Polistovsky bog is frozen to 16 centimeters deep
Annually with the onset of cold weather, Polistovsky Reserve employees start to monitor the process of freezing and subsequent thawing of the raised bog. Now, by the middle of winter, the surface of the bog has already frozen to a depth of 16 centimeters.
The depth of bog freezing is one of the parameters of environmental monitoring, which is conducted in Polistovsky Reserve to observe natural processes and fenomena. It allows you to monitor the thermal state of the bog massif and its relation with meteorological parameters. The measurement of the bog freezing depth has been carried out continuously for the last 10 years - since 2007.
Observations of the raised bog freezing are carried out by the employees of Polistovsky Reserve on the one route and two sites representing the most common raised bog communities of the Reserve - sedge-cotton grass-sphagnum, pine-cotton grass-shrub-sphagnum and ridge-hummock complex.
At each site, freezing is measured at 8 fixed points. The surface of the bog is freed from snow, then a piece of frozen peat is removed from the bog using special device and then height of the frozen column is measured. Measured peat is returned back to its original location.
Measurements of freezing of the bog massif begin with the transition of the average daily air temperature below 0°C. When a snow cover height is less than 15 cm, measurements are made every 5 days, above 15 cm - every 10 days. With the onset of spring, when the average daily air temperature passes through the 0°C mark in the positive direction, observations are made every 5 days, and when a frozen layer is less than 5 cm - observations are made daily.
This year, measurements of bog freezing depth in Polistovsky Reserve started in late November. According to the data on the 30th of November, the depth of freezing was 1 cm, and today its maximum value is already 16 cm. In one of the coldest winters during the observation period (2011-2012), the depth of freezing of the bog massif in Polistovsky Reserve reached 33.8 centimeters.