SURFACE HEAT FLUX ASPECT ON THE VARIABILITY OF SEA SURFACE TEMPERATURE AND CHLOROPHYLL-A ALONG THE SOUTHERN COAST OF JAVA

Husein ALFARIZI , Anindya WIRASATRIYA , Kunarso KUNARSO , Muhammad Rais ABDILLAH , Dwi HARYANTI

DOI: 10.21163/GT_2023.181.10

ABSTRACT: Indonesia as a region located in the tropics gets a greater heat distribution than the other hemisphere and has an important role in the phenomenon of atmospheric and ocean interactions in the Indo-Pacific region. The heat exchange between the ocean and the atmosphere affects the dynamics of both. The southern coast of Java is known as the upwelling area which is driven by the variability of Ekman transport and Ekman pumping. The present study aims to investigate the effect of heat flux variability on sea surface temperature variability and chlorophyll-a in surface upwelling areas along the Southern coast of Java which was less observed in the previous study. The study was conducted with a quantitative descriptive approach through climatological spatial and temporal data processing for 10 years from 2007 – 2016. The data used are Shortwave Radiation, Longwave Radiation, Latent Heat Flux, Sensible Heat Flux, Sea Surface Temperature, Chlorophyll-a, Surface Wind, and Mixed Layer Depth. The results show that the Southern coast of Java receives an average heat of 547.8 W/m2 per year. Net Heat Flux fluctuations are dominated by heat intake by Shortwave Radiation and heat release by Latent Heat Flux. Net Heat Flux has a very strong relationship with sea surface temperature with the best correlation of 0.84 and 0.83 at lag+2 and lag+3 months indicating that Net Heat Flux plays an important role in modulating changes in sea surface temperature in the next 2-3 months. A significant increase in chlorophyll-a occurred after the Net Heat Flux was positive or there was ocean heating which caused the shoaling of Mixed Layer Depth, resulting in primary productivity in the east monsoon along with nutrient rich entrainment to the surface by EMT and EPV.

Keywords: Surface Heat Flux, SST, Chlorophyll-a, Upwelling, Southern coast of Java

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