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RADAR, OPTICAL AND SATELLITE STUDIES OFCLIMATOLOGY AND EFFECTS OF ATMOSPHERIC GRAVITYWAVES AND TURBULENCENikolai M. GavrilovAtmospheric Physics Department, Saint-Petersburg State University, Petrodvorets, St.Petersburg, 198504, Russia, gavrilov@pobox.spbu.ruAbstract. Some results of studies of climatology of internal gravity waves (IGWs) in themiddle and upper atmosphere are presented. MST and MF radars give information aboutseasonal and interannual changes of the mean winds and IGW variances. Low-orbitsatellites receiving GPS signals may give distribution of zones of increased IGW andturbulence intensity and of wave generation. Multi-beam MST radar observations giveinformation about mesoscale nonlinear IGW sources in the tropo-stratosphere. Numericalmodels allow to study sensitivity of general circulation of the middle atmosphere toglobal inhomogeneity of IGW sources observed with radars and GPS satellites.1. IntroductionFor better understanding and interpreting, MST radars studies should be completed byother observations with various ground-based and satellite techniques and by theoreticalstudies. In this paper, we present a short review of some recent studies of climatology ofinternal gravity waves (IGWs) in Saint-Petersburg University (Russia). These studiesinclude an analysis of seasonal and interannual variations of wind velocity in the middleatmosphere with MST and medium frequency (MF) radars, optical observations of shortperiodvariations of night airglows, analysis of global structure of IGWs and their sourcesin the lower and middle atmosphere from the data of low-orbit GPS satellites. Numericalmodeling of IGW spectrum propagation in the atmosphere and study of sensitivity of anumerical model of general circulation of the middle atmosphere to observed horizontalinhomogeneity of IGW distribution at low boundary are discussed.2. Analysis of radar data.In the last years, a considerable progress has been achieved in studies of IGWclimatology with radar technique in the atmosphere. A group of Saint-PetersburgUniversity participated in joint analyses of the data from Saskatoon medium frequency(MF) radar [Gavrilov et al., 1995], from Japanese MU radar [Gavrilov et al., 2000], frommulti-year D1 observations of ionospheric drifts at Collm Observatory, Germany[Gavrilov et al., 2001], and from other meteor and MF radars. Recently, an analysis ofseasonal and interannual variations of IGW characteristics at altitudes of 70 – 90 km overHawaii (22° N, 159° W) from the data of MF radar was made [Gavrilov et al., 2003a,b].Hawaii MF radar gives the wind velocity values with time step of about 2 min andheight resolution of 2 km. For each altitude, we obtain hourly mean values of zonal andmeridional wind velocity components and their hourly variances. The latter giveinformation about wind perturbations with time scales up to 1 hr, which are called as"within hour" (WH) data. Differences of consecutive hourly data give information aboutperturbations with periods 1 – 5 hr (HD data). Transmission functions of these numericalfilters are described by Gavrilov et al. [2003a]. After calculating hourly-mean velocitiesand WH and HD perturbations, we calculate monthly mean values taking account ofnumbers, n i , of good velocity measurements during each hour. Obtained monthly meanwinds and variances we use in this paper for the study of seasonal changes of the mean168
winds and variances at altitudes 70 - 90 km. To increase statistical reliability, we use onlyhours with n i >N, where N may vary in different kinds of analysis.This method is applied for the analysis of measurements with MF radar at Hawaii (22°N, 159° W) during years 1990 - 2000. Figure 1 represents interannual variations of themean wind components. Below altitudes 82 - 85 km, zonal wind has mainly annualvariation with the maxima of eastward wind in winter and of westward wind in summer.Above 82 - 85 km, there is a semiannual variation of the mean zonal wind with additionalmaximum of eastward wind in summer. Seasonal variations of the mean meridional windin Figure 1 are more complicated and seem to be a superposition of annual andsemiannual harmonics with their phases variable in height.Figures 2 and 3 show interannual variations of WH and HD wind variancesrepresenting, probably, the intensity of IGWs with periods 0.1 - 1 hr and 1 - 5 hr,respectively. One can see clear seasonal variations of the variances with the mainmaximum in winter and a secondary maximum in summer below altitudes 82 - 85 km,which are more noticeable in Figure 2 for WH component. Above these altitudes, there isa tendency to equinox's maxima of IGW activity in Figures 2 and 3. [see Gavrilov et al.,2003a]. Considering absolute values of WH and HD variances in Figures 2 and 3, oneshould keep in mind that these values could be overestimated at lower heights, where wehave larger numbers of data gaps.One of possible reasons of wind variations at MLT could be heating and cooling ofPacific surface water known as the El Nino and La Nina events, respectively. Anindicator of El Nino effects in the atmosphere is the Southern Oscillation Index (SOI)reflecting the surface pressure difference between tropical observation points Tahiti andDarwin. Positive SOI values correspond to La Nina and negative SOI – to El Nino events.Mean Winds over HawaiiHourly N > 8Z,km9070Zonal Wind, m/s25155-5-15-25-35-45Z,km9070Meridional Wind, m/s1990 1995 2000Years840-4-8-12-16-20Fig. 1. Height-Interannual variations of the mean wind components over Hawaii.169
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MST10Tenth InternationalWORKSHOPOn
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MST 10 Group PictureMay 15 th , 200
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TENTH INTERNATIONAL WORKSHOP ON TEC
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Table of ContentsPREFACE ..........
