scholarly journals Simulating the evolution of the topography–climate coupled system

2021 ◽  
Vol 25 (5) ◽  
pp. 2459-2474
Author(s):  
Kyungrock Paik ◽  
Won Kim
Keyword(s):  
Wind Speed ◽  
Delay Time ◽  
Coupled System ◽  
Windward Side ◽  
Time Lags ◽  
Local Climate ◽  
Term Variation ◽  
Evolving System ◽  
Local Relief

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 their combined effects were thought to be represented by the non-dimensional delay time, 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.

scholarly journals Simulating the evolution of the topography-climate coupled system

2020 ◽  
Author(s):  
Kyungrock Paik ◽  
Won Kim
Keyword(s):  
Wind Speed ◽  
Delay Time ◽  
Coupled System ◽  
Windward Side ◽  
Time Lags ◽  
Local Climate ◽  
Term Variation ◽  
Evolving System ◽  
Local Relief

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.

scholarly journals Topoclimatological case-study of Alpine pastures near the Albula Pass in the eastern Swiss Alps

2013 ◽  
Vol 68 (4) ◽  
pp. 249-263 ◽  
Author(s):  
P. Michna ◽  
W. Eugster ◽  
R. V. Hiller ◽  
M. J. Zeeman ◽  
H. Wanner
Keyword(s):  
Climate Change ◽  
Wind Speed ◽  
Farming System ◽  
Swiss Alps ◽  
Plant Production ◽  
Small Scale ◽  
Research Station ◽  
Near Surface ◽  
Local Climate

Abstract. Alpine grasslands are an important source of fodder for the cattle of Alpine farmers. Only during the short summer season can these pastures be used for grazing. With the anticipated climate change, it is likely that plant production – and thus the fodder basis for the cattle – will be influenced. Investigating the dependence of biomass production on topoclimatic factors will allow us to better understand how anticipated climate change may influence this traditional Alpine farming system. Because small-scale topoclimatological variations of the main meteorological variables: temperature, humidity, precipitation, shortwave incoming radiation and wind speed are not easily derived from available long-term climate stations in mountainous terrain, it was our goal to investigate the topoclimatic variations over the pastures belonging to the Alp Weissenstein research station north of the Albula Pass in the eastern Swiss Alps. We present a basic assessment of current topoclimatic conditions as a site characterization for ongoing ecological climate change studies. To be able to link short-term studies with long-term climate records, we related agrometeorological measurements with those of surrounding long-term sites run by MeteoSwiss, both on valley bottoms (Davos, Samedan), and on mountain tops (Weissfluhjoch, Piz Corvatsch). We found that the Davos climate station north of the study area is most closely correlated with the local climate of Alp Weissenstein, although a much closer site (Samedan) exists on the other side of the Albula Pass. Mountain top stations, however, did not provide a convincing approximation for the climate at Alp Weissenstein. Direct comparisons of near-surface measurements from a set of 11 small weather stations distributed over the domain where cattle and sheep are grazed indicate that nocturnal minimum air temperature and minimum vapor pressure deficit are mostly governed by the altitudinal gradient, whereas daily maxima – including also wind speed – are more strongly depending on vegetation cover and less on the altitude.

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