ENVISAT - MERIS - Medium Resolution Imaging Spectrometer (on ENVISAT Satellite, European Space Agancy)
 



envisat


Envisat was successfully launched on 1 March 2002!

MERIS is a medium resolution imaging instrument to be carried aboard the ESA's Envisate satellite. The Envisat satellite is scheduled to be launched in November 2001.

The primary mission of MERIS is primarily dedicated to ocean and coastal sea water colour observations. Knowledge of the sea colour can be converted into a measurement of chlorophyll pigment concentration, suspended sediment concentration and of aerosol loads over the marine domain. The instrument can also be used for atmospheric and land surface related studies.

The global mission of MERIS will have a major contribution to scientific projects which seek to understand the role of the oceans and ocean productivity in the climate system through observations of water colour and will further our ability to forecast change through models. Secondary objectives of the MERIS mission will be directed to the understanding of atmospheric parameters associated with clouds, water vapour and aerosols in addition to land surface parameters, in particular vegetation processes.

MERIS will have a high spectral and radiometric resolution and a dual spatial resolution (1200m and 300m), within a global mission covering open ocean and coastal zone waters and a regional mission covering land surfaces.

MERIS Spectral Bands

MDS 

Nr. 

Band centre 

(nm) 

Bandwidth 

(nm) 

Potential Applications 

1

412.5 

10 

Yellow substance, turbidity 

2

442.5 

10 

Chlorophyll absorption maximum 

3

490 

10 

Chlorophyll, other pigments 

4

510 

10 

Turbidity, suspended sediment, red tides 

5

560 

10 

Chlorophyll reference, suspended sediment 

6

620 

10 

Suspended sediment 

7

665 

10 

Chlorophyll absorption 

8

681.25 

7.5 

Chlorophyll fluorescence 

9

705 

10 

Atmospheric correction, red edge 

10

753.75 

7.5 

Oxygen absorption reference 

11

760

2.5 

Oxygen absorption R-branch 

12

775 

15 

Aerosols, vegetation 

13

865 

20 

Aerosols corrections over ocean 

14

890 

10 

Water vapour absorption reference 

15

900 

10 

Water vapour absorption, vegetation 

MERIS is designed to acquire 15 spectral bands in the 390 - 1040 nm range. One of the most outstanding features of MERIS is the programmability of its spectral bands in their width and position, in accordance with the priorities of the mission.

The above table has been derived for oceanographic and interdisciplinary applications. The exact position of the MERIS spectral bands will be determined following a detailed spectral characterization of the instrument. The spectral range is restricted to the visible near-infrared part of the spectrum between 390 and 1040 nm. The spectral bandwidth is variable between 1.25 and 30 nm depending on the width of a spectral feature to be observed and the amount of energy needed in a band to perform an adequate observation. Over open ocean an average bandwidth of 10 nm is required for the bands located in the visible part of the spectrum. Driven by the need to resolve spectral features of the Oxygen absorption band occurring at 760 nm a minimum spectral bandwidth of 2.5 nm is required.



Link to:
Envisat Web Page (http://envisat.esa.int/) from the European Space Agency (ESA)
MERIS Instrument Web Page (http://envisat.esa.int/instruments/meris/index.html)

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Copyright CRISP, 2001