Forward-scatter meter for estimating 10.6-microm aerosol extinction

Area of Science:

• Atmospheric optics
• Aerosol science
• Laser-based sensing technologies

Background:

• Aerosols significantly impact climate and visibility.
• Accurate measurement of aerosol properties is essential for atmospheric modeling.
• Existing methods for aerosol characterization have limitations.

Purpose of the Study:

• To evaluate the performance of a forward-scatter meter (FSM) for aerosol characterization.
• To compare FSM measurements with transmissometers operating at visible and infrared wavelengths.
• To determine the FSM's ability to estimate aerosol extinction coefficients.

Main Methods:

• Utilized a forward-scatter meter (FSM) with a He-Ne laser (0.6328 microm).
• Compared FSM data with visible (0.55-microm) and IR (10.6-microm) transmissometers.
• Conducted measurements in hazes and fogs with diverse aerosol size distributions.

Main Results:

• Forward-scatter meter (FSM) showed poor correlation with visible transmissometer measurements.
• FSM measurements demonstrated a strong correlation with aerosol extinction coefficients at 10.6 micrometers.
• Accuracy of scaled FSM measurements to IR extinction coefficient was within +/-10% at 90% confidence.

Conclusions:

• The FSM is not suitable for direct correlation with visible light extinction measurements.
• The FSM can be effectively scaled to provide accurate aerosol extinction coefficients at infrared wavelengths.
• This finding has implications for remote sensing and atmospheric monitoring applications.