Radiative energy budget and cloud radiative forcing in the daytime marginal sea ice zone during Arctic spring and summer
Abstract. Airborne measurements of the surface radiative energy budget (REB) collected in the area of the marginal sea ice zone (MIZ) close to Svalbard (Norway) during two campaigns conducted in early spring and and early summer are presented. From the data, the cloud radiative forcing was derived. The analysis is focussed on the impact of changing atmospheric thermodynamic conditions on the REB and on the linkage of sea ice properties and cloud radiative forcing (CRF). The observed two-mode longwave net irradiance frequency distributions above sea ice are compared with measurements from previous studies. The transition of both states (cloudy and cloud-free) from winter towards summer and the associated broadening of the modes is discussed as a function of the seasonal thermodynamic profiles and the surface type. The influence of cold air outbreaks (CAO) and warm air intrusions on the REB is illustrated for several case studies, whereby the source and sink terms of REB in the evolving CAO boundary layer are quantified. Furthermore, the role of thermodynamic profiles and the vertical location of clouds during on-ice flow is illustrated. The sea ice concentration was identified as the main driver of the shortwave cooling by the clouds. The longwave warming of clouds, estimated to about 75 W m−2, seems to be representative for this region, as compared to other studies. Simplified radiative transfer simulations of the frequently observed low-level boundary layer clouds and average thermodynamic profiles represent the observed radiative quantities fairly well. The simulations illustrate the delicate interplay of surface and cloud properties that modify the REB and CRF, and the challenges in quantifying trends in the Arctic REB induced by potential changes of the cloud optical thickness.
This preprint has been withdrawn.
Johannes Stapf et al.
Johannes Stapf et al.
Johannes Stapf et al.
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In this paper the authors use aircraft observations to study radiation budgets and cloud radiative forcing over sea ice, open water and the marginal ice zone. There is a wealth of very interesting information here and the study appears to be carefully performed carried out. However, the work is not done until its done and this manuscript needs a lot more work. I therefore recommend that it is rejected and encourage the authors to go back to the drawing board and make a new attempt.
The author instructions call for a concise text; this is anything but. It completely lacks organization; I gave up reading around page 20 or 21, still not sure if I actually had come to the results section, or if I were still in the introductory lead-up. Besides it would be about radiation, I still don’t see where this study is leading me and what important new finding it will lead up to. The text is much too long and contains too many different lines of thought without a clear connecting concept. It feels like a pile of detailed but unconnected case studies.
It also has too complicated and poorly explained plots; sometimes more and simpler plots are better than really ingenious constructions that are poorly explained. To top that off, the language is not very good. I get the feeling the authors are making a real effort to write “fancy” English, but the sentence structure is often strange with many short subordinate clauses piled on top of each other (German influence?), and in many cases sentences contains too many ideas. I was once told by a mentor: "One sentence, one thought"! Hard to stick to but useful to think about when writing.
I normally try and provide detailed comments when I review papers to help young scientists; I’m not an expert per see but have gained some experience over the years. But also here I gave up; comments are much too many. I’d be very happy to review a new version of this manuscript and provide detailed help, but it has to be organized and possibly split into more than one manuscript with some cohesive structure.
Make no mistake; I would really like for these resulats to be published! But this manuscript is not ready yet and if I were to recommend major revision, it might never be; hence reject and resubmit.