Wind variability and Earth’s rotation as drivers of transport in a deep, elongated subalpine lake: The case of Lake Garda

Drivers of transport in Lake Garda

Abstract

The effects of wind forcing and Earth’s rotation on the transport processes in Lake Garda, Italy, are investigated for the first time under different thermal stratification conditions and typical diurnal wind cycles. Numerical simulations are performed by means of a modeling chain composed of a meteorological (WRF) and a hydrodynamic (Delft3D) model. Transport processes are studied through the combined analysis of the residual (time averaged) flow field and the trajectories of Lagrangian particles. Results show that strong currents develop in winter under the forcing of synoptic northerly Föhn winds, especially in the elongated northern region, where winds are channeled by the steep orography. Significant water volumes are displaced laterally by Ekman transport, producing intense downwelling and upwelling along the steep shores. Instead summer patterns are controlled by the diurnal cycle of local breezes, alternately blowing along the main axis of the lake. The resulting circulation reveals counterclockwise gyres in the northern part, driven by the alternating wind direction and affected by Coriolis force. The analysis suggests that complex circulations can develop in lakes with relatively simple geometries, like the narrow trunk region of Lake Garda, where the effect of Earth’s rotation unexpectedly influences the transport patterns.

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Author Biography

Marina Amadori, University of Trento, Department of Civil, Environmental and Mechanical Engineering
Marina Amador is a PhD student at the University of Trento (Italy), Department of Civil, Environmental and Mechanical Engineering. She does research in physical limnology in a doctorate study on Lake Garda, Italy. Her research concerns the development of a coupled atmospheric and hydrodynamic model and the investigation of transport processes in Lake Garda. 
Published
2018-09-11
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Original Articles
Keywords:
Lake circulation, atmosphere-lake numerical modeling, deep lakes, transport processes.
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How to Cite
1.
Amadori M, Piccolroaz S, Giovannini L, Zardi D, Toffolon M. Wind variability and Earth’s rotation as drivers of transport in a deep, elongated subalpine lake: The case of Lake Garda: Drivers of transport in Lake Garda. J Limnol [Internet]. 2018Sep.11 [cited 2021May13];77(3). Available from: https://jlimnol.it/index.php/jlimnol/article/view/jlimnol.2018.1814