用户名: 密码: 验证码:
海雾形成与发展机制的观测分析与数值模拟研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
本文利用尽可能多的观测资料和中尺度大气模式Regional Atmospheric Modeling System(RAMS)的高分辨率数值模拟结果,对1977年08月03日发生在荷兰北部Cabauw地区的陆地辐射雾、2004年04月11日黄海海雾和2005年03月08日东黄海海雾的形成、发展和演变过程进行了详尽的刻画,并对其形成与发展机制进行了研究。对Cabauw地区陆地辐射雾的模拟研究表明,RAMS模式对雾有较强的刻画能力。对两个海雾个例的观测与数值模拟研究发现,两者具有完全不同的特点,湍流、辐射、平流和海表温度(SST)等物理因素在其形成与发展过程中起不同的作用。
     在荷兰北部Cabauw地区陆地辐射雾的形成过程中,由于夜间长波辐射冷却使近地面空气温度降低,使其达到饱和凝结成雾,垂直风切变产生的湍流使雾向上发展。而随着太阳的升起,短波辐射对雾层的加热作用以及地面长波辐射的加强,使雾区低层温度迅速升高,造成雾区低层的层结不稳定,湍流增强,使雾向上发展。伴随着雾向上发展,云水混合比降低,减弱了辐射冷却作用,加速破坏逆温层结。在湍流的作用下,雾迅速向高空发展,并随气温升高逐渐消失。
     2004年04月11日海雾覆盖黄海大部分地区。观测分析表明在海雾发生前气温高于海温,RAMS数值模拟结果显示由于大气层结稳定,垂直风切变较弱,不能产生足够强的湍流使海面冷却降低低层大气的温度凝结成雾。垂直风切变增大,可加速大气的热量向海面传输,海雾在近海面处形成。由于雾本身的长波辐射冷却作用,使雾区降温到SST以下,引起海面的蒸发。而较弱的湍流不能使蒸发的水汽向上发展,水汽在辐射作用下产生凝结,使云水混合比在贴近海面处最大,且随高度迅速降低。这种云水混合比的垂直分布在辐射冷却的作用下进一步增加大气层结的稳定性,抑制湍流的发展,使海雾贴近在海面上。在发展阶段,海雾在湍流的作用下向上发展,近海面处的云水混合比减小,雾顶的强辐射冷却作用使雾顶处的云水含量较高,在短波辐射和雾顶向下发出的长波辐射作用下,雾低层加热。垂直风切变对湍流起产生作用,并随雾区向东北方向移动,在海雾水平发展过程中对湍流的发展起正贡献。SST敏感性试验表明,增加SST使气海温差减小,并增大雾区的范围,减小SST使气海温差增大,并减小雾区的范围。模式大气辐射敏感性试验表明,关闭液态水的长波辐射后山东半岛东南侧海区海雾消失,成山头东北部海雾仍然存在。模式微物理过程敏感性试验表明,改变单位质量的雾滴个数只会影响雾的浓度,而不会影响雾的形态和水平分布。模式水平分辨率敏感性试验表明,海雾的形成与发展对模式水平分辨率从8km到4km的改变并不敏感。
     与2004年04月11日的黄海海雾不同,2005年03月08-09日海雾首先在东海上空生成,并随天气系统的变化从南向北推进,逐步影响我国东海及黄海海区。此次海雾发生时垂直风切变较强,有足够强的湍流使海面冷却一定高度的大气,形成高度较高的雾层。大气长波辐射冷却作用在雾顶附近较强,形成了高的云水混合比含量区,而在近海面处大气辐射冷却作用较弱,云水混合比较低。在海雾的低层,大气层结稳定性较弱,垂直风切变能够产生足够的湍流,但在雾顶处稳定层结的抑制下,湍流迅速减弱,使雾顶维持在一定高度。在09日,由于南风和下沉运动将暖空气输送到东海上空,不但增加了近海面的大气温度,而且增加了大气的层结稳定性,抑制了湍流的发展,海面很难迅速冷却低空大气使之饱和,造成东海上空海雾消失。模式SST敏感性试验表明,增加SST减小气海温差会减小雾区范围,但雾顶发展较高,减小SST会加大气海温差,增加雾区的范围,雾顶高度会降低。模式辐射敏感性试验表明,液态水的长波辐射对该海雾的形成起不到决定性作用,但对其增强十分重要。
     通过比较2004年04月11日黄海海雾和2005年03月08日东黄海海雾的特点及形成机制发现,前者雾顶较低,云水含量最大区贴近海面,且气温低于海温,后者雾顶较高,云水含量最大区在雾顶部,气温高于海温。其产生原因是由于前者垂直风切变对湍流的产生作用弱于后者,而层结稳定性和辐射冷却作用均强于后者造成的。研究表明海雾的形成与发展机制十分复杂,需要更多的观测和数值模拟研究才能阐明。
In this thesis, the formation and development mechanisms of a land radiation fog oc-curred around Cabauw, Netherland on 3 August 1977, two sea fog cases formed over the Yel-low Sea on 11 April 2004 and the East China Sea on 08 March 2005, respectively, are inves-tigated by using almost all available observational data and Regional Atmospheric Modeling System (RAMS) high-resolution modeling results. The modeling of Cabauw land radiation fog shows that the RAMS model has the considerable ability to document the fog formation and development processes well. After examining two sea fog cases observationally and nu-merically, it is indicated that they are quite different cases. Advection, turbulence, radiation and Sea Surface Temperature (SST) played different roles in their formation and development processes.
