine the timing of stratus cloud to cumulus-under-stratus transition. In the control experiment, sea surface temperature (SST) increases as the large-scale subsidence decreases following the observational track calculated with the Lagrangian method. Sensitivity experiments are performed by modifying the total water mixing ratio difference (〖-∆q〗_t) and liquid water potential temperature difference (∆θ_l) between the free atmosphere and the boundary layer to evaluate the timing of stratus cloud breakup and cumulus-under-stratocumulus cloud development.
The timing of the transition is determined by the liquid water path (LWP) probability density function (PDF) analyses. The results suggest that the stratus clouds breakup occurs around 44 minutes in the control run, and transits to cumulus-under-stratocumulus around 3 hours 28 minutes. While 〖-∆q〗_t increases (decreases) by 2.00 g kg-1, the timing of the stratus clouds breakup advances (postpones) 35 minutes (1 hour 20 minutes), and the timing of the cumulus-under-stratocumulus development advances (postpones) 1 hour 50 minutes (6 hours 25 minutes).
In the experiments when the ∆θ_l decreases 4.98 K, the timing of stratus cloud breakup and cumulus-under-stratocumulus development both advances. While 〖-∆q〗_t stays the same (decreases by 2.00 g kg-1), the timing of the stratus clouds breaking advances 50 minutes (1 hour 40 minutes), and the timing of the cumulus-under-stratocumulus development advances 1 hour 30 minutes (7 hours 20 minutes). The timing of the cumulus-under-stratocumulus development is 3.8 times faster as well as the boundary layer height raises 1.7 times faster than the experiments which have higher ∆θ_l.
The above experiments suggest that the transition of the marine boundary clouds are influenced by both 〖-∆q〗_t and ∆θ_l. On the other hand, the development of boundary layer depth is mainly influenced by ∆θ_l.
目錄
摘 要 I
Abstract III
第一章 前言 1
第二章 模式設定與研究方法 7
2-1 模式簡介 7
2-2 模式設計 7
2-3 資料介紹 8
2-4 研究方法 9
2-4-1 實驗設計 9
2-4-2 不同雲型態的液態水路徑(Liquid Water Path,LWP)以及其雲水垂直分布 11
第三章 實驗結果 13
3-1 控制實驗(CTR) 13
3-2 邊界層頂之上環境影響 18
3-2-1 乾化自由大氣(SD)實驗及濕化自由大氣(SW)實驗 18
3-2-2 降低逆溫強度(UC)實驗及同時降低逆溫強度及濕化自由大氣(UW)實驗 22
第四章 結論 27
參考文獻 30
表 35
圖 37
附錄 甲 實驗設定比較 54
附錄 乙 名詞解釋 55
Arakawa, A., and C.-M. Wu, 2013: A unified representation of deep moist convection in numerical modeling of the atmosphere. Part I. J. Atmos. Sci., 70, 1977–1992
Boers, R., and R. M. Mitchell, 1994: Absorption feedback in stratocumulus clouds—Influence on cloud-top albedo. Tellus A, 46, 229-241.
Bretherton, C. S., and M. C. Wyant, 1997: Moisture transport, lower tropospheric stability and decoupling of cloud-topped boundary layers. J. Atmos. Sci., 54, 148-167.
Chung, D., G. Matheou, and J. Teixeira, 2012: Steady-state large-eddy simulations to study the stratocumulus to shallow cumulus cloud transition. J. Atmos. Sci., 69, 3264–3276.
Deardorff, J. W., 1972: Numerical investigation of neutral and unstable planetary boundary layers. J. Atmos. Sci., 29, 91-115.
——, 1980: Stratocumulus-capped mixed layers derived from a three-dimensional model. Bound. Layer Meteor. 18, 495-527.
Hahn, C. J., and S. G. Warren, 2007: A gridded climatology of clouds over land (1971–96) and ocean (1954–97) from surface observations worldwide. Carbon Dioxide Information Analysis Center Tech. Rep. NDP-026E, 71 pp.
Iacono, M. J., J. S. Delamere, E. J. Mlawer, M. W. Shephard, S. A. Clough, and W. D. Collins, 2008: Radiative forcing by long-lived greenhouse gases: Calculations with the AER radiative transfer models. J. Geophys. Res., 113, D13103.
Jung, J.-H. and A. Arakawa, 2008: A three-dimensional anelastic model based on the vorticity equation. Mon. Wea. Rev. 135, 276–294.
——. and ——, 2010: Development of a quasi-3d multiscale modeling framework: motivation, basic algorithm and preliminary results. J. Adv. Model. Earth Syst., 2, 31 pp.
Koren, I., and G. Feingold, 2013: Adaptive behavior of marine clouds. Sci. Rep., 3, 2507, doi:10.1038/srep02507.
Krueger, S.K., G.T. McLean, and Q. Fu, 1995: Numerical simulation of the stratus-to-cumulus transition in the subtropical marine boundary layer. Part I: Boundary-layer structure. J. Atmos. Sci., 52, 2839–2850.
Kuo, H.-C., and W. H. Schubert, 1988: Stability of cloud-topped boundary layers. Quart. J. Roy. Meteor. Soc., 114, 887-916.
Lilly, D. K., 1968: Models of cloud-topped mixed layers under a strong inversion. Q. J. R. Meteorol. Soc., 94, 292–308.
