Mentor: C. Acquistapace
TOPHAT is a HATPRO passive microwave radiometer 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 temperature profiles. Zenith measurements alternate with rhi and ppi scans. Scan patterns are partially synchronized with the neighbouring cloud radar MIRA. 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.
TOPHAT (RPG HATPRO Generation 2) at Forschungszentrum Jülich on the roof of the IEK-8 (Institut für Energie- und Klimaforschung: Troposphäre).
The left figure shows the 14 channel brightness temperatures plus relative humidity (RH, top row) and temperature (second row) of the environment. On the right figure, the Integrated Water Vapor (IWV, third row) and Liquid Water Path (LWP, last row) derived from TOPHAT brightness temperatures are displayed.
|Receiver 1 (R1)||water vapor and liquid water absorption|
|Frequencies (R1) [GHz]||22.24, 23.04, 23.84, 25.44, 26.24, 27.84, 31.40|
|Channel band-widths (R1) [MHz]||230, 230, 230, 230, 230, 230, 230|
|Optical Resolution (R1) (HPBW)||3.3°-3.7°|
|Temporal Resolution||1 to 2 seconds|
|Receiver 2 (R2)||oxygen absorption|
|Frequencies (R2) [GHz]||51.26, 52.28, 53.86, 54.94, 56.66, 57.30, 58.00|
|Channel band-widths (R2)[MHz]||230, 230, 230, 230, 600, 1000, 2000|
|Optical Resolution (R2) (HPBW)||2.2°- 2.5°|
|Pointing Resolution (R2)||0.6° (elevation), 0.1° (azimuth)|
|Side-lobe level||< -30 dBc|
|Infrared pyrometers||11.1 μm, 12.0 μm, accuracy 1.0 Kelvin|
|Size||630 mm x 360 mm x 900 mm|
|Power Consumption||<120 W (350 W peak) + dew blower 130 W|