     The Cabauw land fog formed near the land surface mainly due to the long-wave radia-tion cooling at night time, which led the air temperature decrease below to dew-point and the air was condensed into fog. The fog developed gradually because of the turbulence effect. The fog near ground was warmed up gradually by the radiation heating from both fog top and ground surface after the sunrise. Warming effect around fog base destroyed the temperature inversion layer and made the buoyancy favorable for the turbulence development, which makes the Turbulent Kinetic Energy (TKE) grow rapidly and the fog top rise consequently. With the cloud water reduction caused by fog top rising and short wave radiation enhancing, the radiation cooling around fog top dismissed gradually, and the temperature inversion layer near the fog top could not be maintained, which caused the fog to disappear after several hours.
     An extremely dense fog event over the Yellow Sea on 11 April 2004 is investigated ob-servationally and numerically. Observations showed that the almost all area of the Yellow Sea was occupied by fog on 11 April 2004, and the lower level air temperature was higher than SST prior to the sea fog formation. By examining RAMS modeling results, the fog formation mechanism can be drawn as follows. The turbulence near the sea surface was strong enough to enhance the heat exchange between the warmer moisture air and underlying colder sea sur-face, leading the sea fog formation at lower-level. Due to the long wave radiation cooling ef-fect, the fog enhanced and the air temperature fell down below the SST, which makes the evaporation occurs in the fog area. Long wave radiation cools down the fog layer to make it more stable and restrict the of turbulence development. The maximum cloud water center maintains at the fog bottom. Based on the modeling result, the thermal-dynamical budget analysis indicates that the long-wave radiation cooling plays the most important role in the maintaining temperature inversion layer during the development stage. The buoyancy makes against the development of TKE in the fog layer, and the vertical wind shear produces turbu-lence around the fog skirt area. A series of SST experiments indicated that increasing 1oC of SST may enlarge the fog area, and decreasing 1oC of SST may reduce the fog area, respec-tively. The fog over the southern Yellow Sea disappears when turns off the long wave radia-tion emitted by liquid water. The experiments of model micro-physics indicated that the hori-zontal distribution and the sea fog shape in the modeling did not have significant change with the change of cloud-droplet number in model. The experiments of model horizontal resolution showed that the fog formation and development processes were not sensitive to the minor change of horizontal resolution from 8 km to 4 km
     Different from the sea fog case on 11 April 2004, another sea fog occurred over the Yel-low and East China Seas on 08 March 2005. The fog formed over the East China Sea initially and moved over the Yellow Sea with the synoptic system movement. Based upon the RAMS modeling results, the detailed formation process of the fog can be described as follows. The sea fog occurred because the colder sea surface may cool the air above with much stronger turbulence. The long–wave radiation cooling made the sea fog more denser, and the cloud water center with high value formed near the fog top. In the fog area, the air temperature is higher than SST, because the maximum cloud water formed near fog top and the radiative cooling is not strong enough to cool the air in the fog bottom. The SST experiments indicated that increasing 1oC of SST may make the fog top higher, and decreasing 1oC of SST may make the fog top lower, respectively. The radiation experiments shows that the long wave ra-diation emitted by liquid water plays an important role in the sea fog enhancing.
