SeaWiFS
(Sea-viewing Wide Field of view Sensor)

Introduction

The SeaWiFS mission is a part of NASA's Mission to Planet Earth (MTPE), which is designed to look at our planet from space to better understand it as a system in both behavior and evolution.

The Sea-viewing Wide Field-of-view (SeaWiFS) Sensor is carried on the SeaStar spacecraft, launched on 1st August 1997. You can view the first SeaWiFS pass received at Dundee (16 September).

The SeaWiFS scanner differs from the AVHRR scanner in that it can tilt to avoid sunglint on the sea (the CZCS scanner tilted in a similar way). We have an example image of the scanner tilting mid-way through a pass on 31 May 1998 at 13:03.

Obtaining SeaWiFS data

Dundee Satellite Receiving Station is receiving and archiving the data from SeaWiFS. As there are restrictions on the use of the data you are required to register before being allowed to view images and place orders.

Frequently Asked Questions

  1. Why are the passes shorter in winter than in summer?

    The SeaWiFS sensor is turned off when the sun angle is too low (solar zenith is greater than 72.7 degrees). This occurs in the northern hemisphere during the winter. As the sensor is designed for viewing ocean colour in visible wavelengths, a significant energy saving can be made by turning the sensor off during the dark regions.

  2. I have upgraded my account to view SeaWiFS images so why do I still get errors about Insufficient Priviledges?

    This is because only real-time customers can view images from the previous two weeks. You will need to contact NASA to gain real-time authorisation. See our documentation for more details.

  3. Why is the image just stripes?

    This is because from 2005 onwards the SeaWiFS data is encrypted. We no longer have a real-time decryption license due to the high costs involved. However we are still receiving the data with the hope that it may be decrypted and useful in the future as a time-series for research use. If you feel the data could be useful to you then please contact us.

Spectral Bands

The SeaWiFS sensor records the following bands. See also the comparison with MODIS and AVHRR

Band Wavelength Bandwidth Colour Measurement
1 412 nm 20 nm Violet Dissolved organic matter (violet absorption)
2 443 nm 20 nm Blue Chlorophyll (blue absorption)
3 490 nm 20 nm Blue / green Chlorophyll (blue / green absorption)
4 510 nm 20 nm Green Chlorophyll (green absorption)
5 555 nm 20 nm Green / yellow Chlorophyll (green reflection)
6 670 nm 20 nm Red Atmospheric aerosols
7 765 nm 40 nm Near infra-red Atmospheric aerosols
8 865 nm 40 nm Near infra-red Atmospheric aerosols


Home Page Dundee Satellite Receiving Station Home Page      Send Us A Comment Send Us A Comment