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N CLIMATOLOGY 



Figure 4.22. Diurnal, seasojial, and vertical variation ofNofor Portland, Me. (PWM). 



maritime air that keeps the mean temperatures both low and uniform. 

 By comparison, the continental stations show relatively large diurnal and 

 seasonal ranges controlled in large measure by the radiative heating and 

 cooling, summer to winter and day to night. The east-coast stations 

 display a general increase of iVo from north to south arising from the 



