meteorological sounders
DESCRIPTION
Meteorological Sounders. Dr. Bernie Connell CIRA/NOAA-RAMMT March 2005. Outline. GOES Sounder Types of soundings Channels Absorption regions (CO 2 , H 2 O, O 3 ) Retrievals (Temperature and Humidity) Derived Product Imagery (DPI) POES – Microwave sounder. - PowerPoint PPT PresentationTRANSCRIPT
CIRA & NOAA/NESDIS/RAMM
Meteorological Sounders
Dr. Bernie Connell
CIRA/NOAA-RAMMT
March 2005
CIRA & NOAA/NESDIS/RAMM
Outline
GOES Sounder
Types of soundings
Channels
Absorption regions (CO2, H2O, O3)
Retrievals (Temperature and Humidity)
Derived Product Imagery (DPI)
POES – Microwave sounder
CIRA & NOAA/NESDIS/RAMM
Passive Atmospheric Soundings
Two basic types:• Vertical sounding – the sounding instrument
senses radiation coming from the atmosphere and the earth’s surface.
• Limb sounding – the sounding instrument senses radiation in the upper atmosphere from the earth’s limb.
CIRA & NOAA/NESDIS/RAMM
Weighting function
• Derived from the vertical change of transmittance (dτ/dp)
• Specifies the relative contributions to the outgoing radiance from various levels of the atmosphere.
• Determines the layer of the atmosphere that is sensed for a given spectral channel.
• The peak occurs at the pressure level that provides the largest contribution detected by the satellite
• Contributions from individual spectral channels come from deep and overlapping layers.
Satellite Meteorology: Using the GOES Sounder
CIRA & NOAA/NESDIS/RAMMSatellite Meteorology: Using the GOES Sounder
Absorption regions for CO2, H2O, and O3
GOES Sounder Channels
ChannelCenter Wavelength
(um)
Comment (spectral region, application)
ChannelCenter Wavelength
(um)
Comment (spectral region, application)
1 14.71CO2, Stratosphereic temperature 10 7.43 Water vapor, Lower to mid-
level tropospheric moisture
2 14.37CO2, Stratosphereic temperature 11 7.02 Water vapor, mid-level
tropospheric moisture
3 14.06CO2, Upper-tropospheric temperature 12 6.51 Water vapor, upper-level
tropospheric moisture
4 13.96CO2, Mid-tropospheric temperature 13 4.57 CO2, Lower-level
tropospheric temperature
5 13.37CO2, Lower-tropospheric temperature 14 4.52 CO2, Mid-level
tropospheric temperature
6 12.66 Water vapor, lower-tropospheric moisture 15 4.45 CO2, Upper-level
tropospheric temperature
7 12.02Water vapor, “dirty” (moisture contaminated) window
16 4.13 CO2, Boundary-layer temperature
8 11.03 Window, cloud-top and surface temperature 17 3.98 Window, cloud top and
surface temperature
9 9.71 Ozone, stratospheric ozone 18 3.74 Window, cloud top and surface temperature
Visible 0.94 Visible window, cloud top and surface features
Resolution = 10 km at nadir
Lon
gwav
eM
idw
ave
Midw
ave
Shortw
ave
Satellite Meteorology: Using the GOES Sounder
CIRA & NOAA/NESDIS/RAMM
Satellite Meteorology: Using the GOES Sounder
Greatest absorption by the gas occurrs near the center of an absorption region (indicated by yellow arrows in the above diagram)This usually corresponds to colder brightness temperatures, indicating that the energy is being emitted from higher levels of the troposphere.
CIRA & NOAA/NESDIS/RAMM
Weighting Function
Satellite Meteorology: Using the GOES Sounder
1 - 14.71 um
2 - 14.37 um
3 - 14.06 um
4 – 13.96 um
5 - 13.37 um
6 - 12.66 um
7 - 12.02 um
channels 1 – 5: CO2 channels; channel 6 – low level water vaporchannel 7 – window channelNote the location and shapes of the weighting functions
Weighting Functions for 2 points: wet and dryCO2 channels 1 - 5
Weighting Functions for 2 points: wet and dryH2O channels 10 -12
10-12
CIRA & NOAA/NESDIS/RAMM
Example of all channels for the GOES-12 Sounder
CIRA & NOAA/NESDIS/RAMM
Example: Determination of Temperature profile in CO2
absorption region• Radiance to space near the center of the
absorption region (14.7 micrometers) usually corresponds to colder satellite brightness temperatures
• Away from the center of an absorption region, brightness temperatures increase as absorption by the gas decreases, and radiation from lower in the troposphere reaches the satellite.
