124 Bujelow — The Inversion of Temperature Amplitudes 



Imagine the quaclrant of the earth's atmosphere between the 

 eqnator and tlic jioles to be rolled ont into straii>'ht lines, and 

 to extend from the surface to 1(),000 meters in altitude. Then, 

 the annual mean isotherms are disposed as indicated, subject 

 to modification in details owing to the present lack of data, 

 especially in the Tropics and the polar zones. The following- 

 facts should be noted: (1) In the lower levels the maximum 

 temperature is at a higher altitude in latitude 30° to 40° than 

 to the north or south of it ; (2) the general depression of 

 temperatures in the Tropics is due to the ascending circulation 

 and adiabatic cooling ; (3) the circulation in the Tropics is 

 westward, because the isotherms rise upwards in going north 

 and parallel to the earth's axis ; (4) the circulation in the 

 temperate zone is eastward for the opposite reason (see 

 paper, Monthly Weather lieview, January, 1904) ; (5) the 

 rate of circulation depends upon the density of the isotherms 

 in a line parallel to the earth's axis ; (6) it is a maximum west- 

 ward at the elevation 3000 to 4000 meters in the Ti'opics 

 decreasing downwards and upwards, and reversing to eastward 

 at about l0,000 meters (M. W. Review, April,. ' 1904) ; (7) it 

 increases upwards in the eastward drift of the temperate zones 

 to about 12,000 meters and then falls o£E, as first shown in the 

 International Cloud Report, 1898 ; (8) the chief function of the 

 westward drift in the Tropics is to counteract by its motion the 

 adiabatic cooling of the ascending air ; (9) the chief function of 

 the eastward drift is by its motion to hold the heated air of the 

 tropic zone away from the polar region ; (10) the small polar 

 overflow in the upper levels is restricted to latitudes 50° or 60° 

 by this circulation ; (11) there is no pronoiuiced upper pole- 

 ward current and no well-defined lower equatorward current, 

 ■with a neutral plane separating them, as Ferrel assumed in his 

 canal theory ; (12) the leakage currents from the Tropics to 

 the temperate zones may occur in all levels, and then the cen- 

 tei's of action and the wandering cyclones and anticyclones are 

 formed; (13) the momenta of motion are continuously being 

 readjusted between temperature and circulation to keep their 

 sum a constant, and the angular rotation of the earth on its 

 axis a constant ; (14) in case the solar energy raises the tem- 

 perature of the Tropics, with its westward drift, it follows that 

 in the temperate zones there is an increase of eastward drift, a 

 downflow of air, an increase of cold areas, and a decrease of 

 amplitudes and the leakage currents; (15) an inversion of 

 temperature in the temperate zone is a necessary result of this 

 circulation, to balance an increase of tempei'ature in the 

 Tropics from the solar radiation energy. This, then, accounts 

 for the many discrepancies which have l)een announced by 

 investigators when comparing station records directly with the 



