Question

41.9 39.7 37.6 35.5 33.4 31.4 29.6 27.8 26.1 24.6 23.2 21.8 20.5 19.2 -18.0 16.9 U 15.8 14.8 13.9 13.0 12.2 MWWW WWWWWWYWDEO 2.5 13.0 2.0 WANN W 11.5 WWW WWWWWWWW 11.0 10.11.0" B WWWWWWWWWWWWWWWWWWWWWI 10.0 -10 + 9.5 WO -15 Dry Bulb (°C) COGNO. SO UNO-NAU CONWONNEN Saturation Vapour Pressure NIMIWWWWWWWWWWW NI NANIWANI WIMMAMMANI MAXWWW MANY WIMWWWW MWWWWW -25 20 Wet Bulb Depression (°C) 4.7 4.3 4.0 3.8 XA 3.5 3.2 2.9 2.6 2.4 2.2 2.0 1.8 1.7 1.5 1.4 1.3 1.1 FAAN 2.5 -19 Toc = (Top – 32) 2.0 G] 1.0 -20 temperature ras 0.5 1.0 Relative hr. 1.5 daily Re

At the peak of Mount Arthur, using a sling psychrometer, you measure a wet bulb temperature of -5.5℃, and a dry bulb temperature of -5℃. Calculate the relative humidity

Answer 1

Given

wet bulb temperature = -5.5℃,

dry bulb temperature = -5℃.

Relative humidity =( (ew - (N* (1+0.00115*Tw) *(Td - Tw))/ed ) * 100

N = 0.668745

ed = 6.112*e(17.502*Td)/240.97+Td) = 6.112*e(17.502*(-5))/240.97+(-5)) =6.4445

ew = 6.112*e(17.502*Tw)/240.97+Tw) = 6.112*e(17.502*(-5.5))/240.97+(-5.5)) = 6.4316

Relative humidity =( (ew - (N* (1+0.00115*Tw) *(Td - Tw))/ed ) * 100

                                   = ( (6.4316 - (0.668745* (1+0.00115*(-5.5)) *((-5) - (-5.5)))/6.445 ) * 100

                          = ( 6.4316 - 0.6325)/6.445)*100

                          = 88 %

Relative humidity = 88%

where e=2.7183