The Winter Snow Cover of the West Antarctic Pack Ice: Its Spatial and Temporal Variability

2013 ◽  
pp. 1-18 ◽  
Author(s):  
Matthew Sturm ◽  
Kim Morris ◽  
Robert Massom
Keyword(s):  
Snow Cover ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
The West ◽  
West Antarctic ◽  
Winter Snow ◽  
Pack Ice

scholarly journals Variability and past long-term changes of brominated very short-lived substances at the tropical tropopause

2020 ◽  
Vol 20 (11) ◽  
pp. 7103-7123
Author(s):  
Susann Tegtmeier ◽  
Elliot Atlas ◽  
Birgit Quack ◽  
Franziska Ziska ◽  
Kirstin Krüger
Keyword(s):  
Central America ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Positive Trend ◽  
The West ◽  
West Pacific ◽  
Mixing Ratios ◽  
Long Term Changes ◽  
Averaged Model

Abstract. Halogenated very short-lived substances (VSLSs), such as bromoform (CHBr3), can be transported to the stratosphere and contribute to the halogen loading and ozone depletion. Given their highly variable emission rates and their short atmospheric lifetimes, the exact amount as well as the spatio-temporal variability of their contribution to the stratospheric halogen loading are still uncertain. We combine observational data sets with Lagrangian atmospheric modelling in order to analyse the spatial and temporal variability of the CHBr3 injection into the stratosphere for the time period 1979–2013. Regional maxima with mixing ratios of up to 0.4–0.5 ppt at 17 km altitude are diagnosed to be over Central America (1) and over the Maritime Continent–west Pacific (2), both of which are confirmed by high-altitude aircraft campaigns. The CHBr3 maximum over Central America is caused by the co-occurrence of convectively driven short transport timescales and strong regional sources, which in conjunction drive the seasonality of CHBr3 injection. Model results at a daily resolution reveal isolated, exceptionally high CHBr3 values in this region which are confirmed by aircraft measurements during the ACCENT campaign and do not occur in spatially or temporally averaged model fields. CHBr3 injection over the west Pacific is centred south of the Equator due to strong oceanic sources underneath prescribed by the here-applied bottom-up emission inventory. The globally largest CHBr3 mixing ratios at the cold point level of up to 0.6 ppt are diagnosed to occur over the region of India, Bay of Bengal, and Arabian Sea (3); however, no data from aircraft campaigns are available to confirm this finding. Inter-annual variability of stratospheric CHBr3 injection of 10 %–20 % is to a large part driven by the variability of coupled ocean–atmosphere circulation systems. Long-term changes, on the other hand, correlate with the regional sea surface temperature trends resulting in positive trends of stratospheric CHBr3 injection over the west Pacific and Asian monsoon region and negative trends over the east Pacific. For the tropical mean, these opposite regional trends balance each other out, resulting in a relatively weak positive trend of 0.017±0.012 ppt Br per decade for 1979–2013, corresponding to 3 % Br per decade. The overall contribution of CHBr3 together with CH2Br2 to the stratospheric halogen loading accounts for 4.7 ppt Br, in good agreement with existing studies, with 50 % and 50 % being injected in the form of source and product gases, respectively.

scholarly journals Spatial and temporal variability of snow depth and ablation rates in a small mountain catchment

2010 ◽  
Vol 4 (2) ◽  
pp. 215-225 ◽  
Author(s):  
T. Grünewald ◽  
M. Schirmer ◽  
R. Mott ◽  
M. Lehning
Keyword(s):  
Snow Cover ◽  
Temporal Variability ◽  
Snow Depth ◽  
Energy Transport ◽  
Snow Water Equivalent ◽  
Laser Scanner ◽  
Ablation Rate ◽  
Spatial And Temporal Variability ◽  
M Cell ◽  
Snow Water

