Selective factors in Sun‐weather research

The extensive body of investigations of apparent correlations between solar wind/IMF disturbances and subsequent changes in the vorticity of the winter troposphere, which we designate as SV, is reviewed as representative of the search for sun‐weather relationships. Research on aspects of SV has for more than a decade been a dominant and controversial thrust in the search for links between short‐term solar variations and associated changes in the lower atmosphere. In particular, correlations identified between IMF sector boundary passages and subsequent decreases in the tropospheric vorticity, while not ubiquitous, continue to be perceived as one of the more credible sets of evidence for possible sun‐weather responses. We identify uncertainties in this research, which appear to have contributed inappropriate biases on both sides of the issue of the credibility of the SV response. Analyses leading to either positive or negative conclusions have generally concentrated upon the statistical procedures and have typically not addressed either the choice of parameters or the selective factors involved in the physical relationships existing between parameters. Thus we find that investigations of SV have characteristically lacked sufficient rigor for substantial conclusions to be drawn. Nonetheless, throughout the investigations on the subject a thread of observational evidence persists, suggestive of the possible associations between external forcing and atmospheric change. The obvious significance of such a possibility in our view clearly encourages further investigation. However, we strongly recommend that the research be conducted in a more interdisciplinary manner, emphasizing the variable physical relationships and the secular change in these relationships, selective factors which are known to exist between the variables believed critical to the problem.