Getting Started with MODIS V6 Land Surface Temperature Data Part 2
This video focuses on the National Aeronautics and Space Administration’s (NASA) Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Version 6 Land Surface Temperature data distributed by NASA’s Land Processes Distributed Active Archive Center (LP DAAC). Information about the MODIS Version 6 Land Surface Temperature data products, the scale factor of the data and other data values, and using a color map to visualize Land Surface Temperature will be provided in this video. The video will also cover how to find Land Surface Temperature resources on the LP DAAC website. To learn more about on MODIS Version 6 Land Surface Temperature data and other data products distributed by the LP DAAC please visit https://lpdaac.usgs.gov/.
The LP DAAC is one of twelve NASA Earth Observing System Data and Information System (EOSDIS) DAACs. It is located at the United States Geological Survey (USGS) Earth Resources Observation Systems (EROS) Center in Sioux Falls, South Dakota. The LP DAAC ingests, archives, processes and distributes NASA Earth science land processes data and information.
Location Taken: Sioux Falls, SD, US
Video Credits: Content created by Danielle Golon (Contractor to USGS EROS)
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.