16 MAY 2025 (FRI) 15:00-15:15

HKU GEOGRAPHY: Monthly Research Talks

The first universal algorithm for mapping cropland inundation status throughout the growing season

Date: 16 MAY 2025 (Friday)

Time: 15:00-15:15 (HKT)

Via Zoom: https://hku.zoom.us/j/98300713382?pwd=dGdqelhpWUwyOENmTUJyalVKemtHQT09

(No registration required)

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Abstract:

Spatiotemporal variation of croplands' inundation status significantly affects irrigation water consumption, methane emission and crop yield. However, spatially-explicit information on croplands' inundation regime has not been able to retrieve from publicly-available satellite data. The main challenges include the inability of optical sensors to observe the inundation status beneath dense canopy and the strong variability of SAR backscatters over inundated croplands. Here, we propose a novel algorithm using SWOT KaRIn's coherent power to differentiate between non-inundated, partially-inundated, and fully-inundated fields throughout the growing season. This approach mitigates disturbances from factors including radar incidence angle, vegetation water content, wind speed, and random noises. Applied in Sanjiang Plain, central and southern Jiangsu province, northeastern Thailand, and Arkansas, USA, our spatiotemporal cropland inundation status mapping aligns well with field investigations, PhenoCam photos, and published literature.

Dr. Yongzhe CHEN

Post-doctoral Research Fellow, Department of Geography, HKU

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