北极地区低平流层惯性重力波的观测研究
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摘要
南极地区重力波活动有大量报道,相对而言,北极地区重力波的研究还很少.本文利用极区Ny-Alesund站点(78.9°N,11.9°E)无线电探空仪从2012年4月1日到2017年3月31日共5年的观测数据,统计分析了北极地区低平流层惯性重力波的特征.观测显示,月平均纬向风在20km以下盛行东向风,再随着高度增加,逐渐呈现出半年振荡现象.对流层顶高度在5～13km范围内变化,其月平均高度显示出年循环,最高出现在夏季,约为10km,最低出现在冬季,约为8.5km.对流层和低平流层月平均温度都显示出明显的年周期变化,这与中低纬度观测结果有所不同.结合Lomb-Scargle谱分析和矢端曲线方法,估算了准单色惯性重力波参数.个例研究表明,低平流层惯性重力波呈现出远离源区的自由传播性质.统计结果显示,惯性重力波的水平和垂直波长分别集中在50～450km和1～4km范围内,本征频率集中在1～2.5倍惯性频率间,这些值都比中低纬度观测值稍小.垂直方向本征相速度主要集中在-0.3～0m·s~(-1),而纬向和经向本征相速度集中在-40～40m·s~(-1)之间.在5年的观测中,大约91.5%的惯性重力波向上传播.在冬季和早春,由于极地平流层极涡活动,激发出向下传播的惯性重力波,因此,向下传播的比例上升到相应月份的20%左右.由于低层大气盛行的东向风的滤波效应,低平流层大部分惯性重力波向西传播.波能量呈现出明显的年周期变化,最大值在冬季、最小值在夏季,与北半球中低纬度观测结果一致,表明北半球重力波活动普遍冬季强、夏季弱.
Relative to many investigations of inertial gravity waves(IGWs)in the Antarctic,IGW activity in the Arctic region is less reported.We use radiosonde observations at the Ny-Alesund station(78.9°N,11.9°E)during 5 years from 1 April 2012 to 31 March 2017 to study the IGW characteristics in the lower stratosphere over the Arctic.The observation reveals aprevailing eastward zonal background wind below 20 km,and then,with the increase of height,the monthly averaged zonal wind exhibits a semiannual oscillation.The tropopause is in a height range of 5～13 km,and its monthly averaged height shows an annual cycle with the maximum at about 10 km in summer and the minimum at about 8.5 km in winter.An obvious annual cycle can be seen in the background temperature from the troposphere to the lower stratosphere,which is different from the results at middle and low latitudes.By combining Lomb-Scargle spectrum and hodograph technique,the parameters of IGWs are estimated.The case analysis demonstrates that the lower stratospheric IGWs exhibit a feature of freely propagating waves.The statistical study indicates that the IGWs have the dominant horizontal and vertical wavelengths of 50～450 km and1～4 km,respectively,and the dominant intrinsic frequency being 1～2.5 times the inertia frequency.These values are slightly smaller than those observed at middle and low latitudes.The intrinsic phase speed is mainly in the range of-0.3～0 m·s~(-1) in the vertical direction,and in the range of-40～40 m·s~(-1) in both the zonal and meridional directions.About 91.5%of the IGWs propagate upward,while in winter and early spring,the downward propagating waves increase to about20% due to the activity of polar stratospheric vortex.Because of the filtering of the prevailing eastward zonal wind in the lower atmosphere,the IGWs in the lower stratosphere display a dominant direction of westward propagation.Wave energy is the maximum in winter and the minimum in summer,which is consistent with the results at middle and low latitudes in the northern hemisphere.This indicates that the IGW activity over the northern hemisphere is generally the strongest in winter and the weakest in summer.
