Height [m] 1 O O O O O o
1 3.0,0,0,0,0,0 ■
1 Température [°C]
MTP 5-H is the original member of the family. It makes measurements up to 6OO m above the instrument and gives the same performance in all weather conditions. It is compact and operates from 12 VDC (a bench-type AC-DC power supply unit is included). The rotating scanner assembly is protected by a special Teflon™ cover that has very good microwave transmission. The cover sheds precipitation and allows compensation for dirt during the self-calibration. A high accuracy ambient temperature
sensor forms part of the self-calibration system. A mounting frame is included, and cables for the temperature
sensor, power and RS 232 data communication to a PC (not included). Typically temperature inversions that cause bad air quality events occur well below 6OO m, if they are higher than this there is not normally a problem. Altitude resolution is 50 m and the temperature accuracy is ±0.5 °C or better. The field of view is a 3 ° cone. The only routine maintenance is to periodically clean the Teflon™ scanner cover. MTP 5-H is ideal for use in urban environments and at airports and operates from -40 °C to +50 °C.
MTP 5-HE was developed for locations where the urban / industrial area lies in a valley or close to mountains and inversions up to 1OOO m can cause problems. In order to measure to 1OOO 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. A consequence of this is that the altitude resolution and the temperature accuracy are not quite as good as the MTP 5-H and there is some reduction in accuracy in heavy rain or fog.
MTP 5-P (POLAR) uses the same microwave radiometer and electronics as the MTP 5-H. However, it is designed to provide much improved altitude resolution, down to 1O m in the first 1OO m range. This 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. To achieve this improved resolution a much narrower field-of-view is required, 1 ° or less. A larger capture area is therefore needed in order to maintain the signal-to-noise performance. A parabolic dish antenna has the radiometer attached directly to it and is rotated in very small angular steps. The Teflon™ cover does not rotate, therefore dirt is not compensated for and the cover must be kept clean. The housing of MTP 5-P is much larger than that of MTP 5-H and MTP 5-HE and is designed for operation in typical Polar conditions, as encountered in the Arctic and Antarctic. A température inversion, typically in the early morning, the gasses and aerosols are trapped close to the ground. Height [m] OOOOOO
0.0,0,0,0,0,0 ■ 1 Temperature [°C] During the day the profile becomes adiabatic as the gasses and aerosols escape to higher levels.
WINDOWS™ SOFTWARE runs on a PC connected to the MTP 5 and controls system configuration, measurement, data storage, processing, diagnostics and auto-calibration. The data is stored as daily ASCII files for easy export to spreadsheets. After each scan, a graph of the temperature profile is shown on-screen. Daily graphs of temperatures can also be displayed. The temperature field display and the temperature profile