     Turbulence, radiation, advection and SST are important factors for the sea fog formation and development. Different characteristics of these two fog cases are mainly due to the rela-tive contributions of these factors. Comparing the two sea fog events, it is found that in the former sea fog case, the TKE is much weaker, the fog top was lower, the area contains higher cloud water was locates near the sea surface, and the air temperature was lower than SST. In the later sea fog case, the TKE is much stronger, the fog top was much higher, the area of higher cloud water was near the fog top, and the air temperature was higher than SST. It is concluded that the formation and development mechanisms of sea fog are so complicated, and much deeper understanding of more fog cases is necessary.
引文
鲍献文,王鑫,孙立潭,周发琇,2005:卫星遥感全天候监测海雾技术与应用,高技术通讯,15,101-106。
    樊琦,王安宇,范绍佳,吴兑,梁嘉静,2004:珠江三角洲地区一次辐射雾的数值模拟研究,气象科学,24,1-8。
    傅刚,张涛,周发琇,2002:一次黄海海雾的三维数值模拟研究,青岛海洋大学学报, 2, 859-876。
    傅刚,王菁茜,张美根,郭敬天,郭明克,郭可彩,2004:一次黄海海雾事件的观测与数值模拟研究-以2004年4月11日为例,中国海洋大学学报,34, 720-726。
    李子华,张利民,楼小凤,1993:重庆市区冬季雾的宏微观结构及其物理成因,南京气象学院学报,16, 48-54。
    胡瑞金,董克慧,周发琇,2006:海雾生成过程中平流、湍流和辐射效应的数值试验,海洋科学进展,24,256-165。
    黄玉生,黄玉仁,李子华,陈宝君,黄建平,顾江新,2000:西双版纳冬季雾的微观物理结构及其演变过程,气象学报,58,715-725。
    彭虎,李子华,1992:包含详细微物理过程的一维辐射雾模式,重庆环境科学,14,49-54。王彬华,1983:海雾,海洋出版社。
    王鑫,黄菲,周发琇,2006:海沿海夏季海雾形成的气候特征,海洋学报,28,26-34。
    周发琇,王鑫,鲍献文,2004:黄海春季海雾形成的气候特征,海洋学报,26,28-37。
    徐静琦,张正,魏皓,1994:青岛海雾雾滴谱与含水量观测与分析,海洋湖沼通报,2,174-178。
    尹球,许绍祖,1993:辐射雾生消的数值研究(I)—数值模式,气象学报,51,351-359。
    尹球,许绍祖,1994:辐射雾生消的数值研究(Ⅱ)—生消机制,气象学报,52,60-67。
    张利民,李子华,1993:重庆雾的二维非定常数值模拟,大气科学,17,750-755。
    Anderson, J.B., 1931: Observations from airplanes of cloud and fog conditions along the Southern California coast, Mon. Wea. Rev., 59, 264–270.
    Ballard, S.P., B.W. Golding, and R.N.B. Smith, 1991: Mesoscale model experimental fore-casts of the haar of northeast Scotland. Mon. Wea. Rev., 119, 2107–2123.
    Bendix, J., 1995: A case study on the determination of fog optical depth and liquid water path using AVHRR data and relations to fog liquid water content and horizontal visibility. Int. J. Remote Sensing, 16, 515-530.
    Bendix, J., B. Thies, J. Cermak, and T. Nau?, 2005:Ground fog detection from space based on MODIS. daytime data–a feasibility study. Wea. and Fore., 20, 989-1005.
    Bergot, T., and D.Guedalia, 1994: Numerical forecasting of radiation fog. Part I: Numerical model and sensitivity tests, Mon. Wea. Rev. 122, 1218–1230.
    Bergot, T., 2007: Quality assessment of the Cobel-Isba numerical forecast sytem of fog and low clouds. Pure Appl. Geophys. 164, 1265-1282.
    Brown, R., and W.T. Roach, 1976: The physics of radiation fog: II - A numerical study, Quart. J. Roy. Meteor. Soc. 102, 335–354.
    Cermak, J., and J. Bendix, 2007: Dynamical nighttime fog/low stratus detection based on Meteosat SEVIRI data - A feasibility study. Pure Appl. Geophys. 164, 1179-1192.
    Chen, C., and W.R. Cotton, 1983: A one-dimensional simulation of the stratocumulus-capped mixed layer. Bound-Layer Meteor, 25, 289-321.
    Douglas, C., 1930: Cold fogs over the sea. Meteor. Mag., 65, 133–135.
    Emmons, G., and R. Montgomery, 1947: Note on the physics of fog formation. J. Meteor., 4, 206.
