Climate drivers are a factor or process that influences the behaviour of the climate system, such as solar radiation and ocean currents.

Climate drivers are activated by changes in large-scale circulation patterns that are controlled by the relationships between sea surface temperatures and atmospheric circulation.

Global circulation patterns in the atmosphere and oceans act to transport heat from the equatorial area towards the poles. Generally, in areas of warm sea surface temperatures, there is moist, rising air that leads to convection and rainfall with low pressure at the surface. The opposite is true for areas of cold sea surface temperatures, which tend to have very little cloud cover or rainfall and areas of high pressure due to sinking cold air.

Air in the atmosphere flows from areas of high pressure to areas of low pressure. As such, a ‘circulation cell’ (image below) will form with air rising on one side of the cell (warm side) and descending on the other side of the cell (cool side), with air moving between the two sides.

Multiple circulation cells operate worldwide and at varying latitudes and are responsible for the world’s climate and climate variability.

Oceanic and atmospheric circulation patterns over the Pacific Ocean during ENSO neutral years (Credit: Bureau of Meteorology)

There are a number of climate drivers that affect Australia, such as the El Niño-Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), the Madden-Julian Oscillation (MJO), the Southern Annular Mode (SAM) and the Sub-tropical Ridge (STR).

Each of these drivers operates at a different time scale, during different seasons, and impacts different regions.

These climate drivers become active due to changes in the location of unusually warm or cool sea surface temperatures, which leads to changes in the strength and location of the circulation cell described above.

Climate Drivers of Australia (Credit: Bureau of Meteorology)

This package will go into detail about these climate drivers and more. A fantastic resource has been created depicting the cliamte drivers as Climatedogs and liken their behaviour and patterns to working dogs. It is important to remember that climate drivers (and climatedogs) work together to impact the climate, so we need to look at the combined effect of all the indicators to get a clear idea of what to expect in the future.