Proceedings with Extended Abstracts (single PDF file) - Radio ...

More documents

Recommendations

Info

MULTITAPER SPECTRAL ANALYSIS OF ATMOSPHERIC RADARSIGNALSV.K.Anandan (1)* , T. Rajalakshmi (2) , G. Ramachandra Reddy (2) , C.J.Pan (1)(1) Institute of Space Science, National Central University, Chung-Li, 32054, TaiwanEmail: anandanvk@hotmail.com*On leave from National MST Radar Facility, Gadanki, India(2) Department of EEE, SV University, Tirupati, AP, India, 517 502AbstractMultitaper spectral analysis using sinusoidal tapers has been carried out on backscatteredsignals received from the troposphere and lower stratosphere by the Gadankimesosphere-stratosphere-troposphere (MST) radar under various conditions. The sine tapershave much narrower main lobe and much higher side lobes. Thus they achieve a smaller biasdue to smoothing by the main lobe, but at the expense of side lobe suppression. The analysisis carried out on different data sets. Comparison of study is made with single taper tounderstand the relative merits of the processing under the scheme. The result shows thatmultitaper analysis gives better signal to noise ratio or higher detectability. The signals arebetter identified in the multitaper analysis in both sets of data. The spectral analysis throughmultitaper and single-taper is subjected to study of consistency in measurements. Resultshows that multitaper is having very low variance compared to single taper estimators.IntroductionTapering is another name for the data windowing operation in the time domain. Singletaper smoothed spectrum estimates are plagued by a trade-off between the variance of theestimate and the bias caused by spectral leakage [Park et al., 1987]. Applying a taper toreduce bias, discards data, increasing the variance of the estimate. Using a taper alsounevenly samples the record. Single-taper estimators, which are less affected by leakage, notonly have increased variance but also can misrepresent the spectra of non-stationary data. Soas long as only a single data taper is used, there will be a trade-off between the resistance tospectral leakage and the variance of a spectral estimate.Thomson [1982] introduced the multitaper spectral analysis technique and applicationfound in various scientific fields[Park et al., 1987]. First, the data are multiplied by not one,but several leakage-resistant tapers. This yields several tapered time series from one record.Taking the DFTs of each of these time series, several “eigen spectra” are produced whichare averaged to form a single spectral estimate. The central premise of this multitaperapproach is that if the data tapers are properly designed orthogonal functions, then, undermild conditions, the spectral estimates would be independent of each other at everyfrequency. Averaging would reduce the variance while proper design of full - length windowswould reduce bias and loss of resolution.Reidel and Siderenko [1995] proposed a set of orthonormal taper, which containharmonically related sinusoidal tapers. These tapers are called sinusoidal tapers or minimumbias tapers. The discrete analogs of the continuous time minimum bias tapers are calledsinusoidal tapers. The n th sinusoidal taper is given by2 ⎛ πkn⎞v k( n)= sin⎜⎟ ; n = 1,2,…,N ; k=1,2,…,K (1)N + 1 ⎝ N + 1⎠Identifying the signal and computing the three low order spectral moments is centralto the problem of extracting information from the Doppler spectrum of the Mesosphere-Stratosphere-Troposphere (MST) radar signal. The straightforward method of analyzing theMST radar spectral data is based on identifying the most prominent peak of the Dopplerspectrum for each range gate and computing the three low order spectral moments using theexpressions given by Woodman [1985]. Since MST radar signals are characterized by rapidlyfalling signal-to-noise ratio (SNR), the identification of atmospheric signals and in a weak130
