October 23, 2019 - Dust off Northwestern Australia

Strong winds carried dust across parts of Western Australia and over the Pacific Ocean on October 21, 2019. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Aqua satellite acquired a true-color image of the scene as it passed overhead on that same day.

Broad plumes of red dust rise from the Kimberly region of Western Australia. Located at the northern tip of the region, October in the Kimberly falls in the transitional time between the dry season (May through September) and the wet season (November to April). During the dry season, clear skies and calm winds are the norm while the wet season brings hot, humid, unsettled weather with frequent storms. October weather sometimes picks and chooses between the two, with clear weather giving way—sometimes suddenly—to windy, stormy weather. This makes October an excellent time for dust storms.

In the far west (left) of the image, dust coalesces where parallel arcs in the clouds and dust mark an atmospheric wave. Waves can form in the atmosphere for a variety of reasons. Sometimes the movement of an air mass over a bumpy feature—a mountain ridge, a volcano, or an island amidst a flat sea—will force air to rise or sink, creating ripples in the sky like those propagating across the surface of a pond. Other times, the collision of different air masses will cause a rippling effect. In this case, the waves are likely the result of strong off-shore winds interacting with breezes blowing in different directions over the Indian Ocean.

Image Facts
Satellite: Aqua
Date Acquired: 10/21/2019
Resolutions: 1km (969.5 KB), 500m (2.7 MB), 250m (2 MB)
Bands Used: 1,4,3
Image Credit: MODIS Land Rapid Response Team, NASA GSFC