"Haboobs/Dust storms/Sand storms" - If you were to listen to these phrases, What would immediately strike your imagination? - MIP3 and Tom Cruise being chased by a towering wall of dust? Remote martian deserts with twirling dust devils? Climax from most of the sci-fi 'end of the world' movies? In a time where we proclaim about global warming, drought periods and climate change, it might not be wildly imaginative to say that they we no more need a movie to show such extreme behemoth events, we have them all happening right in our pale blue dot! Well, that's exciting! Oops! Dangerous! well, this is how I typically reacted when I initially heard about the July 5,2011 haboob in one of my graduate classes.
"A hundred year event - A mile high , 100 mile wide dust storm roared through Phoenix bringing the visibility levels to zero", quoted a reputed news report. People of Phoenix freaked out saying they have never seen such a massive dust event in their lifetime. That was the giant Phoenix "HABOOB" (July 5,2011) and this is what my research delves into.
HABOOBS
We all know about dust storms and the fact that dust particles lofted during these events are harmful to human health. But,why would there be coined a sophisticated term to describe them and why should we talk care when we have ample science questions in the queue? I had similar questions too.
The answer would become apparent if you sneak a peek in to this video http://www.youtube.com/watch?v=8vQMuwRjI6s. This was the tumbling giant Phoenix haboob (July 5, 2011).
WHAT ARE WE INDEED WITNESSING DURING A HABOOB?
If you were to picture blowing dust from all directions and a beautiful dust cloud , probably you are getting only half of the story. I hear your question - why, when and how does this start if this is not a quotidian blowing dust event?
Haboob is a common term in Africa and middle east Asia during the summer time monsoon . But this was less common in US, until the day when NWS folks, weather agencies and NASA itself turned their eyes to look at something so massive overtaking the western United States. The story begins on a hot summer day when a line of thunderstorms form over a region. When the meteorological conditions are right, they collapse creating what is called as a 'downburst' (cold parcel of precipitation outflowing from the thunderstorms and reaching the surface).
Such down bursts create strong winds and the thunderstorm outflow or the cooler air mass that reached the surface moves towards the region of lower elevation. As they progress, they pick up everything in their way and act as a self fueling engine. They trigger storms , cause air to rise up and descend and thereby creating a line of thunderstorms.
Haboobs = thunderstorm+downburst+strong winds + dust - so, this is indeed complex !
STORY OF PHOENIX
Unfortunately, Phoenix happens to be a valley at the lowest elevation when compared to its neighboring areas. So, the outflows from Tucson thunderstorms and those from the north typically move towards Phoenix. Also, the potential dust source regions extending from Tucson to Phoenix fuel the event. As it approaches Phoenix, dust walls from several pathways (typically, from north west of Phoenix, from Yuma and from Tucson) converge leading to such an incredible amount of moving dust. Dust storms occurring from these meteorological processes are called 'haboobs'.
It is highly rapid and spontaneous. Hence, this appears as a challenge for forecasters. My research uses a weather/chemistry model, satellite observations and ground truth to predict such massive dust storms and analyse the fate of dust from the haboobs.
If you are interested to learn more about my research and modeling and prediction of such massive dust storms , please stop by the abstracts and talks posted in my website : https://sites.google.com/site/spaceaish/graduate-conferences/agu-2012
