A recent study by scientists in Xinjiang Institute of Ecology and Geography (XIEG) reveals that the snowfall in the Tibetan Plateau has undergone different trends since the year of 1961 along with the aggravation of global climate change.
The study, published in recent issue of Journal of Geophysical Research-Atmospheres, showed a large spatial variation of snowfall trends. The eastern and northeastern areas have seen a decrease of snowfall, while the central and western parts have a snowfall increase at higher altitude.
Tibetan glaciers have been shrinking in the last decades. Ice loss at high elevations threatens water supply for hundreds of millions of people. Snowfall is a critical source of glaciers in the Tibetan Plateau. However, snowfall in the Tibetan Plateau is undergoing changes due to temperature rising in the area.
“Snow is also an important reservoir of water and acts as a buffer in the hydrological system controlling river discharge and associated environmental processes and hazards,” said CHEN Yaning, a scientist with XIEG.
CHEN and his team studied the spatial and temporal variations of snowfall using 71 stations across the Tibetan Plateau for the last half century.
Their study showed an increase of snowfall in the early period. But the plateau endured a rapid decrease of snowfall since the year of 1981, especially in the east and at moderate elevations around 2,000 meters above sea-level.
The altitude of 3,396 meters above sea-level was identified as the turning point for the snowfall trends. This echoes CHEN’s study that the Tibetan Plateau sees an increase in snowfall in most areas.
Temperature was proved to be an important factor controlling the snowfall. Maximum snowfall occurs when air temperatures range between 1 and 2°C. When the temperature increases above the threshold, snowfall decreases. And when the temperature increases below the point, snowfall increases.
The threshold may explain much of the variation in snowfall trends, including regional, temporal, seasonal, and elevational contrasts, according to CHEN.