The primary research goal of the Basler Stadtklima Projekt (BASTA, funded by the Swiss National Foundation) is to investigate properties of turbulent flow in the urban canopy layer. Furtheron, net radiation and vertical profiles of wind speed, temperature and humidity are measured continuously, for comparison with values from rural and suburban stations of the REKLIP energy balance network.
In 1993 a measurement programme was started at the building of the MCR Lab. The site is located close to the center of Basel and the surrounding area consists of building blocks with inner yards with building heights in the range of 15 to 20 m. The instruments are fixed to an 18 m high tower, which is mounted on the uppermost terrace of a five-story building. The tower base is at 15 m above street level. The measurements started with three levels, and in summer 1994 two additional levels were installed (see Table). On top of the tower at 35 m a three dimensional ultrasonic anemometer, briefly sonic, (Solent, Standard) recorded continuously with 1 Hz the wind vector and all raw data were stored.
From August, 16 to September 27, 1994, three different types of Solent sonics mounted on top of the tower were intercompared. From October 5, 1994, on two Solent sonics (Standard, 1 Hz; Enhanced, 4 Hz) including measurement of temperature fluctuations are operated at 34 and 28 m storing first and second moments on a 30 minute basis.
During July 1995 a second site has been instrumented. A 50 m antenna tower located 24 m above street level supports three sonics (Solent, Research; 21 Hz) at three heights and wind speed, temperature and humidity measurements at six heights. Additionally, a SODAR was operated close to the 50 m tower.
Online monitoring of the MCR Lab tower data was realized in December 1997.