Simulating the evolution of the topography-climate coupled system

Abstract

Abstract. Landscape evolution models simulate the long-term variation of topography under given rainfall scenarios. In reality, local rainfall is largely affected by topography, implying that surface topography and local climate evolve together. Herein, we develop a numerical simulation model for the evolution of the topography-climate coupled system. We investigate how simulated topography and rain field vary between no-feedback and co-evolution simulations. Co-evolution simulations produced results significantly different from those of no-feedback simulations, as illustrated by transects and time evolution in rainfall excess among others. We show that the evolving system keeps climatic and geomorphic footprints in asymmetric transects and local relief. We investigate the roles of the wind speed and the time lags between hydrometeor formation and rainfall (called the delay time) in the co-evolution. While effects of the wind speed and delay time were thought to compensate each other in the evolving morphology, we demonstrate that the evolution of the coupled system can be more complicated than previously thought. The channel concavity on the windward side becomes lower as the imposed wind speed or the delay time grows. This tendency is explained with the effect of generated spatial rainfall distribution on the area-runoff relationship.

Influence of orographic precipitation on coevolving landforms and vegetation in semi‐arid ecosystems

“…erosion equals tectonic uplift). These results are consistent with those from previous modelling studies (Anders et al, 2008; Goren et al, 2014; Han et al, 2015; Paik & Kim, 2021; Zavala et al, 2020). The results for divide migration for bare soil conditions are also in agreement with results from previous studies (Anders et al, 2008; Bonnet, 2009), in which the windward side of the domain is found to be gentler for low contributing areas (such as those in the divide), and the drainage divide is displaced from the centre of the domain towards the leeward side (Anders et al, 2008; Bonnet, 2009; Giachetta et al, 2014).…”

“…Numerical simulations conducted by Goren et al (2014) investigated the effects of orographic controls on landform evolution under constant uplift and no vegetation cover, revealing that windward slopes are longer and gentler than the leeward ones due to the presence of enhanced erosion induced by higher runoff. A key aspect missing from these previous landscape evolution studies is, however, the effect of coevolving landform–vegetation patterns under orographic precipitation conditions, and their possible implications for landform asymmetry (Paik & Kim, 2021; Smith & Bookhagen, 2021; Zavala et al, 2020).…”

“…The study conducted by Goren et al (2014) with a LEM showed that the windward side is longer than the leeward side of the mountain because higher rainfall and higher erosion rates generate a gentler slope on the windward side. Further modelling work by Paik and Kim (2021) to understand topographic asymmetry showed that the windward side receives more rainfall and so produces more runoff and sediment yield than the leeward side. As a result, the channels on the windward side propagate upstream at a faster rate, compared to those on the leeward side, which leads to a downward peak migration and a steeper slope.…”

The linear feedback precipitation model (LFPM 1.0) – a simple and efficient model for orographic precipitation in the context of landform evolution modeling

“…The redistribution of moisture from the oceans towards continental domains governs the global erosion engine. Spatial variability in precipitation and hence in the availability of water or ice as principal agents of erosion controls the shape of landforms (e.g., Ellis et al, 1999;Willett, 1999;Anders et al, 2008;Bonnet, 2009;Menking et al, 2013;Colberg and Anders, 2014;Goren et al, 2014;Chen et al, 2019;Han et al, 2015;Paik and Kim, 2021). However, feedbacks between topography, precipitation, and erosion may even make it difficult to distinguish between cause and effect (Molnar and England, 1990).…”

“…It seems that the model of Smith and Barstad (2004) (SB model in the following) received the most attention from the landform evolution modeling community among these models. It was adopted by some other authors in the context of co-evolution of topography and climate (e.g., Anders et al, 2008;Han et al, 2015;Paik and Kim, 2021), although the model of Garcia-Castellanos (2007) has some advantages (see Sect. 6).…”