Snow Cover Worldwide Is At Record Lows
December 4, 2012

Satellites See Record Low Worldwide Snow Cover

April Flowers for - Your Universe Online

A new European Space Agency (ESA) study of snow cover observed by satellites reveals record lows in Eurasia for June each year since 2008. Three of the past five years have seen record low cover in North America, as well.

Since satellite observations began some 45 years ago, this is the lowest June snow extent on record. Snow cover in June is falling faster than climate models have predicted. It is even disappearing faster than summertime Arctic sea ice.

Based on snow chart data from the U.S. National Oceanic and Atmospheric Administration, the results are consistent with indications of a decline in monthly-average snow mass. The monthly-average snow mass was published last year as part of ESA's GlobSnow project.

The researchers found that the maximum amount of snow across the Northern Hemisphere is slowly falling. Spring snow, on the other hand — particularly at high latitudes — is melting significantly earlier.

The GlobSnow report demonstrated a long-time series of snow mass from 1979 to 2012. It also produced a time-series of snow cover from 1995 to 2012, which is the first daily dataset of its kind for the Northern Hemisphere that extends over 30 years. The data is from satellite sensors measuring Earth's microwave emissions.

Changes in seasonal snow cover are important for the climate and hydrology. Information on snow mass and area is used to monitor and understand these changes. Since satellites observe large areas on a regular basis, they are the only way to obtain this information.

Reliable data on snow cover, in addition to having geophysical applications, can assist decision-makers and policy-makers in creating strategies to adapt to the changes. To aid in this, the European Environment Agency (EEA) has included GlobSnow results in their "Climate Change, Impacts and Vulnerability in Europe 2012" report.

“The satellite-derived information from GlobSnow on total snow mass provides us with an important indicator that helps us to monitor changes in European and Arctic climate,” notes Hans-Martin Fuessel of the EEA.

The GlobSnow project has been extended two years, ensuring continuity in the production of snow information and improving the data processing. All the data from the initial phase of GlobSnow will be reprocessed based on new methods.

The findings of this study were published in Geophysical Research Letters.