Field Measurements About Integral Scales of Near ground Turbulence During Typhoon ‘Muifa’

Abstract:

Variation of turbulence integral scales with mean wind speed, observation height and average time interval are analyzed based on the long time field measured data recorded respectively at 10, 20 and 40 meters above the ground in Pudong New Area of Shanghai during typhoon ‘Muifa’. The results show that turbulence integral scales Lxu，Lxv and Lxw increase with mean wind speed and observation height. The ratios of the turbulence scale among the turbulence components averaged for all 10 min data are 1∶0.54∶0.07,1∶0.65∶0.11 and 1∶0.73∶0.1 respectively at 10 m, 20 m and 40 m. At the same level，both of Lxu and Lxv increase with average time interval, but Lxw almost remains constant. The correlation coefficients of the vertical scales at two levels are much lower than those of the horizontal scales.

Key words:typhoon ‘Muifa’; field measurement; turbulence integral scale; average time interval; correlation coefficient