Experimental determination of the nonlinear part of water vapor absorption coefficient in submillimeter transparency windows

1985 ◽  
Vol 28 (6) ◽  
pp. 459-463
Author(s):  
B. A. Sverdlov ◽  
N. I. Furashov
Keyword(s):  
Water Vapor ◽  
Absorption Coefficient ◽  
Experimental Determination ◽  
Water Vapor Absorption ◽  
Nonlinear Part ◽  
Vapor Absorption ◽  
Water Vapor Absorption Coefficient

Photo-acoustic measurements of water vapor absorption coefficient in UV spectral region

1998 ◽  
Vol 7 (3) ◽  
pp. 190-195
Author(s):  
B. A Tikhomirov ◽  
V. O Troitskii ◽  
V. A Kapitanov ◽  
G. S Evtushenko ◽  
Y. N Ponomarev
Keyword(s):  
Water Vapor ◽  
Absorption Coefficient ◽  
Spectral Region ◽  
Acoustic Measurements ◽  
Water Vapor Absorption ◽  
Vapor Absorption ◽  
Water Vapor Absorption Coefficient

scholarly journals A Feasibility Study for Simultaneous Estimates of Water Vapor and Precipitation Parameters Using a Three-Frequency Radar

2005 ◽  
Vol 44 (10) ◽  
pp. 1511-1525 ◽  
Author(s):  
R. Meneghini ◽  
L. Liao ◽  
L. Tian
Keyword(s):  
Water Vapor ◽  
Rayleigh Scattering ◽  
Pulse Compression ◽  
Pulse Repetition Frequency ◽  
Center Frequency ◽  
Water Vapor Absorption ◽  
Single Antenna ◽  
Vapor Absorption ◽  
The Cost ◽  
Lower Frequencies

Abstract The radar return powers from a three-frequency radar, with center frequency at 22.235 GHz and upper and lower frequencies chosen with equal water vapor absorption coefficients, can be used to estimate water vapor density and parameters of the precipitation. A linear combination of differential measurements between the center and lower frequencies on one hand and the upper and lower frequencies on the other provide an estimate of differential water vapor absorption. The coupling between the precipitation and water vapor estimates is generally weak but increases with bandwidth and the amount of non-Rayleigh scattering of the hydrometeors. The coupling leads to biases in the estimates of water vapor absorption that depend primarily on the phase state and the median mass diameter of the hydrometeors. For a down-looking radar, path-averaged estimates of water vapor absorption are possible under rain-free as well as raining conditions by using the surface returns at the three frequencies. Simulations of the water vapor attenuation retrieval show that the largest source of error typically arises from the variance in the measured radar return powers. Although the error can be mitigated by a combination of a high pulse repetition frequency, pulse compression, and averaging in range and time, the radar receiver must be stable over the averaging period. For fractional bandwidths of 20% or less, the potential exists for simultaneous measurements at the three frequencies with a single antenna and transceiver, thereby significantly reducing the cost and mass of the system.

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