Three cities have the following temperature (T) and dew point (Td ) during a July afternoo...

Three cities have the following temperature (T) and dew point (Td ) during a July afternoon:

Atlanta, Georgia, T 5 90°F; Td 5 75°F

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Baltimore, Maryland, T 5 80°F; Td5 70°F

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Norman, Oklahoma, T 5 70°F; Td 5 65°F

(a) Which city appears to have the highest relative humidity?

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(b) Which city appears to have the lowest relative humidity?

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(c) Which city has the most water vapor in the air?

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(d) Which city has the least water vapor in the air?

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(e) For each city use Table on p. 107 and the information on the same page to calculate the relative humidity for each city.

Table Saturation Vapor Pressure over Water for Various Air Temperatures*

AIR TEMPERATURE		SATURATION VAPOR PRESSURE	AIR TEMPERATURE		SATURATION VAPOR PRESSURE
(°C)	(°F)	(MB)	(°C)	(°F)	(MB)
–18	(0)	1.5	18	(65)	21.0
–15	(5)	1.9	21	(70)	25.0
–12	(10)	2.4	24	(75)	29.6
–9	(15)	3.0	27	(80)	35.0
–7	(20)	3.7	29	(85)	41.0
–4	(25)	4.6	32	(90)	48.1
–1	(30)	5.6	35	(95)	56.2
2	(35)	6.9	38	(100)	65.6
4	(40)	8.4	41	(105)	76.2
7	(45)	10.2	43	(110)	87.8
10	(50)	12.3	46	(115)	101.4
13	(55)	14.8	49	(120)	116.8
16	(60)	17.7	52	(125)	134.2

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(f) Using both the relative humidity calculated in (e) and the air temperature, determine the heat index for each city using Fig. (p. 108).

FIGURE Air temperature (°F) and relative humidity are combined to determine an apparent temperature or heat index (HI). An air temperature of 96°F with a relative humidity of 55 percent produces an apparent temperature (HI) of 112°F.