28 January 2016

ERA5 compared to ERA-Interim

The RDA anticipates downloading and processing a significant portion of ECMWF ERA5 beginning calendar year 2016. In response to user inquiries about the characteristics of ERA5, the following basic information from various sources has been tabulated:

Preliminary Comparison of ECMWF ERA-Interim and ERA-5 Reanalyses
Based on Core-Climax Workshop, Brussels, January 15-16, 2015,  and  "ECMWF – Computing and Forecast System", iCAS 2015, Annecy, France, September 2015 (Isabella Weger)
Start of ProductionAugust 2006
IFS1 Cy31r2
June 2015
IFS1 Cy41r1
Model InputAs in operations
(inconsistent SST)
Appropriate for Climate
(CMIP52, HadISST.23)
Model Horizontal GridReduced Gaussian and spectral coefficientsReduced Gaussian and spectral coefficients
Model Horizontal ResolutionNominally 79 km global (0.703125°)
ECMWF T255 N128 (∼512 x 256)
Nominally 31 km global (0.140625°)
ECMWF T1279 N640 (∼2560 x 1280)
Model Vertical Resolution60 levels to 10 Pa (hybrid coordinate)137 levels to 1 Pa (hybrid coordinate)
Time Period1979 to present time1979 to present time
Possible extension back to ∼1950
DisseminationMonthly (up to 3 month lag at NCAR)Monthly (up to 3 month lag at NCAR)
Daily for ERA-5T
ObservationsPrimarily ERA-40, GTS4Various reprocessed CDR5s
Radiative TransferRTTOV67RTTOV611
Analysis Method4D-Var7
1D + 4D-Var for rain
10-member ensemble 4D-VAR (EDA8)
All-sky microwave
Variational Bias CorrectionSatellite radiancesSatellite radiances, ozone, aircraft, surface pressure, radiosondes
Maximum Volume50 TB1.5 PB
1IFS, Integrated Forecast System
2CMIP5, Coupled Model Intercomparison Project Phase 5
3HadISST.2, Hadley Centre Sea Ice and Sea Surface Temperature data set version 2
4GTS, Global Telecommunication System
5CDR, Climate Data Record
6RTTOV, Radiative Transfer for TOVS, TOVS being TIROS Operational Vertical Sounder
 (originally hosting the Microvave Sounding Unit – MSU, the High Resolution Infrared Radiation Sounder – HIRS, and the Stratospheric Sounding Unit – SSU)
74D-Var, 4-Dimensional Variational Data Assimilation
8EDA, Ensemble Data Assimilation

22 January 2016

The data starts here 2

Professor Catherine D'Ignazio asked What would feminist data visualization look like? I've never thought about data visualization and feminism together before, but her essay over at the MIT Center for Civic Media is well worth a read.  So are all the essays from the recent Responsible Data Forum's event about Data Visualization.

Her concept of feminist data visualization is just plain sound data visualization (dataviz).
  1. Invent new ways to represent uncertainty, outsides, missing data, and flawed methods
  2. Invent new ways to reference the material economy behind the data.
  3. Make dissent possible
How this applies at the RDA

20 January 2016

ds735.0 NCEP GDAS Satellite Data Extended

New and improved, with more satellites!
Visualization of DMSP F17 WV courtesy of REMSS.
A chance encounter with members of the WRF Data Assimilation (WRFDA) team led me down a rabbit hole to improve the usefulness of ds735.0 for users of WRFDA.

In 2009, RDA began archiving satellite data products that were ingested into GDAS.  (We backfilled the data to 2004 or 2005.)  Since then, the number and types of satellite data products ingested into GDAS has grown.  It was time for ds735.0 to keep up.

15 January 2016

WRF-able data sets

RDA data specialists has been working with wrfhelp to help Weather Research and Forecasting Model (WRF) users more easily get set up and running with RDA-supplied data sets.

Gridded data in GRIB format is used in the WRF Preprocessing System (WPS) to create both initial conditions inside the WRF domains and lateral boundary conditions outside of them.  In order to read in the GRIB data and write it out into a WRF input file, users need to supply a Vtable--a Rosetta stone of sorts that tells WPS which variables to pull-out from the GRIB file.

04 January 2016

AGU Poster Session Basics

I enjoyed meeting many RDA data users at the 2015 American Geophysical Union Fall Meeting, including two graduate students from IIT Delhi.

The AGU Fall Meeting is always a bit of a homecoming for me as I catch up with colleagues and school friends. (I attended both high school and college within 20 miles of Moscone Center so it is literally a homecoming as well.)

With over 24,000 attendees over the five days of the meeting, it is not logistically possible to give everyone an oral presentation slot.  Moreover,  many find condensing their work into a 12-minute talk difficult.

Most attendees will be offered a spot in a poster session, which allows ample time for face-to-face (f2f) discussion.  Many find the f2f discussion so helpful, they present their work twice in oral AND poster sessions.  I've often seen professors give oral talks and refer the audience to the poster(s) of the graduate student(s) for more details about the work in the talk.

If you haven't attended an AGU before, the AGU Poster Presenter Guidelines are a good place to start.  But, they don't adequately give you a feel for what these sessions are like.