FTPBrowser


This text addresses use of the interfaces accessible from merged.html

For all interfaces, users have a choice of a plot or a listing of the points that would otherwise have been plotted. In all cases, users specify which parameters to plot or list and for what time span.

For the intensity-time profile interface to the IMP/Wind/ACE plasma data, the user must specify pairs (up to 4 thereof) of like parameters and their sources for output. For the other available multi-source data sets, the intensity-time profile interface automatically plots the user-selected parameter(s) from all available sources.

For the scatter plot/regression fit interfaces, the user must specify one pair of like parameters from two sources and which will be Y and which X. The user must also specify whether to determine regression parameters using a "delta-Y" method or a "perpdist" method. These are discussed at http://omniweb.sci.gsfc.nasa.gov/html/scat_des.html

These scatter plot interfaces give users the option to "filter" the points plotted/regressed by values of the points being plotted/regressed and/or by values of any of the other parameters on the interface screen, including the numbers of fine-scale points contributing to the averages and the impact parameters between any spacecraft pair. (See /impact_des.html for a definition of and access to impact parameters.) To use the filtering capability, enter the desired minimum and/or maximum value(s) of the filtering parameter(s) in the boxes immediately below them on the interface.
Note that when filtering a regression of logarithms, the desired minimum and maximum filter values are of logarithms and not of physical parameters Np, T, Na/Np. For example for a regression of logs of Na/Np, wherein only 0.01 < Na/Np < 0.10 points are to be included, specify min and max values of -2 and -1.

All scatter plot output pages show:
The time span, Y and X parameter choices, numbers of
points selected/included and any filters (constraints) used;
The scatter plot and best-fit regression line;
The regression approach used (delta-Y or perpdist)
The fit equation y=a+b*x with values for a and b
The Pearson cross-correlation coefficient Cr

For the perpdist method, the following parameters are
also shown on the output pages:
Uncertainties in a and b;
Chi-squared and related probability q;
Root weighted mean square value of Yi-Y(Xi)
    [=SQRT{chi**2/Sum(1/sigma_i**2)}]
For the distribution function interface, the user specifies one parameter from one source. He/she also specifies a time span and filtering conditions for the selected parameter and/or for any other parameters. (Filtering works as described in the preceding discussion of scatter plots.) Finally, the user specifies a bin width (in units natural to the selected parameter) for the distribution function. Output consists of the distribution function plot and, listed, the number of points, mean value, median value, and standard deviation about the mean. Choosing "0" for bin width suppresses generation of a distribution function and yields number of points, mean, minimum and maximum values and the standard deviation.



If you have any questions/comments about the OMNWeb Plus, contact Dr. Natalia Papitashvili,Mail Code 672, NASA/Goddard Space Flight Center, Greenbelt, MD 20771

NASA Official: Dr. Robert McGuire, Head of the Space Physics Data Facility