scholarly journals Mass and heat balance of snowpatches in Basen nunatak, Dronning Maud Land, Antarctica, in summer

2013 ◽  
Vol 59 (218) ◽  
pp. 1093-1105 ◽  
Author(s):  
Matti Leppäranta ◽  
Onni Järvinen ◽  
Elisa Lindgren
Keyword(s):  
Heat Balance ◽  
Snow Water Equivalent ◽  
Research Programme ◽  
Surface Energy Flux ◽  
Meltwater Runoff ◽  
Dronning Maud Land ◽  
Snow Water ◽  
Antarctic Research ◽  
The Mean ◽  
Snow Thickness

AbstractAn experimental study concerning the mass and heat balance of snowpatches was performed during the Finnish Antarctic Research Programme (FINNARP) 2004 and 2010 summer expeditions to Basen nunatak (73°03′ S, 13°25′ W). Data were collected from a snow stake line, snow pits and automated weather and snow recording systems. One 100 m perennial snowpatch and several smaller seasonal patches (<10 m) were monitored. Snow thickness decreased by 4.0–6.3 mm d−1 due to sublimation, compression and, close to lateral boundaries, meltwater runoff. The vertical mass loss was 1–2 mm snow water equivalent (SWE) d−1 and the lateral decay was −10 cm d−1. The net radiation was 20.2 W m−2 and the mean latent heat flux was −15.5 W m−2 .The mean surface energy flux was 4.9 W m −2 and the heat loss to the ground was 1.5 W m−2. Thin snow decayed faster due to surface thermomechanical erosion and melt from the bottom where the soil was heated by the solar radiation. Between the summers of 2004 and 2010, the thickness of the perennial snowpatch decreased by 230 mm.

scholarly journals Utility of late summer transient snowline migration rate on Taku Glacier, Alaska

2011 ◽  
Vol 5 (4) ◽  
pp. 1127-1133 ◽  
Author(s):  
M. Pelto
Keyword(s):  
Mass Balance ◽  
Migration Rate ◽  
Satellite Images ◽  
Snow Water Equivalent ◽  
Late Summer ◽  
Ablation Rate ◽  
Field Observations ◽  
Balance Assessment ◽  
Snow Water ◽  
The Mean

Abstract. On Taku Glacier, Alaska a combination of field observations of snow water equivalent (SWE) from snowpits and probing in the vicinity of the transient snowline (TSL) are used to quantify the mass balance gradient. The balance gradient derived from the TSL and SWE measured in snowpits at 1000 m from 1998–2010 ranges from 2.6–3.8 mm m−1. Probing transects from 950 m–1100 m directly measure SWE and yield a slightly higher balance gradient of 3.3–3.8 mm m−1. The TSL on Taku Glacier is identified in MODIS and Landsat 4 and 7 Thematic Mapper images for 31 dates during the 2004–2010 period to assess the consistency of its rate of rise and reliability in assessing ablation for mass balance assessment. For example, in 2010, the TSL was 750 m on 28 July, 800 m on 5 August, 875 m on 14 August, 925 m on 30 August, and 975 m on 20 September. The mean observed probing balance gradient was 3.3 mm m−1, combined with the TSL rise of 3.7 m day−1 yields an ablation rate of 12.2 mm day−1 from mid-July to mid-Sept, 2010. The TSL rise in the region from 750–1100 m on Taku Glacier during eleven periods each covering more than 14 days during the ablation season indicates a mean TSL rise of 3.7 m day−1, the rate of rise is relatively consistent ranging from 3.1 to 4.4 m day−1. This rate is useful for ascertaining the final ELA if images or observations are not available near the end of the ablation season. The mean ablation from 750–1100 m during the July–September period determined from the TSL rise and the observed balance gradient is 11–13 mm day−1 on Taku Glacier during the 2004–2010 period. The potential for providing an estimate of bn from TSL observations late in the melt season from satellite images combined with the frequent availability of such images provides a means for efficient mass balance assessment in many years and on many glaciers.

scholarly journals A newly detected ablation phenomena in Dronning Maud Land, Antarctica

