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20040327: Sporadic McIDAS GOES-E Coverage

>From:  James Koermer <address@hidden>
>Organization:  Plymouth State
>Keywords:  200403271644.i2RGixrV019166 Unidata-Wisconsin GOES-East composites

Hi Jim,

>With the interesting tropical cyclone (NHC says hurricane) event off the 
>coast of Brazil, I started looking at the McIDAS area file data for the 
>region.  What I discovered was that the South American coverage is very 
>sporadic--it often cuts off where the imagery did prior to the extension 
>of the area. When data are there, we get good imagery of the system, but 
>the South American coverage seems to be missing more often than when it 
>is present. Is there any explanation as to why?

The South American coverage included in the Unidata-Wisconsin (IDD
UNIWISC datastream) composite GOES-East images is governed by the
scanning schedule of GOES-East (currently GOES 12).  There are four
different scans that provide large spatial coverage:

- full disk -- every three hours

- North American scan -- extends to just south of the equator

- North American extended scan -- extends to just north of
  Rio de Janeiro, Brazil

- Southern scan

The UNIWISC GOES-East images represent as complete a coverage as
possible given the GOES-East scans.

Observations:

- the Southern scan is never made if the Northern scan extends only
  to the equator

- the Southern scan is made only during daylight hours even if the
  Northern scan extends south to Rio.  However, Southern scans
  are not necessarily made when the Northern Extended scan are made.

- the Southern scan is never made when there is rapid/super rapid
  scanning over the US

Whenever the Southern scan is available, it is composited with whatever
Northern scan is available at the same (within 30 minutes) time.

There are many of us who would love to see more consistent scanning
over South America.  This desire should be realized as the GOES-R
series of satellites moves into service sometime after 2010.

Tom

>From address@hidden  Sat Mar 27 10:50:50 2004

Tom,

Thanks. It clarifies the timing of the coverage. It looks like they
have increased the frequency of the coverage over the past 8
hours--probably because of the storm.

Jim