地形强迫对大气长波调整的可能影响
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摘要
地形作为大气的外部强迫,其动力和热力作用对波动结构演变及极端天气出现都有不能忽视的作用。本文通过数值求解考虑地形强迫的β平面正压准地转位势涡度方程,探讨了地形强迫作用对大气长波调整的可能影响,结果表明:同非线性作用和纬向非均匀基流作用一样,无基流情形下具有纬向差异的地形分布影响了大气长波结构的演变,也能强迫出大气长波调整现象。大气长波调整依赖于地形的高度和地形分布,地形越高,长波越容易出现波数的调整;地形波数越大,即地形结构复杂,越不易出现波数变化。大气长波调整还与纬度有关,纬度越高,β越小,地形强迫作用越突出,长波调整容易出现;反之,低纬度以β效应为主的线性波动不易出现波数调整。大气长波调整对波动初始波动的振幅不敏感,但依赖于波动的初始结构。此外,有基流作用时,地形强迫还是诱发定常波的重要因素,且定常波流场结构依赖于地形高度分布,与波动初始结构无关。
Topography is an important external forcing factor on the atmosphere and has orographic thermal and dynamic impacts on the evolution of atmospheric long waves and the emergence of extreme weather.In this study,numerical calculation with the forced β plane quasi-geostrophic potential vorticity equation considering linear Rossby waves with and without the influence of basic flow is used to investigate the possible impacts of topography on the adjustment of long waves.The results show that without the basic flow,the phenomenon of long-wave adjustment was accompanied by the forcing of zonal nonuniform topography,which is also an important mechanism for the adjustment.The adjustment is closely related to topographic amplitude and zonal structure.As the amplitude of topography increases,the phenomenon of wave-number adjustment in the evolution of linear Rossby waves becomes more obvious.However,the adjustment is difficult to identify in topography with a high zonal wave number.Long-wave adjustment is also associated with latitude.High latitude relates to a low β value in which the influence of topography is strong and adjustment of the wave number is simple.On the contrary,the wave number of a linear Rossby wave with a large β effect in low latitudes is not easily changed.Long-wave adjustment is associated with the structure of the initial field and is not sensitive to the amplitude of the initial fluctuation.Moreover,when the basic flow is considered,the forcing of topography is also an important factor in producing a solitary Rossby wave.The structure of this solitary wave is determined by the distribution of the topography and is independent of the structure of initial fluctuation.
Topography is an important external forcing factor on the atmosphere and has orographic thermal and dynamic impacts on the evolution of atmospheric long waves and the emergence of extreme weather.In this study,numerical calculation with the forced β plane quasi-geostrophic potential vorticity equation considering linear Rossby waves with and without the influence of basic flow is used to investigate the possible impacts of topography on the adjustment of long waves.The results show that without the basic flow,the phenomenon of long-wave adjustment was accompanied by the forcing of zonal nonuniform topography,which is also an important mechanism for the adjustment.The adjustment is closely related to topographic amplitude and zonal structure.As the amplitude of topography increases,the phenomenon of wave-number adjustment in the evolution of linear Rossby waves becomes more obvious.However,the adjustment is difficult to identify in topography with a high zonal wave number.Long-wave adjustment is also associated with latitude.High latitude relates to a low β value in which the influence of topography is strong and adjustment of the wave number is simple.On the contrary,the wave number of a linear Rossby wave with a large β effect in low latitudes is not easily changed.Long-wave adjustment is associated with the structure of the initial field and is not sensitive to the amplitude of the initial fluctuation.Moreover,when the basic flow is considered,the forcing of topography is also an important factor in producing a solitary Rossby wave.The structure of this solitary wave is determined by the distribution of the topography and is independent of the structure of initial fluctuation.
引文
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刁一娜,李建平,罗德海.2004.阻塞流场与瞬变涡动相互作用的动力学研究[J].大气科学,28:901–924.Diao Yina,Li Jianping,LuoDehai.2004.A dynamic study of the interaction between transient eddiesand blocking[J].Chin.J.Atmos.Sci.(in Chinese),28:901–924.
段安民,吴国雄,刘屹岷.2006.定常条件下感热和地形影响的Rossby波[J].气象学报,64:129–136.Duan Anmin,Wu Guoxiong,LiuYimin.2006.Steady wave-like solution of the Rossby wave with sensibleheating and topographic effects[J].Acta Meteor.Sin.(in Chinese),64:129–136.
Eliassen A,Palm E.1961.On the transfer of energy in stationary mountainwaves[J].Geofysiske Publikasjoner,22:1–3.
Held I M,Ting M F,Wang H L.2002.Northern winter stationary waves:Theory and modeling[J].J.Climate,15:2125–2144.
