Climate-driven variability in lake and wetland distribution across the Prairie Pothole Region: From modern observations to long-term reconstructions with space-for-time substitution

摘要

This study was designed (1) to explore the links between climate variability and the population dynamics of closed-basin surface water bodies of the Prairie Pothole Region (PPR) in North America, and (2) to test the validity of space-for-time (SFT) substitution approach for the analysis of hydrologic systems. Observational results from 1981 to 2000 show that the climate with respect to annual residual moisture (ε, i.e., precipitation minus potential evaporation or evapotranspiration) of the PPR changed across space (over 0.6 m) and time (over 0.3 m in central North Dakota), causing spatiotemporal variability in water areas and water body numbers. Spatial analysis of a suite of surface water complexes along a spatial e gradient in the Missouri Coteau shows that a four parameter Boltzmann function quantitatively describes how the number of water bodies (TV) varied as a function of 5-year average annual e (R~2 = 0.76). Temporal analysis of monthly TV data (1931-2005) reconstructed by a hydrologic model also demonstrates that values of temporally varying TV were highly correlated with ε and yielded a nearly identical Boltzmann function. This result confirms the validity of SFT substitution and suggests that detailed modern spatial data can be used to interpret hydrologic system behaviors under past or future climate conditions. This study also has important regional-scale implications for water resources management by providing a complete picture of the spatiotemporal water body distribution across the entire PPR and the potential for rapidly converting climate predictions into surface water assessments.