What are the differences between the two SMAP Near-Real-Time archives?
The NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) provides access to two SMAP LANCE Near Real Time data sets:
- Near Real-time SMAP L1B Radiometer Half-Orbit Time-Ordered Brightness Temperatures, Version 105
- Near Real-time SMAP L2 Radiometer Half-Orbit 36 km EASE-Grid Soil Moisture, Version 107
The data can be accessed from two redundant data archive locations to provide consistent access in the event one archive location is unavailable for maintenance or a system outage. Each archive has an HTTPS data access option, NASA LANCE HTTPS File System and the HTTPS File System, but there are different capabilities available for each archive. Here, we describe the differences between these archives to help you choose the one that best suits your needs.
NASA LANCE HTTPS File System
The NASA LANCE HTTPS File System (SPL1BTB_NRT and SPL2SMP_NRT) provides direct download to the data files through a browser or command line tools. If you need regular and timely access to the NRT data, this archive should be your primary archive because it is not subject to weekly maintenance downtimes. If you need to filter files spatially or temporally, you will need write a download script or include regular expressions with command line tools. For information on how to use command line tools such as Wget or Curl to download from this archive programmatically, see this document: https://nsidc.org/data/user-resources/help-center/programmatic-access-guide-data-daacdataapps
HTTPS File System
The HTTPs file system archive (SPL1BTB_NRT and SPL2SMP_NRT) also provides direct download of the data through a browser or command line tools. This archive can also be accessed through Earthdata Search and the Data Access Tool, which provides additional options to temporally and spatially filter data files, along with scripts and tools to assist in downloading the data. This archive is subject to a weekly maintenance downtime (typically Wednesdays from 9:00 a.m. to 3:00 p.m. U.S. Mountain time). For information on how to use command line tools such as Wget or Curl to download from this archive programmatically, see this document: https://nsidc.org/data/user-resources/help-center/programmatic-data-access-guide