INTEGRATION OF SENTINEL-1A SAR, HYDRO DYNAMIC AND TRAJECTORY MODEL OF OIL SPILL AT BALONGAN COASTAL WATER JAVA SEA, INDONESIA

Abstract

Oil spill is a crucial issue for marine ecosystems, it is necessary to develop such a comprehensive and accurate oil spill detection and mitigation plan for counter measure. Balongan coastal water, Java Sea is an oil loading, unloading and refinery station. The study aims to determine the wide extent area, volume and monsoonal trajectory and volume of the oil spill in Balongan coastal water. The new paradigm of this study is the integration of 58 sets of Sentinel-1A SAR data analysis had resulted to 11 data sets confirmed with oil spill events. Then used as spatial reference, date, tide data and classification of oil spill to develop numeric trajectory modell using hydrodynamic GNOME software. The numerical trajectory modell for oil spill was running up from day-0 to 10 days or 240 hours period. Sea surface current during transition-1 April to May 2019 range 0.038-0.045 m.s-1, wind speed range 2.53-3.28 m.s-1. Sea surface current during the east monsoon of September 2019 0.191 m.s-1, wind speed 4.33 m.s-1. Sea surface current during transition-2 October to November 2019 range 0.139-0.214 m.s-1, wind speed range 3.16-4.33 m.s-1. Sea surface current during the west monsoon of December 2019 to February 2020 in the range of 0.251-0.369 m.s-1, wind speed range 2.59-4.42 m.s-1. Sea surface current and wind direction in Balongan coastal water Java Sea is predominantly to the northwest direction during the transition-1 April to May 2019 and east season September 2019. Wind and sea surface current during the transition-2 of October to November 2019 and December 2019 - February 2020 is predominantly to the southeast direction. Period of transition-1 April to May 2019 wide of oil spill range 42.80-113.40 km2 and volume range 29.95-79.38 barrel of light crude oil. During the east monsoon of September 2019 is the lowest oil spill with wide area of 23.25 km2 and smallest oil spill volume of 11.62 barrel of diesel oil. During transition-2 period October to November 2019 wide area range 65.54-78.66 km2 volume range 39.07-45.88 barrel of diesel oil and light crude oil. During the west monsoon December 2-19 to February 2020 wide area range 27.08-107.90 km2 volume range 13.54-82.37 km2 of medium crude oil, light crude oil and diesel oil. Oil spill after 5 days or 120 hours trajectory modell, wide area range of 12.10-57.07 km2, and most events during the transition-1 and the east monsoon were dispersing out after 10 days or 240 hours. Oil spill trajectory modell after 10 days or 240 hours period wide area range 19.98-144.85 km2 happened during the transition-2 November to December 2019. Evaporation rate during 10 days trajectory modell is in the range of 21.5-56.9 % after 120 hours.