Axel Schweiger

Selected Projects

MIZMAS: Modeling the Evolution of Ice Thickness and Floe Size Distributions in the Marginal Ice Zone of the Chukchi and Beaufort Seas
The marginal ice zone (MIZ) is generally defined as a transition region from open water to pack ice with changing concentration, thickness, and ice floe sizes and shapes. The state of sea ice in the MIZ is currently modeled by an ice thickness distribution (ITD) that provides no information on the geometry of the ice pack, i.e., no description of the floe size distribution (FSD). This is not optimal, given that the FSD impacts ice strength and roughness, ice melt and growth, air–sea fluxes, and surface wave propagation. The FSD is in turn influenced by many of these processes.At present,…
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Atmospheric Profiles, Clouds and the Evolution of Sea Ice Cover in the Beaufort and Chukchi Seas
The role and magnitude of feedback processes, such as the ice-albedo feedback cannot be observed. They must be diagnosed from validated models that include the appropriate physics. For example, observational studies, attempting to discern the effect of clouds on sea ice (e.g. Schweiger et al 2008) confront the difficulty of separating cloud variability from other changes, such as atmospheric circulation. Model experiments that can isolate the role of a specific mechanism (e.g. Bitz, 2009) are needed to test and advance our current understanding of feedbacks in the atmosphere-ice-ocean system and to ultimately improve predictive capabilities for weather and climate. The…
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Path-P: TOVS Polar Pathfinder Gridded Daily Arctic Atmospheric Data from TOVS
This data set contains Arctic TOVS-derived Level-3 atmospheric parameters obtained using the physical-statistical retrieval method of Chedin et al. (1985, Improved Iteration Inversion Algorithm, 3I). The method has been improved for use in sea ice-covered areas (Francis 1994) and the data set has been designed to address the particular needs of the Polar research community. The data set represents the so called Path-P as designated by the TOVS Science Working Group. This research is part of the EOS Interdisciplinary Science (IDS) effort POLar Exchange at the Sea surface (POLES) Funding for this project has been provided by the NOAA/NASA Pathfinder Program.
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Impacts of Reduced Sea Ice on Atmospheric Heat, Precipitation Rates, and Ice Production
In recent years the ice extent in the Arctic has been much reduced from that of historical norms and the ice-albedo feedback is often cited as a major factor in causing this accelerated summer ice retreat. An important countervailing feedback is the ice thickness-growth feedback wherein thin ice grows much more quickly in the winter than thick ice. The strength of this negative feedback mechanism depends on the rate heat is lost from the surface to the atmosphere. The primary objectives of this project are to better understand how rapidly the extra summer heat absorbed in the Arctic Ocean in…
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Bias-Corrected Sea Ice Thickness from Satellite, Aircraft, and Subsurface Measurements
The primary objective of this research is to construct a comprehensive bias-corrected sea ice thickness record and use it to better quantify and understand the dramatic changes that have been observed in the Arctic ice pack. To do this all available Arctic sea ice thickness observations will be integrated, from satellite, aircraft, and subsurface measurements, and used to identify and correct systematic errors through comparisons with a common reference. With the resultant record four science questions will be answered:• What are the systematic differences between different measurement systems for sea ice thickness?• What are the spatial patterns in the trends…
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Response of Cloud Cover to Changes in Sea Ice
Clouds play a major role in the arctic surface energy balance controlling the growth and melt of sea ice. At the same time the processes involved in the formation, maintenance and dissipation of cloud cover over the Arctic Ocean are thought to be strongly influenced by the sea ice itself. This project will advance the understanding of this interaction and feedback by asking: What is the response of Arctic clouds to diminishing sea ice?
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Arctic Sea Ice Volume Anomaly
The Arctic Sea Ice Volume Anomaly time series is calculated using the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) developed at APL/PSC. Updates will be generated at approximately monthly intervals.
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The Fate of Summertime Arctic Ocean Heating: A Study of Ice-Albedo Feedback on Seasonal to Interannual Time Scales
PI: Mike Steele; Co-I Ron Lindsay, Axel Schweiger, Jinlun Zhang The main objective of this study is to determine the fate of solar energy absorbed by the arctic seas during summer, with a specific focus on its impact on the sea ice pack. Investigators further seek to understand the fate of this heat during the winter and even beyond to the following summer.
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Arctic Surface Air Temperatures for the Past 100 Years
This project will produce authoritative SAT data sets covering the Arctic Ocean from 1901 to present, which will be used to better understand Arctic climate change.
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Projections of an Ice-Diminished Arctic Ocean – Retrospection and Future Projection
Significant changes in arctic climate have been detected in recent years. One of the most striking changes is the decline of sea ice concurrent with changes in atmospheric circulation and increased surface air temperature.
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TOVS Polar Pathfinder Path-P Project
The purpose of this project is to improve satellite retrievals of atmospheric temperature, humidity and clouds. Retrievals are based on the physical-statistical retrieval method of Chedin et al. (1985, Improved Iteration Inversion Algorithm, 3I). The method has been improved for use in sea ice-covered areas (Francis 1994) and the data set has been designed to address the particular needs of the Polar research community. The data set represents the so called Path-P as designated by the TOVS Science Working Group.

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