A comparison of automated- search meteor results from radar by lindayy

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									A comparison of automated-
search meteor results from
radar observations at PFISR,
        SRF and AO
  Stan Briczinski
                                         -UW-Madison
  John Mathews
                     -The Pennsylvania State University
  David Meisel
                                      -SUNY Geneseo
  Craig Heinselman
                                     -SRI International
     Scattering Theory

• Meteor “head-echo” scattering is theorized
  as highly frequency dependent
• Previous observations have been frequency
  AND latitude dependent
• AMISR at latitude similar to SRF and
  frequency comparable to AO
 Meteor Observations

• Transmit a 45-90 μs uncoded pulse
• Observe Doppler shifted returns between
  80 and 140 km in range (at zenith)
• 24 continuous hours of sporadic meteor
  observations conducted at PFISR in March,
  June, September and December 2007
                         AMISR                SRF                 AO

     Location        65.12oN, 147.47oW   66.99oN, 50.95oW   18.47oN, 66.73oW

   Beamdwidth              ~ 1o               ~ 1/2o             ~ 1/6o

Transmit Frequency      449.3 MHz          1290.0 MHz         430.0 MHz

System Temperature        120 K               110 K              80 K

   Pulse Length            90 µs              82 µs              45 µs

  Sampling Rate           1 MHz             1.25 MHz            1 MHz

 Operating Power        ~ 1.25 MW           ~ 2.8 MW           ~1.6 MW

   Initial Range         80.0 km             75.5 km            75.0 km

   Final Range           170.0 km           170.0 km           142.5 km

       IPP                 2 ms               3.3 ms             1 ms
 Periodic Searching Algorithm




              FFT




Time Domain         Frequency Domain
    Results - Three Radars

August Observations

        AO      2 hours   2486 events
       PFISR    8 hours    443 events
       SRF     21 hours    322 events
                August Altitude Distributions
                130                                          130


                                         AO                                                       SRF
                                         PF AMISR-32
                120                                          120
Altitude (km)




                110                                          110




                100                                          100




                90                                           90




                80                                           80
                 0.0   0.2   0.4   0.6     0.8         1.0    0.0         0.2   0.4   0.6   0.8         1.0


                                             Relative Number of Meteors
                                  Observation Bias
                130                                       130                                         130




                120                     First IPP         120                         Max S/N         120                      Last IPP
Altitude (km)




                110                                       110                                         110




                100                                       100                                         100




                90                                        90                                           90




                80                                        80                                           80
                  0   0.2   0.4   0.6        0.8    1.0     0    0.2     0.4    0.6       0.8   1.0      0   0.2   0.4   0.6       0.8    1.0


                                                                Relative Number of Meteors
                                    Doppler Distributions
                                         (Summer)
                             1.0                                                   1.0

                                         AO                                                     SRF
                                         PF AMISR-32

                             0.8                                                   0.8
Relative Number of Meteors




                             0.6                                                   0.6




                             0.4                                                   0.4




                             0.2                                                   0.2




                             0.0                                                   0.0
                               10   20           30    40   50   60          70      10         20    30   40   50          60            70
                                                                                                                     Bin Sizes = 2 km/s
                                                                      Doppler Velocity (km/s)
                                         Deceleration Measurements
                                                 (Summer)
                             1.0                                                    1.0

                                                               AO                                                       SRF
                                                               PF AMISR-32

                             0.8                                                    0.8
Relative Number of Meteors




                             0.6                                                    0.6




                             0.4                                                    0.4




                             0.2                                                    0.2




                             0.0                                                    0.0
                                   0   200   400   600   800                 1000         0   200   400   600     800                  1000
                                                                                                                Bin sizes = 10 km/s2

                                                                   Deceleration (km/s2)
         Results - PFISR

PFISR Observations

   March       24 hours    811 events
   June        24 hours   1761 events
   September   15 hours   2380 events
   December    24 hours   2318 events
PFISR Altitude Distributions
                130


                                                       March
                                                       June
                120                                    September
                                                       December


                110
Altitude (km)




                100




                90




                80


                  0.0   0.2     0.4              0.6               0.8   1.0
                              Relative Number of Meteors
             140



                                                                                                                 140
             130
                                                                                                                                                                                 30
                                                                                30




                                                                                                 Altitude (km)
             120
                                                                                                                                                                                 20
                                                                                20                               120
Range (km)




                                                                                                                                                                                       SNR (dB)
                                                                                      SNR (dB)
                                                                                10
                                                                                                                                                                                 10

             110

                                                                                 0                                                                                                0
                                                                                                                 100

             100                                                                -10                                                                                              -10




             90                                                                                                   80


                                                                                                                 500
               4




                                                                                                                 400
               3




                                                                                                                 300
SNR




               2
                                                                                                 SNR


                                                                                                                 200

               1




                                                                                                                 100


               0
                   0   50                100               150            200

                       Time (msec) from 05:17.23.85 AKDT on 01 Aug 2006                                            0
                                                                                                                       0        100             200             300        400
                                                                                                                           Time (ms) past 07:06:08.465 LT on 07 Mar 2007
          Conclusions
• PFISR is a useful tool in meteor head echo
  scattering theory
• At high latitudes there is an apparent
  seasonal shift in the “meteor ceiling”
• The end of the Brett Favre crisis has allowed
  the resumption of data processing at UW-
  Madison

								
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