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I.2.18 FURTHER OBSERVATIONS OF PMSE
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I.3.27 NEW MST RADAR METHODS FOR ME
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I.4.19 STUDY OF A MESOSCALE LAND-TO
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I.5.502 AN ATTEMPT TO CALIBRATE THE
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PrefaceMST10The Tenth International
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and the local organizing committee,
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The operational aspects and recent
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To improve the understanding of dyn
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Improving MST radar resolution by u
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latitudes, arguing that the former
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Report on Session I.3 “Winds, Wav
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Turbulence.The session then moved i
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Report on Session I.4 “Meteorolog
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Multiple Antenna Profiling Radar (M
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Report on Session II “Novel Persp
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synchronized by GPS and connected v
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The highly positive response of the
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10th International Workshop on Tech
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10th International Workshop on Tech
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Session I.1: Radar scattering proce
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⎡7800 ∂q⎤(3)⎢ 15500q⎥M =
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Figure 2 compares profiles of ω B
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Figure 1: Data from the MST radar a
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Ri =shear2ωB22⎛ ∂u⎞ ⎛ ∂v
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Meridional (deg)1050−5−10Echo P
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Subarray Configuration, Capon Metho
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Fig. 2 PMSE plot (SOUSY Svalbard Ra
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VHF radar interferometry had shown
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turbulence. From Figures 1 and 2, i
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SummaryFrom the aspect sensitivity
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a specific range. In this work, syn
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P C(dB)(a) Echo Power60504030200.70
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most occidental area of South Ameri
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Quegan, 1992). It should be useful
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measurements, is shown in figure 1(
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The present observations thus empha
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RECENT OBSERVATIONS OF E REGION FIE
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measured spectra in order to separa
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drifts at E and F regions heights b
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• Are characterized by type II ec
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The main parameters that could be o
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THE ROLE OF UNSTABLE SPORADIC-E LAY
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(σ H / σ P )E y (where σ H and
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STUDY OF A LOW E-REGION QUASI-PERIO
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100 m/syrFigure 4: Geometry of the
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Where the notations carry same mean
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Where dx/dt and dy/dt are the veloc
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non-negativity of the image is prio
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spectrum corresponding to the backs
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The Artigas and Machu-Picchu Statio
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Arguments against the second altern
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Extension of the Kolmogorov spectru
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volumeESRvolumeSSRSSR SSRESR ESRSSR
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individual particles in a statistic
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Anomalous spectraTalkner [4] studie
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To observe the E region FAI echoes,
Page 123 and 124: matter daytime or nighttime and are
Page 125 and 126: two sub-arrays, each sub-array made
Page 127 and 128: 4. SummaryHere we describe a radio
Page 129 and 130: Figure 1. E-region DPS4 spectra, ri
Page 131 and 132: effects. It is therefore plausible
Page 133 and 134: 1996 and high in 2002). The electri
Page 135 and 136: electric fields map along the geoma
Page 137 and 138: SNR condition is always difficult a