Relative to many investigations of inertial gravity waves(IGWs)in the Antarctic,IGW activity in the Arctic region is less reported.We use radiosonde observations at the Ny-Alesund station(78.9°N,11.9°E)during 5 years from 1 April 2012 to 31 March 2017 to study the IGW characteristics in the lower stratosphere over the Arctic.The observation reveals aprevailing eastward zonal background wind below 20 km,and then,with the increase of height,the monthly averaged zonal wind exhibits a semiannual oscillation.The tropopause is in a height range of 5～13 km,and its monthly averaged height shows an annual cycle with the maximum at about 10 km in summer and the minimum at about 8.5 km in winter.An obvious annual cycle can be seen in the background temperature from the troposphere to the lower stratosphere,which is different from the results at middle and low latitudes.By combining Lomb-Scargle spectrum and hodograph technique,the parameters of IGWs are estimated.The case analysis demonstrates that the lower stratospheric IGWs exhibit a feature of freely propagating waves.The statistical study indicates that the IGWs have the dominant horizontal and vertical wavelengths of 50～450 km and1～4 km,respectively,and the dominant intrinsic frequency being 1～2.5 times the inertia frequency.These values are slightly smaller than those observed at middle and low latitudes.The intrinsic phase speed is mainly in the range of-0.3～0 m·s~(-1) in the vertical direction,and in the range of-40～40 m·s~(-1) in both the zonal and meridional directions.About 91.5%of the IGWs propagate upward,while in winter and early spring,the downward propagating waves increase to about20% due to the activity of polar stratospheric vortex.Because of the filtering of the prevailing eastward zonal wind in the lower atmosphere,the IGWs in the lower stratosphere display a dominant direction of westward propagation.Wave energy is the maximum in winter and the minimum in summer,which is consistent with the results at middle and low latitudes in the northern hemisphere.This indicates that the IGW activity over the northern hemisphere is generally the strongest in winter and the weakest in summer.
引文
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Hei H,Tsuda T,Hirooka T.2008.Characteristics of atmospheric gravity wave activity in the polar regions revealed by GPS radio occultation data with CHAMP.Journal of Geophysical Research,113(D4):D04107,doi:10.1029/2007JD008938.
Hu X,Liu A Z,Gardner C S,et al.2002.Characteristics of quasimonochromatic gravity waves observed with Na lidar in the mesopause region at Starfire Optical Range,NM.Geophysical Research Letters,29(24):22-1-22-4.
Huang K M,Zhang S D,Yi F.2008.Propagation and reflection of gravity waves in a meridionally sheared wind field.Journal of Geophysical Research,113:D09106,doi:10.1029/2007JD008877.
Huang K M,Zhang S D,Yi F.2009.Gravity wave excitation through resonant interaction in a compressible atmosphere.Geophysical Research Letters,36(1):L01803,doi:10.1029/2008GL035575.
Huang K M,Zhang S D,Yi F.2010.Reflection and transmission of atmospheric gravity waves in a stably sheared horizontal wind field.Journal of Geophysical Research,115(D16):D16103,doi:10.1029/2009JD012687.
Huang K M,Zhang S D,Yi F,et al.2013.Third-order resonant interaction of atmospheric gravity waves.Journal of Geophysical Research,118(5):2197-2206.
Huang K M,Liu A Z,Zhang S D,et al.2017.Simultaneous upward and downward propagating inertia-gravity waves in the MLT observed at Andes Lidar Observatory.Journal of Geophysical Research,122(5):2812-2830.
Leena P P,Venkat Ratnam M,Krishna Murthy B V.2012.Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station.Journal of Atmospheric and Solar-Terrestrial Physics,84-85:37-44.
Li T,She C Y,Liu H L,et al.2007.Sodium lidar-observed strong inertia-gravity wave activities in the mesopause region over Fort Collins,Colorado(41°N,105°W).Journal of Geophysical Research,112(D22):D22104,doi:10.1029/2007JD008681.
Li Z,Robinson W A,Liu A Z.2009.Sources of gravity waves in the lower stratosphere above South Pole.Journal of Geophysical Research,114(D14):D14103,doi:10.1029/2008JD011478.
Liang C,Xue X H,Chen T D.2014.An investigation of the global morphology of stratosphere gravity waves based on COSMICobservations.Chinese Journal of Geophysics(in Chinese),57(11):3668-3678,doi:10.6038/cjg20141121.
Liu X,Yue J,Xu J Y,et al.2017.Variations of global gravity waves derived from 14years of SABER temperature observations.Journal of Geophysical Research,122(12):6231-6249.
Matsumura S,Zhang X D,Yamazaki K.2014.Summer Arctic atmospheric circulation response to spring Eurasian snow cover and its possible linkage to accelerated sea ice decrease.Journal of Climate,27(17):6551-6558.
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Murphy D J,Alexander S P,Klekociuk A R,et al.2014.Radiosonde observations of gravity waves in the lower stratosphere over Davis,Antarctica.Journal of Geophysical Research,119(21):11973-11996.
Nash J.2015.Measurement of upper-air pressure,temperature and humidity.Instruments and Observing Methods Report No.121:1-87.
