The global atmospheric circulation on moist isentropes

Area of Science:

• Atmospheric Science
• Climate Dynamics
• Meteorology

Background:

• Global atmospheric circulation redistributes energy from the equator to higher latitudes.
• This circulation involves poleward transport of high-energy air and equatorward transport of lower-energy air.
• The turbulent nature of atmospheric circulation necessitates averaging for description.

Purpose of the Study:

• To investigate the impact of averaging methods on quantifying global atmospheric mass transport.
• To compare mass transport when averaged on moist isentropes versus dry isentropes.

Main Methods:

• Analysis of atmospheric mass transport using global circulation data.
• Comparison of transport calculations based on moist isentropic surfaces and dry isentropic surfaces.

Main Results:

• Total atmospheric mass transport is found to be twice as large when averaged on moist isentropes compared to dry isentropes.
• The enhanced transport on moist isentropes is attributed to a poleward flow of warm, moist surface air.
• This moist air rises in mid-latitudes, contributing significantly to the upper troposphere air mass in polar regions (up to 50%).

Conclusions:

• Averaging atmospheric circulation on moist isentropes provides a more comprehensive measure of mass transport.
• Water vapor plays a critical role in the poleward energy and mass transport within the global atmospheric circulation.
• The findings have implications for understanding climate dynamics and energy balance in the Earth's atmosphere.