NASA Goddard Earth Sciences GES, Data Information Service Center DISC, Distributed Active and Archiv

1
AIRS Data Subsetting Service at the Goddard Earth
Sciences - GES - DISC/DAAC
Gilberto Vicente, Jianchun Qin (JCQ), Jason Li,
Irina Gerasimov, Andrey Savtchenko
http//disc.gsfc.nasa.gov
NASA Goddard Earth Sciences (GES), Data
Information Service Center (DISC), Distributed
Active and Archive Center (DAAC), Greenbelt, MD -
USA

• S u m m a r y
• This poster describes the web-enabled subsetting
  services currently available at the GES DISC/DAAC
  that provide functions for all the Level 1B and
  Level 2 data products from the AIRS/AMSU/HSB
  instruments. The on-line services allow users to
  access the data in interoperable, personalized,
  real-time, on-demand and on-the-fly manners. The
  input file can be subsetted by channels only, by
  parameters only or by channels and parameters.
• The GES DISC subsetting web-based systems are
• On-Demand Subset system - ODS
• Places orders to the long term tape archive,
  where all data for the missions durations are
  kept. Users receive email notification when the
  subset data are ready for pick-up or have been
  pushed to the User's host.
• On-the-fly system OTF
• Works with the GES DISC Data Pool only. It is a
  disk cache of 50 TB of rolling archive, where the
  data are available for instant download. All data
  have certain retention time and are replaced with
  new one as soon as the retention time expires.
• The fine resolution data holdings expire in just
  several weeks because of the large data volumes
  and the limited disk space. Many coarser
  resolution data, like AMSU radiances and the
  upcoming Level-3 products, will be kept for more
  than one year before being replaced. The
  advantage of this subset service is that it is
  instantaneous, and the only wait time is that of
  the data download.
• Three major types of AIRS data subsets are
  available
• Level 1B Channel/Variable subset
• OTF for Infrared geolocated and calibrated
  radiances OTF for Visible/Near Infrared
  geolocated and calibrated radiances OTF for
  AMSU-A1 AMSU-A2 combined, geolocated and
  calibrated brightness temperature ODS for
  Infrared geolocated and calibrated radiances
  (coming soon) ODS for Visible/Near Infrared
  geolocated and calibrated radiances (coming
  soon) ODS for AMSU-A1 AMSU-A2 combined,
  geolocated and calibrated brightness temperature
  (coming soon)
• 2. AIRS Level 2 Parameter subset
• OTF for Standard final retrieval product in 28
  standard pressure levels OTF for Cloud-Cleared
  IR radiances
• ODS for Standard final retrieval product in 28
  standard pressure levels (coming soon) ODS for
  Cloud-Cleared IR radiances (coming soon)

Channels Available for Subsetting
Services Users can either specify any channel
for the subsetting request or choose a
pre-defined set as shown in the table below
(Courtesy of Evan Manning, NASA/JPL). This will
make it easier for selecting all channels in
various frequency ranges.
Algorithm of on-the-fly Subsetting The core
functionality of the HDF-EOS Web-Based Subsetter
(HEW), which is developed by the University of
Alabama in Huntsville (UAH), has been extracted
into a stand-alone callable function known as the
HDF-EOS Subsetting Engine (HSE). The AIRS
Level-1B and Level-2 subsetter makes use of HSE
and can be incorporated into any application that
needs to perform HDF-EOS subsetting. The
subsetter populates a subsetting criteria data
structure which contains the information the HSE
needs to operate. This data structure is passed
to the HSE which then uses the information to
locate and subset the input files into the output
files. The output files are then deliver to end
user via FTP.
Internet
F T P
Overview of GES DAAC Services and Tools
Functionality
Web Logic
HSE Subsetter
DataPool (Online Disk Cache)
Clients Browser
DISC-DAAC Subsetting Service
Parameters Available for Subsetting Services