Estimating the Proportion of Monthly Precipitation that Falls in Solid Form

Abstract

In applications where a monthly temporal resolution is employed, an important variable is the proportion of monthly precipitation that falls in solid form. Globally applicable equations for estimating this variable developed by previously published research are reevaluated. A revised equation developed 20 years ago by the lead author for climatological analysis works well for long-term data but not for actual monthly averages. A new equation, therefore, is developed for use with monthly data using an Arctic database of stations above 50°N latitude. These two equations have mean absolute fit errors of 0.0569 and 0.0614, respectively. The data were split into four regions?North America, northern Europe, northern Asia, and Greenland?and were also evaluated for the effect of elevation or seasonality influences. Results suggest that seasonality also is an important variable, particularly to differentiate between midwinter and transition months (i.e., October and April).