80N Freezing Degree Days

"Freezing Degree Days" (FDD) are defined as the temperature below freezing. Here FDD use 0°C as the freezing point like the Polar Science Center. Other institutions use -1.8°C as the freezing point.

Long-term Graphs

Example:

1. Day: average Temp: -3°C

2. Day: average Temp: -5°C

3. Day: average Temp: -7°C

Total: 15°C

80°N Area in Detail

The climate average is based on ERA40, a reanalysis data set from ECMWF that has been applied to calculate daily mean temperatures (2m) for the period from 1958 to 2002.

Data Download

Data source: Danish Meteorological Institute:

http://ocean.dmi.dk/arctic/meant80n.uk.php

Orginal project by Andrew Slater:

http://cires1.colorado.edu/~aslater/ARCTIC_TAIR/index_80_t2m.html

This graph shows Freezing Degree days over the whole freezing season. The sea ice thickness can be estimated based on the following formula (Lebedev 1938):

Thickness (cm) = 1.33 * FDD (°C)^0.58

It is important to note that the calculated thickness using this formula only accounts for the freezing of sea water and not ice growth from snowfall, freezing rain or ridging. By using 0°C as the freezing point the formula matches measured ice thickness better.

More info at:

https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

When the graph goes up the year was colder than the 1958 - 2002 mean temperature. When the graph goes down the year was warmer.

Individual Years.

Individual Years anomaly.