Upwelling adalah proses naiknya massa air laut dari lapisan bawah ke permukaan akibat perbedaan tekanan permukaan. Terjadi proses upwelling akan meningkatkan kesuburan perairan karena massa air di lapisan dalam naik ke permukaan yang kaya nutrisi yang dibutuhkan fitoplankton untuk berkembang. Luas sebaran daerah upwelling (radius deformasi) akan menentukan dampak proses upwelling di perairan. Penelitian ini bertujuan untuk menganalisis proses upwelling dan radius deformasi dari data satelit sensor termal. Data yang digunakan adalah data satelit termal harian dan rata-rata bulanan selama tahun 2014-2018. Data dari buoy Argo digunakan untuk memvalidasi data satelit dan menghitung radius deformasi upwelling. Analisis statistik seperti korelasi, Root Mean Square Error (RMSE), bias, dan standar deviasi digunakan untuk menguji keakuratan perkiraan data Suhu Permukaan Laut (SPL) dari satelit. Data perhitungan radius deformasi dari Argo menunjukkan bahwa pada musim timur terjadi upwelling, SPL berkisaran antara 24-26ºC, normalnya berkisaran antara 27-29ºC. Korelasi antara SPL dari data satelit dan data SPL dari Argo adalah 0,92, nilai RMSE 0,0236, bias 0,017, dan standar deviasi 0,287. Koefisien korelasi antara radius deformasi dari data in situ dan data satelit yang dihitung tinggi (r=0,9) menunjukkan bahwa citra satelit dapat digunakan untuk menentukan radius deformasi.Upwelling is the process of seawater mass rising from the lower layers to the surface due to surface pressure differences. The upwelling process will increase the fertility of the waters because the water mass in the deep layer rises to the surface which is rich in nutrients needed by phytoplankton to grow. The extent of the upwelling area (deformation radius) will determine the impact of the upwelling process in the waters. This research aims to analyze the upwelling process and deformation radius from thermal sensor satellite data. The data used were daily thermal satellite data and monthly averages during 2014-2018. Data from the Argo buoy was used to validate the satellite data and calculate the upwelling deformation radius. Statistical analyses such as correlation, Root Mean Square Error (RMSE), bias, and standard deviation were applied to test the accuracy of the satellite estimation of the Sea Surface Temperature (SST) data. Deformation radius calculation data from Argo showed that in the eastern season of upwelling, the SST ranged between 24 to 26ºC, otherwise normally it ranged between 27 to 29ºC. The correlation between SPL from satellite data and SPL data from Argo is 0.92, the RMSE value was 0.0236, the bias was 0.017, and the standard deviation was 0.287. The correlation coefficient between the deformation radius from in situ data and satellite data was calculated to be high (r=0.9), indicating that satellite imagery can be used to determine the deformation radius
