Premium
A dual‐wavelength radar technique for measuring the turbulent energy dissipation rate ε
Author(s) -
VanZandt T. E.,
Clark W. L.,
Gage K. S.,
Williams C. R.,
Ecklund W. L.
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2000gl011628
Subject(s) - radar , calibration , environmental science , turbulence kinetic energy , turbulence , meteorology , wavelength , atmospheric sciences , range (aeronautics) , remote sensing , physics , geology , optics , materials science , telecommunications , quantum mechanics , computer science , composite material
We used the ratio of simultaneous observations of radar reflectivity by S‐ and UHF‐band radars together with Hill's model of refractivity fluctuations due to turbulence to infer ε , the rate of viscous dissipation of turbulent kinetic energy per unit mass. Observations were made for 25 days from November 13 to December 7, 1995, at 11.4°S, 130.4°E (about 100 km northwest of Darwin, Australia) during the Maritime Continent Thunderstorm Experiment (MCTEX). The 500 m pulse length data covered the height range 872 to 3032 m MSL. The observed distribution of ε has a strong diurnal variation, with mean daytime and nighttime values of ε of the order of 10 −3 and 10 −5 m²s −3 , respectively. With the dual‐wavelength technique most non‐turbulent echoes (including particulate echoes) are identified and filtered out, since the ensemble of turbulent observations is identified by its conformity to Hill's model. The technique is self‐calibrating, requiring only the relative calibration of the two radars using observations during rain, and does not require precise absolute calibration of either radar.