1 / 41

THE CANADIAN BREWER SPECTROPHOTOMETER NETWORK (CBSN)

THE CANADIAN BREWER SPECTROPHOTOMETER NETWORK (CBSN). by: Tom Grajnar Ozone and UV Network Manager. The Brewer Spectrophotometer: A Canadian Contribution to the Global Ozone and UV Monitoring Programme.

moisesa
Télécharger la présentation

THE CANADIAN BREWER SPECTROPHOTOMETER NETWORK (CBSN)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. THE CANADIAN BREWER SPECTROPHOTOMETER NETWORK(CBSN) by: Tom Grajnar Ozone and UV Network Manager

  2. The Brewer Spectrophotometer: A Canadian Contribution to the Global Ozone and UV Monitoring Programme • Developed to replace Dobson spectrophotometer as prime standard for ground-based ozone monitoring • Is a modified Ebert spectrophotometer that can be used to measure total column ozone, SO2, NO2, ozone profile, aerosol optical depth and temperature of the ozone layer • 1979-Development began at MSC • 1980-Working prototype displayed at QOS in Boulder • 1980-Initiation of Commercial production at SCI-TEC (now Kipp & Zonen) • 1982-First foreign MKII delivered to Greece • 1985-First MKIV • 1987-Patented by Kerr et al. • 1992-First MKIII • 1997-First MSC MKV • 2000-Over 165 Brewers in 43 countries and Antarctica

  3. CBSN: History • 1957 to 1962 - Implementation of Dobson Network – 5 stations • 1982 to 1994 – Implementation of Brewer Network – 13 stations

  4. CBSN: Present State • Canada: • 13 stations • 28 Brewer spectrophotometers (+31 computers) • 1 Dobson spectrophotometer • United States: • 1 station (Mauna Loa Observatory, Hawaii) • 2 Brewer spectrophotometers (+3 computers)

  5. CBSN: Station Location and Instrumentation

  6. CBSN: Station Map

  7. CBSN Management and Maintenance: Purpose • Long-term monitoring of total column ozone and solar spectral ultraviolet radiation • Provision of near real-time data for use in CMC ozone and UV forecasts • Submission of data to WOUDC for long-term archival (trends studies) • Ozone transfer calibrations— for other organizations

  8. CBSN Management and Maintenance: Staff • Direct • Network Manager • Network Technologist • Three Interns (9 months each) • One intern supporting network operations • Two interns writing software • Indirect • Station employees • Station contractors

  9. CBSN Management and Maintenance:Key Operational Tools • Budget spreadsheets • Brewer parts inventory database • Electronic station Log Forms • Various other databases

  10. CBSN Management and Maintenance:Key Operational Tools – Parts Inventory Database • Microsoft Access Database • Over 800 entries • Information: • Product ID# • Product Name • Product Description • Kipp & Zonen or Supplier Part #’s and Prices • Storage Location • Quantity in stock • Quantity required in stock • Quantity to order

  11. CBSN Management and Maintenance:Key Operational Tools – Log Form • Excel workbook • One sheet per month • One Log File per year • Sections: • Contact information • Daily checks • Notes for proper Brewer operation and maintenance • Frequency of non-daily checks • Table to log non-daily checks • Table to log other maintenance notes

  12. CBSN Management and Maintenance:Station Visits -- Overview • For: calibrations, maintenance, repairs, training • Visit frequency: every 2 years • Ideal staff complement: 2 • Duration: about 6 days incl. travel time • Equipment: about 450 kg • Completed so far this year • Alert • Additional station visits this year: • Goose Bay, Dartmouth, Montreal, Mauna Loa?

  13. CBSN Management and Maintenance:Station Visits -- Agenda • Calibration reference + details • Preliminary diagnostics examination • Initial Calibrations (Dispersion, UV, Ozone, etc.) • Maintenance + repairs (260 checks) • New equipment installation + upgrades • Final Calibrations (Dispersion, UV, Ozone, etc.) • Calibration data processing • Installation of new constants • Computer maintenance (15 checks) • Station inventory (50 checks) • Station photos + panorama • GPS station coordinates check • Training • Report finalization

  14. CBSN Management and Maintenance:Station Visits – New Activities • Pressure test all Brewers • Installation of a sky cameras • Installation of a land cameras

  15. CBSN Management and Maintenance:Station Visits – Future Upgrades • Humidity sensors • External desiccant system (closed cases) • Sky and land cameras • Proportionally controlled heaters with fans • Umkehr measurements at all stations • NO2 measurements where possible • Insulated covers for Arctic and northern stations

  16. CBSN Management and Maintenance: Arctic Strategy • Historically the most problematic • Network Brewers range in age from 6 to 21 years -> average = 18 years • Arctic challenges: • High employee/contractor turnover (or no staff) • High cost of non-scheduled station visit • High cost of shipping parts back and forth for testing • Time lag due to infrequent flights, wx conditions employee/contractor time available to test/diagnose • Two Brewers each with one computer • Alert: red + single, Eureka: red + double, Resolute: red + single • Benefits: • Dramatic reduction in data record gaps • Red vs regular Brewer ozone measurement studies • Spare + diagnostic equipment already there • Data comparison

  17. Software Tools: Calibration Software • Ozone calibration: intcom3a/BfilePro • Dispersion calibration: DisPro • UV calibration: LampsPro • Temperature coefficients: TempCoef • GS scan analysis: GraSPro • Mirror positioning: Et.rtn • Neutral density filter test: Testfw2 • Sunscans: IdealStepNumber • Zenith sky coefficients: FullZen