Huang R H,Gambo K.1981.The response of a model atmosphere in middlelatitude to forcing by topography and stationary heat sources[J].J.Meter.Soc.Japan,59:220–237.
黎爱兵,张立凤,张亮,等.2012.纬向非均匀基流对大气长波调整的作用[J].地球物理学报,55:1104–1113.Li Aibing,Zhang Lifeng,Zhang Liang,et al.2012.The effects of zonal non-uniform basic flow onadjustment of atmospheric long wave[J].Chinese J.Geophys.(inChinese),55:1104–1113.
Lorenz E N.1972.Barotropic instability of Rossby wave motion[J].J.Atmos.Sci.,29:258–26.
Lu C G,Byod J P.2008.Rossby wave ray tracing in a barotropic divergentatmosphere[J].J.Atmos.Sci.,65:1679–1691.
Luo D H,Li J P.2001.Interaction between a slowly moving planetary-scaledipole envelope Rossby soliton solition and a wavenumber-twotopography in a forced higher order nonlinear higher order nonlinearSchrodinger equation[J].Adv.Atmos.Sci.,18:239–256.
Schoeberl M R,Lindzen R S.1984.A numerical simulation ofbarotropic instability.Part I:Schrodinger equation[J].J.Atmos.Sci.,18:239–256.
盛华,陶诗言.1988a.青藏高原和落基山对气旋的动力影响[J].气象学报,46:130–141.Sheng Hua,Tao Shiyan.1988a.Dynamic effect ofQinghai–Xizang Plateau and Rocky Mountains on the lee cyclones[J].Acta Meteor.Sin.(in Chinese),46:130–141.
盛华,陶诗言.1988b.青藏高原与落基山背风气旋的对比分析(二)——诊断分析[J].大气科学,12:337–345.Sheng Hua,Tao Shiyan.1988b.A comparison between lee cyclones of Rocky Mountains andQinghai–Xizang Plateau—Part II:Diagnose[J].Chinese J.Atmos.Sci.(in Chinese),12:337–345.
谭本馗,伍荣生.1995.强迫耗散作用下的Rossby包络孤立波及其相互作用[J].大气科学,19:289–300.Tan Benkui,Wu Rongsheng.1995.Envelope solitary Rossby waves and their interactions under the influenceof forcing and dissipation[J].Chinese J.Atmos.Sci.(in Chinese),19:289–300.
陶诗言,卫捷.2008.2008年1月我国南方严重冰雪灾害过程分析[J].气候与环境研究,13:337–350.Tao Shiyan,Wei Jie.2008.Severesnow and freezing-rain in January 2008 in the southern China[J].Climatic and Environmental Research(in Chinese),13:337–350.
陶诗言.1980.中国之暴雨[M].北京:科学出版社,225pp.Tao ShiyanY.1980.Torrential Rain in China(in Chinese)[M].Beijing:SciencePress,225pp.
汪萍,戴新刚.2005.外强迫作用下正压大气非线性特征数值模拟[J].物理学报,54:4961–4870.Wang Ping,Dai Xingang.2005.Numericalmodeling of non-linear characteristics for barotropic atmosphere withexternal forcing[J].Acta Phys.Sin.(in Chinese),54:4961–4870.
Zeng Q C.1983.The evolution of a Rossby-wave packet in a threedimensional baroclinic atmosphere[J].J.Atmos.Sci.,40:73–84.
曾庆存,卢佩生.1980.非均匀基流上扰动的演变[J].中国科学A辑,23:1193–1202.Zeng Qingcun,Lu Peisheng.1980.The evolutionprocess of disturbances on non-uniform basic flow[J].Science in China,Ser.A(in Chinese),23:1193–1202.
张亮,张立凤,吴海燕,等.2010.正压Rossby波扰动能量[J].物理学报,59:44–53.Zhang Liang,Zhang Lifeng,Wu Haiyan,et al.2010.The disturbance energy of Rossby wave in barotropic atmosphere[J].Acta Phys.Sin.(in Chinese),59:44–53.
张顺利,陶诗言.2002.青藏高原对1998年长江流域天气异常的影响[J].气象学报,60:442–452.Zhang Shunli,Tao Shiyan.2002.Theinfluences of Tibetan Plateau on weather anomalies over ChangjiangRiver in 1998[J].Acta Meteor.Sin.(in Chinese),60:442–452.
张立凤,张亮,李崇银.2011a.真实基流中非线性Rossby波演变特征(一):数值模式设计[J].地球物理学报,54:629–633.Zhang Lifeng,Zhang Liang,Li Chongyin.2011a.The evolution characteristic ofnonlinear Rossby wave in the real basic flow.I:Numerical model design[J].Chinese J.Geophys.(in Chinese),54:629–633.
