To assist in your cruise planning, we can
inform you of when the various operational
ocean color sensors will be viewing given
latitude/longitude locations on particular
dates or within a range of dates. Currently,
the sensors include: MODIS,
OCI, OCM, OSMI & MERIS.
Uncertainty in the predicted satellite ephemeris
is thought to be approximately 30 seconds
in equator crossing time when predicted one
month in advance, which translates to approximately
200 km uncertainty in satellite location
at the times given. The uncertainty decreases
with shorter prediction intervals, of course.
Your predictions will be sent to you via email. To provide services to you in a timely manner, we need to obtain your cruise schedule as soon as possible (you may update your cruise information with us later if necessary). Please use our On-line form.
Two versions of the MODIS instrument are in operation. One aboard the Terra satellite (~10:30am equatorial crossing time, descending node), and one aboard the Aqua satellite (~1:30pm equatorial crossing time, ascending node).
The MODIS side-to-side scan angle is +/-
55 degrees. The instrument is nadir pointing.
Predictions generated for MODIS are optimized
for ocean color, therefore by default do not include
times when the sensor would view a location
on the dark side of the earth. Night time predictions are available, just
add a note in the comments section when making the request.
See http://modis.gsfc.nasa.gov/ for a more complete description of the MODIS
sensor.
The MERIS Field-of-view is 68.5 degrees. The instrument is nadir pointing. See http://envisat.esa.int/ for a more complete description of the MERIS sensor.
The MOS-B field of view is nominally .094 degrees, and its side-to-side scan angle is +/- 7 degrees. See the MOS home page http://www.ba.dlr.de/NE-WS/ws5/index_mos.html for a more complete description of the MOS-B sensor.
The OCI field of view is nominally 60 degrees. See the OCI home page http://www.oci.ntou.edu.tw/ for a more complete description of the OCI sensor.
The KOMPSAT-1 OSMI is designed to provide worldwide ocean color data from a 685km sun synchronous orbit. The orbit crossing time is 10:50 AM and the inclination is 98.13 degrees. The OSMI instrument performs whisky-broom scan imaging operation with a cross-track ground swath of 800 km. The ground track re-visit time is 28 days. The field of view is nominally 17 degrees, the side-to-side scan angle is +/- 29.75 degrees. The OSMI instrument is designed to perform imaging operation for 20% per orbit. See the KOMPSAT-1 homepage http://kompsat.kari.re.kr/english/index.asp for a more complete description of the OSMI sensor.
The OCM field of view is +/- 43 degrees. It has a swath width of 1420 km. See the IRS-P4 home page for a more complete description of the OCM sensor. The OCM sensor has the capability to tilt +/- 20 degrees in 5 degree increments to avoid sun glint contamination. Since the OBPG project does not have access to the OCM command schedules, we estimate full tilt transition at the subsolar point
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MODIS: Viewing Times
* 1 = tilt in progress; 2 = tilt schedule unknown, estimated tilt
3 = Sat. view ang. > 45 deg; 4 = Possible sunglint
================================================================================
Date Time Lat Lon Sat. Sat. Range Sun Sun Tilt Flags*
(UTC) (DEG) (DEG) Azi. Elev. (km) Azi. Elev.
--------------------------------------------------------------------------------
13 Mar 2000 10:00:11 45.314 12.508 99.02 48.48 915 154.61 36.88 NADIR
14 Mar 2000 10:42:58 45.314 12.508 287.64 66.28 769 167.85 41.31 NADIR
15 Mar 2000 09:47:53 45.314 12.508 96.99 36.99 1092 150.45 38.24 NADIR
15 Mar 2000 11:25:29 45.314 12.508 294.89 27.35 1333 182.26 42.76 NADIR 3
16 Mar 2000 10:30:44 45.314 12.508 289.28 86.00 713 163.84 41.58 NADIR
The range given is the line of sight distance
between the sensor and the ground location,
not the great circle distance between the
sub-satellite point and the ground location.
