POES- NOAA Polar
Orbiter's (bad link, needs to be updated)
POES- NOAA Polar
Orbiter's (bad link, needs to be updated)
Summary information from the NOAA Polar Orbiter Data User's Guide
Platforms
NOAA Polar Orbiter systems include (TIROS N, NOAA-6, 7, 8, 9, 10, 11, 12, 13 and 14).
Sensors
The satellite system includes the following instrument package:
AVHRR - Advanced Very High Resolution Radiometer, from which is obtained:
The spectral band widths (in micrometers) of the AVHRR channels for the TIROS-N series and those proposed for the remaining spacecraft are shown in Table 3.0.1-1. In addition, the Instantaneous Field of View (IFOV) in milliradians is included for each channel in Table 3.0.1-1. The spectral response functions for each satellite are contained in the figures in Section 1.4.
Table 3.0.1-1. Spectral band widths (micrometers) of the AVHRR. |
|||||
|
Channel # |
TIROS-N |
NOAA-6,-8, |
NOAA-7,-9, |
NOAA-13 |
IFOV |
1 |
0.55-0.90 |
0.58-0.68 |
0.58-0.68 |
0.58-0.68 |
1.39 |
2 |
0.725-1.10 |
0.725-1.10 |
0.725-1.10 |
0.725-1.0 |
1.41 |
3 |
3.55-3.93 |
3.55-3.93 |
3.55-3.93 |
3.55-3.93 |
1.51 |
4 |
10.5-11.5 |
10.5-11.5 |
10.3-11.3 |
10.3-11.3 |
1.41 |
5 |
Channel 4 repeated |
Channel 4 repeated |
11.5-12.5 |
11.4-12.4 |
1.30 |
The IFOV of each channel is approximately 1.4 milliradians leading to a resolution at the satellite subpoint of 1.1 km for a nominal altitude of 833 km. The scanning rate of the AVHRR is 360 scans per minute. The time within each scan line of AVHRR data represents IFOV #1.
TOVS - TIROS Operational Vertical Sounder, which includes:
Data Characteristics
The AVHRR data are digitized to 10-bit precision. The digitized data are both transmitted from the satellite in real-time as High Resolution Picture Transmission (HRPT) data, and selectively recorded on board the satellite for subsequent playback as Local Area Coverage (LAC) data. A maximum of ten minutes of LAC data may be recorded per orbit.
In the event that a user would want SOCC to schedule an AVHRR LAC orbit over a specific area (out of direct readout range of Wallops Island or Fairbanks CDA's), the procedures and requirements are contained in Section 1.3.
Images processed by Ralph E. Meiggs, Physical Scientist, NCDC.
Polar-Orbiting Satellites (From the NOAASIS General Documentation)
Complementing the geostationary
satellites are two polar-orbiting satellites known as Advanced Television
Infrared Observation Satellite (TIROS-N or ATN), constantly circling the
Earth in an almost north-south orbit, passing close to both poles. The orbits
are circular, with an alitude between 830 (morning orbit) and 870 (afternoon
orbit) km, and are sun synchronous. One satellite crosses the equator at
7:30 a.m. local time, the other at 1:40 p.m. local time. The circular orbit
permits uniform data acquisition by the satellite and efficient control of
the satellite by the NOAA Command and Data Acquisition (CDA) stations located
near Fairbanks, Alaska and Wallops Island, Virginia. Operating as pair, these
satellites ensure that data for any region of the Earth are no more than
six hours old.
A suite of instruments
is able to measure many parameters of the Earth's atmosphere, its surface,
cloud cover, incoming solar protons, positive ions, electron-flux density,
and the energy spectrum at the satellite altitude. As a part of the mission,
the satellites can receive, process and retransmit data from Search and Rescue
beacon transmitters, and automatic data collection platforms on land, ocean
buoys, or aboard free-floating balloons. The primary instrument aboard the
satellite is the
Advanced Very High
Resolution Radiometer or AVHRR.
The polar
orbiters are able to monitor the entire Earth, tracking atmospheric variables
and providing atmospheric data and cloud images. They track weather
conditions that eventually affect the weather and climate of the United States.
The satellites provide visible and infrared radiometer data that are used
for imaging purposes, radiation measurements, and temperature profiles. The
polar orbiters' ultraviolet sensors also provide ozone levels in the atmosphere
and are able to detect the "ozone hole" over Antarctica during mid-September
to mid-November. These satellites send more than 16,000 global measurements
daily via NOAA's CDA station to NOAA computers, adding valuable information
for forecasting models, especially for remote ocean areas, where conventional
data are lacking.