1995 ◽  
Vol 165 ◽  
pp. 93-96
Author(s):  
C.E Bøggild ◽  
J.-G Winther
Keyword(s):  
Research Effort ◽  
Research Programme ◽  
Research Interest ◽  
Geological Survey ◽  
Deep Drilling ◽  
Dronning Maud Land ◽  
Antarctic Research ◽  
Antarctic Treaty ◽  
New Research ◽  
Climate Studies

From November 1993 to February 1994 members of the Geological Survey of Greenland (GGU) participated in a Nordic research effort in Antarctica. The Nordic Antarctic Research Programme (NARP) involves Norway, Sweden and Finland, which are all Antarctic Treaty Consultative Partners; Denmark as an observer has participated only since 1992 (Thomsen, 1994; Boggild et al., 1995). The member countries of NARP have traditionally carried out research in Dronning Maud Land. This region of Antarctica has recently gained new research interest, including survey for a joint European deep drilling programme planned for 1995/96. Future Norwegian climate studies on blue ice will therefore be closely related to the joint European deep drilling programme.

scholarly journals Evaluation of Remotely Sensed Snow Water Equivalent and Snow Cover Extent over the Contiguous United States

2018 ◽  
Vol 19 (11) ◽  
pp. 1777-1791 ◽  
Author(s):  
Nicholas Dawson ◽  
Patrick Broxton ◽  
Xubin Zeng
Keyword(s):  
United States ◽  
Remote Sensing ◽  
Snow Cover ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Remote Sensing Data ◽  
Sensing Data ◽  
Snow Cover Extent ◽  
Snow Water ◽  
The Mean

Abstract Global snow water equivalent (SWE) products derived at least in part from satellite remote sensing are widely used in weather, climate, and hydrometeorological studies. Here we evaluate three such products using our recently developed daily 4-km SWE dataset available from October 1981 to September 2017 over the conterminous United States. This SWE dataset is based on gridded precipitation and temperature data and thousands of in situ measurements of SWE and snow depth. It has a 0.98 correlation and 30% relative mean absolute deviation with Airborne Snow Observatory data and effectively bridges the gap between small-scale lidar surveys and large-scale remotely sensed data. We find that SWE products using remote sensing data have large differences (e.g., the mean absolute difference from our SWE data ranges from 45.8% to 59.3% of the mean SWE in our data), especially in forested areas (where this percentage increases up to 73.5%). Furthermore, they consistently underestimate average maximum SWE values and produce worse SWE (including spurious jumps) during snowmelt. Three additional higher-resolution satellite snow cover extent (SCE) products are used to compare the SCE values derived from these SWE products. There is an overall close agreement between these satellite SCE products and SCE generated from our SWE data, providing confidence in our consistent SWE, snow depth, and SCE products based on gridded climate and station data. This agreement is also stronger than that between satellite SCE and those derived from the three satellite SWE products, further confirming the deficiencies of the SWE products that utilize remote sensing data.

Field evaluation of a new method for estimation of liquid water content and snow water equivalent of wet snowpacks with GPR

2012 ◽  
Vol 44 (4) ◽  
pp. 600-613 ◽  
Author(s):  
Nils Sundström ◽  
David Gustafsson ◽  
Andrey Kruglyak ◽  
Angela Lundberg
Keyword(s):  
Water Content ◽  
Liquid Water ◽  
Ground Penetrating Radar ◽  
Snow Water Equivalent ◽  
Field Evaluation ◽  
Liquid Water Content ◽  
Snow Water ◽  
The Mean ◽  
Path Dependent ◽  
Ground Penetrating

Estimates of snow water equivalent (SWE) with ground-penetrating radar can be used to calibrate and validate measurements of SWE over large areas conducted from satellites and aircrafts. However, such radar estimates typically suffer from low accuracy in wet snowpacks due to a built-in assumption of dry snow. To remedy the problem, we suggest determining liquid water content from path-dependent attenuation. We present the results of a field evaluation of this method which demonstrate that, in a wet snowpack between 0.9 and 3 m deep and with about 5 vol% of liquid water, liquid water content is underestimated by about 50% (on average). Nevertheless, the method decreases the mean error in SWE estimates to 16% compared to 34% when the presence of liquid water in snow is ignored and 31% when SWE is determined directly from two-way travel time and calibrated for manually measured snow density.

