ASCOS

To understand the fast-changing Arctic climate, climate models are a necessary tool. Yet the current climate models are unable to reproduce the current Arctic climate satisfactorily and the spread between different climate models when projecting change over the next several decades is larger in the Arctic than elsewhere on Earth. A major problem for these models is that many of the processes that determine the climate are not resolved. Instead the effects of these processes are described in a statistical fashion – as function of the larger-scale features of climate. Developing such descriptions – parameterizations – has an unavoidable empirical component. One can never parameterize what is not understood! This is a global problem but the Arctic stands out because of it inaccessibility. There is a lack of detailed observations of climate relevant processes in the Arctic simply because it is difficult to get there! This is what ASCOS is all about – obtaining high-quality observations of cloud-related processes in a very remote area. 

Icebreaker Oden in poor ice south of 87N The central Arctic Ocean is far away from civilization and there are no permanent landmasses where observation stations can be located or where field experiments can be easily deployed. Moreover, the Arctic environment is harsh and difficult on both man and on instruments. The winter Arctic is long, dark and cold, while the summer Arctic is very moist and the ice is sometimes treacherously soft and fragile. Deploying advanced and expensive instrumentation in the central Arctic therefore in practice relies on icebreakers. Sustained long-term observations from the Arctic are for this reason not common; the central Arctic ice is only accessible by a limited set of high ice-class icebreakers. Examples of this type of deployment are the Surface Heat Balance of the Arctic (SHEBA), onboard the Canadian icebreaker Des Groseillers frozen into the ice north of Alaska for a full year 1997-98, and the Arctic Ocean Experiment 2001 (AOE-2001), onboard the Swedish icebreaker Oden, drifting with the ice for almost a month near the pole as a part of a two-month experiment in summer of 2001. The Oden has previously been used for research in the Arctic on several occasions.

Areal view of ASCOS ice floe from helicopterASCOS is a part of a Swedish commitment to the International Polar Year (IPY) and was also deployed onboard the Oden, from 1 August to 9 September, 2008. The main activity again called a three week ice drift, with Oden moored to an ice floe and drifting with it near 87N 15W. Heavy, bulky and/or expensive instrumentation was operated onboard the icebreaker, which also served as a “hotel” for the experiment participants and crew. The Oden was also the air base for the helicopter was be used both to deploy instruments on the ice and to fly instruments, getting vertical profiles of important variables. We were also the focal point for the NASA DC-8 flights that were carried out from Kiruna, Sweden, in support of the sister-project AMISA. Instruments that require undisturbed (by the ship) conditions were deployed on the ice. The picture to the right shows the deployment on “our” ice floe. 

Pictures below shows examples of the instruments deployed during ASCOS outlined according to discipline across the ice and vertically. The lower right corner in this composite image shows the marine biology sampling, of bulk water and surface-layer water (with the little boat), and the “bubble camera” observing the gas bubbles in the water believed to be the vehicle for transfort of particulate matter out of the ocean. The lower left section shows the upper ocean physical oceanography observations below the ice and above it are the micrometeorological observations with its two masts, a sodar for wind profiles and measurements of the radiation fluxes at the surface. Also part of the micrometeorological measurements where the tethered balloon profiling on the far right that together with the releases of regular radiosoundings measured the vertical structure of the atmosphere with in situ sensors. The upper left corner shows a portion of the remote sensing instruments on board with two cloud radars, a wind profiler and several microwave radiometers. A large portion of the instruments were aerosol and atmospheric chemistry measurements in a suite of containers on the fourth deck with an air intake on two masts sticking up on the port side of the ship. The bridge roof – the seventh deck was also cluttered with a variety of instruments, among them the ships weather station, two radiometers, a lidar and a suite of collectors for atmospheric chemistry and aerosol sampling. Finally, ASCOS had its own aircraft program; the ships helicopter was used for aerosol and chemistry profiling. And then we also had visits from the NASA DC-8 research aircraft in support of our sister project AMISA.

Composit of ASCOS observation systems

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Cruise track of ASCOS