The Science of Doom

One Look at the Effect of Higher Resolution Models

In #15 we looked at one issue in modeling tropical cyclones (TCs). Current climate models have actual biases in their simulation of ocean temperature. When we run simulations with and without these errors there are large changes in the total energy of TCs.

In this article we’ll look at another issue – model resolution. Because TCs are fast and small scale, climate models at current resolution struggle to model them.

It’s a well known problem in climate modeling, and not at all a surprise to anyone who understands the basics of mathematical modeling.

This is another paper referenced by the 6th Assessment Report (AR6): “Impact of Model Resolution on Tropical Cyclone Simulation Using the HighResMIP–PRIMAVERA Multimodel Ensemble”, by Malcolm Roberts and co-authors from 2020.

The key science questions addressed in this study are the following:

1) Are there robust impacts of higher resolution on explicit tropical cyclone simulation across the multi- model ensemble using different tracking algorithms?

2) What are the possible processes responsible for any changes with resolution?

3) How many ensemble members are needed to assess the skill in the interannual variability of tropical cyclones?

In plain English:

• They review the results of a number of climate models each at their standard resolution and then at a higher resolution
• When they find a difference, what is the physics responsible? What’s missing from the lower resolution model that “kicks in” with the higher resolution model?
• How many runs of the same model with slightly different initial conditions are needed before we start to see the year to year variability that we see in reality?

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