Monitoring Water Use Efficiency Changes in the Changbai Mountains, China Using MODIS Images

Water use efficiency (WUE) quantifies the trade-off between ecosystem productivity and water loss. Monitoring the spatio-temporal changes of WUE and relationships with climate in different regions is of great significance for deeply understanding the response of ecosystem functions to climate change. Based on MODIS images and meteorological data, WUE and its response to climate change were investigated using the trend analysis, sensitivity analysis and correlation analysis methods in the Changbai Mountains, China during 2000–2014. We found that vegetation WUE showed obvious spatial differentiation and increased with fluctuations. The descending order of WUE was mixed forest > coniferous forest > broadleaved forest > grassland > cultivated land > wetland. WUE was positively correlated with relative humidity, while showed negative relation with sunshine duration and temperature. The response of WUE variations to precipitation change was more complicated. The sensitivity of WUE to four climate factors presented different threshold effects.