STUDY OF UPWELLING STRENGTH IN SOUTHERN COAST OF SUMBAWA USING THE TEMPERATURE INDEX AND BAKUN INDEX

• Main Author: Muhammad Winant, Fachri
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/27044
• Institution: Institut Teknologi Bandung

This study aims to investigate upwelling variability based on the indicator and the index, which is calculated using ocean surface temperature and wind data. The calculation of the upwelling index (UI) in this study was carried out using two methods, i.e. the Bakun method and the method of surface temperature difference between coastal waters and offshore, which known as the coastal upwelling index (CUI). Coastal waters in this case are waters that are 50 km, 75 km, and 100 km from the coastline, while offshore has a distance of 450 km from the coastline. Coastal upwelling index for 13 years (2003-2015) was calculated using sea surface temperature data, which is obtained from the National Oceanic and Atmospheric Administration (NOAA) of the United States. Meanwhile, the calculation of the Bakun’s upwelling index for 16 years (2000-2015) was carried out using wind data from the European Center for Medium-Range Weather Forecast (ECMWF). Furthermore, upwelling indicators, i.e. chlorophyll-a abundance and vertical profile temperature data, were also utilized. The both data were obtained respectively from the website of the National Aeronautics and Space Administration (NASA) and environmental monitoring report published by Newmount Nusa Tenggara. Results of this study indicate that UI and CUI has a significant correlation to indicators of upwelling, which occured in the southern Sumbawa waters. When upwelling is occuring in the southern Sumbawa waters, chlorophyll-a abundance will increase and the 20 oC temperature contour depth on the vertical profile will get shallow. The occurrence of upwelling is also indicated by positive values of UI. Larger positive value of UI can also indicate strong upwelling is occuring, therefore UI can describe upwelling variability. Meanwhile, the CUI value does not increase along with the increase in the upwelling indicator values. The results of the phase difference analysis (time lag analysis) show an increase in the CUI values is occurring in 2 months after the upwelling indicator marked the occurrence of upwelling. The results of this study also show that variance of UI and CUI can represent variability of upwelling, that occurs in the southern Sumbawa waters during east monsoon periods (in June, July and August). UI and CUI in this study were calculated for 13 years, from years 2003 to 2015.