Web-based Reanalyses Intercomparison Tools (WRIT)

Product Descriptions

Monthly/Seasonal Plotting Page: 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.

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. Ability to plot and compare climate index time-series such as the PNA or Niño3.4 or upload your own.

Monthly Correlation Plotter: Calculates correlations (and regressions) of the reanalysis and observational dataset with supplied atmospheric/ocean indices or user uploaded time-series. Users can plot correlations at different lead/lags. They can also create vertical cross-section correlation plots.

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.

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.

Vertical Profiles: Allows users to plot different vertical products from reanalyses including skew-T, variable/height, timeXheight, and vertical transects (daily data).

WRIT Hovmollers: Allows users to make plots of daily and subdaily time by latitude or time by longitude for different reanalysis datasets. Statistics include means and anomalies.


  1. Ocean WRIT: preliminary PPT


  • Smith C. A., G. P. Compo and D. K. Hooper (November 2014): Web-Based Reanalysis Intercomparison Tools (WRIT) for Analysis and Comparison of Reanalyses and Other Datasets. Bull. Am. Meteorol. Soc., 95 (11), 1671-1678. doi:10.1175/BAMS-D-13-00192.1

Future Products

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

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


  • Reanalyses.org: A wiki for advancing reanalyses. Users can find information about reanalyses (atmosphere, ocean, land), how to access and plot data, reanalyses observations, diagnostics, and more. Members can post information and ask questions of the reanalysis community.
  • Caveats. Also see specific tool information.
  • Smith C. A., G. P. Compo and D. K. Hooper (November 2014): Web-Based Reanalysis Intercomparison Tools (WRIT) for Analysis and Comparison of Reanalyses and Other Datasets. Bull. Am. Meteorol. Soc., 95 (11), 1671-1678. doi:10.1175/BAMS-D-13-00192.1


There are two types of datasets in the PSL WRIT tools pages. They are reanalysis gridded observational. Each web tool uses different sets of datasets depending on what it is plotting/analyzing, our storage, server and memoiry resources. There is a link from each page to the datasets used. There are also climate and ocean timeseries available for the correlation webpage and the time-series page. See Users are welcome to suggest new climate indic time-series or gridded observational datasets and we will consider adding them


20CR plot example
WRIT: Composites Plot
20CR plot example
WRIT: Time-series Plot
20CR plot example
Trajectory Plot
2CR plot example
WRIT: Correlation Plot
20CR plot example
Vertical Profiles Plot
2CR plot example
Hovmollers Plot

Referencing WRIT Products

You can use the plots produced from this page in publications. We ask that you acknowledge the Physical Science Division in the publication. For example,
"Image provided by the NOAA/ESRL Physical Sciences Laboratory, Boulder Colorado from their web site at https://psl.noaa.gov/".
You will also need to reference the datasets directly. For references/citations please go to the Reanalyses.org/atmosphere/references wiki page for a current list of reanalysis. For other datasets and time-series, there are links from the WRIT output pages and dataset documentation webpages.

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