Projected changes of regional lake hydrologic characteristics in response to 21st century climate change

Inland lakes are socially and ecologically important components of many regional landscapes. Exploring lake responses to plausible future climate scenarios can provide important information needed to inform stakeholders of likely effects of hydrologic changes on these waterbodies in coming decades. To assess potential climate effects on lake hydrology, we combined a previously published spatially explicit, processed-based hydrologic modeling framework implemented over the lake-rich landscape of the Northern Highlands Lake District within the United States with an ensemble of climate change scenarios for the 2050s (2041–2070) and 2080s (2071–2100). Model results quantify the effects of climate change on water budgets and lake stage elevations for 3692 lakes and highlight the importance of landscape and hydrologic setting for the response of specific lake types to climate change. All future climate projections resulted in loss of ice cover and snowpack as well as increased evaporation, but variability in climate projections (warmer conditions, wet winters combined with wet or dry summers) interacted with lake characteristics and landscape position to produce variable lake hydrologic changes. Water levels for drainage lakes (lakes with substantial surface water inflows and outflows) showed nearly no change, whereas minimum water levels for seepage lakes (minimal surface water fluxes) decreased by an average of up to 2.64 m by the end of the 21st century. Our physically based modeling approach is parsimonious and computationally efficient and can be applied to other lake-rich regions to investigate interregional variability in lake hydrologic response to future climate scenarios.内陆湖泊是诸多区域景观中兼具社会与生态重要性的组成要素。探究湖泊对合理未来气候情景的响应，可为利益相关方了解未来数十年水文变化对这类水体的潜在影响提供关键参考信息。为评估气候变化对湖泊水文的潜在影响，我们将此前已发表的、应用于美国北部高地湖区（Northern Highlands Lake District）这一湖泊密布区域的空间显式（spatially explicit）、基于过程的水文建模（process-based hydrologic modeling）框架，与2050年代（2041–2070年）及2080年代（2071–2100年）的气候变化情景集合（ensemble of climate change scenarios）相结合。模型结果量化了3692个湖泊的气候变化对水量平衡（water budgets）与湖泊水位高程（lake stage elevations）的影响，并凸显了景观与水文背景对特定湖泊类型响应气候变化的关键作用。所有未来气候预估均显示冰盖与积雪将消失，蒸发量亦会上升；但气候预估的变异性（暖化情境、湿润冬季搭配湿润或干燥夏季）与湖泊特征及景观位置相互作用，使得不同湖泊的水文变化呈现出多样性。排水型湖泊（drainage lakes，即具备显著地表水体流入与流出的湖泊）的水位几乎无变化，而渗漏型湖泊（seepage lakes，即地表水体通量极小的湖泊）的最低水位在21世纪末平均下降最高可达2.64米。本研究采用的基于物理过程的建模方法简约（parsimonious）且计算效率高，可推广应用至其他湖泊密布的区域，以探究不同区域湖泊水文对未来气候情景响应的差异性。