Getting Started with MODIS Version 6 Land Surface Temperature Data Part 2:
Using the Data. Presented by the Land Processes Distributed Active Archive
Center or LP DAAC. This is part 2 of the “Getting Started with MODIS
Version 6 Land Surface Temperature Data” video series. This video will
cover the Science Datasets or SDSs in each MODIS Land Surface
Temperature file, the fill values and scale factor for the data and
how to apply it, how to visualize Land Surface Temperature using a
color map, and how to find Land Surface Temperature resources on
the LP DAAC website. The MODIS Land Surface Temperature Version 6
products provide per-pixel land surface temperature or LST in
Kelvin, and emissivity. LST describes the temperature of the
land surface, not the air temperature. Emissivity is the
ratio of thermal infrared energy radiated from an object compared
to that of a blackbody under the same conditions. All of the Land
Surface Temperature products are derived from the initial five minute
level 2 swath products, MOD11_L2 and MYD11_L2. MODIS Land Surface
Temperature products are distributed as Hierarchical Data Format – or HDF
files. The file name contains “MOD11” indicating Terra MODIS
observations or “MYD11” for Aqua MODIS observations. Here is a
visual representation of the data stored within a single Terra MODIS
Version 6 Daily Land Surface Temperature and Emissivity 1
kilometer level 3 gridded product, MOD11A1, HDF file. The HDF file for
this product contains Daytime and Nighttime LST data, quality
information, observation information, emissivity data,
and the clear sky coverage. It is important to know that a
scale factor must be applied to the Land Surface Temperature and
Emissivity data before you begin using the data. A scale factor of
0.02 should be used for Land Surface Temperature data.
For example, if the data value is 15592, multiply by .02 to get
311.84 Kelvin after the scale factor is applied. The emissivity
data have a scale factor of 0.002 and an additional offset of 0.49.
For example, if the data value is 241, multiply by .002 for the scale
factor and then add .49 for the additional offset to get 0.972 or
97.2%. The designated fill value for both the Land Surface
Temperature and Emissivity is zero. Users can apply a scale factor to
their data via a data script recipe, through manual calculation,
or in certain software programs. Some of the other science datasets
in the Land Surface Temperature products have various scale factors,
valid data ranges, and fill values. Please refer to the Digital Object
Identifier or DOI Landing Page for each Land Surface Temperature
product to learn more about specific values for the other science datasets.
Once you have an understanding of these values you can work with and
observe each of the science datasets. Here is a Land Surface Temperature
image centered over the border of Tajikistan, Afghanistan, Pakistan,
India, and China from June 9th to 16th, 2016 shown using the Terra
MODIS 8-Day Land Surface Temperature 1 kilometer level 3 gridded product
MOD11A2. The daytime LST are available as a single science
dataset. A colormap is an RGB assignment of colors to certain
values. A colormap can be added using most Geographic Information
System or GIS software to better visualize the variations in
temperature. Here is the same 8-Day Daytime LST image shown using a
colormap. The LST of the area ranges from hotter, shown in shades of red
and orange, to cooler shown in shades of greens and blues.
The color black is used for fill values and data with no values.
For examples of how MODIS Land Surface Temperature products can
be used in scientific applications, visit the LP DAAC website.
The Publications table has relevant literature, the Data in Action
section has short stories about scientific applications, and the
E-Learning page has tutorials, presentations, and other product resources.
Thank you for watching our video. For more information on MODIS Version 6
Land Surface Temperature data please visit the LP DAAC website
at lpdaac.usgs.gov.