Nath D,Ratnam M V,Rao V V M J,et al.2009.Gravity wave characteristics observed over a tropical station using highresolution GPS radiosonde soundings.Journal of Geophysical Research,114(D6):D06117,doi:10.1029/2008JD011056.
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Ratnam M V,Babu A N,Rao V V M J,et al.2008.MST radar and radiosonde observations of inertia-gravity wave climatology over tropical stations:Source mechanisms.Journal of Geophysical Research,113(D7):D07109,doi:10.1029/2007JD008986.
Scargle J D.1982.Studies in astronomical time series analysis.II:Statistical aspects of spectral analysis of unevenly spaced data.The Astrophysical Journal,263:835-853.
Vadas S L,Fritts D C,Alexander M J.2003.Mechanism for the Generation of Secondary Waves in Wave Breaking Regions.Journal of the Atmospheric Sciences,60(1):194-214.
Vincent R A,Alexander M J.2000.Gravity waves in the tropical lower stratosphere:An observational study of seasonal and interannual variability.Journal of Geophysical Research,105(D14):17971-17982,doi:10.1029/2000JD900196.
Wang L,Geller M A,Alexander M J.2005.Spatial and temporal variations of gravity wave parameters.Part I:Intrinsic frequency,wavelength,and vertical propagation direction.Journal of the Atmospheric Sciences,62(1):125-142.
Wang R,Zhang S D,Yang H G,et al.2012.Characteristics of mid-latitude planetary waves in the lower atmosphere derived from radiosonde data.Annales Geophysicae,30(10):1463-1477.
Xiao C Y,Hu X.2010.Analysis on the global morphology of stratospheric gravity wave activity deduced from the COSMICGPS occultation profiles.GPS Solutions,14(1):65-74.
Xu J Y,Li Q Z,Yue J,et al.2015.Concentric gravity waves over northern China observed by an airglow imager network and satellites.Journal of Geophysical Research,120(21):11058-11078.
Yamamori M,Sato K.2006.Characteristics of inertia gravity waves over the South Pacific as revealed by radiosonde observations.Journal of Geophysical Research,111(D16):D16110,doi:10.1029/2005JD006861.
Yang G T,Clemesha B,Batista P,et al.2010.Seasonal variations of gravity wave activity and spectra derived from sodium temperature lidar.Journal of Geophysical Research,115(D18):D18104,doi:10.1029/2009JD012367.
Yoshiki M,Sato K.2000.A statistical study of gravity waves in the polar regions based on operational radiosonde data.Journal of Geophysical Research,105(D14):17995-18011.
Yu C,Xue X H,Wu J F,et al.2017.Sensitivity of the quasibiennial oscillation simulated in WACCM to the phase speed spectrum and the settings in an inertial gravity wave parameterization.Journal of Advances in Modeling Earth Systems,9(1):389-403.
Zhang S D,Yi F.2004.A numerical study on global propagations and amplitude growths of large-scale gravity wave packets.Journal of Geophysical Research,109(D7):D07106,doi:10.1029/2003JD004429.
Zhang S D,Yi F.2007.Latitudinal and seasonal variations of inertial gravity wave activity in the lower atmosphere over central China.Journal of Geophysical Research,112(D5):D05109,doi:10.1029/2006JD007487.
Zhang S D,Yi F,Huang C M,et al.2012.High vertical resolution analyses of gravity waves and turbulence at a midlatitude station.Journal of Geophysical Research,117(D2):D02103,doi:10.1029/2011JD016587.
Zhang Y,Xiong J G,Wan W X.2011.Analysis on the global morphology of middle atmospheric gravity waves.Chinese Journal of Geophysics(in Chinese),54(7):1711-1717,doi:10.3969/j.issn.0001-5733.2011.07.003.
Zhang Y,Xiong J,Liu L,et al.2012.A global morphology of gravity wave activity in the stratosphere revealed by the 8-year SABER/TIMED data.Journal of Geophysical Research,117(D21):D21101,doi:10.1029/2012JD017676.
Zink F,Vincent R A.2001.Wavelet analysis of stratospheric gravity wave packets over Macquarie Island:1.Wave parameters.Journal of Geophysical Research,106(D10):10275-10288.
梁晨,薛向辉,陈廷娣.2014.基于COSMIC卫星观测数据的平流层重力波的全球分布特征研究.地球物理学报,57(11):3668-3678,doi:10.6038/cjg20141121.
