Dust Observations and Climatology - Mineral Dust: A Key Player in the Earth System - page 166

Fig. 7.9 An example demonstrating the capability of CALIOP to track dust long-range transport
during a dust event that originated in the Sahara desert on 17 August 2007 and was transported to
the Gulf of Mexico. Vertical images are 532-nm attenuated backscatter coefficients measured by
CALIOP when passing over the dust transport track (From Liu et al. 2008a )
as dust (Omar et al. 2009 ). CALIOP started in spring 2006 measuring aerosol
profiles with a 30-m vertical resolution and 70-m horizontal resolution. CALIPSO
has acquired the largest amount of global dust vertical profiles so far (Mona et al.
2012 ,Fig. 7.9 ). The validation studies performed using ground-based lidar stations
as a reference have shown a good quality of the CALIOP dataset (Pappalardo
et al. 2010 ). Based on CALIOP measurements, a number of dust studies have
been performed recently, especially for the characterization of North African dust
transport over the Atlantic (Liu et al. 2008a ; Ben-Ami et al. 2009 ; Generoso et al.
2008 ) and analysis of 3D structure of Asian dust (Huang et al. 2007 ; Uno et al.
2008 ). In parallel, Peyridieu et al. ( 2010 ) have shown the ability of infrared sounders
like AIRS to retrieve the dust layer mean altitude quite accurately by comparing
their results with the CALIOP-altitude product over the Atlantic. Figure 7.10 shows
an illustration of a monthly climatology of dust mean altitude derived from AIRS
data. This climatology allows observations of the spatial and seasonal variations of
mean altitude of dust transport over the Atlantic, characterized by maximum heights
in summer months and minimum heights in winter.
The CALIPSO mission offers considerable improvement in determining the
vertical distribution of dust properties, also in situations where passive sensors do