NASA launched its Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission in 2006 to study the impact of clouds in the atmosphere. The climate satellite uses lidar, which shoots laser light pulses at Earth’s surface and measures how they bounce back to measure the distance to objects below. The space agency’s goal is to combine that information with data from other satellites to show vertical structures, water content in clouds, and other climate indicators.
![Global distributions of surface particulate particulate organic carbon from CALIPSO lidar measurements Credit: Supplementary Materials, Behrenfeld et al. [2013]](https://eos.org/wp-content/uploads/2015/05/Lu-Figure_mk_embed_Web.jpg?3dabfe)
Lu et al. wanted to estimate exactly how much subsurface backscatter they could pick up from the spacecraft’s lidar measurements to more precisely determine its usefulness.
First, the team had to remove the signals they did not need from the lidar observations. Once that was accomplished, the backscatter signal showed significant correlations with chlorophyll a concentrations, an indicator of phytoplankton presence. They also found the signal was sufficient to estimate particulate organic carbon, a combination of living and dead organic material. The researchers say the two measurements taken together would allow scientists to calculate the ocean’s global carbon stock. (Journal of Geophysical Research: Oceans, doi:10.1002/2014JC009970, 2014)
—Eric Betz, Freelance writer
Citation: Betz, E. (2015), Hacking a climate satellite to see beneath the ocean’s surface, Eos, 96, doi:10.1029/2015EO030183. Published on 27 May 2015.
