scholarly journals Reanalysis of 47 Years of Climate in the French Alps (1958–2005): Climatology and Trends for Snow Cover

2009 ◽  
Vol 48 (12) ◽  
pp. 2487-2512 ◽  
Author(s):  
Yves Durand ◽  
Gérald Giraud ◽  
Martin Laternser ◽  
Pierre Etchevers ◽  
Laurent Mérindol ◽  
...  
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Numerical Models ◽  
High Elevation ◽  
Climatic Conditions ◽  
Spatial And Temporal Variability ◽  
The South ◽  
French Alps ◽  
Mountainous Regions ◽  
The North

Abstract Since the early 1990s, Météo-France has used an automatic system combining three numerical models to simulate meteorological parameters, snow cover stratigraphy, and avalanche risk at various altitudes, aspects, and slopes for a number of mountainous regions (massifs) in the French Alps and the Pyrenees. This Système d’Analyse Fournissant des Renseignements Atmosphériques à la Neige (SAFRAN)–Crocus–Modèle Expert de Prévision du Risque d’Avalanche (MEPRA) model chain (SCM), usually applied to operational daily avalanche forecasting, is here used for retrospective snow and climate analysis. For this study, the SCM chain used both meteorological observations and guess fields mainly issued from the newly reanalyzed atmospheric model 40-yr ECMWF Re-Analysis (ERA-40) data and ran on an hourly basis over a period starting in the winter of 1958/59 until recent past winters. Snow observations were finally used for validation, and the results presented here concern only the main climatic features of the alpine modeled snowfields at different spatial and temporal scales. The main results obtained confirm the very significant spatial and temporal variability of the modeled snowfields with regard to certain key parameters such as those describing ground coverage or snow depth. Snow patterns in the French Alps are characterized by a marked declining gradient from the northwestern foothills to the southeastern interior regions. This applies mainly to both depths and durations, which exhibit a maximal latitudinal variation at 1500 m of about 60 days, decreasing strongly with the altitude. Enhanced at low elevations, snow depth shows a mainly negative temporal variation over the study period, especially in the north and during late winters, while the south exhibits more smoothed features. The number of days with snow on the ground shows also a significant general signal of decrease at low and midelevation, but this signal is weaker in the south than in the north and less visible at high elevation. Even if a statistically significant test cannot be performed for all elevations and areas, the temporal decrease is present in all the studied quantities. Concerning snow duration, this general decrease can also be interpreted as a sharp variation of the mean values at the end of the 1980s, inducing a step effect in its time series rather than a constant negative temporal trend. The results have also been interpreted in terms of potential for a viable ski industry, especially in the southern areas, and for different changing climatic conditions. Presently, French downhill ski resorts are economically viable from a range of about 1200 m MSL in the northern foothills to 2000 m in the south, but future prospects are uncertain. In addition, no clear and direct relationship between the North Atlantic Oscillation (NAO) or the ENSO indexes and the studied snow parameters could be established in this study.

scholarly journals Commentary on comparison of MODIS snow cover and albedo products with ground observations over the mountainous terrain of Turkey

2006 ◽  
Vol 3 (6) ◽  
pp. 3655-3673 ◽  
Author(s):  
A. Ü. Şorman ◽  
Z. Akyürek ◽  
A. Şensoy ◽  
A. A. Şorman ◽  
A. E. Tekeli
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Winter Season ◽  
Spatial And Temporal Variability ◽  
Mountainous Terrain ◽  
Mountainous Regions ◽  
In Situ Data ◽  
Snow Cover Extent

