The 4th WCRP International Conference on Reanalysis is scheduled for May 7-11, 2012, just outside Washington DC, on the Metro Line in Silver Spring MD. At this time, Registration and Abstract submission forms are under development, but should be available soon.
For details on the objectives of the conference and agenda, please visit: http://icr4.org
TRMM TMI rainfall data updated to version seven, which included a format change (starting July 1). MERRA data production was put on hold while the data ingest of version 7 was updated. This was only a short delay. Current tests indicate no anomalous behavior in the time series that can be attributed to this change. June 2011 data should be online within a few days, and July production and distribution should be available by mid-August, back on schedule.
Following the USCLIVAR Reanalysis workshop (Nov 2010, Baltimore MD), a short summary of the proceedings and recommendations was developed. It was published in AGU EOS last week.
The aim of the workshop was to bring together separate disciplines working on data assimilation and reanalysis in separate disciplines, to discuss the needs for and direction to integrated Earth system analysis (IESA). The strengths and weaknesses of the current reanalyses were discussed, as well as potential improvements to each of the major components of reanalyses (model, data assimilation and observations). Despite the current number of reanalyses, they remain in demand, and still have room for improvement, especially in the representation of present climate.
MERRA precipitation (color shaded) with CPC gauge observations (black contour) time averaged for April 2011. (units: mm/day)Recently a question about some regional climate data came in, it needed to be independently checked. It seemed like a good opportunity to make use of the Giovanni portal into the MERRA data. Many of the MERRA data collections are available to Giovanni, even 2D one hourly data. MERRA data is directly linked through the Giovanni page, but also from the MERRA data holdings page, which may be more desirable since there is more documentation about what is in each MERRA collection.
Once at the MERRA/Giovanni page, there are options to choose variable(s), region, level and time. There are several hardwired calculation/visualization options in which the data can be presented. Depending on the size of the request, there may be a few minutes before the results are available. However, once they are there is options to download the visualizations, or the data. Both source data and processed data can be retrieved. At this time, HDF, NetCDF and ASCII formats are supported for download.
The FTP Subset is the best way for large requests, and OpenDAP/GDS still serves a purpose for some on the fly live calculation jobs needing flexibility. However, Giovanni fills the middle ground in data visualization and retrieval. It certainly is worth a test drive, and may be a useful option in many cases. Given the range of what can be done with MERRA data, the wide array of ways to access the data should fit most needs.
Papers are now available at the AMS Online Journals MERRA Special Collection. The MERRA Overview by Rienecker et al. should be considered as the fundamental citation for the MERRA project and data set.
There have been numerous discussions in meetings over the last year or so regarding the multitude of new reanalyses available. These have been generally concerned with users time and effort in deciding which reanalysis best suits any particular users needs. This is mostly true, though some features of reanalyses are equally well represented. The utility of reanalyses is very broad, and has been the key in there continuing development. However, it is nearly impossible for a developing center to sufficiently document all possible features of a reanalysis in reasonable time to provide access to the community. So, there is some effort incurred, for intercomparisons, to be the first researcher on any given topic utilizing all these reanalyses.
It takes time to document a system, but in time we can characterize well the systems. For MERRA, we have produced documentation, the MERRA Atlas, a www page listing the most recent papers (that we know of) and also this blog. However, there is much much more available. How can communicate collective knowledge about all the reanalysis systems? Consider also that communication in this sense is a two-way street. The users of reanalyses have valuable information as well. Complicating matters, we'd like this information with short turnaround time, minimizing duplicative efforts.
While peer review journals provide the formal record, the explosion of internet tools allows for much more rapid transfer of information. Wikipedia has an entry and definition of reanalysis. But the research community has much more demanding needs for knowledge. Given the problem and difficulty of any solution, we can use the internet for documentaiton of not only the developing centers understanding of the various reanalyses, but also the much more vast user community.
So, reanalyses.org has been set up to provide a place for information and research to be posted more quickly than peer review printing (though, early online release that some journals are adopting is a great positive step). This site is intended to be a forum for all aspects of reanalyses and the two way street we need to keep up on the rapid developments. The site is also an experiment, in a way. Consider that it will only grow and thrive with active participation of developing centers, expert researcher and new users! Have a look around reanalyses.org, and if you have some unique comparison or evaluation to share, request an account and add a link or report!
With the holidays, travel and deadlines it has been difficult to put together regular snippets of interesting results. The hope was to summarize the papers coming out but there are quite a few and a lot of useful information. I hope to get back to that in the coming weeks.
In the mean time, it is important to share the information in a timely fashion, and the speed that the internet and electronic publishing permits is much greater now than anytime before. The GMAO is collecting information and manuscripts with permission of the authors on our www site. The MERRA Publications page is growing well, most manuscripts are presently submitted for publication and some already accepted. In addition, while most of the papers are written by GMAO staff, quite a few have been authored outside the GMAO, without a GMAO co-author. Most papers have some critical review of the realism of the system. It is important for the development of the systems to account for the strengths and weaknesses, and is a challenge to improve the system while keeping the processes that are already well represented. Shared knowledge would be critical to this development.
Included on the page is the general overview description of the project: Rienecker, M.M., et al., 2011. MERRA - NASA's Modern-Era Retrospective Analysis for Research and Applications. J. Climate (submitted). Check the page linked above for the latest status on the paper. At this time it is still being reviewed.