张云,熊建刚,万卫星.2011.中层大气重力波的全球分布特征.地球物理学报,54(7):1711-1717,doi:10.3969/j.issn.0001-5733.2011.07.003.
Eckermann S D,Hirota I,Hocking W K.1995.Gravity wave and equatorial wave morphology of the stratosphere derived from long-term rocket soundings.Quarterly Journal of the Royal Meteorological Society,121(521):149-186.
Fritts D C,Alexander M J.2003.Gravity wave dynamics and effects in the middle atmosphere.Reviews of Geophysics,41(1):1003,doi:10.1029/2001RG000106.
Hei H,Tsuda T,Hirooka T.2008.Characteristics of atmospheric gravity wave activity in the polar regions revealed by GPS radio occultation data with CHAMP.Journal of Geophysical Research,113(D4):D04107,doi:10.1029/2007JD008938.
Hu X,Liu A Z,Gardner C S,et al.2002.Characteristics of quasimonochromatic gravity waves observed with Na lidar in the mesopause region at Starfire Optical Range,NM.Geophysical Research Letters,29(24):22-1-22-4.
Huang K M,Zhang S D,Yi F.2008.Propagation and reflection of gravity waves in a meridionally sheared wind field.Journal of Geophysical Research,113:D09106,doi:10.1029/2007JD008877.
Huang K M,Zhang S D,Yi F.2009.Gravity wave excitation through resonant interaction in a compressible atmosphere.Geophysical Research Letters,36(1):L01803,doi:10.1029/2008GL035575.
Huang K M,Zhang S D,Yi F.2010.Reflection and transmission of atmospheric gravity waves in a stably sheared horizontal wind field.Journal of Geophysical Research,115(D16):D16103,doi:10.1029/2009JD012687.
Huang K M,Zhang S D,Yi F,et al.2013.Third-order resonant interaction of atmospheric gravity waves.Journal of Geophysical Research,118(5):2197-2206.
Huang K M,Liu A Z,Zhang S D,et al.2017.Simultaneous upward and downward propagating inertia-gravity waves in the MLT observed at Andes Lidar Observatory.Journal of Geophysical Research,122(5):2812-2830.
Leena P P,Venkat Ratnam M,Krishna Murthy B V.2012.Inertia gravity wave characteristics and associated fluxes observed using five years of radiosonde measurements over a tropical station.Journal of Atmospheric and Solar-Terrestrial Physics,84-85:37-44.
Li T,She C Y,Liu H L,et al.2007.Sodium lidar-observed strong inertia-gravity wave activities in the mesopause region over Fort Collins,Colorado(41°N,105°W).Journal of Geophysical Research,112(D22):D22104,doi:10.1029/2007JD008681.
Li Z,Robinson W A,Liu A Z.2009.Sources of gravity waves in the lower stratosphere above South Pole.Journal of Geophysical Research,114(D14):D14103,doi:10.1029/2008JD011478.
Liang C,Xue X H,Chen T D.2014.An investigation of the global morphology of stratosphere gravity waves based on COSMICobservations.Chinese Journal of Geophysics(in Chinese),57(11):3668-3678,doi:10.6038/cjg20141121.
Liu X,Yue J,Xu J Y,et al.2017.Variations of global gravity waves derived from 14years of SABER temperature observations.Journal of Geophysical Research,122(12):6231-6249.
Matsumura S,Zhang X D,Yamazaki K.2014.Summer Arctic atmospheric circulation response to spring Eurasian snow cover and its possible linkage to accelerated sea ice decrease.Journal of Climate,27(17):6551-6558.
Moffat-Griffin T,Colwell S R.2017.The characteristics of the lower stratospheric gravity wavefield above Halley(75°S,26°W),Antarctica,from radiosonde observations.JournalofGeophysical Research,122(17):8998-9010.
Murphy D J,Alexander S P,Klekociuk A R,et al.2014.Radiosonde observations of gravity waves in the lower stratosphere over Davis,Antarctica.Journal of Geophysical Research,119(21):11973-11996.
Nash J.2015.Measurement of upper-air pressure,temperature and humidity.Instruments and Observing Methods Report No.121:1-87.
Nath D,Ratnam M V,Rao V V M J,et al.2009.Gravity wave characteristics observed over a tropical station using highresolution GPS radiosonde soundings.Journal of Geophysical Research,114(D6):D06117,doi:10.1029/2008JD011056.
Pramitha M,Venkat Ratnam M,Leena P P,et al.2016.Identification of Inertia Gravity Wave sources observed in the troposphere and the lower stratosphere over a tropical station Gadanki.Atmospheric Research,176-177:202-211.
