9:45 AM - 10:00 AM
[AAS22-17] The analysis of the relation between non-precipitation echoes and wind structure of sea breeze
Keywords:Local circulation, Dense observation (Radar/Lidar), Numerical Simulation
Dopper lidar image (SN ratio/Doppler Velocity) depicted the sea breeze structure with landward lower flow and counter current above. The sea breeze thickness was about 1500 m at maximum and had Lobes and Cleft structures. In the lidar detectable range, two Lobe-like shapes and one gap (Cleft) between two Lobes were observed. Next, non-precipitation echoes observed by DRAW were shown rather several kilometers seaward (leeward) from the sea breeze front observed by the lidar. The distribution of non-precipitation echoes also showed vertical direction of perturbations with its flow and the echo convergence line showed gradual approach toward sea breeze front. Additionally, The non-precipitation echoes exhibited interesting relations with the sea breeze structure. In the rear of Lobes and thin Cleft structures, non-precipitation echoes distributed at lower altitudes near surface (~ 200 m) and in front of the Lobe structures was higher altitudes (~ 800 m) and convergence were detected around Cleft structures (front of Lobe - Cleft).
JMA-NHM simulation of 250 m resolution represented the above-mentioned wind structure well. The front of Lobe showed upward flow and the rear showed down flow. Surface convergence was simulated around Cleft structures. The up- and down-ward wind exhibited the horizontal circulation in Lobe structures.
In this presentation, we will show the results of observation (e.g., Lobes and Cleft structure, convergence of echoes, and vertical perturbations of echoes) and the discussion results about the relation between non-precipitation echoes distribution and wind structures focusing on pressure perturbation and thermal/mechanical structures.