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THEMIS GBO data and data products. by THEMIS GBO team*.

THEMIS GBO data and data products. by THEMIS GBO team*. Presentation prepared by:

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THEMIS GBO data and data products. by THEMIS GBO team*.

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  1. THEMIS GBO data and data products. by THEMIS GBO team*. Presentation prepared by: S. B. Mende1, H.U. Frey1, E. Spanswick21Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA2University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canadae-mail: mende@ssl.berkeley.edu

  2. THEMIS GBO Team • University of California – Berkeley (UCB) • S. B. Mende – GBO science lead • H. U. Frey, S. Harris, W. Rachelson, R. Sterling • Provides ASI development, system engineering, GBO system fabrication and construction, data archive and dissemination • University of Calgary • E. Donovan – Canadian science lead • E. Spanswick, B. Jackel, M. Greffen • Providing GBO system deployment in Canada, field management, data collection, development participation • University of California – Los Angeles (UCLA) • C. T. Russell – magnetometer science lead • Develop and provide ground magnetometer for GBO / EPO • University of Alberta • I. Mann – magnetometer scientist • Providing access to Canadian magnetometer network

  3. GBO Science Objective Central issue to THEMIS - Substorm onsets timing and location. Global images taken from high altitude satellites e.g. IMAGE FUV produced such images. How to do it (and better) without global auroral imaging? GBO shall monitor the auroral light and ionospheric currents across North America in order to localize the time, location, and evolution of the auroral manifestation of the substorm. Themis mission requirement relating to GBO: Determine substorm onset time and substorm meridian magnetic local time (MLT) using All Sky Imagers (one ASI per MLT hr) and Ground Magnetometer (two GMAG per MLT hr) with t_res<30s and dMLT<1° respectively, in an 8hr geographic local time sector including the US.

  4. THEMIS GBO

  5. GBO Derived Requirements

  6. ASI Requirements

  7. THEMIS GBO network 20 sites operational in 2007 21 sites operational since October 2008, incl. 3 relocations by U. Calgary

  8. THEMIS GBO history GBO Data Version History GBO install ... Full GBO compliment installed. L1 data produced 2007/01/01 2009/01/01 2008/01/01 Earlier imager data formats were recorded during testing in 2003-2006. By early 2006, all installed imagers were recording the current L1 data format. GBO magnetometers do not have data format revisions, L1 data was recorded from installation. GBO Imager Metadata History Imager “skymaps” (pointing information) are updated once per imaging season and in response to changes in imager orientation due to building shifts, camera replacement/maintenance, etc. KUUJ Shift All skymaps updated 2007/01/01 2009/01/01 2008/01/01 All skymaps are available online at http://themis-data.phys.ucalgary.ca/data/skymap/ and are used by the themis software.

  9. GBO data products • ASI keograms along local magnetic meridian • Delivered daily jpeg-compressed (Level-0) • Reprocessed ½ year later with full resolution images (L1) • Geomagnetically mapped thumbnail images • Delivered daily square-root intensity compression (L0) • 1024 pixels within +-8o magnetic Latitude and ~+-12o Longitude • 3 seconds temporal resolution, 8-bits • Full resolution images (L1) • 256x256 pixels covering about 600 km radius around station • Delivered about ½ year later • 3 seconds temporal resolution • Full 16 bit intensity scale Geomagnetic field measured at 2 Hz (Level-2) Calibrated GMAG data (L2) available at THEMIS and SPDF sites. THEMIS Pseudo AL index is routinely produced (L1 product). Delivered daily from GBO-sites, short delay from additional networks (CHARISMA, UAF, Greenland)

  10. Data products on web page Overview plots Mosaics and Movies CDF-files for data download

  11. All-sky imager performance Monitor position and brightness of Polaris in Gillam (left) and Fort Yukon (right) Position shows when camera was moved Over 3 years decrease in response 3% (GILL) and 6% (FYKN)

  12. Publications and data access • - So far >100 THEMIS-Publications in refereed journal (November 1, 2009) • - 35% publications used GBO data • Note: Bow shock and MP studies rarely use any ground-based data (exception: THEMIS and Antarctic ground based data is used in Mende et al. (2009), J. Geophys. Res., 114, A00C23, doi:10.1029/2008JA013496. Data access and download through UCB-SSL web Site (to 11/01/09) http://themis.ssl.berkeley.edu/data_processing_check/ground_data_mirrors/ Mag.: 421 distinct users view summary plots, ~400,000 CDF file downloads ASI: 1146 distinct user view summary plots, ~226,000 CDF file downloads Data access and download through U. Calgary site: http://themis-data.phys.ucalgary.ca:8080/data/imager/ [including test (<2006) data] http://themis-data.phys.ucalgary.ca:8080/data/fluxgate/ Virtual Observatory Access: http://www.gaia-vxo.org/ - Data is ingesting nightly

  13. Back up slides

  14. ASI Specifications • Imager: • Field of View: 170º full angle • Spectral passband: 400 – 700 nm (with IR filter) • Sensitivity: < 1kR (5:1 S/N) • Spatial resolution: 290 pixel diameter all-sky-image • Exposure duration: programmable, 1 sec typical • Cadence: 5 s demonstrated, 3 s appears feasible • Enclosure: • Operate in external ambient –50º to +40ºC • Maintain internal temperature at 20º ± 10ºC • Requires about 150 W heating worst case • Hermetically sealed unit w/ nitrogen purge • Dessicant used for field repair • Hermetically sealed electrical connectors • Polycarbonate/acrylic dome • Flexible mounting

  15. Mag Requirements & Specifications • System Features • GPS Receiver Antenna and Electronics Integrated into one package May be located >30M from host (RS422 signals)  NTP compatible (1msec time accuracy) • Flxugate Magnetometer •  ±72KnT dynamic range @ 0.01nT Resolution (~23 bits) Offset DAC system for 256 possible ranges per axis  2 Vectors per second data rate Low Power < 4W Small Size 22cm x 13cm x 5cm Ruggedized All Weather Sensor Design USB interface for data retrieval and firmware upload

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