NASA's CATS Eyes Clouds, Smoke And Dust From The Space Station

Image Caption: The interactions between clouds and aerosols are illustrated in this image, taken by retired astronaut Chris Hadfield onboard the International Space Station. It shows contrails produced by aircraft (bright streaks) over the ocean. Credit: NASA/Chris Hadfield

Provided by Heather Hanson and Kate Ramsayer, NASAs Goddard Space Flight Center

Turn on any local TV weather forecast and you can get a map of where skies are blue or cloudy. But for scientists trying to figure out how clouds affect the Earths environment, whats happening inside that shifting cloud cover is critical and hard to see.

To investigate the layers and composition of clouds and tiny airborne particles like dust, smoke and other atmospheric aerosols, , scientists at NASAs Goddard Space Flight Center in Greenbelt, Maryland have developed an instrument called the Cloud-Aerosol Transport System, or CATS. The instrument, which launches to the International Space Station in December 2014, will explore new technologies that could also be used in future satellite missions.

From space, streaks of white clouds can be seen moving across Earths surface. Other tiny solid and liquid particles called aerosols are also being transported around the atmosphere, but these are largely invisible to our eyes. Aerosols are both natural and man-made, and include windblown desert dust, sea salt, smoke from fires, sulfurous particles from volcanic eruptions, and particles from fossil fuel combustion.

Currently, scientists get a broad picture of clouds and air quality conditions in the atmosphere and generate air quality forecasts by combining satellite, aircraft, and ground-based data with sophisticated computer models. However, most datasets do not provide information about the layered structure of clouds and aerosols.

CATS will provide data about aerosols at different levels of the atmosphere. The data are expected to improve scientists ability to track different cloud and aerosol types throughout the atmosphere. These datasets will be used to improve strategic and hazard-warning capabilities of events in near real-time, such as tracking plumes from dust storms, volcanic eruptions, and wildfires. The information could also feed into climate models to help understand the effects of clouds and aerosols on Earths energy balance.

Clouds and aerosols reflect and absorb energy from the sun in a complex way. For example, when the suns energy reaches the top of the atmosphere, clouds can reflect incoming sunlight, cooling Earths surface. However, clouds can also absorb heat emitted from Earth and re-radiate it back down, warming the surface. The amount of warming or cooling is heavily dependent on the height, thickness, and structure of clouds in the atmosphere above.

Clouds are one of the largest uncertainties in predicting climate change, said Matt McGill, principal investigator and payload developer for CATS at Goddard. For scientists to create more accurate models of Earths current and future climate, theyll have to include more accurate representations of clouds.

Thats where a new instrument like CATS comes in. CATS is a lidar similar to a radar, but instead of sending out sound, lidars use light. CATS will send a laser pulse through the atmosphere towards a distant object like a cloud droplet or aerosol particle. Once the energy reaches the object, some of the energy is reflected back to the lidar receiver. Scientists can calculate the distance between the instrument and the object, based on the time it takes the energy to return to the receiver, thereby determining the altitudes of cloud and aerosol layers. The intensity of this return pulse also allows scientists to infer other properties, such as the composition of clouds, and the abundance and sizes of aerosols.

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NASA's CATS Eyes Clouds, Smoke And Dust From The Space Station