Page 139 and 140: Figure-4 Power spectrum plots of a
Page 141 and 142: As we show below, Jicamarca offers
Page 143 and 144: particularly during daytime counter
Page 145 and 146: where ˆδ nm = (δ l − δ m )
Page 147 and 148: PMSE is more easily interpreted as
Page 149 and 150: ResultsTemperature climatology• s
Page 151 and 152: Simultaneous PMSE and NLC observati
Page 153 and 154: ResultsSeasonal variationMSE are no
Page 155 and 156: Figure 2: MSE parameters as functio
Page 157 and 158: Session I.3: Winds, waves and turbu
Page 159 and 160: poor. It was shown that poor perfor
Page 161 and 162: The use of diffraction pattern simi
Page 163 and 164: F 13 (ξ x ′) = (1 − cos 2ψ N)
Page 165 and 166: Figure 3: (a) Baseline length depen
Page 167 and 168: 3. ResultsFigure 1 shows the amplit
Page 169 and 170: variability.Figure 4 shows the aver
Page 171 and 172: Figure 1. Period-time amplitude wav
Page 173: the 12-h and 24-h periodicities in
Page 177 and 178: similar correlation with larger mag
Page 179 and 180: of the refraction index are not equ
Page 181 and 182: Fig. 8. Zonal wind (top) and temper
Page 183 and 184: STUDIES ON ATMOSPHERIC GRAVITY WAVE
Page 185 and 186: 1100-1200 hours. From this plot 6.3
Page 187 and 188: STUDIES ON WINDS AND MOMENTUM FLUXE
Page 189 and 190: 3.4 Monthly variation of momentum f
Page 191 and 192: DEEP PENETRATIVE CONVECTION AND GEN
Page 193 and 194: ly changes direction with time with
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Page 197 and 198: 191
Page 199 and 200: 193
Page 201 and 202: These two last relations are the on
Page 203 and 204: 3.2.1 From v ′2 to ɛ kThe questi
Page 205 and 206: 5.2 Frequency distributionsSeveral
Page 207 and 208: ReferencesAlisse J.-R. and C. Sidi.
Page 209 and 210: Röttger J. and C.H. Liu. Partial r
Page 211 and 212: Specular reflection is negligible f
Page 213 and 214: −0.5C n2 Distribution (PROUST & S
Page 215 and 216: the beamwidth, α is the zenith ang
Page 217 and 218: this latitude in late April). Surfa
Page 219 and 220: Fig. 1. Median (upper) winds and (l
Page 221 and 222: Fig.1. Lines of constant radial vel
Page 223 and 224: which have not yet been considered
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is calculated from the radiosonde t
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Figure 3: Time-altitude cross-secti
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Absorption of cosmic noise is cause
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Incoherent scatter spectracompared
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variations of spectral widths, refr
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Figure 1. Diurnal variation of Turb
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further experimental test of the ST
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waves can be observed more clearly
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winter and a minimum in summer near
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The main recently assumed mechanism
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Figure 2. Statistics of numbers of
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LIDAR OBSERVATIONS OF MIDDLE ATMOSP
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latitudinal dependence of the seaso
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APPLICATION OF THE DUAL-BEAMWIDTH M
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Figure 2: Mean zonal and meridional
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JLKLLK/ILIL6II/G/II/G/LEODFLK/LO/DD
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The monthly diurnal mean of horizon
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Session I.4: Meteorological Phenome
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Integration of the VHF wind profile
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Figure 1 : Map of the Lago Maggiore
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precipitating clouds, the cyclonic
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Eyewall(a)(b)(c)(d)Fig. 3: Radius-h
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as low as 0.55. The Piura 50-MHz ra
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place features in the profile with
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• Period 1 (June 1-10): SCCs exis
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Sumatera occurs by stratiform cloud
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very interesting to note the double
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20(a) Convective Region(b) Transiti
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Typhoon LekimaFig. 2 Typhoon Lekima
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Fig. 5 Passage of typhoon Hayan on
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the 50 cm 2 sensor head, enabling t
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22 June 2000 23:22:23 - 23:24:20 at
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the time-height section of a convec
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Thurai, M., T.Iguchi,T. Kozu, J.D.E
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There are two main mechanisms which
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Horel, J.D. and Cornejo-Garrido, A.
