These global composite images are created by the University of Wisconsin-Madison (UW) Space Science and Engineering Center (SSEC) Data Center. The images are a collection of approximately 14 satellites—both geostationary (GEO) and low earth-orbiting (LEO)—over the course of 1-hour intervals. Every hour, at 30min past, new imagery is uploaded to SSEC's RealEarth™ map server. Over the course of the hour the most recent satellite imagery is remapped into the composite. At any one point in each image, the source of the measurement may come from any of the satellites in the collection. Visible imagery are provided at approximately 1 km resolution.
Visible images measure scattered light. Because clouds are highly reflective (they scatter light well), they are easily seen in visible imagery. The thicker the cloud cover, the brighter it will appear in the overlay. During the nighttime, there is no sunlight to reflect and clouds are not visible: instead, use infrared imagery during the night.
time period: current; updates hourly.