Satellite detected water extents in upper central region, Thailand as of 2 October 2021

**UNOSAT code: FL20210928THA** This map illustrates satellite-detected surface waters in Central and Western parts of Thailand as observed from a Sentinel-1 image acquired on 21 October 2021 at 06:09 local time. Within the analyzed area of about 90,000 km2 , about 3,200 km2 of lands appear to be flooded. The water extent appears to have receded of about 70 km2 since 10 October 202. Based on Worldpop population data and the detected surface waters in the analyzed area, the potentially exposed population is 370,000 people mainly located in province of Phra Nakhon Si Ayutthaya with ~ 99,000 people, Suphan Buri with ~ 88,000 people, and Nakhon Sawan with ~ 47,000 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.

**UNOSAT code: FL20210928THA** This map illustrates satellite-detected surface waters in Central part of Thailand as observed from a Sentinel-1 image acquired on 3 October 2021 at 06:08 local time. Within the analyzed area of about 91,000 km2 , about 3,300 km2 of lands appear to be flooded. The water extent appears to have decreased of about 180 km2 since 27 September 2021. Based on Worldpop population data and the detected surface waters in the analyzed area, the potentially exposed population is 350,000 people mainly located in the Ayutthaya Province with ~ 76,000 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.

**UNOSAT code: FL20210928THA** 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 5 Oct 2021 at 18:20 local time and using an automated analysis with Machine learning method. Within the analyzed area of about 40,500 km2 , about 770 km2 of lands appear to be flooded. The water extent appears to have decreased of about 70 km2 since 29 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 Phimai with ~ 10,400 people, Non Sung with ~ 9,000 people, Mueang Chaiyaphum with ~ 6,700 people, Mueang Khon Kaen with ~ 4,500 people, and Chonnabot Thai with ~ 4,300 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.

**UNOSAT code: FL20210928THA** This map illustrates satellite-detected surface waters in Northeastern part of Thailand as observed from a Sentinel-1 image acquired on 10 Oct 2021 at 06:00 local time and using an automated analysis with Machine learning method. Within the analyzed area of about 60,000 km2 , about 660 km2 of lands appear to be flooded. The water extent appears to have decreased of about 100 km2 since 5 October 2021 and moved toward east part. 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 Mueang Khon Kaen with ~ 6,300, Kosum Phisai with ~ 6,000 people, and Phimai with ~ 5,300 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.

**UNOSAT code: FL20210928THA** Summary Of Findings; Floodwaters observed in 17 provinces as of 2 November 2021; Receding flood waters observed in Central Region as of 2 November 2021; Standing flood waters observed in Sukhothai, Phitsanulok, Kamphaeng Phet, Phichit, Phetchabun, Nakhon Sawan, Uthai Thani, and Kanchanaburi provinces as of 2 November 2021;  Increased standing flood waters observed in Chai Nat, Suphan Buri, Sing Buri, Ang Thong, Saraburi, Lop Buri, Ayutthaya, Nakhon Pathom and Pathum Thani provinces as of 2 November 2021.

**UNOSAT code: FL20210928THA** This map illustrates satellite-detected surface waters in Northeastern part of Thailand as observed from a Sentinel-1 image acquired on 17 Oct 2021 at 18:20 local time and using an automated analysis with Machine learning method. Within the analyzed area of about 60,000 km2 , about 810 km2 of lands appear to be flooded. The water extent appears to have increased of about 220 km2 since 16 October 2021. Based on Worldpop population data and the detected surface waters in the analyzed area, the potentially exposed population is 80,000 people mainly located in province of Khon Kaen Province with ~ 24,000 and Nakhon Ratchasima with ~ 22,000 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.