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Estimating wetland methane emissions from the northern high latitudes from 1990 to 2009 using artificial neural networks
Author(s) -
Zhu Xudong,
Zhuang Qianlai,
Qin Zhangcai,
Glagolev Mikhail,
Song Lulu
Publication year - 2013
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/gbc.20052
Subject(s) - wetland , environmental science , latitude , water table , hydrology (agriculture) , greenhouse gas , methane , precipitation , ecosystem , atmospheric sciences , climate change , climatology , groundwater , meteorology , ecology , geology , geography , oceanography , geotechnical engineering , geodesy , biology
Methane (CH 4 ) emissions from wetland ecosystems in nothern high latitudes provide a potentially positive feedback to global climate warming. Large uncertainties still remain in estimating wetland CH 4 emisions at regional scales. Here we develop a statistical model of CH 4 emissions using an artificial neural network (ANN) approach and field observations of CH 4 fluxes. Six explanatory variables (air temperature, precipitation, water table depth, soil organic carbon, soil total porosity, and soil pH) are included in the development of ANN models, which are then extrapolated to the northern high latitudes to estimate monthly CH 4 emissions from 1990 to 2009. We estimate that the annual wetland CH 4 source from the northern high latitudes (north of 45°N) is 48.7 Tg CH 4 yr −1 (1 Tg = 10 12 g) with an uncertainty range of 44.0~53.7 Tg CH 4 yr −1 . The estimated wetland CH 4 emissions show a large spatial variability over the northern high latitudes, due to variations in hydrology, climate, and soil conditions. Significant interannual and seasonal variations of wetland CH 4 emissions exist in the past 2 decades, and the emissions in this period are most sensitive to variations in water table position. To improve future assessment of wetland CH 4 dynamics in this region, research priorities should be directed to better characterizing hydrological processes of wetlands, including temporal dynamics of water table position and spatial dynamics of wetland areas.