Quantification of surface layer turbulence using sensible heat values from energy balance versus aerodynamic methods

Area of Science:

• Atmospheric science
• Optical turbulence
• Surface layer meteorology

Background:

• Optical turbulence (Cn2) is often derived from surface layer atmospheric properties.
• Sensible heat is a critical component for Cn2 calculations.
• Traditional bulk aerodynamic methods for sensible heat have limitations, particularly outside free convection conditions.

Purpose of the Study:

• To compare the accuracy of Cn2 calculations using sensible heat derived from the bulk aerodynamic method versus the energy balance (Bowen ratio) method.
• To evaluate the reliability and simplicity of different methods for calculating surface layer sensible heat flux.
• To assess the impact of sensible heat calculation methods on optical turbulence estimations.

Main Methods:

• Calculated surface layer refractive index structure function (Cn2) values.
• Determined sensible heat flux using both the bulk aerodynamic method and the energy balance (Bowen ratio) method.
• Compared calculated Cn2 values with measurements from sonic anemometers at various heights.

Main Results:

• Sensible heat derived from the Bowen ratio method yielded simpler, more reliable, and accurate surface layer Cn2 values.
• The bulk aerodynamic method's assumptions proved less suitable for Cn2 calculations under varying conditions.
• Direct assessment of optical turbulence-driving sensible heat flux is more effective using the Bowen ratio.

Conclusions:

• The Bowen ratio method is superior to the bulk aerodynamic method for calculating sensible heat flux relevant to optical turbulence.
• Accurate sensible heat flux determination is crucial for precise optical turbulence (Cn2) estimations.
• This study highlights a more robust approach for atmospheric optical turbulence research.