Hall, A. Dee, D. P. et al. It is noted that ice export from the fan-shaped area and its interannual variation (green lines in Fig. These suggest that the divergent ice motion in the early melt season can be a trigger of ice melt acceleration through ice-ocean albedo feedback. Internet Explorer). If an equivalent area of ice is replaced by water or land, (having a lower albedo value) reflects less and absorbs more energy, resulting in a warmer Earth. For sea ice drift velocity, we use the dataset48 derived from a wide variety of sensors such as AMSR-E, SSM/I, AVHRR, IABP Buoys, and etc., provided by NSIDC. 36, L15501 (2009). 109, C8007 (2004). The volume of ice melt and ice divergence are estimated from ice concentration and ice drift data as schematically shown in Supplementary Fig. J. Clim. September 2018 Schneider, S. H. & Dickinson, R. E. Climate modeling. Res. where \(\overline{Div}\) is the mean ice divergence, \(\bar{u}\) is the mean ice velocity, \(\overline{C}\) is the mean ice concentration, δ In the early melt season, the analysis area is mostly covered by sea ice with δ Greenland ice sheet mass loss has accelerated in the past decade responding to combined glacier discharge and surface melt water runoff increases. April 2016 Haruhiko Kashiwase. June 2017 Relationship between ice decay and solar heating through open water in the Antarctic sea ice zone. & Parkinson, C. L. Arctic sea ice variability and trends, 1979–2010. 114, D18204 (2009). September 2017 23, 3888–3906 (2010). Since the shortwave radiation, which does not vary as much from year to year, is dominant in the net heat flux during the summer season, the error in Qu is mostly due to the uncertainty in the sea ice concentration dataset. Because of the ice albedo effect, relatively small shifts in temperature at the poles may cause major climactic fluctuations. Snow and Ice Data Cent., Boulder, Colo (2004, updated 2012). J. Geophys. The model is based on assumptions similar to those in the heat budget analysis: only heat input through the open water fraction, Fw, is used for ice area decrease through melt (Fig. Bekryaev, R. V., Polyakov, I. V. & Alexeev, V. A. i Ice and snow are white, which means that they reflect the sun's rays—or, to put it another way, they have very high albedos. Res. 118, 2408–2425 (2013). & Marsan, D. Positive trend in the mean speed and deformation rate of Arctic sea ice, 1979–2007. April 2019 Ice and snow are white, which means that they reflect the sun's rays—or, to put it another way, they have very high albedos. December 2017 4, 353–357 (2014). volume 7, Article number: 8170 (2017) October 2018 The simplified model was applied for the rectangular area. Res. ρ This feedback arises from the simple fact that ice is more reflective (that is, has a higher albedo) than land or water surfaces. Then, we used this for the calculations of Qm and Adv (see Methods). November 2016 3d and e) point to the key role of ice divergence in the context of feedback processes. The sea ice is melting rapidly in the Arctic Ocean. Other factors such as changes in atmospheric circulation patterns38, influence of cloud cover39, 40, longwave radiative forcing due to anthropogenic CO2 emission41, melt pond distribution in the early summer season42, release of the solar heat stored in a near-surface layer of the ocean43, and increases in the heat inflow through Bering Strait44 may also contribute to drastic ice reductions. 6, 881–889 (2012). commenting. (e) Scatter plot of Qu and Qm. Sci. On the specific heat of sea ice. Nihashi, S., Ohshima, K. I. 42, 8057–8063 (2015). i Correspondence to & McPhee, M. G. Solar heating of the Arctic mixed layer. Acad. To reduce the influence of errors in sea ice concentration data, we set Δt as 10 days. Lett. Thus, this early Div is also well correlated with the yearly value of Qm (Fig. J. Clim. During summer, absorbed solar energy, modulated at the surface primarily by albedo, is the dominant factor governing surface melt variability in the ablation area. Source: ""Arctic Sea Ice Extent,"" National Snow and Ice Data Center, October 12, 2009. http://inside.org. MY Eicken, H., Grenfell, T. C., Perovich, D. K., Richter-Menge, J. Estimates from the heat budget analysis and satellite observations show that Qu corresponds well quantitatively with Qm both for seasonal and interannual variations (Fig. Riiherä, A., Manninen, T., Laine, V., Andersson, K. & Kasper, K. CLARA-SAL: a global 28 yr timeseries of Earth’s black-sky surface albedo. Markus, T., Stroeve, J. C. & Miller, J. Change To obtain 2). This increased heat uptake can explain about 70% of the observed 2.1-fold increase in total sea ice melt (from 121 MJ m−2 to 257 MJ m−2).