Abstract. The MODerate-resolution Imaging Spectroradiometer (MODIS) snow cover product was evaluated by Parajka and Blösch (2006) over the territory of Austria. The spatial and temporal variability of the MODIS snow product classes are analyzed, the accuracy of the MODIS snow product against numerous in situ snow depth data are examined and the main factors that may influence the MODIS classification accuracy are identified in their studies. The authors of this paper would like to provide more discussion to the scientific community on the "Validation of MODIS snow cover images" when similar methodology is applied to mountainous regions covered with abundant snow but with limited number of ground survey and automated stations. Daily snow cover maps obtained from MODIS images are compared with ground observations in mountainous terrain of Turkey for the winter season of 2002–2003 and 2003–2004 during the accumulation and ablation periods of snow. Snow depth and density values are recorded to determine snow water equivalent values at 19 points in and around the study area in Turkey. Comparison of snow maps with in situ data show good agreement with overall accuracies in between 62 to 82 percent considering a 2-day shift during cloudy days. Studies show that the snow cover extent can be used for forecasting of runoff hydrographs resulting mostly from snowmelt for a mountainous basin in Turkey. MODIS-Terra snow albedo products are also compared with ground based measurements over the ablation stage of 2004 using the automated weather operating stations (AWOS) records at fixed locations as well as from the temporally assessed measuring sites during the passage of the satellite. Temporarily assessed 20 ground measurement sites are randomly distributed around one of the AWOS stations and both MODIS and ground data were aggregated in GIS for analysis. Reduction in albedo is noticed as snow depth decreased and SWE values increased.

scholarly journals Assimilating MODIS and AMSR-E Snow Observations in a Snow Evolution Model

2012 ◽  
Vol 13 (5) ◽  
pp. 1475-1492 ◽  
Author(s):  
Steven J. Fletcher ◽  
Glen E. Liston ◽  
Christopher A. Hiemstra ◽  
Steven D. Miller
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Evolution Model ◽  
The South ◽  
Earth Observing System ◽  
The North ◽  
Moderate Resolution ◽  
Snow Water ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract In this paper four simple computationally inexpensive, direct insertion data assimilation schemes are presented, and evaluated, to assimilate Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover, which is a binary observation, and Advanced Microwave Scanning Radiometer for Earth Observing System (EOS) (AMSR-E) snow water equivalent (SWE) observations, which are at a coarser resolution than MODIS, into a numerical snow evolution model. The four schemes are 1) assimilate MODIS snow cover on its own with an arbitrary 0.01 m added to the model cells if there is a difference in snow cover; 2) iteratively change the model SWE values to match the AMSR-E equivalent value; 3) AMSR-E scheme with MODIS observations constraining which cells can be changed, when both sets of observations are available; and 4) MODIS-only scheme when the AMSR-E observations are not available, otherwise scheme 3. These schemes are used in the winter of 2006/07 over the southeast corner of Colorado and the tri-state area: Wyoming, Colorado, and Nebraska. It is shown that the inclusion of MODIS data enables the model in the north domain to have a 15% improvement in number of days with a less than 10% disagreement with the MODIS observation 24 h later and approximately 5% for the south domain. It is shown that the AMSR-E scheme has more of an impact in the south domain than the north domain. The assimilation results are also compared to station snow-depth data in both domains, where there is up-to-a-factor-of-5 underestimation of snow depth by the assimilation schemes compared with the station data but the snow evolution is fairly consistent.

scholarly journals Recent fluctuation of snow cover on mountainous areas in Japan

2001 ◽  
Vol 32 ◽  
pp. 97-101 ◽  
Author(s):  
Masujiro Shimizu ◽  
Osamu Abe
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Global Solar Radiation ◽  
High Elevation ◽  
Meteorological Conditions ◽  
Mountainous Areas ◽  
The North ◽  
Observation Network ◽  
Snow Conditions ◽  
The Relationship

AbstractTo monitor the snow-cover distribution in relation to meteorological conditions on high mountainous areas in Japan, NIED constructed a snow-observation network which it has operated for approximately 10 years. The network consists of seven pairs of stations, each comprising a mountainous site and a low-lying flatland site, from Hokkaido district in the north to San-in in the southwest. Data obtained include snow depth, snow weight, air temperature and global solar radiation. This study presents recent fluctuation of snow cover on mountainous areas for several recent winters in Japan. Most winters were warmer than average, but winter 1995/96 was normal, and maximum snow depths were recorded in high-elevation areas. Seventy-seven avalanche accidents occurred in winter 1995/96. The relationship between meteorological and snow conditions in mountainous areas and flatland areas was analyzed.

