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TROPOSPHERIC WINDS MEASURED WITH THE PIURA ST RADAR:NORMAL VS. “EL NIÑO 1997-98” CONDITIONSLuis A. Flores 1 , Jacqueline La Madrid 1 , Jorge L. Chau 21 Laboratorio de Física, Universidad de Piura, Apartado 353, Piura, Peru2 Radio Observatorio de Jicamarca, Instituto Geofisico del Perú, Apartado 3747, Lima, PeruAbstract. The Piura ST (Stratosphere-Troposphere) radar was installed by NOAA AeronomyLaboratory in 1989 as part of a Trans-Pacific network of wind profilers to study the loweratmospheric dynamics associated with El Niño phenomenon (Gage et al., 1990). In this workwe summarize the statistical characteristics of the horizontal winds observed over Piurabetween 1991 and 2002. The behaviour of the horizontal wind components are shown anddiscussed as a function of their altitudinal, diurnal and seasonal characteristics. The analysishas been performed for both, normal conditions (periods without El Niño) as well as, for thestrong 1997-98 El Niño event. In addition, the horizontal wind characteristics are shown forthe two seasons prior to the El Niño 1997-98 event. Our results suggest the existence of twopotential precursors in the upper tropospheric horizontal winds when a strong event isinvolved.1. Piura VHF Radar.The Piura VHF radar is located in northern Peru (05°10'S, 80° 38'W) approximately 60 km towest of the Andes. It is a ST (Stratosphere, Troposphere) radar. This radar was installed in1989 measuring at the beginning just the vertical wind (Ragaini and Rodríguez, 1992). InFebruary of 1991 the radar system was upgraded with oblique rays (14°S and 14°E) allowingthe measurement of the horizontal wind components. This radar uses a COCO antenna arrayof 100m x 100m (Judasz et al., 1987). More details of the system can be found in Gage et al.[1991].2. Methodology and statistical analysis.We have analysed wind information from February, 1991 to December, 2002 to obtain theseasonal and diurnal characteristics of the horizontal velocity. The seasons considered are (a)Austral summer (21 Dec-20 Mar), (b) Austral autumn (21 Mar-20 Jun), (c) Austral winter (21Jun-22 Sep), and (d) Austral spring (23 Sep-20 Dec). The wind convention is as follows:positive to the east and north for the zonal and meridional wind, respectively.Distribution of frequency We have generated and analysed histograms for the speedcorresponding to several years and to several heights. The characteristics and distribution offrequency are studied for annual periods. Thus we have determined the arithmetic mean,mode, variance, standard deviation, coefficient of asymmetry and coefficient of Kurtosis ofthe horizontal components of wind. Similar analysis we can see in Nastrom et al., 1996.The data collection of zonal and meridional velocity follow a normal distribution. In figures1a and 1b we show histograms of zonal and meridional velocities observed in 1993. Similarresults were obtained for other periods and altitudes.326
Histogram of Zonal Velocityh=5.13 Km - Year 1993Histogram of Maridional Velocityh=5.13 Km - Year 1993frequency600500400300200100avg= -4.27stand. dev=3.600-17.0 -12.0 -7.0 -2.0 3.0 8.0frecuencia700600500400300200avg= -0.44stand. dev=2.781000-11.5 -5.5 0.5 6.5 12.5Figure 1. Annual distribution of (a) zonal and (b) meridional velocity, respectively, for 5.13-kmaltitude.In the table 1 we present a summary of the arithmetic measurements obtained for 1993. Wecan see a good agreement between mean arithmetic, median and mode values for the zonalvelocities. Also, it is necessary to stand out that the moments of superior order like theasymmetry coefficient and the kurtosis are close to zero. These results suggest that the zonaland meridional winds follow a distribution of normal frequency. Similar behaviour has beenobserved in other years.Table 1: Arithmetic measures from 1993Summay of Arithmetic Measurements Year 1993Zonal VelocityHeight (km) 1.77 2.73 3.69 4.65 5.13 5.61 6.09 6.57 7.05 7.53Arithmetic mean -1.070 -2.011 -3.893 -4.557 -4.273 -4.089 -4.039 -3.987 -3.861 -3.716Median -1.010 -1.970 -3.860 -4.520 -4.360 -4.330 -4.290 -4.130 -4.180 -4.000Mode -0.950 -1.770 -4.460 -3.330 -4.790 -5.200 -5.100 -4.340 -4.560 -5.080Standard Deviation 1.840 2.202 3.205 3.747 3.597 3.479 3.508 3.638 3.958 4.185Asymmetry coefficent 0.002 -0.139 -0.142 -0.019 0.104 0.350 0.546 0.526 0.499 0.469Kurtosis 1.814 0.442 0.100 -0.064 0.186 0.576 1.189 1.245 1.402 1.250Total data 8279 8279 8278 8277 8273 8270 8270 8170 7834 7438Meridional VelocityHeight (km) 1.77 2.73 3.69 4.65 5.13 5.61 6.09 6.57 7.05 7.53Arithmetic mean -0.143 0.168 -0.291 -0.467 -0.444 -0.602 -0.812 -0.880 -0.831 -0.712Median -0.060 0.170 -0.380 -0.370 -0.320 -0.560 -0.810 -0.950 -0.990 -0.900Mode 0.410 -1.740 -0.620 -1.090 0.830 0.760 -0.570 -1.770 -2.360 -1.310Standard Deviation 3.263 2.975 2.461 2.718 2.779 2.821 2.903 2.992 3.236 3.411Asymmetry coefficent -0.088 -0.061 0.118 -0.198 -0.304 -0.261 -0.200 0.024 0.181 0.348Kurtosis 0.106 0.430 0.827 0.772 0.623 0.550 0.631 0.521 3.730 0.978Total data 8275 8273 8272 8270 8264 8265 8266 8131 7808 73513. Indicators of El Niño and the Southern Oscillation consideredWe have obtained the seasonal profiles for El Niño and no Niño conditions. To determine ifEl Niño events, we have used standard atmospheric and oceanic indicators. The criteria for ElNiño events werei. That the monthly Southern Oscillation Index (SOI) is smaller than –1. According to theCDB No. 00/08 of CPC-NOAA.ii.That the Superficial Sea Temperature Anomaly (SSTA) is same or bigger than 1 °C in theregions Niño1+2, Niño 3, Niño 4 and Niño 3-4 of the Tropical Pacific. According to theCDB, No. 98/08 of CPC-NOAA based on series 1961-1990 (Smith and Reynolds, 1995).327
