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The modernized Swedish radiation network

The modernized Swedish radiation network. Thomas Carlund Swedish Meteorological & Hydrological Institute, SMHI. thomas.carlund@smhi.se. IPC-X 26/9 – 14/10 2005, PMOD/WRC Davos, Switzerland. The current solar radiation network of SMHI 12 stations since 1983

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The modernized Swedish radiation network

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  1. The modernized Swedish radiation network Thomas CarlundSwedish Meteorological & Hydrological Institute, SMHI. thomas.carlund@smhi.se IPC-X 26/9 – 14/10 2005, PMOD/WRC Davos, Switzerland.

  2. The current solar radiation network of SMHI • 12 stations since 1983 • Direct, global irradiance and sunshine duration measured • Diffuse irradiance calculated • Max time resolution: 6 minute averages/totals • Temp, RH, wind dir. and wind speed at all stations in the beginning • Missing: Longwave, diffuse, AOD, ...

  3. Borlänge SMHI solar radiation stations Växjö

  4. The main station at SMHI, Norrköping.

  5. The modernized radiation network of SMHI 14 stations in total 3 ”Well-equipped” stations 9 Simple stations 2 Simple stations with longwave

  6. Well-equipped station Data logging Logger Agilent 34970A, PC Sampling 1 PLC, 0.5 Hz Time resolution 1-minute mean, std Measurement Instrument Direct irradiance K&Z CH1 Diffuse irradiance K&Z CM21 Global irradiance K&Z CM21 Longwave irradiance K&Z CG4 Spectral transmission/AOD @ 368, 412, 500, 862 nm PMOD PFR-N Sunshine duration K&Z CH1 and CSD2 Air pressure Vaisala PTB220 (A) Air temperature Pentronic Pt100 (A/5) Relative humidity Vaisala HMP45DX Others Suntracker K&Z 2AP GD Ventilator SMHI-2

  7. Simple stations At 9 stations there will be: Measurement Instrument Global irradiance K&Z CM21 Sunshine duration K&Z CSD2 Air temperature Pentronic Pt100 (A/5) Relative humidity Vaisala HMP45DX Others Ventilator SMHI-2 At 2 stations there will also be: Longwave irradiance K&Z CG4 Data logging Logger Vaisala QML201A Sampling 1 Hz Time resolution 1-minute mean

  8. Logger accuracy Well-equipped station Agilent 34970A (@99% conf lev.) 0 - 10 mV: < ±7 µV  ≈ ± 0.7 Wm-2 Thermistor: 0.08 K Pt100: 0.06 K Simple station Vaisala QML201A, with factory calibration (? Conf lev.) 0 - 10 mV: < ±10 µV  ≈± 1.0 Wm-2 Pt100 @ 0 °C: < ±0.06 °C Pt100 -35 °C to +50 °C: < ±0.12 °C

  9. Calibration Well-equipped stations Radiation instruments calibrated on site against travelling references. Simple stations Radiation instruments will be calibratedat the reference station in Norrköping andthen circulated in the network.

  10. MaintenanceAccurate radiation measurements need daily maintenance.The daily mantenance will be made…

  11. … 3 days per week.

  12. Data collection Data will be collected once every hour Well-equipped stations: Files are transferred via ftp. Station clock is set against NTP server. Simple stations: The stations are called by SMHIs central data collection system ADAC. Station clock is checked and set (if needed) by ADAC.

  13. Ventilation of pyranometers (and pyrgeometers)

  14. Cont. Ventilation of pyranometers (and pyrgeometers)

  15. Cont. Ventilation of pyranometers (and pyrgeometers)

  16. Cont. Ventilation of pyranometers (and pyrgeometers) Daytime offset Cloudy sky Wind: 4-9 m/s Clear sky Wind: 1-3 m/s Clear sky Wind: 1-3 m/s

  17. Remaining work • Install the new equippment at existing and new stations • Finalize data collection routines • New calibration programs • Develop and implement new Quality control and Quality assurance procedures • Compare old and new measurements • Reporting

  18. To summarize… • Anticipated improvements in the modernized Swedish radiation network • New measurements: Longwave – 5 stations Diffuse – 3 stations AOD – 3 stations • New stations: Mountain site and Maritime site • Higher time resolution • Partly improved measurements • Improved maintenance at many sites • Improved quality control • Simplified data access

  19. Changes for the worse andwhat we won’t achieve • Strongly reduced number of direct irradiance stations, 12 → 3. • Less accurate sunshine duration measurements • No albedo or radiation balance measurements • No BSRN station (yet)

  20. Finally,We still hope the modernization will cause only a small discontinuity in our time series and that we will be able to quantify the difference between the old and new measurements.

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