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Know Your Earth 3.0: CALIPSO
CALIPSO banner with Mark Vaughan

About Mark Vaughan

Mark Vaughan is a mathematician at NASA's Langley Research Center in Hampton, Va. He uses math to improve the lidar, or pulsating laser, instrument measurements on NASA's CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) satellite, which collects information on the distribution and movement of clouds and particles, called aerosols, in Earth's atmosphere. CALIPSO's lidar instrument works by pulsing laser light through the atmosphere. The way the laser reflects off of things in the atmosphere tells scientists what's there, like clouds and particles.

Vaughan went to Ferguson High School in Newport News, Va., and after a few philosophy classes at the College of William and Mary in Williamsburg, Va., he took a different path and received his bachelor's degree in mathematics from Christopher Newport University in Newport News. Thirty years ago, Vaughan couldn't imagine being anywhere else but on a boat in the Florida Keys under a warm, cloudless sky. Today, he lives in Newport News and is still interested in warmer climates, but in a different way. He's now studying how clouds and aerosols in the atmosphere are affecting global climate change.

Right now, Vaughan's focus is on measuring thin, wispy cirrus clouds high in the sky. Cirrus clouds are theoretically difficult to study. The ice crystals making up the clouds come in a large range of shapes and sizes, which changes the way the light scatters back. Vaughan and his colleagues want to understand one area, like cirrus clouds, well enough to use it to calibrate the instruments on CALIPSO, confirming the accuracy of their measurements. Without math, there's no way they're going to solve the lidar equation. Having a good calibration target is an essential requirement for scientists to better understand what is going on in the atmosphere, improve their predictive capabilities and better understand the role that clouds and aerosols have in climate change.


CALIPSO satellite scan showing smoke from wildfires over Greenland
A CALIPSO satellite scan showing smoke from wildfires over Greenland.
Credit: NASA

The CALIPSO satellite mission is a joint mission between NASA and CNES, the French space agency that launched on April 28, 2006. CALIPSO uses an innovative lidar instrument to see small particles such as dust, smoke, pollution and thin clouds that are often invisible to radar and the human eye. The lidar sends a series of short light pulses down through the atmosphere, and a fraction of them return to the satellite. The strength of the returned signal reveals the characteristics of the cloud and aerosol layers below. The time required for the signal to travel down through the atmosphere and return to the satellite is used to construct a vertical map showing locations of clouds and aerosols.

CALIPSO vertical profile of June 3 wildfires in Arizona

CALIPSO data showing a large smoke plume from 2011 Arizona wildfires is overlaid on an image from NASA’s Terra satellite.
Credit: NASA
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In April 2013, CALIPSO will mark its seventh year of operation and since it has launched more than 700 publications have been published using CALIPSO data products. CALIPSO has made important measurements of wild fire smoke, which can pose significant health hazards, particularly to young children and the elderly. CALIPSO data have also been used to estimate that dust crossing the Pacific Ocean, which accounts for 88 percent, or 56 million tons, of the total particle import to North America every year.

Additional Links

› Know Your Earth 3.0
› CALIPSO Mission
› CALIPSO Data and Information
› NASA CALIPSO Mission Page
› CALIPSO Profile
› CALIPSO Data Availability Tool