Paddy rice methane emissions across Monsoon Asia

• DOI: 10.1016/j.rse.2022.113335
• Publication Date: 2022-11-14T05:56:48Z
• Authors: Zutao Ouyang; Robert B. Jackson; Gavin McNicol; Etienne Fluet-Cho...; Benjamin R.K. Runkle; Dario Papale; Sara H. Knox; Sarah Cooley; Kyle B. Delwiche; Sarah Feron; Jeremy Andrew Irvin; Avni Malhotra; Muhammad Muddasir; Simone Sabbatini; Ma. Carmelita R. ...; Alessandro Cescatti; Chi-Ling Chen; Jinwei Dong; Bryant N. Fong; Haiqiang Guo; Lu Hao; Hiroki Iwata; Qingyu Jia; Weimin Ju; Minseok Kang; Hong Li; Joon Kim; Michele L. Reba; Amaresh Kumar Nayak; Debora Regina Rob...; Youngryel Ryu; Chinmaya Kumar Swain; Benjei Tsuang; Xiangming Xiao; Wenping Yuan; Geli Zhang; Yongguang Zhang
• Keywords: Paddy field

Although rice cultivation is one of the most important agricultural sources methane (CH4) and contributes ∼8% total global anthropogenic emissions, large discrepancies remain among estimates CH4 emissions from (ranging 18 to 115 Tg yr−1) due a lack observational constraints. The spatial distribution paddy-rice has been assessed at regional-to-global scales by bottom-up inventories land surface models over coarse resolution (e.g., > 0.5°) or units agro-ecological zones). However, high-resolution flux capable capturing effects local climate management practices on as well replicating in situ data, challenging produce because scarcity maps insufficient understanding predictors. Here, we combine methane-flux data 23 eddy covariance sites MODIS remote sensing with machine learning 1) evaluate data-driven model performance variable importance for predicting fluxes; 2) gridded up-scaling 5000-m across Monsoon Asia, where ∼87% area cultivated ∼ 90% production occurs. Our random-forest achieved Nash-Sutcliffe Efficiency values 0.59 0.69 8-day fluxes site mean respectively, temperature, biomass water-availability-related indices We estimate average annual (winter fallow season excluded) paddy throughout Asia be 20.6 ± 1.1 yr−1 2001–2015, which lower range previous inventory-based (20–32 yr−1). also suggest that this region have declining 2007 through 2015 following declines both growing emission rates per unit area, suggesting likely not contributed renewed growth atmospheric recent years.