SNR condition is always difficult and leading to erroneous estimation of moments. Todemonstrate the capability and advantageous of this method, analysis is carried out withmultitaper spectral estimate on MST radar signals.Observation and ResultsMST radar at Gadanki (13.5°N, 79.2°E) is operated on 11 April and 10 May 2002with 6 beam directions (Zenith-X, Zenith-Y in vertical and East, West, North, South directionwith 10 deg from vertical) in high-resolution mode to receive the atmospheric data. This datais subjected to the analysis based on multitaper and normal windowing (rectangular) spectralestimation. For multitaper spectral estimation 3 rd order taper is used, which is found to beoptimum in this case. After removing the noise [Hildebrand and Sekhon, 1974], the firstthree order moments are estimated from the spectrum using the expressions given byWoodman [1985].Figure 1a1 and 1a2 shows the power spectrum obtained using multi taper andrectangular window on 10 May 2002. This day, the radar echoes were reasonably strong andable to see the data up to 23 km in the case of multi taper spectral estimate and up to 22 Kmin the case of rectangular window method. Figure 1b1 and 1b2 shows the data on 11April2002, analyzed with the multi taper and rectangular window respectively. This day the radarechoes were very weak and trace is visible only up to 20 Km with intermittent breaks. In bothcases the multitaper based power spectrum is better visible. In multitaper spectrum the noisefluctuations are very less and the echoes are less compared to that of power spectrumobtained through rectangular window. This shows that multitaper spectral estimation isworking in a higher SNR regime and the signal detectability is improved by this method. Themethod is applied to data obtained through other beam directions also. Similar result isobserved in all cases.Figure 1 power spectrum obtained through (a1)Multitaper order-3, (a2) rectangular window on 10May2002, (b1) same as that of (a1) but on 11 April 2002, 9b2) same as that of (a2) but on 11April 2002The above data further analyzed to estimate the first three order moments such aspower (SNR), Doppler and Doppler width. Figure 2a1 and 2a2 shows the mean Dopplerobtained from the power spectrum for the west beam on 10 May with Multitaper andrectangular window respectively. The mean Doppler is obtained from 15 minutes observation131
Page 1 and 2:
MST10Tenth InternationalWORKSHOPOn
Page 3 and 4:
MST 10 Group PictureMay 15 th , 200
Page 5 and 6:
TENTH INTERNATIONAL WORKSHOP ON TEC
Page 7 and 8:
Table of ContentsPREFACE ..........
Page 9 and 10:
I.2.18 FURTHER OBSERVATIONS OF PMSE
Page 11 and 12:
I.3.27 NEW MST RADAR METHODS FOR ME
Page 13 and 14:
I.4.19 STUDY OF A MESOSCALE LAND-TO
Page 15 and 16:
I.5.502 AN ATTEMPT TO CALIBRATE THE
Page 17 and 18:
PrefaceMST10The Tenth International
Page 19 and 20:
and the local organizing committee,
Page 21 and 22:
The operational aspects and recent
Page 23 and 24:
To improve the understanding of dyn
Page 25 and 26:
Improving MST radar resolution by u
Page 27 and 28:
latitudes, arguing that the former
Page 29 and 30:
Report on Session I.3 “Winds, Wav
Page 31 and 32:
Turbulence.The session then moved i
Page 33 and 34:
Report on Session I.4 “Meteorolog
Page 35 and 36:
Multiple Antenna Profiling Radar (M
Page 37 and 38:
Report on Session II “Novel Persp
Page 39 and 40:
synchronized by GPS and connected v
Page 41 and 42:
The highly positive response of the
Page 43 and 44:
10th International Workshop on Tech
Page 45 and 46:
10th International Workshop on Tech
Page 47 and 48:
Session I.1: Radar scattering proce
Page 49 and 50:
⎡7800 ∂q⎤(3)⎢ 15500q⎥M =
Page 51 and 52:
Figure 2 compares profiles of ω B
Page 53 and 54:
Figure 1: Data from the MST radar a
Page 55 and 56:
Ri =shear2ωB22⎛ ∂u⎞ ⎛ ∂v
Page 57 and 58:
Meridional (deg)1050−5−10Echo P
Page 59 and 60:
Subarray Configuration, Capon Metho
Page 61 and 62:
Fig. 2 PMSE plot (SOUSY Svalbard Ra
Page 63 and 64:
VHF radar interferometry had shown
Page 65 and 66:
turbulence. From Figures 1 and 2, i
Page 67 and 68:
SummaryFrom the aspect sensitivity
Page 69 and 70:
a specific range. In this work, syn
Page 71 and 72:
P C(dB)(a) Echo Power60504030200.70
Page 73 and 74:
