Akbariyeh Simin, Pena Cesar Augusto Gomez, Wang Tiejun, Mohebbi Amin, Bartelt-Hunt Shannon, Zhang Jianmin, Li Yusong
Department of Civil and Environmental Engineering, California Polytechnic State University, N Perimeter Rd., San Luis Obispo, CA 93405, USA.
Department of Civil Engineering, Technological University of Panama - Regional Center of Chiriqui, Sixth West Avenue, David District, Chiriqui County, 0401, Panama.
Sci Total Environ. 2019 Oct 1;685:514-526. doi: 10.1016/j.scitotenv.2019.05.417. Epub 2019 Jun 1.
Understanding the impacts of future climate change on soil hydrological processes and solute transport is crucial to develop appropriate strategies to minimize the adverse impacts of agricultural activities on groundwater quality. To evaluate the direct effects of climate change on the transport and accumulation of nitrate-N, we developed an integrated modeling framework combining climatic change, nitrate-N infiltration in the unsaturated zone, and groundwater level fluctuations. The study was based on a center-pivot irrigated corn field at the Nebraska Management Systems Evaluation Area (MSEA) site. Future groundwater recharge (GR) and actual evapotranspiration (ET) rates were predicted via an inverse vadose zone modeling approach by using climatic data generated by the Weather Research and Forecasting (WRF) climate model under the RCP 8.5 scenario, which was downscaled from the global CCSM4 model to a resolution of 24 km by 24 km. A groundwater flow model was first calibrated on the basis of historical groundwater table measurements and then applied to predict the future groundwater table in 2057-2060. Finally, the predicted future GR rate, ET rate, and groundwater level, together with future precipitation data from the WRF climate model, were used in a three-dimensional (3D) model to predict nitrate-N concentrations in the subsurface (saturated and unsaturated parts) from 2057 to 2060. The future GR was predicted to decrease in the study area, as compared with the average GR data from the literature. Correspondingly, the groundwater level was predicted to decrease (30 to 60 cm) over the 5 years of simulation in the future. The nitrate-N mass in the simulation domain was predicted to increase but at a slower rate than in the past. Sensitivity analysis indicated that the accumulation of nitrate-N is sensitive to groundwater table elevation changes and irrigation rates.
了解未来气候变化对土壤水文过程和溶质运移的影响，对于制定适当策略以尽量减少农业活动对地下水质量的不利影响至关重要。为了评估气候变化对硝态氮运移和积累的直接影响，我们开发了一个综合建模框架，该框架结合了气候变化、非饱和带硝态氮入渗以及地下水位波动。该研究基于内布拉斯加州管理系统评估区（MSEA）站点的中心支轴灌溉玉米田。通过反演渗流带建模方法，利用天气研究与预报（WRF）气候模型在RCP 8.5情景下生成的气候数据预测未来的地下水补给（GR）和实际蒸散（ET）速率，该数据是从全球CCSM4模型降尺度到24 km×24 km分辨率的。首先根据历史地下水位测量数据对地下水流模型进行校准，然后应用该模型预测2057 - 2060年的未来地下水位。最后，将预测的未来GR速率、ET速率和地下水位，以及WRF气候模型的未来降水数据，用于三维（3D）模型，以预测2057年至2060年地下（饱和和非饱和部分）硝态氮浓度。与文献中的平均GR数据相比，研究区域未来的GR预计会下降。相应地，在未来5年的模拟中，地下水位预计将下降（30至60厘米）。模拟域中的硝态氮质量预计会增加，但增速比过去慢。敏感性分析表明，硝态氮的积累对地下水位高程变化和灌溉速率敏感。
