The EarthCARE satellite sees wildfires in Los Angeles from space. It has a lidar called ATLID that quickly measures and maps thin clouds and fine particles. But what does this instrument actually observe and why is ATLID special?
ATLID Lidar in Practice
The ATLID lidar can detect fine particles (aerosols) like smoke from fires and map their vertical distribution in the atmosphere. This provides insight into how high the smoke plumes rise. Additionally, it measures how the smoke absorbs and reflects light, which helps determine how much sunlight the smoke blocks or scatters.
During the wildfires in Los Angeles, multiple hotspots exist in the sprawling American city. The combination of local drought and strong Santa Ana winds intensifies the fires while blowing smoke towards the ocean before it can rise higher.
EarthCARE Above the Wildfires
The EarthCARE satellite flew over Los Angeles on January 11 at around 2:00 AM. Over the ocean, a portion of the smoke was lifted up to 2 kilometers. The combined ATLID measurements allow us to distinguish between different types of fine particles, such as soot, organic material, and dust. The layer of fine particles, up to 2 kilometers high, consists of smoke, while the aerosol layer to the south contains more sea salt and smoke. Over land north of Los Angeles, it is a mix of sea salt and local emissions.
With this new instrument, we can see not only how far the smoke from the wildfires in Los Angeles reaches but also how it spreads through the atmosphere.
Lidar “ATLID”
EarthCAREs lidar ATLID is an advanced atmospheric lidar system suitable for measuring thin clouds and aerosols from above, known as vertical profiles. Lidar instruments work by sending short pulses of laser light and measuring the reflected light. A lidar detects the returning signal to determine the distance from which the light originated. These signals are then processed to obtain quantities such as the boundaries of cloud and aerosol layers, and the optical properties of the measured clouds and aerosols, such as the amount of light they absorb or block and the amount they reflect. The optical properties can be related to physical characteristics, like determining the type of aerosol (e.g., smoke or desert dust) or cloud.