How to use this page

This page enables users to generate an average and its standard deviation, median, and distribution function of any parameter, for any time period and, if desired, for a limited range of values for that parameter and/or for limited range(s) of values of any other parameter(s).

Specify which parameter is to be analyzed by clicking on the left side. Specify a numeric range of this parameter and/or any other parameter(s) in the boxes to the right. Specify the bin width in units natural to the parameter being analyzed in the box below the listing of available parameters.

When a range is not specified for the parameter being analyzed, the program finds the minimum and maximum values of the parameter, and builds bins starting at the minimum value found, of the width specified, until the largest value found is accommodated in the last bin.

The initial output shows the number of points satisfying the criteria, the mean value and standard deviation, the median, and a plot of the distribution function. This output offers the option to see a numeric listing of the distribution function.

The default distribution function appears as point counts in the relevant bins. To display the percentages of counts in bins (rather than counts themselves), use the "DF units" box near the bottom of the interface page to specify "percentages."

For users simply desiring means and standard deviations (also minimum and maximum values), and not distribution functions, specify zero (0) in the "Select bin size ..." box.

After initially creating this page, we added the ability (for low resolution OMNI only) to also filter on day-of-year so that seasonal or Earth-orbit dependencies may be sought by multi-year analyses. (Thanks to M. Collier, GSFC, for pointing out the ~7% seasonal effect in solar wind densities one might expect from the ~3.4% difference between Earth's apohelion and perihelion distances).

If you have any questions/comments about this service contact: Dr. Natalia Papitashvili, Space Physics Data Facility Mail Code 672, NASA/Goddard Space Flight Center, Greenbelt, MD 20771

NASA Official: Robert Candey (, Head of the Space Physics Data Facility