Carbon flux prediction in farmland ecosystem based on hydrometeorological factors
Using the carbon and water fluxes and hydrometeorological data observed by the flux tower of Yucheng Station of China Flux Observation Network(ChinaFLUX)in the lower reaches of the Yellow River Basin,the main controlling environmental factors af-fecting the CO2 exchange capacity of the farmland ecosystem were determined based on the feature importance method.A machine learning model for carbon flux prediction was constructed based on all environmental factors and master environmental factors,and the mean square error(MSE),mean absolute error(MAE)and coefficient of determination(R2)were used to evaluate the model predic-tion performance of the test set.The results showed that,the main environmental driving factors affecting carbon flux in Yucheng agro-ecosystems were net radiation,soil temperature,vapor pressure deficit and soil water content.Compared with single models,the en-semble models had better learning and prediction performances in the testing set.Among the single models,MLPRegressor model could better predict NEE with R2 of 0.830,MSE of 3.113 and MAE of 1.283.Among the ensemble models,XGBRegressor model had better prediction performance with R2 of 0.845,MSE of 2.838 and MAE of 1.149.The machine learning models using the main four en-vironmental driving factors had the same prediction performances as the models using all environmental factors.