  We observe and analyse a long-lived corotating interaction region (CIR),
originating from a single coronal hole (CH), recurring in 27 consecutive
Carrington rotations 2057-2083 in the time period from June 2007 - May 2009. We
studied the in situ measurements of this long-lived CIR as well as the
corresponding depression in the cosmic ray (CR) count observed by SOHO/EPHIN
throughout different rotations. We performed a statistical analysis, as well as
the superposed epoch analysis, using relative values of the key parameters: the
total magnetic field strength, B, the magnetic field fluctuations, dBrms,
plasma flow speed, v, plasma density, n, plasma temperature, T , and the
SOHO/EPHIN F-detector particle count, and CR count. We find that the mirrored
CR count-time profile is correlated with that of the flow speed, ranging from
moderate to strong correlation, depending on the rotation. In addition, we find
that the CR count dip amplitude is correlated to the peak in the magnetic field
and flow speed of the CIR. These results are in agreement with previous
statistical studies. Finally, using the superposed epoch analysis, we obtain a
generic CIR example, which reflects the in situ properties of a typical CIR
well. Our results are better explained based on the combined
convection-diffusion approach of the CIR-related GCR modulation. Furthermore,
qualitatively, our results do not differ from those based on different CHs
samples. This indicates that the change of the physical properties of the
recurring CIR from one rotation to another is not qualitatively different from
the change of the physical properties of CIRs originating from different CHs.
Finally, the obtained generic CIR example, analyzed on the basis of superposed
epoch analysis, can be used as a reference for testing future models.