scholarly journals Commentary on comparison of MODIS snow cover and albedo products with ground observations over the mountainous terrain of Turkey

2007 ◽  
Vol 11 (4) ◽  
pp. 1353-1360 ◽  
Author(s):  
A. Ü. Şorman ◽  
Z. Akyürek ◽  
A. Şensoy ◽  
A. A. Şorman ◽  
A. E. Tekeli
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Snow Water Equivalent ◽  
Winter Season ◽  
Spatial And Temporal Variability ◽  
Mountainous Terrain ◽  
Mountainous Regions ◽  
In Situ Data ◽  
Snow Cover Extent

Abstract. The MODerate-resolution Imaging Spectroradiometer (MODIS) snow cover product was evaluated by Parajka and Blösch (2006) over the territory of Austria. The spatial and temporal variability of the MODIS snow product classes are analyzed, the accuracy of the MODIS snow product against numerous in situ snow depth data are examined and the main factors that may influence the MODIS classification accuracy are identified in their studies. The authors of this paper would like to provide more discussion to the scientific community on the "Validation of MODIS snow cover images" when similar methodology is applied to mountainous regions covered with abundant snow but with limited number of ground survey and automated stations. Daily snow cover maps obtained from MODIS images are compared with ground observations in mountainous terrain of Turkey for the winter season of 2002–2003 and 2003–2004 during the accumulation and ablation periods of snow. Snow depth and density values are recorded to determine snow water equivalent (SWE) values at 19 points in and around the study area in Turkey. Comparison of snow maps with in situ data show good agreement with overall accuracies in between 62 to 82 percent considering a 2-day shift during cloudy days. Studies show that the snow cover extent can be used for forecasting of runoff hydrographs resulting mostly from snowmelt for a mountainous basin in Turkey. MODIS-Terra snow albedo products are also compared with ground based measurements over the ablation stage of 2004 using the automated weather operating stations (AWOS) records at fixed locations as well as from the temporally assessed measuring sites during the passage of the satellite. Temporarily assessed 20 ground measurement sites are randomly distributed around one of the AWOS stations and both MODIS and ground data were aggregated in GIS for analysis. Reduction in albedo is noticed as snow depth decreased and SWE values increased.

scholarly journals Rates of consumption of atmospheric CO<sub>2</sub> through the weathering of loess during the next 100 yr of climate change

2013 ◽  
Vol 10 (1) ◽  
pp. 135-148 ◽  
Author(s):  
Y. Goddéris ◽  
S. L. Brantley ◽  
L. M. François ◽  
J. Schott ◽  
D. Pollard ◽  
...  
Keyword(s):  
Climate Change ◽  
Reaction Front ◽  
Numerical Models ◽  
Atmospheric Co2 ◽  
Co2 Production ◽  
Depth Interval ◽  
Mississippi Valley ◽  
The South ◽  
The North ◽  
The Future

