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Published byPrudence Parsons Modified over 9 years ago
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First Results from the LYRA Solar UV Radiometer J.-F. Hochedez, I. E. Dammasch, M. Dominique & the LYRA Team COSPAR 38 th Scientific Assembly Bremen 18-25 July 2010 8 th Annual TIGER Symposium LYRA the Large-Yield Radiometer onboard PROBA2
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Royal Observatory of Belgium (Brussels, B) Principal Investigator, overall design, onboard software specification, science operations PMOD/WRC (Davos, CH) Lead Co-Investigator, overall design and manufacturing Centre Spatial de Liège (B) Lead institute, project management, filters IMOMEC (Hasselt, B) Diamond detectors Max-Planck-Institut für Sonnensystemforschung (Lindau, D) calibration science Co-Is: BISA (Brussels, B), LPC2E (Orléans, F)… LYRA highlights
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4 spectral channels covering a wide emission temperature range Redundancy (3 units) gathering three types of detectors Rad-hard, solar-blind diamond UV sensors (PIN and MSM) AXUV Si photodiodes 2 calibration LEDs per detector (λ = 465 nm and 390 nm) High cadence (up to 100Hz) Quasi-continuous acquisition during mission lifetime LyHzAlZr Unit1MSMPINMSMSi Unit2MSMPINMSM Unit3SiPINSi
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SWAP and LYRA spectral intervals for solar flares, space weather, and aeronomy LYRA channel 1: the H I 121.6 nm Lyman-alpha line LYRA channel 2: the 200-220 nm Herzberg continuum range LYRA channel 3: the 17-80 nm Aluminium filter range including the He II 30.4 nm line (+ X-ray) LYRA channel 4: the 6-20 nm Zirconium filter range where solar variablility is highest (+ X-ray) SWAP: the range around 17.4 nm including coronal lines like Fe IX and Fe X
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LYRA pre-flight spectral responsivity (filter + detector, twelve combinations)
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LYRA data products and manuals… …available at the PROBA2 Science Center: http://proba2.sidc.be/
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Summary: FITS File Structure lyra_20100609_000000_lev1_***.fits where: *** = met, std, cal, rej, (bst, bca, bre) generally: header + binary extension table(s) extension = header + data (variable length) Lev1 met = HK, STATUS, VFC Lev1 std = uncalibr. irradiance (counts/ms) Lev2 std = calibr. irradiance (W/m²) Lev3 std = calibr. aver. irradiance (W/m²) per line: time, ch1, ch2, ch3, ch4, qual.
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Product Definition Level 1 = full raw data (LY-EDG output) Level 2 = calibrated physical data (LY-BSDG output) Caution: preliminary status. Require versioning. Level 3 = processed products (e.g. averages) Level 4 = plots of products Level 5 = event lists (optionally with plots)
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Further Data Products… …“Level 4”, “Level 5” (still preliminary):
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LY-TMR: State of the data processing pipeline LY-EDG LY-BSDG Telemetry packets Raw data (in counts) Lv1: Engineering data (in Hz) fits Lv2: Calibrated data (in W/m²) Other tools Higher level data products Current stateIn the future Not distributed Daily basis After each contact Not available After each contact Plots + flare list available irregular systematic
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First results (even before opening covers)
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Aurora Oval Perturbations appearing around 75° latitude 2-3 days after a CME, flare... Associated to geomagnetic perturbations Spacecraft maneuvers SAA
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First Light acquisition (06 Jan 2010)
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Aeronomy Occultations: Study atmospheric absorption; high temporal resolution needed Input for atmospheric models: NRT and calibrated data needed
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Flares LYRA observes flares down to B1.0 LYRA flare list agrees with GOES14 Flares are visible in the two short-wavelength channels Exceptionally strong and impulsive flares are also visible in the Lyman- alpha channel (precursor) Example: C4.0 flare, 06 Feb 2010, 07:04 UTC
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M2.0 flare, 28 Feb 2010, 13:47 UTC
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Comparison with GOES flare Example: M1.8 flare, 20 Jan 2010, 10:59 UTC
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Sun-Moon eclipse …demonstrating the inhomogeneous distribution of EUV radiation across the solar surface
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And we have a fifth channel at 17.4nm...... called SWAP!
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SWAP and LYRA observing together 20100607_proba2_movie.mp4
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Degradation of LYRA units 1 and 3
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Initial degradation of LYRA unit 2 (nom.)
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before & after (& still later) LYRA output, in kHz, incl. dark currents Ch1-1 Ch1-2 Ch1-3 Ch1-4 700 500 20 30 expected 950+ 620 16+ 37 begin Jan 2010 650+ 520 16+ 37 end Apr 2010 Ch2-1 Ch2-2 Ch2-3 Ch2-4 (nominal unit) 260 580 19 42 expected 470 700 23 45 begin Jan 2010 100 100 12 40 end Apr 2010 Ch3-1 Ch3-2 Ch3-3 Ch3-4 685 470 232 29 expected 900 550 280 35 begin Jan 2010 800 500 250 35 end Apr 2010
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before & after (First Light) TIMED/SEE and SORCE/SOLSTICE spectra: 120-123 200-220 17-80 6-20 nm 0.00632022 0.459813 0.00191427 0.000680367 W/m2 LYRA Radiometric Model simulation results with these spectra: ch1-1 ch1-2 ch1-3 ch1-4 0.292925 11.2802 0.0639896 0.106377 nA ch2-1 ch2-2 ch2-3 ch2-4 0.103003 12.0667 0.0576520 0.0154245 nA ch3-1 ch3-2 ch3-3 ch3-4 0.272172 9.69322 1.02496 0.108225 nA LYRA planned level-2 calibration software results with real obs.: ch1-1 ch1-2 ch1-3 ch1-4 930.000 616.000 23.0000 37.0000 kHz 0.378432 12.6978 0.0663619 0.119044 nA 0.0122330 0.515256 0.00192962 0.000781892 W/m2 ch2-1 ch2-2 ch2-3 ch2-4 480.000 710.000 23.0000 46.0000 kHz 0.187329 14.8165 0.0682085 0.0149483 nA 0.0241729 0.564246 0.00208629 0.000698602 W/m2 ch3-1 ch3-2 ch3-3 ch3-4 930.000 550.000 277.000 36.0000 kHz 0.367773 11.3934 1.12775 0.124544 nA 0.0127599 0.539271 0.00200588 0.000800165 W/m2
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Model t = time {1,…,T} T = number of days s(t) = solar data l(t) = LYRA data c(t) = s(t)/l(t) conversion factor => s(i) = c(t)*l(i) {1,…,8 000 000} simple expansion?? c(t) = b*d(t) degradation correction and conversion?? solar = a + b*lyra more realistic, see LRM, thus s(i) = a + b*d(t)*l(i) s(t) – a = b*d(t)*l(t) => T equations for T+2 variables
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Procedure (instead of LRM) Get daily SORCE and TIMED data from the web Calculate degradation correction d(t) and expand with splines Calculate conversion parameters a and b Estimate dark current from past measurements, or from temperatures Estimate missing days with linear extrapolation of d(t) - currently only possible for channels 3 and 4
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Next steps Understand degradation Cross-calibration (internal/external) Produce calibrated data automatically Publish first results Advertise data products Get extension from ESA … (suggestions?)
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