Living on the coast of Belize I am normally surrounded by the most crisp, fresh air you can find anywhere in the tropics. The Northeast Tradewinds, which blow 80% of the year, caress 2000 miles of the Atlantic Ocean before encountering the tiny Caribbean Windward Islands, and then unimpeded, another 2000 miles across the clear, warm Caribbean Sea to Belize. From my front porch the air is often so clear I can discern individual trees on offshore islands 12 miles out to sea.
That is why I took a keen interest in an unusually large dust cloud that left Africa in mid-June of 2020. Dust plumes, known as the Saharan Air Layer, commonly form on the west coast of the African continent every three to five days from late spring through early fall and move into the tropical Atlantic Ocean. Most dissipate with a few weeks, but this one was different. I keenly watched this large plume, easily visible by satellite, as it headed across the Atlantic and entered the Caribbean Sea a week later.
The morning of the plume’s arrival, low clouds hid the sun and an umber haze rolled in like a slowly breaking wave. The sky and sea turned a light russet shade, and an evening light blanketed Belize for hours.
The darkness and gloom belied the significance of the Saharan dust cloud. This mineral laden plume deposits much needed nutrients that foster the health of our rainforests and feed aquatic life over much of the Northern Atlantic Ocean.
The dust cloud also weakens tropical cyclones or tropical disturbances due to its extreme dryness. Since dusty air has about 50% less moisture than the typical moisture laden Tradewinds, it promotes downdrafts around storms that weaken them, potentially suppressing dangerous hurricanes.
I spent the day with my finger on the shutter release, watching and photographing the effects of the dust cloud as a copper light waxed and waned. By the following morning, the Northeast Tradewinds had swept the dust away. I could again see trees on the islands far at sea. The normal clear, fresh air had returned.