    Ernst, J.A., 1975: Fog and stratus“invisible”in meteorological satellite infrared (IR) imagery. Mon. Wea. Rev., 103, 1024–1026.
    Eyre, J.R., L. Brownscombe, and R. J. Allam, 1984: Detection of fog at night using Advanced Very High Resolution Radiometer (AVHRR) imagery. Meteor. Mag., 113, 266-271.
    Findlater, J., 1985: Field investigations of radiation fog formation at outstations, Meteor. Mag. 114, 187-201.
    Fisher, E.L., and P. Caplan, 1963: An experiment in numerical prediction of fog and stratus, J. Atmos. Sci., 20, 425–437.
    Fitzjarrald, D.R., and G.G. Lala, 1989: Hudson valley fog environments, J. Appl. Meteor. 28, 1303-1328.
    Fu, G., J. Guo, S-P. Xie, Y. Duan, and M. Zhang, 2006: Analysis and high-resolution modeling of a dense sea fog event over the Yellow Sea, Atmos. Res., 81, 293-303.
    Fu, G., J. Guo, P. Angeline, and P. Li, 2008: An Analysis and modeling study of a sea fog event over the Yellow and Bohai Sea, J. Ocean univ. Chin., 7, 27-34.
    Gao, S., H. Lin, B. Shen, and G. Fu, 2007: A heavy sea fog event over the Yellow Sea in March 2005: Analysis and numerical modeling. Adv. Atmos. Sci., 24, 65-81.
    Gao, S., W. Wu, and L. Zhu, 2007: Detection of nighttime sea fog/stratus over the Yellow Sea using MTSAT-1R IR data.(Submitted to J. Ocean univ. Chin.)
    Gazzi, M., V. Vincentini, and C. Pesci, 1997:Dependence of a black target’s apparent lumi-nance on fog droplet size distribution, Atmos. Environ., 31, 3441–3447.
    Gazzi, M., T. Georgiadis, and V. Vincentini, 2001:Distant contrast measurements through fog and thick haze, Atmos. Environ.,35, 5143–5149.
    Gultepe, I., Isaac, G., Macpherson, I., Marcotte, D., and Strawbridge, K., 2003: Characteristics of moisture and heat fluxes over leads and polynyas, and their effect on Arctic clouds during FIRE.ACE, Atmos. and Ocean, 41, 15–34.
    Gultepe, I.,R. Tardif, S.C. Michaelides, J. Cermak, A. Bott, J. Bendix, M.D. Muller, M. Pagowski, B. Hansen, G. Ellrod, W. Jacobs, G. Toth, and S.G. Cober,2007:Fog re-search: a review of past achievements and future perspectives, Pure Appl. Geophys., 164,1121–1159.
    Gultepe, I., and J. Milbrandt, 2007: Microphysical observations and mesoscale model simula-tion of a warm fog case during FRAM project, Pure Appl. Geophys. 164, 1161-1178.
    Gurka, J.J., and V. J. Oliver, 1974: Fog persistence under a cirrus band. Mon. Wea. Rev., 102, 869–870.
    Gurka, J. J., 1978: The role of inward mixing in the dissipation of fog and stratus. Mon. Wea. Rev., 106, 1633–1635.
    Harrington, J.Y., 1997: The effects of radiative and micro-physical processes on simulated warm and transition season Arctic stratus. PhD Diss., Atmospheric Science Paper No.637, Colorado State University, Department of Atmospheric Science, FortCollins, CO80523, 289pp.
    Heidinger, A.K., and G.L.Stephens, 2000: Molecular line absorption in a scattering atmos-phere. Part II: Application to remote sensingin the 02 A band.J. Atmos. Sci., 57, 1615-1634.
    Holets, S., And R.N. Swanson, 1981: High-inversion fog episodes in Central California, J. Appl. Meteor. 20, 890–899.
    Koracin, D., J. Lewis, W. Thompson, C. Dorman, and J. Businger, 2001: Transition of stratus into fog along the California Coast: Observations and modeling. J. Atmos. Sci., 58, 1714–1731.
    Kunkel, B. A., 1984: Parameterization of droplet terminal velocity and extinction coefficient in fog models. J. Climate Appl. Meteor., 23, 34–41.
    Kuroiwa, D., 1956: The composition of sea-fog nuclei as identified by electron microscope. J. Atmos. Sci., 13, 408-410.
    Lamb, H., 1943: Haars or North Sea fogs on the coasts of Great Britain. Meteorology Office Publication M. O., 504, 24.
