In order to help ensure that this set of tools remain available, we would greatly appreciate feedback on its use, particularly in the classroom, for presentations or for research. Mail to Cathy Smith at (

Background Information
Related Plot/Analysis Tools

Web-based Reanalyses Intercomparison Tools (WRIT)

PSD has created a set of web-based reanalyses comparison tools. We have a monthly/seasonal plotting page that allows users to make maps and vertical cross-sections from various reanalyses. Statistics include means, anomalies and climatologies. Users can also difference the various reanalyses for all three types of statistics (for any overlapping date in the reanalyses). Composites (averaging multiple dates) are also available. We plan to add the ability to use our available climate timeseries (e.g. PNA) or your own time series to composite on.

A monthly timeseries extractor/analyzer extracts timeseries at specified lat/lon or lat/lon ranges and either plots the time-series, time-series differences, and scatter plots. Various statistics are returned in addition to numeric values of the time-series plotted.

A trajectory generator allows users to plot forward and backward air trajectories from different reanalyses (currently NCEP R1, NCEP R2, and 20CR, and ERA-Interim). Users can plot the trajectories of one or more levels on a single plot. The output is plotted on a map and is available as netCDF and as KMZ files suitable for Google Earth.

A distribution analyzer allows users to plot and compare the distributions of daily data during a season from different sources including different reanalyses (currently NCEP R1 and 20CR) and observed data. Users can see where data values have fallen historically and can see how different distribution assumptions impact the tails of the distribution.

Current Web Tools

Future Products

We are exploring the feasibility of various tools. The features we hope to have are:

  • Daily time scale composites
  • Sub-Daily composites
  • Temporal correlations of variables with index time series
  • Spatial correlation comparing different reanalyses
  • Creation and comparison of index timeseries such as the PNA from the various reanalyses

Comments and suggestions for the page can be added to the WRIT page or emailed to the ESRL/PSD webmaster.

WRIT is supported in part by NOAA/ESRL Physical Sciences Division, the NOAA Climate Program Office, and the US Department of Energy's Office of Science (BER)