Moisture

states of water: related to energy and motion, solid, liquid, vapor, melting, evaporation, sublimation, freezing, condensation, deposition;

absolutehumidity - mass of water in a given volume of air (g/kg); vapor content of air

relative humidity - "fullness" of the air, capacity is temperature dependent (as T increases, capacity increases), measured in percent

                        amount of vapor      x 100

                        max. capacity

dew point- temperature where RH = 100%  air reaches saturation and condensation overwhelms evaporation, measures the amount of moisture in the air

fog:  air cooled by cold surface, radiation fog, advection fog (San Francisco type)

clouds: adiabatic cooling, as air rises, it expands and temperature decreases, relative humidity increases, if RH=100% condensation occurs and clouds form

Causes of uplift-  convectional (thermal uplift, warm air rises),  orographic lifting ,  frontal lifting,  convergence

classification of clouds:  cirrus,  stratus, cumulus,  lenticular, fog

Precipitation:  rain, snow, sleet, hail, freezing rain (glaze)

 


Describe the three states of H2O and the processes that connect them. 

Explain relative humidity.  How is it calculated?  What is its relationship to dew point?  Explain how relative humidity can be raised or lowered. 

Be able to interpret the graph of water vapor content vs. temperature. (homework)  Be able to determine the vapor capacity of air at a given temperature, to calculate the relative humidity given temperature and vapor content, to determine the dew point if given vapor content, and to use dew point to determine vapor content.

What is fog?  Describe two ways in which it forms.  What role does wind play in each?

Describe how uplift and adiabatic cooling causes clouds to form.  Describe the main types of clouds.

Describe the main ways of causing the initial uplift of air masses.  What type of clouds are associated with surface heating and convection?  What type of clouds are associated with orographic lifting? 

Compare and contrast the types of precipitation:  rain, snow, sleet, freezing rain, hail.  Which requires a strong updraft in order to form? 

Be able to identify clouds from photographs.



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