Observational constraints on atmospheric and oceanic cross-equatorial heat transports: revisiting the precipitation asymmetry problem in climate models

What is it about?

There is currently more sunlight energy absorbed by Earth than is emitted as infrared energy to space, causing the planet to heat up. We find this energy “imbalance” is mostly observed south of the equator (southern hemisphere). Our calculations show that ocean currents move a large proportion of this extra energy across the equator to the seas in the northern hemisphere while atmospheric winds move a smaller fraction of energy back south across the equator. Importantly, we discovered that simulations showing an unrealistic northward flow of energy by winds blowing across the equator also have rainfall patterns that do not match our observations.

Featured Image

Why is it important?

Human-caused greenhouse gas emissions are warming Earth’s climate. Using simulations to predict how rainfall patterns will change as the climate warms is vital for making decisions on how best to adapt to and mitigate (or reduce) climate change. Simulations of Earth’s climate tend to produce too much rainfall south of the equator compared to rainfall north of the equator. Our findings suggest that by improving simulated energy flows across the equator we will be able to predict rainfall patterns more accurately.