Determining the Effective Distance of Wind Shelter Index by Defining Innovative Index Named Virtual Wind Shelter in a Non-Snowy Watershed

Abstract

The wind’s effectiveness was compared in different points of a watershed using a quantity called The Wind Shelter Index (WSI). It is necessary to choose a distance called the effective distance in the process of this index calculation. First, the WSI is calculated for different distances, and then the most effective distance is chosen among the different distances. Thus, the WSI corresponding to this distance is determined as the WSI of the region. The current criterion for this purpose (correlation WSI with snow depth) was only usable in snowy places, because it requires measurements of snow depth in different points of the region. According to the wind shelter index usability in some phenomena that are not in snowy areas, the use of this index will be applied. In this study, conducted in the Samsami basin, a new index called “Virtual Wind Shelter index (VWSI)” is introduced that can be used to choose the effective distance of the area applicable in snowy and non-snowy places. It can be seen that using the proposed criterion to select the effective distance doesn’t need to measure snow depth, and this method can be used for non-snow areas. Using the proposed criterion, the WSI corresponding to the 100-meter distance was determined as the WSI of the study area, which was consistent with previous study that was determined by the criterion of correlation of WSI with snow depth in the basin.