• By selecting several spectral channels between the center and “wing” of an absorption region, the atmosphere can be probed at different depths
Satellite Meteorology: Using the GOES Sounder
CIRA & NOAA/NESDIS/RAMM
Retrieval Methods
Given a set of observed radiances, what is the temperature profile?
This is called the inverse problem or retrieval problem.
There are three general approaches to retrievals:
Physical retrievals
Statistical retrievals
Hybrid retrievals
Satellite Meteorology: Using the GOES Sounder
CIRA & NOAA/NESDIS/RAMM
Retrieval of profiles from the GOES Sounder by NESDIS (physically based)
• After cloud-clearing, the GOES Sounder radiance measurements are spatially averaged over small areas to improve signal-to-noise ratio.
• A first guess profile is obtained from a NWP model, modified by the latest hourly surface reports. Radiances are then calculated for these model first-guess profiles.
• The first-guess profiles are then adjusted until the calculated radiances match the observed GOES Sounder radiances (within some threshold).
Satellite Meteorology: Using the GOES Sounder
Radiance at Satellite = (surface blackbody radiance*surface emissivity*atmospheric transmittance)
+ atmospheric contribution from many layers.
CIRA & NOAA/NESDIS/RAMM
GOES Sounder ProductsDerived Product Imagery (DPI)
Lifted IndexCAPE
Convective Inhibition
Total Precipitable Water
Surface Skin Temperature
Water vapor winds
CIRA & NOAA/NESDIS/RAMM
Total Precipitable Water
• Utilizes “split window” technique to determine boundary-layer moisture (11.0 – 12.0 micrometer difference), and the 3 “water vapor” channels (6.5, 7.0, 7.5 micrometer) for mid-tropospheric moisture.
GOES sounder data and products
http://cimss.ssec.wisc.edu/goes/realtime/realtime.html http://www.orbit.nesdis.noaa.gov/smcd/opdb/goes/sdpi/html/sdpiimgnewt.html
Total Precipitable Water
CIRA & NOAA/NESDIS/RAMM
Lifted Index
• Utilizes retrieved temperature/moisture profile• Parcel lifted mechanically from 1000 mb level up
to 500 mb level• Operational applications: convective potential;
convective morphology
GOES sounder data and products
http://cimss.ssec.wisc.edu/goes/realtime/realtime.html http://www.orbit.nesdis.noaa.gov/smcd/opdb/goes/sdpi/html/sdpiimgnewt.html
Lifted Index
negative values – unstable air masspositive values – stable air mass
CIRA & NOAA/NESDIS/RAMM
Skin Temperature
• Utilizes longwave IR window channels (11.0, 12.0 micrometer), plus shortwave channel (3.8 micrometer) at night
• Operational applications: fog forecasting; frost/freezing temperature forecasting; highlight regions of differential heating.
GOES sounder data and products
http://www.orbit.nesdis.noaa.gov/smcd/opdb/goes/sdpi/html/sdpiimgnewt.html
CIRA & NOAA/NESDIS/RAMM
Skin Temperature
CIRA & NOAA/NESDIS/RAMM
Cloud Top Pressure
• Utilizes longwave IR window (11.0, 12.0 micrometer) and CO2 channels (13.4, 13.9, 14.1 micrometer)
• Uses visible channel and/or shortwave IR channel (4.0 micrometer) for “cloud clearing”
• Operational applications: supplement ASOS; aviation TAFs
GOES sounder data and products
http://cimss.ssec.wisc.edu/goes/realtime/realtime.html http://www.orbit.nesdis.noaa.gov/smcd/opdb/goes/sdpi/html/sdpiimgnewt.html
CIRA & NOAA/NESDIS/RAMM
Cloud top pressure
CIRA & NOAA/NESDIS/RAMM
GOES Soundings and Derived Product Imagery
Advantages:• Hourly products• Shows trends, gradients, and advection• Indicates instability prior to cloud development• A good check against models
Disadvantages• Coarse vertical resolution (only 18 IR channels)• Clouds prevent retrieval profiles• Specific (FOV) values not as indicative as trends• Potential for elevated convection not diagnosed• Product availability not timely (~1 hour past valid time)• Limited coverage
GOES sounder data and products
CIRA & NOAA/NESDIS/RAMM
POES - Microwave
• 19 – 200 GHz sensed by SSM/I and AMSU• Frequencies below 200 GHz are relatively
insensitive to cirrus clouds• Frequencies below 50 GHz lie within an
atmospheric window region and are primarily sensitive to emission by water vapor, clouds, precipitation, and surface features.