Neiburger, M., D. S. Johnson and C. W. Chien, 1961: Studies of the structure of the atmosphere over the Eastern Pacific Ocean in summer, I: The inversion over the Eastern North Pacific Ocean. Univ. Calif. Publ. Meteor., 1, No. 1.
Nicholls, S., 1984: The dynamics of stratocumulus: aircraft observations and comparisons with a mixed layer model. QJR Meteorul Soc. 110, 783-820.
——, and J. Leighton, 1986: An observational study of the structure of stratiform cloud sheets: Part I. Structure. Quart. J. Roy. Meteor. Soc., 112, 431–460.
Randall, D. A., 1980: Conditional Instability of the First Kind Upside-Down. J. Atmos. Sci., 37, 125-130.
——, and M. J. Suarez, 1984: On the Dynamics of Stratocumulus Formation and Dissipation. J. Atmos. Sci., 41, 3052-3057.
Sandu, I., B. Stevens and R. Pincus, 2010: On the transitions in marine boundary layer cloudiness. Atmos. Chem. Phys., 10, 2377-2391.
——, and ——, 2011: On the factors modulating the stratocumulus to cumulus transitions, J. Atmos. Sci., 68, 1865–1881.
Schubert, W. H., J. S. Wakefield, E. J. Steiner, and S. K. Cox, 1979: Marine stratocumulus convection, Part I: Governing equations and horizontally homogeneous solutions. J. Atmos. Sci., 36, 1286-1307.
——, ——, ——, and ——, 1979: Marine stratocumulus convection, Part II: Horizontally inhomogeneous solutions. J. Atmos. Sci., 36, 1308-1324.
——, P. E. Ciesielski, C. Lu and R. H. Johnson, 1995: Dynamical adjustment of the trade wind inversion layer. J. Atmos. Sci., 52, 2941-2952.
Shutts, G. J., and M. E. B. Gray, 1994: A numerical modeling study of the geostrophic adjustment process following deep convection. Quart. J. Roy. Meteor. Soc., 120, 1145–1178.
Simmons, A. and S. Uppala and D. Dee and S. Kobayashi, 2006/2007: ERA-INTERIM: New ECMWF reanalysis products from 1989 onwards, ECMWF Newsletter, 110, 25–35.
Stevens, B., 2000: Cloud transitions and decoupling in shear-free stratocumulus-topped boundary layers. Geophys. Res.Lett., 27, 2557-2560.
Turton, J. D. and S. Nicholls, 1987: A study of the diurnal variation of stratocumulus using a multiple mixed layer model. Quart. J. Roy. Meteor. Soc., 113, 969-1010.
Wang, S., 1993: Modeling marine boundary layer clouds with a two-layer model: A one-dimensional simulation. J. Atmos. Sci., 50, 4001-4021.
——, Albrecht, B. A., and Minnis P., 1993: A regional simulation of marine boundary-layer clouds. J. Atmos. Sci., 50, 4022–4043.
Wood, R., and C. S. Bretherton, 2004: Boundary layer depth, entrainment and decoupling in the cloud-capped subtropical and tropical marine boundary layer. J. Climate, 17, 3575-3587.
——, 2012: Review: Stratocumulus clouds. Mon. Wea. Rev., 140, 2373–2423.
Wyant, M. C., C. S. Bretherton, H. A. Rand, and D. E. Stevens, 1997: Numerical simulations and a conceptual model of the stratocumulus to trade cumulus transition. J. Atmos. Sci., 54, 168-192.
Wu, C.-M., and A. Arakawa (2011), Inclusion of surface topography into the vector vorticity equation model (VVM), J. Adv. Model. Earth Syst.,
3(2),
Wu, C.-M., and A. Arakawa, 2011: Inclusion of surface topography into the vector vorticity equation model (VVM), J. Adv. Model. Earth Syst.,3, M06002.
——,and——, 2014. A unified representation of deep moist convection in numerical modeling of the atmosphere. Part II. J. Atmos. Sci. 71, 2089–2103.
——, Lo, M.-H., Chen, W.-T., Lu, C.-T., 2015. The impacts of heterogeneous land surface fluxes on the diurnal cycle precipitation: A framework for improving the GCM representation of land-atmosphere interactions. J. Geophys. Res. 120, 3714–3727.
Xiao, H.; Wu, C. M.; Mechoso, C. R., 2011. Buoyancy reversal, decoupling and the transition from stratocumulus-topped to trade cumulus-topped marine boundary layers. Climate Dyn., 37, 971–984, doi:10.1007/s00382-010-0882-3.
——, W. I. Gustafson Jr., and H. Wang, 2014: Impact of subgrid-scale radiative heating variability on the stratocumulus-to-trade cumulus transition in climate models. J. Geophys. Res. Atmos., 119, 4192-4203
Yamaguchi, T., and D. A. Randall, 2008: Large-eddy simulation of evaporatively driven entrainment in cloud-topped mixed layers. J. Atmos. Sci., 65, 1481-1504.
Zhang, Y., B. Stevens, and M. Ghil, 2005: On the diurnal cycle and susceptibility to aerosol concentration in a stratocumulus-topped mixed layer. Quart. J. Roy. Meteor. Soc., 131, 1567–1583.
林佑宇,2015:重力波動對層積雲系統垂直結構及雲量之影響,國立台灣大學大氣科學研究所碩士論文,85頁。
蔡佳穎,2015:層積雲動力系統之分歧現象,國立台灣大學大氣科學研究所碩士論文,67頁。
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