Figure 12: Daily latent heat flux as a function of atmospheric stability (ζ=\(\frac{z}{L_{\text{Ob}}}\) where z is the measured height andLOb refers to the Obukhov length) for the ice-free periods (15 May to 31 December) from 2018 to 2021.
Figure 13 presents the 2018, 2020 and 2021 cumulative heat storage ΔHS calculated over the 70-m water column. Heat storage started in spring and ended in early September (a 3.5-month period), with maximum values of 2000 MJ m−2 for 2018 and 2021 and 1700 MJ m−2 for 2020. Heat release followed and lasted about 4 months until ice-on. The heat release rate was lower from September to mid-November compared to mid-November to the end of December: 13 MJ m−2 day−1compared to 21.7 MJ m−2 day−1 for 2018. Overall, heat storage exhibited larger day-to-day fluctuations than heat release.