Chapter 7, Problem 31P

The dew point temperature T_dand the relative humidity RH can be calculated (approximately) from the dry-bulb T and wet-bulb T_wtemperatures by (http//www.wikipedia.org):

$e_s=6.112\exp \left(\frac{17.67T}{T+243.5}\right)$ $e_w=6.112\exp \left(\frac{17.67T_w}{T_w+243.5}\right)$

e = e_w− P_sta(T − T_w)0.00066(1 + 0.00115T_w)

$RH=100\frac{e}{e_s}{T}_d=\frac{243.5\text{In}(e/6.112)}{17.67-\text{In}(e/6.112)}$

where the temperatures are in degrees Celsius, RH is in %, and p_stais the barometric pressure in units of millibars.

Write a user-defined MATLAB function that calculates the dew point temperature and relative humidity for given dry-bulb and wet-bulb temperatures in degrees Fahrenheit (° F) and barometric pressure in inches of mercury (inHg). For the function name and arguments, use [Td, RH) = DewptRhum (T, Tw, BP), where the input arguments T, Tw, BP are dry-bulb and wet-bulb temperatures in °F and BP is the barometric pressure in inHg, respectively. The output arguments Td, RH are the dew point temperature in °F and the relative humidity in %. The values of the output arguments should be rounded to the nearest tenth. Use anonymous function or subfunctions inside DewptRhum to convert units.

Use the user-defined function DewptRhum for calculating the dew point temperature and relative humidity for the following cases:

(a) T = 78 °F, T_w= 66 °F, p_sta= 29.09 inHg

(b) T= 97 °F, T_w= 88 °F, p_sta= 30.12 mbar