The Clausius-Clapeyron (CC) equation describes the relationship between temperature T and saturation vapor pressure es​ :
eₛ=eₒexp[​L/Rv​(1/Tₒ−1/T​)],
where eₒ​=0.611kPa and T0​=273 K are constant parameters. Rᵥ​=461 J K⁻¹ kg⁻¹ is the gas constant for water vapor. For water droplets, use the latent heat of vaporization L= Lᵥ=2.5×10⁶ J kg⁻¹
Use the CC equation to derive an equation for the dew-point temperature Td​ as a function of vapor pressure e.
The mixing ration r (in gvapor ​/gdry air ​ ) is related to the water vapor pressure e by r=εe/P-e​.
where ε=Rd​/Rv​=0.622 g vapor /gdry air ​ is the ratio of gas constants for dry air to that for water vapor. P is the full atmospheric pressure.
Given a mixing ratio r=0.01 g/g, what is the vapor pressure e at seal level (1013hPa) ?