张立凤,张亮,李崇银.2011b.真实基流中非线性Rossby波演变特征(二):能量、结构演变及初始场的影响[J].地球物理学报,54:886–895.Zhang Lifeng,Zhang Liang,Li Chongyin.2011b.The evolution characteristic of nonlinear Rossby wave in the real basic flow.II:The energy and structure evolution of Rossby wave andeffect of the initial field on it[J].Chinese J.Geophys.(in Chinese),54:886–895.
张立凤,黎爱兵,高建华.2012.影响大气长波调整的因子分析[J].解放军理工大学学报(自然科学版),13:460–465.Zhang Lifeng,LiAibing,Gao Jianhua.2012.Analysis on impacting factors of atmosphericlong wave[J].Journal of PLA University Science and TechnologyNatural Science Edition(in Chinese),13:460–465.
赵强,于鑫.2008.完整Coriolis力作用下非线性Rossby波的精确解[J].地球物理学报,51:1304–1308.Zhao Qiang,Yu Xin.2008.Exact solutions to the nonlinear Rossby waves with a complete representationof the Coriolis force[J].Chinese J.Geophys.(in Chinese),51:1304–1308.
赵强,刘式达,刘式适.2000.切变基本纬向流中非线性赤道Rossby长波[J].地球物理学报,43:746–753.Zhao Qiang,Liu Shida,LiuShikuo.2000.Nonlinear equatorial Rossby long waves in a shear flow[J].Chinese J.Geophys.(in Chinese),43:746–753.
Zhao Q,Zhao Y,Liu S K.2006.Two-dimensional Rossby waves:Exactsolutions to Petviashvili equation[J].Commun.Theor.Phys.,45:414–416.
刁一娜,李建平,罗德海.2004.阻塞流场与瞬变涡动相互作用的动力学研究[J].大气科学,28:901–924.Diao Yina,Li Jianping,LuoDehai.2004.A dynamic study of the interaction between transient eddiesand blocking[J].Chin.J.Atmos.Sci.(in Chinese),28:901–924.
段安民,吴国雄,刘屹岷.2006.定常条件下感热和地形影响的Rossby波[J].气象学报,64:129–136.Duan Anmin,Wu Guoxiong,LiuYimin.2006.Steady wave-like solution of the Rossby wave with sensibleheating and topographic effects[J].Acta Meteor.Sin.(in Chinese),64:129–136.
Eliassen A,Palm E.1961.On the transfer of energy in stationary mountainwaves[J].Geofysiske Publikasjoner,22:1–3.
Held I M,Ting M F,Wang H L.2002.Northern winter stationary waves:Theory and modeling[J].J.Climate,15:2125–2144.
Huang R H,Gambo K.1981.The response of a model atmosphere in middlelatitude to forcing by topography and stationary heat sources[J].J.Meter.Soc.Japan,59:220–237.
黎爱兵,张立凤,张亮,等.2012.纬向非均匀基流对大气长波调整的作用[J].地球物理学报,55:1104–1113.Li Aibing,Zhang Lifeng,Zhang Liang,et al.2012.The effects of zonal non-uniform basic flow onadjustment of atmospheric long wave[J].Chinese J.Geophys.(inChinese),55:1104–1113.
Lorenz E N.1972.Barotropic instability of Rossby wave motion[J].J.Atmos.Sci.,29:258–26.
Lu C G,Byod J P.2008.Rossby wave ray tracing in a barotropic divergentatmosphere[J].J.Atmos.Sci.,65:1679–1691.
Luo D H,Li J P.2001.Interaction between a slowly moving planetary-scaledipole envelope Rossby soliton solition and a wavenumber-twotopography in a forced higher order nonlinear higher order nonlinearSchrodinger equation[J].Adv.Atmos.Sci.,18:239–256.
Schoeberl M R,Lindzen R S.1984.A numerical simulation ofbarotropic instability.Part I:Schrodinger equation[J].J.Atmos.Sci.,18:239–256.
盛华,陶诗言.1988a.青藏高原和落基山对气旋的动力影响[J].气象学报,46:130–141.Sheng Hua,Tao Shiyan.1988a.Dynamic effect ofQinghai–Xizang Plateau and Rocky Mountains on the lee cyclones[J].Acta Meteor.Sin.(in Chinese),46:130–141.
