Physical Sciences Division

Various global reanalyses are provided as well as 2 observational datasets. For the MERRA, we are using the lower resolution data (1.5x1.5). MERRA is not defined for values below the surface (details). All other reanalyses datasets we provide have values for the pressure levels below the surface. Some single level variables are also made available.

Select "none" or a second global reanalyses. Differences are calculated by interpolating the lower spatial resolution values to higher, if the datasets aren't at the same resolution. Differences for vertical cross sections are calculated using this set of levels that is common to all the reanalyses we are using: 1000., 850.,700.,600.,500.,400.,300.,250.,200.,150.,100.,70.,50.,30.,10. Cross-section is interpolated from the lower to higher resolution dataset before differences are calculated. For the MERRA, we are using the lower resolution data (1.5x1.5). MERRA is not defined for values below the surface (details). All other reanalyses datasets we provide have values for the pressure levels below the surface.

Monthly data is available for each of the reanalyses for the time period of the reanalysis. Ending dates vary. We plan to keep the datasets as up-to-date as possible. Currently, data is available through at least 2011 for all but MERRA and 20CR (2010) reanalysis datasets. Details on datasets are available.

Mean

Plots are the values from the model or observed dataset.

Long Term Mean (Climatology)

The long term mean of the variable for a specified month is plotted. We use 1981-2010 where possible. Anomaly datasets may have a different climatology.

Anomaly

Plots are of mean minus climatology for the variable. Each monthly anomaly is computed separately.

Map: Latitude by Longitude)
A latitude/longitude plot. Enter longitudes east to west. There are some custom regions provided.

Vertical Cross section: Latitude by Height
A vertical cross section. Plot is averaged over longitudes entered (east to west). Averages are only available for at most 360 degrees. For a plot at one longitude, enter the same value for eastern and western longitude bounds. Page will use nearest latitudes and longitudes to those selected. Latitudes and longitudes available differ. They are usually points (reanalyses) or centers (observed).

Vertical Cross section: Longitude by Height
A vertical cross section. Plot is averaged over latitudes entered (south to north). For a plot at one latitude, enter the same value for southern and northern latitude bounds. Use decimal form of degrees. The plot will use nearest latitudes and longitudes to those selected. Latitudes and longitudes available differ. They are usually points (reanalyses) or centers (observed).

Cylindrical equidistant (latitude/longitude on same scale) or polar stereographic (northern and southern) are available.

You can select either color or black and white for the shading/contours. Contour types are simple contour lines, shade fill or both.

you can increase or decrease the plot size by inputting a percentage between 1 and 200. The default is 100%. Values outside those ranges are ignored.

Select this to draw contour labels on the contours.

A desired contour interval and range can be input instead of the default being used. This enables plots to be compared or generating images that can be animated. The interval (small to large) AND the range must be input. There is a limit of 150 contour levels with this method.

The default is a GIF plot. For maps, a user can choose "google earth". For this, a global map is created and put into kmz/kml format. In addition, for users with google earth browser installed, the map can be viewed in the google map application.

The main interface for this page is an html form. The data that are input into this form are processed by a Perl script. The script reads the inputs, tests for bad inputs and then NCL is run to read, analyze and plot the data. NetCDF and postscript are also produced. For Google Earth, kmz and kml files are also created. The netCDF file, image and other files are kept in a directory in which the files are periodically deleted.

Please let me know if find the page useful. Likewise, let me know if you think any instructions are unclear, if you think there are bugs or if you have any suggestions for improvements of any type. I would particularly like to know if you use these pages for teaching purposes and if so, how. I can be reached by email at cathy.smith@noaa.gov or by phone at (303) 497-6263.

The plots and data generated from the page are provided as a helpful aide to research. While every attempt is made to assure the plots are accurate, users are encouraged to confirm results, particularly if plots are to be used for publications or similar uses. Both plotting and analysis have underlying assumptions that may impact specific results. The page is not guaranteed to be available as PSD is not an operational center. Data may be updated or changed at the source and therefore replaced at our site. Please check dataset documentation for further information. Please send us any questions about the plots or analysis methods.