MTP-5 AIR TEMPERATURE PROFILES BY MICROWAVE TECHNOLOGY

MTP-5 is a remote sensing instrument that measures microwave radiation emitted from the lower 1000 m of the atmosphere, within the Planetary Boundary Layer. The atmosphere is a strong source of radiation but the changes due to temperature are small. So, a very sensitive receiver is required. Unique radiometers and specially designed antennae operating in the 5 mm waveband form the heart of MTP-5 the single-channel-radiometer.

Atmospheric radiation is measured by scanning in angular steps from horizontal to vertical position. The operating software processes the data into vertical height and temperature information T(h). The data is stored and profiles are displayed graphically every 5 minutes, typically showing the temperature in 10, 25 and 50 m height intervals.

For the MTP-5 a special, very compact and robust microwave receiver has been developed. This sensor passively detects the thermal blackbody radiation of the atmosphere at a wavelength of λ = 5 mm (f = 60 GHz). The MTP-5 emits no radiation and therefore does not require a special operating permit. The device is easy to transport and can be used for mobile applications. The installation is rather simple and quick and can be done by the user after a short introduction to the device. A suitable place for the installation would be an elevated platform or a roof. The data is recorded on the PC and automatically processed by the software. Every 5 minutes, the temperature profile is calculated by specially developed algorithms and then displayed graphically. Unlike multi-channel radiometers, the MTP-5 has the great advantage of not requiring specially trained personnel, calibrating itself, and automatically generating temperature profiles in real time in all weather conditions.

Models:

MTP-5-H is the compact standard unit. It makes measurements up to 1000 m above the instrument and gives the same performance in all weather conditions. It is compact and operates from 12 VDC. The rotating scanner assembly is protected by a special cover having very good microwave transmission. The cover sheds precipitation and allows compensation for dirt during the self-calibration process. A high accuracy ambient temperature sensor is part of the self-calibrating system.

The displayed altitude resolution is 50 m and the temperature accuracy is 0.2 - 1.2°C or better (depending on type of profile). The field of view is a 2.5° cone. The only routine maintenance is the periodical cleaning of the scanner cover. MTP-5-H is ideal for use in urban environments and at airports.

MTP-5-HE (Extended range) was developed for locations where the urban/industrial area lies in a valley or close to mountains and inversions up to 1000 m can cause problems. Displayed altitude resolution is from 25 to 50 m. In order to measure to 1000 m a more sensitive and narrower bandwidth design of microwave radiometer is used and the frequency is slightly shifted to ‘see’ further in the atmosphere.

MTP-5-PE (Polar Extended range) and RE uses a similar microwave radiometer to the MTP-5-HE. However, it is designed to provide much improved altitude resolution. The displayed altitude resolution is down to 10 m in the first 100 m range. This high resolution is important for measurements over snow and ice, where temperature gradients can be very steep over small height increments. Similar effects can be observed over desert. surfaces.

Data Example