Mapping floodwater extent for active floods is critical for local and regional officials and for disaster relief organizations that need to ascertain where to focus their efforts. NASA's Land, Atmosphere Near real-time Capability for Earth observation (LANCE) provides data to the Dartmouth Flood Observatory. Learn more about LANCE's MODIS NRT Global Flood Product.
Users can visualize imagery related to floods in Worldview, or download data using the links below.
| Product: Instrument, Platform and Download Link | Description | Browse imagery in Worldview |
MODIS (Terra and Aqua) | MODIS/Aqua+Terra Global Flood Product L3 NRT 250m The flood product has 3 compositing periods (1-day, 2-day, and 3-day) because the best product for a given flood event depends on four unpredictable factors: the specific area of interest; cloud cover; spatial extent of likely flood water; and likely duration of flooding. It is recommend that the user view both the 2 and 3 day products unless latency is a primary concern. Ultimately determining which product provides the best information for a particular event of interest will be up to the user. Product generation consists of three key steps:
The compositing step helps limit false-positives. For more information please see the MODIS NRT Global Flood Product User Guide. | Flood (2-Day Window) and Flood (3-Day Window) |
MODIS (Terra and Aqua) | MODIS/Aqua+Terra Global Flood Product L3 NRT 250m 1-day CS GeoTIFF | |
MODIS (Terra and Aqua) | MODIS/Aqua+Terra Global Flood Product L3 NRT 250m 1-day GeoTIFF | |
MODIS (Terra and Aqua) | MODIS/Aqua+Terra Global Flood Product L3 NRT 250m 2-day GeoTIFF | |
MODIS (Terra and Aqua) | MODIS/Aqua+Terra Global Flood Product L3 NRT 250m 3-day GeoTIFF | |
ATLAS (ICESat-2) | ATLAS/ICESat-2 L3A Along Track Inland Surface Water Data Quick Look ATL13 contains along-track surface water products for inland water bodies. Inland water bodies include lakes, reservoirs, rivers, bays, estuaries and a 7km near-shore buffer. Principal data products include the along-track water surface height and standard deviation, subsurface signal (532 nm) attenuation, significant wave height, wind speed, and coarse depth to bottom topography (where data permit). |
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).
More:
Information on MODIS Corrected Reflectance Imagery layers including
Information on VIIRS Corrected Reflectance Imagery layers including
Browse Corrected Reflectance imagery in Worldview
For more on the difference between Corrected Reflectance and Surface Reflectance Imagery
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
| 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:
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| 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 |
The AIRS Precipitation Estimate Day/Night layer is an estimate of daily precipitation measured in millimeters (mm) using cloud-related parameters of cloud-top pressure, fractional cloud cover, and cloud-layer relative humidity.
The precipitation algorithm is a regression between these parameters and some observed precipitation data. It is an estimate from AIRS using a TOVS-like algorithm and is intended for merging into the precipitation product of the Global Precipitation Climatology Project (GPCP).
Integrated Multi-satellitE Retrievals for GPM (IMERG) is another NRT precipitation product that users may find useful. it is not listed in the table below as it is not a LANCE product (and does not meet the LANCE latency requirement) but it is visible in Worldview.
| Product: Instrument, Platform and Download Link | Description | Browse imagery in Worldview |
AIRS (Aqua) | AIRS Precipitation Estimate The AIRS Precipitation Estimate (AIRG2SSD) layer is a is a variable of the AIRS Level 2 Near Real Time Support Retrieval (AIRS) (AIR2SUP_NRT). The imagery resolution is 2 km and sensor resolution is 45 km. The temporal resolution is daily. References: GES DISC: Aqua/AIRS L2 Near Real Time (NRT) Support Retrieval (AIRS-only) V7.0 (AIRS2SUP_NRT); GES DISC - Near Real-Time Data | AIRS Precipitation Estimate |
| Product: Instrument, Platform and Download Link | Description | Browse imagery in Worldview |
AMSR2 (GCOM-W1) | AMSR-U2 Soil Moisture Normalized Polarization Difference (Day | Night) The AMSR-U2 Soil Moisture Single Channel Algorithm layer indicates the amount of soil moisture over land masses in grams per cubic centimeters (g/cm3). AMSR-U2 Soil Moisture Single Channel Algorithm (Day | Night) The AMSR-U2 Soil Moisture Single Channel Algorithm layer indicates the amount of soil moisture over land masses in grams per cubic centimeters (g/cm3). Both layers were constructed by using the Single Channel Algorithm (SCA) using resampled brightness temperature data. The AMSR-E/AMSR2 Unified Level-2B land product provides a long-term data record by combining AMSR-E and AMSR2 data. The imagery resolution is 25 kilometers, and the temporal resolution is daily. NRT AMSR2 Unified L2B Half-Orbit 25 km EASE-Grid Surface Soil Moisture Beta V2 | AMSR-U2 Soil Moisture: Normalized Polarization Difference (Day | Night) and Soil Moisture Single Channel Algorithm (Day| Night) |
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: Instrument, Platform 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 |
The AMSR2 Snow Water Equivalent layer indicates the amount of water that is contained in snowpack in the Northern and Southern Hemispheres measured in millimeters (mm). Another way to think of it is if all the snow were melted instantaneously, it would be the depth of that water. The snow water equivalent layer is useful for assessing the amount of water that is present in the snowpack and can be used to assess surface runoff when the snow melts and to assess water availability for regions in lower elevations. The Advanced Microwave Scanning Radiometer 2 (AMSR2) instrument is a conically scanning passive microwave radiometer sensing microwave radiation at 12 channels and 6 frequencies ranging from 6.9 to 89 GHz aboard the Global Change Observation Mission – Water 1 (GCOM-W1) satellite.
| Product: Instrument, Platform and Download Link | Description | Browse imagery in Worldview |
| AMSR2 (GCOM W-1) A2_DySno_NRT | AMSR2 Snow Water Equivalent This layer is part of the GCOM-W1 AMSR2 Level-3 Snow Water Equivalent (SWE) data set, which contains snow water equivalent (SWE) data and quality assurance flags mapped to the Northern and Southern Hemisphere 25 km Equal-Area Scalable Earth Grids (EASE-Grids). As NRT Tb Level -1R data are received from the Japanese Aerospace Exploration Agency throughout the day, partial daily products are generated and identified with a product maturity code of "P" in the filename. Once all Level-1R inputs are available, the complete daily product contains product maturity code "R" (near Real time) in the filename. Incremental processing makes data available to the user as it is received, rather than at the end of the day. The imagery resolution is 2 km and sensor resolution is 5 km. The temporal resolution is daily (partial NRT files updated throughout the day to a final product). More: LANCE AMSR2 Near Real-Time Snow Products Available. | AMSR2 Snow Water Equivalent |
LANCE imagery can be overlaid with the following data sets from NASA's Socioeconomic Data and Applications Center (SEDAC), which are also available as layers in Worldview: Flood Hazard Frequency and Distribution, Flood Hazard-Mortality Risk and Flood Hazard Economic Risk.
True-color corrected reflectance image of flooding in Central California on January 23, 2023. Overlaid on the image is the Flood 3-day window composite ending on January 23, 2023. Red indicates flooded areas and blue indicates existing surface water. These images are from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard NASA's Terra and Aqua platforms. Visit NASA Worldview to interactively explore this image.
View the Worldview Tour story Assessing Floodwaters to learn more about the Flood product.