Night time light is an effective indicator of stable human activity. This map illustrates current radiance per pixel (from 2016) as well as increases and decreases (toggle the layers on and off to see). Distinct increases can be seen in cities around the LA metropolitan area, but there are also encouraging decreases in parks and protected areas.
From 1992 to 2012, the National Park Services collaborated with other federal and state agencies to reduce light pollution and ecological harm from other forms of human activity in protected areas. Their protective strategies have led to significant improvements: a significant decrease in stable night time light can be seen within the Santa Monica Mountain National Recreational Area and San Gabriel Mountains.
This map was created using NOAA images of stable nighttime light, which have helped us track changes in human access to the wilderness for the past 20 years. In 2013, a new satellite product became available that will continue to make tracking possible.
Data source: 2016 nighttime light data from Earth Observation Group, NOAA National Centers for Environmental Information (NCEI). Change in nighttime light statistics by Shenyue Jia, UCLA, using DMSP data from NOAA’s National Geophysical Data Center. DMSP data collected by US Air Force Weather Agency.