This document summarizes a study that assessed meteorological drought hazards in Thailand's eastern region. The study analyzed historical precipitation data to calculate standardized precipitation indices (SPI) and simulate drought characteristics like duration, events, intensity and severity. Results showed medium to high drought hazard levels in certain provinces in May 2015. Analysis of drought characteristics from 1960-2000s found a slight increase over time.

1. Meteorological Drought Hazard Assessment
for Agricultural Area in Eastern Region of Thailand
1 Department of Civil Engineering, Faculty of Engineering at Sriracha, Kasetsart University Sriracha Campus,
Chonburi, THAILAND
2 Water Engineering and Management, School of Engineering and Technology, Asian Institute of Technology,
Pathumthani, THAILAND
*Corresponding author; E-mail address: thanasit@eng.src.ku.ac.th
Thanasit Promping1 and Tawatchai Tingsanchali1,2
1

2. 2
Introduction
Objective
Study Area
Methodology
Results and discussion
Conclusions
Outline

3. Introduction
3
Climate change around the world is caused by natural and by human activity changing.
IPCC (2019) reported an increase of 1.5°C to 2°C on average observed temperature at
present due to global warming
The changing of water cycle and meteorological phenomenon has effects on both
precipitation and temperature.
About 26 billion baht of on-season and off-season agricultural product was lost because
of severe drought in 2020.
Paddy field in 2017 covered about 18% of Thailand area or approximate 9.38 million
hectares that yields rice products to 25.24 million ton
Field crops and fruits (cassava, maize, sugar cane, pineapple and durian) are also main
agricultural products of Thailand. All of crops require a lot of water resources for
cultivation.

4. Objective
4
The main objective of this study is to simulate meteorological drought hazard based on past
precipitation data.
The sub-objectives of this study :
 The evaluation of standardized precipitation index (SPI) from historical daily
precipitation data for the 4 timesteps namely; 1960s (1951-1970); 1980s (1971-1990);
2000s (1991-2010) and 2020s (2011-2017).
 The theory of run is applied to evaluate drought parameters; duration (DD), drought
event (DE), drought intensity (DI) and drought severity (DS) based on the SPI values.

5. Study Area
5
The eastern region (ER) of Thailand with a total area of 36,502
kilometer is bounded by the Middle and Northeast region of
Thailand and the Banthat Mountain Range along the boundary
between Thailand and Cambodia. The Bangpakong, Chanthaburi
and Welu rivers located in north to south directions drain into
the Gulf of Thailand.
Figure: The Study Area in Eastern Region of Thailand

6. Methodology
6
DD DE
DS
DI

7. Result and Discussion
Estimated Standardized Precipitation Index
7
SPI-1
SPI-3
SPI-6
Figure: SPI-1, -3 and -6 (upper, middle and lower) at Prachin
Buri Meteorological Station.
Table: The average SPI Value in 1960s, 1980s, 2000s and 2020s
at Prachin Buri Meteorological Station.

8. Objective
Result and Discussion
Simulation Drought Hazard Maps
8
The drought hazard in May 2015 has very high
level at Sa Kaeo, Chachoengsao and Chon Buri
provinces and low hazard level in some parts of
Rayong, Chantha Buri and Trat provinces. The hazard
levels are classified into five levels and the area
percentages were found to be very low (0.05%); low
(12.80%); medium (49.11%); high (29.31%) and very
high (8.70%).
Figure: Meteorological Drought Hazard Map for SPI-1
in May 2015

9. Objective
Evaluation of Drought Characteristics
Result and Discussion
9
Figure: Drought Duration (DD) of SPI-1

10. Objective
Evaluation of Drought Characteristic
Result and Discussion
10
Figure: Drought Event (DE) of SPI-1

11. Objective
Evaluation of Drought Characteristic
Result and Discussion
11
Figure: Drought Intensity (DI) of SPI-1

12. Objective
Evaluation of Drought Characteristic
Result and Discussion
12
Figure: Drought Severity (DS) of SPI-1

13. Conclusion
13
The drought hazard in May 2015 has very high level at Sa Kaeo, Chachoengsao
and Chon Buri provinces and low hazard level in some parts of Rayong,
Chantha Buri and Trat provinces.
The hazard levels are classified into five levels and the area percentages were
found to be very low (0.05%); low (12.80%); medium (49.11%); high (29.31%)
and very high (8.70%).
The changing in drought characteristics is slightly increased and the hazard
level from 1.90 to 2.06 months (DD); 54 to 59 events (DE); -1.31 to -1.50 (DS); -
0.66 to -0.72 (DI) between the year periods 1960s and 2000s.