• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Spectrum Analysis of Wind Profiling Radar Measurements

    2014-12-14 06:58:12RUANZheng阮征MURuiqi慕瑞琪WEIMing魏鳴andGERunsheng葛潤生
    Journal of Meteorological Research 2014年4期

    RUAN Zheng(阮征),MU Ruiqi(慕瑞琪),WEI Ming(魏鳴),and GE Runsheng(葛潤生)

    1 State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081

    2 Nanjing University of Information Science&Technology,Nanjing 210044

    Spectrum Analysis of Wind Profiling Radar Measurements

    RUAN Zheng1?(阮征),MU Ruiqi2(慕瑞琪),WEI Ming2(魏鳴),and GE Runsheng1(葛潤生)

    1 State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081

    2 Nanjing University of Information Science&Technology,Nanjing 210044

    Unlike previous studies on wind turbulence spectrum in the planetary boundary layer,this investigation focuses on high-altitude(1-5 km)wind energy spectrum and turbulence spectrum under various weather conditions.A fast Fourier transform(FFT)is used to calculate the wind energy and turbulence spectrum density at high altitudes(1-5 km)based on wind profiling radar(WPR)measurements.The turbulence spectrum under stable weather conditions at high altitudes is expressed in powers within a frequency range of 2×10-5-10-3s-1,and the slope b is between-0.82 and-1.04,indicating that the turbulence is in the transition from the energetic area to the inertial sub-range.The features of strong weather are reflected less obviously in the wind energy spectrum than in the turbulence spectrum,with peaks showing up at different heights in the latter spectrum.Cold windy weather appears over a period of 1.5 days in the turbulence spectrum.Wide-range rainstorms exhibit two or three peaks in the spectrum over a period of 15-20 h, while in severe convective weather conditions,there are two peaks at 13 and 9 h.The results indicate that spectrum analysis of wind profiling radar measurements can be used as a supplemental and helpful method for weather analysis.

    wind profiling radar,wind energy spectrum,turbulence spectrum

    1.Introduction

    Wind measurements can be analyzed by using two methods associated with Fourier transforms.The time-domain method studies energy changes with time,while the frequency-domain method studies the distribution of energy with frequency.

    Panofsky(1955)and Griffith et al.(1956)employed the power-spectrum density analysis to study the spectral characteristics of boundary layer wind. Van der Hoven(1957)performed a power-spectrum analysis of horizontal wind over a wide range of frequencies.These studies showed that there appears to be two major eddy-energy peaks in the spectrum:one peak at a period of 4 days and the other at a period of 1 min.Between the two peaks,a broad spectral gap is centered at a frequency ranging from 1 to 10 cycles per hour(Atkinoon,1981).Since the 1970s,spectrum analysis has been applied in boundary layer turbulence studies(Endlich et al.,1969;Bowne and Ball, 1970;Kaimal et al.,1972).H?jstrup(1981)developed a distribution model of the turbulence spectrum in neutral and unstable stratification,and this has since been widely used.Panofsky et al.(1982)showed that the distribution of turbulence spectrum varies for different topographies.Recently,Chellali et al.(2010) proposed that the features of turbulence spectrum are affected by topography and spatial location.

    In-depth research has been carried out on turbulence spectrum analysis,mainly in boundary layer wind measurements.Zhang et al.(1987)used observations of horizontal wind speed from a 320-m meteorological tower to analyze the spectral characteristics and vertical distribution of turbulence in the boundary layer,and concluded that in the atmosphere,under both stable and unstable stratification,there are sev-

    eral cycles at a period of a few minutes to 10 minutes.Bian et al.(2002)discovered that the turbulence spectrum characteristics of the boundary layer are consistent with Kolmogorow’s“-5/3 rate,”(Kolmogorov,1941a,b)and confirmed that the power exponent and exponent function are more appropriate. Wang and Mao(2004)used wavelets to analyze the turbulence spectrum characteristics of a convective βscale weather system.Spectral analysis has also been applied to cold windy weather(Luo and Zhu,1993; Liu and Hong,1996;Tian et al.,2011)and cold fronts (Zhao et al.,1982;Sun and Xu,1997).

    Supported by the National Natural Science Foundation of China(41075023 and 41475029),China Meteorological Administration Special Public Welfare Research Fund(GYHY201306004),and Key Technology Integration and Application Fund of the China Meteorological Administration(CMAGJ2013M74).

    ?Corresponding author:ruanz@cams.cma.gov.cn.

    ?The Chinese Meteorological Society and Springer-Verlag Berlin Heidelberg 2014

    Due to the absence of refined wind measurements,analysis of the energy spectrum and turbulence spectrum in the atmospheric layer above the boundary layer is limited.By applying wind profile radar (WPR)in atmospheric soundings(Liu et al.,2003),it is possible to obtain high-altitude wind data on a continuous basis.Research on the energy spectrum and turbulence spectrum based on high-reliability WPR measurements at altitudes of 1-5 km has thus been developed(Wang et al.,2007;Wei and Zhang,2009;Sun et al.,2012;Yu,2012).This study aims to provide a statistical analysis of wind energy and turbulence spectrum at 1-5-km heights under various weather conditions.

    2.Method

    Spectral analysis,which is expressed by frequency or wavenumber,is a statistical tool to study signal properties.The Parseval equation is as follows:

    where ω is the angular frequency and f is the frequency.Then,S(ω)=|F(ω)|2,where S(ω)is the energy spectrum density,indicating the contribution fluctuation makes to the total energy.

    The energy spectrum density estimates are calculated by using the Fourier transform.The autocorrelation function is defined as

    in which S(f)=|F(f)|2.

    The energy spectrum density estimate is

    To reduce the leakage effect caused by the Fourier transform,an appropriate window should be chosen.

    2.1 Wind energy spectrum analysis

    In this study,the horizontal wind-speed data used in the wind energy spectrum analysis are obtained from WPR measurements.The autocorrelation function of the time-domain data Vh(t)is

    and the Fourier transform for the autocorrelation function is the unit volume energy spectrum density,

    where the unit of frequency f is s-1,the unit of air density ρ is kg m-3,and the unit of horizontal wind speed Vhis m s-1.The change of air density with height must be considered in the wind energy spectrum analysis of high-altitude wind data.Let SVh(f) be the energy density of horizontal wind speed,it can be calculated ass;then,the unit of the unit volume energy spectrum density can be given as(kg m-3)(m2s-1).

