Application of Data Assimilation and the Relationship between ENSO and Precipitation

Sittisak Injan,Angkool Wangwongchai,Usa Humphries

doi:10.3390/mca26010024

Abstract

Climate change in Thailand is related to the El Niño and Southern Oscillation (ENSO) phenomenon, in particular drought and heavy precipitation. The data assimilation method is used to improve the accuracy of the Ensemble Intermediate Coupled Model (EICM) that simulates the sea surface temperature (SST). The four-dimensional variational (4D-Var) and three-dimensional variational (3D-Var) schemes have been used for data assimilation purposes. The simulation was performed by the model with and without data assimilation from satellite data in 2011. The result shows that the model with data assimilation is better than the model without data assimilation. The 4D-Var scheme is the best method, with a Root Mean Square Error (RMSE) of 0.492 and a Correlation Coefficient of 0.684. The relationship between precipitation in Thailand and the ENSO area in Niño 3.4 was consistent for seven months, with a correlation coefficient of −0.882.

Highlights

Relationship between El Niño and Southern Oscillation (ENSO) andIn 2011, Thailand experienced the worst flooding in its history, suffering heavy floods for a long time
An analysis of the results revealed that the assimilation of the data provided a better view of the time during the investigation and spatial error distribution
The statistics show that model errors were reduced by using satellite data for the EICMDA with 4D-Var method

Summary

Introduction

In 2011, Thailand experienced the worst flooding in its history, suffering heavy floods for a long time. The affected areas were spread around the country, but they were especially concentrated in the northern and central regions. Bangkok and its suburbs are areas that have endured heavy floods for the last 70 years. The floods have caused great damage to agricultural, industrial, economic, and social life, and they have had a high impact on other sectors. Thailand was flooded and 64 provinces were declared to be emergency disaster zones from the end of July to November 2011. There were 657 deaths, three missing people, 4,039,459 destroyed households, and 13,425,869 displaced people

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