Cloud clustering patterns reveal increasing severity of extreme rainfall in tropics

By studying cloud clustering patterns in a warming climate, scientists have shown that with rising temperatures, extreme rainfall events become more severe.

Focussing on the area of the tropics around the equator, the scientists from the Institute of Science and Technology Austria (ISTA) and the Max-Planck-Institute for Meteorology (MPI-M) in Germany used a climate model to study how cloud and storm clustering impacted extreme rainfall events.

They found that with warming climate, extreme rainfall events in the tropics increase in severity more than what was expected from the theory.

“We can see that when clouds are more clustered, it rains for a longer time, so the total amount of rainfall increases,” said Jiawei Bao from ISTA, and the lead author of the study published in the journal ‘Science Advances’.

“We also found that more extreme rain over high-precipitation areas happens at the cost of expansion of dry areas – a further shift to extreme weather patterns. This is due to how clouds and storms cluster together, which we could now simulate with this new climate model,” said Bao.

Their model captures the complex dynamics of air movement and hence, simulates the climate with a much higher resolution than the previous ones that do not factor clouds and storms in as much detail, the researchers said.

These complex dynamics at play are involved in creating clouds and helping them congregate to form more intense storms, they explained.

Climate models divide the earth’s atmosphere into three-dimensional chunks, each with its own data about temperature, pressure, humidity, and many more physical properties.

Physical equations are then employed to simulate how these chunks interact and change over time to create a representation of the real world. Simplifications are introduced in these models to conserve on computing power and storage, the researchers explained.

“We used a climate model developed at MPI-M and analysed the data hosted at the German Climate Computing Centre in Hamburg with a resolution of just five kilometres which was very computationally expensive,” said Bao.

“All climate research is an immense collaborative effort by hundreds of people who want to contribute to our understanding of the world and our impact on it,” added Bao.