Dry layers in the tropical atmosphere observed by aircraft and their global behavior

What is it about?

This study details the structure and occurrence frequency of dry layers of air that have been observed between 5--15 km altitude in the tropical atmosphere (near Guam island). These layers are dry, and they are also rich in ozone, which suggests that they originate at higher altitudes where ozone content is larger (in the stratosphere, roughly above 17 km altitude). A global atmospheric model is then used to quantify the global behavior of these layers, as they indicate regions that are prone to stratosphere-troposphere exchanges, i.e., the mixing of air masses between two atmospheric reservoirs that have very different characteristics.

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Why is it important?

The presence of dry, ozone-rich (stratospheric) air in the troposphere indicates downward transport of stratospheric air into the troposphere, which may modulate the frequency and location of tropical convection, a crucial element in the global atmospheric circulation.