Fig. 5

\(\chi ^2\) values and WRMS post-fit residuals. a \(\chi ^2\) values and b WRMS post-fit residuals for about 2700 VLBI sessions between 1993 and 2014 and different solution setups including a reference solution (black crosses), a simple solution with a constant additional noise term (purple triangles), the Gipson et al. (2008) approach (green circles) and the turbulence-based solution (brown stars). The gray dashed line in a represents \(\chi ^2 = 1\)