Assignment 11 



Meteorological Elements; Fundamental Oceanography 



Text: Pages 357 - 380 



Learning Objective: Relate air 

 mass saturation, temperature, 

 and dewpoint to fog formation, 

 and identify composition and 

 types of fog and conditions 

 applicable to the formation of 

 each type. 



11-1. Assume that two masses of air contain the 

 same percentage of water vapor and that 

 both are at the same pressure. Mass A is 

 at a higher temperature than mass B. The 

 temperature of each mass is lowered by 

 the same amount and mass A reaches its 

 dewpoint due to the temperature drop. 

 How does this drop in temperature affect 

 mass B? 



1. Mass B is cooled below its dewpoint 

 and some of its water vapor condenses 



2. Mass B approaches saturation but no 

 water vapor condenses 



3. Mass B is not cooled below its dew- 

 point, hence no water vapor condenses 



4. All the water vapor in mass B 

 condenses 



11-2. Assume that two masses of air are at the 

 same temperature and pressure, but that 

 mass A is more nearly saturated with 

 water vapor than mass B. What may be 

 concluded about the dewpoints of the two 

 masses? 



1. The dewpoint of mass B is higher than 

 that of mass A 



2. The dewpoint of mass A is higher than 

 that of mass B 



3. The dewpoints of masses A and B are 

 the same 



4. The dewpoints of masses A and B are 

 different, but not enough information 

 is given to determine which is higher 



11-4. Which of the following types of fog forms 

 only over land during nighttime? 



1. Advection fog 



2. Radiation fog 



3. Land advection fog 



4. Steam fog 



11-5. Radiation fog is common in areas charac- 

 terized by 



1. high pressure, low wind speed, and 

 clear skies 



2. low pressure, low wind speed, and 

 cloudy skies 



3. high pressure, high wind speed, and 

 cloudy skies 



4. low pressure, high wind speed, and 

 clear skies 



11-6. Fog that is produced when warm air is 

 transported over a cooler surface is 

 called 



1. upslope fog 



2. frontal fog 



3. advection fog 



4. radiation fog 



11-7. Sea fog is formed when the wind brings 



1. dry warm air over a colder ocean 



2. moist warm air over a colder ocean 



3. moist cool air over a warmer ocean 



4. dry cool air over a warmer ocean 



11-8. Land advection fog may be caused by any 

 of the following conditions EXCEPT 



1. warm air being forced up a slope by 

 the wind 



2. an onshore breeze bringing maritime 

 air over a land surface which has 

 cooled off by radiation at night 



3. fog being formed over the ocean and 

 blown over the land during either 

 day or night 



4. air flowing from warm, bare ground to 

 snow-covered ground nearby 



11-3. Which of the following will result in the 

 saturation of an air mass? 



1. Rising dewpoint 



2. Lowering humidity 



3. Lowering dewpoint 



4. Rising temperature 



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