Dear dr Ding,
Thank you for replying here at the ASIF.
What I'm wondering about after reading your paper is how it relates to the work of Maslowski et al 2014:
http://www.iopan.gda.pl/profima/Strona%20RO/chapter_5.pdfThey say:
“Based on our model results and limited observations, we found that heat content of the Western Arctic ocean in the top 120 m has been increasing since the late 1990s and appears to be contributing to the rapid sea ice decline there. Our model analysis implies that the advection of warm water from Bering Strait regulates the retreat of sea ice and contributes to the relatively high surface air-sea fluxes over the Chukchi shelf. Earlier ice melt in the Chukchi Sea allows increased absorption of solar radiation and warming of water over the shelf, before it is exported into the Beaufort Sea where it can further contribute to sea ice melt. Based on evidence from observations and from our model, we argue that not all the heat content in the western Arctic Ocean gets removed back to the atmosphere every year before freezing in fall and early winter. We hypothesize that instead the remaining heat above the halocline and below the mixed layer acts to reduce sea ice growth in winter and preconditions an earlier ice melt each year, which further increases heat content in the region, thus resulting in a positive feedback accelerating summer reduction of the sea ice cover. The presence and spreading of a subsurface heat source in the western Arctic Ocean and the large-scale sea ice drift of the Beaufort Gyre help explain why the sea ice has continued to decline most dramatically in that part of the Arctic Ocean, even when large-scale atmospheric conditions were not always most favorable to such a decline (i.e. when the Arctic Oscillation Index was neutral or extremely negative).”
Earlier Maslowski et al 2012 had said:
http://www.oc.nps.edu/NAME/Maslowski%20et%20al.%202012%20EPS%20Future%20of%20Arctic%20Sea%20Ice.pdf“a system-level understanding of critical Arctic processes and feedbacks is still lacking. To better understand the past and present states and estimate future trajectories of Arctic sea ice and climate, we argue that it is critical to advance hierarchical regional climate modeling and coordinate it with the design of an integrated Arctic observing system to constrain models…
There are many Arctic climatic processes that are omitted from, or poorly represented in, most current-generation GCMs. These processes include the following: oceanic eddies, tides, fronts, buoyancy-driven coastal and boundary currents, cold halocline, dense water plumes and convection, double diffusion, surface/bottom mixed layer, sea ice–thickness distribution, concentration, deformation, drift and export, fast ice, snow cover, melt ponds and surface albedo, atmospheric loading, clouds and fronts, ice sheets/caps and mountain glaciers, permafrost, river runoff, and air–sea ice–land interactions and coupling…
the development and use of high-resolution regional Arctic climate and system models and process-level subsystem models are important stepping stones in the coming decade for dedicated studies of regional processes and feedbacks, tests of new parameterizations and ensemble simulations, and the prediction of sea ice and other components of the Arctic System in a warming climate.”
And more recently Notz et al 2016 say:
http://www.geosci-model-dev.net/9/3427/2016/gmd-9-3427-2016.pdf“it is sobering to see to which degree simulations of its past and future evolution differ across large-scale coupled models (e.g. Massonnet et al., 2012; Stroeve et al., 2012), how much retrieved sea-ice properties from one satellite product differ from another satellite product (e.g. Meier and Notz, 2010; Ivanova et al., 2015), and in how many aspects the simulations and observations differ from each other (e.g. Massonnet et al., 2012; Stroeve et al., 2012; Turner et al., 2013; Stroeve et al., 2014; Gagné et al., 2015; Shu et al., 2015).We do not yet know how much these differences are irreducible, for example because they are due to internal variability of the climate system, and how much they reflect biases in the model’s representation of the functioning of the climate system in high latitudes. This lack of understanding hinders further improvements of our models, an identification of observational needs, and a robust assessment of the most likely future evolution of sea ice in response to the ongoing climatic changes on Earth.”
I guess this comes down to the question AndrewB asks above about how confident we can be about the model results of your recent paper. Are these models good enough yet to warrant our confidence in them, or should we be quite sceptical still until they have been substantially improved, as Maslowski et al and Notz et al seem to imply?