Final answer:
The relative humidity at sea level cannot be calculated directly from the options A, B, C, or D provided. The actual method involves using psychrometric charts or formulas that apply thermodynamic principles to the dry-bulb and wet-bulb temperature readings to find vapor densities and then calculating the relative humidity.
Step-by-step explanation:
To calculate the relative humidity (rh) at sea level from the measured dry-bulb temperature (tdb) and wet-bulb temperature (twb), we'll need additional psychrometric calculations that involve using both of these temperatures to determine the moisture content of the air and comparing it to the moisture content at saturation.
None of the options A, B, C, or D directly indicate the correct method for determining relative humidity. Instead, relative humidity can be calculated using tables or formulas derived from the psychrometric equations, which account for the principles of thermodynamics pertaining to moist air.
For example, the formula for the percent relative humidity is as follows:
percent relative humidity = ( actual vapor density / saturation vapor density ) x 100
In our context, to find the actual vapor density, you could use the dry-bulb and wet-bulb temperatures in conjunction with psychrometric charts or equations that apply the psychrometric principles. To use such charts or equations, you generally need more complex relations that account for the cooling effect of evaporation at the wet-bulb, the pressure of water vapor in the air, and the temperature of the air.
This is beyond the scope of the answer choices given. The saturation vapor density would depend on the dry-bulb temperature and can be found in tables or calculated using equations for the saturation pressure of water vapor at that particular temperature.