Newsgroups: bit.listserv.biosph-l
Date:         Wed, 7 Oct 1992 13:21:50 GMT
Reply-To:     Terence Sommerville <TSOMMER@IRLEARN.UCD.IE>
From:         Terence Sommerville <TSOMMER@IRLEARN.UCD.IE>
Subject:      Re: Shutdown of Env Satellites

I wish to draw attention to the very valuable and critical work that the
environmental satellites mentioned in an earlier posting, and concerning
the shutting down of them from Oct 2.

The satellites mentioned were : Nimbus -7
                                Erbs
                                Noaa - 9
                                Noaa - 10

It is pure madness that these satellites are being switched off. It inclines
one to think that (probably worongly) there is a conspiracey in the top
etchlons of power to have them turned off.
 It would appear to be the only valid reason as the data from these satellites
have brought forward much news and importantly the 'hard' numbers on the levels
of ozone destruction and global deforestation. Obviously the admin does not
like all these gloomly facts and figures that if we can't see them then these
problems will go away or at least, the real reaons maybe, then can be: 'So Ok'
- , give us some real facts/numbers for destruction of ozone or whatever else
it might be. But of course with the satellites turned off, there will be no
data. Also valuable time series of data extending over a decade of more will
be broken which is disasterous for long term studies and monitoring of trends.

The Nimbus -7 satellites has the TOMS ozone mapper, which allowed the world
to discover the true extent of the Anarctic Ozone Hole. Without it we would
not have the Montreal Agreements as the patchy ground data is too sparse and
the extent of the hole would never have been determined or belived from such
small and limited ground data-sets. Also this satellite in its early days
and still now has instruments for monitoring the Earth Radiation Balance
and the Solar constant. The satellite also pointed out shortcomings in early
ground reflectance models.

Erbs: This satellite does valuable work gathering data for the long term
  observations needed for the Earth Radiation Balance. It is vital for
  validating current climate models in this area and already has had many
  success. Again it would be mad to shut it off. Also it apparently costs
  comparitvely very little to keep on. I should add that the satellite also
  has yielded data on the reflectance values for clouds over the Earth,
  which have provided data that was quite new in that values observed
  were a bit different from that expected.


Noaa 9+10 : These two polar orbiting satellites both take snapshots of the
  whole globe  twice a day each, (at the same local time). That is they
  give strips of overlapping observations that cover the Earth 2 a day.
  They also store on board, for dumpping to the base ground station data
  at 10km resolution for the whole Earth, while regional receiving centres
  can get data at 1km resolution.

  Besides the global coverage, and not just their use for day to day weather
  observations they have provided much long term climatic data.

  These satellites also have microwave sensors which are par of a long term
study measuring ice thickness in the Arctic and Anarctic Seas. Without such
baseline data, you know nothing.

The Very High Resolution Radiometer has done marthon work for determining
Sea Surface temperatures over much of the global and is part of a long term
data set of a decade. The vegative index of the planet and orginally for
Africa was derived from the Infra-red and visible channels on this sensor.
It has allowed for the first time estimates of the actual global mass of
the bio-mass on land, and thus it's role in the carbon cycle. There is so
much that has been learnt from these satellites a giga-byte of text here
would still not cover it all.
(The VHRR has visible and infra-red detectors)

So again I stress that it is crazy that these satellites are being turned
off.

Mention was also made of the UARS - upper atmospheric research satellite,
that it might go after 18 months. This satellite is testing new types of
instruments that are giving info never dreamed of, and it is imperative
that the thing is kept going till the last sensor is worn out.

-Terry.
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