Arctic sea ice coverage appears to have reached its lowest extent for the year and the second-lowest amount recorded since the dawn of the satellite era, according to observations from the NASA-supported National Snow and Ice Data Center at the University of Colorado in Boulder.

While slightly above the record-low minimum set Sept. 16, 2007, this season further reinforces the strong negative trend in summer sea ice extent observed during the past 30 years. Before last year, the previous record low for September was 2005.

In March, when the Arctic reached its annual maximum sea ice coverage during the winter, scientists from NASA and the data center reported that thick, older sea ice was continuing to decline. According to NASA-processed satellite microwave data, this perennial ice used to cover 50-60 percent of the Arctic, but this winter it covered less than 30 percent. Perennial sea ice is the long-lived layer of ice that remains even when the surrounding short-lived seasonal sea ice melts to its minimum extent during the summer.

NASA scientists have been observing Arctic sea ice cover since 1979. NASA developed the capability to observe the extent and concentration of sea ice from space using passive microwave sensors.

The National Snow and Ice Data Center will issue an analysis of the possible causes behind this year's Arctic sea ice conditions during the first week of October. For updates, visit http://nsidc.org/arcticseaicenews.