    Leipper, D. F., 1948: Fog development at San Diego, California. J. Mar. Res., 7, 337-346.
    Lewis, J. M., D. Kora in, and K. T. Redmond, 2004: Sea fog research in the United Kingdom and United States: a historical essay including outlook. Bull. Amer. Meteor. Soc., 85, 395–408.
    Minnis, P., P.W. Heck, D.F. Young, C.W. Fairall, and J.B. Snider, 1992: Stratocumulus cloud properties from simultaneous satellite and island-based instrumentation during FIRE. J. Appl. Meteor., 31, 317-339.
    Musson-Genon, L., 1987: Numerical simulation of a fog event with a one-dimensional boundary layer model. Mon. Wea. Rev. 115, 592-607.
    Nakanishi, M., 2000: Large-eddy simulation of radiation fog. Boundary-Layer Meteor., 94, 461-493.
    Oliver, D., W. Lewellen, and G. Williamson, 1978: The interaction between turbulent and ra-diative transport in the development of fog and low-level stratus. J. Atmos. Sci., 35, 301–316.
    Pagowski, M., I. Gultepe, and P. King, 2004: Analysis and modeling of an extremely dense fog event in Southern Ontario. J. Appl. Meteor., 43, 3–16.
    Roach, W. T., R. Brown, S.J. Caughey, J. Garland, J. A. Garland, and C. J. Readings, 1976: The physics of radiation fog: Part I: A field study, Quart. J. R. Met. Soc., 102, 313-333.
    Roach, W.T., 1995a: Back to basics: Fog: Part 2– The formation and dissipation of land fog,Weather, 50, 7–11.
    Roach, W.T., 1995b: Back to basics: Fog: Part 3– The formation and dissipation of sea fog, Weather, 50, 80–84.
    Rutledge, S.A., and P. V. Hobbs, 1983: The mesoscale and microscale structure and organiza-tion 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.
    Ryznar, E., 1977: Advection-radiation fog near Lake Michigan, Atmos. Environ. 11, 427–43.
    Saunders, P.M., 1964: Sea smoke and steam fog, Quart. J. Roy. Meteor. Soc., 90, 156–165.
    Stallabrass, J.R., 1985: Measurements of the concentration of falling snow. Preprints, Snow Property Measurements Workshop, Lake Louise, AB, Canada, National Research Coun-cil of Canada, 389–410.
    Stoelinga, M. T., and T.T. Warner, 1999: Nonhydrostatic, mesobeta-scale model simulations of cloud ceiling and visibility foran east coast winter precipitation event. J. Appl. Meteorol, 38, 385– 404.
    Taylor, G., 1917: The formation of fog and mist. Quart. J. Roy. Meteor. Soc., 43, 241–268.
    Taylor, G., 1915: Eddy motion in the atmosphere. Philos. Trans. Roy. Soc. London Ser. A, 215, 1–26.
    Thompson, W.T. and S.D. Burk, 2003: Investigation of fog and low clouds associated with a coastally trapped disturbance. 5th Coastal Atmospheric Ocean Prediction Processes Conf., Seattle, WA, 8-12 Aug 2003, AMS, 70-75.
    Trémant, M., 1987:La Prévision du brouilliard en mer, Meteorologie Maritime et Activies. Oceanograpiques Connexes Raport, WMO, 20. 127 pp.
    Turner, J., R. J. Allam, and D. R. Maine, 1986: A case study of the detection of fog at night using channels 3 and 4 on the advanced very high resolution radiometer (AVHRR). Me-teor. Mag., 115, 285-290.
    Turton, J.D., and R. Brown, 1987: A comparison of a numerical model of radiation fog with detailed observations, Quart. J. Roy. Meteor. Soc. 113, 37–54.
    Underwood, S.J., G.P. Ellrod, and A.L. Kuhnert, 2004:A multiple-case analysis of nocturnal radiation-fog development in the central valley of California utilizing the GOES night-time fog product, J. Appl. Meteor., 43, 297–311.
    Walko, R.L., C.J. Tremback, R.A. Pielke., and W.R. Cotton, 1995: An interactive nesting al-gorithm for stretched grids and variable nesting ratios. J. Appl.Meteor., 34, 994-999.
    Wells, W. C., 1814: Essay on dew, and several appearances connected with It. Taylor and Hessey, 146 pp.
    Woodcock, A. H., 1978: Marine fog droplets and salt nuclei - Part 1. J. Atmos. Sci. 35, 657-664.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700