Fig. 1.
Study area and locations of measurement points.
Fig. 2.
Number of days with ice cover (IC) at each station (top panel) and the ratio of the share of total ice cover (TIC) and border ice (BI) in the sum of days with ice cover (bottom panel).
Fig. 3.
Moving averages (5-year window) of dates on the first and last days of ice cover occurrence (sums of total ice and border ice).
Table 1.
Trend (1980–2020) and percentage change in the number of days with ice cover during the period 2001–2020 compared to the period 1980–2000 by month.
| Station code | % change in 2001–2020 compared to 1980–2000 | Trend [days per decade] | |||||
|---|---|---|---|---|---|---|---|
| Nov | Dec | Jan | Feb | Mar | Winter | ||
| H1 | –94.9 | –38.8 | –23.5 | –37.1 | –30.0 | –36.4 | –11.1*** |
| H2 | –93.5 | –30.3 | –14.1 | –25.2 | –15.0 | –25.8 | –8.9** |
| H3 | –54.3 | 0.7 | 16.6 | 5.0 | 15.7 | 4.9 | –3.0 |
| H4 | –73.8 | –9.6 | 4.4 | –12.3 | 0.0 | –7.0 | –4.1 |
| H5 | –67.6 | –5.3 | –5.0 | –14.9 | –19.3 | –13.1 | –6.7* |
| H6 | –84.5 | –8.5 | 3.7 | 11.2 | 24.5 | –0.6 | –0.8 |
| H7 | –95.2 | –28.1 | 2.8 | –17.7 | –1.4 | –16.5 | –5.0* |
| H8 | –75.9 | –29.8 | –5.3 | –34.5 | –20.8 | –25.4 | –9.0*** |
| H9 | –96.6 | –33.7 | –8.7 | –27.1 | –42.7 | –27.2 | –8.5** |
| H10 | –83.3 | –24.9 | –10.9 | –21.8 | –32.5 | –23.0 | –11.3*** |
| H11 | –80.7 | 5.9 | –2.3 | –29.2 | –2.3 | –14.2 | –4.9 |
| H12 | –67.3 | –23.4 | –13.0 | –29.8 | –32.1 | –27.0 | –11.4*** |
| H13 | –61.0 | –12.9 | –5.9 | –17.7 | –39.5 | –20.4 | –9.6*** |
Table 2.
Trends in average air temperature over the period 1980–2020 in the study area.
| Station code/dataset | Trend [°C per decade] | |||||
|---|---|---|---|---|---|---|
| Nov | Dec | Jan | Feb | Mar | Winter | |
| CRU-TS | 0.76*** | 0.40 | 0.21 | 0.63 | 0.62* | 0.47** |
| C1 | 0.87*** | 0.34 | 0.16 | 0.69 | 0.44 | 0.41* |
| C2 | 0.55** | 0.26 | 0.10 | 0.61 | 0.23 | 0.31 |
| C3 | 0.74** | 0.40 | 0.21 | 0.68 | 0.24 | 0.40* |
| C4 | 0.71* | 0.13 | 0.50 | 0.92* | 0.40 | 0.47** |
| C5 | 0.79*** | 0.19 | 0.23 | 0.64 | 0.21 | 0.37** |
| C6 | 0.85*** | 0.43 | 0.44 | 0.67* | 0.38 | 0.49** |
| C7 | 0.85*** | 0.44 | 0.38 | 0.76* | 0.26 | 0.49** |
Table 3.
Trends in water temperature at gauging stations.
Fig. 4.
Time series of streamflow at selected stations filtered using the MASH method for the period 1980–2020.
Table 4.
Trends in discharge at gauging stations.
| Station code | Trend [m3 s−1 per decade] | |||||
|---|---|---|---|---|---|---|
| Nov | Dec | Jan | Feb | Mar | Winter | |
| H1 | 0.80 | 0.19 | 0.45 | 1.33** | 0.90 | 0.73** |
| H2 | 0.14 | –0.15 | 0.05 | 0.72** | 0.23 | 0.14 |
| H3 | 0.15 | –0.09 | 0.09 | 0.82 | 0.17 | 0.20 |
| H4 | 0.13 | –0.16 | 0.26 | 1.62** | –0.31 | 0.11 |
| H5 | 1.08* | 0.11 | 0.47 | 1.17** | 0.55 | 0.74** |
| H6 | –0.01 | –0.18 | –0.22 | 0.32 | –0.60 | –0.23 |
| H7 | 0.04 | –0.17 | –0.19 | 0.89** | –0.65 | –0.03 |
| H8 | 0.04 | 0.02 | –0.03 | 0.55** | –0.28 | 0.03 |
| H9 | 1.42 | 0.05 | 0.69 | 2.68** | 1.10 | 1.24* |
| H10 | 1.14* | 0.20 | 0.43 | 1.83*** | 0.68 | 0.98** |
| H11 | 0.00 | –0.25 | 0.15 | 0.82** | –0.07 | 0.20 |
| H12 | 0.23 | –0.16 | 0.78* | 0.93** | 0.74 | 0.55* |
| H13 | 0.73 | 0.12 | 0.77* | 1.53** | 1.43* | 1.09*** |