Normalized Difference Vegetation Index (NDVI) images produced from NASA's Land, Atmosphere Near real-time Capability for Earth observation (LANCE) data are used to monitor vegetation and crop condition. There are several global/regional scale systems in place that report on drought, food shortages and forecasting crop yields including the USGS Famine Early Warning Systems Network (FEWS NET) and Group on Earth Observations (GEO) Global Agricultural Monitoring (GEOGLAM) crop monitor.

Corrected Reflectance Imagery

MODIS and VIIRS Corrected Reflectance imagery are available only as near real-time imagery. The imagery can be visualized in Worldview and Global Imagery Browse Services (GIBS).

Information on MODIS Corrected Reflectance Imagery layers including:

• Corrected Reflectance True Color (Bands 1-4-3),
• Corrected Reflectance (Bands 3-6-7)
• Corrected Reflectance (Bands 7-2-1)

Information on VIIRS Corrected Reflectance Imagery layers including:

• Corrected Reflectance True Color (Bands I1-M4-M3),
• Corrected Reflectance (Bands M3-I3-M11)
• Corrected Reflectance (Bands M11-I2-I1)

Browse Corrected Reflectance imagery in Worldview

For more on the difference between Corrected Reflectance and Surface Reflectance Imagery

Land Surface Reflectance

In comparison with the MODIS Corrected Reflectance product, the MODIS Land Atmospherically Corrected Surface Reflectance product (MOD09) is a more complete atmospheric correction algorithm that includes aerosol correction, and is designed to derive land surface properties.

Product: Instrument, Platform and Download Link	Description	Browse imagery in Worldview
MODIS (Aqua) MYD09 MODIS (Terra) MOD09	doi:10.5067/MODIS/MYD09.NRT.061 (Aqua) and doi:10.5067/MODIS/MOD09.NRT.061 (Terra) More information on MODIS Land Surface Reflectance Products including: MODIS (Aqua/Terra) Land Surface Reflectance True Color (Bands 1-4-3) MODIS (Aqua/Terra) Land Surface Reflectance True Color (Bands 7-2-1) MODIS (Aqua/Terra) Land Surface Reflectance True Color (Bands 1-2-1)	True Color Bands 1-2-1 Bands 7-2-1
VIIRS (Suomi NPP) VNP09_NRT	VIIRS Land Surface Reflectance  The VIIRS Surface Reflectance provides continuity with the EOS-MODIS Land Surface Reflectance product.The Suomi NPP/VIIRS surface reflectance products are estimates of surface reflectance in each of the VIIRS reflective bands I1-I3, M1-M5, M7, M8, M10, and M11. Surface reflectance for each moderate-resolution (750m) or imagery-resolution (375m) pixel is retrieved separately for the Level-2 products and is obtained by adjusting top-of-atmosphere reflectance to compensate for atmospheric effects. Corrections are made for the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. The inputs to the surface reflectance algorithm include top-of-atmosphere reflectance for the VIIRS visible bands (VNP02MOD, VNP02IMG), the VIIRS cloud mask and aerosol product (NPP-CMIP_L2), aerosol optical thickness (NPP_VAOTIP_L2, NPP_VAMIP_L2), and atmospheric data obtained from a reanalysis (surface pressure, atmospheric precipitable water, and ozone concentration). All surface reflectance products are produced for daytime conditions only.	Coming soon

Land Surface Temperature

Land Surface Temperature layer shows the temperature of the land surface in Kelvin (K). This measurement differs from air temperature measurements as it provides the temperature of whatever is on the surface of the earth for example, bare sand in the desert, ice and snow covered area, a leaf covered tree canopy and even the temperature of man-made buildings and roads. Land Surface Temperature is useful for monitoring changes in weather and climate patterns and used in agriculture to allow farmers to evaluate water requirements for wheat, or determine frost damage in orange groves.

Product: Instrument, Platform and Download Link	Description	Browse imagery in Worldview
MODIS (Terra) MOD11_L2 MODIS (Aqua) MYD11_L2	MODIS Land Surface Temperature and Emissivity The MODIS Land Surface Temperature and Emissivity (LST&E) product is available from both Terra and Aqua satellites. The sensor and imagery resolution is 1 km, and the temporal resolution is daily. doi:10.5067/MODIS/MOD11_L2.NRT.061 and doi:10.5067/MODIS/MYD11_L2.NRT.061	Land Surface Temp (Day/Night)
VIIRS (Suomi NPP) VNP21_NRT	VIIRS Land Surface Temperature and Emissivity VIIRS/Suomi NPP Land Surface Temperature and Emissivity 6-Min L2 Swath 750m NRT products doi:10.5067/VIIRS/VNP21_NRT.001	Coming soon.

Snow Cover

The MODIS snow cover layer shows the presence of snow cover over land and water bodies as an index related to the presence of snow. It is based on a Normalized Difference Snow Cover Index (NDSI) that is derived from the cloud free snow reflectance sensed by the MODIS instrument, and hence this layer shows presence of snow during day time and under cloud clear condition only. NDSI snow cover though could be retrieved in the valid range of (0, 1.0) at every pixel, additional tests like surface temperature screening linked with the surface height is used for accurate detection. Snow is precipitation that forms from water vapor in the atmosphere where temperatures are below 0° Celsius. If the ground temperature is also below freezing, snow will accumulate on the ground as bright, white layer of snowpack. Snow cover reflects sunlight back into the atmosphere, helping to cool the Earth’s surface. Snowmelt is used for drinking water, water for crop irrigation, and can moisturize soil to reduce the risk of wildfire in many areas in the world. When snow melts in the spring, too much snow can cause springtime flooding.

Product and Download Link	Description	Browse imagery in Worldview
MODIS (Terra) MOD10_L2 MODIS (Aqua) MYD10_L2	MODIS Snow Cover (Normalized Difference Snow Index (NDSI)) The MODIS Snow Cover layer is available from NASA's Terra and Aqua satellites. The sensor and imagery resolution is 500 m and the temporal resolution is daily. DOI: doi:10.5067/MODIS/MOD10_L2.NRT.061 and doi:10.5067/MODIS/MYD10_L2.NRT.061	Snow Cover

Visualize NRT Data Related to Vegetation in Worldview

Read articles about monitoring vegetation from NASA's Earth Observatory:

• Measuring vegetation
• Earth Matters - Why Caribbean Islands Went Brown And How Long Will They Stay That Way?