Global Mapping of Global Mapping of Impervious Surface Impervious Surface

AreaArea Benjamin Tuttle* - CIRES, University of Colorado, BoulderBenjamin Tuttle* - CIRES, University of Colorado, BoulderChristopher D Elvidge, PhD - NOAA-National Geophysical Christopher D Elvidge, PhD - NOAA-National Geophysical

Data CenterData CenterKim Baugh - CIRES, University of Colorado, BoulderKim Baugh - CIRES, University of Colorado, Boulder

Ramakrishna Nemani, PhD - NASA Ames Research Center, Ramakrishna Nemani, PhD - NASA Ames Research Center, Moffett Field, California, USAMoffett Field, California, USA

Cristina Milesi, PhD - Division of Science and Environmental Cristina Milesi, PhD - Division of Science and Environmental Policy, California State University, Monterey Bay, California Policy, California State University, Monterey Bay, California

USAUSAPaul Sutton, PhD - University of Denver Paul Sutton, PhD - University of Denver

►Although exact numbers are elusive, Although exact numbers are elusive, there is a general consensus that in the there is a general consensus that in the past 30 years the world's population has past 30 years the world's population has had the highest absolute increase in had the highest absolute increase in human history. human history.

► It is agreed that more and more of the It is agreed that more and more of the world population will live in urbanized world population will live in urbanized areas leading to increases in impervious areas leading to increases in impervious surfaces world wide.surfaces world wide.

Ecological DisturbanceEcological Disturbance

►Construction of transportation Construction of transportation infrastructure and buildings can be infrastructure and buildings can be viewed as an ecological disturbance.viewed as an ecological disturbance.

►However, impervious surfaces are However, impervious surfaces are resistant to decay and often actively resistant to decay and often actively maintained.maintained.

►This means a slowed ecological recovery This means a slowed ecological recovery or succession.or succession.

Impacts of Impervious Impacts of Impervious SurfacesSurfaces

► Increased runoff of precipitationIncreased runoff of precipitation

-Alters hydrology by moving water -Alters hydrology by moving water quickly into drainagesquickly into drainages

►Displace vegetationDisplace vegetation

-Fragments vegetation cover and -Fragments vegetation cover and reduces reduces transpirationtranspiration

►Absorb sunlight without transpirationAbsorb sunlight without transpiration

-Urban heat islands-Urban heat islands

Uses for Impervious Surface Uses for Impervious Surface ProductsProducts

► Climate ModelsClimate Models

►Hydrologic Models – flood predictions, Hydrologic Models – flood predictions, definition of flood plains, sizing of sewer definition of flood plains, sizing of sewer systems to avoid overflow.systems to avoid overflow.

► Analysis of impervious surface area on Analysis of impervious surface area on water quality and morphological changes in water quality and morphological changes in stream channels and wetlands.stream channels and wetlands.

► Studies of human impact on biodiversity, Studies of human impact on biodiversity, habitat loss, and habitat fragmentationhabitat loss, and habitat fragmentation

Elvidge, C.D., C. Milesi, J.B. Dietz, B.T. Tuttle, P.C. Sutton, R. Nemani, J.E. Vogelmann, 2004: U.S. constructed area approaches the size of Ohio. Elvidge, C.D., C. Milesi, J.B. Dietz, B.T. Tuttle, P.C. Sutton, R. Nemani, J.E. Vogelmann, 2004: U.S. constructed area approaches the size of Ohio. EOS, Trans. Am. Geophys. Un.EOS, Trans. Am. Geophys. Un.: Vol. 85, 233-: Vol. 85, 233-233 233

Milesi C, SW Running, CD Elvidge, JB Dietz, BT Tuttle, RR Nemani, 2005: Mapping and modeling the biogeochemical cycling of turf grasses in the United States. Milesi C, SW Running, CD Elvidge, JB Dietz, BT Tuttle, RR Nemani, 2005: Mapping and modeling the biogeochemical cycling of turf grasses in the United States. Environmental ManagementEnvironmental Management : Vol. 36 (3), 426-438 : Vol. 36 (3), 426-438

Milesi, C., C.D. Elvidge, R.R. Nemani, and S.W. Running, 2003: Assessing the impact of urban land development on net primary productivity in the Southeastern United States, Milesi, C., C.D. Elvidge, R.R. Nemani, and S.W. Running, 2003: Assessing the impact of urban land development on net primary productivity in the Southeastern United States, Rem. Sens. Rem. Sens. Environ.: Vol. 86Environ.: Vol. 86, 401–410., 401–410.

► Increases in impervious surface area Increases in impervious surface area (ISA) have a wide spread impact on (ISA) have a wide spread impact on our environment. our environment.

Impacts on hydrologyImpacts on hydrology

Impacts on temperatureImpacts on temperature

Impacts on the carbon cycleImpacts on the carbon cycle

► In order to better understand these In order to better understand these impacts we need maps of ISA.impacts we need maps of ISA.

►Direct measurement of ISA requires Direct measurement of ISA requires high spatial resolution imagery.high spatial resolution imagery.

►Typically maps of ISA are made from Typically maps of ISA are made from high resolution imagery for small high resolution imagery for small areas.areas.

►There is a need for continental and There is a need for continental and global maps of ISA.global maps of ISA.

Mapping ISA GloballyMapping ISA Globally

►One kmOne km22 spatial resolution spatial resolution►Three data sets used:Three data sets used:

Radiance Calibrated Nighttime Lights from Radiance Calibrated Nighttime Lights from DMSP-OLSDMSP-OLS

Landscan PopulationLandscan Population USGS MRLC ISA USGS MRLC ISA

Radiance Calibrated Nighttime Radiance Calibrated Nighttime LightsLights

Created from a composite of cloud-free fixed gain imagery and converted to radiance.

Landscan PopulationLandscan Population

Census counts (at sub-national level) were apportioned to each grid cell based onlikelihood coefficients, which are based on proximity to roads, slope, land cover,and other information. LandScan has been developed as part of theOak Ridge National Laboratory (ORNL) Global Population Project for estimatingambient populations at risk.

USGS MRLC ISAUSGS MRLC ISA

USGS MRLC ISAUSGS MRLC ISA

-Created from 30m Landsat

-Impervious surfaces were extracted using a regression tree model.

Radiance Calibrated Nighttime Radiance Calibrated Nighttime LightsLights

Landscan PopulationLandscan Population

ResultsResults

►Radiance Calibrated Nighttime Lights Radiance Calibrated Nighttime Lights and Landscan Population were found and Landscan Population were found to be good predictors of ISA.to be good predictors of ISA.

►While other predictors were examined, While other predictors were examined, they were not found to be as well they were not found to be as well correlated.correlated.

ResultsResults

%ISA = (0.0747403*Radiance +%ISA = (0.0747403*Radiance +

0.0046079*Landscan)0.0046079*Landscan)

R2 = 0.6897R2 = 0.6897

Global Map of ISAGlobal Map of ISA

Global Map of ISAGlobal Map of ISA

Questions?Questions?

Download the Data:Download the Data:

http://www.ngdc.noaa.gov/dmsp/http://www.ngdc.noaa.gov/dmsp/