Currently,
NOAA is operating two polar orbiters: NOAA-12, launched in May 1991, and
NOAA-14 launched in December 1994. A new series of polar orbiters,
with improved sensors, will begin with the launch of NOAA-K (NOAA-15) in
May 1998.
For users who want to establish
their own direct readout receiving station, low resolution imagery data is
available in the Automatic Picture Transmission (APT) service, while the
highest resolution data is transmitted in the High Resolution Picture
Transmission (HRPT) service.
How Satellites Are Named
NOAA assigns a letter to
the satellite before it is launched, and a number once it has achieved orbit.
For example, GOES-H, once in orbit, was designated GOES-7, GOES-G, which
was lost at launch, was never assigned a number. The same system is used
for polar orbiters; for example, NOAA-11, now in orbit, was designated NOAA-H
before launch. NOAA-J became NOAA-14.
For more information on
the NOAA polar-orbiting satellites, see the
Polar Orbiter Data
User's Guide, and the NOAA - J Advanced TIROS-N (ATN)
Pamphlet.
Link to the
USGS site
for more information about the AVHRR instrument. For more detailed information
about the GOES satellites, see the
GOES I-M DataBook, Revision 1, published 4 January 1997 by Space
Systems-Loral. Other sites to visit: NASAs
GOES Project
Office and POES
Project Office.
SCHEMATIC of NOAA 14 POLAR ORBIT
LOOK AT CURRENT ORBITS(http://www.fourmilab.ch/earthview/satellite.html).
NOAA-J INSTRUMENTATION
The instrument systems provide both direct readout (real time) and onboard
recording (playback) of environmental data during day and night operation.
The NOAA-J spacecraft carries the following primary instruments
(manufacturer in italics):
ADVANCED VERY HIGH RESOLUTION RADIOMETER (AVHRR) ITT
The AVHRR is a radiation-detection imager used for remotely determining cloud
cover and the surface temperature. This scanning radiometer uses five detectors
that collect different bands of radiation wavelengths as shown in Table 2.
Measuring the same view, this array of diverse wavelengths, after processing,
will permit multispectral analysis for more precisely defining hydrologic,
oceanographic, and meteorological parameters. One channel
will monitor energy in the visible band, and another channel will monitor
energy in the near-infrared portion of the electromagnetic spectrum to observe
vegetation, clouds, lakes, shorelines, snow, and ice. Comparison of data
from these two channels can indicate the onset of ice and snow melting.
The other three channels operate entirely within the infrared band to detect
the heat radiation from and hence, the temperature of land, water, sea surfaces,
and the clouds above them.
TABLE 2: Advanced Very High Resolution Radiometer (AVHRR)
SOLAR BACKSCATTER ULTRAVIOLET SPECTRAL RADIOMETER, MOD 2 (SBUV/2) Ball
Aerospace
The SBUV/2 instrument is a spectrally scanning ultraviolet radiometer. Similar
instruments were flown on NOAA-F, NOAA-H, and NOAA-I.
The SBUV/2 is capable of measuring solar irradiance and scene radiance (backscattered solar energy) over the spectral range 160 to 400 nanometers. The objectives of this instrument are-
TIROS Operational Vertical Sounder System (TOVS)
The TOVS system consists of three instruments: the HIRS/2I.
the SSU, and the MSU. All three instruments measure radiant energy
from various altitudes of the atmosphere. and the data are used to determine
the atmosphere's temperature profile from the Earth' s surface to the upper
stratosphere. Pertinent information appears in the following sections.
Stratospheric Sounding Unit (SSU) MATRA MARCONl/UK
Temperature measurements in the upper stratosphere are derived from radiance
measurements made in three channels using a pressure-modulated gas (CO2)
to accomplish selective bandpass filtration of the sampled radiances. The
gas is of a pressure chosen to yield weighting functions peaking in the altitude
range of 25 to 50 km where atmospheric pressure is from 15.5 to 1.5 mbar,
respectively. This gas is contained in three cells, one of which is located
in the optical path of each channel. Table 3 summarizes the SSU instrument
characteristics.
High Resolution Infrared Radiation Sounder (HIRS/21)
ITT
This instrument detects and measures energy emitted by the atmosphere to
construct a vertical temperature profile from the Earth's surface to an altitude
of about 40 km. Measurements are made in 20 spectral regions in the infrared
band. (One frequency lies at the high frequency end of the visible range.)
Table 4 summarizes the HIRS/2I instrument characteristics.
