Whaling records and changes in Antarctic sea ice: consistency with historical records

Polar Record ◽  
2002 ◽  
Vol 38 (207) ◽  
pp. 355-358 ◽  
Author(s):  
William K. de la Mare
Keyword(s):  
Sea Ice ◽  
Complex Nature ◽  
Limited Data ◽  
Antarctic Sea Ice ◽  
Direct Observations ◽  
Ice Edge ◽  
Sea Ice Edge ◽  
Types Of Information ◽  
The Antarctic ◽  
The Relationship

AbstractA claim that there are substantial discrepancies between direct observations of the Antarctic sea-ice edge and the implicit sea-ice edge derived from whaling records is rebutted. The claimeddiscrepancies are shown to arise largely from comparing the two types of information from different dates. A date-corrected comparison shows generally good agreement between the southernmost limit of whaling and the most comprehensive of the early monthly ice charts of Antarctica. The remaining apparent discrepancies are accounted for either by very limited data or the complex nature of the ice edge in the region of the Weddell ice tongue. Correlation of the southernmost limits of whaling with direct observations of the ice edge provides the most powerful calibration of the relationship between them

scholarly journals Comparison between AMSR-E ASI sea-ice concentration product, MODIS and pseudo-ship observations of the Antarctic sea-ice edge

2015 ◽  
Vol 56 (69) ◽  
pp. 45-52 ◽  
Author(s):  
Xi Zhao ◽  
Haoyue Su ◽  
Alfred Stein ◽  
Xiaoping Pang
Keyword(s):  
Sea Ice ◽  
Average Distance ◽  
Sea Ice Concentration ◽  
Earth Observing System ◽  
Antarctic Sea Ice ◽  
Spatial Coverage ◽  
Ice Concentration ◽  
Ice Edge ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
The Antarctic

AbstractThe performance of passive microwave sea-ice concentration products in the marginal ice zone and at the ice edge draws much attention in accuracy assessments. In this study, we generated 917 pseudo-ship observations from four Moderate Resolution Imaging Spectroradiometer (MODIS) images based on the Antarctic Sea Ice Processes and Climate (ASPeCt) protocol to assess the quality of the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) ARTIST (Arctic Radiation and Turbulence Interaction STudy) Sea Ice (ASI) concentrations at the ice edge in Antarctica. The results indicate that the ASI pixels in the pseudo-ASPeCt observations have a mean ice concentration of 13% and are significantly different from the well-established 15% threshold. The average distance between the pseudo-ice edge and the 15% threshold contour is ~10 km. The correlation between the sea-ice concentration (SIC), SICASI and SICMODIS values at the ice edge was considerably lower than the high coefficients obtained from a transect analysis. Underestimation of SICASI occurred in summer, whereas no clear bias was observed in winter. The proposed method provides an opportunity to generate a new source of reference data in which the spatial coverage is wider and more flexible than in traditional in situ observations.

scholarly journals Observed Concentration Budgets of Arctic and Antarctic Sea Ice

2016 ◽  
Vol 29 (14) ◽  
pp. 5241-5249 ◽  
Author(s):  
Paul R. Holland ◽  
Noriaki Kimura
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Arctic Sea Ice ◽  
Ice Melting ◽  
Antarctic Sea Ice ◽  
Arctic Sea ◽  
Ice Concentration ◽  
Anthropogenic Contribution ◽  
Ice Edge ◽  
The Antarctic

Abstract In recent decades, Antarctic sea ice has expanded slightly while Arctic sea ice has contracted dramatically. The anthropogenic contribution to these changes cannot be fully assessed unless climate models are able to reproduce them. Process-based evaluation is needed to provide a clear view of the capabilities and limitations of such models. In this study, ice concentration and drift derived from AMSR-E data during 2003–10 are combined to derive a climatology of the ice concentration budget at both poles. This enables an observational decomposition of the seasonal dynamic and thermodynamic changes in ice cover. In both hemispheres, the results show spring ice loss dominated by ice melting. In other seasons ice divergence maintains freezing in the inner pack while advection causes melting at the ice edge, as ice is transported beyond the region where it is thermodynamically sustainable. Mechanical redistribution provides an important sink of ice concentration in the central Arctic and around the Antarctic coastline. This insight builds upon existing understanding of the sea ice cycle gained from ice and climate models, and the datasets may provide a valuable tool in validating such models in the future.

scholarly journals New estimates of Arctic and Antarctic sea ice extent during September 1964 from recovered Nimbus I satellite imagery

2013 ◽  
Vol 7 (1) ◽  
pp. 35-53 ◽  
Author(s):  
W. N. Meier ◽  
D. Gallaher ◽  
G. G. Campbell
Keyword(s):  
Sea Ice ◽  
Satellite Imagery ◽  
Passive Microwave ◽  
The Arctic ◽  
Large Decrease ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Ice Edge ◽  
The 1960S ◽  
The Antarctic

Abstract. Satellite imagery from the 1964 Nimbus I satellite has been recovered, digitized, and processed to estimate Arctic and Antarctic sea ice extent for September 1964. September is the month when the Arctic reaches its minimum annual extent and the Antarctic reaches its maximum. Images were manually analyzed over a three-week period to estimate the location of the ice edge and then composited to obtain a hemispheric average. Uncertainties were based on limitations in the image analysis and the variation of the ice cover over the three week period. The 1964 Antarctic extent is higher than estimates from the 1979–present passive microwave record, but is in accord with previous indications of higher extents during the 1960s. The Arctic 1964 extent was near the 1979–2000 average from the passive microwave record, suggesting relatively stable summer extents until the recent large decrease. This early satellite record puts the recently observed into a longer-term context.

Can Antarctic sea-ice extent be determined from whaling records?

Polar Record ◽  
2000 ◽  
Vol 36 (199) ◽  
pp. 345-347 ◽  
Author(s):  
Stephen Vaughan
Keyword(s):  
Sea Ice ◽  
Accurate Method ◽  
Reliable Information ◽  
New Method ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
The Subject ◽  
Ice Edge ◽  
Sea Ice Edge ◽  
Sighting Data

SummeryThe subject of retreating global sea-ice extent is a matter of grave concern, and any new method that promises reliable information about past ice-extent parameters must be welcomed. However, the method proposed by De la Mare should be viewed with caution for four reasons. First, his predictions of sea-ice extent do not correspond with known observations of sea-ice extent from research published in 1936 and 1972. Second, his predictions correlate much more closely with the whale-sighting data recorded by Hansen (1936). Third, since Hansen's sea-ice extent data do not correspond closely with his whalesighting data, it must be questioned whether whale-based data should be used for retrospective predictions relating to sea-ice extent. And finally, information from the IWC indicates that De la Mare's datasets are not considered accurate. Predicting sea-ice edge extent is complex, and, it would seem, a purely biological approach is not necessarily the most accurate method to adopt.

Sign in / Sign up

Export Citation Format

Share Document