This study investigates the spatial structure and the seasonal occurrence of foehn wind to the east of the Andes using a flow blocking analysis in a 20-year climate simulation. The latter was performed by the Eta-CPTEC regional model at 50-km horizontal resolution. This version of the model includes a cut-cell scheme to represent topography and a finite-volume vertical advection scheme for dynamic variables. The results indicate that foehn wind more frequently blows during winter and spring on the eastern slopes of the Andes, except to the south of 37° S where it blows at all seasons. Higher mountains of the Central Andes (27° S–35° S) and the High Plateau (15° S–27° S) result in blocked foehn events, with a weak adjustment to the geostrophic balance. On the Central Andes, rain and snow on mountain tops may also contribute to generate foehn wind on the eastern slopes. The results show that a low pressure develops to the east of the Central Andes, and also to the east of the High Plateau when foehn blows. Lower mountains in Patagonia (to the south of 37° S) result in more frequent non-blocked foehn event, with better adjustment to the geostrophic balance.

中文翻译：

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20 年气候模拟中安第斯山脉以东的焚风

本研究使用流动阻塞分析在 20 年气候模拟中研究了安第斯山脉以东焚风的空间结构和季节性发生。后者由 Eta-CPTEC 区域模型以 50 公里水平分辨率执行。此版本的模型包括表示地形的切割单元方案和用于动态变量的有限体积垂直平流方案。结果表明，除南纬 37 度以南地区全年吹风外，安第斯山脉东坡的焚风在冬春季节吹得更频繁。中部安第斯山脉 (27° S–35° S) 和高原 (15° S–27° S) 的较高山脉导致焚风事件受阻，对地转平衡的调整较弱。在安第斯山脉中部，山顶的雨雪也可能导致东坡产生焚风。结果表明，当焚风吹来时，中部安第斯山脉以东和高原以东形成低压。巴塔哥尼亚的低山（南纬 37°以南）导致非阻塞焚风事件更频繁，对地转平衡有更好的调整。