A long-term intercomparison of windprofiler/RASS and tower measurements

Abstract

A 1290 MHz windprofiler/RASS operated continuously for more than two years close to a 200 m high meteorological tower. The comparison of the wind and temperature data at two levels, i. e. 140 and 200 m above ground level, showed a very good agreement for both wind and temperature. The standard deviation of the difference of the operationally collected hourly averaged wind data was less than 1 m/s for the 60 m range resolution of the profiler and only slightly more than 1 m/s for the 100 m range resolution. This compares favourably to results of shorter profiler-tower intercomparisons presented earlier. The standard deviation forwind direction was 11° and 16° for the 60 m and 100 m range resolution respectively. The standard deviation of the difference between the uncorrected RASS data and tower virtual temperature data was close to 0.5 K. After correction for approximations in the temperature retrieval algorithm the RASS tower intercomparison showed also the cold bias found in many RASS-radiosonde intercomparisons. An error analysis of both the tower and profiler wind data is presented. Some improvement in the quality of the profiler data can be expected by implementation of more advanced signal processing methods.

Keywords

• wind
• temperature
• rass-radiosonde
• wind- und temperaturdaten
• rass-radiosonde