A rain height model to predict fading due to wet snow on terrestrial links

Paulson, K.; Al-Mreri, A.

Abstract

Recommendation ITU‐R P.530‐13 provides an internationally recognized prediction model for the fading due to wet snow on low‐elevation, terrestrial microwave links. An important parameter in this model is the altitude difference between the link and the rain height. The top of rain events is usually assumed to be 360 m above the zero‐degreeisotherm (ZDI). Above this height, hydrometeors are ice with low specific attenuation. Below this level, melting ice particles produce a specific attenuation up to 4 times that of the associated rain rate. A previous paper identified increasing ZDI height trends across northern Europe, North America and central Asia with slopes up to 10 m/yr. This paper examines NOAA National Centers for Environmental Prediction-National Center for Atmospheric Research Reanalysis 1 data to identify global distributions of ZDI height around mean levels that increase linearly over time. The average annual distribution of ZDI heights relative to the annual mean are calculated for each NOAA Reanalysis grid square and skew normal distributions are fitted. These are compared to models in Recommendation ITU‐R P.530‐13 and Recommendation ITU‐R 452‐14. The effects of ZDI trends and the calculated skew normal distributions are illustrated using calculated trends in fading due to wet snow for two notional 38 GHz links in Edinburgh. A slow decrease in the incidence of fading due to wet snow is predicted over most of Europe. However, some links could experience increases where warming has increased the wetness of snow.

Citation

Paulson, K., & Al-Mreri, A. (2011). A rain height model to predict fading due to wet snow on terrestrial links. Radio science, 46(4), Article RS4010. https://doi.org/10.1029/2010rs004555

• Journal Article Type: Article
• Acceptance Date: May 12, 2011
• Online Publication Date: Aug 27, 2011
• Publication Date: Sep 7, 2011
• Deposit Date: Nov 13, 2014
• Publicly Available Date: Nov 13, 2014
• Journal: Radio science
• Print ISSN: 0048-6604
• Publisher: American Geophysical Union
• Peer Reviewed: Peer Reviewed
• Volume: 46
• Issue: 4
• Article Number: RS4010
• DOI: https://doi.org/10.1029/2010rs004555
• Keywords: Climate change; Fading; Rain height; Sleet; Wet snow; Zero degree isotherm
• Public URL: https://hull-repository.worktribe.com/output/463186
• Publisher URL: http://onlinelibrary.wiley.com/doi/10.1029/2010RS004555/pdf
• Additional Information: Copy of article first published in Radio science, 2011, v.46, issue 4
• Contract Date: Nov 13, 2014