Apparatus and method for measuring liquid water content of a cloud or fog

Claim 1

An apparatus for measuring liquid water content of a cloud or fog which comprises: environmental chamber means for holding a sample of said cloud under condition of saturation humidity; window means oppositely disposed and axially aligned in said environmental chamber adapted for optical transparency at a critical center wavelength of infrared radiation; fan means operatively disposed in said environmental chamber for maintaining uniformity of droplet concentration therein; valved pipe means for introducing a sample of said cloud into said environmental chamber and permitting a portion of said sample to be withdrawn therefrom for gravimetric measurement; temperature-humidity control means operatively disposed in said environmental chamber for sustaining said sample under saturation humidity; variable optical filter means, operatively disposed exterior to said chamber in axial alignment with said window means, said variable optical filter means providing for an optical bandwidth of approximately 2% of said critical wavelength of infrared radiation; radiation means for generating infrared radiations at said critical wavelength; and scanning radiometer means in axial optical alignment with said variable optical filter means for detecting the refraction and absorption properties of said cloud to said critical wavelength infrared illumination and generating an output signal in response thereto, said output signal being calibrated in grams per cubic meter of liquid water contained in said sample.

Claim 2

An apparatus for measuring liquid water content of a cloud or fog which comprises: environmental chamber means for holding a sample of said cloud under condition of saturation humidity; window means oppositely disposed and axially aligned in said environmental chamber adapted for optical transparency at a critical center wavelength of infrared radiation; fan means operatively disposed in said environmental chamber for maintaining uniformity of droplet concentration therein; valved pipe means for introducing a sample of said cloud into said environmental chamber and permitting a portion of said sample to be withdrawn therefrom for gravimetric measurement; temperature-humidity control means operatively disposed in said environmental chamber for sustaining said sample under saturation humidity; variable optical filter means, operatively disposed exterior to said chamber in axial alignment with said window means, said variable optical filter means providing for an optical bandwidth of approximately 2% of said critical wavelength of infrared radiation; radiation means for generating infrared radiations at said critical wavelength; and scanning radiometer means in axial optical alignment with said variable optical filter means for detecting the refraction and absorption properties of said cloud to said critical wavelength infrared illumination and generating an output signal in response thereto, said output signal being calibrated in grams per cubic meter of liquid water contained in said sample.

Claim 9

A method for measuring the liquid content of a cloud or fog which comprises: positioning a pair of optically transmissive windows in a chamber holding a cloud sample between said optically transmissive windows; optically aligning a spectrally scanning radiometer with a first optical window of said optically transmissive windows; positioning a circular variable filter intermediate said radiometer and said first optical window; optically aligning an infrared energy source in front of a second window of said optically transmissive windows, said infrared source being in axial alignment with said first window, said circular variable filter and said radiometer; preheating said cloud sample to a specified temperature; introducing steam to obtain a cloud sample having a given droplet size and concentration; cooling said cloud sample slowly to sustain saturation humidity; blowing said cloud sample to maintain uniformity of droplet concentration; maintaining said cloud sample at a specified temperature; maintaining said cloud sample at a specified relative humidity; measuring the radiometric emission signals from said cloud sample at a critical infrared wavelength wherein said radiometric emission signals are substantially independent of a droplet size distribution contained in said cloud sample; and calibrating said scanning radiometer to read the total liquid water content of said cloud sample in grams per cubic meter.

Claim 10

A method for measuring the liquid content of a cloud or fog which comprises: positioning a pair of optically transmissive windows in a chamber holding a cloud sample between said optically transmissive windows; optically aligning a spectrally scanning radiometer with a first optical window of said optically transmissive windows; positioning a circular variable filter intermediate said radiometer and said first optical window; optically aligning an infrared energy source in front of a second window of said optically transmissive windows, said infrared source being in axial alignment with said first window, said circular variable filter and said radiometer; preheating said cloud sample to a specified temperature; introducing steam to obtain a cloud sample having a given droplet size and concentration; cooling said cloud sample slowly to sustain saturation humidity; blowing said cloud sample to maintain uniformity of droplet concentration; maintaining said cloud sample at a specified temperature; maintaining said cloud sample at a specified relative humidity; measuring the radiometric emission signals from said cloud sample at a critical infrared wavelength wherein said radiometric emission signals are substantially independent of a droplet size distribution contained in said cloud sample; and calibrating said scanning radiometer to read the total liquid water content of said cloud sample in grams per cubic meter.