    The wind energy spectra are used to characterize the variation of the wind energy density with frequency,and they are considered to be related to various weather systems.

    2.2 Turbulence spectrum analysis

    Irregular fluctuation is the basic characteristic of turbulence.Horizontal wind can be calculated as

    According to Kolmogorov’s theory(Kolmogorov, 1941a,b),the inertial sub-range is a turbulence region where the Reynolds number is large enough to meet local homogeneous isotropic conditions,so its turbulence characteristics only depend on the dissipation rate.The energy spectral function is defined by

    where k is the wavenumber,ε is the turbulence dissipation rate,and C is a constant.The function is called the“-5/3 law.”The inertial sub-range of the turbulence energy spectrum can also be expressed by frequency(Sheng et al.,2003):

    where S(f)is the turbulence spectrum density.The turbulence spectrum analysis using wind tower observations shows that the slope of the turbulence spectrum at frequencies between 10-2and 102is-5/3 in the inertial sub-range(Bian et al.,2002).

    Figure 1 shows the turbulence spectrum changes with wave number(Tian et al.,2011).The spectrum can be divided into five ranges:the dissipation range, the inertial sub-range,the energy range,the largest vortex range,and the large eddy range.The energy range produces turbulent energy,which can neither be generated nor be dissipated but is transferred to smaller scales of motion in the inertial sub-range or changed into internal energy because of the viscosity of the fluid molecules in the dissipative range.In the inertial sub-range,the slope of the turbulence spectrum is-5/3,which is steeper than the slope in the energy range but shallower than in the dissipation range (Kaimal and Finnigan,1994).The turbulence spectrum density is normalized as:whereexpresses the variance of wind fluctuation.

    2.3 The trend in the turbulence spectrum

    The average wind data are usually treated as the mean wind for data collected over a short period.However,the mean wind for wind data collected over long periods changes with time,and is called the trend. The fluctuation of the wind is obtained by using the least-square curve fitting to calculate the trend and deduct it from the wind data.Figure 2 shows the turbulence spectrum with two different methods used for the mean wind calculation.In Fig.2a,the average wind data are treated as the mean wind and in Fig. 2b the trend is calculated as the mean wind.The data are on 23 June 2011.Figure 2b shows a more distinct 28-h eddy energy.

    3.Equipment and data processing

    3.1 Instruments

    The horizontal wind-speed data used in the spectral analysis are obtained from CFL-08 troposphere wind profiler radar,which is located at Yanqing,Beijing(40.45°N,115.96°E;487.90-m elevation).Table 1 summarizes the main properties of the radar.Rigorous calibration and standardization were carried out on the wind profile radar.Compared with air sounding,the accuracy of the wind profile radar corresponds with the specification.Deng et al.(2012)evaluated the detection accuracy of the radar using observations in 2010.

    3.2 Data processing

    Fig.1.Turbulence spectrum changes with wavenumber. (From Tian et al.,2011)

    Fig.2.The turbulent spectra obtained with mean wind derived differently.(a)Average as mean wind and(b)trend as mean wind.

    Table 1.Parameters of the CFL-08(troposphere II) wind profiling radar

    The wind profile radar provides horizontal windspeed data and signal-to-noise ratio(SNR),echo intensity,spectral width,and so on.The data were obtained from December 2010 to October 2012,at a sampling interval of 6 min.Quality control was applied as follows.Wind data that had an SNR of less than -15 dB were removed from the energy spectrum analysis because of their inaccuracy. Data series that had five consecutive missing data points were rejected. When individual missing data occurred in the data sequence,neighboring data were used to fill the gap by using linear interpolation.

    According to the duration of different disastrous weather events,the data length chosen for cold windy weather and summer rainstorms is 7 days,while 3 days is chosen for severe convective weather.The trend is identified in the turbulence spectrum density calculation.Data used for the turbulence spectrum features of the stable weather analysis are detected every 6 min for a period of 24 h.

    4.Characteristics of turbulence spectrum at high altitude

    To examine the characteristics of the turbulence spectrum at high altitude,10 sets of wind data under stable weather conditions are chosen.The data period is 24 h and the frequency range is from 10-5to 10-2s-1.Figure 3 shows the normalized turbulence spectrum on 28 January 2011 at an altitude of 1110 m.The abscissa is frequency and the ordinate is normalized turbulence spectrum density.Logarithmic coordinates have been used.

    Figure 3 shows that the distribution of the turbulence spectrum is linear.By using least-square linear fitting,the turbulence spectrum density in the frequency range 2×10-5-10-3s-1can be expressed as

    where a is the intercept of the abscissa,which is related to the turbulence dissipation rate;and b is the slope.The parameters of the turbulence spectrum for Fig.3 are a=9×10-4,b=-0.93,and the fitting

    Fig.3.Turbulence spectrum features on 28 January 2011. rate is 0.99.

    Table 2 summarizes the values of a and b for the turbulence spectrum of the 10 sets of data under stable weather conditions at different heights:a varies from 4×10-4to 4×10-3and b varies from-0.82 to-1.04,which is less than the value(-5/3)in the inertial sub-range.The turbulence spectrum distributes in power in the frequency ranges of 2×10-5-10-3s-1at heights between 1000 and 5000 m;b is less than -5/3,showing that the turbulence is in the energy region that is transiting to the inertial sub-range.

    The turbulence spectrum density of horizontal wind speed and its two orthogonal components u and v have been calculated.Figure 4 shows the turbulence spectrum of the horizontal wind speed,Vh,u,and v on 1 December 2012 at an altitude of 1110 m.The results indicate that the three variables have a characteristic in common.The slope b is-0.96,-0.97,and-0.97,in the frequency range of 2×10-5-10-3s-1.It can then be concluded that the distribution of the turbulence spectrum in stable weather cases does not depend on the wind direction.

