scholarly journals Hydrologic response to extreme warm and cold summers in the McMurdo Dry Valleys, East Antarctica

2008 ◽  
Vol 20 (5) ◽  
pp. 499-509 ◽  
Author(s):  
Peter T. Doran ◽  
Christopher P. McKay ◽  
Andrew G. Fountain ◽  
Thomas Nylen ◽  
Diane M. McKnight ◽  
...  
Keyword(s):  
Lake Level ◽  
Ross Sea ◽  
Ice Core ◽  
Fold Increase ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Hydrological Response ◽  
Sea Level Pressure ◽  
Significant Difference ◽  
Warm Summer

AbstractThe meteorological characteristics and hydrological response of an extreme warm, and cold summer in the McMurdo Dry Valleys are compared. The driver behind the warmer summer conditions was the occurrence of down-valley winds, which were not present during the colder summer. Occurrence of the summer down-valley winds coincided with lower than typical mean sea level pressure in the Ross Sea region. There was no significant difference in the amount of solar radiation received during the two summers. Compared to the cold summer, glaciological and hydrological response to the warm summer in Taylor Valley included significant glacier mass loss, and 3- to nearly 6000-fold increase in annual streamflow. Lake levels decreased slightly during the cold summer, and increased between 0.54 and 1.01 m during the warm summer, effectively erasing the prior 14 years of lake level lowering in a period of three months. Lake level rise during the warm summer was shown to be strongly associated with and increase in degree days above freezing at higher elevations. We suggest that strong summer down-valley winds may have been responsible for the generation of large glacial lakes during the Last Glacial Maximum when ice core records recorded annual temperatures significantly colder than present.

Climate and Hydrologic Variations and Implications for Lake and Stream Ecological Response in the McMurdo Dry Valleys, Antarctica

2003 ◽  
Author(s):  
Kathleen A. Welch ◽  
W. Berry Lyons
Keyword(s):  
New Zealand ◽  
Climatic Change ◽  
High Latitude ◽  
Lake Level ◽  
Climate Changes ◽  
Global Climate ◽  
Mcmurdo Dry Valleys ◽  
Polar Regions ◽  
Dry Valleys ◽  
Long Term Ecological Research

Because polar regions may amplify what would be considered small to moderate climate changes at lower latitudes, Weller (1998) proposed that the monitoring of high latitude regions should yield early evidence of global climate change. In addition to the climate changes themselves, the connections between the polar regions and the lower latitudes have recently become of great interest to meteorologists and paleoclimatologists alike. In the southern polar regions, the direct monitoring of important climatic variables has taken place only for the last few decades, largely because of their remoteness. This of course limits the extent to which polar records can be related to low latitude records, even at multiyear to decadal timescales. Climatologists and ecologists are faced with the problem that, even though these high latitude regions may provide important clues to global climatic change, the lengths of available records are relatively short. The McMurdo Dry Valleys Long-Term Ecological Research (MCM LTER) program was established in 1993. This program built on the monitoring begun in the late 1960s by researchers from New Zealand, who collected records of climate, lake level, and stream discharge in the Wright Valley, Antarctica. Griffith Taylor’s field party obtained the first data related to lake level in 1903 as part of Scott’s Discovery expedition. Analysis of the more recent data from the New Zealand Antarctic and MCM LTER programs when compared to the 1903 datum indicates that the first half of the twentieth century was a period of steadily increasing streamflows, followed in the last half of the century by streamflows that have resulted in more slowly increasing or stable lake levels (Bomblies et al. 2001). Thus, meteorological and hydrological records generated by the MCM LTER research team, when coupled with past data and the ecological information currently being obtained, provide the first detailed attempt to understand the connection between ecosystem structure and function and climatic change in this region of Antarctica. In addition, the program helps to fill an important gap in the overall understanding of climatic variability in Antarctica.

scholarly journals Helicopter-borne transient electromagnetics in high-latitude environments: An application in the McMurdo Dry Valleys, Antarctica

Geophysics ◽  
2016 ◽  
Vol 81 (1) ◽  
pp. WA87-WA99 ◽  
Author(s):  
Neil Foley ◽  
Slawek Tulaczyk ◽  
Esben Auken ◽  
Cyril Schamper ◽  
Hilary Dugan ◽  
...  
Keyword(s):  
Liquid Water ◽  
Ross Sea ◽  
Mcmurdo Dry Valleys ◽  
Subsurface Water ◽  
Dry Valleys ◽  
Depth Of Penetration ◽  
Temporary Streams ◽  
Low Resistivity ◽  
Subsurface Environments ◽  
Ideal Tool

