SALEX mission
Irene 2005

SALEX project description

The NOAA/AOML/Hurricane Research Division (HRD) recently completed first ever missions of its Saharan Air Layer Experiment (SALEX) around Tropical Storm Irene. The goal of these missions was to use GPS dropwindsondes launched from NOAA's G-IV high altitude jet to sample dry, dusty Saharan air that was surrounding Irene. Two SALEX missions were conducted on August 7-8 and because of Irene's remote location in the central Atlantic, Barbados was used as the base of operations. Scientists aboard the flights sampled areas of Saharan air around the storm that were 30-50% drier than the typical tropical atmosphere and also recounted seeing vast amounts of Saharan dust in these areas. They also noted that these measurements of the Saharan Air Layer were taken some 2000-3000 miles west of where it originated over the Sahara Desert, confirming the extreme long lived nature of this phenomenon.

The Saharan Air Layer's dry air, strong winds, and vast amounts of suspended mineral dust have been shown to inhibit the development of tropical cyclones in the Atlantic. Scientists plan to conduct more SALEX missions this hurricane season and again during the 2006 season. The data that is collected will be used to further our understanding of how the Saharan Air Layer affects tropical cyclones and will also be fed into forecast models in hopes of improving intensity forecasts.

More information on the Saharan Air Layer can be found on HRD's Tropical Cyclone FAQ page.

Erica Rule
AOML Outreach Coordinator

Crew photo taken in Barbados following the completion of the first-ever G-IV SALEX mission (August 7, 2005). Crew members from left: Will Odell (LT), Gordon Kitson, Jeff Hagan (LCDR), Michele Finn (CDR), Dale Carpenter, David Brogan, Jason Dunion (Chief Scientist), Ray Tong, and Barry Damiano (Flight Director). Photo taken by Jack Parrish.

Photo from the NOAA G-IV jet (flying at 45,000 ft) showing dusty Saharan air on the west side of Tropical Storm Irene the afternoon of August 8th.