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Cloudnet Observing Stations

Cloudnet Observing Stations. Instrumentation C L Wrench. Cloudnet Final Symposium – 12 October 2005. Cloud Remote Sensing Stations. Cloudnet started with three cloud observing stations: Cabauw, The Netherlands [51.971N, 4.927E] Chilbolton, United Kingdom [51.145N, 1.437W]

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Cloudnet Observing Stations

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  1. Cloudnet Observing Stations Instrumentation C L Wrench Cloudnet Final Symposium – 12 October 2005

  2. Cloud Remote Sensing Stations • Cloudnet started with three cloud • observing stations: • Cabauw, The Netherlands • [51.971N, 4.927E] • Chilbolton, United Kingdom • [51.145N, 1.437W] • SIRTA-Palaiseau, France • [48.713N, 2.204E] Each CRS station had been developed over a number of years prior to 2001 with national funding. The instrumentation available at each site was different. Cloudnet Final Symposium – 12 October 2005

  3. CRS - CABAUW View from the 213m tower towards the remote sensing site Cabauw is operated by KNMI; it is located in the western part of the Netherlands and it is 0.7m below sea-level. Surface elevation changes by no more than a few metres over 20km. The surrounding region is mainly agricultural. Cesar Measurements made using the following remote sensing systems at Cabauw have contributed to Cloudnet: Additional observations made within 100km of Cabauw with: • 35 GHz cloud radar (KNMI) • 3.3 GHz FMCW radar (TARA) (TUD) • 905 nm lidar ceilometer (CT75K) (KNMI) • 22 channel mwave radiometer (MICCY) (UBonn) • Total Sky Imager (TSI-440) (KNMI) • Ceilometers (CT12K, LD-40) • Sky infrared temperature Cloudnet Final Symposium – 12 October 2005

  4. C R R A F CRS - CHILBOLTON View of the cloud radars and lidars with the 25m antenna behind Chilbolton is operated by CCLRC-RAL; it is located in Southern England and it is 84m above sea-level. Surface elevation changes by 240m over 20km. The surrounding region is mainly agricultural downland with some wooded and residential areas. Measurements made using the following remote sensing systems at Chilbolton have contributed to Cloudnet: Additional observations made at Chilbolton with: • 35 GHz cloud radar (Copernicus) • 94 GHz cloud radar (Galileo) • 905 nm lidar ceilometer (CT75K) • 3 channel mwave radiometer • 355 nm Raman lidar • 3 GHz radar (CAMRa) • Visible sky camera Cloudnet Final Symposium – 12 October 2005

  5. CRS - SIRTA SIRTA remote sensing site at Palaiseau Palaiseau is operated by IPSL; it is located in a suburban community on a plateau 20km south of Paris, and it is ~160m above sea-level. The plateau is semi-urban divided equally between agricultural fields, wooded and housing/industrial areas Measurements made using the following remote sensing systems at SIRTA have contributed to Cloudnet: Additional observations made at SIRTA with: • 95 GHz cloud radar (RASTA) • 1064/532 nm polarimetric lidar • Ceilometer (LD-40) • 2 channel mwave radiometer • (DRAKKAR) • Surface flux station (pyrheliometer/ • pyranometer/pyrgeometer) • Sun-photometer • Radiosonde launches • Sonic anemometers (10 + 30 m) Cloudnet Final Symposium – 12 October 2005

  6. Data from additional CRS-stations Distribution of DOE-ARM sites providing data to Cloudnet Cloudnet processing algorithms have been applied to data sets collected at additional sites. These include: DWD-Lindenberg (Germany) ARM-SGP (Oklahoma) ARM-TWP (Manus) ARM-TWP (Nauru) ARM-NSA (Barrow) All of the additional sites contain a 35 GHz cloud radar, a ceilometer and a multi-frequency microwave radiometer. Cloudnet Final Symposium – 12 October 2005