    However,the situation is different for rainy days. Figure 5 shows the distributions of the turbulencespectrum for different variables at an altitude of 1110 m in severe convective weather cases at 0000-2400 BT (Beijing Time)3 June 2012.The slope b is-0.54, -0.79,and-0.76,which are quite different to those for stable weather cases.

    Table 2.Values of the turbulence spectrum parameters a and b and the fitting rate R under stable weather cases

    Fig.4.Turbulence spectrum features of different variables at 1110-m height under stable weather on 1 December 2012. (a)u,(b)v,and(c)Vh.

    Fig.5.Turbulence spectrum features of different variables at 1110-m height under rainy weather on 3 June 2012. (a)u,(b)v,and(c)Vh.

    5.Spectrum characteristics in various weather conditions

    5.1 Wind energy spectrum under stable weather conditions

    The wind energy spectrum in stable weather conditions is calculated as follows.The observations from 0000 BT 5 to 2400 BT 11 December 2010,and 0000 BT 3 to 2400 BT 5 July 2010 are chosen as typical examples of winter and summer weather conditions. Figure 6 shows that there is no peak during these periods,and the distribution of energy spectrum in the whole frequency band is relatively flat.The energy spectrum density decreases with increasing frequency. Figure 6 also shows that at the same height,the wind energy spectrum density in summer is nearly one order of magnitude smaller than in winter.The value decreases homogeneously with the reducing height in winter,while in summer it is dense in the altitude range of 1000-2000 m.The distribution of the spectrum in the two seasons is similar,as is the normalized turbulence spectrum in stable weather cases.

    Table 3 gives a summary of the spectral density of horizontal wind at five heights in stable weather.As the height reduces from 5000 to 1000 m,the wind energy spectrum density decreases by one order of magnitude in winter,which is the same as that shown in Fig.6.In summer,the spectral density decreases by half.Overall,the spectral density change with height is greater in winter than in summer.

    Fig.6.Wind energy spectrum features for stable weather cases.(a)5-11 December 2012 and(b)3-5 July 2010.

    Table 3.Spectral density of horizontal wind at five heights in stable weather

    The turbulence spectrum density accounting for the proportion of wind energy spectrum density increases with frequency,as shown in Table 3.As the height reduces,the ratio becomes greater as well,and this characteristic is more obvious in summer.

    5.2 Spectrum characteristics of cold windy weather

    The data used in the spectrum analysis of cold windy weather are from the Beijing wind profile radar. The sampling interval is 30 min and the data period is 7 days.On 11 November 2012,winds at level 5 or 6 were observed in Beijing;in some local areas,winds even reached level 7,and then weakened to level 3 at night with significant cooling.Figure 7a shows the horizontal wind speed below the altitude of 5000 m, Fig.7b shows the wind energy spectrum,and Fig. 7c shows the turbulence spectrum,for this cold windy weather.The five curves represent the spectrum density at 5070,4110,3150,2190,and 1110 m.

    The different appearance of the wind energy spectrum for cold windy and stable weather in winter can be seen in Fig.7b.At the altitude range of 5070-2190 m,the energy spectrum density only changes a little, while it decreases rapidly in the range of 2190-1110 m. This is different from the changes in stable weather.In the turbulence spectrum(Fig.7c),compared with the stable weather,there is a clear peak at the frequency 3.0×10-5s-1.The intensity of the peak gradually decreases from 5070 to 2190 m.

    Fig.7.(a)Horizontal wind speed,(b)wind energy spectrum of horizontal wind,and(c)turbulent spectrum of horizontal wind,under cold windy weather during 8-14 November 2012.

    Table 4 gives the spectral density of horizontal wind at five heights in cold windy weather.There appears to be a transmission of the energy spectrum density from high to low altitudes.From 5070 to 2190 m,the energy spectrum density decreases quickly and then increases slowly.In the peak area,the turbulence spectrum density accounting for the proportion of the wind energy spectrum density increases rapidly;the higher the height,the higher the proportion.The ratios at the five heights are 22.4%,12.8%,9.6%,8.8%, and 7.3%,respectively.

    Table 4 and Fig.7 show that there is a period of 1.5 days in cold windy weather where the wind energy spectrum from 5070 to 2190 m decreases quickly and then increases slowly.A strong wind shear caused the intense turbulence.The amplitude in the peak area at high altitude is greater than at the lower levels.This may be due to the energy passing from the upper air

    to the lower levels.

    Table 4.Spectral density of horizontal wind at five heights in cold windy weather

    5.3 Spectrum characteristics of summer rainstorms

    Compared with the stable weather,the turbulence spectrum during summer rainstorms has several peaks.This is the turbulence characteristics of the mesoscale rainstorm weather.On 23 June 2011, heavy rain fell in the Beijing area;total 24-h rainfall reached 241 mm.The rainstorm was sudden and intense.It had an uneven spatial distribution and significant mesoscale characteristics.The precipitation was concentrated in the period 16-19 h,with many areas experiencing instantaneous hail.Figure 8a shows the horizontal wind speed below the altitude of 5000 m from 0000 BT 20 to 2400 BT 26 June 2011.Figures 8b and 8c show the wind energy spectrum and the turbulence spectrum for this rainstorm.

    The wind energy spectrum(Fig.8b)shows that the amplitude decreases as the height reduces.In contrast to the spectrum in cold windy weather,the wind energy spectrum becomes more stable with height,and the slope of the wind energy spectrum decreases with decreasing height.The spectrum density is only 20% of that in cold windy weather at the same altitude. There are 2-3 peaks at different heights in Fig.8c. The peaks are located in the frequency range of 7× 10-6-2×10-5s-1,and have a period of about 1 day. It can be seen that at 1110 m,there are two peaks located at 5×10-6and 2×10-5s-1,while there are no peaks at 2190 m.

    Table 5 gives the spectral density of horizontal wind at five heights in the summer rainstorm case. The characteristic of spectral density changing with height is similar to that in stable weather.The turbulence spectrum density accounting for the proportion of wind energy spectrum density significantly increases

    in peak areas,which reflects that there are several disturbances in the rainstorm which occurred in the warm sector and there was no cold air at upper levels.The occurrence of the peaks may be because of the vertical movement of precipitation clouds.

