RELEASE 4 (V4.10):
The fourth release of the CALIPSO data products includes new versions of its
standard Level 1 and Level 2 lidar data. The V4.10 CALIOP Level 2 data products
are the first major revision to the Level 2 product suite since May 2010. The
extensive improvements made in this new release correct numerous artifacts and
significantly enhance the content and quality of the science data.
The data processing algorithms and code used to generate the updated V4.10
CALIOP Level 1 data product are unchanged from V4.00. The only differences
between the two versions are the essential ancillary data sets. The GTOPO30
Digital Elevation Model (DEM) used in V4.00 has been replaced by a substantially
more accurate DEM developed by the CloudSat project. Likewise, the Global
Modeling and Assimilation Office (GMAO) Forward Processing for Instrument Team
(FP-IT) meteorological forecast product has been replaced with the higher quality
Modern Era Retrospective-Analysis for Research (MERRA-2) reanalysis product.
Use of the MERRA-2 data has been shown to yield more accurate and reliable
CALIOP calibration coefficients.
The version 3.x (3.01, 3.02 and 3.30) CALIOP Level 1 and Level 2 data products
will continue to be generated and made publically available, with version 4.10
running in parallel. Unlike version 3.x, which is released continuously
following 2-3 day latency from downlink, new releases of the version 4.10
Level 1 and Level 2 product will have a latency of several weeks. This change
in latency is a direct response to now using the MERRA-2 meteorological data.
Generation and distribution of the standard version 3.x will continue until
release of an updated version of the IIR Level 2 product, at which point the
standard will no longer be supported. Expedited and quick-look datasets, which
continue to rely on the GMAO FP-IT, will remain at version 3.x.
RELEASE 3 (V3.01, V3.02 and V3.30): The third release of the CALIPSO data products features a comprehensive restructuring and
expansion of the Lidar Level 2 cloud and aerosol profile products; significant enhancements
to the Lidar Level 2 cloud and aerosol profile products; and the implementation of an improved
calibration technique for the Lidar Level 1 532 nm daytime calibration.
The primary contents of the CALIOP Level 1 product are calibrated profiles of 532 nm
perpendicular attenuated backscatter and total attenuated backscatter at 532 nm and 1064 nm.
The version 3 CALIOP Level 1 data are released with a product maturity classification of
Validated Stage 1, indicating that initial validation of the CALIOP attenuated backscatter
products has been successful.
The CALIOP Level 2 products consist of the full resolution vertical feature mask,
cloud and aerosol layer products reported at several different spatial resolutions,
and cloud and aerosol profile products reported at a uniform 5-km horizontal resolution.
Validation of the Level 2 products is an on-going process, and some products are better
characterized than others. Preliminary validation has been accomplished for the layer
detection, cloud-aerosol discrimination, and layer sub-typing algorithms.
Data products derived solely from these algorithms are designated as Validated Stage 1.
Validation of the optical properties algorithms that generate extinction profiles and layer
optical depth estimates is a considerably more challenging task. As a consequence,
while all studies to date indicate acceptable performance, the status of those data
products derived from this second class of algorithms remains Provisional.
All obvious artifacts have been identified and corrected in these data,
but only limited comparisons with independent data sets are currently available.
The science algorithms used to produce the V3.30 CALIOP data products are identical
to those used to generate the V3.01 and V3.02 products; however, some of the ancillary
data used in the V3.30 analyses is different. All CALIOP data products rely on
meteorological data provided by NASA’s Global Modeling and Assimilation Office
(GMAO). The V3.01 and V3.02 data products were produced using the GMAO’s GEOS 5.2
data products. These products have now been phased out of production. Beginning with
V3.30, the CALIOP data products are generated using the new GEOS-5 FP-IT data
stream of near-real-time assimilation products that are produced primarily for
NASA satellite instrument teams. The snow and ice data set used in the V3.01 and
V3.02 products has also been discontinued. The V3.30 CALIOP data products now
use a new snow and ice data provided by the Air Force Weather Authority.
Here are listed brief data quality summaries for the data products from each instrument. Detailed
data quality summaries can be found by following the appropriate links on this page.
The data products are grouped into the following categories:
Uncertainties for specific parameters are reported in the individual quality
statements. Quality designators indicate the maturity of products and
individual parameters, and include "Beta", "Provisional",
"Validated Stage 1", "Validated Stage 2", and
"Validated Stage 3". A data product may contain science data sets (SDSs) at varying
quality levels.
Early release products for users to gain familiarity with data formats and
parameters. Users are strongly cautioned against the indiscriminate use of
these data products as the basis for research findings, journal publications,
and/or presentations.
Provisional:
Limited comparisons with independent sources have been made and obvious
artifacts fixed.
Validated Stage 1:
Uncertainties are estimated from independent measurements at selected
locations and times.
Validated Stage 2:
Uncertainties are estimated from more widely distributed independent
measurements.
Validated Stage 3:
Uncertainties are estimated from independent measurements representing
global conditions.
The tables below provide quality summary information for all of the
CALIPSO data products. Each table contains links to both (a) an Overall
Quality Summary, which provides a file-level quality assessment for each data
product; and (b) a much longer Detailed Quality Document that describes
each scientific data set (SDS) found within the product file, and provides
quality assessments and usage guidance at the SDS level. Please be aware that
earlier generations of the data products may be of different (presumably lower)
quality than current products. It is important, therefore, to note that dates
on quality statements correspond to the dates when the CALIPSO data products
were released, not to the dates when the raw measurements were acquired by the
CALIPSO instrument.
Product Specific Quality Statements
Lidar Level 1B Profiles Half orbit (Night and Day) geolocated, calibrated Lidar Profiles and Viewing
Geometry Products
Lidar Level 3 GEWEX Cloud Monthly A reformatted version of CALIPSO’s contribution to the GEWEX cloud assessment of global cloud datasets from satellites. Three files: day, night, all.
