To assess climatic variability, they studied the samples of snow-and-firn deposits from four wells up to 70.2 metres deep. Having measured electrical conductivity of the core, the scientists identified the absolute age markers, i.e. the layers containing the products of known volcanic eruptions. The studies have made it possible to simulate a detailed summary profile of the density of the snow-and-firn strata from the surface up to the depth of 70.2 metres, measure its isotopic composition and improve the methodology of paleoclimatic reconstructions.
The institute experts have found out that over the past 2,200 years until the early 19th century, a slight cooling and a decrease in snow accumulation rate were observed in the Lake Vostok area. But over the past 200 years, the situation has changed, i.e. the temperature and the rate of snow accumulation increased. The rate of temperature change recorded at the Vostok meteorological station was 1.6 degrees per hundred years. When compared with the paleodata from ice cores, we cannot say that current temperature exceeds the limits of natural variability. At the same time, the average rate of snow accumulation in the last half century was the highest in 2200 years.
“Antarctica is a treasure trove of valuable climate information. Based on the core samples from the depths of the glacier, we obtain data on climate changes over hundreds of thousands of years before our era. At the same time, studies of the upper layers of snow are extremely important for understanding the most recent climate changes and allow us to speak with great accuracy about the transformations that occurred over the past centuries,” says Alexander Makarov, Director of the Arctic and Antarctic Research Institute.
During the seasonal expedition, the AARI specialists also made the first ever scientific trip to the area of Ice Divide B, one of the last large blank spots of Antarctica. They measured the accumulation rate and the isotopic composition of the snow strata. The newly obtained data support the suggestion that Ice Divide B could be a promising location for a new deep drilling project to extract the ancient ice up to 1.5 million years old.