Fitri Lake Water Extent

ExtractEO, an automatic water detection workflow developped by ICube-SERTIT, was applied to the Sentinel-2 time series covering Fitri Lake from January 2017 to February 2021, deriving a lake mask for each Sentinel-2 acquisition date.

The ExtractEO pipeline downloaded 246 Sentinel-2 images from the CREODIAS platform and detected water extents based on a multilayer perceptron (MLP) algorithm combined with the use of the Global Surwace Water dataset for sampling.

The lake surface is calculated on each exploitable date (i.e. no clouds over the lake) from all lake masks. Then the results feed the Lake Water Extent (LWE) curve.

Occurence products are also derived from lake water masks: annual occurence and global occurence over the 4-year observation period.

• 246 Sentinel-2 images processed
• 153 lake masks produced from exploitable data (no clouds over the lake)
• Lake surface areas calculated within the AOI
• Similar water surface dynamics in 2017, 2018, 2019
• Significant flood event in 2020 (max water extent 2020 = 2x max water extent [2017-2019])
• Maximum lake area (22.09.2020): 1249 km²
• Minimum lake area (16.05.2017): 194 km²

Water occurence layers are generated from the 153 lake masks exploitable:

• Annual occurence (2017/2018/2018/2020) expressed as a percentage of total annual observations [0;100]
• Annual occurence (2017/2018/2018/2020) expressed as the number of months in which water is present [0:12]
• Occurence of the full period (January 2017 - February 2021) expressed as a percentage of total observations [0;100]

 ICube-SERTIT  helps space serve the Earth producing geo-information from space imagery As a regional, national and European operator, it responds to society’s needs offering solutions in risk management, land planning, natural resource management, the environment and sustainable development.

• Hervé Yésou
• Jérôme Maxant
• Thomas Ledauphin