Due to their high intensity of emission in the O VI 1031.9 and 1037.6Å lines , even small sunspots on the solar disk can strongly influence the intensity of the radiative scattering component of O VI lines in the corona .
Observations of O VI disk spectra show a 1032/1038 line intensity ratio of > 2.6 in a sunspot compared to quiet disk values of \sim 2 .
The enhancement of the 1032 line in comparison to the 1038 is likely due to interaction between molecular hydrogen emission from the sunspot and the chromospheric O ^ { 5 + } .
Modeling shows that a contribution from sunspots increases the coronal O VI 1032/1038 intensity ratio to values considerably higher than those achieved with a quiet disk or coronal hole spectrum .
Therefore a re-examination of flow velocities derived from UVCS/SOHO streamer observations must be made .
This modeling demonstrates that the inclusion of sunspots , when present , may lead to non-zero outflow velocities at lower heights in streamer cores in contrast to some existing model results .