    Fig.8.As in Fig.7,but for summer rainstorms during 8-14 June 2011.

    Table 5.Spectral density of horizontal wind at five heights in the summer rainstorm case

    5.4 Spectrum characteristics of severe convective weather

    On 3 June 2012,hailstorms,possibly due to trough-line activities,occurred in Beijing,with more than 20 mm of precipitation.Figure 9a shows the horizontal wind speed below the altitude of 5000 m during 3-5 June 2012. Figure 9b shows the wind energy spectrum and Fig.9c shows the turbulence spectrum for this severe convective weather case.

    Fig.9.As in Fig.7,but for the severe convective weather case during 3-5 June 2012.

    In Fig.9b,the spectrum is smooth and there are no peaks.The amplitude is four times bigger than in the summer rainstorm,and is close to that in cold windy weather.From 5070 to 3150 m,the spectrum

    density decreases only a little,while it reduces rapidly below 3150 m,showing that the wind energy transmits faster at the lower level.The spectrum characteristics are similar to those of cold windy weather because the two cases are both related to a cold front.The spectrum of turbulence has two peaks at all the heights except 2190 m;one at a frequency of 2×10-5s-1and the other at 6×10-5s-1.These peaks occur at about 13 and 9 h.The amplitude of the peaks is stronger at low altitude.The maximum amplitude is at 3150 m and the minimum is at 5070 m,which shows that the turbulence is more vigorous at 3000 m. This may be because of the activity of the trough-line. The amplitude at 1110 m is larger than that at 5070 m,mainly because of the activity of turbulence in the warm sector.

    Table 6 is a summary of the spectral density of horizontal wind at five heights in this severe convective weather case.The spectral density decreases with decreasing altitude.The amplitude of the spectrum at the same altitude and the same frequency in severe convective weather is larger than that in stable weather.The higher the frequency,the less the spectrum density,and the larger the turbulence spectrum density accounting for the proportion of the wind energy spectrum density,indicating that the energy in the high energy scale at low frequency transmits to the low energy scale at high frequency.In peak areas,the turbulence spectrum density accounting for the proportion of the wind energy spectrum density is larger than other areas,especially at 3150 and 2190 m. This may be because of the intense vertical movementat the middle level.

    Table 6.Spectral density of horizontal wind at five heights in the case of severe convective weather

    6.Summary and conclusions

    In this study,spectral analysis of wind profiling radar observations at heights of 1-5 km has been made.The wind energy and turbulence spectrum in different weather conditions shows different characteristics,which are helpful to the analysis and research of weather systems.

    Turbulence spectrum in stable weather conditions at high altitude is expressed in powers in the frequency range 2× 10-5-10-3s-1.The slope b is between -0.82 and-1.04,indicating that the turbulence is in the transition zone from the energetic range to the inertial sub-range.Wind shear and convective activity may enhance the turbulence.

    The peaks seen in the turbulence spectrum show the period of the weather system.Cold windy weather appears at a period of 1.5 days in the turbulence spectrum,and the amplitude at 5 km is the largest.The wide-range summer rainstorm exhibits two or three peaks in the spectrum over 15-20 h.In the severe convective weather conditions there are two peaks at 13 and 9 h.

    Compared with stable weather,the turbulence spectrum density accounting for the proportion of the wind energy spectrum density increases rapidly,especially in peak areas,in severe weather conditions.

    Atkinoon,B.W.,1981:Mesoscale Atmospheric Circulations.Academic Press,495 pp.

    Bian Jianchun,Qiao Jinsong,and Lu Daren,2002:Laboratory for middle atmosphere and global environment observation.Chinese J.Atmos.Sci.,26,474-480.(in Chinese)

    Bowne,N.E.,and J.T.Ball,1970:Observational comparison of rural and urban boundary layer turbulence.J.Appl.Meteor.,9,862-873.

    Chellali,F.,A.Khellaf,and B.Adel,2010:Application of time-frequency representation in the study of the cyclical behavior of wind speed in Algeria:Wavelet transform.Stochastic Environmental Research and Risk Assessment,24,1233-1239.

    Deng Chuang,Ruan Zheng,Wei Ming,et al.,2012:The evaluation of wind measurement accuracy by wind profile radar.J.Appl.Meteor.Sci.,23,523-533. (in Chinese)

    Endlich,R.M.,R.C.Singleton,and J.W.Kaufman, 1969:Spectral analysis of detailed vertical wind speed profiles.J.Atmos.Sci.,26,1030-1041.

    Griffith,H.L.,H.A.Panofsky,and I.van der Hoven., 1956:Power-spectrum analysis over large ranges of frequency.J.Atmos.Sci.,13,279-282.

    H?jstrup,J.,1981:A simple model for the adjustment of velocity spectra in unstable conditions downstream of an abrupt change in roughness and heat flux. Bound.-Layer Meteor.,21,341-356.

    Kaimal,J.C.,J.C.Wyngaard,Y.Izumi,et al,1972: Spectral characteristics of surface layer turbulence. Quart.J.Roy.Meteor.Soc.,98,563-589.

    —-,and J.J.Finnigan,1994:Atmospheric Boundary Layer Flows:Their Structure and Measurement. Oxford University Press,1-279.

    Kolmogorov,A.N.,1941a:The local structure of turbulence in incompressible viscous fluid for very large Reynolds number.Math.Phys.Sci.,434,9-13.

    —-,1941b:Dissipation of energy in the locally isotropic turbulence.Math.Phys.Sci.,434,15-17.

    Liu Shuyuan,Zheng Yongguang,and Tao Zuyu,2003: The analysis of the relationship between pulse of land heavy rain using wind profiler data.J.Trop. Meteor.,19,285-290.(in Chinese)

    Liu Xiaohong and Hong Zhongxiang,1996:A study of the structure of a strong wind event in the atmospheric boundary layer in Belting area. Scientia Meteor.Sinica,20,223-228.(in Chinese)

    Luo Jianyuan and Zhu Ruizhao,1993:The analysis of wind spectrum characteristics in surface layer in Badaling area of Beijing. Acta Energiae Solaris Sinica,14,279-287.(in Chinese)

    Panofsky,H.A.,1955:Meteorological applications of power—Spectrum analysis.Bull.Amer.Mcteor. Soc.,36,163-166.

