Abstract

Visibility has an encompassing importance in humans’ perception of the landscape, since the first encounter with a new environment normally occurs through sight. In historical and archaeological studies, two main methods (i.e., the geometric method and the Geographical Information System [GIS] computation) have been employed to determine the distance from which an object can be recognized. However, neither is exhaustive when applied to a maritime context, where the main factor affecting the visibility radius is weather. To establish how far at sea an object can be seen, and how its visibility would have changed in different weather conditions, we adopted a method from Aerosol Optics based on a well-established mathematical model of the light scattering phenomena. We applied this method to compute the visibility radius in historical studies. To demonstrate its application, we choose to examine the visibility of a key point in both historical and current seafaring, namely Mount Etna (Sicily, Italy), from the Ionian coast of Calabria (Italy). The results obtained by the application of this method have been validated by comparing them with mentions of Mount Etna in both written sources and on-the-ground records.

摘要

能见度在人类对景观的感知中具有包罗万象的重要性，因为与新环境的第一次相遇通常是通过视觉发生的。在历史和考古研究中，已采用两种主要方法（即几何方法和地理信息系统 [GIS] 计算）来确定可以识别物体的距离。然而，当应用于海洋环境时，两者都不是详尽无遗的，其中影响能见度半径的主要因素是天气。为了确定在海上可以看到一个物体的距离，以及它的能见度在不同的天气条件下会如何变化，我们采用了 Aerosol Optics 的一种方法，该方法基于一个完善的光散射现象数学模型。我们应用这种方法来计算历史研究中的能见度半径。为了展示其应用，我们选择从卡拉布里亚（意大利）的爱奥尼亚海岸检查历史和当前航海中的一个关键点，即埃特纳火山（意大利西西里岛）的可见度。通过将应用该方法获得的结果与书面资料和实地记录中提到的埃特纳火山进行比较，验证了该结果。