<P> The Bergeron classification is the most widely accepted form of air mass classification , though others have produced more refined versions of this scheme over different regions of the globe . Air mass classification involves three letters . The first letter describes its moisture properties , with c used for continental air masses ( dry ) and m for maritime air masses ( moist ) . The second letter describes the thermal characteristic of its source region : T for Tropical , P for Polar , A for arctic or Antarctic , M for monsoon , E for Equatorial , and S for superior air ( an adiabatically drying and warming air formed by significant downward motion in the atmosphere ) . For instance , an air mass originating over the desert southwest of the United States in summer may be designated `` cT '' . An air mass originating over northern Siberia in winter may be indicated as `` cA '' . </P>
<P> The Bergeron classification is the most widely accepted form of air mass classification , though others have produced more refined versions of this scheme over different regions of the globe . Air mass classification involves three letters . The first letter describes its moisture properties , with c used for continental air masses ( dry ) and m for maritime air masses ( moist ) . The second letter describes the thermal characteristic of its source region : T for Tropical , P for Polar , A for arctic or Antarctic , M for monsoon , E for Equatorial , and S for superior air ( an adiabatically drying and warming air formed by significant downward motion in the atmosphere ) . For instance , an air mass originating over the desert southwest of the United States in summer may be designated `` cT '' . An air mass originating over northern Siberia in winter may be indicated as `` cA '' . </P>
in naming air masses the letter c stands for -- -- -- --
in naming air masses the letter c stands for -- -- -- --
continental air masses ( dry )
continental air masses ( dry )