Sea surface temperature trend analysis by Mann-Kendall test and sen’s slope estimator: a study of the Hai Phong coastal area (Vietnam) for the period 1995-2020

Based on the Mann-Kendall test and Sen’s slope method, this study investigates monthly, seasonal, annual sea surface temperature (SST) trends in coastal area of Hai Phong (West Tonkin Gulf) based measurements at Hon Dau Station from 1995 to 2020. The results show a warming trend 0.02°C/year for period 1995-2020 (significant level α = 0.1) 0.093°C/year 2008-2020 0.05). monthly SSTs June September increased by 0.027°C/year 0.036°C/year, respectively, 1995-2020, 0.080°C/year 0.047°C/year, 2008-2020. SST winter, summer, other months were either different two periods or not significant enough. This may be due impact ENSO, which caused interannual variability with intrinsic mode functions (IMF) signals ~2 (IMF3) ~5.2 years cycle (IMF4). A combination these had maximum correlation 0.22 ONI (Oceanic Niño Index) delayed 8 months. ENSO events took ~8 affect variation within 1.2°C.