Using NASA Earth Observations to Analyze Heat and Light Pollution in Urban EnvironmentsAlex Holland1 Kathryn Franks1

1Geography and Environmental Sustainability, College of Atmospheric & Geographic Sciences, University of Oklahoma, OK 73019, Alex.F.Holland-1@ou.edukfranks18@ou.edu

Two of the most visible aspects of urbanization are light pollution and

heat island effect. Light pollution occurs when an area is lit by artificial

lighting at night. The artificial light can make the sky brighter than the

normal nighttime lighting levels and disrupt circadian rhythms of many

nocturnal species. Light pollution can impact human society by

disrupting our circadian rhythms. It can affect an area for more than 50

sqkm around a major urban area. Heat pollution is otherwise known as

the “heat island effect”. This effect is caused when the rural areas

surrounding a city cool off quicker than the city itself. This can lead to a

host of ecological problems such as delaying or even halting migration

of avian species. The “heat island” effect can impact humans by not

allowing an area to cool at night leading to an increased risk of heat

exhaustion and stroke. Using Denver (CO), New Orleans (LA) and

Oklahoma City (OK) as study areas, this project analyzes these effects in

areas that have varying climates, topography and urban growth. We

evaluated night land surface temperature data from the Moderate

Resolution Imaging Spectroradiometer (MODIS) and the Visible Infrared

Image Suite (VIIRS) day/night band (DNB), to determine the light and

heat impacts of these urban areas on their surroundings. We compared

the geographic extent of these impacts for these different cities. We also

used census variables such as population, household income and land

use data to account for socioeconomic differences between the cities.

Results

Abstract

Study Areas

Conclusions

Population DataMethodology

Data

• Light pollution has a larger spatial impact than the heat island effect.

• Terrain has a significant impact on the extent of both types of pollution.

• Sprawling urban centers have a larger light pollution impact, but not necessarily a larger heat island.

• Population plays a role in heat island effect but not light pollution.

• To get the extent of the light pollution, we first found what the background value was.

• Anything above indicates human influence.

• Found the contiguous area around study areas that have above 1 nW/cm³ & created a polygon.

• The New Orleans metro polygon was split in two for the suburbs on the north shore of Lake Ponchartrain

• Temperature anomalies were found between urban area & surrounding landscape• For most areas this was between 1º C and 3º C.

• Created a polygon from the extent of the contiguous area.

• A polygon was created for New Orleans despite the LST data quality.

• The nighttime lights data for this project comes from the NPP Visible Infrared Imaging Radiometer Suite(VIIRS) Day/Night Band.

• Data from June 2015 and its units are nW/cm³. • The land surface temperature data comes from

the Terra Moderate Resolution Imaging Spectroradiometer(MODIS) collected over an 8 day span in June 2015.

• Due to influences of nearby bodies of water, the LST data quality is very low in the New Orleans study area.

Denver-Aurora Metropolitan Area

New Orleans Metropolitan Area

Oklahoma City Metropolitan Area

• This data comes from the US Census Bureau tiger shape files from 2010.

• The population density was calculated using the following formula .

• We used the Census Bureau tiger data to derive our population density map https://www.census.gov/geo/maps-data/data/tiger-line.html

• The virrs data came from the noaa VIRRS data download page. June2015 Tile 1 http://ngdc.noaa.gov/eog/viirs/download_monthly.html

• MODIS Land Surface Temperature data can be downloaded from google earth engine https://earthengine.google.org/#detail/MODIS%2FMYD11A2

• NLCD data legend and images http://www.mrlc.gov/nlcd11_leg.php

Sources

Study Area Heat Island Area (km2)

Light Pollution Area (km2)

Area (km2)

Population

Oklahoma City

982 5086 16511.48 1,549,321

Denver-Aroura 1385 4287 7644.60 2,318,833

New Orleans 1865 3336 18844.03 1,167,764

/Denver-Aurora Metropolitan Area

New Orleans Metropolitan Area

Oklahoma City Metropolitan Area