Satellite detected water extents between 31 August and 04 September 2024 over Chad

Name: Satellite detected water extents between 31 August and 04 September 2024 over Chad
Creator: United Nations Satellite Centre (UNOSAT)
License: http://www.opendefinition.org/licenses/cc-by-sa

✦ DISCOVERED BY ORIONAIUnited Nations Satellite Centre (UNOSAT)WaterChad

Chad

About this dataset

**UNOSAT code: FL20240820TCD** This map illustrates cumulative satellite-detected water using VIIRS in Chad between 31 August to 04 September 2024. Within the cloud free analysed areas of about 900,000 km², a total of about 22,800 km² of lands appear to be affected with flood waters. Maximum flood water extent appears to have increased of about 3,900 km² since the period between 20 to 24 August 2024. Based on Worldpop population data and the maximum flood water extent, about 820,000 people are potentially exposed or living close to flooded areas. Amongst which ~145,000 people in Logone Oriental Region and ~90,000 people in Mayo-Kebbi Est Region. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT).

Documentation

UNOSAT datasets and maps are produced using a variety of methods. In general, analysts closely review satellite imagery, often comparing two or more images together, and determine notable changes between the images. For damage assessments, refugee or IDP assessments, and similar analyses, these changes are then manually documented in the vector data by the analyst. For flood extractions, landcover mapping and similar analyses, a variety of automated remote sensing techniques are used to extract the relevant information which is then reviewed and revised as necessary by the analyst. In all cases, resulting data is then loaded into a standardized UNOSAT geodatabase and exported asshapefiles for dissemination. This is a preliminary assessment and has not yet been validated in the field. It is important to consider the characteristics of the source imagery used in the analyses when interpreting results. For damage assessments it should be noted that only significant damage to the structural integrity of the buildings analyzed can be seen in imagery, while minor damage such as cracks or holes may not be visible at all. For flood extractions using radar data it is important to note that urban areas and highly vegetated areas may mask the flood signature and result in underestimation of flood waters. Users with specific questions or concerns should contact unosat@unitar.org to seek clarification.

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Satellite detected water extents between 02 and 06 October 2024 over Chad

**UNOSAT code: FL20240820TCD** This map illustrates cumulative satellite-detected water using VIIRS in Chad between 02 to 06 October 2024. Within the cloud free analysed areas of about 1,240,000 km², a total of about 32,000 km² of lands appear to be affected with flood waters. Maximum flood water extent appears to have increased of about 9,000 km² since the period between 31 August to 04 September 2024. Based on Worldpop population data and the maximum flood water extent, about 1,370,000 people are potentially exposed or living close to flooded areas. Amongst which ~320,000 people in Mayo-Kebbi Est Region and ~180,000 people in Logone Oriental Region. This is a preliminary analysis and has not yet been validated in the field. Please send ground feedback to the United Nations Satellite Centre (UNOSAT).