Abstract. The spatio-temporal variability of the mountain snow cover determines the avalanche danger, snow water storage, permafrost distribution and the local distribution of fauna and flora. Using a new type of terrestrial laser scanner, which is particularly suited for measurements of snow covered surfaces, snow depth was monitored in a high alpine catchment during an ablation period. From these measurements snow water equivalents and ablation rates were calculated. This allowed us for the first time to obtain a high resolution (2.5 m cell size) picture of spatial variability of the snow cover and its temporal development. A very high variability of the snow cover with snow depths between 0–9 m at the end of the accumulation season was observed. This variability decreased during the ablation phase, while the dominant snow deposition features remained intact. The average daily ablation rate was between 15 mm/d snow water equivalent at the beginning of the ablation period and 30 mm/d at the end. The spatial variation of ablation rates increased during the ablation season and could not be explained in a simple manner by geographical or meteorological parameters, which suggests significant lateral energy fluxes contributing to observed melt. It is qualitatively shown that the effect of the lateral energy transport must increase as the fraction of snow free surfaces increases during the ablation period.

scholarly journals Spatio-temporal heterogeneity of the snow cover from data of the penetrometer SnowMicroPen

2018 ◽  
Vol 58 (4) ◽  
pp. 473-485
Author(s):  
A. Y. Komarov ◽  
Y. G. Seliverstov ◽  
P. B. Grebennikov ◽  
S. A. Sokratov
Keyword(s):  
Snow Cover ◽  
Temporal Variability ◽  
Climatic Conditions ◽  
Spatial And Temporal Variability ◽  
State University ◽  
Direct Data ◽  
Homogeneous Area ◽  
Spatio Temporal ◽  
University City ◽  
Moscow State University

Te paper presents the results of studies aimed at investigation of the spatial and temporal variability of snow coverstructure on the basis of strength values and its variations obtained by means of the high-resolution penetrometer SnowMicroPen. Te possibilities of fast and independent from the observer identifcation of layers (including identifcation of weakened, potentially avalanche-dangerous layers) were estimated under the climatic conditions of Moscow and the Khibiny mountains. Horizontal areas with homogeneous underlying surface and vegetation were selected for the stratigraphic studies that made it possible to avoid a possible influence of slope relief and exposure from the obtained data on the spatial and temporal variability of the snow depth structure. Te analysis of the information obtained in winter seasons 2014/15 and 2016/17 allowed constructing detailed schemes of the snow cover evolution at the Moscow site as well as assessing the inter-annual and intra-seasonal variability of its structure. Afer the SnowMicroPen data were recorded in the course of the feld works carried out in winter 2015/16 on the Khibiny educational and scientifc base of the Lomonosov Moscow State University (city of Kirovsk), the 10-meter trench on the same profle was described in details, and direct data on the snow cover structure were obtained. Te strength values resulted from the above studies characterize the layers composed of crystals of various shapes and sizes, and they are considered as the frst step to methodology of operational defnition of the spatially-inhomogeneous stratigraphy and stability of snowpack without snowpit observations. Te data analysis showed high spatial and temporal variability of the structure and properties of snow cover even at a homogeneous area, usually described by a single snowpit.

scholarly journals Spatial–Temporal Variability of Snow Cover and Depth in the Qinghai–Tibetan Plateau

2017 ◽  
Vol 30 (4) ◽  
pp. 1521-1533 ◽  
Author(s):  
Wenfang Xu ◽  
Lijuan Ma ◽  
Minna Ma ◽  
Haicheng Zhang ◽  
Wenping Yuan
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Snow Cover ◽  
Temporal Variability ◽  
Snow Depth ◽  
Initial Increase ◽  
Spatial And Temporal Variability ◽  
Important Challenge ◽  
In Situ Observations