scholarly journals Improved measurement of ice layer density in seasonal snowpacks

2015 ◽  
Vol 9 (6) ◽  
pp. 5979-6002
Author(s):  
T. Watts ◽  
N. Rutter ◽  
P. Toose ◽  
C. Derksen ◽  
M. Sandells ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Transport Properties ◽  
Snow Water Equivalent ◽  
Canadian Arctic ◽  
Field Method ◽  
Ecological Impacts ◽  
Vapour Transport ◽  
Layer Density ◽  
Snow Water ◽  
The Mean

Abstract. Ice layers in snowpacks introduce uncertainty in satellite derived estimates of snow water equivalent, have ecological impacts on plants and animals, and change the thermal and vapour transport properties of the snowpack. The microstructure and specifically the density of ice layers is poorly quantified. Here we present a new field method, for measuring the density of ice layers caused by melt or rain-on-snow events. The method was used on 87 ice layer samples in the Canadian Arctic and mid-latitudes; the mean measured ice layer density was 909 ± 18 kg m−3 with a standard deviation of 23 kg m−3, significantly higher than values typically used in the literature.

scholarly journals Uncertainty budget in snow thickness and snow water equivalent estimation using GPR and TDR techniques

2016 ◽  
Author(s):  
Federico Di Paolo ◽  
Barbara Cosciotti ◽  
Sebastian E. Lauro ◽  
Elisabetta Mattei ◽  
Mattia Callegari ◽  
...  
Keyword(s):  
Traditional Method ◽  
Snow Water Equivalent ◽  
Uncertainty Budget ◽  
Radar Data ◽  
Complete Analysis ◽  
Fundamental Parameter ◽  
Non Invasive ◽  
Electromagnetic Methods ◽  
Snow Water ◽  
Snow Thickness

Abstract. Snow water equivalent is a fundamental parameter for hydrological and climate change studies but its measurement is usually time consuming and destructive. Electromagnetic methods could be a valid alternative to conventional techniques, being fast and non-invasive. In this work we analyze the reliability of a combined GPR/TDR method to estimate snow thickness and snow water equivalent. To estimate GPR accuracy we perform a calibration test where measured and predicted radar data are compared in terms of two-way travel time. Furthermore we implement a complete analysis of the uncertainty budget in order to evaluate the "weight" of each uncertainty on the snow parameters computation chain. We found that GPR, supported by TDR data, is quite reliable as it measures snow thickness and snow water equivalent with an accuracy comparable to that of a traditional method but, in general, with a slightly larger uncertainty.

scholarly journals Why Do Global Reanalyses and Land Data Assimilation Products Underestimate Snow Water Equivalent?

2016 ◽  
Vol 17 (11) ◽  
pp. 2743-2761 ◽  
Author(s):  
Patrick D. Broxton ◽  
Xubin Zeng ◽  
Nicholas Dawson
Keyword(s):  
High Resolution ◽  
Data Assimilation ◽  
Snow Water Equivalent ◽  
Primary Reason ◽  
Snow Water ◽  
Land Data Assimilation ◽  
Freezing Temperatures ◽  
Data Assimilation System ◽  
Assimilation System ◽  
Snow Thickness

Abstract There is a large uncertainty of snow water equivalent (SWE) in reanalyses and the Global Land Data Assimilation System (GLDAS), but the primary reason for this uncertainty remains unclear. Here several reanalysis products and GLDAS with different land models are evaluated and the primary reason for their deficiencies are identified using two high-resolution SWE datasets, including the Snow Data Assimilation System product and a new dataset for SWE and snowfall for the conterminous United States (CONUS) that is based on PRISM precipitation and temperature data and constrained with thousands of point snow observations of snowfall and snow thickness. The reanalyses and GLDAS products substantially underestimate SWE in the CONUS compared to the high-resolution SWE data. This occurs irrespective of biases in atmospheric forcing information or differences in model resolution. Furthermore, reanalysis and GLDAS products that predict more snow ablation at near-freezing temperatures have larger underestimates of SWE. Since many of the products do not assimilate information about SWE and snow thickness, this indicates a problem with the implementation of land models and pinpoints the need to improve the treatment of snow ablation in these systems, especially at near-freezing temperatures.

