Over on the thread we ran some time ago in response to Leif Svalgaard’s negative comments on Oulu NM data quality at WUWT, Professor Ilya Usoskin, chief scientist for Oulu NM station has provided an update, alerting me to a new paper which confirms his position:
Ilya Usoskin says:
Just to put a full stop in the discussion of the “trend” in the Oulu NM data.
There is a recent paper devoted to a thorough analysis of different NMs stability on the long-term scale (Ahluwalia & Ygbuhay, Testing baseline stability of some neutron monitors in Europe, Africa, and Asia, Adv. Space Res., 2013, in press)
The last sentence (summary) of the paper states that
“it is suggested that Oulu neutron monitor may be a good standard for future comparisons of the baselines over longer intervals of time.”
Ahluwalia is one of the pioneers of cosmic ray studies by NM is definitely among the best experts in the field.
Here is the abstract:
For six decades, the global network of neutron monitors (NMs) has provided a continuous stream of very valuable data to the heliophysics community, leading to many insights into the myriad modes of charged particle transport in the tangled magnetic fields that permeate the 3D heliosphere. Earlier, Ahluwalia and Ygbuhay  reported on the drifts in some high latitude NM counting rates in the American zone. We continue our enquiry by testing the stability of the counting rate baselines for some NMs operating in Europe, Africa, and Asia. The data from these detectors have been extremely valuable for the short-term time variation studies, but caution is advised in using the data for long-term studies from NMs with baselines that are drifting for cause(s) unknown.
From the conclusion:
[I]t is suggested that Oulu neutron monitor may be a good standard for future comparisons of the baselines over longer intervals of time.