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

Cloud Remote Sensing Stations Cloudnet Final Symposium – 12 October 2005 Cloudnet started with three cloud observing stations: (1)Cabauw, The Netherlands [51.971N, 4.927E] (2)Chilbolton, United Kingdom [51.145N, 1.437W] (3)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.

CRS - CABAUW Cloudnet Final Symposium – 12 October 2005 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. Measurements made using the following remote sensing systems at Cabauw have contributed to Cloudnet: 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) Additional observations made within 100km of Cabauw with: Ceilometers (CT12K, LD-40) Sky infrared temperature Cesar

CRS - CHILBOLTON Cloudnet Final Symposium – 12 October 2005 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: 35 GHz cloud radar (Copernicus) 94 GHz cloud radar (Galileo) 905 nm lidar ceilometer (CT75K) 3 channel mwave radiometer Additional observations made at Chilbolton with: 355 nm Raman lidar 3 GHz radar (CAMRa) Visible sky camera C F A R R

CRS - SIRTA Cloudnet Final Symposium – 12 October 2005 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: 95 GHz cloud radar (RASTA) 1064/532 nm polarimetric lidar Ceilometer (LD-40) 2 channel mwave radiometer (DRAKKAR) Additional observations made at SIRTA with: Surface flux station (pyrheliometer/ pyranometer/pyrgeometer) Sun-photometer Radiosonde launches Sonic anemometers ( m)

Data from additional CRS-stations Cloudnet Final Symposium – 12 October 2005 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 achievements Cloudnet Final Symposium – 12 October 2005 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

Radar Data for Cloudnet Cloudnet Final Symposium – 12 October 2005 Instrument [Location] TypeRangeResolution Type of operation Data collected GHz [Cabauw] Coded-Pulse Doppler Co-Pol +’X-Pol’ 0.2 – 13 km adjustable 90 m adjustable Continuous8/ /2005 TARA 3.3 GHz [Cabauw] FM-CW Doppler Dual-Pol 15 km30 m Continuous10/ /2005 GALILEO 94.0 GHz [Chilbolton] Pulsed Doppler Co-Pol 16 km60 m Continuous 8/ /2002 4/ /2004 COPERNICUS GHz [Chilbolton] Coded-Pulse Doppler Dual-Pol 15 km adjustable 30 m adjustable Continuous 4/ / / /2005 RASTA 95.0 GHz [SIRTA] Pulsed Doppler Co-Pol 15 km60 m Mon-Fri (8:00-20:00) Continuous 10/2002-9/ /2003-9/2004

Lidar data for Cloudnet Cloudnet Final Symposium – 12 October 2005 Instrument [Location] TypeRangeResolution Type of operation Data collected CT75K 905 nm [Cabauw] Ceilometer 11 km30 m Continuous 9/2001-9/2005 CT75K 905 nm [Chilbolton] Ceilometer 11 km30 m Continuous 9/2001-9/2005 LNA 1064/532 nm [SIRTA] Pulsed Co-Pol+X-Pol 15 km15 m Mon – Fri (8:00 – 20:00) [Not in rain] 10/2002-9/2005 LD-40 [SIRTA] Ceilometer 6 km30 Continuous 01/ /2004

mwave radiometer data for Cloudnet Cloudnet Final Symposium – 12 October 2005 Instrument [Location] Channel Frequencies Channel BTmp resolution Type of operation Data collected MICCY [Cabauw] [22 channels] GHz GHz 90.0 GHz ~0.1 K Continuous 8/2001 – 8/2003 CMR [Chilbolton] 22.2 GHz 28.8 GHz 37.6 Ghz 0.4 KContinuous 4/ /2005 DRAKKAR [SIRTA] 23.5 GHz 36.5 GHz 0.25 K Continuous 7/ /2005

Cloudnet achievements Cloudnet Final Symposium – 12 October 2005 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 achievements Cloudnet Final Symposium – 12 October 2005 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

Experiences with 94 GHz Cloud Radar amplifiers Cloudnet Final Symposium – 12 October 2005 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 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

Experiences with 35 GHz Cloud Radar amplifiers Cloudnet Final Symposium – 12 October 2005 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 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 achievements Cloudnet Final Symposium – 12 October 2005 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 achievements (cont) Cloudnet Final Symposium – 12 October 2005 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 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