Sea Surface Temperature Changes Over the Twentieth and Twenty-First Centuries in East Vietnam Sea Simulated by Multi CMIP5 Models

The East ​​Vietnam Sea plays important roles in the Pacific Northwest region. The projection of changes in sea surface temperature (SST) in these regions is an important research topic in marine science. However, this is a very difficult problem due to the lack of available long-term projection data. Recently, with the development of numerical modeling technology, it has become an important way to help us understand climate change. This paper focuses on studying the SST changes in the East Vietnam Sea during the history of the 20th century and the change under 3 emission scenarios in the 21st century based on a combination of 20 global models (GCM) from Phase 5 of the the Climate Model Intercomparison Project (CMIP5) and together with the observed data set. Compared with the observed data, most of the global GCMs models can simulate well the spatial and seasonal changes of the SST over the East Vietnam Sea regions. The spatial and annual SST trends over the the 20th century based on both observations and multimodel ensemble averages show that the warming trend of SST over most of the East Vietnam Sea with the largest warming trend occurred in the center and southern regions of the East Vietnam Sea. However, compared with the observation, CMIP5 underestimated SST trends over most regions of East Vietnam Sea. In addition, there is a consistency between the CMIP5 and the spatial and seasonal observations of the SST trend in the East Vietnam Sea areas. The future SST projections for East Vietnam Sea indicate that RCP 4.5 and RCP 8.5 exhibit a gradual increase in annual SST during the 21st century at a rate of 0.1 °C and 0.3 °C per 10 years respectively. The lowest emission mitigation scenario, RCP 2.6, produces the lowest rate of warming. By the end of the 21st century, the annual SST is projected to increase by 0.5-2.0 °C in 3 emission scenarios of typical representative concentration pathways (RCP) 8.5, 4.5 and 2.6.