  7. Cloudnet achievements • Meeting objectives set at the beginning of the Cloudnet project: • Operate the stations for a minimum of one week per month for two years • Achievements: • Operations at all sites started in October 2002 • Successfully demonstrated an ability to make long term unattended • observations with three key remote sensing instruments: • Cloud radars / Backscatter lidars / Microwave radiometers Cloudnet Final Symposium – 12 October 2005

  8. Radar Data for Cloudnet Cloudnet Final Symposium – 12 October 2005

  9. Lidar data for Cloudnet Cloudnet Final Symposium – 12 October 2005

  10. mwave radiometer data for Cloudnet Cloudnet Final Symposium – 12 October 2005

  11. Cloudnet achievements • Meeting objectives set at the beginning of the Cloudnet project: • Operate the stations for a minimum of one week per month for two years • Achievements: • Operations started in October 2002 – see data summary tables • Successfully demonstrated an ability to make long term unattended • observations with three key remote sensing instruments: • Cloud radars / Backscatter lidars / Microwave radiometers • Successful cross-calibration of the three cloud radars was achieved • by RASTA being operated at Chilbolton and Cabauw Cloudnet Final Symposium – 12 October 2005

  12. Cloudnet achievements • Meeting objectives set at the beginning of the Cloudnet project: • Operate the stations for a minimum of one week per month for two years • Achievements: • Operations started in October 2002 – see data summary tables • Successfully demonstrated an ability to make long term unattended • observations with three key remote sensing instruments: • Cloud radars / Backscatter lidars / Microwave radiometers • Successful cross-calibration of the three cloud radars was achieved • by RASTA being operated at Chilbolton and Cabauw • Investigated the lifetime and reliability of the cloud radar amplifiers Cloudnet Final Symposium – 12 October 2005

  13. Experiences with 94 GHz Cloud Radar amplifiers The Extended Interaction Klystron Amplifier (EIKA) in the 94 GHz GALILEO radar at Chilbolton operated for 3 years losing 20dB of Tx power before it failed in March 2002. Plot of Z measured using GALILEO in rain illustrates how the power declined with time A replacement EIKA for GALILEO was acquired in April 2003 – it ran for 12 months continuously before it lost 10dB of Tx power. This is in line with similar losses experienced by the EIKA in RASTA Design modifications to the cathode and its operating temperature are being implemented by the manufacturer Cloudnet Final Symposium – 12 October 2005

  14. Experiences with 35 GHz Cloud Radar amplifiers The output power of the 35 GHz travelling wave tube (TWT) that is used in the cloud radar at Cabauw has gradually decreased with time. In August 2001 the output power was approximately 90 W, it had decreased to 20 W by the end of 2004. This was more than expected for a TWT operated continuously for 4 years. The output power from the 35GHz EIKA used in the COPERNICUS radar at Chilbolton has remained high after 22 months of operation. There has been a 1.5dB fall in gain after 16,000 hours. Can cope with another ~12dB loss in gain Cloudnet Final Symposium – 12 October 2005

  15. Cloudnet achievements • Meeting objectives set at the beginning of the Cloudnet project: • Operate the stations for a minimum of one week per month for two years • Achievements: • Operations started in October 2002 • Successfully demonstrated an ability to make long term unattended • observations with three key remote sensing instruments: • Cloud radars / Backscatter lidars / Microwave radiometers • Successful cross-calibration of the three cloud radars was achieved • by RASTA being operated at Chilbolton and Cabauw • Investigated the lifetime and reliability of the 94GHz radar amplifier • Development of new techniques for auto-calibration of cloud radars • and cloud lidars – subject of next talk (Ewan O’Connor) Cloudnet Final Symposium – 12 October 2005

  16. Cloudnet achievements (cont) • Measurements – data handling • Processed data collected during the project has been archived at the University of Reading • Objective categorisation of radar and lidar targets • – subject of later talk (Robin Hogan) • Development of a technique to improve estimation of LWP from • mwave radiometers by use of ceilometer data • Archived the model forecast data over each of the sites • Data from seven operational forecast models were archived at the • University of Reading for each of the CRS stations Cloudnet Final Symposium – 12 October 2005

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