sciencetech-blog

comments

Cities really are brighter places during the holidays, Nasa has revealed.

In a series of stunning images, it found the holidays can cause a cities lights to be boosted by 50%.

The series of pictures shows Christmas and New Year's in the United States and the holy month of Ramadan in the Middle East.

Scroll down for video 

City lights shine brighter during the holidays in the United States when compared with the rest of the year, as shown using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where lights are 50 percent brighter, or more, during December.

'Even from space, holidays shine bright,' Nasa said.

Researchers analysed daily data from the NOAA/Nasa Suomi National Polar-orbiting Partnership (Suomi NPP) satellite.

They were able to track how patterns in nighttime light intensity change during major holiday seasons – Christmas and New Year's in the United States and the holy month of Ramadan in the Middle East.

Around many major U.S. cities, nighttime lights shine 20 to 50 percent brighter during Christmas and New Year's when compared to light output during the rest of the year, as seen in the satellite data. 

In some Middle Eastern cities, nighttime lights shine more than 50 percent brighter during Ramadan, compared to the rest of the year.

The new analysis of holiday lights uses an advanced algorithm, developed atNASA's Goddard Space Flight Center in Greenbelt, Maryland, that filters out moonlight, clouds and airborne particles in order to isolate city lights on a daily basis. 

The data from this algorithm provide high-quality satellite information on light output across the globe, allowing scientists to track when – and how brightly – people illuminate the night. 

In the United States, the lights started getting brighter on 'Black Friday,' the day after Thanksgiving, and continued through New Year's Day, said Miguel Román, a research physical scientist at Nasa Goddard and member of the Suomi NPP Land Discipline Team, who co-led this research.

He and his colleagues examined the light output in 2012 and 2013 in 70 U.S. cities, as a first step in determining patterns in urban energy use – a key factor in greenhouse gas emissions.

In most suburbs and outskirts of major cities, light intensity increased by 30 to 50 percent. 

Lights in the central urban areas did not increase as much as in the suburbs, but still brightened by 20 to 30 percent.

'It's a near ubiquitous signal. Despite being ethnically and religiously diverse, we found that the U.S. experiences a holiday increase that is present across most urban communities,' Román said. 

'These lighting patterns are tracking a national shared tradition.'

Because snow reflects so much light, the researchers could only analyze snow-free cities. 

They focused on the U.S. West Coast from San Francisco and Los Angeles, and cities south of a rough imaginary line from St. Louis to Washington, D.C. 

The team focused on the U.S. West Coast from San Francisco and Los Angeles, and cities south of a rough imaginary line from St. Louis to Washington, D.C. 

The new analysis of holiday lights uses an advanced algorithm, developed atNASA's Goddard Space Flight Center in Greenbelt, Maryland, that filters out moonlight, clouds and airborne particles in order to isolate city lights on a daily basis.

The team also examined lighting patterns across 30 major towns in Puerto Rico, known for its vibrant nocturnal celebrations and for having one of the longest Christmas holiday periods.

'Overall, we see less light increases in the dense urban centers, compared to the suburbs and small towns where you have more yard space and single-family homes,' said Eleanor Stokes, a Nasa Jenkins Graduate Fellow and Ph.D. candidate at Yale University's School of Forestry and Environmental Studies, New Haven, Connecticut, who co-led the study with Román.

These new results, illustrating holidays in lights, were presented at the American Geophysical Union's Fall Meeting in San Francisco. 

The idea to look at holiday light-use patterns stemmed from one of the first analyses of the new daily lights algorithm, Román said. Colleagues from Nasa Goddard and Yale were looking data of Cairo in 2012 and noticed a large discrepancy.

'Either you have something going on with your data that's wrong, or there's a real signal there that you have to look into,'Román recalls them saying.

When the team investigated the satellite record, they found that the large increase in light output in Egypt's capital corresponded with the holy month of Ramadan. 

During Ramadan, Muslims fast during the day, pushing meals and many social gatherings, markets, commerce and more to nighttime hours. 

In several cities in the Middle East, city lights brighten during the Muslim holy month of Ramadan, as seen using a new analysis of daily data from the NASA-NOAA Suomi NPP satellite. Dark green pixels are areas where the lights are 50 percent brighter, or more, during Ramadan.

To confirm that the nighttime signal was not merely an instrument artifact, they examined three consecutive years worth of data from 2012 through the fall of 2014. 

They found that the peaks in light use closely tracked the Islamic calendar, as Ramadan shifted earlier in the summer.

But not all Middle Eastern cities responded the same as Cairo. Light use in Saudi Arabian cities, such as Riyadh and Jeddah, increased by about 60 to 100 percent through the month of Ramadan. 

Light use in Turkish cities, however, increased far less. Some regions in Syria, Iraq and Lebanon did not have an increase in light output, or even demonstrated a moderate decrease, possibly due to unstable electrical grids or conflict in the region.

'Even within majority Muslim populations, there are a lot of variations,' Stokes said. 

'What we've seen is that these lighting patterns track cultural variation within the Middle East.'