Dynamic hydrological discharge modelling for coupled climate model simulations of the last glacial cycle: the MPI-DynamicHD model version 3.0
Dynamic hydrological discharge modelling for coupled climate model simulations of the last glacial cycle: the MPI-DynamicHD model version 3.0
复制标题
末次冰期耦合气候模型模拟的动态水文流量建模：MPI-DynamicHD 模型版本 3.0
DOI：
10.5194/gmd-11-4291-2018
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发表时间：
2018
影响因子：
5.1
通讯作者：
U. Mikolajewicz
中科院分区：
文献类型：
--
作者：
T. Riddick;V. Brovkin;S. Hagemann;U. Mikolajewicz
摘要。在上一个冰川周期中，北半球不断演化的大型冰盖通过直接阻塞河流以及冰川均衡调整，对河流路径造成了重大改变。研究表明，这些河流路径的变化通过改变淡水排入海洋的模式，对海洋环流产生了重大影响。因此，对上个冰川周期进行地球系统耦合模型（ESM）模拟需要一个水文排放模型，该模型使用一组随地球地形变化而演变的河流路径，同时能够根据现今地形重现已知的现今河网。在此，我们提出一种动态模拟河流路径的方法，该方法通过在每次重新计算河流流向时对不断演变的精细地形（考虑到变化的冰盖和均衡回弹）应用预定义的校正来满足此类要求。由此产生的校正地形随后被用于创建一组精细的河流路径，然后将这些路径升级到更粗的尺度，在该尺度上，JSBACH陆面模型中现有的现今水文排放模型模拟河流流量。测试表明，该程序能够以足够的精度重现已知的现今河网，并且能够模拟合理的古河网。还表明该程序可以作为瞬态耦合气候模型模拟的一部分成功运行多次。
Abstract. The continually evolving large ice sheets present in the Northern Hemisphere during the last glacial cycle caused significant changes to river pathways both through directly blocking rivers and through glacial isostatic adjustment. Studies have shown these river pathway changes had a significant impact on the ocean circulation through changing the pattern of freshwater discharge into the oceans. A coupled Earth system model (ESM) simulation of the last glacial cycle thus requires a hydrological discharge model that uses a set of river pathways that evolve with Earth's changing orography while being able to reproduce the known present-day river network given the present-day orography. Here, we present a method for dynamically modelling river pathways that meets such requirements by applying predefined corrections to an evolving fine-scale orography (accounting for the changing ice sheets and isostatic rebound) each time the river directions are recalculated. The corrected orography thus produced is then used to create a set of fine-scale river pathways and these are then upscaled to a coarser scale on which an existing present-day hydrological discharge model within the JSBACH land surface model simulates the river flow. Tests show that this procedure reproduces the known present-day river network to a sufficient degree of accuracy and is able to simulate plausible paleo-river networks. It has also been shown this procedure can be run successfully multiple times as part of a transient coupled climate model simulation.