Title Of The Magazine |
GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS |
Year Information |
2023 |
KeyWord |
Irrigation mapping, Irrigation performance, GMIE, Google Earth Engine |
Authors |
Bingfang Wu, Fuyou Tian, Mohsen Nabil, Jos´e Bofana, Yuming Lu, Abdelrazek Elnashar, Awetahegn Niguse Beyene, Miao Zhang, Hongwei Zeng, Weiwei Zhu |
Intro |
Accurate global irrigation information is essential for managing water scarcity and improving food security.
However, the mapping of high-resolution irrigation at the global scale is challenging due to the wide range of
climate conditions, crop types and phenology, ambiguous and heterogeneous spectral features, and farming
practices. Here, a robust method is proposed using irrigation performance under drought stress as a proxy for
crop productivity stabilization and crop water consumption. For each irrigation mapping zone (IMZ), dry months
in the 2017–2019 period and the driest months in the 2010–2019 period were identified over the growing
season. The thresholds of the normalized difference vegetation index (NDVI) in the dry months from 2017 to
2019 and the NDVI deviation (NDVIdev) in the driest month were identified to separate irrigated and rainfed
cropland with samples. The final threshold from either the NDVI or the NDVIdev of the IMZ was determined with
a higher overall accuracy in separating irrigated and non-irrigated areas. The results show that the global
maximum irrigation extent (GMIE) at a 30-m resolution was 23.38% of global cropland in 2010–2019, with an
overall accuracy of 83.6% globally and significant regional differences in irrigation proportions ranging from
1.1% in western Africa to 100% in Old World deserts among the 110 IMZs and from 0.4% in Belarus to 80.2% in
Pakistan and 100% in Egypt among 45 countries. The study quantitatively distinguished annually and intermittently
irrigated regions, which had values of 42% and 58% of global cropland, respectively, by applying
indicators. This method, using the NDVI and NDVIdev thresholds, is simple, concrete and reproducible and better
for zones with homogeneous weather conditions. The study offers independent, consistent and comparable information
for defining the baseline, tracking changes in irrigation infrastructure, and leading future changes in
how stakeholders plan and design irrigation systems. |
Links To Magazines |
https://doi.org/10.1016/j.gloenvcha.2023.102652 |