The McMurdo Dry Valleys are a polar desert in coastal Antarctica, where glaciers, permafrost, ice-covered lakes, and ephemeral summer streams coexist. Liquid water is found at the surface only in lakes and in the temporary streams that feed them. Past geophysical exploration has yielded ambiguous results regarding the presence of subsurface water. In 2011, we used a helicopter-borne, time-domain electromagnetic (TDEM) sensor to map resistivity in the subsurface across the Dry Valleys. The airborne electromagnetic (AEM) method excels at finding subsurface liquid water in polar deserts, where water remains liquid under cold conditions if it is sufficiently saline, and therefore electrically conductive. Over the course of 26 h of helicopter time, we covered large portions of the Dry Valleys and vastly increased our geophysical understanding of the subsurface, particularly with respect to water. Our data show extensive subsurface low-resistivity layers approximately 150–250 m below the surface and beneath higher resistivity layers. We interpret the low-resistivity layers as geologic materials containing freeze-concentrated or “cryoconcentrated” hyper saline brines lying beneath glaciers and frozen permafrost. These brines appeared to be contiguous with surface lakes, subglacial regions, and the Ross Sea, which could indicate a regional-hydrogeologic system, wherein solutes might be transported between surface reservoirs by ionic diffusion and subsurface flow. The presence of such brines underneath glaciers might have implications for glacier movement. Systems such as this, where brines exist beneath glacial ice and frozen permafrost, may exist elsewhere in coastal Antarctica; AEM resistivity is an ideal tool to find and survey them. Our application of TDEM demonstrates that in polar subsurface environments containing conductive brines, such a diffusive electromagnetic method is superior to radar surveying in terms of depth of penetration and ability to differentiate hydrogeologic conditions.

Evidence for regional climate change in the recent evolution of a high latitude pro-glacial lake

1996 ◽  
Vol 8 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Jenny Webster ◽  
Ian Hawes ◽  
Malcolm Downes ◽  
Michael Timperley ◽  
Clive Howard-Williams
Keyword(s):  
Mixed Layer ◽  
Lake Level ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Physical Structure ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
The North ◽  
Victoria Land ◽  
Upper Mixed Layer

Lake Wilson, a perennially ice-capped, deep (>100 m) lake at 80°S in southern Victoria Land was investigated in January 1993. Water chemistry and physical structure showed three distinct layers; an upper c. 35 m mixed layer of low salinity, moderately turbid water; a less turbid mid layer, 20 m thick of slightly higher salinity and supersaturated with oxygen; and a deep 20 m brackish layer (conductivity c. 4000 μS cm−1) with anoxic conditions in the lower 5 m. Extreme supersaturation of N2O (up to 400 times air saturation) together with high nitrate concentration (4000 mg m−3) was recorded in the deep layer. Phytoplankton biomass and photosynthetic activity was confined to the upper mixed layer and the band of supersaturated dissolved oxygen located at 40–55 m appears to represent a relict layer from when the lake level was lower. The evidence from a comparison of profiles between 1975 and 1993 suggests that Lake Wilson has risen 25 m since 1975, synchronous with a period of lake level rise in the McMurdo Dry Valleys lakes to the north at 77°S. Geochemical diffusion models indicate that Lake Wilson had evaporated to a smaller brine lake about 1000 yrs BP, which also fits the pattern shown by the McMurdo Dry Valleys lakes. Climate changes influencing lake levels have thus covered a wide area of southern Victoria Land.

scholarly journals Thermal legacy of a large paleolake in Taylor Valley, East Antarctica as evidenced by an airborne electromagnetic survey

2020 ◽  
Author(s):  
Krista F. Myers ◽  
Peter T. Doran ◽  
Slawek M. Tulaczyk ◽  
Neil T. Foley ◽  
Thue S. Bording ◽  
...  
Keyword(s):  
Lake Level ◽  
Ice Core ◽  
Dry Valleys ◽  
Lake Levels ◽  
Lake Chemistry ◽  
Ice Core Record ◽  
Lake Fryxell ◽  
Lake Drainage ◽  
Airborne Electromagnetic Survey ◽  
Lake Level History

Abstract. Previous studies of the lakes of the McMurdo Dry Valleys have attempted to constrain lake level history, and results suggest the lakes have undergone hundreds of meters of lake level change within the last 20,000 years. Past studies have utilized the interpretation of geologic deposits, lake chemistry, and ice sheet history to deduce lake level history, however a substantial amount of disagreement remains between the findings, indicating a need for further investigation using new techniques. This study utilizes a regional airborne resistivity survey to provide novel insight into the paleohydrology of the region. Mean resistivity maps revealed an extensive brine beneath the Lake Fryxell basin which is interpreted as a legacy groundwater signal from higher lake levels in the past. Resistivity data suggests that active permafrost formation has been ongoing since the onset of lake drainage, and that as recently as 1,000–1,500 yr BP, lake levels were over 60 m higher than present. This coincides with a warmer than modern paleoclimate throughout the Holocene inferred by the nearby Taylor Dome ice core record. Our results indicate mid to late Holocene lake level high stands which runs counter to previous research finding a colder and drier era with little hydrologic activity throughout the last 5,000 years.

