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Welcome to the Thailand Drought Data Explorer!
DSI
The Drought Severity Index (DSI) is a measure of meteorological drought and its impacts on vegetation. A negative DSI indicates that an area is drier than normal whereas positive indicates that it is wetter than normal. DSI is found by calculating evapotranspiration, potential evapotranspiration and normalised difference vegetation index (NDVI) and comparing their current values to the long-term means. These datasets were sourced from MODIS TERRA satellite data.
DSI is available from February 2000 to December 2019.
Um, M J, Kim, Y, and Park, D. 2018. Evaluation and modification of the Drought Severity Index (DSI) in East Asia. Remote Sensing of Environment, 209, 66–76.
CDI JV
The Combined Drought Indicator (CDI) makes use of a combination of common indicators to identify areas that either are affected by or have the potential to be affected by agricultural drought. The method proposed by de Jager and Vogt (2015; CDI JV) has 10 levels that are determined by combinations of Standardized Precipitation Index (SPI), soil moisture anomaly and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) anomaly. As the level increases from 1–10 the drier it is and so higher values indicate increased drought risk. Here the CDI JV was calculated using precipitation data (SPI) from APHRODITE, FAPAR from MODIS, and soil moisture from ESACCI.
CDI JV is available from February 2000 to December 2015.
Jager, A D, & Vogt, J V. 2015. Analyzing the Combined Drought Indicator (CDI): Demonstration and Analysis of its Evolution during Spring and Summer 2013–2014. Agriculture and Agricultural Science Procedia, 4, 222–231.
CDI JD
The Combined Drought Indicator (CDI) makes use of a combination of common indicators to identify areas that either are affected by or have the potential to be affected by agricultural drought. The method proposed by Jimenez-Donaire et al. (2020; CDI JD) has 4 levels that are determined by combinations of Standardized Precipitation Index (SPI), soil moisture anomaly and Normalised Difference Vegetation Index (NDVI) anomaly. As the level increases from 1-4 the drier it is and so higher values indicate increased drought risk. Here the CDI JD was calculated using precipitation data (SPI) from APHRODITE, NDVI from MODIS, and soil moisture from ESACCI.
CDI JD is available from February 2000 to December 2015.
Jimenez- Donaire, M et al. 2020. Evaluation of a combined drought indicator and its predictive potential for agricultural droughts in Southern Spain. Natural Hazards and Earth System Sciences, 20(1), 21–33.
NDVI
Normalised Difference Vegetation Index (NDVI) compares the amount of infra-red light, which is reflected by healthy plants, to the amount of red light, which is absorbed by healthy plants. NDVI is always between -1 and +1 with -1 to 0 indicating inorganic land cover and 0 to 1 indicating live plants with 0 being the least healthy plants. NDVI indicates the amount of healthy vegetation covering a specific area.
Here the NDVI data was provided by MODIS and is available from February 2000 to June 2020.
Rouse, J W, Haas, R H, Schell, J A, and Deering, D W. 1974. Monitoring vegetation systems in the Great Plains with ERTS. NASA special publication, 351(1974), 309.
SPI
Standardized Precipitation Index (SPI) measures the precipitation anomalies at a given location. SPI can be calculated for accumulation periods which can show how long precipitation anomalies have lasted. Accumulation periods are given in months; for example, SPI-3 is the SPI for a 3-month accumulation period. A negative SPI indicates lower than average rainfall and so increased drought risk. Large anomalies for short accumulations are likely to impact soil moisture whereas anomalies for long accumulations will have more of an effect on water storage such as reservoirs.
SPI is available for 409 observed rain gauges across Thailand with with each station having a different data record length according to data availability.
McKee, T B, Doesken, N J, and Kleist, J. 1993. The relationship of drought frequency and duration to time scales. In Proceedings of the 8th Conference on Applied Climatology (Vol. 17, No. 22, pp. 179–183).
SSI
Standardized Streamflow Index (SSI) measures the streamflow anomalies at a given location. SSI can be calculated for accumulation periods which can show how long the anomalies have lasted. Accumulation periods are given in months; for example, SSI-3 is the SSI for a 3-month accumulation period. A negative SSI indicates lower than average streamflow, with increasingly negative values indicating more severe drought.
SSI is available for 134 gauging stations across Thailand with each station having a different data record length according to data availability.
Vicente-Serrano, S M, López-Moreno, J I, Beguería, S, Lorenzo-Lacruz, J, Azorin-Molina, C, and Morán-Tejeda, E. 2012. Accurate computation of a streamflow drought index. Journal of Hydrologic Engineering, 17(2), 318–332.