HOUSTON – Its that time of year again. Meteorological Summer began on Sunday.
Not only is it the start of hurricane season, it is also start of the time of year when the skies can turn hazy as dust from Africa’s Sahara Desert makes its way across the Atlantic Ocean and into the Gulf.
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The National Weather Service is currently monitoring a plume of Saharan dust headed towards the Gulf and Southeast Texas. It is expected to reach the area during the back half of the week.
But why does this happen and what all does it do?
Explaining Saharan dust
While the name is self-explanatory, the phenomenon seen in this part of the country in the summer begins with dust particles that originate from the Sahara Desert in Africa. These particles are made up of tiny specks of minerals, such as sand and soil.
- RELATED: Pros and cons of Saharan dust
The Saharan Air Layer (SAL) is the layer of warm, dry, and dusty air that forms during the summer months. It extends vertically from the surface up to about three miles into the atmosphere and can travel thousands of miles.
It impacts weather patterns, air quality, and even hurricane development.
What does it do?
The upside:
Limits tropical development: Hurricanes need moist, unstable air to form, similar to a thunderstorm. The Saharan Air Layer is dry and stable which inhibits the development or intensification of tropical storms.
Saharan dust creates a very dry atmosphere that is not conductive for thunderstorms.
If the layer of Saharan dust is thick enough it can also reflect some sunlight which lowers the water temperature.
Sunrises and sunsets: When sunlight passes through the Earth’s atmosphere, it interacts with particles present in the air, such as dust, water droplets, and gases. The dust particles scatters sunlight, leading to move vibrant sunrises and sunsets, especially for red, orange, and pink hues (longer-wavelength colors).
It is the same phenomenon to why smoky skies bring more vibrant colors at dusk and dawn.
Helps our marine ecosystem: As the Saharan Dust travels over the Atlantic Ocean some of the particles will be dropped on the surface of the ocean, including mineral nutrients, such as iron and phosphorus. These nutrients act as fertilizers, promoting the growth of phytoplankton at the surface.
Phytoplankton are tiny, plant-like organisms that are at the the base of the marine food chain. More phytoplankton brings more food for all marine life starting from zooplankton to small fish, and eventually larger fish and whales.
The downside:
Poor air quality: Saharan dust contains fine particles, known as particulate matter (PM), which can be inhaled into the respiratory system. These particles can be small enough to penetrate deep into the lungs, leading to respiratory issues, especially for individuals with pre-existing respiratory conditions like asthma or bronchitis.
When inhaled the particles can cause irritation and inflammation in the respiratory system. This is why our air quality plummets with the dust.
Reduced visibility: Saharan dust can reduce visibility by creating a hazy or foggy appearance in the air.
This can be problematic for transportation like airplanes as impairing visibility increases the risk of accidents.