Relation Between the Movement of the Sub-Tropical and Polar Fronts and the Stall (Hiatus) in the Global Earth Surface Temperature.

Abstract:

An examination of the poleward movement of the Sub-tropical and the Polar upper troposphere fronts shows a similar stall (hiatus) as is seen in the global mean surface temperature of the Earth. The global mean surface temperature of the Earth is the areal average of the temperatures in the Hadley, Ferrell, and Polar convective cells, which are separated by the Sub-tropical and Polar fronts. As the two fronts move poleward, i.e. as the Hadley cell expands, more of the higher temperatures found in the Hadley cell are included in the global average and the mean global temperature increases. We have preformed a study of the possible causes of the movement of the fronts that might lead to such a hiatus. We find that there are two long-term causes that contribute most of the movement, both related to the heating and cooling of the lower tropical stratosphere: (1) radiative heating by the greenhouse gases, and (2) radiative cooling by molecular ozone. Between 1979 and 1998 the concentration of the greenhouse gases in the lower tropical stratosphere increased, while the concentration of molecular ozone decreased as a result of the release of Chlorofluorocarbons into the atmosphere. This will lead to a net increase in the temperature in the lower tropical stratosphere and in a net poleward movement of the fronts. However, between 1999 and 2013., although the additional greenhouse gases still lead to an increase in the temperature, ozone in the lower tropical stratosphere has also increased due to the implementation of the Montreal protocol, leading to a decrease in the temperature. In essence the observed stall (hiatus) in the mean global surface temperature can be explained as the result of a cancellation of the effects of the greenhouse gases and ozone on the temperature in the lower tropical stratosphere and hence on the poleward movement of the fronts.