Technical Note: Novel method for water vapour monitoring using wireless communication networks measurements
- ISSN: 1680-7324
- DOI: 10.5194/acp-9-2413-2009
We propose a new technique that overcomes the obstacles of the existing\nmethods for monitoring near-surface water vapour, by estimating humidity\nfrom data collected through existing wireless communication networks.\nWeather conditions and atmospheric phenomena affect the electromagnetic\nchannel, causing attenuations to the radio signals. Thus, wireless\ncommunication networks are in effect built-in environmental monitoring\nfacilities. The wireless microwave links, used in these networks, are\nwidely deployed by cellular providers for backhaul communication between\nbase stations, a few tens of meters above ground level. As a result, if\nall available measurements are used, the proposed method can provide\nmoisture observations with high spatial resolution and potentially high\ntemporal resolution. Further, the implementation cost is minimal, since\nthe data used are already collected and saved by the cellular operators.\nIn addition-many of these links are installed in areas where access is\ndifficult such as orographic terrain and complex topography. As such,\nour method enables measurements in places that have been hard to measure\nin the past, or have never been measured before. The technique is\nrestricted to weather conditions which exclude rain, fog or clouds along\nthe propagation path. Strong winds that may cause movement of the link\ntransmitter or receiver (or both) may also interfere with the ability to\nconduct accurate measurements. We present results from real-data\nmeasurements taken from two microwave links used in a backhaul cellular\nnetwork that show convincing correlation to surface station humidity\nmeasurements. The measurements were taken daily in two sites, one in\nnorthern Israel (28 measurements), the other in central Israel (29\nmeasurements). The correlation between the microwave link measurements\nand the humidity gauges were 0.9 and 0.82 for the north and central\nsites, respectively. The Root Mean Square Differences (RMSD) were 1.8\ng/m(3) and 3.4 g/m(3) for the northern and central site measurements,\nrespectively.