Contemporaneous Relationships between Global Radiation and Heating Degree Days during Severe Winters in the United States

Abstract

The global radiation climate associated with anomalously cold winter months and cold winters is analyzed for the contiguous United States. The radiation data consist of rehabilitated measured and modeled monthly values of global radiation on both horizontal and tilted surfaces from 116 SOLMET stations in the contiguous United States. The period of record for these stations is 1953-75, but it is extended to cover the years 1953-80 by using percent of possible sunshine (PoPS) data. On the average the central portions of the United States receive significantly more global radiation than areas east of the Mississippi, but the radiation climate during anomalously cold winters is found to be substantially different from the mean radiation climate. Results indicate that in general, during anomalously cold winter months many eastern portions of the United States receive significantly more (up to 30% more on tilted surfaces) global radiation than normal, whereas in the central United States, particularly in the southern half, less than normal global radiation is received (up to 20% less on tilted surfaces) during the unusually cold winter months. Similar relationships are also reflected over longer averaging periods, i.e., entire winters and heating seasons. As a result solar heating systems have the potential to perform similarly in the eastern and central United States during anomalously cold winters in each area.