盛华,陶诗言.1988b.青藏高原与落基山背风气旋的对比分析(二)——诊断分析[J].大气科学,12:337–345.Sheng Hua,Tao Shiyan.1988b.A comparison between lee cyclones of Rocky Mountains andQinghai–Xizang Plateau—Part II:Diagnose[J].Chinese J.Atmos.Sci.(in Chinese),12:337–345.
谭本馗,伍荣生.1995.强迫耗散作用下的Rossby包络孤立波及其相互作用[J].大气科学,19:289–300.Tan Benkui,Wu Rongsheng.1995.Envelope solitary Rossby waves and their interactions under the influenceof forcing and dissipation[J].Chinese J.Atmos.Sci.(in Chinese),19:289–300.
陶诗言,卫捷.2008.2008年1月我国南方严重冰雪灾害过程分析[J].气候与环境研究,13:337–350.Tao Shiyan,Wei Jie.2008.Severesnow and freezing-rain in January 2008 in the southern China[J].Climatic and Environmental Research(in Chinese),13:337–350.
陶诗言.1980.中国之暴雨[M].北京:科学出版社,225pp.Tao ShiyanY.1980.Torrential Rain in China(in Chinese)[M].Beijing:SciencePress,225pp.
汪萍,戴新刚.2005.外强迫作用下正压大气非线性特征数值模拟[J].物理学报,54:4961–4870.Wang Ping,Dai Xingang.2005.Numericalmodeling of non-linear characteristics for barotropic atmosphere withexternal forcing[J].Acta Phys.Sin.(in Chinese),54:4961–4870.
Zeng Q C.1983.The evolution of a Rossby-wave packet in a threedimensional baroclinic atmosphere[J].J.Atmos.Sci.,40:73–84.
曾庆存,卢佩生.1980.非均匀基流上扰动的演变[J].中国科学A辑,23:1193–1202.Zeng Qingcun,Lu Peisheng.1980.The evolutionprocess of disturbances on non-uniform basic flow[J].Science in China,Ser.A(in Chinese),23:1193–1202.
张亮,张立凤,吴海燕,等.2010.正压Rossby波扰动能量[J].物理学报,59:44–53.Zhang Liang,Zhang Lifeng,Wu Haiyan,et al.2010.The disturbance energy of Rossby wave in barotropic atmosphere[J].Acta Phys.Sin.(in Chinese),59:44–53.
张顺利,陶诗言.2002.青藏高原对1998年长江流域天气异常的影响[J].气象学报,60:442–452.Zhang Shunli,Tao Shiyan.2002.Theinfluences of Tibetan Plateau on weather anomalies over ChangjiangRiver in 1998[J].Acta Meteor.Sin.(in Chinese),60:442–452.
张立凤,张亮,李崇银.2011a.真实基流中非线性Rossby波演变特征(一):数值模式设计[J].地球物理学报,54:629–633.Zhang Lifeng,Zhang Liang,Li Chongyin.2011a.The evolution characteristic ofnonlinear Rossby wave in the real basic flow.I:Numerical model design[J].Chinese J.Geophys.(in Chinese),54:629–633.
张立凤,张亮,李崇银.2011b.真实基流中非线性Rossby波演变特征(二):能量、结构演变及初始场的影响[J].地球物理学报,54:886–895.Zhang Lifeng,Zhang Liang,Li Chongyin.2011b.The evolution characteristic of nonlinear Rossby wave in the real basic flow.II:The energy and structure evolution of Rossby wave andeffect of the initial field on it[J].Chinese J.Geophys.(in Chinese),54:886–895.
张立凤,黎爱兵,高建华.2012.影响大气长波调整的因子分析[J].解放军理工大学学报(自然科学版),13:460–465.Zhang Lifeng,LiAibing,Gao Jianhua.2012.Analysis on impacting factors of atmosphericlong wave[J].Journal of PLA University Science and TechnologyNatural Science Edition(in Chinese),13:460–465.
赵强,于鑫.2008.完整Coriolis力作用下非线性Rossby波的精确解[J].地球物理学报,51:1304–1308.Zhao Qiang,Yu Xin.2008.Exact solutions to the nonlinear Rossby waves with a complete representationof the Coriolis force[J].Chinese J.Geophys.(in Chinese),51:1304–1308.
赵强,刘式达,刘式适.2000.切变基本纬向流中非线性赤道Rossby长波[J].地球物理学报,43:746–753.Zhao Qiang,Liu Shida,LiuShikuo.2000.Nonlinear equatorial Rossby long waves in a shear flow[J].Chinese J.Geophys.(in Chinese),43:746–753.
Zhao Q,Zhao Y,Liu S K.2006.Two-dimensional Rossby waves:Exactsolutions to Petviashvili equation[J].Commun.Theor.Phys.,45:414–416.