scholarly journals Foehn Winds in the McMurdo Dry Valleys, Antarctica: The Origin of Extreme Warming Events*

2010 ◽  
Vol 23 (13) ◽  
pp. 3577-3598 ◽  
Author(s):  
Johanna C. Speirs ◽  
Daniel F. Steinhoff ◽  
Hamish A. McGowan ◽  
David H. Bromwich ◽  
Andrew J. Monaghan
Keyword(s):  
Ross Sea ◽  
Mcmurdo Dry Valleys ◽  
Dry Valleys ◽  
Pressure Gradients ◽  
Synoptic Scale ◽  
Mountain Wave ◽  
Mountain Ranges ◽  
Surface Weather ◽  
Weather Stations ◽  
The Antarctic

Abstract Foehn winds resulting from topographic modification of airflow in the lee of mountain barriers are frequently experienced in the McMurdo Dry Valleys (MDVs) of Antarctica. Strong foehn winds in the MDVs cause dramatic warming at onset and have significant effects on landscape forming processes; however, no detailed scientific investigation of foehn in the MDVs has been conducted. As a result, they are often misinterpreted as adiabatically warmed katabatic winds draining from the polar plateau. Herein observations from surface weather stations and numerical model output from the Antarctic Mesoscale Prediction System (AMPS) during foehn events in the MDVs are presented. Results show that foehn winds in the MDVs are caused by topographic modification of south-southwesterly airflow, which is channeled into the valleys from higher levels. Modeling of a winter foehn event identifies mountain wave activity similar to that associated with midlatitude foehn winds. These events are found to be caused by strong pressure gradients over the mountain ranges of the MDVs related to synoptic-scale cyclones positioned off the coast of Marie Byrd Land. Analysis of meteorological records for 2006 and 2007 finds an increase of 10% in the frequency of foehn events in 2007 compared to 2006, which corresponds to stronger pressure gradients in the Ross Sea region. It is postulated that the intra- and interannual frequency and intensity of foehn events in the MDVs may therefore vary in response to the position and frequency of cyclones in the Ross Sea region.

scholarly journals Solar forcing recorded by aerosol concentrations in coastal

2005 ◽  
Vol 41 ◽  
pp. 52-56 ◽  
Author(s):  
Nancy A.N. Bertler ◽  
Paul A. Mayewski ◽  
Sharon B. Sneed ◽  
Tim R. Naish ◽  
Uwe Morgenstern ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Irradiance ◽  
Ross Sea ◽  
Ice Core ◽  
Ice Sheet ◽  
Aerosol Deposition ◽  
Climate System ◽  
Dry Valleys ◽  
Mass Source ◽  
Air Mass

AbstractIce-core chemistry data from Victoria Lower Glacier, Antarctica, suggest, at least for the last 50 years, a direct influence of solar activity variations on the McMurdo Dry Valleys (MDV) climate system via controls on air-mass input from two competing environments: the East Antarctic ice sheet and the Ross Sea. During periods of increased solar activity, when total solar irradiance is relatively high, the MDV climate system appears to be dominated by air masses originating from the Ross Sea, leading to higher aerosol deposition. During reduced solar activity, the Antarctic interior seems to be the dominant air-mass source, leading to lower aerosol concentration in the ice-core record. We propose that the sensitivity of the MDV to variations in solar irradiance is caused by strong albedo differences between the ice-free MDV and the ice sheet.

scholarly journals Thermal legacy of a large paleolake in Taylor Valley, East Antarctica, as evidenced by an airborne electromagnetic survey

2021 ◽  
Vol 15 (8) ◽  
pp. 3577-3593
Author(s):  
Krista F. Myers ◽  
Peter T. Doran ◽  
Slawek M. Tulaczyk ◽  
Neil T. Foley ◽  
Thue S. Bording ◽  
...  
Keyword(s):  
Lake Level ◽  
Ice Core ◽  
Dry Valleys ◽  
Lake Levels ◽  
Lake Chemistry ◽  
Ice Core Record ◽  
Lake Fryxell ◽  
Lake Drainage ◽  
Airborne Electromagnetic Survey ◽  
Lake Level History

