African Dust and Its Impact on African Dust and Its Impact on ClimateClimate

Xiaoyu Liu MPO

Outline Outline

What is african dust?What is african dust?

What is its physical property?What is its physical property?

How does it affect climate?How does it affect climate?

The future workThe future work

Who is who?Who is who?

Two conditions to product dust

The appropriate meteorological conditions to supply momentum to the surface.

The appropriate soil conditions to allow dust production.

Why it is so important?Why it is so important?

Look at its locationLook at its location

Its impact on climateIts impact on climate

Change the local climateChange the local climate

Global warmingGlobal warming

Change the strength of Change the strength of hurricanehurricane

Ruin the marine ecosystemRuin the marine ecosystem

Change of the local Change of the local climateclimate

Sahara Desert and Dusty Sahel Block "Normal" Movement of Monsoon and Winter Rains

Due to the maximum latitude of the Sun's position during seasonal changes, the maximum differential heating occurs closest to the equator. The bounded areas show where monsoonal flow occurs most often.

Global warmingGlobal warming

It is a significant source of climate warming for the dusty Sahelian airs do capture, store and transport solar heat that would otherwise be dissipated in normal rainfall.

Change of the strength Change of the strength of hurricaneof hurricane

Sahelian dusts and the supersaturated airs that flow over the Eastern Atlantic Ocean region in which most hurricanes are spawned, are a significant source of energy for the formation of hurricanes.

The hurricane "season" is also exactly the season of the Sahelian dust flow.

How is hurricane formedHow is hurricane formed

Hurricanes form where ocean waters are Hurricanes form where ocean waters are warmed to temperatures of greater than 77 warmed to temperatures of greater than 77 degrees Fahrenheit. The formation starts degrees Fahrenheit. The formation starts when micro-cyclonic air motion at the sea when micro-cyclonic air motion at the sea surface induced by rapid evaporation and surface induced by rapid evaporation and accelerated by wind induced turbulence at accelerated by wind induced turbulence at the water-air interface. The micro-cyclones the water-air interface. The micro-cyclones become a cyclonic storm when sufficient become a cyclonic storm when sufficient energy is injected into aggregating micro-energy is injected into aggregating micro-cyclonic systems. cyclonic systems.

The Sahelian air is a high energy source that flows into spawning zone at the time of hurricane formation.

This is because the Sahelian air is supersaturated with moisture.

Though the air is too hot for mineral dust particles to nucleate precipitable moisture, the ocean atmosphere and the micro-cyclonic systems are full of salt particles, which are efficient nucleators.

When the marine salt particles are lofted into the Sahelian air, nucleation does occur with release of large amounts of energy at all altitudes.

“Take a deep breath in Miami this summer and chances are you'll inhale a bit of Africa.”

Ruin the marine Ruin the marine ecosystemecosystem The degradation of Caribbean marine species

appears to be related to major El Niño events. Land sources of dust plumes in North Africa

(Western Sahara and Mauritania) provide more dust to the Atlantic easterly trade winds in major El Niño years .

The dust appears to affect coral and reef-dwelling animals. In Florida waters, Saharan dust brings in a critical nutrient, iron, leading to blooms of toxic algae.

Protect your lungsProtect your lungs

African dust particles contain large amounts of iron as a coating, providing its characteristic red-brown color. Once dust is deposited in the lung, the iron coating would probably be released to the lung tissue.

Long long way to go……Long long way to go……

we should work to remove dust from the Sahelian atmosphere. And there is a proven way to keep significant amounts of dust out of the Sahelian atmosphere. The revegetation of the Sahelian wastelands will suppress the dust. The appropriate proven methods are those used in the United States to cure the 1930s Dust Bowl. They are the methods used by the US Soil Conservation Service (SCS). Modification and use of those SCS methods has already been successful in the Sahel.

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