most occidental area of South Ameri
Page 75 and 76:
Quegan, 1992). It should be useful
Page 77 and 78:
measurements, is shown in figure 1(
Page 79:
The present observations thus empha
Page 82 and 83:
RECENT OBSERVATIONS OF E REGION FIE
Page 84 and 85:
measured spectra in order to separa
Page 86 and 87: drifts at E and F regions heights b
Page 88 and 89: • Are characterized by type II ec
Page 90 and 91: The main parameters that could be o
Page 92 and 93: THE ROLE OF UNSTABLE SPORADIC-E LAY
Page 94 and 95: (σ H / σ P )E y (where σ H and
Page 96: STUDY OF A LOW E-REGION QUASI-PERIO
Page 99 and 100: 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: electric fields map along the geoma
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 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
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
Page 225 and 226:
is calculated from the radiosonde t
Page 227 and 228:
Figure 3: Time-altitude cross-secti
Page 229 and 230:
Absorption of cosmic noise is cause
Page 231 and 232:
Incoherent scatter spectracompared
Page 233 and 234:
variations of spectral widths, refr
Page 235 and 236:
Figure 1. Diurnal variation of Turb
Page 237 and 238:
further experimental test of the ST
Page 239 and 240:
waves can be observed more clearly
Page 241 and 242:
winter and a minimum in summer near
Page 243 and 244:
The main recently assumed mechanism
Page 245 and 246:
Figure 2. Statistics of numbers of
Page 247 and 248:
LIDAR OBSERVATIONS OF MIDDLE ATMOSP
Page 249 and 250:
latitudinal dependence of the seaso
Page 251 and 252:
APPLICATION OF THE DUAL-BEAMWIDTH M
Page 253 and 254:
Figure 2: Mean zonal and meridional
Page 255 and 256:
JLKLLK/ILIL6II/G/II/G/LEODFLK/LO/DD
Page 257 and 258:
The monthly diurnal mean of horizon
Page 259 and 260:
Session I.4: Meteorological Phenome
Page 261 and 262:
Integration of the VHF wind profile
Page 263 and 264:
Figure 1 : Map of the Lago Maggiore
Page 265 and 266:
precipitating clouds, the cyclonic
Page 267 and 268:
Eyewall(a)(b)(c)(d)Fig. 3: Radius-h
Page 269 and 270:
as low as 0.55. The Piura 50-MHz ra
Page 271 and 272:
place features in the profile with
Page 273 and 274:
• Period 1 (June 1-10): SCCs exis
Page 275 and 276:
Sumatera occurs by stratiform cloud
Page 277 and 278:
very interesting to note the double
Page 279 and 280:
20(a) Convective Region(b) Transiti
Page 281 and 282:
Typhoon LekimaFig. 2 Typhoon Lekima
Page 283 and 284:
Fig. 5 Passage of typhoon Hayan on
Page 285 and 286:
the 50 cm 2 sensor head, enabling t
Page 287 and 288:
22 June 2000 23:22:23 - 23:24:20 at
Page 289 and 290:
the time-height section of a convec
Page 291 and 292:
Thurai, M., T.Iguchi,T. Kozu, J.D.E
Page 293 and 294:
There are two main mechanisms which
Page 295 and 296:
Horel, J.D. and Cornejo-Garrido, A.
Page 297 and 298:
estimating two independent and redu
Page 299 and 300:
RASS THETA (K) RASS v-component (m/
Page 301 and 302:
Surface winds usually range from 10
Page 303 and 304:
weak (maximum of 5 m s -1 ) and the
Page 305 and 306:
The vertical component from the VTB
Page 307 and 308:
Figure 8 shows the profile of virtu
Page 309 and 310:
2 3D ( , ) ( ) ( ) ˆ ( ) ˆp∆ xm
Page 311 and 312:
presented in Praskovsky et al. (200
Page 313 and 314:
In Fig. 2 a sketch of a mountain le
Page 315 and 316:
In Fig. 8 the lamina is aligned on
Page 317 and 318:
Figure 1: composite day (13 days) o
Page 319 and 320:
virtual sensible heat fluxes ( Wm-2
Page 321 and 322:
3. Characteristics of precipitation
Page 323 and 324:
Fig. 3: Horizontal distribution of
Page 325 and 326:
3. Results and discussionUHF profil
Page 327 and 328:
Figure 4. Monthly variation of slop
Page 329 and 330:
system with two receiving antennae,
Page 331 and 332:
cycle of precipitation. Figure 3(a)
Page 333 and 334:
Histogram of Zonal Velocityh=5.13 K
Page 335 and 336:
5. Summary of results and concludin
Page 337 and 338:
the two nearby major cities, Chenna
Page 339 and 340:
Boundary layer height, km32.521.5(a
Page 341 and 342:
Figure 1:Data from the MST radar at
Page 343 and 344:
spectral processing. In this partic
