Generation of an Eddy Dissipation Rate Map at the Hong Kong International Airport Based on Doppler Lidar Data

Abstract

Turbulent airflow mostly occurs at Hong Kong International Airport (HKIA) when winds blow off the hills on the Lantau Island (with peaks rising to almost 1000 m to the south of the airport) from the east to the southwest. In a previous study by Chan et al., turbulence intensity in terms of cube root of eddy dissipation rate (EDR1/3) was measured directly using a staring lidar beam. This paper extends the previous study to calculate the spatial distribution of EDR1/3 (the so-called EDR map), with the ultimate goal of monitoring the turbulence over all of the runway corridors of HKIA using the lidar. The EDR map is calculated based on plan position indicator (PPI) scans of the lidar. The whole scan area is divided into a number of small sectors, each having a size of about 1 km in range and 20° in azimuth. Velocity structure function is evaluated in every sector and compared with the theoretical von Kármán model to estimate the EDR1/3. This paper gives an overview of the calculation method, shows some examples of EDR map in terrain-disrupted turbulent airflow at HKIA, and examines the quality of the EDR1/3 value thus obtained by comparing against the measurements of a ground-based anemometer.