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estimating two independent and redu
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RASS THETA (K) RASS v-component (m/
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Surface winds usually range from 10
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weak (maximum of 5 m s -1 ) and the
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The vertical component from the VTB
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Figure 8 shows the profile of virtu
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2 3D ( , ) ( ) ( ) ˆ ( ) ˆp∆ xm
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presented in Praskovsky et al. (200
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In Fig. 2 a sketch of a mountain le
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In Fig. 8 the lamina is aligned on
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Figure 1: composite day (13 days) o
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virtual sensible heat fluxes ( Wm-2
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3. Characteristics of precipitation
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Fig. 3: Horizontal distribution of
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3. Results and discussionUHF profil
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Figure 4. Monthly variation of slop
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system with two receiving antennae,
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cycle of precipitation. Figure 3(a)
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Histogram of Zonal Velocityh=5.13 K
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5. Summary of results and concludin
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the two nearby major cities, Chenna
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Boundary layer height, km32.521.5(a
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Figure 1:Data from the MST radar at
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spectral processing. In this partic
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3. Results and discussionIn the pre
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4. SummaryAn attempt has been made
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The purpose of this study is to exa
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Figure1. Three-day average of momen
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3. The improved method to estimate
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But in case of period until 1800 UT
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Session I.5: Operational Aspects an
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The profilers of WINDAS weredesigne
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NOAA, 1994 : Wind profiler assessme
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FIRST RESULTS OF THE BOUNDARY LAYER
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Figure 3. Pulse Design Diagram to s
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MOVEABLE UHF/S-BAND PROFILER/DISDRO
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one-minute Z values determined from
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TOWARD A MULTISENSOR GROUND BASED R
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3. Cloud Evolution Case StudyOn the
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DEVELOPMENT OF A DIGITAL RECEIVER F
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Experiment 1 Experiment 2IPP 999Km
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ELECTRONIC DIGITAL BEAMFORMING IMPL
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The main element of the unit (figur
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.ON-LINE ADAPTIVE DC-GROUND-CLUTTER
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esulting in a widening of the bandw
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ON THE RADIATION EFFICIENCY OF COCO
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Table 2: Experiment #1 results, Tra
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A NEW NARROW BEAM MF RADAR AT 3 MHZ
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Off-zenith beams towards N, S, E, W
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95ALWIN VHF radar: signal powerdB80
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ANTENNA BEAM VERIFICATION USING COS
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Figure 2: A 45 MHz reference sky te
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AN ATTEMPT TO CALIBRATE THE UHF STR
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is at 4.7 km, but in the first 4-ga
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QUALITY CONTROL FOR DOPPLER WIND PR
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The resulting moments are subjected
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SOUSY RADAR AT JICAMARCA: SYSTEM DE
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NEControl andcomputer roomCompCoute
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THE EQUATORIAL ATMOSPHERE RADAR:SYS
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Table 1: Specifications of the EAR
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VHF ATMOSPHERIC AND METEOR RADAR IN
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ased upon a geotechnical engineerin
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VORTICAL MOTIONS OBSERVED WITH THE
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interpolation from the original gri
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A NEW MINIRADAR TO INVESTIGATE URBA
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e eliminated to analyze correctly t
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Session PWG 1: System Calibrations
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Session PWG 2: Data Analysis, Valid
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• the time series vectors x(k) of
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Fig. 4: reflectivity of the hydrome
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Session PWG 3: Accuracies and Requi
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Session PWG 4: International Collab
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Session II.E: NOVEL PERSPECTIVES AN
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2 Proposed AlgorithmReceived signal
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N#4E-1-16E1A1#1#2A-1-1C1#3C-1-19Fig
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of conventional DCMP, with which th
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applying the directional constraint
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while for a beam of finite width, t
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In order to make the process more q
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WHAT IS TURBULENCE SEEN BY VHF RADA
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Enhanced resolution applyingpulse s
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Beckmann, Spizichino, 1964Fig. 8 Po
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Fig. 11 Plots of temporal variation
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Fig. 14 Distributions of phase cent
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Hocking, W.K., Radar studies of sma
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THE STRUCTURE FUNCTION-BASED APPROA
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{ Ui( t), Vi( t), Wi( t)} = { Ui ,
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161). Assumption 2H: the instantane
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Only the second order SF are consid
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fluctuations umk( t ) along the bas
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VHF PARASITIC RADAR INTERFEROMETRYF
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• All the costs of transmitter pr
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Figure 2: Example of range-azimuth
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Target Altitude, km1009080706050403
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ReferencesGriffiths, H. D., A. J. G
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Participants ListAvery, James P.Uni
Page 489 and 490:
Hysell, David L.EAS/Cornell Univers
Page 491 and 492:
Silva, Robert R.ATRADAustraliarsilv
Page 493 and 494:
AAdachi, A. .......................
Page 495:
TTabary, P. .......................
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