  18. Calibration Procedures: UV Calibration • Irradiance source: 1,000 Watt DXW NIST traceable lamps • Lamps operated at 8.0 amps DC in horizontal position • 40 cm distance from middle of lamp filament to teflon diffuser • Lamp system components: • Power supply: Xantrex model XHR 150-7 • 8.3 amp current limit and 16-bit resolution with RS232 interface • Digital Voltmeter: HP Model 34420A nono-volt/micro-Ohm meter • 7.5 digits resolution • Shunt: Isotek model RUG-Z-R100-0.1 • 0.1 ohm resistor (0.1% tolerance, 1ppm/degree C TCR) • Reference precision standard resistor: Guildline model 9222/0.05 Resistor s/n 33635 • Computer: IBM compatible with RS232 interface for instrument control

  19. Calibration Procedures: UV Calibration • Computer controls power supply and DVM via a single serial port • The current is set to 8.0 amps • Every 10 seconds voltage across shunt is measured and checked to be within 0.0014% of 8.0 amp target • Adjustments are made as required to satisfy this criteria

  20. The Brewer Reference Triad • Established in 1984 • Consists of Brewers 008, 014 and 015 • Each Brewer is calibrated absolutely and independently • Each of the triad goes to MLO for a two week period at least every 8 years to collect data for an absolute calibration • Any refurbishment or changes to the instrument are done at this time • Not a requirement that the same instruments remain part of the triad even though this has been the case • The long-term mean standard deviation among the 3 instruments is < 1%

  21. Implementation and Maintenance of the CBSN Traveling Standard Brewer • Primary and backup traveling standards • Instruments must demonstrate high quality diagnostics and good stability • SL ratios and other diagnostics are checked before leave MSC, on arrival at station and on return to MSC • Calibrated against the triad at least annually, more frequently if concerns exist

  22. Software Tools: Remote Control Software • PCAnywhere 9.2 • Used for: • Diagnostics • Testing • File upload/download • Connections: • 5 stations with TCP inside MSC firewall • 2 stations with TCP outside MSC firewall • 6 stations with modem outside MSC firewall

  23. Software Tools: Brewer Control Software • Network Brewer software: v3.75e/3.75f • VB6.0 Brewer software in development: • Temporary setback—loss of programmer • Two intern programmers for 9 months • About 85 of the 100 routines completed • Will support all Brewer models and all 3 electronic board configurations • Completion of Stage II could be as soon as September 2003 followed by submission to interested parties for Beta testing and comment

  24. Data Transfer from Stations • Ozone and uv bulletins (and some images several times per hour from each Brewer to CMC (and GTS) and to MSC website • All new Brewer data, program, constants, log and image files on a daily basis to CBSN server • WOUDC downloads files from CBSN server daily

  25. Data Quality Assurance Procedures • First level Q/A—Real-time Bulletins • Automatically displayed to desktop computer screens • Compare ds ozone with uv ozone • Note time of last bulletin to ensure continuous operation • Second level Q/A • Monthly diagnostics checks—action as required • Monthly Log Form checks—Feedback to station operators • Final Data Q/A • Data processing and submission to WOUDC by Vitali Fioletov

  26. Final Processing of Observations from Individual Stations: New BDMS Software • Processes B- and UV-files at the same time • Calculates ozone and UV from raw counts • Works directly with ICF and DCF files • “Flexible” SL test correction • Allows specification of time window and weighting function • Typically use median value which works well with spikes and calibrations • HG test-based quality control • Rejection of data if hg after data changes by more than 3 to 5 steps or if low correlation coefficient • If before hg is bad then data acceptance constraints are tougher • If before and after hg are bad then data is rejected • Outputs daily ozone values and individual measurements in ExtCSV format

  27. Final Processing of Observations from Individual Stations: New UV Algorithm • Linear responsivity interpolation • Stray light correction • Using laser scan data (if available) • Otherwise use parameterization • Total ozone and SO2 calculation • “Spikes” correction • HG control • Use same process describe above for total ozone • Angular response correction

  28. Application of New BDMS Software • Currently only Canadian data is processed every 4 to 6 months • Looking into processing UV data for other countries • Not currently available for public use due to lack of good user interface and installation package • Intention exists to make it widely available

  29. CBSN as an Example for the Regional Networking of Brewer Stations in the GAW Network • CBSN is an example of how a Brewer Network might be operated with minimal resources • Best to get input from other Brewer networks and scientists and recommend a set of “minimal requirements” for proper Brewer operation and a set of “optimal requirements” • These recommendations may then be forwarded to the Brewer Ad-Hoc Committee and the WMO to act as a guide for others and be tailored to their own resource situation

  30. New Developments for WOUDC • New Web Address: http:///www.woudc.org • New Web Form: http://www.woudc.org/data/MetaQuery/metaquery_e.cfm • Allows users to sub search on what data are available from the WOUDC archive • Calibrations • It has become an important issue to have data originators include calibration information, inter-comparison details and summaries and any reports dealing with the status of instruments • It is important to have this information sent to the WOUDC • The archive is designed to accommodate and report on this information • WOUDC News • The Czech Dobson and Brewer analysis programs are being successfully used by several data originators (contributors) to the WOUDC archive

  31. New Developments for WOUDC/BDMS • New Web site • WOUDC web site has undergone recent changes and so will the BDMS portion of the site • Changes are expected to be completed by late summer 2003. • Meeting reports • Will continue to post meeting reports from Biennial Brewer meetings • Hopefully can add reports from inter-comparisons. • Bulletin board for Brewer community • BDMS web site may also used as a Brewer community “bulletin board” for information such as standard operating procedures, best practises, lessons learned, even FAQs about networks and operations. • Ad hoc reports • Reports from the Brewer Sub-committee will be posted at this site

More Related