Appreciation of Earth Observing Systems

AVHRR on NOAA

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AVHRR on NOAA

Question 1

Into what general category of EOS does the instrument fall?

The Advanced Very High Resolution Radiometer (AVHRR) provides four to six band multispectral data

Question 2

What capture technology is used?

The AVHRR is a six channel scanning radiometer

Question 3

Is the sensor active or passive?

Passive system

Question 4

At what wavelength(s) does the sensor function?

Channel Number Wavelength(um)

1 0.55-0.68

2 0.725-1.00

3A 1.58-1.64

3B 3.55-3.93

4 10.30-11.30

5 11.50-12.50

Question 5

What resolution does the sensor have – temporal and spatial?

Temporal

1.1km
Spatial

The orbital period is about 102 minutes which produces 14.1 orbits per day. Because the number of orbits per day is not an integer, the sub-orbital tracks do not repeat on a daily basis, although the local solar time of the satellite's passage is essentially unchanged for any latitude.

Question 6

Is the sensor carried on an airborne or spaceborne platform? What is that platform – typically?

The Sensor is carried on the National Oceanic and Atmospheric Administration (NOAA) Spaceborne satellites.

Satellites Launch Date End Mission AVHRR version

NOAA 6 27/6/79 16/11/86 1
NOAA 8 Failed launch
NOAA 7 23/6/81 7/6/86 2
NOAA 8 28/3/83 31/10/85 1
NOAA 9 12/12/84 11/5/94 2
NOAA 10 17/9/86 Operational 1
NOAA 11 24/9/88 13/9/94 2
NOAA 12 14/5/91 15/12/94 1
NOAA 13 Unoperational after 12 days
NOAA 14 30/12/94 Operational 2
NOAA 15 13/5/98 Operational* 3
NOAA 16 21/10/00 Operational 3

Sync problem affecting image quality experienced starting July 9/10, 2000

Question 7

Who developed/launched/manages the sensor?

The sensor is developed/launched and managed by The National Oceanographic and Atmospheric Administration (NOAA)

Question 8

Can data be purchased from service providers?

Data can be purchased from the U. S. Geological Survey (USGS). Data from 1996-1999 can be downloaded for free. Other data can be purchased on CD or DVD for $190 USGS

Question 9

What products are available?

The Raw (free) data consists of single scene that was controlled by a single AVHRR satellite. The images are of areas 2400 x 6400 kilometers.

The Georegistered data consists of radiometrically ang geometrically corrected single scene AVHRR data that is processed according to user-specified parameters such as projection, resampling method and pixel size. The data is available in binary (8- or 10- bit) format. Data can also be purchased from NASA, NOAA, ESA, CSIRO & SMC.

Question 10

At which main application areas is the sensor aimed?

The primary purpose of these instruments is to monitor clouds and to measure the thermal emission of the earth. It has also been used for studying climate, climate change, cloud and vegetation cover.

List 2 specific projects, where they have been reported, their goals and their outcomes.

In 1992 the 1-km AVHRR global land dataset was produced for the first time between the 21st & 30th of June. It comprised of over 40,000 AVHRR images covering all land areas on earth. NASA, NOAA, ESA and the USGS were all involved in the project which required 23 global stations to complete the data collection. The major uses of the composites are related to the study of surface vegetation cover. The data collection continues today as the 1-km AVHRR global land dataset is being continually being updated.

The AVHRR Polar Pathfinder Twice-Daily 5 km EASE-Grid Composites are a collection of products for both poles, consisting of twice-daily gridded and calibrated satellite channel data and derived parameters. The satellite records clear sky surface broadband albedo and skin temperature, solar zenith angle, satellite elevation angle, sun-satellite (UTC) of acquisition of the two poles. This project ran from July 1981 to August 1998.