Salinization is a well‐known problem in agricultural areas worldwide. In the last 20–30 yr, rising salinity in the upper, unconfined aquifer has been observed in the Freepsumer Meer, a grassland near the German North Sea coast. For investigating long‐term development of salinity and water balance during 1961–2099, the one‐dimensional Soil–Water–Atmosphere–Plant (SWAP) model was set up and calibrated for a soil column in the area. The model setup involves a deep aquifer as the source of salt through upward seepage. In the vertical salt transport equation, dispersion and advection are included. Six different regional outputs of statistical downscaling methods were used as climate scenarios. These comprise different rates of increasing surface temperature and different trends in seasonal rainfall. The simulation results exhibit opposing salinity trends for topsoil and deeper layers. Although projections of some scenarios entail decreasing salinities near the surface, most of them project a rise in subsoil salinity, with the strongest trends of up to +0.9 mg cm−3 100 yr−1 at −65 cm. The results suggest that topsoil salinity trends in the study area are affected by the magnitude of winter rainfall trends, whereas high subsoil salinities correspond to low winter rainfall and high summer temperature. How these projected trends affect the vegetation and thereby future land use will depend on the future management of groundwater levels in the area.

中文翻译：

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模拟不同气候情景下沿海沼泽地未来的盐度动态

盐渍化是世界范围内农业地区的一个众所周知的问题。在过去的 20 至 30 年间，在德国北海沿岸的 Freepsumer Meer 草原上观察到无承压含水层的盐度升高。为了研究 1961-2099 年期间盐度和水平衡的长期发展，建立并校准了该地区土柱的一维土壤 - 水 - 大气 - 植物（SWAP）模型。模型设置涉及一个深层含水层，作为向上渗流的盐源。在盐分垂直输运方程中，包括弥散和平流。统计降尺度方法的六个不同区域输出被用作气候情景。这些包括不同的地表温度上升速率和不同的季节性降雨趋势。模拟结果显示表土和更深层的盐度趋势相反。尽管某些情景的预测需要降低地表附近的盐度，但其中大多数预测底土盐度会升高，-65 cm 处的趋势最强，达到 +0.9 mg cm-3 100 yr-1。结果表明，研究区表土盐度趋势受冬季降雨趋势大小的影响，而高底土盐度对应于冬季降雨量低和夏季温度高。这些预测趋势如何影响植被，从而影响未来的土地利用，将取决于该地区未来地下水位的管理。在 -65 cm 处具有最高 +0.9 mg cm−3 100 yr−1 的最强趋势。结果表明，研究区表土盐度趋势受冬季降雨趋势大小的影响，而高底土盐度对应于冬季降雨量低和夏季温度高。这些预测趋势如何影响植被，从而影响未来的土地利用，将取决于该地区未来地下水位的管理。在 -65 cm 处具有最高 +0.9 mg cm−3 100 yr−1 的最强趋势。结果表明，研究区表土盐度趋势受冬季降雨趋势大小的影响，而高底土盐度对应于冬季降雨量低和夏季温度高。这些预测趋势如何影响植被，从而影响未来的土地利用，将取决于该地区未来地下水位的管理。