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Asia-Pacific Network for Global Change Research

Asia-Pacific Network for Global Change Research

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Presentation

Comparison of coral bleaching hotspot mapping in Southeast Asia (Thailand, Cambodia and Vietnam) based on sea surface temperature modelling by National Oceanic and Atmospheric Administration Coral Reef Watch before and during Covid-19 Pandemic

Due to Covid-19 pandemic in the year 2020, international travel and hence the tourism was down by more than 95% globally. The influx of tourism has been regarded as one of the reasons for coral bleaching. In this study, an attempt has been made to compare the coral bleaching hotspot (CBH) mapping in the year 2019 (pre-pandemic) and 2020 (during the pandemic) based on sea surface temperature (SST) modelled data by National Oceanic and Atmospheric Administration Coral Reef Watch (NOAA-CRF). The NOAA 7-day maximum SST database is compared for the Coral Triangle region – with a focus on the Gulf of Thailand and South China sea covering Thailand, Cambodia and Viet Nam in Southeast Asia – for the first day of the month in Jan, Mar, June, Sept, and Nov both in 2019 and 2020. The CBH is taken as the measure of the difference between observed SST and monthly maximum mean temperature and was measured in the range 0 to 5 °C. No visual (< 0 °C) CBH was observed in the region for the month of January and March pre-pandemic and during the pandemic. In the month of May, CBH (1 – 2 °C) was dominant in the Gulf of Thailand covering mostly Thailand and Cambodia and was higher during the pre-pandemic period. During July, CBH (1 – 2 °C) was dominant in the south China sea covering Viet Nam and was also higher during the pre-pandemic period. Surprisingly, CBH was higher during the pandemic along Viet Nam in the South China sea, the reason of which is still a matter of further investigation. In general, with an exception in September 2020, CBH was higher during the pre-pandemic period. A detailed study covering daily, and monthly average SST would provide a better understanding of the impact of the COVID-19 pandemic on CBH.