31 July 2015

NCEP Climate Forecast System Data: Some New Ways to Get a Subset

The Climate Forecast System Reanalysis (CFSR) was created by the National Centers for Environmental Prediction in 2010 by running their updated Climate Forecast System (CFSv2) retrospectively from January 1, 1979. CFSv2 continues to run operationally to produce NCEP's monthly and seasonal forecasts. You can read about the differences between reanalyses and operational model output here, and you can see a list of all of the reanalysis data hosted by the RDA from our home page, under the "Atmospheric Reanalysis Data" heading.

28 July 2015

The International Surface Pressure Databank version 2: A new publication in the Geoscience Data Journal

The RDA is pleased to announce the publication of the data paper titled "The International Surface Pressure Databank version 2", which was recently published in the Geoscience Data Journal and is available at http://dx.doi.org/10.1002/gdj3.25.  The article provides a full description of version 2 of the International Surface Pressure Databank (ISPDv2), a dataset which is archived in the RDA and can be accessed from the ds132.0 dataset page.

15 July 2015

JRA-55C in the RDA: The Japanese 55-year Reanalysis Using Conventional Data Only

As a subset of the Japanese 55-year Reanalysis (JRA-55) project, the Meteorological Research Institute of the Japan Meteorological Agency has conducted a global atmospheric reanalysis that assimilates only conventional surface and upper air observations, with no use of satellite observations, using the same data assimilation system as the JRA-55. The project, named the JRA-55 Conventional (JRA-55C), aims to produce a more homogeneous dataset over a long period, unaffected by changes in historical satellite observing systems. The dataset is intended to be suitable for studies of climate change or multi-decadal variability. The reanalysis period of JRA-55C is from November 1972 to December 2012. The JMA recommends the use of JRA-55 to extend JRA-55C back to January 1958.

The Data Support Section at NCAR has downloaded all JRA-55C data. The entire archive has been reorganized into single parameter time series, and model resolution data has been transformed to a regular Gaussian grid. The JRA-55C products are currently being made accessible to RDA registered users of JRA-55, and will appear incrementally via the Data Access tab on the dataset homepage(s) JRA-55C: The Japanese 55-year Reanalysis Using Conventional Data Only, and JRA-55C: Monthly Means and Variances.

14 July 2015

GRIB Practical Exercise 1: Data Discovery

If you want to learn more about a specific data format, scroll down to the blue box at the bottom of the NCAR RDA home page and follow the links.  The Format Descriptions link to the encyclopedic WMO documentation for people who need to write interfaces to GRIB data.

Scroll to the bottom of rda.ucar.edu and follow the links to GRIB documentation.

07 July 2015

Where's my data?

The RDA considers the ecosystem that data resides in when deciding what to archive.  For instance, we archive both NCEP GFS and FNL analyses*; they are part of the NCEP Global Data Assimilation System (GDAS) system.
Researchers may want to examine the data assimilated into the analyses.  They could be useful for future reanalyses, Observation System Simulation Experiments (OSSE) or regional monitoring.  Thus, we archive several of the major data sources in the GDAS data flow.  You can see the data shortfall in the AIRS 2015 total web server inventory listing.

06 July 2015

What is GRIB?

"What is GRIB?" is a nontrivial question. There isn't even agreement on whether it stands for GRIdded Binary or General Regularly-distributed Information in Binary form.   This is an idiosyncratic and non-official take on GRIB by an autodidact of met data.

GRIB and BUFR are World Meteorological Organization (WMO) standards for data exchange.  WMO calls them data exchange formats, but many refer to them simply as data formats.  The loss of that one middle word is significant.