Prediction of rainfall intensity measurement errors using commercial microwave communication links
Open Access
- 12 October 2010
- journal article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 3 (5), 1385-1402
- https://doi.org/10.5194/amt-3-1385-2010
Abstract
Commercial microwave radio links forming cellular communication networks are known to be a valuable instrument for measuring near-surface rainfall. However, operational communication links are more uncertain relatively to the dedicated installations since their geometry and frequencies are optimized for high communication performance rather than observing rainfall. Quantification of the uncertainties for measurements that are non-optimal in the first place is essential to assure usability of the data. In this work we address modeling of instrumental impairments, i.e. signal variability due to antenna wetting, baseline attenuation uncertainty and digital quantization, as well as environmental ones, i.e. variability of drop size distribution along a link affecting accuracy of path-averaged rainfall measurement and spatial variability of rainfall in the link's neighborhood affecting the accuracy of rainfall estimation out of the link path. Expressions for root mean squared error (RMSE) for estimates of path-averaged and point rainfall have been derived. To verify the RMSE expressions quantitatively, path-averaged measurements from 21 operational communication links in 12 different locations have been compared to records of five nearby rain gauges over three rainstorm events. The experiments show that the prediction accuracy is above 90% for temporal accumulation less than 30 min and lowers for longer accumulation intervals. Spatial variability in the vicinity of the link, baseline attenuation uncertainty and, possibly, suboptimality of wet antenna attenuation model are the major sources of link-gauge discrepancies. In addition, the dependence of the optimal coefficients of a conventional wet antenna attenuation model on spatial rainfall variability and, accordingly, link length has been shown. The expressions for RMSE of the path-averaged rainfall estimates can be useful for integration of measurements from multiple heterogeneous links into data assimilation algorithms.Keywords
This publication has 23 references indexed in Scilit:
- Rain Rate Estimation Using Measurements From Commercial Telecommunications LinksIEEE Transactions on Signal Processing, 2009
- Technical Note: Novel method for water vapor monitoring using wireless communication networks measurementsPublished by Copernicus GmbH ,2008
- A weighted total least-squares algorithm for fitting a straight lineMeasurement Science and Technology, 2007
- Combined use of point rain gauges, radar, microwave link and level measurements in urban hydrological modellingAtmospheric Research, 2005
- Comparison of the use of dual-frequency and single-frequency attenuation for the measurement of path-averaged rainfall along a microwave linkIEE Proceedings - Microwaves, Antennas and Propagation, 2003
- Relationships between rainfall rate and 35-GHz attenuation and differential attenuation: modeling the effects of raindrop size distribution, canting, and oscillationIEEE Transactions on Geoscience and Remote Sensing, 2002
- Effect of wet antenna attenuation on propagation data statisticsIEEE Transactions on Antennas and Propagation, 2001
- A Comparison of Microwave Techniques for Measuring RainfallJournal of Applied Meteorology and Climatology, 1991
- The Lognormal Fit to Raindrop Spectra from Frontal Convective Clouds in IsraelJournal of Climate and Applied Meteorology, 1986
- Path- and Area-Integrated Rainfall Measurement by Microwave Attenuation in the 1–3 cm BandJournal of Applied Meteorology, 1977