Considerable amount of water evaporates from glacial lakes in the summer in Antarctica

Evaporation is a result of liquid turning into a gas. This process is generally slower or faster depending on whether ambient temperature is colder or warmer. In Antarctica, where liquid water is rare, the evaporation process exists only in summer when numerous glacial lakes appear over the ice surface, on its contact to rocks and ice-free oases.

Even though the total surface area of the glacial lakes is relatively small, locally they may remarkably increase the amount of water in the air because of evaporation. The result of a new study shows that the summertime evaporation over the surface of a glacial lake can reach up to 5 mm per day which is five times more than earlier estimated.

The evaporation is driven by changes in wind speed rather than near surface temperature. Intensive evaporation may provide the local moisture source allowing to form rains falling in the temperature near freezing point; the evaporation also may contribute to form fogs in the ice-free oases. Such weather events are dangerous for summer logistic operations in Antarctica.

In summer, numerous glacial lakes are recently detected over the East Antarctic coast. These lakes may keep megatons of liquid water whose presence affects energy and mass balance of the land surface. The intensification of the evaporation process is one of the effects. The research gives the results of the direct measurements of the summertime evaporation over the surface of one glacial lake located in Antarctica. Known indirect methods underestimated the evaporation over the lake's surface by up to 72%.

The results suggested the need to present the glacial lakes in numerical weather prediction systems and climate models. Ignoring them in a lake-rich region, such as the East Antarctic coast, may result in errors while predicting hazardous weather events in summer.

Further information: 

Elena Shevnina, Finnish Meteorological Institute, tel. +358 44 918 546; elena.shevnina@fmi.fi

Timo Vihma, Finnish Meteorological Institute, tel. +358 50 412 6365, timo.vihma@fmi.fi

Scientific article is available on The Cryosphere.

Reference: Shevnina, E., Potes, M., Vihma, T., Naakka, T., Dhote, P. R., and Thakur, P. K.: Evaporation over a glacial lake in Antarctica, The Cryosphere, 16, 3101–3121, https://doi.org/10.5194/tc-16-3101-2022, 2022.