Long-term records reveal the impact of climate change on atmospheric circulation

How climate change affects thermodynamic signals such as atmospheric temperature is relatively well understood. However, its influence on atmospheric circulation is more complex. Because the atmosphere is noisy and chaotic, and thermodynamic changes can cause effects that make circulation changes difficult to decipher.

Models provide many robust predictions about changes in atmospheric circulation due to climate change, but testing these predictions has proven difficult. This situation is beginning to change as researchers accumulate long-term observational records of atmospheric circulation and develop new tools.

In AGU Advances, researchers review the known impacts of climate change on circulation, summarize our current understanding of its mechanisms, and point out gaps in knowledge and opportunities for future research. They usher in a “golden age” in the study of circulation dynamics that could resolve discrepancies between models and observations and improve our understanding of how climate change affects the Earth’s climate system. is predicted.

Signals of climate change affecting circulation that have already been detected include a poleward shift of the jet stream in the lower troposphere and a weakening of the jet stream and storm tracks in the Northern Hemisphere. The dynamics of some signals are understood and thought to be due to human activity.

For example, efforts to improve air quality have reduced aerosols over land. Because aerosols reflect sunlight, this reduction increases surface radiation and surface temperature, which has weakened the summer Eurasian jet over the past 40 years.

The exact mechanisms behind other signals, such as a shift in the edge of the Hadley cell representing the edge of the arid subtropics where deserts are primarily located, are still under debate. Several other signals have been proposed or modeled, but have not yet been observed.

In some cases, there are clear discrepancies between modeled predictions and observations. These show opposite trends, for example, in changes in sea surface temperature patterns in the tropical Pacific Ocean, leading to discrepancies in regional storm track trends. Another challenge lies in distinguishing climate change-related responses from noise.

These and other issues could soon be solved, the authors say, with better data and the use of new tools such as artificial intelligence that provide improved analytical capabilities. Studies that track signals across seasons or regions, or focus on extreme events, could be particularly useful, they write.

Such advances will help uncover the mechanisms behind complex circulation dynamics, improve how they are represented in climate models, deepen our understanding of global atmospheric patterns, and improve predictions of climate change. It may be helpful.

This article is republished courtesy of Eos, sponsored by the American Geophysical Union. Read the original story here.