Historical Trend in Ice Thickness on the Piscataquis River in Central Maine

We analyzed a long-term record of ice thickness on the Piscataquis River in central Maine to determine whether there were temporal trends that were associated with climate warming. Trends in ice thickness were compared and correlated with regional time series of winter air temperature, heating degree days (HDD) , date of river ice-out, seasonal center-of-volume date (SCVD) (date on which half of the stream runoff volume during the period 1 Jan and 31 May has occurred), water temperature, and lake ice-out date. All of these variables except lake ice-out date showed significant temporal trends during the 20th century. Average ice thickness around 28 Feb