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