The potential of commercial microwave networks to monitor dense fog‐feasibility study

Abstract

[1] Here we show the potential for dense fog monitoring using existing measurements from wireless communication systems. Communication networks widely deploy commercial microwave links across the terrain at ground level. Operating at frequencies of tens of gigahertz, they are affected by fog and are, practically, an existing, sensor network, spatially distributed worldwide, which can provide crucial information about fog concentration and visibility. The goal of this paper is to show the feasibility for fog identification and intensity estimation. A method is proposed and is demonstrated by two cases of heavy fog that took place in Israel. During these events, fog covered wide areas (tens of kilometers) and caused severe decrease in visibility, dropping as low as several tens of meters. Liquid water content and visibility values were estimated using measurements from tens of microwave links deployed in the observed area for each event. Each of the links provided a single measurement which was taken simultaneously across all of the links in the system. The values were found to be in the range of 0.5-0.8 gr/m 3 , high concentration values that match the maximum value range observed in field measurements carried out for prior studies in different test areas in the world. The visibility ranges calculated, between 30 and 70 m, fit the visibility assessments from the specialized measuring equipment operating in the observed area at the same time. These results point to the strong potential of the proposed technique.Citation: David, N., P. Alpert, and H. Messer (2013), The potential of commercial microwave networks to monitor dense fog-feasibility study,

Using Microwave Backhaul Links to Optimize the Performance of Algorithms for Rainfall Estimation and Attenuation Correction

“…In addition to hydrometeors, gaseous components (water vapor and molecular oxygen) and fog (David et al 2013) cause an offset with significant fluctuations of RSL depending on humidity and temperature (Ulaby et al 1981). Furthermore, the accumulation of water or water drops on the microwave link antennas can cause additional wet antenna attenuation that may lead to an overestimation of the attenuation caused by the precipitation along the link path (e.g., Overeem et al 2011;Schleiss et al 2013).…”

Using Cell‐Phone Tower Signals for Detecting the Precursors of Fog

“…Prior research has shown that the attenuation resulting from this phenomenon is of a magnitude around 0.5-1 dB . Figure 12a shows the attenuation caused by atmospheric gases for microwave frequencies up to 40 GHz and Figure 12b the attenuation caused by fog with different liquid water contents, including especially high values above 0.5 gr/m 3 (e.g., David et al, 2013;Gultepe et al, 2009;Niu et al, 2010) for the same range of frequencies.…”

An urban microwave link rainfall measurement campaign

“…The effect of fog on microwave link attenuation has also been observed by e.g. Liebe et al (1989) and David et al (2013). 40 However, it is debatable whether the underlying cause is the wetting of the antennas or the attenuation by the fog droplets themselves.…”

“…Several possible sources of error have been identified previously: the wet antenna effect and related dew formation on antennas (Minda & Nakamura, 2005;Leijnse, et 30 al., 2008), humidity and temperature (Minda & Nakamura, 2005), solid precipitation and spatial variability of precipitation (Berne & Uijlenhoet, 2007). Opportunities for simultaneous measurement of other environmental variables than rainfall have also been identified, such as evaporation (Leijnse, et al, 2007b), fog (Liebe, et al, 1989;David, et al, 2013), humidity (Chwala, et al, 2014) and hydrometeor type (Cherkassky, et al, 2014).…”