Abstract
Western Java area has been numerically investigated using PSU-NCAR MM5. Mesoscale numerical simulation was performed under the synoptic scale meteorology by ECMWF data with a resolution of 0.50 × 0.50. Five days long simulation on 4-9 March 2001 was carried out. During this period, the quite strong sea breeze developed on 5 and 6 March. On March 6, 2001, at 1300 LST, the sea breeze penetrated to around 20 km from the coast of Jakarta. In this season, over Java area a synoptic scale convergence line is formed by WSW and NW winds. This synoptic WSW wind blowing over Java tends to prohibit inlandward advancement of the sea breeze. Depth of the sea breeze, on 6 Mar 2001 at 1200, 1300, 1400, and 1500 LST was 0.5, 0.8, 0.4, and 0.2 km, respectively; because of subsidence behind the convergence line by the synoptic WSW wind and the sea breeze from Java sea, upper part of the sea breeze layer was warmed after 1500 LST and thus the depth of the sea breeze was suppressed. Predicted near-surface wind at 4-9 March 2001 appears dominantly with westerly wind. In mountain area, wind direction was affected by a mountain wave. Highpressure system tends to be formed to the northeast of the Sunda street because of the topography. Then this highpressure system in turn generates dry stable layer over Jakarta at 2, 000-4, 000 m height and may suppress vertical diffusion of pollutants over Jakarta.
