Near Realtime Data: OVERVIEW
Welcome to the GES DISC Near Real-time (NRT) Data homepage
AIRS and MLS NRT data are elements of the Land, Atmosphere Near real-time Capability for EOS (LANCE). More information on LANCE is available at earthdata.nasa.gov/lance.
We currently offer the following data products and services:
AIRS NRT data products are currently available for Level-1B and Level-2, and are especially useful for users whose primary interest is the low latency for data availability. While standard data products are available within 3 days of observation, NRT data are usually available within 3 hours of observation. All NRT products are generated on a best effort basis. If the input to NRT data processing is delayed by more than 24 hours, the NRT products will not be produced. A description of the differences between the NRT and routine processing can be found here: Difference between AIRS NRT and Standard Products. The main AIRS documentation page has more information about the algorithms: http://disc.sci.gsfc.nasa.gov/AIRS/documentation.
AIRS NRT Imagery
- AIRS NRT images for CO concentration, precipitation estimate, SO2 indicator based on brightness temperature difference, and RGB false-color visible (ascending only) are available via Web Map Service (WMS). This is a rolling WMS archive that offers the most recent 6 days of RGB, and 2 days of CO and SO2. The RGB maps are produced on a 3-km grid, the CO and precipitation estimate are on a 30-km, and the SO2 indicator on 10-km grid. The current-day maps are updated immediately upon new NRT data arrival.
- WMS MapViewer - user-friendly portal for interactive previews of aforementioned AIRS NRT imagery.
- AIRS RGB and Tb (K) at 11 um daily global browse. This browse is produced using the NRT stream. It is at 0.25 deg resolution, and is complete (long-term) for the 2004-present period. Simple UTC-day definition is used, in contrast with the standard grid product.
AIRS NRT Data from OPeNDAP server
AIRS NRT data are originally in a format identical to the regular production - HDF-EOS2 and HDF4, and can be downloaded from an authenticated ftp server. However, AIRS NRT data have been recently served through OPeNDAP server as well, that can provide rudimentary parameter and pixel subset, as well as data format conversion to ASCII and binary. (Read more).
MLS NRT Level-2 temperature and ozone data products are currently available from the GES DISC. The MLS NRT algorithm uses a simplified fast linearized forward model to meet data latency requirements and are therefore not as accurate as the retrievals that constitute the standard MLS products. Nevertheless the results are scientifically useful in selected regions of the earth's atmosphere. The NRT data are typically available within 3 hours of observation and are broken into files containing about 15 minutes of data. The 10 most recent days of MLS NRT data are kept online for users to download. After this users should download the standard Level-2 temperature and ozone data products.
Users are advised to read the most recent MLS NRT User Guide as well as the MLS Data Quality document before using these data. Additional information about MLS can be found on the documentation page: http://disc.sci.gsfc.nasa.gov/Aura/additional/documentation/.