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RESULTS OF SEVERAL YEARS MSE OBSERVATION ATKÜHLUNGSBORN (54°N)Marius Zecha, Jürgen Bremer, and Peter HoffmannLeibniz-Institut für Atmosphärenphysik and der Universität RostockD-18225 Kühlungsborn, GermanyIntroductionVery strong echoes from upper mesospheric heights in polar regions are observed by VHFradars for several years. The radar waves are backscattered by irregularities of the refractionindex of half the radar wavelength mainly caused by electron density fluctuations. Such smallirregularities should normally be destroyed at mesospheric heights by viscous forces.Therefore, it is commonly accepted that charged aerosols or ice particles prevent thedestruction of these irregularities by an effective reduction of the electron diffusivity (Cho etal., 1992, Rapp and Lübken, 2003). The good correlation between PMSE and noctilucentclouds (NLC) as found in simultaneous and common volume observations (von Zahn andBremer, 1999) confirm the existence of ice particles during PMSE.Mesosphere summer echoes (MSE) at mid-latitudes are a rare phenomenon in contrast to thecorresponding polar mesosphere summer echoes (PMSE) at arctic latitudes (Bremer et al.,2003, Zecha et al., 2003). Studies of MSE characteristics are therefore more seldom thanstudies of PMSE. Nearly continuous measurements at Kühlungsborn during the summers1998 and 2000 to 2002 gave the chance to study the main properties of MSE on goodstatistical conditions.ExperimentThe MSE observations were performed with the 53.5 MHz VHF radar system at Kühlungsborn(54.1°N, 11.8°E) near the Baltic Sea.The essential radar parameters used for mesospheric measurements are listed in the followingtable:operating frequency53.5 MHzpeak power36 (72) kWduty cycle 5%transmitting antenna144 Yagi arrayeff. Antenna area1900 m2receiving antennaarray divisible in 6 subarray a 24 Yagihalf-power beam width 6.0°pulse repetition frequency 1500 Hzpulse length 2 µscode (complementary) 16 bitsampling resolution300 mlength of time series~20 sec146
ResultsSeasonal variationMSE are normally observed at Kühlungsborn between the beginning of June and the middleof August as tagged by the vertical dashed lines in the upper panel of figure 1a. The meandaily occurrence rates show strong day-to-day variations with values between 0% and 18%(black bars). The blue dashed curve has been estimated by a polynomial fit through the dailyvalues. The mean occurrence rate of noctilucent clouds at mid-latitudes is markedly smallerthan the occurrence rate of MSE. No more than three events per year have been observed.Furthermore the NLC period characterized by the green horizontal line is limited to the firsthalf of the MSE period only.As demonstrated in the lower panel of the figure the degree of saturation S (derived fromsmoothed and interpolated Kühlungsborn lidar temperature data and a water vapor mixingratio estimated from model calculations) is in general smaller than 1. Therefore, the conditionS>1 as necessary for the existence of ice particles in the mesosphere could only be fulfilledduring gravity wave induced temperature minima.Diurnal variationIn figure 1b the mean diurnal variation of the occurrence rate of MSE is separately shown forthe four years of observation (black curves with dots). Normally MSE are observed onlyduring daytime with a maximum near noon. The diurnal variation of electron density is alsoshown (solid red curves) for an altitude of 85 km at mid-latitudes after the IRI-95 model(http://nssdc.gsfc.nasa.gov/space/model/models/iri.html). The comparison of the MSEoccurrence rates with the electron densities leads to the conclusion that MSE can only beobserved if the electron density is above about 500 el./cm 3 .Fig. 1a: Seasonal variation of MSEFig. 1b: Diurnal variation of MSE147
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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
Page 101 and 102: Where the notations carry same mean
Page 103 and 104: Where dx/dt and dy/dt are the veloc
Page 105 and 106: non-negativity of the image is prio
Page 107 and 108: spectrum corresponding to the backs
Page 109 and 110: The Artigas and Machu-Picchu Statio
Page 111 and 112: Arguments against the second altern
Page 113 and 114: Extension of the Kolmogorov spectru
Page 115 and 116: volumeESRvolumeSSRSSR SSRESR ESRSSR
Page 117 and 118: individual particles in a statistic
Page 119 and 120: Anomalous spectraTalkner [4] studie
Page 121 and 122: 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: Simultaneous PMSE and NLC observati
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 and 174: the 12-h and 24-h periodicities in
Page 175 and 176: winds and variances at altitudes 70
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
Page 195 and 196: 189
Page 197 and 198: 191
Page 199 and 200: 193
Page 201 and 202: These two last relations are the on
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3.2.1 From v ′2 to ɛ kThe questi
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5.2 Frequency distributionsSeveral
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ReferencesAlisse J.-R. and C. Sidi.
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Röttger J. and C.H. Liu. Partial r
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Specular reflection is negligible f
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−0.5C n2 Distribution (PROUST & S
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the beamwidth, α is the zenith ang
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this latitude in late April). Surfa
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Fig. 1. Median (upper) winds and (l
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Fig.1. Lines of constant radial vel
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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
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Hysell, David L.EAS/Cornell Univers
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Silva, Robert R.ATRADAustraliarsilv
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AAdachi, A. .......................
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TTabary, P. .......................
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