Incoming Neutron Flux Corrections for Cosmic‐Ray Soil and Snow Sensors Using the Global Neutron Monitor Network

Abstract

AbstractCosmic‐ray neutron sensors (CRNS) have been used in many studies for measuring soil moisture and snow pack over intermediate scales. Corrections for barometric pressure and atmospheric humidity are well established, however, corrections for the effect of solar activity on neutron intensity rates have been overly simplistic, typically relying on one neutron monitor station and accounting for latitude and elevation crudely or not at all. Recognizing the lack of a generalized and scientifically robust approach to neutron intensity correction, we developed a new approach for correcting CRNS count rates based on analysis of data from 110 quality‐controlled neutron monitor stations from around the world spanning more than seven decades. Count rates from each monitor were plotted against the count rates from Climax, CO, USA or Jungfraujoch, Switzerland depending on the time period covered. Relationships between relative counting rates at the site of interest versus the reference neutron monitors were found to be strongly linear. The slope and intercept of these linear relation are both dependent on a scaling factor referred to as , which was shown to increase with increasing geomagnetic latitude and elevation. This dependence was represented using an empirical relationship based on a single reference neutron monitor. This generalized approach enables to be derived for any location on Earth and also lends itself to roving CRNS studies. The correction procedure also includes a location‐dependent normalization factor which enables easy substitution of an alternative reference neutron monitor into the correction procedure.