Urban moisture based on commercial microwave links (CML) data and relation to land-cover – case of Tel- Aviv metropolitan area

The near-surface humidity is a crucial variable in many atmospheric processes, mostly in those related to development of clouds and rain. The humidity at the height of a few tens of meters above surface is highly influenced by the surface characteristics. In many cases the land-cover (LC) is responsible for the spatial variation of the surface humidity field, therefore, it is a major factor in determining the conditions for rainfall. Cities are one of the primary LCs which have a substantial impact on the humidity field. Large urban areas are expanding, causing a significant change in the near-surface humidity field. Measuring the near-surface humidity in high resolution, where most of the humidity’s sinks and sources are, is challenging with the common tools available today. Current measurement tools do not satisfactorily assess the cities’ effects on the humidity field. A new approach for measuring the humidity, based on the cellular network, provides high resolution information on the near-surface humidity. Therefore, we can examine the land-cover effect on the humidity in the low atmosphere in fine scale. In this study, the humidity field around Tel Aviv was retrieved from the cellular network during the summer of 2017. The results show a well-noticed impact of the city and other LC types on the humidity field over the Tel Aviv metropolitan area. The method presented here can offer an improved description of the humidity field at the city-canopy level and therefore provide a better assessment of the urban/LC effects on the environment, atmospheric modeling, and particularly on clouds/rain development.