title: Multi-scale geospatial agroecosystem modeling: a case study on the influence of soil data resolution on carbon budget estimates.
abstract: The development of effective measures to stabilize atmospheric CO2 concentration and mitigate negative impacts of climate change requires accurate quantification of the spatial variation and magnitude of the terrestrial carbon (C) flux. However, the spatial pattern and strength of terrestrial C sinks and sources remain uncertain. In this study, we designed a spatially-explicit agroecosystem modeling system by integrating the Environmental Policy Integrated Climate (EPIC) model with multiple sources of geospatial and surveyed datasets (including crop type map, elevation, climate forcing, fertilizer application, tillage type and distribution, and crop planting and harvesting date), and applied it to examine the sensitivity of cropland C flux simulations to two widely used soil databases (i.e. State Soil Geographic-STATSGO of a scale of 1:250,000 and Soil Survey Geographic-SSURGO of a scale of 1:24,000) in Iowa, USA. To efficiently execute numerous EPIC runs resulting from the use of high resolution spatial data (56m), we developed a parallelized version of EPIC. Both STATSGO and SSURGO led to similar simulations of crop yields and Net Ecosystem Production (NEP) estimates at the State level. However, substantial differences were observed at the county and sub-county (grid) levels. In general, the fine resolution SSURGO data outperformed the coarse resolution STATSGO data for county-scale crop-yield simulation, and within STATSGO, the area-weighted approach provided more accurate results. Further analysis showed that spatial distribution and magnitude of simulated NEP were more sensitive to the resolution difference between SSURGO and STATSGO at the county or grid scale. For over 60% of the cropland areas in Iowa, the deviations between STATSGO- and SSURGO-derived NEP were larger than 1MgCha(-1)yr(-1), or about half of the average cropland NEP, highlighting the significant uncertainty in spatial distribution and magnitude of simulated C fluxes resulting from differences in soil data resolution.
authors.affiliation: Joint Global Change Research Institute, Pacific Northwest National Laboratory and University of Maryland, College Park, MD 20740, USA. Electronic address: xuesong.zhang@pnnl.gov.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Geographical Sciences, University of Maryland, College Park, MD 20740, USA.
authors.forename: Ritvik
authors.initials: R
authors.lastname: Sahajpal
authors.affiliation: Joint Global Change Research Institute, Pacific Northwest National Laboratory and University of Maryland, College Park, MD 20740, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Manowitz
authors.affiliation: School of Environment and Natural Resources, The Ohio Agricultural Research and Development Center, Ohio State University, Wooster, OH 44691, USA.
authors.forename: Kaiguang
authors.initials: K
authors.lastname: Zhao
authors.affiliation: U.S. Environmental Protection Agency, National Center for Environmental Assessment, Arlington, VA 22202, USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Leduc
authors.affiliation: Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD 20740, USA.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiong
authors.affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Aiping
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Joint Global Change Research Institute, Pacific Northwest National Laboratory and University of Maryland, College Park, MD 20740, USA; Department of Geographical Sciences, University of Maryland, College Park, MD 20740, USA.
authors.forename: Roberto C
authors.initials: RC
authors.lastname: Izaurralde
authors.affiliation: Joint Global Change Research Institute, Pacific Northwest National Laboratory and University of Maryland, College Park, MD 20740, USA.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Thomson
authors.affiliation: Joint Global Change Research Institute, Pacific Northwest National Laboratory and University of Maryland, College Park, MD 20740, USA.
authors.forename: Tristram O
authors.initials: TO
authors.lastname: West
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Wilfred M
authors.initials: WM
authors.lastname: Post
mesh_terms: D002244:Carbon; D057486:Carbon Cycle; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D005843:Geography; D008962:Models, Theoretical; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D002244:Carbon
keywords: Climate change; EPIC; Net Ecosystem Production; Parallel computing; SSURGO; STATSGO; Spatial resolution