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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,
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matter daytime or nighttime and are
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two sub-arrays, each sub-array made
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4. SummaryHere we describe a radio
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Figure 1. E-region DPS4 spectra, ri
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effects. It is therefore plausible
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1996 and high in 2002). The electri
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electric fields map along the geoma
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SNR condition is always difficult a
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Figure-4 Power spectrum plots of a
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As we show below, Jicamarca offers
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particularly during daytime counter
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where ˆδ nm = (δ l − δ m )
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PMSE is more easily interpreted as
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ResultsTemperature climatology• s
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Simultaneous PMSE and NLC observati
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ResultsSeasonal variationMSE are no
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Figure 2: MSE parameters as functio
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Session I.3: Winds, waves and turbu
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poor. It was shown that poor perfor
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The use of diffraction pattern simi
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F 13 (ξ x ′) = (1 − cos 2ψ N)
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Figure 3: (a) Baseline length depen
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3. ResultsFigure 1 shows the amplit
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variability.Figure 4 shows the aver
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Figure 1. Period-time amplitude wav
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the 12-h and 24-h periodicities in
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winds and variances at altitudes 70
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similar correlation with larger mag
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of the refraction index are not equ
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Fig. 8. Zonal wind (top) and temper
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STUDIES ON ATMOSPHERIC GRAVITY WAVE
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1100-1200 hours. From this plot 6.3
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STUDIES ON WINDS AND MOMENTUM FLUXE
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3.4 Monthly variation of momentum f
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DEEP PENETRATIVE CONVECTION AND GEN
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ly changes direction with time with
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189
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191
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193
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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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Page 283 and 284: Fig. 5 Passage of typhoon Hayan on
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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
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Page 307 and 308: Figure 8 shows the profile of virtu
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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
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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
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Page 331: cycle of precipitation. Figure 3(a)
Page 335 and 336: 5. Summary of results and concludin
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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
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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
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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
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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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