Peter F. Germann

Dear Editor:

I am sad to report that Peter Germann died on 6 Dec. 2020 in Bern, Switzerland. Peter was well known to many soil hydrologists for his work on preferential flows—a career of research work that was summarized in his 2013 book on the subject published by the University of Bern (Germann, 2013). Peter had been a good friend since we first met at the Institute of Hydrology at Wallingford in 1979, where he spent a year as a post‐doc and we found we had a common interest in preferential flows.

Peter was born in St. Gallen Switzerland in 1944. He grew up in Bischofszell and later completed his schooling in St. Gallen. In 1963–1969, he studied for a Degree in Forestry at ETH Zurich and then stayed with Professor Richard to carry out research for a PhD at the Eidgenössische Forschungsanstalt für Wald, Schnee und Landschaft (WSL) from 1969 to 1976. He continued his work in the Laboratories of Hydraulics, Glaciology and Hydrology (VAW) during the period of 1976–1980. His PhD work was a study of the water relations on a forested slope in the Rietholzbach catchment based on maintaining a network of 35 nests of tensiometers at 10 different depths down to 3 m, set out on a triangular grid amongst the trees. At this time, these were still manual tensiometers coupled to mercury manometers that were read every two to three days for three years. One of the features that this remarkable dataset revealed was that during infiltration wetting could occur at depth in some cases, apparently bypassing the tensiometers above. Another was the large heterogeneity in responses between sites and between wetting events.

Peter returned to Switzerland from Wallingford, and then in 1980 he took up a post as Assistant Professor in the Department of Environmental Sciences at the University of Virginia in Charlottesville where he stayed until 1986. He then moved as an Associate Professor to the Department of Soils and Crops at Rutgers University. In 1989, he was offered a Professorship at the Institute of Geography, University of Bern, back in Switzerland where he stayed until he retired in 2009. He held an Emeritus position at Bern until 2015. He continued to publish papers until shortly before his death, which followed two major strokes.

For the major part of his research career, Peter was a strong advocate for a reconsideration of the physics of water flow through soils and, in particular, for the limitations of the Darcy–Buckingham–Richards flow theory that is based on an assumption of the equilibration of capillary potentials in some (not clearly defined) “representative elementary volume” of soil pores. Our common interested resulted in the highly cited review paper in Water Resources Research on macropores and water flow in soils in 1982 (later revisited in 2013), and a sequence of three papers in the Journal of Soil Science including a modeling approach based on kinematic wave theory that received very critical reviews. Some soil physicists at that time appeared to believe that the physics of soil physics had been solved. Peter later developed the kinematic wave approach into a theory of viscosity (rather than capillarity) dominated film flows subject to Stokes’ law during infiltration. Peter was a careful experimentalist, both in the laboratory and in the field, and made use of a variety of time domain reflectometry, sonic, and tracer experiments to study preferential flows. His thoughtful and good humored approach to collaborations, discussions, and presentations will be missed by many in soil science.

彼得·F·德国

亲爱的编辑：

我伤心地报告，彼得GERMANN于2020年12月6日在瑞士伯尔尼死亡。彼得因其在优先流量方面的工作而在许多土壤水文学家中广为人知。他的研究工作在伯尔尼大学于2013年出版的关于该主题的书中得到了概述（Germann，2013年）。自从我们于1979年在沃灵福德水文研究所首次见面以来，彼得就一直是好朋友，在那里他花了一年的时间从​​事博士后工作，我们发现我们对优惠水流有着共同的兴趣。

彼得1944年出生于瑞士圣加仑。他在比绍夫策尔长大，后来在圣加仑完成了学业。在1963年至1969年间，他在苏黎世联邦理工学院攻读林业学位，然后与理查德教授呆在一起，在1969年至1976年间，在Schnee und Landschaft的EidgenössischeForschungsanstaltfürWald（WSL）从事博士学位研究。他继续他的工作。 1976年至1980年期间在水力学，冰川学和水文学实验室（VAW）工作。他的博士学位研究是对Rietholzbach集水区森林斜坡上水关系的研究，其基础是在树木之间的三角形网格上，在10个不同深度（至3 m）上保持35个张力计巢的网络。目前，这些仍然是手动张力计，与汞压力计耦合在一起，可每三年两到三天读取一次。这个非凡的数据集揭示的特征之一是，在渗透过程中，某些情况下润湿可能发生在深度处，显然绕过了上面的张力计。另一个是站点之间和润湿事件之间响应的巨大异质性。

彼得从沃灵福德（Wallingford）返回瑞士，然后在1980年担任夏洛茨维尔弗吉尼亚大学环境科学系的助理教授，一直待到1986年。然后他作为土壤系的副教授搬到了那里。和罗格斯大学的农作物。1989年，他在瑞士的伯尔尼大学地理学院获得教授职位，直到2009年退休为止。他一直在瑞士任职。直到2015年，他一直在伯尔尼担任名誉职位。直到他去世前不久，他一直发表论文。 ，此后有两个主要笔画。

在他的研究生涯的大部分时间里，彼得大力倡导重新考虑流经土壤的水流物理学，尤其是对于达西-白金汉-理查兹流理论的局限性，该理论基于对水的假设。在某些（未明确定义）土壤孔隙的“代表性基本体积”中毛细管电势的平衡。我们共同的兴趣是在1982年发表的《水资源研究中土壤中的大孔和水流》（后来于2013年重新审视）中被高引用的评论论文，以及《土壤科学》杂志上的三篇论文的连载包括基于运动波理论的建模方法，该方法获得了非常严格的评价。当时的一些土壤物理学家似乎认为土壤物理学已经解决。后来，彼得将运动波方法发展为一种以粘度（而不是毛细作用）为主导的薄膜流理论，该理论受渗透过程中斯托克斯定律的约束。彼得在实验室和现场都是认真的实验学家，并利用各种时域反射仪，声波和示踪剂实验来研究优先流量。土壤科学领域的许多人会怀念他对协作，讨论和演讲的体贴和幽默的态度。