    —-,D.Larko,R.Lipschutz,et al.,1982:Spectra of velocity components over complex terrain.Quart.J. Roy.Meteor.Soc.,108,215-230.

    Sheng Peixuan,Mao Jietai,Li Jianguo,et al.,2003: Atmospheric Physics.Beijing University Press,Beijing,227-228.(in Chinese)

    Sun Aidong and Xu Yumao,1997:Spectral characteristic and multi-scale analysis of a wet cold front in boundary-layer atmosphere. Scientia Atmos. Sinica,17,18-27.(in Chinese)

    Sun Jisun,He Na,Wang Guorong,et al.,2012:Preliminary analysis on synoptic configuration evolvement and mechanism of a torrential rain occurring in Beijing on 21 July 2012.Torrential Rain and Disasters, 31,218-225.(in Chinese)

    Tian Yuji,Yang Qingshan,Yang Na,et al.,2011:Beijing meteorological tower statistical model of turbulent wind velocity spectrum.Scientia Sinica(Technologica),41,1460-1468.(in Chinese)

    Van der Hoven,I.,1957:Power spectrum of horizontal wind speed in the frequency range from 0.0007 to 900 cycles per hour.J.Meteor.,14,160-164.

    Wang Hua,Sun Jisong,and Li Jin,2007:A comparative analysis on two severe hail events in Beijing urban district in 2005.Meteor.Mon.,33,49-56.(in Chinese)

    Wang Xinyan and Mao Jietai,2004:The wavelet application in the research of mesoscale convective activity features.J.Trop.Meteor.,20,549-560.(in Chinese)

    Wei Fengying and Zhang Ting,2009:Frequency distribution of drought intensity in Northeast China and relevant circulation background.Journal of Natural Disasters,18,1-7.(in Chinese)

    Yu Xiaoding,2012: Investigation of Beijing extreme flooding event on 21 July 2012.Meteor.Mon.,38, 1313-1329.(in Chinese)

    Zhang Xiaoping,L¨u Naiping,and Zhou Mingyu,1987: The characteristics of vertical distribution of lowfrequency spectra for horizontal wind velocity in the atmospheric boundary layer.Chinese J.Atmos. Sci.,11,31-39.(in Chinese)

    Zhao Deshan,Wang Lizhi,and Hong Zhongxiang,1982: Analysis on the structure of gust in boundary layer when a cold front passing.Chinese J.Atmos.Sci., 6,324-332.(in Chinese)

    :Ruan Zheng,Mu Ruiqi,Wei Ming,et al.,2014:Spectrum analysis of wind profiling radar measurements.J.Meteor.Res.,28(4),656-667,

    10.1007/s13351-014-3171-y.

    (Received November 12,2013;in final form May 19,2014)

