he Radiometrics Profiling Radiometer, model MP-3000A, produces vertical profiles from the surface to 10 km, producing high-resolution temperature, relative humidity and water vapor profiles, and low-resolution liquid profiles.
The MP-3000A incorporates two radio frequency (RF) subsystems in the same cabinet. These RF subsystems share the same antenna and antenna pointing system. The temperature profiling subsystem utilizes sky brightness temperature observations at selected frequencies between 51 and 59 GHz. The water vapor profiling subsystem utilizes sky brightness temperature observations at selected frequencies between 22 and 30 GHz.
Surface meteorological sensors (Met Sensors) and a rain sensor are included to measure air temperature, relative humidity and barometric pressure and rain. An internally mounted, zenith-pointed infrared thermometer (IRT) improves the measurement of water vapor and cloud liquid water density profiles using "passive technology", so it does not emit detectable radiation.
The radiometer is installed on a tripod outdoors on the roof of the Grove School of Engineering, where the instrument has a clear view of the sky, from horizon to horizon.
A computer with controlling software, located in the ORS Lab two floors below, generates real-time graphics which include:
- Met Sensor time series (level 1 data);
- Brightness Temperature time series (level 1 data);
- Temperature, Water Vapor, Liquid Water, Relative Humidity Profiles, and column integrated vapor and liquid (level 2 data);
- TIP calibration derived values of Noise Diode Temperatures;
- LN2 calibration derived values of Noise Diode Temperatures.
Liquid water on the antenna radome (also referred to as the "microwave window") can cause error in the observed brightness temperature. To minimize this error, the radiometer radome is made hydrophobic to repel liquid water, and a special blower system (the SuperBlower) is used to sweep water beads and snow away from the radome. The ambient temperature and relative humidity sensors are integrated in the inlet of the blower system to ensure a steady flow of ambient air over the sensors. The rain sensor is mounted on the top of the blower system. The ambient barometric pressure sensor is located inside the cabinet to minimize the range of sensor ambient temperature. The IRT views the sky via a replaceable low-loss cabinet window.
Microwave Radiometer Dataset Archives:
Image Profiles. Image plots of variable intensity versus time and altitude for Liquid Water, Water Vapor, Relative Humidity and Temperature; Surface Variables graphs.
Database Archive. Contains Liquid Water, Relative Humidity, Temperature, Water Vapor, and Surface variables at heights of 100m to 9800m in 100m steps. Data can be downloaded as CSV files for a selected date range.
Supporting Instrument Documentation: (Where indicated, restricted to CCNY access)
Thomas L. Rose, "A Rigorous Comparison of Microwave Profiling Radiometer Architectures: Compatibility with Future Instrument Demands", Radiometer Physics GmbH 24 April 2007.
Tim Hewison and Catherine Gaffard, "Report on Met Office Participation in Convective Storm Initiation Project (CSIP) at Linkenholt", Met Office, University of Reading, Meteorology Building, PO Box 243, Earley Gate, Reading, RG6 6BB, UK, July 13, 2016.