Microwave Sounding Unit (MSU) JPL
This unit detects and measures the energy from the troposphere to construct
a vertical temperature profile to an altitude of about 20 km. Measurements
are made by radiometric detection of microwave energy divided into four frequency
channels as shown in Table 5. Each measurement is made by comparing the incoming
signal from the troposphere with the ambient temperature reference load.
Because its data are not seriously affected by clouds, the unit is used along
with the HIRS/2I to remove measurement ambiguity when clouds are present.
TABLE 3: Stratospheric Sounding Unit (SSU)
---------------------------------------------------------------Channels--------------------------
Characteristics | 1 | 2 | 3 |
-------------------------------------------------------------------------------------------------
Spectral range(cm -1) 669.99 669.63 669.36
Equivalent bandwidth (cm -1) 2.0 1.0 0.4
Detector TGS* TGS* TGS-
Pyroelectric Pyroelectric Pyroelectric
Resolution (km at nadir) 147.3 147.3 147.3
IFOV (degrees) circular 10 10 10
NE 'delta' T at 273 K 0.25 0.5 1.25
Scan width from nadir (+/- degrees) 40 40 40
Weighting lunction peak (atmospheric 1.5 5 1.5
pressure in mbar)
------------------------------------------------------------------------------------------------
Optics-- No collecting optics, 2-in aperture.
Scanner-- 10 degree stepper for 360 degrees when in automatic calibration mode.
Data output-- 1 2-bit binary sampled at 0.48-kbps rate.
-----------------------------------------------------------------------------------
* TGS = triglycine sulfate
TABLE 4: High Resolution Infrared Radiation Sounder (HIRS/21)
Characteristics Channels
---------------------------------------------------------------------------------
1-12 13-19 20
---------------------------------------------------------------------------------
Spectral range (micrometers) 6.72-14.95 3.76-4.57 0.69
Detector HgCd Te InSb Si
Resolution (km at nadir) 20.4 20.4 20.4
IFOV (Milliradians) 24 24 24
(NE 'DELTA' N) 0.03 to 0.96 0.003 --
0.0002 to
0.001
Scan width from nadir (degrees) +49.5 +49.5 +49.5
---------------------------------------------------------------------------------
Optics-5.9-in diameter Cassegrainian telescope.
Scanner-1.8 degrees stepper, 56 scan steps then retrace.
Cooler-Two-stage radiant cooler, infrared detectors controlled at approximately 105 K.
Data output-13-bit binary, channels sampled sequentially at 2.88-kbps rate.
TABLE 5: Microwave Sounding Unit (MSU)
Characteristics Channels --------------------------------------------------------------------------------- R1 R2 R3 R4 --------------------------------------------------------------------------------- Frequency (GHz) 50.30 53.74 54.96 57.95 RF bandwidth (MHz) 220 220 220 220 Resolution (km at nadir) 105 105 105 105 NE 'delta' T (K) 0.3 0.3 0.3 0.3 Dynamic range (K) 0-350 0-350 0-350 0-350 Scan width from nadir (degrees)+47.4 +47.4 +47.4 +47.4 Antenna beamwidth (degrees)7.5 7.5 7.5 7.5 Antenna beam efficiency (%)>90 >90 >90 >90 ----------------------------------------------------------------------------------- Optics-Two scanning reflector antennas. Scanner-9.5 degrees stepper through 360 degrees scan. Data output-12-bit binary at a 0.32-kbps rate.
Space Environment Monitor (SEM) LORAL/NOAA SEL
The SEM is a multichannel, charged-particle spectrometer that measures the
population of the Earth's radiation belts and the particle precipitation
phenomena resulting from solar activity (both of which contribute to the
solar/terrestrial energy interchange). The SEM consists of two separate sensor
units and a common DPU. The sensor units are the TED and the MEPED. The
lower-energy sensors (TED, plus the proton and electron telescopes of MEPED)
have pairs of sensors with different orientations because the direction of
the particle fluxes is important in characterizing the energy interchanges
taking place.
Objectives:
Technique:
Electrical characteristics:
Performance:
SEARCH AND RESCUE (SAR) INSTRUMENTS SAR REPEATER (SARR) CRC/Canada SAR MEMORY (SARM) CNES/France The SAR instruments consist of a 3-band (121.5, 243, and 406.05 MHz) repeater SARR and a 406.025-MHz processor SARM. The SARR down link is at 1544.5-MHz and, besides the three repeated bands, also includes the 2,400 bps bit stream SARM output. MM/AS provided the antennas and interfaces and integrates the SARR and SARM into NOAA-J. The 121.5- and 406-MHz bands are also serviced by Russian COSPAS satellites which, together with the NOAA satellites, provide improved timeliness of response.
Back to Syllabus