    又爽又黄a免费视频| av国产免费在线观看| 免费av毛片视频| 搡老乐熟女国产| 美女cb高潮喷水在线观看| 中文字幕亚洲精品专区| 黄色配什么色好看| 精品久久久久久久久亚洲| 国产精品精品国产色婷婷| 国产精品99久久99久久久不卡 | 在线观看av片永久免费下载| 亚州av有码| 毛片一级片免费看久久久久| 亚洲国产精品国产精品| 欧美最新免费一区二区三区| 九九久久精品国产亚洲av麻豆| 国产黄片视频在线免费观看| 国产亚洲一区二区精品| 91狼人影院| 男人舔奶头视频| 日本猛色少妇xxxxx猛交久久| 国产亚洲av嫩草精品影院| 别揉我奶头 嗯啊视频| 日韩国内少妇激情av| 久久99精品国语久久久| 午夜亚洲福利在线播放| 亚洲成人一二三区av| 中文资源天堂在线| 汤姆久久久久久久影院中文字幕| 91久久精品国产一区二区三区| av女优亚洲男人天堂| 亚洲av成人精品一区久久| 欧美区成人在线视频| 亚洲怡红院男人天堂| 国产成人免费无遮挡视频| 国产精品久久久久久久久免| 不卡视频在线观看欧美| 精品人妻视频免费看| 深爱激情五月婷婷| 亚洲国产成人一精品久久久| 国产高清不卡午夜福利| 亚洲自偷自拍三级| 精品人妻熟女av久视频| 中国美白少妇内射xxxbb| 亚洲精品自拍成人| 天美传媒精品一区二区| 亚洲精品乱码久久久v下载方式| 免费大片黄手机在线观看| 哪个播放器可以免费观看大片| 偷拍熟女少妇极品色| a级毛色黄片| 熟女av电影| 欧美精品人与动牲交sv欧美| 青春草亚洲视频在线观看| 免费在线观看成人毛片| 精品少妇黑人巨大在线播放| 九九久久精品国产亚洲av麻豆| 91精品伊人久久大香线蕉| 精品99又大又爽又粗少妇毛片| 国产精品一区二区三区四区免费观看| 七月丁香在线播放| 国语对白做爰xxxⅹ性视频网站| 涩涩av久久男人的天堂| av网站免费在线观看视频| 国产男女内射视频| 韩国高清视频一区二区三区| 人妻制服诱惑在线中文字幕| 久久久久久伊人网av| 性插视频无遮挡在线免费观看| 亚洲不卡免费看| 老司机影院毛片| av免费观看日本| 爱豆传媒免费全集在线观看| 一级二级三级毛片免费看| 色播亚洲综合网| 春色校园在线视频观看| 一本一本综合久久| 亚洲精品成人av观看孕妇| 亚洲精品中文字幕在线视频 | 国产有黄有色有爽视频| 两个人的视频大全免费| 亚洲熟女精品中文字幕| 亚洲av福利一区| 久久99热这里只频精品6学生| 一本一本综合久久| 久久久久久久大尺度免费视频| 国产免费又黄又爽又色| 黄色日韩在线| 亚洲成人精品中文字幕电影| 国产男女内射视频| 午夜老司机福利剧场| 新久久久久国产一级毛片| 99视频精品全部免费 在线| 国产精品国产三级国产av玫瑰| 男人和女人高潮做爰伦理| 联通29元200g的流量卡| 国产真实伦视频高清在线观看| 69人妻影院| 99热这里只有精品一区| 成人免费观看视频高清| 欧美日韩视频精品一区| 啦啦啦中文免费视频观看日本| 干丝袜人妻中文字幕| 中文资源天堂在线| 久久久久久伊人网av| 亚洲四区av| 真实男女啪啪啪动态图| 国产高潮美女av| 激情五月婷婷亚洲| 高清毛片免费看| 精品国产一区二区三区久久久樱花 | 欧美人与善性xxx| 午夜福利高清视频| 国产精品精品国产色婷婷| 欧美3d第一页| 久久久久久久久久久免费av| 亚洲国产欧美在线一区| 春色校园在线视频观看| kizo精华| 久久精品久久久久久噜噜老黄| 国模一区二区三区四区视频| 国产欧美日韩精品一区二区| 国产精品国产三级专区第一集| 色视频在线一区二区三区| 亚洲不卡免费看| 精品熟女少妇av免费看| 国产综合精华液| 中文字幕制服av| 精品国产露脸久久av麻豆| 九色成人免费人妻av| 最近手机中文字幕大全| 国产在线男女| 免费av毛片视频| 在线免费十八禁| 在线播放无遮挡| 精华霜和精华液先用哪个| 天天躁日日操中文字幕| 久久精品熟女亚洲av麻豆精品| 汤姆久久久久久久影院中文字幕| 午夜老司机福利剧场| 精品视频人人做人人爽| 精华霜和精华液先用哪个| 毛片一级片免费看久久久久| 美女被艹到高潮喷水动态| 黄片无遮挡物在线观看| 亚洲va在线va天堂va国产| 精品一区二区三卡| 国产 一区精品| 久久午夜福利片| 精品一区二区三卡| 在线观看一区二区三区| 国产 精品1| 中国美白少妇内射xxxbb| 成人国产麻豆网| 好男人在线观看高清免费视频| 中文在线观看免费www的网站| 成人亚洲欧美一区二区av| 一级毛片 在线播放| 人妻少妇偷人精品九色| 在线精品无人区一区二区三 | 少妇的逼好多水| 色视频www国产| 亚洲成色77777| 爱豆传媒免费全集在线观看| 久久久久性生活片| 伦理电影大哥的女人| 亚洲av男天堂| 久久久久精品性色| 欧美潮喷喷水| 日本与韩国留学比较| 免费大片18禁| 国产亚洲av片在线观看秒播厂| 中文字幕av成人在线电影| 亚洲,一卡二卡三卡| 乱码一卡2卡4卡精品| 永久免费av网站大全| av一本久久久久| 国产精品99久久99久久久不卡 | 汤姆久久久久久久影院中文字幕| 亚洲欧美清纯卡通| 久久精品国产亚洲av涩爱| 国产成人91sexporn| 国产黄色视频一区二区在线观看| 人妻制服诱惑在线中文字幕| 亚洲精品国产成人久久av| 国产综合懂色| 国产黄片美女视频| 亚洲精品国产色婷婷电影| 成年av动漫网址| 人妻夜夜爽99麻豆av| 国产精品女同一区二区软件| 欧美97在线视频| 久久99蜜桃精品久久| 亚洲高清免费不卡视频| 国产毛片在线视频| 九色成人免费人妻av| 亚洲av不卡在线观看| 大话2 男鬼变身卡| 王馨瑶露胸无遮挡在线观看| 在线播放无遮挡| 少妇人妻久久综合中文| 又爽又黄无遮挡网站| 你懂的网址亚洲精品在线观看| 国产高清国产精品国产三级 | 成人亚洲精品一区在线观看 | 亚洲av一区综合| 97在线人人人人妻| 国产午夜精品久久久久久一区二区三区| 能在线免费看毛片的网站| 97超碰精品成人国产| 日韩制服骚丝袜av| 秋霞在线观看毛片| 国产精品一区二区性色av| 日韩成人av中文字幕在线观看| 男女那种视频在线观看| 看非洲黑人一级黄片| 国产 精品1| 亚洲av二区三区四区| 久久久精品94久久精品| 乱码一卡2卡4卡精品| 亚洲精品,欧美精品| 亚洲va在线va天堂va国产| 91狼人影院| 精品午夜福利在线看| 女人被狂操c到高潮| 免费观看av网站的网址| 性插视频无遮挡在线免费观看| 国产一区有黄有色的免费视频| 国产精品无大码| 亚洲av免费高清在线观看| 高清视频免费观看一区二区| 精品午夜福利在线看| 亚洲精品中文字幕在线视频 | 国产探花在线观看一区二区| 一级毛片 在线播放| 免费看av在线观看网站| 午夜日本视频在线| av.