Background and Resource
Information for: Satellite Image Analysis on Land Use in the Arlington,VA
-Washington D.C. Area
by Sister Marie Dianne, Bishop O'Connell
High School
[Satellite Image of Impervious
Surfaces over the Baltimore-Washington D.C. area]
Source:
Subject/ Grade Level:
Grade 9 Earth and Space Integrated Science
Purpose:
To use remote sensing, geographic information systems (GIS), in-situ
measurements, and modeling to investigate Human Impact on Near surface
Atmosphere
State/ National Education Standards
and Benchmarks Addressed by this Lesson:
Abstract:
Students will be introduced to Remote Sensing Imaging of Thermal Data in
order to investigate whether growing amounts of Impervious Surfaces in
the Baltimore-Washington D.C. area are causing an increase in local atmospheric
temperatures.
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5E Lesson Model
Background
Heat
islands are areas which are
significantly warmer than surrounding vegetative or forested areas. These
areas, which are visible in thermal satellite
imagery, can raise energy and health care
costs. By studying how urbanization
impacts a local area, scientists hope to learn how to plan
cities to lower utility bills, conserve energy,
and possibly slow down or stop global warming.
A study of urban
sprawl over the past seven years, using satellite
imagery, shows that the annual photosynthetic
productivity could be lowered as much as 20
days in some mega-city areas. At Greenbelt, NASA's Goddard Space Flight
Center, Dr. Marc Imhoff combined city lights
satellite data with other data which measures
"greenness", or photosynthetic growth, both in city, suburb, and country
areas. He found a "profound
heat island effect"
Landsat
7 was launched in a
polar orbit from Vandenburg Air Force Base
on April 15,1999. One of the instruments on this spacecraft is the Enhanced
Thematic Mapper Plus (ETM+), which can transmit images with resolution
of 15 meters in the panchromatic band, 30
meters in the six visible, near, and short-wave infrared bands, and 60
meters in the thermal (heat sensing) infrared band. Landsat 7 orbits the
Earth at about 705 kilometers
in a sun synchronous orbit.
It transmits information to the EROS Data
Center (US. Geological Survey
in Sioux Falls, South Dakota) in a 16 day repeat cycle. This data can be
used by educators and students freely, and there are online tutorials to
help learners do this efficiently.
One of the applications
of Landsat 7 images is to detect and map land use/land cover, and
to detect change in land use over time. The data, tutorial, and instructional
materials are available through the Chesapeake Bay from Space web site
at: http://www.chesapeakebayfromspace.net/.
Remote Sensing means
studying something from a distance, such as studying energy reflected and
emitted from our Earth from satellites in Space.
Electromagnetic
Spectrum is a way to describe
a stream of energy photons traveling at the speed of light, which are reflected
and emitted from Earth to Space. Types of waves are characterized according
to wavelength, or frequency.
-
Visible
light waves can be sensed in the 0.4 - 0.7 microns of wavelength.
[The
longest wavelength is RED
and shortest is VIOLET.
Red, green and blue are the primary colors of the visible spectrum.]
-
The Infrared
(IR) region of the spectrum covers the wavelength
from 0.7 microns to 100 microns. [Reflected
IR covers about 0.7 microns to 3.0 micron
wavelengths. These are helpful for viewing places on Earth at night and
many other types of data.]
[Emitted, or THERMAL
IR, covers from about 3.0 microns to 100 microns.
These waves are useful for detecting sea surface temperatures and many
other types of data.]
-
The Microwave
region covers from about 1 micron to 1/1000
of a micron.
Description of the Wavelengths
and Frequencies of the Electromagnetic spectrum
Source: Canada
Centre for Remote Sensing, Ontario, Canada
http://www.ccrs.nrcan.gc.ca/ccrs/eduref/tutorial/indexe.html
Information
from remote sensing satellites like Landsat 7 can be active or passive.Active
sensors send a beam of radiation
to the target, and use the speed to calculate the distance an object is
from the source. Thus, these are helpful for determining sea surface height
and ocean floor mapping, among other things.Passive
sensors detect energy that is reflected naturally
from Earth objects.
Polar
Orbiting satellites circle the Earth in a
nearly North-South direction. They scan a swath about 300 km wide during
each orbit (120 minutes). The AVHRR (Advanced Very High Resolution Radiometer)
satellite, which provides visible and IR imagery for weather, ocean,
and land studies, and Landsat 7 are both polar orbiting satellites. Geosynchronous
Orbiting satellites, such as the Geostationary
Operational Environmental Satellites ( GOES) orbit the Earth at an altitude
of about 35,000 km (21,000 miles) above the equator, traveling at the same
speed as the Earth's rotation. This enables them to remain over the same
point on the Earth throughout its entire orbit. [Several weather satellites
are geosynchronous, and this allows they to send a series of images, which
can be turned into a time-lapse motion loop, such as one sees on the Weather
Channel each day.]
[Main
Source of Information: Conway, Eric D. and
the Maryland Space Grant Consortium, An Introduction to Satellite Image
Interpretation. Baltimore: Johns Hopkins University Press, 1997.]
Reference
WebSources for Main Concepts:
Landsat
7:
1. Goddard Space Flight Center fact sheet:
http://pao.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/landsat/landsat7.htm
and
http://ltpwww.gsfc.nasa.gov/LANDSAT/CAMPAIGN_DOCS/ANNOUNCEMENTS/L7_Writers_Guide.html
2. Photo Gallery [Earthshots] at EROS Data Center is at:
http://edcwww.cr.usgs.gov/earthshots/slow/tableofcontents
3. "Landsat
In the Classroom" http://landsat.gsfc.nasa.gov/main/education.html
Heat
Island:
1. See
7 articles listed (by clicking here)
2. "Cause,
Cost, and Correction" (by Remote Sensing Advanced
Technology)[http://satellite.rsat.com/rsat/APPS/uhi_app/UHI_DOC.html]
3. "Investigating Heat Islands in Illinois" (by
ILEED Heat Island Research Project)
Electromagnetic
Radiation:
1.Dr.Nick
Short's Introduction: http://rst.gsfc.nasa.gov/Intro/Part2_2.html
2.Canada's
Center for Remote Sensing
Website
Sources to Download Land Use Satellite Images:
1. Landsat7:
http://landsat7.usgs.gov/worldimagemap.html
2. Earthshots: http://edcwww.cr.usgs.gov/earthshots/slow/tableofcontents
3. Chesapeake
Bay from Space: Towson. edu
http://chesapeake.towson.edu/remotesensing/composite.htm
and
http://chesapeake.towson.edu/
and
http://chesapeake.towson.edu/remotesensing/raw_data.htm
4. Remote Sensing Image Archives (Univ.
of So.Carolina)
Remote Sensing Tutorials:
1. Dr.Nick Short's Online Remote Sensing
Tutorial:
http://rst.gsfc.nasa.gov/
2.
Multispec's
Online Tutorial: http://dynamo.ecn.purdue.edu/~biehl/MultiSpec/Intro5_01.pdf
3. Canada's
Center for Remote Sensing:
http://www.ccrs.nrcan.gc.ca/ccrs/eduref/tutorial/indexe.html
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Bye for now, and Thanks for joining us !!
