GC126-01
Small-scale features of offshore winds in the Maritime Continent
Wednesday, 16 December 2020: 11:30
Virtual
Inovasita Alifdini, Hirosaki University, Graduate School of Science and Technology, Aomori, Japan, Teruhisa Shimada, Hirosaki University, Graduate School of Science and Technology, Hirosaki, Japan and Anindya Wirasatriya, Diponegoro University, Oceanography, Semarang, Indonesia; Diponegoro University, Center for Coastal Rehabilitation and Disaster Mitigation Studies, Semarang, Indonesia
Abstract:
The small-scale features of offshore wind fields in the Maritime Continent are investigated from the scatterometer and 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 existence of many islands and small seas connected to straits in the Maritime Continent making it a challenge to understand the distributions and variabilities of surface winds. 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 rotation 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 rotation 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 amplitude in August, following the peak of the Australian monsoon. In August, the duration of wind divergence per day is longer (from 02 UTC to 21 UTC) than in other months (from 02 UTC to 17 UTC). The peak of wind divergence in the Indonesian seas are the following: at 8 UTC (October–December), 10 UTC (January–May), 12 UTC (May–June; September), and 14 UTC (July–August). In the small seas and straits, the variation in wind divergence and rotation strongly depends on the complicated land-sea contrast. The amplitude of wind divergence and rotation near the coast is higher than in the center of the seas.