Page 345 and 346:
3. Results and discussionIn the pre
Page 347 and 348:
4. SummaryAn attempt has been made
Page 349 and 350:
The purpose of this study is to exa
Page 351 and 352:
Figure1. Three-day average of momen
Page 353 and 354:
3. The improved method to estimate
Page 355 and 356:
But in case of period until 1800 UT
Page 357 and 358:
Session I.5: Operational Aspects an
Page 359 and 360:
The profilers of WINDAS weredesigne
Page 361 and 362:
NOAA, 1994 : Wind profiler assessme
Page 363 and 364:
FIRST RESULTS OF THE BOUNDARY LAYER
Page 365 and 366:
Figure 3. Pulse Design Diagram to s
Page 367 and 368:
MOVEABLE UHF/S-BAND PROFILER/DISDRO
Page 369 and 370:
one-minute Z values determined from
Page 371 and 372:
TOWARD A MULTISENSOR GROUND BASED R
Page 373 and 374:
3. Cloud Evolution Case StudyOn the
Page 375 and 376:
DEVELOPMENT OF A DIGITAL RECEIVER F
Page 377 and 378:
Experiment 1 Experiment 2IPP 999Km
Page 379 and 380:
ELECTRONIC DIGITAL BEAMFORMING IMPL
Page 381 and 382:
The main element of the unit (figur
Page 383 and 384:
.ON-LINE ADAPTIVE DC-GROUND-CLUTTER
Page 385 and 386:
esulting in a widening of the bandw
Page 387 and 388:
ON THE RADIATION EFFICIENCY OF COCO
Page 389 and 390:
Table 2: Experiment #1 results, Tra
Page 391 and 392:
A NEW NARROW BEAM MF RADAR AT 3 MHZ
Page 393 and 394:
Off-zenith beams towards N, S, E, W
Page 395 and 396:
95ALWIN VHF radar: signal powerdB80
Page 397 and 398:
ANTENNA BEAM VERIFICATION USING COS
Page 399 and 400:
Figure 2: A 45 MHz reference sky te
Page 401 and 402:
AN ATTEMPT TO CALIBRATE THE UHF STR
Page 403 and 404:
is at 4.7 km, but in the first 4-ga
Page 405 and 406:
QUALITY CONTROL FOR DOPPLER WIND PR
Page 407 and 408:
The resulting moments are subjected
Page 409 and 410:
SOUSY RADAR AT JICAMARCA: SYSTEM DE
Page 411 and 412:
NEControl andcomputer roomCompCoute
Page 413 and 414:
THE EQUATORIAL ATMOSPHERE RADAR:SYS
Page 415 and 416:
Table 1: Specifications of the EAR
Page 417 and 418:
VHF ATMOSPHERIC AND METEOR RADAR IN
Page 419 and 420:
ased upon a geotechnical engineerin
Page 421 and 422:
VORTICAL MOTIONS OBSERVED WITH THE
Page 423 and 424:
interpolation from the original gri
Page 425 and 426:
A NEW MINIRADAR TO INVESTIGATE URBA
Page 427 and 428:
e eliminated to analyze correctly t
Page 429 and 430:
Session PWG 1: System Calibrations
Page 431 and 432:
Session PWG 2: Data Analysis, Valid
Page 433 and 434:
• the time series vectors x(k) of
Page 435 and 436:
Fig. 4: reflectivity of the hydrome
Page 437 and 438:
Session PWG 3: Accuracies and Requi
Page 439 and 440:
Session PWG 4: International Collab
Page 441 and 442:
Session II.E: NOVEL PERSPECTIVES AN
Page 443 and 444:
2 Proposed AlgorithmReceived signal
Page 445 and 446:
N#4E-1-16E1A1#1#2A-1-1C1#3C-1-19Fig
Page 447 and 448:
of conventional DCMP, with which th
Page 449 and 450:
applying the directional constraint
Page 451 and 452:
while for a beam of finite width, t
Page 453 and 454:
In order to make the process more q
Page 455 and 456:
WHAT IS TURBULENCE SEEN BY VHF RADA
Page 457 and 458:
Enhanced resolution applyingpulse s
Page 459 and 460:
Beckmann, Spizichino, 1964Fig. 8 Po
Page 461 and 462:
Fig. 11 Plots of temporal variation
Page 463 and 464:
Fig. 14 Distributions of phase cent
Page 465 and 466:
Hocking, W.K., Radar studies of sma
Page 467 and 468:
THE STRUCTURE FUNCTION-BASED APPROA
Page 469 and 470:
{ Ui( t), Vi( t), Wi( t)} = { Ui ,
Page 471 and 472:
161). Assumption 2H: the instantane
Page 473 and 474:
Only the second order SF are consid
Page 475 and 476:
fluctuations umk( t ) along the bas
Page 477 and 478:
VHF PARASITIC RADAR INTERFEROMETRYF
Page 479 and 480:
• All the costs of transmitter pr
Page 481 and 482:
Figure 2: Example of range-azimuth
Page 483 and 484:
Target Altitude, km1009080706050403
Page 485 and 486:
ReferencesGriffiths, H. D., A. J. G
Page 487 and 488:
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. .......................
show all

Proceedings with Extended Abstracts (single PDF file) - Radio ...

Create successful ePaper yourself

Delete template?

Save as template?