Chapter 2: Satellite Tools for Air Quality Analysis

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Chapter 2 Satellite Tools for Air Quality
Analysis

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Main Applications of Satellite Tools for Air
Quality

• Public Health
• Monitor air quality in areas where there is no
  ground-based network
• Advanced warning of major regional events (e.g.,
  fires)
• Information about the transport of pollutants
• Outreach and Awareness
• Visual appeal images help communicate air
  quality information to the public and
  policymakers
• Blog de Calidad del Aire

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Main Applications of Satellite Tools for Air
Quality

• Air Quality Event Analysis
• Archived images and data aid in retrospective
  analysis of air quality events
• Air Quality Forecasting
• Official predictions of the next days air
  quality
• Designed to protect public health

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Satellite Data Products for Air Quality Analysis

• MODIS true color images
• MODIS aerosol optical depth (AOD)
• GASP (GOES AOD)
• OMI sulfur dioxide (SO2)
• OMI nitrogen dioxide (NO2)
• Hazard Mapping System Fire and Smoke Product

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MODerate Resolution Imaging Spectroradiometer
(MODIS)

• 36 spectral bands ranging from 0.41 to 14.385 mm
• Many applications, including air, water,
  vegetation
• Spatial resolution of 1 km, 500 m, and 250 m
• MODIS is on NASAs Terra and Aqua satellites

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MODIS True Color Image

• A true color image is NOT a picture!
• It is made from a combination of the red (band
  1), green (band 4), and blue (band 3) bands of
  MODIS

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MODIS True Color Image
MODIS TerraJuly 6, 2002

• Smoke
• Haze
• Clouds

• Sunglint
• Snow
• Clear sky

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MODIS True Color Image
CLOUDS
SMOKE
MODIS AquaMarch 18, 2005
SUNGLINT
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MODIS Aerosol Optical Depth (AOD)

• AOD is a measure of the scattering and absorption
  of light by particles in a vertical column of the
  atmosphere
• AOD is proportional to particulate concentration
• AOD is dimensionless higher values correspond to
  high particulate concentrations
• Clouds block the measurement of AOD!

Sun
Particles in atmosphere scatter and absorb light
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MODIS Aerosol Optical Depth (AOD) Image
Smoke
Haze
MODIS Terra August 1, 2007
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MODIS Aerosol Optical Depth (AOD) Image
Smoke
MODIS Aqua April 27, 2008

• Red high particulate concentration
• Blue low particulate concentration

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Northern India, Nepal, and BangladeshMODIS True
Color and AOD Images
Haze
Haze
MODIS Terra February 5, 2006
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GOES Aerosol and Smoke Product (GASP)

• GASP is AOD derived from the GOES geostationary
  satellites
• GASP is being developed for Central America and
  the Caribbean only experimental images are
  currently available
• Advantage of GASP is that it is available every
  30 minutes (high temporal resolution)

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Ozone Monitoring Instrument (OMI)

• Measures UV and visible radiation backscattered
  from Earth
• Designed to monitor important air quality
  components including O3, NO2, SO2, and aerosols
• Spatial resolution of 13 x 24 km
• OMI is on NASAs Aura satellite

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OMI Sulfur Dioxide (SO2)

• Used primarily to monitor volcanic eruptions
• Measured in Dobson Units (DU)
• Vertical column measurement
• Clouds block the measurement of OMI SO2!

SO2
Popocatepetl
1 DU 2.6871016 cm-2
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OMI Sulfur Dioxide (SO2)
SO2
Columbia
SO2
Ecuador
Peru
1 DU 2.6871016 cm-2
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OMI Nitrogen Dioxide (NO2)

• Vertical column measurement
• Clouds block the measurement of OMI NO2!
• Grey areas indicate missing data due to cloud
  cover

NO2
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OMI Nitrogen Dioxide (NO2)

• New OMI NO2 product zoom in on Central America
  and the Caribbean!
• Many grey areas due to cloud cover during the
  rainy season

NO2
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Hazard Mapping System (HMS)Fire and Smoke Product

• Trained analysts use data from GOES, MODIS, and
  other satellites to map smoke and fire locations
• Year-round analysis for USA by NOAA
• Analysis for Mexico, Central America, Cuba, and
  the Bahamas during the fire season (March June)
  by Servicio Meteorológico Nacional de México

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HMS Fire and Smoke Product

• Analysis made 1 pm 11 pm daily
• Red dots are hotspots identified by MODIS
  (fires)
• Smoke plumes are grey
• Countries outlined in green are the focus of the
  analysis

May 25, 2008
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Navy Aerosol Analysis and Prediction System
(NAAPS) Global Aerosol Model

• NAAPS is a global forecast model that predicts
  the concentrations of sulfate, dust, and smoke
  aerosols in the troposphere.
• NAAPS is run by the U.S. Naval Research
  Laboratory in Monterey, California.
• Meteorological information is provided by the
  Navy Operational Global Atmospheric Prediction
  System (NOGAPS) numerical forecast model.
• Information on distribution of aerosols is
  provided by individual sulfate, smoke, and dust
  emissions models.

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Navy Aerosol Analysis and Prediction System
(NAAPS) Global Aerosol Model

• Model aerosol forecasts are provided
• On a 1 1 grid
• At 6-hour intervals
• Out to 120 hours (5 days)
• For more information on the technical aspects of
  NAAPS, visit http//www.nrlmry.navy.mil/aerosol/in
  dex_frame.html.
• Model output is a 4-panel graphic available as
• Current day forecast
• 5-day forecast
• 5-day forecast loop in 6 hour intervals

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NAAPS 4- Panel Forecast Graphic
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Interpretation of the NAAPS 4-Panel Graphic

• Upper left of panel Total Optical Depth of
  sulfate, dust, and smoke aerosols.
• Optical depth of aerosols in entire troposphere!
• Types of aerosols are color-coded for easy
  interpretation.
• DO NOT focus on this panel, since it is NOT a
  surface analysis!

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Interpretation of the NAAPS 4-Panel Graphic

• Upper right of panel Concentration of Sulfate at
  the surface in mg/m3.
• Concentration values are color-coded for easy
  interpretation.
• Sulfate aerosols are a main component in urban
  haze.
• DO focus on this panel, because it is a surface
  analysis!

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Interpretation of the NAAPS 4-Panel Graphic

• Lower left of panel Concentration of dust at the
  surface in mg/m3.
• Concentration values are color-coded for easy
  interpretation.
• Dust can be transported across the Atlantic from
  Africa and impact the region.
• DO focus on this panel, because it is a surface
  analysis!

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Interpretation of the NAAPS 4-Panel Graphic

• Lower right of panel Concentration of smoke at
  the surface in mg/m3.
• Concentration values are color-coded for easy
  interpretation.
• Smoke is a major issue in the region during the
  dry season.
• DO focus on this panel, because it is a surface
  analysis!

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Activity 2 Air Quality Satellite Products

• Participants should break into groups of 3-4.
• Each group will be given a packet of satellite
  images.
• For each image, participants should determine
• Satellite and instrument that made the
  measurement
• Pollutant or product represented in the image
• Main air quality features (e.g., locations of
  high concentrations of pollutants
• After the team analysis, we will come back
  together as a large group to discuss the images.
• Goal become familiar with air quality satellite
  images.