Abstract The main purpose of this work is to evaluate diffuse groundwater recharge and its temporal dynamics at sites with different landscapes and soil profiles under observed and projected climate variability. Three typical sites with different landscapes and topsoil profiles were chosen for the field study. Field work consisted of pit development and soil sample collection for laboratory study using the centrifuge method. Soil hydraulic parameters were obtained by the RETC code using the observed values of volumetric water content vs. pressure head. HYDRUS-1D code was used to estimate groundwater recharge based on a 70-year (1945–2015) meteorological dataset with daily resolution (including values of precipitation, air temperature, wind speed, and humidity). This dataset was preprocessed using our SURFBAL code to calculate the surface and topsoil water and energy balance. Retrospective historical simulation results showed that there was a considerable variation in the mean annual groundwater recharge values (49–104 mm/year) for the three studied profiles. The temporal change in groundwater recharge occurred relatively synchronously at all sites and was governed by the change in the current annual aridity index. The results of this historical simulation did not reveal any traces of climate change in the groundwater recharge of the studied region in the last 30–40 years. To predict the recharge variations in the second half of the 21st century, the LARSWG forecast weather generator with the climate projections of the 5th General Circulation Models (GCMs) from the Coupled Model Intercomparison Project 5 (CMIP5) family was used. On average in the case of climate development under the maximum greenhouse gas emissions RCP8.5 scenario, there will be a reduction in groundwater recharge in the studied region in 2060–2080, caused by two factors: change of aridity index, which determines evapotranspiration during a warm season and the accumulation of snow and subsequent meltwater infiltration during the snowmelt periods.

中文翻译：

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观测和预测气候下时空补给的变化：俄罗斯黑土地区特定地点的模拟

摘要 这项工作的主要目的是评估在观测和预测的气候变率下具有不同景观和土壤剖面的地点的扩散地下水补给及其时间动态。选择了三个具有不同景观和表土剖面的典型地点进行实地研究。实地工作包括坑开发和使用离心机方法进行实验室研究的土壤样品收集。土壤水力参数通过 RETC 代码使用体积含水量与压头的观测值获得。HYDRUS-1D 代码用于基于 70 年（1945-2015）具有每日分辨率（包括降水、气温、风速和湿度值）的气象数据集估算地下水补给量。该数据集使用我们的 SURFBAL 代码进行预处理，以计算地表和表土的水和能量平衡。回顾性历史模拟结果表明，三个研究剖面的年平均地下水补给值（49-104 毫米/年）存在相当大的变化。地下水补给的时间变化在所有地点发生相对同步，并受当前年干旱指数变化的控制。这种历史模拟的结果没有揭示过去 30-40 年研究区域地下水补给中的任何气候变化痕迹。为了预测 21 世纪下半叶的补给变化，使用了 LARSWG 预报天气生成器，其中使用了来自耦合模式比对项目 5 (CMIP5) 系列的第 5 环流模式 (GCM) 的气候预测。平均而言，在最大温室气体排放 RCP8.5 情景下的气候发展情况下，2060-2080 年研究区地下水补给量将减少，主要由两个因素造成：一个温暖的季节，在融雪期间积雪和随后的融水渗透。