Geostationary and Polar Orbiting Meteorological Satellites

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Geostationary and Polar Orbiting Meteorological
Satellites

• And Basics of satellite interpretation

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Radiation in the Atmosphere
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Geo-Stationary Satellites
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GOES I M Satellites
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GOES
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GOES Satellites

• Geosynchronous orbit along equatorial plane
• 35,785 km away (22, 235 mi)
• Repeatedly view same areas
• Only 5 satellites needed for global coverage
• First launched in 1975
• NOAA day-to-day operations
• NASA builds and launches

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GOES West East(Actually GOES-E is now GOES-12)
UIUC/NCAR
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Theoretical GOES configuration
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GOES the latest

• GOES-N (13) L6/4/06 O 6/22/06
• Will be in storage at 105W, awaiting K-M failures
• GOES-M (12) L7/23/01 O4/1/03 at 75W
• GOES-L (11) L5/3/00 in storage ready 95W
• GOES-K (10) L 4/25/97 O 7/ 7/98 135W
• GOES-J (9) At 155E operational over Japan
• GOES-I (8) decommissioned drifting

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Satellite Based Cloud Patterns (1)

• Cloud element smallest cloud form resolvable on
  a satellite image
• Shields no more than 4 times as long in one
  direction as wide in another direction
• Bands Distinct Long axis more than 4 times as
  long as wide and wider than 1º Lat.
• Line Narrow cloud band under 1º Lat in which
  individual cloud elements/cells are connected.

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Satellite Cloud Patterns (2)

• Streets Narrow cloud bands in which individual
  cloud cells/elements are not connected
• Several streets, under 1 Lat, generally line up
  parallel to each other and flowing parallel to
  (along) the prevailing wind
• Fingers An extension from the forward side of a
  frontal cloud band, usually extending southward

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Visible Radiation Images

• Detect reflected sunlight from earth in the 0.4
  to 0.7 micron wavelength range.
• All clouds fog appear white/bright due to high
  albedos
• Big important exception cirrus (Ci, Cs) cloud
  may be invisible or appear wispy sometimes
• Because of high albedo clouds blend with snow
  cover on land
• Land/ocean/forests etc appear darker due to low
  albedo

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Visible Image
A VIS image is an approximation of the Earth's
albedo ( of sunlight reflected by a surface.
Light tones show high reflectivity, darker tones
show low reflectivity. Features on the surface of
the Earth or in the atmosphere vary in their
reflectivity and can be discerned on a VIS image.
No data at night.
The large, thick clouds appear white since they
have a high albedo. Thinner clouds appear light
to medium gray. The ocean, with a very low
albedo, appears nearly black. The land,
characterized by albedos that depend on the
nature of the surface, appears as various shades
of gray.
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Infrared Images

• Detects the actual temperature of surfaces such
  as the ground/ocean/cloud tops
• Ground always warm, designated darker tones and
  black
• Lower temperatures are designated brighter tones
  toward pure white

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Infrared Image
The IR sensors on board the polar orbiting and
geostationary satellites measure the amount of
infrared energy emitted by the Earth and the
atmosphere. Because the amount of energy emitted
depends on the temperature of the surface, IR
imagery is essentially a picture of the surface
and cloud top temperatures portrayed in black,
white, or gray shades. This information can be
used to observe thermal properties of the Earth
and the atmosphere. In conventional IR imagery,
colder areas appear as white or light gray tones
and warm areas appear black or dark gray.
The highest (and coldest) cloud tops appear
white. Lower clouds appear as lighter shades of
gray, and warmer land and water surfaces appear
as darker shades of gray.
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Water Vapor Channel

• High/deep clouds are white
• Low clouds are not visible
• Clear air exhibits considerable variation in
  brightness depending on the amount of mid- to
  upper-level moisture

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Water Vapor Image
Some satellite sensors study radiation at
wavelengths that are readily absorbed by the
atmosphere. Studying the IR energy at these
wavelengths allows atmospheric gas concentrations
to be studied without interference from surface
features. Energy emitted at wavelengths of 6.7
microns and 7.3 microns is absorbed by water
vapor in the atmosphere. Images taken in these
channels are used to locate large concentrations
of water vapor in the middle and upper
troposphere. The darker regions are areas where
very little water vapor exists in the middle and
upper troposphere, and the lighter regions are
moist.
Water vapor imagery shows moisture in the
atmosphere, not just cloud patterns. This allows
meteorologists to observe large-scale circulation
patterns even when clouds are not present.
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Detecting Cloud on Infrared Images

• Low clouds (St, Sc, Ns, fog) are warmer due to
  closeness to ground
• Blend in with ground and may be invisible or at
  least hard to see
• High Clouds (Ci, Cs, Cu tops of Cbs) are very
  cold and very white
• Stand out very clearly on IR, but remember they
  are hard to see (Cirrus) on visible

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Cloud Detection from satellite

• Low Clouds and fog
• Visible on visible, (near) invisible on Infrared
• High Cirrus
• (near) invisible on Visible, bright on Infrared
• Cumulonimbus tops
• Visible on both Vis and IR
• Alto-level clouds (As, Ac)
• Very tough to discern from space, no clear rules

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What is this?
http//www.rap.ucar.edu/weather/satellite/
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What this is
Snow
Snow
Cirrus
Cirrus
Stratus
Stratus
Snow is reflective, but not too cold. Stratus in
Mississippi is the same, and the wispy but cold
values in Ontario are cirrus
http//www.rap.ucar.edu/weather/satellite/
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What is this?
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What this is
Cumulus
Cumulus
Cumulo Nimbus
Cumulo Nimbus
Cirrus
Cirrus
The low (warm) and scattered clouds in Georgia
are cumulus. The scattered by higher clouds in
central Florida are cumulonuimbus. The wispy
clouds southwest of Florida are cirrus clouds
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What this is
Cumulus
Cumulus
MCN
MCN
Cumulo Nimbus
Cumulo Nimbus
TPA
TPA
NQX
NQX
Cirrus
Cirrus
KMCN 272053Z 28008KT 10SM FEW055 33/19 A2999 RMK
AO2 SLP152 T03280194 58023 KTPA 272053Z 01015KT
6SM TS HZ FEW020 BKN040CB BKN080 OVC250 28/23
A3005 RMK AO2 TSB45 SLP175 FRQ LTGICCG TS OHD-N
MOV S TCU E VCSH VIS LWR N T02780228 56015 KNQX
271955Z 11008KT 6SM HZ SCT020 BKN080 BKN250 30/24
A3006 RMK SLP181 T03000244
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