CIRA & NOAA/NESDIS/RAMM
Microwave Spectrum and Channel locations
Region for Temperature Sounding between 50 and 60 GHz
CIRA & NOAA/NESDIS/RAMM
AMSU-A AMSU-BChannel
Frequencies (GHz)
and Polarizations
Frequencies (GHz)
and Polarizations
1 23.8 R 89.0R
2 31.4R 157.0R
3 50.3R 183.3 +/- 1R
4 52.8R 183.3 +/- 3R
5 53.6R 183.3 +/- 7R
6 54.4R
7 54.9R
8 55.5R
9 57.2R
10 57.29 +/- .217R
11 57.29 +/- .322 +/- .048R
12 57.29 +/- .322 +/- .022R
13 57.29 +/- .322 +/- .010R
14 57.29 +/- .322 +/- .0045R
15 89.0R
Notation: x±y±z; x is the center frequency. If y appears, the center frequency is not sensed, but two bands, one on either side of the center frequency, are sensed; y is the distance from the center frequency to the center of the two pass bands. If z appears, it is the width of the two pass bands. Polarization: R = rotates with scan angle.
Source: Kidder and Vonder Haar (1995)
Stan Kidder’s AMSU web page at CIRA: http://amsu.cira.colostate.edu/
CIRA & NOAA/NESDIS/RAMM
SSM/TFrequency
MHzPolarization
50.5 H
53.2 H
54.35 H
54.9 H
58.4 V
58.825 V
59.4 V
Application: Vertical Temperature Sounding
Polarization: V = vertical, H = horizontal
Source: Kidder and Vonder Haar (1995)
TPW from AMSU and SSMI
3 channels centered at 183 GHzfor moisture sounding / TPW
23GHz for TPW
Weighting functions for AMSU – Bcourtesy of Tom Greenwald
Stan Kidder’s AMSU web page at CIRA: http://amsu.cira.colostate.edu/ Note: AMSU-B channels 1-5 are often referred to as AMSU channels 16-20.
C3 183.3 +/- 1R GHz
C4 183.3 +/- 3R GHz
C5 183.3 +/- 7R GHz
CIRA & NOAA/NESDIS/RAMM
AMSU Products
• Total Precipitable Water (TPW)• Cloud Liquid Water (CLW)• Rain rate• Snow and Ice cover
TPW
CLW
Rain rate
Snow cover
Ice cover
http://amsu.cira.colostate.edu/
CIRA & NOAA/NESDIS/RAMM
AMSU Products
• Microwave Surface and Precipitation Products System (MSPPS)
http://www.orbit.nesdis.noaa.gov/corp/scsb/mspps/main.html
• CIRA’s AMSU Website
http://amsu.cira.colostate.edu/
CIRA & NOAA/NESDIS/RAMM
ReferencesCDs produced by the COMET program (see meted.ucar.edu)
Polar Satellite Products for the Operational Forecaster POES Introduction and BackgroundPOES Microwave ApplicationsAn Introduction to POES Data and Products
Satellite Meteorology: Remote Sensing Using the New GOES ImagerSatellite Meteorology: Using the GOES Sounder
Kidder, S.Q., and T.H. Vonder Haar, 1995: Satellite Meteorology. Academic Press, 466 pp.Stan Kidder’s AMSU webpage at CIRA: http://amsu.cira.colostate.edu/
NOAA/NESDIS Office of Research and Applications (ORA) Operational Products Development Branch (OPDB)
Derived GOES sounder products: http://orbit-net.nesdis.noaa.gov/goes/sdpi/
The Cooperative Institute for Meteorological Satellite Studies Realtime GOES Page http://cimss.ssec.wisc.edu/goes/realtime/realtime.html
NOAA/NESDIS/ORA/Hydrology Team/Microwave Remote Sensing Project Microwave Surface and Precipitation Products System (MSPPS) http://www.orbit.nesdis.noaa.gov/corp/scsb/mspps/main.html
CIRA & NOAA/NESDIS/RAMM
Lab
Learn to navigate the following links to locate imagery for your region:
GOES Derived Product Imagery:NOAA/NESDIS/ORA/OPDB
http://orbit-net.nesdis.noaa.gov/goes/sdpi/ CIMSS
http://cimss.ssec.wisc.edu/goes/realtime/realtime.html
Stan Kidder’s AMSU webpage at CIRA: http://amsu.cira.colostate.edu/
Microwave Surface and Precipitation Products System (MSPPS)http://www.orbit.nesdis.noaa.gov/corp/scsb/mspps/main.html