The variability of signal intensity within each particular sample could be due to multiple reasons, and GC content may only explain partial variability of the WF. To quantify the signal fluctuation that can be attributed to the local GC content, we developed another measure called GC-wave factor (GCWF). This measure is simply the product of WF value and the absolute values of rGC: Intuitively, the WF and GCWF measures can be understood in this way: the WF function as a proxy for total signal fluctuation, but is more resilient to outliers than the standard deviation measure. The square of rGC can be considered as the fraction of variance explained by local GC content. Therefore, the GCWF score is a summary measure of the signal fluctuation explained by local GC content.
