Adrian J. Fox

An Emperor Penguin Population Estimate: The First Global, Synoptic Survey of a Species from Space

Our aim was to estimate the population of emperor penguins (Aptenodytes fosteri) using a single synoptic survey. We examined the whole continental coastline of Antarctica using a combination of medium resolution and Very High Resolution (VHR) satellite imagery to identify emperor penguin colony locations. Where colonies were identified, VHR imagery was obtained in the 2009 breeding season. The remotely-sensed images were then analysed using a supervised classification method to separate penguins from snow, shadow and guano. Actual counts of penguins from eleven ground truthing sites were used to convert these classified areas into numbers of penguins using a robust regression algorithm. We found four new colonies and confirmed the location of three previously suspected sites giving a total number of emperor penguin breeding colonies of 46. We estimated the breeding population of emperor penguins at each colony during 2009 and provide a population estimate of ∼238,000 breeding pairs (compared with the last previously published count of 135,000–175,000 pairs). Based on published values of the relationship between breeders and non-breeders, this translates to a total population of ∼595,000 adult birds. There is a growing consensus in the literature that global and regional emperor penguin populations will be affected by changing climate, a driver thought to be critical to their future survival. However, a complete understanding is severely limited by the lack of detailed knowledge about much of their ecology, and importantly a poor understanding of their total breeding population. To address the second of these issues, our work now provides a comprehensive estimate of the total breeding population that can be used in future population models and will provide a baseline for long-term research.

Measured properties of the Antarctic ice sheet derived from the SCAR Antarctic digital database

The completion of the SCAR Antarctic digital database (ADD) has provided a new basis for statistical calculations for Antarctica: data-sets are available at the scale of the original source material, and generalised to 1:1,000,000, 1:3,000,000, 1:10,000,000, and 1:30,000,000. The new descriptive statistics presented are based on the ADD 1:1,000,000 data-set since this is the largest scale at which source maps provided complete cover of the coastline and ice-free areas. The statistics include the total length and proportions of coastline types and the total area of Antarctica with the proportions of its constituent feature types. The areas of the Ross and Filchner-Ronne ice shelves have also been computed. Whilst the total area of Antarctica has remained static compared with previous studies, the relative proportions of coastline types and constituent feature types within the total area show significant changes. In particular the calculated area of ice-free ground is only approximately one-seventh of that often quoted from previous studies. The changes reported result from improved mapping, reinterpretation of data, and actual changes of coastline.

PHOTOGRAMMETRY AS A RESEARCH TOOL FOR GLACIOLOGY

Using a multidisciplinary project studying surging glaciers in Svalbard as a reference, this paper examines some of the ways in which photogrammetry can be used as a research tool by glaciologists. Photogrammetric compilations of two of the glaciers under study were produced from 1990 aerial photography. Photogrammetry was regarded primarily as a source of digital elevation models in this project, rather than as a cartographic tool. Problems encountered in applying photogrammetry to the arctic terrain are considered and a methodology devised to ameliorate these problems by maximizing the available data is described. The results of the photogrammetric work are presented and difficulties in quantifying the accuracy of the photogrammetric data are examined. Examples of the ways in which the photogrammetrically derived digital data have been used for glaciological analysis and visualization are discussed.

The retreat of Jones ice shelf, antarctic peninsula

In recent decades, several ice shelves along the Antarctic Peninsula have diminished in size as a result of climate warming. Using aerial photographic, satellite and survey data we document a similar retreat of Jones Ice Shelf, which was another small ice shelf on the west coast of the Antarctic Peninsula. This ice shelf was roughly stable between 1947 and 1969, but in the early 1970s it began to retreat and had completely disappeared by early 2003. Jones Ice Shelf has two ice fronts only a few kilometres apart and its retreat provides a unique opportunity to examine how different ice fronts retreat when subjected to similar climate forcing. We mapped the retreat of both the east and west ice fronts of Jones Ice Shelf and found that, although individual episodes of retreat may be related to particularly warm summers, the overall progress of retreat of the two ice fronts has been rather different. This suggests that in this case the course of retreat is controlled by the geometry of the embayment and location of pinning points as well as climatic events.

Geometry change between 1990 and 2003 at Finsterwalderbreen, a Svalbard surge-type glacier, from GPS profiling

Abstract Surface mass-balance and geometry data are key to quantifying the climate response of glaciers, and confidence in data synthesis and model interpretations and forecasts requires data from as wide a range of locations and glacier types as possible. This paper presents measurements of surface elevation change at the Svalbard surge-type glacier Finsterwalderbreen, by comparing a 1990 digital elevation model (DEM) with a surface GPS profile from 2003. The pattern of elevation change is consistent with that previously noted between 1970 and 1990, and reflects the continued quiescent-phase evolution of the glacier, with mass loss in the down-glacier/receiving area of up to –1.25mw.e. a–1, and mass gain in the up-glacier/reservoir area of up to 0.60 mw.e. a–1; the area-weighted, mean change for the whole glacier is 0.19mw.e. a–1. The spatial pattern of elevation increase and decrease is complex, and the boundary between thickening and thinning determined by combining GPS and DEM data does not appear to correspond with the equilibrium-line altitude determined from surface mass-balance measurements. There is no evidence yet of a decrease in the rate of reservoir area build-up driven by mass-balance change resulting from the warmer winter air temperatures, and decreased proportion of snowfall in total precipitation, noted at meteorological stations in Svalbard.

The Antarctic Regional GPS Network Densification: Status and Results

We report on the activities related to the IAG Subcommission 1.3f “Regional Reference Frame for Antarctica”. Campaign-style GPS observations have been carried out since 1995. Based on the Bernese GNSS Software the latest analysis yields results for about 30 stations aligned to the terrestrial reference frame solution IGS08. The obtained station motions are discussed in the context of plate kinematics and glacial-isostatic adjustment. It is demonstrated that the activities are a valuable contribution both to the ITRF densification in Antarctica and to geodynamic research.

Pioneers of Photogrammetry Commemorated In Antarctic Place‐Names

Unique place-names are essential for scientific fieldwork in Antarctica. This shorter contribution describes how duplication of place-names in British Antarctic Territory has been avoided by the systematic naming of geographically related features according to groups of associated ideas. One such theme, commemorating pioneers in the development of photogrammetry, recognizes the important contribution of photogrammetry to Antarctic mapping and research.