Abstract Changes in snow cover over the Qinghai–Tibetan Plateau have attracted much attention in recent years owing to climate change. Because of the limitations of in situ observations, only a few studies have analyzed the dynamics of snow cover. Using observations from 103 meteorological stations across the Qinghai–Tibetan Plateau, this study investigated the spatial and temporal variability of snow depth and the number of snow-cover days. The results show a very weak negative trend for the snow depth and the number of snow-cover days in spring and winter from 1961 to 2010, but two different trends were found: an initial increase followed by a decrease. In summer and autumn, snow depth and the number of snow-cover days show a significant decreasing trend for most sites. The duration of snow cover exhibits a significant decreasing trend (−3.5 ± 1.2 days decade−1), which was jointly controlled by a later snow starting time (1.6 ± 0.8 days decade−1) and an earlier snow ending time (−1.9 ± 0.8 days decade−1) consistent with a response to climate change. This study highlights the competing effects of rising temperatures and changing precipitation, which remain an important challenge in understanding and interpreting the observed changes in snow depth and the number of snow-cover days for the Qinghai–Tibetan Plateau.

scholarly journals Depositional environment of the snow cover on West Antarctic pack-ice floes

1994 ◽  
Vol 20 ◽  
pp. 33-38 ◽  
Author(s):  
M.O. Jeffries ◽  
A.L. Veazey ◽  
K. Morris ◽  
H.R. Krouse
Keyword(s):  
Snow Cover ◽  
Sea Water ◽  
Austral Summer ◽  
Water Flooding ◽  
First Year ◽  
West Antarctic ◽  
Pack Ice ◽  
Bellingshausen Sea ◽  
Density Values ◽  
Ice Floes

The depth, density, load and isotopic (δ18O) composition of the snow cover on pack-ice floes were measured in late austral summer 1992 in the eastern Ross, Amundsen and western Bellingshausen Seas. Snow-density values commonly exceeded 350 kg m-3 and some were as high as 500 kg m-3. The densification of the snow occurs quickly and is attributed to a windy environment. The high density and sometimes considerable depth of the snow on the floes accounts for loads of as much as 700 kg m-2 and resultant sea-water flooding of the underlying sea ice. Lower mean δ18O values in the Ross/Amundsen Seas snow cover suggest that the region might have a cooler climate than the Bellingshausen Sea region. Snow depths on floes in the Bellingshausen Sea region were lower than those in the Ross/Amundsen Seas region, because the Bellingshausen Sea floes were first-year ice. Possible annual units in the isotope profiles of snow, as much as 2m deep, indicate that floes in the Ross/Amundsen Seas region were 2-3 years old.

scholarly journals Connecting European snow cover variability with large scale atmospheric patterns

2010 ◽  
Vol 26 ◽  
pp. 93-97 ◽  
Author(s):  
E. Bartolini ◽  
P. Claps ◽  
P. D'Odorico
Keyword(s):  
Climate Variability ◽  
Snow Cover ◽  
Temporal Variability ◽  
Large Scale ◽  
Management Strategies ◽  
The Other ◽  
The Arctic ◽  
Spatial And Temporal Variability ◽  
East Atlantic ◽  
The North

Abstract. Winter snowfall and its temporal variability are important factors in the development of water management strategies for snow-dominated regions. For example, mountain regions of Europe rely on snow for recreation, and on snowmelt for water supply and hydropower. It is still unclear whether in these regions the snow regime is undergoing any major significant change. Moreover, snow interannual variability depends on different climatic variables, such as precipitation and temperature, and their interplay with atmospheric and pressure conditions. This paper uses the EASE Grid weekly snow cover and Ice Extent database from the National Snow and Ice Data Center to assess the possible existence of trends in snow cover across Europe. This database provides a representation of snow cover fields in Europe for the period 1972–2006 and is used here to construct snow cover indices, both in time and space. These indices allow us to investigate the historical spatial and temporal variability of European snow cover fields, and to relate them to the modes of climate variability that are known to affect the European climate. We find that both the spatial and temporal variability of snow cover are strongly related to the Arctic Oscillation during wintertime. In the other seasons, weaker correlation appears between snow cover and the other patterns of climate variability, such as the East Atlantic, the East Atlantic West Russia, the North Atlantic Oscillation, the Polar Pattern and the Scandinavian Pattern.

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