Database for Coastal Environment

     There are well documents that high SST (exceeding 31°C) for long period can cause the coral bleaching. The SST monitoring shows (Fig.1) that the central of Bay of Bengal and the Andaman Sea is recently dominated by abnormally warm water, with SST over 31°C . Some regions (especially in the Andaman Sea) are shown to have extreme SST exceeding 32°C.  The extreme SST is well observed by the buoy at (90E, 12N), which is one component of RAMA array developed under the coordination of CLIVAR-GOOS Indian Ocean Panel. It shows (Fig.2) that the SST at the buoy site reaches its peak in Apr. 2010 and is significantly higher than that in years 2008 and 2009. This high SST is one consequence of the late monsoon onset over Bay of Bengal and Andaman Sea. Monsoon normally onsets around the mid-April. But year 2010 did not see the onset in the end of April. The high thermal pressure by the anomalous high SST could be the main cause of coral bleaching in Andaman Sea.  The PMBC survey has revealed that the off-shore and near-shore water exceeded 31°C, which is the critical point of coral bleaching. This situation expects to occur also in Myanmar as well as probably in Malaysia.

     UNECO/IOC-WESTPAC is conducting one regional project titled Monsoon Onset Monitoring and its Social and Ecosystem Impacts (MOMSEI) under its SeaGOOS framework. MOMSEI project aims to enhance the observation capability in the Bay of Bengal and Andaman Sea region so as to understand the monsoon onset activities in the Southeastern Asia. It is expected that one monitoring buoy will be deployed in the Andaman Sea. This MOMSEI buoy, together with the RAMA buoys, will significantly improve the regional capability of ocean monitoring in the SeaGOOS region. The monsoon related drought/flood and coral reef bleaching are two top priorities within MOMSEI. It is anticipated that MOMSEI will aid to give a better risk monitoring and assessment on the regional coral reef bleaching events.

Figure 1. Five-day averaged SST over 24-28 Apr. 2010, illustrating the dominant thermal impact in the central Bay of Bengal and Andaman Sea

Figure 2. Time series of the daily SST observed by Buoy in central Bay of Bengal, particularly at (90E, 12N), from 1 Jan. 2008 to 29 Apr. 2010, illustrating the extremely high SST (over 32°C) during Apr. 2010

Figures 3a-b. The SST in Andaman Sea of Thailand was found exceeding the 31°C, which is a critical point of coral bleaching. (a) Maiton Island (southwest of Phuket Island)  (b) south of Phuket, PMBC.