A revised inventory of Antarctic subglacial lakes

Abstract

Abstract:The locations and details of 145 Antarctic subglacial lakes are presented. The inventory is based on a former catalogue of lake-type features, which has been subsequently reanalysed, and on the results from three additional datasets. The first is from Italian radio-echo sounding (RES) of the Dome C region of East Antarctica, from which 14 new lakes are identified. These data also show that, in a number of occasions, multiple lake-type reflectors thought previously to be individual lakes are in fact reflections from the same relatively large lake. This reduces the former total of lake-type reflectors by six, but also adds a significant level of information to these particular lakes. The second dataset is from a Russian survey of the Dome A and Dome F regions of East Antarctica, which provides evidence of 18 new lakes and extends the coverage of the inventory considerably. The third dataset comprises three airborne RES surveys undertaken by the US in East Antarctica over the last five years, from which forty three new lakes have been identified. Reference to information on Lake Vostok, from Italian and US surveys taken in the last few years, is now included.

Radar‐based subglacial lake classification in Antarctica

“…Systematic classification was limited to comparing the best estimate of geothermal flux around an identified lake with the minimum geothermal flux necessary to sustain liquid water given the conditions of the overlying ice [Siegert, 2000]. While radar profiles were preserved on photographic film, these techniques were the most effective way of locating and characterizing subglacial lakes [Oswald and Robin, 1973;Siegert et al, 1996]. Given the vast quantities of radar data being produced and the multiplicity of people working on interpreting these data, it is essential to develop a readily applicable automated algorithm that is capable of locating subglacial lakes in a consistent manner, so as to both verify identification and assist interpretation.…”

“…Additional stacking of 2048 of these digitized signals resulted in a record about [13] Our lake detection and classification strategy defines potential lake candidates as any continuous basal reflection of 500 m or more over which water, if present, would be in hydrostatic equilibrium, given the assumed overburden pressure and elevation. The minimum length serves both to ensure that a representative number of radar observations are included and to maintain consistency with previous lake inventories [Siegert et al, 2005a]. The surface slope over such a feature will always be À1/11 the basal slope.…”

“…We do, however, treat these features as a significant finding. As a result of the low echo strengths, dim lakes are underrepresented in the UTIG contribution to the most recent subglacial lake inventory [Siegert et al, 2005a].…”

“…[2] The locations and approximate dimensions of 145 subglacial lakes in Antarctica have now been published in the literature [Siegert et al, 2005a]. These lakes represent environments where the geothermal heat and the insulation of the overlying ice cover are sufficient to maintain a basal temperature at the pressure melting point of ice.…”

Radar Systems for Glaciology

“…During the last ten years the characteristics of these subglacial lakes have been thoroughly investigated by means of geophysical instruments. Today we know that more than 150 lakes exist beneath (3 km) the Antarctic ice sheets (Siegert et al 2005). They are mainly located beneath the main ice divides and the total volume of water stored in these lakes is between 4000 and 12000 km 3 (Dowswell & Siegert, 1999).…”