HATPRO-TOPHAT installed at Jülich

HATPRO (Humidity And Temperature PROfiler) is a passive microwave radiometer manufactured by Radiometer Physics GmbH installed at the Forschungszentrum Jülich as part of JOYCE. It measures brightness temperatures at 7 channels along the slope of the water vapor absorption line at 22 GHz and at 7 channels along the slope of the oxygen absorption complex at 60 GHz with allow the retreival of integrated water vapor (IWV), cloud liquid water path (LWP) as well as tropospheric and humidity temperature profiles.

Zenith measurements alternate with RHI towards the north and PPI scans at 30 degrees elevation. Scan patterns are partially synchronized with the neighbouring cloud radar. Additionally, regular elevation scans within provide high-quality temperature profiles in the boundary layer. Attached to the side, it also includes two broadband infrared pyrometers, sensitive to water vapor, low-LWP (< 50 gm^-2) liquid clouds as well as ice clouds. An automatic weather station complements the measurements with ambient temperature, rel. humidity, wind and precipitation observations.

• Vertically pointing observations with integration times up to 1 seconds.
• Elevation scans for boundary-layer temperature profiles.
• Full azimuth/elevation scanning capability for horizontal variability of water vapor and clouds

• Standard measurement mode is vertically pointing, 1 second integration time
• Every 15 minutes one elevation scan with following angles: 42°, 30°, 19°, 10.2°, 5.4° (duration ~100 seconds) for improved resolution of temperature profiles in lowest 1000 m above ground
• Every 30 minutes one azimuth scan at 30° elevation angle with 5° azimuth resolution (duration ~3 minutes) for horizontal variability of IWV and LWP

• Automatic relative calibrations are routinely performed
  • Automatic noise-switching for gain calibration with 50 Hz
  • System noise is calibrated every 5 minutes with view on ambient target
• Absolute calibrations using LN2 are performed every 6 months

• Automatic rain detection (data are flagged in case of rain detected by rain sensor)
• Offset corrections for liquid water path
• O-B statistics from atmospheric models for brightness temperature offset correction available
• Spectral consistency checks
• Thresholds for Level 2 data products
• Housekeeping data analysis
• Visual data inspection

The following data products are provided via the SAMD database. If you would like to have additional data or recent data that have not been uploaded to SAMD yet, please fill the data request sheet and send it to info@joyce.cloud

• Cloudnet target classification uses LWP data from HATPRO. Combined with cloud radar and ceilometer observation, clouds are characterized by their geometrical extent as well as their microphysical properties. Data are available via ACTRIS cloudnet website

Current observations at quicklook archive

Time series of brightness temperatures (left) and Integrated Water Vapor / Liquid Water Path (right)

Time series of profiles of temperature (left) and relative humidity (right)

Since 2010, TOPHAT is the standard HATPRO instrument at JOYCE. It is from the second generation (G2) of HATPRO microwave radiometers and was upgraded in 2016 to the latest receiver generation (G5).

From 2008 to 2010, SUNHAT was operated at JOYCE. It is a HATPRO of the first generation (built in 2005). FOGHAT is another Generation 5 radiometer and mainly used in measurement campaigns.

HATPRO-TOPHAT installed at Jülich with two IR Pyrometers and the automatic weather station in front