MODIS Instrument Characteristics, Performance, and Data for Climate Studies - Satellite-based Applications on Climate Change - page 41

Particulate Organic Carbon
Remote Sensing Reflectance
Sea Surface Temperature (11 um daytime and nightime)
Sea Surface Temperature 4 um (nightime)
One essential aspect involved in the provision of the products from MODIS is the
updating of the data to reflect new knowledge about the performance of the instru-
ment and refinement of the algorithms as they are compared to ground truth and other
information that show what improvements should and can be made. To date (early
2012) several “collections” or versions of the Level-1, land, and atmosphere data
have been accomplished that have significantly improved the products. A “collection
6”/version 6 reprocessing is underway and will be largely completed in 2012. The
ocean products have been reprocessed even more often so as to allow compatible
observations with the SeaWiFS observations and Aqua MODIS observations in
particular. MODIS Terra observations have also been reprocessed repeatedly to
incorporate as much improvement as possible for use in biological oceanography
studies. As noted above, the status of reprocessing for all MODIS products can be
obtained by visiting the sites noted above in the products list.
A few examples of results using the MODIS data record with some key figures
are noted below.
The first example (Fig. 3.8 ) shows the global, mean distribution of aerosol
optical depth for 4 months derived from MODIS Aqua observations extending
from 2002 to the present (2012). This information can be seen along with other
MODIS atmosphere products at http://modis-atmos.gsfc.nasa.gov/products.html .
Another example from Hall et al. ( 2012 ) illustrates the use MODIS snow cover
data over several years to evaluate the variability in depletion curves over several
years on the Wind River Basin, Wyoming (see Fig. 3.9 ).
The third example comes from the processing of MODIS Aqua data for ocean
products. The examples shown in Fig. 3.10 illustrate the annual concentration of
chlorophyll-a concentration over the Aqua MODIS data record extending from
2002 to the present (2012). Several composites can be seen or obtained extending
from daily composites to a composite of the entire mission.
3.4 The MODIS Operational Follow-On Instrument: VIIRS
From the point of view of continuing MODIS-like observations for climate studies,
it is fortunate that the sensor called the Visible and Infrared Imaging Radiometer
Suite (VIIRS) was launched successfully on October 28, 2011, on the Suomi NPP
(National Polar-orbiting Partnership) satellite. The NPP mission is the first of the
NASA/NOAA Joint Polar Satellite System (JPSS). By virtue of the JPSS being an
“operational” system, there is a commitment to fly VIIRS on missions after NPP
and thus obtain observations consistent with MODIS for the foreseeable future.