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Effects of humidity and precipitation on VHF radar vertical beam echoes
Author(s) -
Vaughan G.,
Worthington R. M.
Publication year - 2000
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/1999rs002260
Subject(s) - humidity , precipitation , radar , relative humidity , environmental science , atmospheric sciences , meteorology , apparent temperature , water vapor , air humidity , remote sensing , materials science , geology , physics , telecommunications , computer science
We investigate in this paper the variation in power of VHF radar vertical echoes as a function of atmospheric humidity. We find that the echoes are greatest in air of moderate (30–70%) humidity, and least in very dry or near‐saturated air. Compared to moderate humidities, the standard model for radar echoes, based on potential refractivity, overpredicts the echo power at high relative humidity by ∼10 dB. We propose that this is due to the effect of precipitation in suppressing small‐scale humidity gradients. A model which assumes complete suppression underpredicts the observed power drastically, showing that precipitation can only remove a part of the small‐scale structure in refractivity which is caused by fluctuations in humidity.