The Bowen ratio is calculated by the equation:

B = Q h Q e {\displaystyle B={\frac {Q_{h}}{Q_{e}}}} 📷, where Q h {\displaystyle Q_{h}} 📷 is sensible heating and Q e {\displaystyle Q_{e}} 📷 is latent heating.

In this context, when the magnitude of B {\displaystyle B} 📷 is less than one, a greater proportion of the available energy at the surface is passed to the atmosphere as latent heat than as sensible heat, and the converse is true for values of B {\displaystyle B} 📷 greater than one. As Q e → 0 {\displaystyle {Q_{e}\rightarrow 0}} 📷, however, B {\displaystyle B} 📷 becomes unbounded making the Bowen ratio a poor choice of variable for use in formulae, especially for arid surfaces. For this reason, the evaporative fraction is sometimes a more appropriate choice of the variable representing the relative contributions of the turbulent energy fluxes to the surface energy budget.

The Bowen ratio is related to the evaporative fraction, E F {\displaystyle EF} 📷, through the equation,

E F = Q e Q e + Q h = 1 1 + B {\displaystyle {EF={\frac {Q_{e}}{Q_{e}+Q_{h}}}={\frac {1}{1+B}}}} 📷.

The Bowen ratio is an indicator of the type of surface. The Bowen ratio, B {\displaystyle {B}} 📷, is less than one over surfaces with abundant water supplies.

Article Calculation of the Bowen ratio in the tropical Pacific using...

The ratio of sensible to latent heat fluxes at the surface is called the Bowen ratio6: B = FHs/FEs. Due to the nonlinearity inherent in the Clausius-Clapeyron equation, the Bowen ratio over the oceans decreases with increasing sea surface temperature.

The following link may help

www.atmos.washington.edu › ...PDF

Lecture 14 - Science of Climate

@Atiqe Ur Rahman, the link is dead.

Dear Amor,

One of the most widely used methods to determine the evaporative flux from the earth surface is the Bowen Ratio Energy Balance method (BREB). The BREB requires sensors to determine net radiation, soil heat flux density at the soil surface, and gradients of air temperature and vapor pressure. So here are some of the links to calculate step by step the variables of BREB:

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/bowen-ratio

https://link.springer.com/article/10.1007%2FBF00821549

Article Validating Evapotranspiraiton Equations Using Bowen Ratio in...

https://daac.ornl.gov/FIFE/Datasets/Surface_Flux/Bowen_Ratio_USGS.html

Article Evaluation of the Bowen ratio/energy balance method for dete...

https://www.diva-portal.org/smash/get/diva2:946508/FULLTEXT01.pdf

I hope it helps.

Thanks

Ankur

Article Calculation of the Bowen ratio in the tropical Pacific using...