在线天堂| 深爱激情五月婷婷| 欧美变态另类bdsm刘玥| 777米奇影视久久| 极品教师在线视频| 亚洲精品久久久久久婷婷小说| 亚洲国产最新在线播放| 搞女人的毛片| 国产精品爽爽va在线观看网站| 欧美极品一区二区三区四区| 国产真实伦视频高清在线观看| 精品一区二区三区视频在线| 99精国产麻豆久久婷婷| 色播亚洲综合网| 97超碰精品成人国产| 亚洲精品色激情综合| 如何舔出高潮| 久久99精品国语久久久| 最近的中文字幕免费完整| 在线a可以看的网站| 久久久精品94久久精品| 国产淫语在线视频| av又黄又爽大尺度在线免费看| 免费看日本二区| 亚洲av欧美aⅴ国产| 国产av国产精品国产| 国产午夜精品一二区理论片| 又粗又硬又长又爽又黄的视频| 九九爱精品视频在线观看| 永久免费av网站大全| 91精品伊人久久大香线蕉| 一级爰片在线观看| 精品久久久久久电影网| 免费看av在线观看网站| 日日啪夜夜撸| 日韩 亚洲 欧美在线| 国产有黄有色有爽视频| 国产免费视频播放在线视频| 天天一区二区日本电影三级| 深爱激情五月婷婷| 欧美日本视频| 男女国产视频网站| 可以在线观看毛片的网站| 九九久久精品国产亚洲av麻豆| 女人被狂操c到高潮| 成人毛片60女人毛片免费| 天美传媒精品一区二区| 亚洲性久久影院| 日本猛色少妇xxxxx猛交久久| 老师上课跳d突然被开到最大视频| 亚洲成人中文字幕在线播放| 久久精品久久久久久久性| 国内少妇人妻偷人精品xxx网站| 亚洲va在线va天堂va国产| www.av在线官网国产| 国产精品爽爽va在线观看网站| 日韩视频在线欧美| 爱豆传媒免费全集在线观看| 老师上课跳d突然被开到最大视频| 美女主播在线视频| 晚上一个人看的免费电影| 男人舔奶头视频| 五月天丁香电影| 99视频精品全部免费 在线| 日日摸夜夜添夜夜爱| 国产成人午夜福利电影在线观看| a级毛片免费高清观看在线播放| 精品久久久噜噜| 日日撸夜夜添| 亚洲av在线观看美女高潮| 哪个播放器可以免费观看大片| 久久精品国产亚洲网站| 国产精品国产三级专区第一集| 久久久久精品性色| 成人毛片a级毛片在线播放| 婷婷色综合www| 三级经典国产精品| 卡戴珊不雅视频在线播放| 亚洲,欧美,日韩| 久久ye,这里只有精品| 一级毛片aaaaaa免费看小| 一本—道久久a久久精品蜜桃钙片 精品乱码久久久久久99久播 | 国产精品国产三级专区第一集| 亚洲欧美中文字幕日韩二区| 三级国产精品欧美在线观看| 国产老妇伦熟女老妇高清| 九九在线视频观看精品| 最近手机中文字幕大全| 欧美三级亚洲精品| 大香蕉97超碰在线| 国产成人精品久久久久久| 亚洲va在线va天堂va国产| 国产精品一区二区在线观看99| 色视频在线一区二区三区| 亚洲无线观看免费| 一级毛片久久久久久久久女| 伦精品一区二区三区| 嫩草影院精品99| 可以在线观看毛片的网站| 亚洲av福利一区| 亚洲人成网站高清观看| 中文精品一卡2卡3卡4更新| 国产 一区 欧美 日韩| 最新中文字幕久久久久| 久久精品夜色国产| .国产精品久久| 国产一区二区三区av在线| 久久国产乱子免费精品| 五月天丁香电影| 黄色日韩在线| 天美传媒精品一区二区| 欧美一级a爱片免费观看看| 日本wwww免费看| 日韩一区二区三区影片| 欧美日韩综合久久久久久| 国产精品女同一区二区软件| 成人综合一区亚洲| 欧美bdsm另类| 久久精品久久久久久久性| 久久精品人妻少妇| 一区二区三区免费毛片| 国产精品99久久久久久久久| 精品久久久久久电影网| 免费黄色在线免费观看| av福利片在线观看| 久久久国产一区二区| 亚洲精品中文字幕在线视频 | 26uuu在线亚洲综合色| 麻豆成人午夜福利视频| 欧美激情久久久久久爽电影| 啦啦啦在线观看免费高清www| 国产精品久久久久久久久免| av在线蜜桃| 一区二区三区四区激情视频| 免费人成在线观看视频色| 久久精品久久久久久噜噜老黄| 久久精品夜色国产| 欧美区成人在线视频| 欧美日韩视频高清一区二区三区二| av在线app专区| 中文欧美无线码| 男人爽女人下面视频在线观看| 十八禁网站网址无遮挡 | av一本久久久久| 久久久欧美国产精品| 狂野欧美激情性xxxx在线观看| 亚洲精华国产精华液的使用体验| 日韩成人av中文字幕在线观看| 不卡视频在线观看欧美| 嫩草影院入口| 亚洲第一区二区三区不卡| 2021少妇久久久久久久久久久| 永久网站在线| 亚洲欧美中文字幕日韩二区| 日产精品乱码卡一卡2卡三| 成年免费大片在线观看| 免费观看a级毛片全部| 久热久热在线精品观看| 日韩中字成人| 中文字幕人妻熟人妻熟丝袜美| 99热网站在线观看| 黄色欧美视频在线观看| 国产亚洲最大av| 色5月婷婷丁香| 观看美女的网站| 精品少妇黑人巨大在线播放| 嫩草影院入口| 亚洲欧美一区二区三区黑人 | 国产亚洲精品久久久com| 国产精品一区二区性色av| 国产精品一区www在线观看| 91午夜精品亚洲一区二区三区| 午夜福利视频精品| 国产成人freesex在线| 欧美zozozo另类| 久久久久久久久久久免费av| 