Holiday lights when seen from the ground give us cheer and help us celebrate the season.

But from space, over time, they can tell us something about both culture

and energy usage. Three years ago

a new satellite called Suomi NPP began to give us brilliant new views of the Earth

by day and by night. But as stunning as it is

to see Earth all aglow, this is still just one composite image

averaging observations over a period of months. Getting the

big picture from space is always helpful, but we can learn even more

seeing that picture change over time.

A NASA-lead team of researchers has been pouring over the data from NPP

and compensating for factors like the reflection of the moon and the effect

terrain, clouds, aerosols, to produce a scientifically-valuable

measuring Earth’s lights on a daily basis.

The first thing they noticed in the data was the effect of holidays.

Román:When we started looking at the data at night over the

we were expecting to see a lot of stability in the night time lights.

And we were really surprised to see this really vibrant increase

in activity during the holidays particularly around

areas in the suburbs.You have a lot of single-family homes

with a lot of yard space to put in lights.

Narrator:Comparing the six weeks between Thanksgiving and New Years to the rest of the year,

the team noticed large areas where night lights were 20, 30, even 50 percent

brighter over the holidays, as shown here in shades of green.

Román:And so what we are seeing is this shift in location

in activity where people are staying in their homes

and they’re celebrating, or they’re traveling to the rural areas

and they’re celebrating … and they’re turning on the lights

. Whereas in the urban centers people are turning off the lights because they’re going off for the holidays.

Narrator:

Researchers actually first saw changes in holiday lighting patterns during Ramadan in the Middle East.

Román:In contrast to the western holidays of Christmas and New Years, during Ramadan

you don’t see a shift in activity in location. What you’re seeing is that communities

are staying where they are, and they’re shifting their activities

to the nighttime.

Another thing that the … measurements are telling us is that it’s capturing cultural differences even

within a single community like the Muslim community

during the month of Ramadan. We’re seeing patterns in behavior

that varies significantly from country to country,

a smaller increase in nighttime lights in Turkey, large increase of nighttime lights in

Saudi Arabia, no increase in nighttime lights in Israel

because it’s not a predominantly Muslim country. So it’s a lot of diversity seen within the data.

Narrator:Because the night light data has such good resolution,

researchers from Yale University have even been looking at

neighborhoods within cities, and correlating that data with known political and

socio-economic factors.

But from a NASA perspective, why is it important to concentrate on Earth’s lights from space?

Román:A lot of our capability focuses on

using satellites to get a global picture of where we are

with respect to the environment and with respect to the day-to-day processes

processes that drives the earth system. A big component of that is

human activity and how they are driving the different processes

that impact the earth like carbon emissions and

like the heating patterns across cities.

So by looking at the lights we can see changes in human behavior

throughout the seasons, throughout the days, and we can use

that information to then understand what are the

norms that are driving the decisions behind

energy. If you look at climate change

research right now, we know that more than 70 percent of emissions

are happening in cities. So NASA is putting a lot of emphasis

on understanding cities and understanding the dynamics

dynamics of how cities are interacting with the climate and our system as a whole.

[music]

[music]