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How does GISTDA use satellite data to monitor flooding in Thailand?
Flooding is one of the natural disasters that could cause damage to housing and infrastructure, disrupt people’s daily lives, and affect the economy both directly and indirectly.
GISTDA or the Geo-Informatics and Space Technology Development Agency, has been utilizing geo-informatics and satellite data to monitor and respond to flooding, to ensure the minimum damage caused by this natural disaster.
One of the primary sources for monitoring Thailand’s flooding is satellite data, from GISTDA’s Thaichote and THEOS-2 satellites, along with GISTDA’s partner satellites like the Sentinel-1A and Radarsat-2. Information acquired from these satellites is then provided for essential key workers and organizations involved in planning and responding to natural disasters.
But one of the questions remains, how can a satellite that orbits at an altitude of more than 500 kilometers detect flooding on the Earth's surface?
Let’s begin with THEOS-2, Thailand’s second Earth observation satellite, equipped with a Panchromatic camera at a resolution of 50 centimeters, and a Multispectral camera capable of resolving objects larger than 2 meters. THEOS-2 was launched into a 621-kilometer Sun-synchronous orbit on October 9, 2023, and began providing high-resolution imagery in May 2024.
GISTDA's THEOS-2 satellite helped capture high-resolution while it orbited over Thailand on August 26, showing the area affected by flooding, along with changes in the color of the Yom River from sediment flowing downstream.
The ESA's Sentinel-1A and CSA's Radarsat-2 satellites are equipped with C-band Synthetic Aperture Radar, which emits radar pulses and measures the backscattered signals from the Earth's surface. This technique helps both satellites to make continuous observations during daytime and nighttime, under all weather conditions.
By measuring the strength and polarization of the backscattered signals, the C-band Synthetic Aperture Radar can detect the physical properties of the surface, allowing scientists to distinguish land areas from flooded regions. They can also compare the latest data with the previous flyover, which could differentiate the affected area from natural water sources.
However, satellite data still has limitations on its flyover period, making it difficult to acquire the latest data necessary for real-time planning and response. This is why GISTDA decided to deploy its UAVs (Unmanned Aerial Vehicles) for real-time, localized monitoring of flooding in Thailand; all the data acquired from satellites and UAVs will be provided to the necessary organization to help with planning and responding efficiently.
You can access the latest updates and information regarding the 2024 flooding in Thailand via the GISTDA Facebook page and disaster.gistda.or.th
Reference :
https://www.earthdata.nasa.gov/learn/backgrounders/what-is-sar
https://esamultimedia.esa.int/docs/S1-Data_Sheet.pdf
https://www.asc-csa.gc.ca/eng/satellites/radarsat2/
https://disaster.gistda.or.th/
Flooding is one of the natural disasters that could cause damage to housing and infrastructure, disrupt people’s daily lives, and affect the economy both directly and indirectly.
GISTDA or the Geo-Informatics and Space Technology Development Agency, has been utilizing geo-informatics and satellite data to monitor and respond to flooding, to ensure the minimum damage caused by this natural disaster.
One of the primary sources for monitoring Thailand’s flooding is satellite data, from GISTDA’s Thaichote and THEOS-2 satellites, along with GISTDA’s partner satellites like the Sentinel-1A and Radarsat-2. Information acquired from these satellites is then provided for essential key workers and organizations involved in planning and responding to natural disasters.
But one of the questions remains, how can a satellite that orbits at an altitude of more than 500 kilometers detect flooding on the Earth's surface?
Let’s begin with THEOS-2, Thailand’s second Earth observation satellite, equipped with a Panchromatic camera at a resolution of 50 centimeters, and a Multispectral camera capable of resolving objects larger than 2 meters. THEOS-2 was launched into a 621-kilometer Sun-synchronous orbit on October 9, 2023, and began providing high-resolution imagery in May 2024.
GISTDA's THEOS-2 satellite helped capture high-resolution while it orbited over Thailand on August 26, showing the area affected by flooding, along with changes in the color of the Yom River from sediment flowing downstream.
The ESA's Sentinel-1A and CSA's Radarsat-2 satellites are equipped with C-band Synthetic Aperture Radar, which emits radar pulses and measures the backscattered signals from the Earth's surface. This technique helps both satellites to make continuous observations during daytime and nighttime, under all weather conditions.
By measuring the strength and polarization of the backscattered signals, the C-band Synthetic Aperture Radar can detect the physical properties of the surface, allowing scientists to distinguish land areas from flooded regions. They can also compare the latest data with the previous flyover, which could differentiate the affected area from natural water sources.
However, satellite data still has limitations on its flyover period, making it difficult to acquire the latest data necessary for real-time planning and response. This is why GISTDA decided to deploy its UAVs (Unmanned Aerial Vehicles) for real-time, localized monitoring of flooding in Thailand; all the data acquired from satellites and UAVs will be provided to the necessary organization to help with planning and responding efficiently.
You can access the latest updates and information regarding the 2024 flooding in Thailand via the GISTDA Facebook page and disaster.gistda.or.th
Reference :
https://www.earthdata.nasa.gov/learn/backgrounders/what-is-sar
https://esamultimedia.esa.int/docs/S1-Data_Sheet.pdf
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