Contribution of Environmental Forcings to US Runoff Changes for the Period 1950–2010

TitleContribution of Environmental Forcings to US Runoff Changes for the Period 1950–2010
Publication TypeJournal Article
Year of Publication2018
AuthorsForbes, Whitney L., Mao Jiafu, Jin Mingzhou, Kao Shih-Chieh, Fu Wenting, Shi Xiaoying, Riccuito Daniel M., Thornton Peter E., Ribes Aurelien, Wang Yutao, Piao Shilong, Zhao Tianbao, Schwalm Christopher R., Hoffman Forrest M., Fisher Joshua B., Ito Akihiko, Poulter Ben, Fang Yuanyuan, Tian Hanqin, Jain Atul K., and Hayes Daniel J.
JournalEnvironmental Research Letters
Volume13
Number5
Pages054023
Date Published05/2018
Abstract

Runoff in the United States is changing, and this study finds that the measured change is dependent on the geographic region and varies seasonally. Specifically, observed annual total runoff had an insignificant increasing trend in the US between 1950 and 2010, but this insignificance was due to regional heterogeneity with both significant and insignificant increases in the eastern, northern, and southern US, and a greater significant decrease in the western US. Trends for seasonal mean runoff also differed across regions. By region, the season with the largest observed trend was autumn for the east (positive), spring for the north (positive), winter for the south (positive), winter for the west (negative), and autumn for the US as a whole (positive). Based on the detection and attribution analysis using gridded WaterWatch runoff observations along with semi-factorial land surface model simulations from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we found that while the roles of CO2 concentration, nitrogen deposition, and land use and land cover were inconsistent regionally and seasonally, the effect of climatic variations was detected for all regions and seasons, and the change in runoff could be attributed to climate change in summer and autumn in the south and in autumn in the west. We also found that the climate-only and historical transient simulations consistently underestimated the runoff trends, possibly due to precipitation bias in the MsTMIP driver or within the models themselves.

URLhttp://dx.doi.org/10.1088/1748-9326/aabb41
DOI10.1088/1748-9326/aabb41
Journal: Environmental Research Letters
Number: 5
Volume: 13

Runoff in the United States is changing, and this study finds that the measured change is dependent on the geographic region and varies seasonally. Specifically, observed annual total runoff had an insignificant increasing trend in the US between 1950 and 2010, but this insignificance was due to regional heterogeneity with both significant and insignificant increases in the eastern, northern, and southern US, and a greater significant decrease in the western US. Trends for seasonal mean runoff also differed across regions. By region, the season with the largest observed trend was autumn for the east (positive), spring for the north (positive), winter for the south (positive), winter for the west (negative), and autumn for the US as a whole (positive). Based on the detection and attribution analysis using gridded WaterWatch runoff observations along with semi-factorial land surface model simulations from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we found that while the roles of CO2 concentration, nitrogen deposition, and land use and land cover were inconsistent regionally and seasonally, the effect of climatic variations was detected for all regions and seasons, and the change in runoff could be attributed to climate change in summer and autumn in the south and in autumn in the west. We also found that the climate-only and historical transient simulations consistently underestimated the runoff trends, possibly due to precipitation bias in the MsTMIP driver or within the models themselves.

DOI: 10.1088/1748-9326/aabb41
Year of Publication: 2018
Citation:
Forbes, W, J Mao, M Jin, S Kao, W Fu, X Shi, D Riccuito, P Thornton, A Ribes, Y Wang, S Piao, T Zhao, C Schwalm, F Hoffman, J Fisher, A Ito, B Poulter, Y Fang, H Tian, A Jain, and D Hayes.  2018.  "Contribution of Environmental Forcings to US Runoff Changes for the Period 1950–2010."  Environmental Research Letters 13(5): 054023, doi:10.1088/1748-9326/aabb41.