AMISR Contributions to Equatorial Aeronomy

Transcription

1 AMISR Contributions to Equatorial Aeronomy p. 1/2 AMISR Contributions to Equatorial Aeronomy D. L. Hysell and J. L. Chau Earth and Atmospheric Sciences, Cornell University, Ithaca, New York Jicamarca Radio Observatory, Lima, Peru

2 AMISR Contributions to Equatorial Aeronomy p. 2/2 AMISR-8 system description Parameter Transmit frequency Transmit peak power Transmit average power Transmit pulse width Antenna Receiver front end Receiver back end value MHz 128 kw 12.8 kw 1µs 2 ms crossed dipole array (circular pol.) 8 panels of 32 elements, 3.5 m x 2 m low-noise transistor amplifier on each element digital receiver PC level boards

3 AMISR Contributions to Equatorial Aeronomy p. 3/2 Gallery Range (km) Mean SNR (db) :58 6:59 7:00 7:01 7:02 7:03 7:04 7:05 7:06 7:07 7:08 7:09 7:10 7:11 7:12 7:13 Local Time Day: 18-Nov

4 Gallery II AMISR Contributions to Equatorial Aeronomy p. 4/2

5 Bottom-type layers AMISR Contributions to Equatorial Aeronomy p. 5/2

6 Shear flow Height (km) Height (km) (a) Jicamarca Vertical Drifts (m s -1 ) (b) Jicamarca Zonal Drifts (m s -1 ) Local Time: From: 11-Nov-2002 (315) to: 15-Nov-2002 (319) AMISR Contributions to Equatorial Aeronomy p. 6/2

7 AMISR Contributions to Equatorial Aeronomy p. 7/2 Aperture synthesis imaging Apr. 25, 2000 Apr. 25, cont Nov. 27, 2003 Nov. 27, cont Nov. 27, cont

8 2D Simulation AMISR Contributions to Equatorial Aeronomy p. 8/2

9 AMISR Contributions to Equatorial Aeronomy p. 9/2 AMISR investigation Can we identify and understand spread F precursor waves?

10 AMISR Contributions to Equatorial Aeronomy p. 10/2 Plume morphology Feb cont. cont. cont.

11 AMISR Contributions to Equatorial Aeronomy p. 11/2 AMISR investigation Can we identify and understand spread F precursor waves? How does radar plume morphology relate to the underlying plasma depletion?

12 AMISR Contributions to Equatorial Aeronomy p. 12/2 Doppler spectra simulation

13 AMISR Contributions to Equatorial Aeronomy p. 13/2 Theory and experiment D(t) x2 2t = 1 t B 2 E(0) E(τ) dτ 0 = 2dR(t)/dt n (k, t)n(k, t + τ) = n(k, t) 2 e k2 R(τ) 1 2 ( dr dτ ) 2 = 1 ( 1 exp( 2k 2B 2 E(k) 2 2 ) R) 2k 2 k

14 AMISR Contributions to Equatorial Aeronomy p. 14/2 AMISR investigation Can we identify and understand spread F precursor waves? How does radar plume morphology relate to the underlying plasma depletion? How should we interpret the Doppler spectrum of F region plasma irregularities?

15 Electrojet waves AMISR Contributions to Equatorial Aeronomy p. 15/2

16 Linear, local theory k (V de V di ) ω = (1 + ψ)(1 + k /k 2 2 ) + k V di γ = ψ/ν ( ) i (ω k V di ) 2 k 2 Cs ψ + k k (ω k V di) 2αn k k = ψ k k 2 L ν i Ω i, ψ ν eν i Ω e Ω i ( 1 + Ω2 e ν 2 e k 2 k 2 ) daytime sunset nighttime AMISR Contributions to Equatorial Aeronomy p. 16/2

17 AMISR Contributions to Equatorial Aeronomy p. 17/2 Pure two-stream waves a c b

18 Counter electrojet a) 10:43:20 c) Range: km 60.0 b) Power (db) Range (km) Radial Velocity (m/s) f) Range: km d) 10:43: Width (m/s x 0.5) e) Power (db) Range (km) Radial Velocity (m/s) i) Range: km g) 10:44: Width (m/s x 1.0) h) Power (db) Range (km) Radial Velocity (m/s) Width (m/s x 2.0) AMISR Contributions to Equatorial Aeronomy p. 18/2

19 AMISR Contributions to Equatorial Aeronomy p. 19/2 AMISR investigation Can we identify and understand spread F precursor waves? How does radar plume morphology relate to the underlying plasma depletion? How should we interpret the Doppler spectrum of F region plasma irregularities? How should we interpret Doppler spectra due to pure two-stream turbulence in the electrojet?

20 AMISR Contributions to Equatorial Aeronomy p. 20/2 Frequency effects Balsley and Farley [1971], Farley and Fejer [1975]

21 Auroral electrojet AMISR Contributions to Equatorial Aeronomy p. 21/2

22 AMISR Contributions to Equatorial Aeronomy p. 22/2 AMISR investigation Can we identify and understand spread F precursor waves? How does radar plume morphology relate to the underlying plasma depletion? How should we interpret the Doppler spectrum of F region plasma irregularities? How should we interpret Doppler spectra due to pure two-stream turbulence in the electrojet? How does the radar backscatter depend on frequency?

23 East-west asymmetry AMISR Contributions to Equatorial Aeronomy p. 23/2

24 Acoustic speeds and winds AMISR Contributions to Equatorial Aeronomy p. 24/2

25 AMISR Contributions to Equatorial Aeronomy p. 25/2 AMISR investigation Can we identify and understand spread F precursor waves? How does radar plume morphology relate to the underlying plasma depletion? How should we interpret the Doppler spectrum of F region plasma irregularities? How should we interpret Doppler spectra due to pure two-stream turbulence in the electrojet? How does the radar backscatter depend on frequency? What causes the east-west asymmetry?