at California State University, Chico
Background
An article in the
Summer 2004 UCAR Quarterly describes how REAL got started. A description of conditions at NCAR resulting in the closure of the REAL program there can be found in an August 2008 article in Science by Eli Kintisch.
The Fall 2009 issue of Inside Chico State describes how REAL came to Chico State.
How does it work?
Four refereed journal articles and two US patents
( 7583364 and
7580127 )
describe the key aspects of the REAL. Briefly, it uses very short pulses of invisible, eye-safe, near-infrared
electromagnetic radiation in much the same way as weather radars use pulses of microwave radiation. The wavelength of near-infrared radiation, approximately 10,000 times shorter than microwaves, makes the lidar sensitive to suspended particulate matter (aerosol particles: dust, smoke, pollen, and haze particles). Just as radars can tell meteorologists where it is raining and snowing, the lidar can be used to locate clouds of particulate matter. In fact, because the lower atmosphere is usually rich with aerosol from both natural and man-made sources, the lidar almost always detects signal from "background aerosol". By sensing variations and movement in the background aerosol, the REAL is capable of revealing atmospheric circulations and phenemona that are difficult to observe using traditional methods. The key strength of REAL is the power of the images and animations to show spatial structure and evolution of "clear" atmospheric flow.
Why?
One popular approach to conducting atmospheric research is by
simulating atmospheric phenemona in a computer. The REAL can be used to provide observations to test atmospheric models. This is how we build confidence that a model is accurate and providing the right answers. One example of how elastic backscatter lidar data can be used to test a model can be found in
Mayor et al. 2003. Other examples can be found in
Sullivan et al. 1998 and
Doyle et al. 2009. In the future, we will create algorithms and software to extract quantities from the REAL data to make atmospheric model validation easier.
In addition to observing atmospheric structure and dynamics via the "background aerosol", the lidar can also be used to observe the transport and dispersion of particulate matter near the sources. For example, emissions from industrial stacks and mining operations. The lidar can be used to provide direct, precise, real-time location and heading of aerosol plumes. This information can be used to test disperson models and even warn the populations downstream of release sites as well as take low-regret protection actions such as shutting ventillation intakes.
Where?
The REAL is currently located in
Chico, California. It has been deployed at the following locations: Washington D.C. (May 2004); Dugway UT (Oct. 2004, June 2005); Albuquerque NM (Sept. 2005); Independence CA (March 2006), and Dixon CA (March 2007). The REAL can be transported to anywhere accessable by tractor-trailer. It requires a clear line-of-sight to operate.
Future work:
Many excellent research opportunities exist to apply the REAL in atmospheric science as well as make it more useful, easier to use, and less expensive. The immediate top priority is to develop algorithms and software to automatically extract quantities from the images such as vector flow fields, boundary layer height, and the location of features such as micro-fronts and aerosol plumes. Projects are available for students of almost all majors and educational levels.
For more information, please contact
Dr. Shane D. Mayor.