The 2010 season was the third full season for the GeoBasis programme with a field season from May to late October.

2010 was the warmest year registered since the air temperature measurements were initiated in 1866 in Nuuk. In 2010, the annual mean air temperature reached 2.6 °C and was thereby the 12th year within the total time series with an annual mean air temperature above 0 °C. The second warmest year in the time series was 1941 with an annual mean air temperature of 0.8 °C. In 2010, the monthly mean air temperatures in May, August, September, November and December were the highest measured during the period 1866-2010, which makes it a historically warm year.

The melting of snow and ice started in the beginning of May and by mid-June, all snow on the east side of the main river outlet had melted. The ice cover melt on the lakes was approximately one month earlier than in 2009. Due to logistical problems, only one snow survey was carried out in mid-April in co-operation with the ClimateBasis programme. Snow depth varied from 18 cm to 20 cm at the three soil microclimate stations and was 77 cm lower than in 2009.

The micrometeorological stations in Kobbefjord confirmed the warm climate in 2010 with a mean monthly air temperature of 11.3 °C at SoilFen in August compared to 8.7 °C in 2009 and only 7.4 °C in August 2008. Even at M500 (500 m a.s.l.) the mean monthly air temperature in August was 9.0 °C in 2010 compared to 7.1 °C in 2009 and 5.4 °C in 2008.

At the three automatic soil stations in the area; SoilFen, SoilEmp and SoilEmpSa the soil inter-annual variations in 2010 were quite similar to those documented in 2009 although the warmer climate in 2010 caused an average soil temperature of 3.3 °C compared to only 2.8 °C in 2009.

In 2010, 61 water samples were collected from late April to mid-October, which is the longest field season since the initiation of the GeoBasis monitoring programme in Kobbefjord. In situ measurements of river water temperature, conductivity and pH were conducted along with the water sampling. The river water temperature varies through the season 2010 with a minimum temperature of 1.7 °C measured 28 April and with a maximum temperature of 15.8 °C measured 19 July. The conductivity shows a significant decrease within the snow-melting period (April-May) to a level of 18 ± 1.5 μSc m^-1, while pH shows a constant level of 6.8 ± 0.4 from April to October 2010.

The temporal methane (CH₄) flux pattern in 2010 was similar to the pattern observed in the two previous years with a dome-shaped peak with maximum about a month after snow melt and declining to about half of the peak maximum towards the end of the summer season (around 1 September). During autumn, the methane flux continued to decrease consistently in September and October. The peak summer emissions in 2010 were 4 mg CH₄ m^-2 h^-1, which was low, compared to 8 mg CH₄ m^-2 h^-1 in 2009 and 5 mg CH₄ m^-2 h^-1 in 2008. The temporal variation in daily net exchange of CO₂ began 14 May and continued until 11 October. The period with net CO₂ uptake in 2010 lasted until 18 August, which was two days later than in 2008 and nine days earlier than in 2009. During this period, the fen accumulated 65.5 g C m^-2, which is 50 % higher than in 2009. The estimated net uptake period was approximately 81 days in 2010 or 42 % longer than in 2009, and the maximum daily uptake reached 3.14 g C m^-2 d^-1 compared to 1.48 g C m^-2 d^-1 in 2009.

In the 2010 season, the programme has been completed and major repairs have been carried out. The third full year has provided valuable learning to ensure improvements of the monitoring in the following years. All methods and sampling procedures are now described in details in the manual ‘GeoBasis – Guidelines and sampling procedures for the geographical monitoring programme of Nuuk Basic’, which can be downloaded from the website (www.nuuk-basic.dk).