Ratnam M V,Babu A N,Rao V V M J,et al.2008.MST radar and radiosonde observations of inertia-gravity wave climatology over tropical stations:Source mechanisms.Journal of Geophysical Research,113(D7):D07109,doi:10.1029/2007JD008986.
Scargle J D.1982.Studies in astronomical time series analysis.II:Statistical aspects of spectral analysis of unevenly spaced data.The Astrophysical Journal,263:835-853.
Vadas S L,Fritts D C,Alexander M J.2003.Mechanism for the Generation of Secondary Waves in Wave Breaking Regions.Journal of the Atmospheric Sciences,60(1):194-214.
Vincent R A,Alexander M J.2000.Gravity waves in the tropical lower stratosphere:An observational study of seasonal and interannual variability.Journal of Geophysical Research,105(D14):17971-17982,doi:10.1029/2000JD900196.
Wang L,Geller M A,Alexander M J.2005.Spatial and temporal variations of gravity wave parameters.Part I:Intrinsic frequency,wavelength,and vertical propagation direction.Journal of the Atmospheric Sciences,62(1):125-142.
Wang R,Zhang S D,Yang H G,et al.2012.Characteristics of mid-latitude planetary waves in the lower atmosphere derived from radiosonde data.Annales Geophysicae,30(10):1463-1477.
Xiao C Y,Hu X.2010.Analysis on the global morphology of stratospheric gravity wave activity deduced from the COSMICGPS occultation profiles.GPS Solutions,14(1):65-74.
Xu J Y,Li Q Z,Yue J,et al.2015.Concentric gravity waves over northern China observed by an airglow imager network and satellites.Journal of Geophysical Research,120(21):11058-11078.
Yamamori M,Sato K.2006.Characteristics of inertia gravity waves over the South Pacific as revealed by radiosonde observations.Journal of Geophysical Research,111(D16):D16110,doi:10.1029/2005JD006861.
Yang G T,Clemesha B,Batista P,et al.2010.Seasonal variations of gravity wave activity and spectra derived from sodium temperature lidar.Journal of Geophysical Research,115(D18):D18104,doi:10.1029/2009JD012367.
Yoshiki M,Sato K.2000.A statistical study of gravity waves in the polar regions based on operational radiosonde data.Journal of Geophysical Research,105(D14):17995-18011.
Yu C,Xue X H,Wu J F,et al.2017.Sensitivity of the quasibiennial oscillation simulated in WACCM to the phase speed spectrum and the settings in an inertial gravity wave parameterization.Journal of Advances in Modeling Earth Systems,9(1):389-403.
Zhang S D,Yi F.2004.A numerical study on global propagations and amplitude growths of large-scale gravity wave packets.Journal of Geophysical Research,109(D7):D07106,doi:10.1029/2003JD004429.
Zhang S D,Yi F.2007.Latitudinal and seasonal variations of inertial gravity wave activity in the lower atmosphere over central China.Journal of Geophysical Research,112(D5):D05109,doi:10.1029/2006JD007487.
Zhang S D,Yi F,Huang C M,et al.2012.High vertical resolution analyses of gravity waves and turbulence at a midlatitude station.Journal of Geophysical Research,117(D2):D02103,doi:10.1029/2011JD016587.
Zhang Y,Xiong J G,Wan W X.2011.Analysis on the global morphology of middle atmospheric gravity waves.Chinese Journal of Geophysics(in Chinese),54(7):1711-1717,doi:10.3969/j.issn.0001-5733.2011.07.003.
Zhang Y,Xiong J,Liu L,et al.2012.A global morphology of gravity wave activity in the stratosphere revealed by the 8-year SABER/TIMED data.Journal of Geophysical Research,117(D21):D21101,doi:10.1029/2012JD017676.
Zink F,Vincent R A.2001.Wavelet analysis of stratospheric gravity wave packets over Macquarie Island:1.Wave parameters.Journal of Geophysical Research,106(D10):10275-10288.
梁晨,薛向辉,陈廷娣.2014.基于COSMIC卫星观测数据的平流层重力波的全球分布特征研究.地球物理学报,57(11):3668-3678,doi:10.6038/cjg20141121.
张云,熊建刚,万卫星.2011.中层大气重力波的全球分布特征.地球物理学报,54(7):1711-1717,doi:10.3969/j.issn.0001-5733.2011.07.003.