Changes in surface albedo and air temperature at Tartu, Estonia

Abstract

Changes in surface albedo, the duration of snow cover, and air temperature have been studied on the basis of observations made at the Tartu-Tõravere Actinometric Station between 1953 and 1994. Surface albedo has decreased substantially during the latest 42 years, especially in March (-21%) and April (-13%) due to the reduced duration of snow cover by 15—16 days in March and April. This reduction coincided with an increase in temperature over the same period, mainly observed in winter (up to 4.0 °C in March). The seasonal decrease in albedo has intensified absorption of radiation in the surface and thereby contributed to a rise in air temperature.