Monsoon Rains Have Become More Intense in the Southwest in Recent Decades

Typography

Monsoon rain storms have become more intense in the southwestern United States in recent decades, according to a study recently published by Agricultural Research Service scientists.

Monsoon rain storms have become more intense in the southwestern United States in recent decades, according to a study recently published by Agricultural Research Service scientists.

Monsoon rains—highly localized bursts of rain—have become stronger since the 1970s, meaning the same amount of rain falls in a shorter amount of time—by 6 to 11 percent. In addition, the number of rainfall events per year increased on average 15 percent during the 1961-2017 period.

Monsoon rain events are usually the result of strong convection or upwelling air currents due to the difference in temperature between the earth's hot surface and the cooler atmosphere. It is characterized by intense downpours that fall in less than 1 hour.

"We attribute these monsoon rain increases to climate change in the southwest, which the General Circulation Models (GCMs) predicted would happen if the atmosphere gets warmer. What is unique about our study is that we have validated the GCM simulations with observed rainfall data," explained hydrologist/meteorologist Eleonora M. C. Demaria with the ARS Southwest Watershed Research Center in Tucson, Arizona, who co-led the study.

Read more at US Department of Agriculture - Agricultural Research Service

Image: Individual, isolated monsoon rainstorms have gotten more intense and are happening more often in the Southwest US, according to an ARS study. (Credit: ARS-USDA)