国产亚洲精品久久久com| 国产高潮美女av| 午夜激情福利司机影院| av免费观看日本| 亚洲精品乱码久久久v下载方式| 久久久久久伊人网av| 国产日韩欧美在线精品| 日韩强制内射视频| 免费大片黄手机在线观看| 亚洲精品影视一区二区三区av| 欧美区成人在线视频| 久久久色成人| 午夜日本视频在线| 欧美日韩亚洲高清精品| 一级毛片 在线播放| 成人综合一区亚洲| 欧美性猛交╳xxx乱大交人| 十八禁网站网址无遮挡 | 嫩草影院新地址| 精品酒店卫生间| 国语对白做爰xxxⅹ性视频网站| 国产精品一区二区性色av| 欧美xxxx性猛交bbbb| 国产午夜精品久久久久久一区二区三区| 国产精品蜜桃在线观看| 国产成人免费观看mmmm| 日韩电影二区| 深爱激情五月婷婷| 波野结衣二区三区在线| 日韩亚洲欧美综合| 2021天堂中文幕一二区在线观| 国产欧美日韩一区二区三区在线 | 97超碰精品成人国产| 天美传媒精品一区二区| 91久久精品国产一区二区成人| h日本视频在线播放| 一区二区三区乱码不卡18| 国产免费一级a男人的天堂| 欧美xxxx性猛交bbbb| 深夜a级毛片| 欧美高清性xxxxhd video| 高清日韩中文字幕在线| 小蜜桃在线观看免费完整版高清| 嫩草影院精品99| 国产精品一区二区三区四区免费观看| 久久国内精品自在自线图片| 亚洲精品久久久久久婷婷小说| 久久久久久久大尺度免费视频| 七月丁香在线播放| 赤兔流量卡办理| 午夜免费鲁丝| 九九在线视频观看精品| 免费黄色在线免费观看| 国内揄拍国产精品人妻在线| 大又大粗又爽又黄少妇毛片口| 国产精品精品国产色婷婷| 国产精品.久久久| 亚洲欧美清纯卡通| 国产极品天堂在线| 亚洲美女搞黄在线观看| 国产成人福利小说| 国产一区二区三区综合在线观看 | 国产精品麻豆人妻色哟哟久久| 欧美国产精品一级二级三级 | 18+在线观看网站| 亚洲色图综合在线观看| 成年女人看的毛片在线观看| 日韩一区二区三区影片| 菩萨蛮人人尽说江南好唐韦庄| 亚洲三级黄色毛片| 青青草视频在线视频观看| 一个人看的www免费观看视频| 好男人在线观看高清免费视频| 一区二区三区精品91| 别揉我奶头 嗯啊视频| 国产av不卡久久| 在线精品无人区一区二区三 | 久久久久久久亚洲中文字幕| 99九九线精品视频在线观看视频| 成人亚洲欧美一区二区av| 精品人妻熟女av久视频| 少妇丰满av| 精品一区二区三卡| 精品少妇久久久久久888优播| 国产有黄有色有爽视频| a级毛色黄片| www.色视频.com| 久热这里只有精品99| 女人十人毛片免费观看3o分钟| 午夜福利在线观看免费完整高清在| 午夜激情福利司机影院| 菩萨蛮人人尽说江南好唐韦庄| a级一级毛片免费在线观看| 亚洲欧美日韩卡通动漫| 在线看a的网站| 干丝袜人妻中文字幕| 色吧在线观看| 亚洲人成网站在线观看播放| av卡一久久| av.在线天堂| 国产亚洲一区二区精品| 一本—道久久a久久精品蜜桃钙片 精品乱码久久久久久99久播 | 菩萨蛮人人尽说江南好唐韦庄| 久久这里有精品视频免费| 女人十人毛片免费观看3o分钟| 在线看a的网站| 嘟嘟电影网在线观看| 亚洲自偷自拍三级| 不卡视频在线观看欧美| 国产老妇伦熟女老妇高清| 哪个播放器可以免费观看大片| 99热这里只有是精品50| 嫩草影院新地址| 大话2 男鬼变身卡| 特大巨黑吊av在线直播| 国产av不卡久久| 免费大片黄手机在线观看| 在线 av 中文字幕| 欧美日韩精品成人综合77777| 欧美一级a爱片免费观看看| 久久久久久久精品精品| 制服丝袜香蕉在线| 特大巨黑吊av在线直播| 一级a做视频免费观看| 久久鲁丝午夜福利片| 国产淫片久久久久久久久| 成人黄色视频免费在线看| 精品久久久噜噜| 啦啦啦中文免费视频观看日本| 我的老师免费观看完整版| 亚洲精品456在线播放app| 久久人人爽人人爽人人片va| 99久久九九国产精品国产免费| 亚洲成人久久爱视频| 国产精品秋霞免费鲁丝片| 亚洲人成网站在线观看播放| 亚洲国产最新在线播放| 亚洲欧美精品专区久久| 精品久久久噜噜| 国产av国产精品国产| 久久久久久九九精品二区国产| 九九爱精品视频在线观看| 九色成人免费人妻av| 看十八女毛片水多多多| 亚洲精品成人av观看孕妇| 一级毛片 在线播放| 欧美+日韩+精品| 大片免费播放器 马上看| 一级毛片黄色毛片免费观看视频| 久久久色成人| 国产一区二区三区综合在线观看 | 九九爱精品视频在线观看| 少妇丰满av| 久久久久久久久久久丰满| 高清日韩中文字幕在线| 亚洲三级黄色毛片| 国产亚洲最大av| 搞女人的毛片| 大片免费播放器 马上看| 精品熟女少妇av免费看| 精品人妻熟女av久视频| 街头女战士在线观看网站| 国产欧美日韩一区二区三区在线 | av国产久精品久网站免费入址| 精品熟女少妇av免费看| 日韩 亚洲 欧美在线| 日韩欧美精品v在线| 国产在线一区二区三区精| 又粗又硬又长又爽又黄的视频| 18+在线观看网站| 国精品久久久久久国模美| 一级毛片黄色毛片免费观看视频| 午夜爱爱视频在线播放| 午夜福利在线在线| 午夜精品国产一区二区电影 | 亚洲国产色片| 亚洲成人精品中文字幕电影| 夜夜爽夜夜爽视频| 一个人观看的视频www高清免费观看| 亚洲av中文av极速乱| 国产高清三级在线| 丝袜美腿在线中文| 欧美亚洲 丝袜 人妻 在线| 国产成人a区在线观看| 亚洲国产精品成人综合色| 日日啪夜夜撸| 午夜精品一区二区三区免费看| 天天躁日日操中文字幕| 国产午夜精品久久久久久一区二区三区| 联通29元200g的流量卡| 一区二区三区免费毛片| 亚洲天堂av无毛| 少妇的逼水好多| 国内精品宾馆在线| 国产精品av视频在线免费观看| 人妻一区二区av| 精品人妻熟女av久视频| 亚洲一级一片aⅴ在线观看| 大香蕉久久网| 麻豆乱淫一区二区| 国产av不卡久久| 精品国产露脸久久av麻豆|