17:15 〜 18:30
[MZZ47-P01] Seasonal and Diurnal Variation of Offshore Winds in the Maritime Continent
キーワード：offshore winds, the Maritime Continent, Indonesian seas , monsoon, diurnally varying wind
We investigate the offshore wind fields in the Maritime Continent using the satellite scatterometer and atmospheric reanalysis data. This study reveals the previously unknown structures in the time-averaged of surface wind fields which can be used as consideration for offshore wind energy planning. The Maritime Continent are consisted of many islands with complex topography, and small seas connected to straits. Thus, it is a challenge to understand the distributions and variabilities of offshore wind fields. We obtained the scatterometer data from QuikSCAT Level 2B Ocean Wind Vectors for 1999–2009 and ASCAT onboard MetOP-A and MetOP-B satellites for 2010–2018 with the swath at 12.5 km pixel resolution providing the observational evidence of surface winds. The ERA5 reanalysis data of hourly surface wind for 2003–2018 at a spatial grid of 0.25° allow us to investigate the winds from the seasonal to diurnal variations. We investigate the wind divergence and curl by using those datasets. This study can serve as a basis for further studies of offshore wind resources by focusing on the detailed wind structure in the small seas and straits of the Maritime Continent or the Indonesian seas. The following results are obtained.
In the Indonesian seas, the wind divergence varies seasonally and diurnally, while the wind curl does not show a clear diurnal cycle. Along the center of the monsoon route extending from the Karimata Strait to the Arafura Sea, the wind divergence occurs from May to October with the highest magnitude in August, following the peak of the Australian winter monsoon. The wind convergence predominantly occurs in the morning time from January to December. During the night time, wind convergence mainly occurs, except in the Karimata Strait and the northern Java Sea that at the same time, the wind divergence occurs. We detect the persistent wind jet from the Arafura Sea to the Java Sea from the wind curl fields. However, the wind jet is not detected in the Karimata Strait, while this strait is the main monsoon route. The wind jet is more prominent during the Australian winter monsoon than the East Asian winter monsoon.
In the Indonesian seas, the wind divergence varies seasonally and diurnally, while the wind curl does not show a clear diurnal cycle. Along the center of the monsoon route extending from the Karimata Strait to the Arafura Sea, the wind divergence occurs from May to October with the highest magnitude in August, following the peak of the Australian winter monsoon. The wind convergence predominantly occurs in the morning time from January to December. During the night time, wind convergence mainly occurs, except in the Karimata Strait and the northern Java Sea that at the same time, the wind divergence occurs. We detect the persistent wind jet from the Arafura Sea to the Java Sea from the wind curl fields. However, the wind jet is not detected in the Karimata Strait, while this strait is the main monsoon route. The wind jet is more prominent during the Australian winter monsoon than the East Asian winter monsoon.