scholarly journals Investigations of the Oxygen-18 Content of Samples from Snow Pits and Ice Cores from the Filchner-Ronne Ice Shelves and Ekström Ice Shelf

1985 ◽  
Vol 7 ◽  
pp. 49-53 ◽  
Author(s):  
O. Reinwarth ◽  
W. Graf ◽  
W. Stichler ◽  
H. Moser ◽  
H. Oerter
Keyword(s):  
Accumulation Rate ◽  
Ice Cores ◽  
Research Programme ◽  
Ice Shelf ◽  
Annual Average ◽  
Ice Shelves ◽  
Antarctic Research ◽  
Isotope Studies ◽  
The Mean ◽  
Ice Edge

Since 1979–80, isotope studies with oxygen-18 (18O) have been carried out at several snow pits and ice cores near the German Georg-von-Neumayer station (Ekström ice shelf, Atka Bay), as well as from the Filchner-Ronne ice shelves, in the framework of the German Antarctic research programme. The investigations of snow pits on the Filchner-Ronne ice shelves yield a standard deviation for the annual average δ18O values of approximately 1‰ over the last five years, and a decrease of δ18O with distance from the ice edge of about 1‰ per 50 km. The variation of δ18O for stratigraphically matching snow layers from snow pits at the same location in different years is about 0.3‰ on the Filchner-Ronne ice shelves, and 0.8‰ at Georg-von-Neumayer station. The mean annual accumulation rate in the surroundings of Georg-von-Neumayer station was determined to be 34 g cm-2 for the years 1977–81. On the Filchner-Ronne ice shelves the mean annual accumulation rate (1979–83) decreases from 22 g cm−2 at Filchner station to 15 g cm−2 at traverse point T340, located 200 km southeast of Filchner station.

scholarly journals Investigations of the Oxygen-18 Content of Samples from Snow Pits and Ice Cores from the Filchner-Ronne Ice Shelves and Ekström Ice Shelf

1985 ◽  
Vol 7 ◽  
pp. 49-53 ◽  
Author(s):  
O. Reinwarth ◽  
W. Graf ◽  
W. Stichler ◽  
H. Moser ◽  
H. Oerter
Keyword(s):  
Accumulation Rate ◽  
Ice Cores ◽  
Research Programme ◽  
Ice Shelf ◽  
Annual Average ◽  
Ice Shelves ◽  
Antarctic Research ◽  
Isotope Studies ◽  
The Mean ◽  
Ice Edge

Since 1979–80, isotope studies with oxygen-18 (18O) have been carried out at several snow pits and ice cores near the German Georg-von-Neumayer station (Ekström ice shelf, Atka Bay), as well as from the Filchner-Ronne ice shelves, in the framework of the German Antarctic research programme. The investigations of snow pits on the Filchner-Ronne ice shelves yield a standard deviation for the annual average δ18O values of approximately 1‰ over the last five years, and a decrease of δ18O with distance from the ice edge of about 1‰ per 50 km. The variation of δ18O for stratigraphically matching snow layers from snow pits at the same location in different years is about 0.3‰ on the Filchner-Ronne ice shelves, and 0.8‰ at Georg-von-Neumayer station. The mean annual accumulation rate in the surroundings of Georg-von-Neumayer station was determined to be 34 g cm-2 for the years 1977–81. On the Filchner-Ronne ice shelves the mean annual accumulation rate (1979–83) decreases from 22 g cm−2 at Filchner station to 15 g cm−2 at traverse point T340, located 200 km southeast of Filchner station.

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