Satellite Remote Sensing for Air Quality Analysis in Central America

1
Satellite Remote Sensing for Air Quality Analysis
in Central America
Dr. Ana Prados UMBC/JCET Ana.I.Prados_at_nasa.gov 301
-614-5494

• Dr. Amy K. Huff
• Battelle Memorial Institute
• huffa_at_battelle.org
• 703-875-2975

Betzy Hernandez CATHALAC betzy.hernandez_at_cathalac.
org
2
Acknowledgements

• NASA Applied Sciences Program Lawrence A.
  Friedl, Daniel E. Irwin
• U.S. EPA Orlando Gonzales, Lourdes Morales
• National University José Félix Rojas, Jorge
  Herrera
• CATHALAC Emil Cherrington, Francisco Delgado,
  Africa Flores, Eric Anderson, Valerie Garrish
• University of Panama Vasco Duke, Hipólito
  Guerra, Wilfredo Urriola
• University of Maryland, Baltimore County Ray
  Hoff, Hai Zhang, Ruben Delgado, Nikisa Jordan

3
Chapter 1 Satellite Remote Sensing of the Earth

• 900 930

4
What is Remote Sensing?
Remote sensing is a method of obtaining
information about the properties of an object
without coming into physical contact with it.
5
Why use Satellites to Study the Earth?

• Consistent, routine, global measurements
• Overview of information on the hemispheric,
  regional, national, and local scales the big
  picture
• Provide information in areas where there are no
  ground-based measurements
• Advance warning of impending environmental events
  and disasters
• Visual appeal a picture is worth a thousand
  words

6
Satellites Provide a Global View
Satellite data are used for many applications,
including monitoring global weather, studying
climate change, and observing the environment.
7
A Picture is Worth a Thousand Words!
Satellites provide consistent, routine, global
coverage of environmental events
8
Important Satellite Characteristics Spatial
Resolution

• Spatial resolution is the smallest area on Earth
  that a satellite can observe.
• Depends on the type of instrument
• Low spatial resolution (e.g., 10 km) can
  seelarge regional features (cities, forests,
  lakes)
• High spatial resolution (e.g., 10 m) can see
  detailed features (buildings, roads, trees)

9

• Low spatial resolution (1 km)
• Major regional features are visible (rivers,
  urban areas, clouds)
• Detailed features are NOT visible!

10

• High spatial resolution (10 m)
• Detailed features are visible!
• Usually high spatial resolution images are
  expensive!!

11
Important Satellite Characteristics Temporal
Resolution

• Temporal resolution is how frequently a
  satellite observes the same area on Earth.
• Depends primarily on the orbit of the satellite
• High temporal resolution (e.g., 30 minutes)
  nearly continuous observations
• Low temporal resolution (e.g., 1 day) only one
  observation per day

12
Geostationary Satellites

• In high altitude orbit (35,800 km)
• Orbital period of satellite matches rotational
  speed of Earth
• Continuously observe same area on Earth
• Very high temporal resolution (minutes hours)
• Usually used to monitor meteorological conditions
  and severe storm development, including
  hurricanes, tornadoes, and floods

13
Geostationary Environmental Operational
Satellites (GOES)

• U.S. geostationary weather satellites
• Temporal resolution 30 min 3 hours
• Spatial resolution 1 km, 4 km, and 8 km
• 5 bands
• Visible (0.55-0.75 mm)
• Shortwave IR (3.80-4.00 mm)
• Water Vapor (6.50-7.00 mm)
• IR 1 (10.20-11.20 mm)
• IR 2 (11.50-12.50 mm)

GOES-East
GOES-West
14
Examples of Geostationary Satellites
15
Polar-Orbiting Satellites

• In low altitude orbit (700-800 km)
• Orbit around North and South Poles
• Earth rotates under satellite as it orbits, so
  each time satellite makes a pass over Earth, it
  observes a new area
• Polar-orbiting satellites observe same area on
  Earth once per day (or less)
• Low temporal resolution
• Global coverage!
• Used for a variety of applications, including air
  quality, land cover, water quality, and
  vegetation studies

16
NASAs Polar-Orbiting Satellites
17
NASA Air Quality Polar-Orbiting Satellites

• Terra
• Launched in 1999
• 1030 AM local overpass
• Aqua
• Launched in 2002
• 130 PM local overpass
• Aura
• Launched in 2004
• 130 PM local overpass

18
The A-Train Afternoon Overpass Polar-Orbiting
Satellites
19
How Do Satellites Make Measurements?

• Satellites do not make direct measurements of
  the Earths geophysical parameters.
• Instead, satellites measure solar and/or
  terrestrial radiance (light) in a vertical column
  of the atmosphere.
• Radiance data are converted into geophysical
  parameters using science-based algorithms.

20
Satellite Remote Sensing of Earth Challenges

• Satellites are very expensive to build and
  launch.
• No direct measurements radiance (light)
  measurements must be converted to geophysical
  parameters, such as temperature or pollutant
  concentration.
• Tradeoffs between spatial and temporal
  resolution.
• Advantages far outweigh the challenges!

21
Activity 1 Satellite Orbits

• Participants should break into groups of 3-4.
• Each participant will be given a worksheet on
  satellite orbits.
• Participants should work with their group to
  answer the questions.
• After the team analysis, we will come back
  together as a large group to discuss the
  questions.
• Goal become familiar with satellite terminology
  and characteristics.