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ENSO Impact in Southern Thailand


While in Thailand, last month Peter and I met one of Kris and Mullica’s graduate students, who is involved with the regular collection of GLOBE weather data and is learning about the ENSO cycle. He and I chatted a lot about what he is doing, and he took us to see one of the automated weather stations that is situated in a mountain village about 30 minutes out of Nakhom Si Thammarat. 

We had gotten to this southern part of Thailand about a week after some very serious flooding had killed 38 people, devastated many homes and villages, and had even shut the airport down- which had only reopened the day before we flew in. I took these pictures from the airplane as we made our descent. 


 
photo credit: Dorian Janney

 
photo credit: Dorian Janney
 
Unfortunately, the flooding also caused many electricity outages to occur, and this knocked one of the automated weather stations off-line in the picturesque village of Kiriwong.  We went to the village during a rainstorm to go with Harry and several other graduate students to check the weather station and get it back up and running. 
 


photo credit: Dorian Janney

 
photo credit: Dorian Janney

I asked Harry if he could write a story about what he has learned about the impact of the current El Nino and slight La Nina patterns on the weather in southern Thailand during the past year. Here are some of the things he shared:

“Thailand is a country in the Southeast Asia located just above the Earth’s equator, surrounded with the Gulf of Thailand in the Pacific Ocean to the east, and the Andaman Sea in the Indian Ocean to the west. Every year the Intertropical Convergence Zone: ITCZ moves up and down from the equator causing three seasons in Thailand: summer from February to May, rainy season from June to September (due to the warm and moist southwest monsoon from the Indian Ocean), and winter from October to January (due to the cold and dry northeast monsoon from China). But in the southern Thailand these seasons are different. In winter, the cold and dry northeast monsoon wind which blows over the Gulf of Thailand usually brings water vapor with it (making it more humid), and while the monsoon wind enter the eastern part of the southern Thailand, large amount of water vapor condenses as heavy rainfall. These heavy rainfall usually cause the flood every winter (especially from December to January) in some parts of the southern Thailand.

The El Niño-Southern Oscillation: ENSO is a complex periodical variation in winds and Sea Surface Temperature: SST over the tropical eastern Pacific Ocean, which in turn modulates weather and climate worldwide as well as in the southern Thailand. Strength of the northeast and southwest monsoon winds were also is modulated by ENSO. During summer in 2016, there is a major El Niño event in the tropical Pacific Ocean, and it affected local weather in the southern Thailand as a major drought. There was only a little rain during that summer as well as during rainy season, and many provinces in the southern Thailand were suffered from it especially Nakhon Si Thammarat. At that time, while the drought slowly developed, people in Nakhon Si Thammarat as well as hospitals in the city have to called to the government to provide their the fresh water which must be transported from other regions because the city had no fresh water anymore. Agriculture is also affected; some kinds of food are depleted (especially rice) and need to be transported from other provinces.
After summer, the situation got better due to the first rainfall in winter, but after that it keeps raining while a La Niña event developed. Then after several days of heavy rainfall in December 2016 due to a tropical low-pressure cell powered by the northeast monsoon and strengthen by La Niña, many provinces in the southern Thailand were flooded. The situation got even worst in January 2017, when another low-pressure cell developed and stayed over the southern Thailand for so long and cause very heavy rainfall in all provinces in the southern Thailand, many of them got severe flood and landslide which destroyed many houses, cut down many bridges, roads, and railways, and also killed many people. Some airports have to close for several consecutive days, some areas got power shortage, and several government agencies have worked together in order to brought foods and supplies to victims.

 
photo credit: Harry Koad


The Center of Excellence for Ecoinformatics and School of Science, Walailak University, as an educational institute in Nakhon Si Thammarat, is currently studying the causes and tries to predict local weather and climate oscillations. Several automatic weather stations were deployed and continuously collecting weather data since more than 10 years ago. The Tourism Authority of Thailand along with the Nakhon Si Thammarat Tourism Association, have started a project with the Center of Excellence for Ecoinformatics to promote local tourism as well as monitor and provide local weather data to local communities and tourists in real time since 2013. Thanks to the technology in the age of Internet of Things, many electronic instruments are becoming smaller and cheaper, so an affordable system to monitor local weather condition in real time is possible to create.
    

We created a system to monitor local weather condition called ecocam by deploying several cameras with an automatic weather station per touristy site, then developed a program to operationally took photos every given time interval and overlaid them with weather data. These images were uploaded to a cloud storage via cellular network and displayed in a website portal: www.nakhonsiawesome.com. Ecocam is not only a real time weather monitoring system, but also a weather archive system for scientists to study and for local communities to keep track of the changes in their villages.

              
photo credit: Harry Koad

The Kiriwong village, which is one of the most popular touristy sites in Nakhon Si Thammarat, and technically an ideal place to monitor local weather associated with the flood in Nakhon Si Thammarat. Kiriwong is a gardening village with peaceful landscape located in mountain area. Each time of heavy rainfall, water level of rivers in this village will increase, and if water level reaches certain value there will probably be the flood in the city of Nakhon Si Thammarat soon. That is why the Kiriwong village was selected as one of monitor sites to deploy ecocam system. Unfortunately, there is a power shortage problem in Kiriwong during major flood in 2016-2017, which causes ecocam system to stop operating and cannot be fixed until the flood situation is back to normal. But fortunately, automatic weather station data were still being transmitted to a cloud storage, and we hope these important data will help us develop a better local weather warning system in the future. “

 

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