Earth Insolation and Tendencies of the Variation of Alpine Ice Resources

Abstract

On the basis of high-precision astronomical ephemeris with a high spatial and temporal resolution, the insolation of the Earth at the upper boundary of the atmosphere was calculated for the period from 3000 BC to 2999 AD. The differences from the earlier calculations of insolation are associated with the initial astronomical data and new calculation algorithms. In our calculations of insolation, the time interval of 5999 years and the entire surface of the Earth have been covered in detail. The Earth is not identified with a sphere, but is approximated by an ellipsoid. Previously, calculations of high-frequency variations in insolation were performed for individual parallels (in space), and in time for four or five separate points of the year (equinoxes, solstices and, sometimes, points with a geocentric longitude of 120 degrees). We have calculated insolation for the surface of latitudinal zones at 1° latitude and time intervals equal to 1/360 of the duration of a tropical year (approximately a day). Correlation analysis of the total mass balance of alpine glaciers (for the period from the balance years 1948/1949 to 2009/2010) with summer and winter insolation and summer, winter and annual insolation contrast of the northern hemisphere, which in a summarized forms (by regions of heat source and sink) reflects long-term changes in the meridional insolation gradient. It has been determined that the long-term variability in the total mass balance of alpine glaciers on average (for glaciers covered by balance observations) is accounted for by the trend at 94.3%. The trend to a reduction of alpine glaciers by an average of 90.6% is determined by the annual insolation contrast, which reflects an increase in the meridional heat transfer, as determined by an increase in the meridional contrast of radiant energy (on the Earth’s surface, excluding the atmosphere). Based on the close correlations determined by using a regression model, a forecast of the total mass balance of glaciers up to 2050 AD was made, which indicates a catastrophic development of the degradation of the modern glaciation of the Alps.