Abstract. Previous studies of the lakes of the McMurdo Dry Valleys have attempted to constrain lake level history, and results suggest the lakes have undergone hundreds of meters of lake level change within the last 20 000 years. Past studies have utilized the interpretation of geologic deposits, lake chemistry, and ice sheet history to deduce lake level history; however a substantial amount of disagreement remains between the findings, indicating a need for further investigation using new techniques. This study utilizes a regional airborne resistivity survey to provide novel insight into the paleohydrology of the region. Mean resistivity maps revealed an extensive brine beneath the Lake Fryxell basin, which is interpreted as a legacy groundwater signal from higher lake levels in the past. Resistivity data suggest that active permafrost formation has been ongoing since the onset of lake drainage and that as recently as 1500–4000 years BP, lake levels were over 60 m higher than present. This coincides with a warmer-than-modern paleoclimate throughout the Holocene inferred by the nearby Taylor Dome ice core record. Our results indicate Mid to Late Holocene lake level high stands, which runs counter to previous research finding a colder and drier era with little hydrologic activity throughout the last 5000 years.

scholarly journals Monsoonal circulation of the McMurdo Dry Valleys, Ross Sea region, Antarctica: signal from the snow chemistry

2004 ◽  
Vol 39 ◽  
pp. 139-145 ◽  
Author(s):  
Nancy A. N. Bertler ◽  
Paul A. Mayewski ◽  
Peter J. Barrett ◽  
Sharon B. Sneed ◽  
Michael J. Handley ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Climate Model ◽  
Ross Sea ◽  
Function Analysis ◽  
Mcmurdo Dry Valleys ◽  
Ion Concentration ◽  
Dry Valleys ◽  
Air Mass ◽  
Snow Chemistry ◽  
Extreme Seasonality

AbstractMcMurdo Dry Valleys (MDV; Ross Sea region, Antarctica) precipitation exhibits extreme seasonality in ion concentration, 3–5 orders of magnitude between summer and winter precipitation. To identify aerosol sources and investigate causes for the observed amplitude in concentration variability, four snow pits were sampled along a coast–Polar Plateau transect across the MDV. The elevation of the sites ranges from 50 to 2400 m and the distance from the coast from 8 to 93 km. Average chemistry gradients along the transect indicate that most species have either a predominant marine or terrestrial source in the MDV. Empirical orthogonal function analysis on the snow-chemistry time series shows that at least 57% of aerosol deposition occurs concurrently. A conceptual climate model, based on meteorological observations, is used to explain the strong seasonality in the MDV. Our results suggest that radiative forcing of the ice-free valleys creates a surface low-pressure cell during summer which promotes air-mass flow from the Ross Sea. The associated precipitating air mass is relatively warm, humid and contains a high concentration of aerosols. During winter, the MDV are dominated by air masses draining off the East Antarctic ice sheet, that are characterized by cold, dry and low concentrations of aerosols. The strong differences between these two air-mass sources create in the MDV a polar version of the monsoonal flow, with humid, warm summers and dry, cold winters.

scholarly journals The influence of föhn winds on Glacial Lake Washburn and palaeotemperatures in the McMurdo Dry Valleys, Antarctica, during the Last Glacial Maximum

2017 ◽  
Vol 29 (5) ◽  
pp. 457-467 ◽  
Author(s):  
M.K. Obryk ◽  
P.T. Doran ◽  
E.D. Waddington ◽  
C.P. Mckay
Keyword(s):  
Last Glacial Maximum ◽  
Ice Core ◽  
Glacial Maximum ◽  
Mcmurdo Dry Valleys ◽  
Glacial Lake ◽  
Dry Valleys ◽  
Glacial Lakes ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractLarge glacial lakes, including Glacial Lake Washburn, were present in the McMurdo Dry Valleys, Antarctica, during the Last Glacial Maximum (LGM) despite a colder and drier climate. To address the mechanism capable of generating enough meltwater to sustain these large lakes, a conceptual model was developed based on the warming potential of infrequent contemporary föhn winds. The model suggests that föhn winds were capable of generating enough meltwater to sustain large glacial lakes during the LGM by increasing degree days above freezing (DDAF) and prolonging the melt season. A present-day relationship between infrequent summer föhn winds and DDAF was established. It is assumed that the Taylor Dome ice core record represents large-scale palaeoclimatic variations for the McMurdo Dry Valleys region. This analysis suggests that because of the warming influence of the more frequent föhn winds, summer DDAF in the McMurdo Dry Valleys during the LGM were equivalent to present-day values, but this enhanced summer signal is not preserved in the annually averaged ice core temperature record.

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