climate, meteorology and atmospheric chemistry
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Climate, Meteorology and Atmospheric Chemistry
Atmospheric Applications of Multi and Hyperspectral
Remote Sensing
Weather monitoring and forecastingCloud type identificationClimate studies
Atmospheric contributions to climateLand-atmosphere interactionsOcean-atmosphere interactions
Atmospheric chemistryPollution monitoringVolcanic ash, other aerosolsActive Remote Sensing (Radar) – many
weather apps.
Applications of satellites for atmospheric studies
Von Karman Vortices
Hurricane Fran, 1996
MODIS ImageSaharan dust moving across Mediterranean to Turkey
Sulfur Dioxide Plume – Kahlua
Earliest man-made satellites were designed for weather observationsVanguard 2 (1959) – designed to measure cloud
cover but didn’t work wellTIROS 1 (1960) – crude weather observations
allowed scientists to view earth’s weather as a system
Application Technology Satellites (1966) – full disk view of earth
Nimbus satellites (1964 – 78) – atmospheric temperature and ozone profiles and other atmospheric propertiesNimbus set the stage for modern satellite remote
sensing
Meteorological RS: Early History (Review)
Defined by orbital characteristicsPolar orbiting – travel roughly over poles on
each orbitTypically two views/day of each place on earthRelatively high spatial resolution due to lower
altitude than geostationaryGeostationary – orbit parallel to the equator at
an altitude of 22,300 miles; always over one place.Full hemisphere or large area viewing but usually
at lower resolution due to altitude
Types of weather satellites
GOES – Geostationary Operational Environmental SatellitesGOES 12 also called GOES East – over Brazil
but captures imagery for our entire hemisphere
GOES 11 also called GOES West – over eastern Pacific Ocean
NOAA operates several polar orbiting weather satellites (NPOES)
Many other countries have their own weather satellites that are either polar orbiting and geostationary
Modern weather satellites
GOES Composite Image of USWarm (low) clouds bluish, Cold (high) clouds yellow and red.
GOES West ImageThermal IRFull DiskApril 6, 2015
GOES East full diskVisibleApril 6, 2015
Interpretation of visible (panchromatic) imagesCloud and aerosol thicknesses
Interpretation of infrared imagesCloud temperatures and heights
Prognostication (prediction)Time-lapse views that show movement of
systemsHurricane tracking and monitoringData inputs for weather models
How are weather satellites used?
Can see clouds (bright) and relative cloud thickness (brighter = thicker until saturation)
Can see haze and aerosol (relatively bright)Cannot distinguish cloud heights (low, middle
and high altitude clouds all look the same)
Visible wavelength satellite imagery
Visible can only be used in the daytime
Long-wave IR (thermal) allows sensing of the temperature of the cloud tops--related to heightHigher cloud tops colder than low cloud tops
IR satellite imagery
IR Weather images are processed so that coldest places appear BRIGHT and warmest appear DARKOpposite of normal thermal imagery!!
Can be used day or night.
Features Typicallywith a
RelativelyHigh Temperature
Features Typicallywith a
RelativelyLow Temperature
Snow/ice surfaces
Land surfacesat low elevations
<---> Land surface
at high elevations
Land and ocean surfaces at low latitudes
<---> Land and ocean surfaces
at high latitudes
Land surfaces in early/mid afternoon
<---> Land surfacesnear sunrise
[Land surfacesin mid/late summer
<---> Land surfaces
in mid/late winter]*
[Ocean surfacesin late summer
<---> Ocean surfaces
in late winter]**
IR Satellite imagery can also be used to create images of the amount of water vapor in the atmosphere
Water vapor images
Several satellites have bands that are useful for atmospheric chemistry (e.g., MODIS) or are completely dedicated to the atmosphere (e.g., AURA)Aura flies “in formation” about 15 minutes
behind MODISAura carries several instruments that measure
different constituents of the atmosphereOther satellites
TOMS – Total Ozone Mapping SpectrometerUARS – Upper Atmosphere Research Satellite
Remote sensing for monitoring atmospheric chemistry
Human activities have changed the composition of the atmosphere since the pre- industrial era
Note: Ground based sensors are used more than satellite sensors for atmospheric chemistry (and pollution)Can look outwards just as a satellite looks
downwards and measure amount of light in various wavelengths
Atmospheric absorption of particular wavelengths indicative of particular chemicalsStrength of absorption relates to concentration of
chemical
Value of space based sensors is more in getting whole-atmosphere view; Ground based sensors limited spatially
Ground based sensors
Satellites can measure and track plumes of air pollutionE.g., MOPITT – Measurements Of Pollution In
The TroposphereMeasures amount of carbon monoxide and
methane in the atmosphereMany satellites for atmospheric chemistry can
also measure some pollutants
Air pollution monitoring with satellites
Photo by Mark Gocke, Casper Star Tribune.
Global carbon monoxide during MOPITT’s first year of operation
CO produced by burning of fossil fuels, volcanoes, wildfire, etc.
Satellites are critical for weather forecasting and climate studiesOptical data primarily used for cloud studiesThermal IR data also extremely useful (will
discuss thermal later in semester)Atmospheric chemists use satellites for global
and local monitoringAtmospheric pollution is a subset of
atmospheric chemistrySatellites allow mapping of general pattern of
pollutant concentration and tracking of plumes, etc.
Summary
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