[ACG37-P04] Diurnal cycle of the wind direction and its seasonality at Manila for the late 19th century
Keywords:wind direction, diurnal cycle, seasonality, Manila, late 19th century, data rescue
We mainly used the three-hourly wind direction and force, excluding 3 a.m. and 12 p.m. at local time, which were observed at Manila Observatory from January of 1868 to June of 1883. To clarify the characteristics on diurnal cycle and its seasonality, we calculated three-hourly wind direction frequency for May–October, November–January and February–April. When the wind force was zero, we counted as calm in the wind direction frequency.
As a result, calm and westerly wind were most frequently observed from 9 p.m. to 6 a.m. and at 12 a.m., respectively, throughout the year. Westerly wind during daytime hours corresponds to the sea breeze around the Manila Bay. For May–October, the sea breeze and the southwest monsoon were most frequently observed around noon and the early-evening, respectively. For November–April, easterly and southeasterly winds, which correspond to the trade wind and the land breeze, prevailed from 3 p.m. to 9 p.m. For February–April, the winds from west-south quadrant were scarcely observed. We will compare these characteristics on the diurnal cycle of the wind direction and seasonality to those for the late 20th century.
Acknowledgements: This research was supported in part by JSPS KAKENHI Grant-in-Aid for Scientific Research of the MEXT 15K16283 and 26220202.