Product ID: 3374 - English
Published: 30 Sep, 2021
GLIDE: FL20210928THA

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This map illustrates satellite-detected surface waters in Khon Kaen, Chaiyaphum, Nakhon Ratchasima, and Nong Bua Lam Phu provinces, Thailand as observed from a Sentinel-1 image acquired on 29 Sep 2021 at 18:22 local time. Within the analyzed area of about 36,350 km2 , about 830 km2 of lands appear to be flooded. The water extent appears to have increased of about 80 km2 since 27 September 2021. Based on Worldpop population data and the detected surface waters in the analyzed area, the potentially exposed population is mainly located in the district of Non Sung with ~ 14,000 people, Mueang Chaiyaphum with ~ 13,400 people, Ban Khwao with ~ 5,900 people, and Non Thai with ~ 5,400 people.

This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to United Nations Satellite Centre (UNOSAT).
Important note: Flood analysis from radar images may underestimate the presence of standing waters in built-up areas and densely vegetated areas due to backscattering properties of the radar signal.
Satellite Data: Sentinel-1
Imagery Dates : 29 Sep 2021 at 11:22 UTC
Resolution: 10 m
Copyright: Contains modified Copernicus Sentinel Data [2021]
Source: ESA
Flood data as of 27 Sep 2021 : GISTDA (
Administrative boundaries: Royal Thai Survey Department
Population data: WorldPop [2020]
Reference Water: JRC
Populated place: OpenStreetMap
Road data: OpenStreetMap
Waterways: OpenStreetMap
Background: ALOS Global DSM
Insets: Sentinel-2/ 28 Sep 2021 at 10:35 local time
Pre image analysis : GISTDA, Thailand
Post image analysis : United Nations Satellite Centre (UNOSAT)
Production: United Nations Satellite Centre (UNOSAT)