Abstract. Quantifying how C fluxes will change in the future is a complex task for models because of the coupling between climate, hydrology, and biogeochemical reactions. Here we investigate how pedogenesis of the Peoria loess, which has been weathering for the last 13 kyr, will respond over the next 100 yr of climate change. Using a cascade of numerical models for climate (ARPEGE), vegetation (CARAIB) and weathering (WITCH), we explore the effect of an increase in CO2 of 315 ppmv (1950) to 700 ppmv (2100 projection). The increasing CO2 results in an increase in temperature along the entire transect. In contrast, drainage increases slightly for a focus pedon in the south but decreases strongly in the north. These two variables largely determine the behavior of weathering. In addition, although CO2 production rate increases in the soils in response to global warming, the rate of diffusion back to the atmosphere also increases, maintaining a roughly constant or even decreasing CO2 concentration in the soil gas phase. Our simulations predict that temperature increasing in the next 100 yr causes the weathering rates of the silicates to increase into the future. In contrast, the weathering rate of dolomite – which consumes most of the CO2 – decreases in both end members (south and north) of the transect due to its retrograde solubility. We thus infer slower rates of advance of the dolomite reaction front into the subsurface, and faster rates of advance of the silicate reaction front. However, additional simulations for 9 pedons located along the north–south transect show that the dolomite weathering advance rate will increase in the central part of the Mississippi Valley, owing to a maximum in the response of vertical drainage to the ongoing climate change. The carbonate reaction front can be likened to a terrestrial lysocline because it represents a depth interval over which carbonate dissolution rates increase drastically. However, in contrast to the lower pH and shallower lysocline expected in the oceans with increasing atmospheric CO2, we predict a deeper lysocline in future soils. Furthermore, in the central Mississippi Valley, soil lysocline deepening accelerates but in the south and north the deepening rate slows. This result illustrates the complex behavior of carbonate weathering facing short term global climate change. Predicting the global response of terrestrial weathering to increased atmospheric CO2 and temperature in the future will mostly depend upon our ability to make precise assessments of which areas of the globe increase or decrease in precipitation and soil drainage.

scholarly journals Specifics of boglands freezing in the north and northwest of the European part of Russia under climate change

2019 ◽  
Vol 59 (2) ◽  
pp. 233-244
Author(s):  
V. I. Batuev ◽  
I. L. Kalyuzhny
Keyword(s):  
Ambient Temperature ◽  
Snow Cover ◽  
Spatial And Temporal Variability ◽  
North West ◽  
The North ◽  
Climatic Period ◽  
European Part Of Russia ◽  
Freezing Depth ◽  
Main Factors ◽  
Cover Thickness

Long-term complex observations covering the period of 1949–2018 made possible to determine the average annual characteristics of the depth of freezing of wetlands in the North and Northwest of the European territory of Russia together with main factors of its formation, and spatial and temporal variability. The main factors that determine the depth of freezing of wetlands are ambient temperature, snow cover thickness, and a degree of watering of the micro landscape (water reserves of the micro landscape). At the initial stage of freezing, the major factor is the ambient temperature, when intensity of the freezing reaches 0.5–0.8 cm/day. As snow falls, the freezing rate becomes smaller, and when the snow cover thickness reaches 25–30 cm the depth amounts to 0.2–0.3 cm/day and smaller. It was found that the spatial variability of the freezing depth decreases from large values of the coefficient of variation (0.3–0.4) at the depth of 20–30 cm to less than 0.1 when the depth exceeds 60 cm. The largest values of the depth are recorded in the North of the Kola Peninsula, where sometimes they reach from 84 to 97 cm with the average values of 48–66. In large hummocky bogs, when the seasonal freezing comes down to 63–65 cm it links with the permafrost layer. On average, swamps of these bogs freeze down to a depth of 68 cm. The average climatic depth of freezing of oligotrophic bogs of the NorthWest is 21–24 cm; in some years, freezing of them reaches 32–40 cm. It has been shown that the relative warming of the climate resulted in decreasing in the depth of freezing of wetlands in the North and North-West of the European territory of Russia. Relative to the previous climatic period, the depth of frost penetration in the northern Ilasskoye bog decreased by 32%, and in north-western Lammin-Suo bog – by 31%.

scholarly journals Validation of MODIS snow cover images over Austria

2006 ◽  
Vol 3 (4) ◽  
pp. 1569-1601 ◽  
Author(s):  
J. Parajka ◽  
G. Blöschl
Keyword(s):  
Snow Cover ◽  
Classification Accuracy ◽  
Snow Depth ◽  
Seasonal Pattern ◽  
Acquisition Time ◽  
Spatial And Temporal Variability ◽  
Temporal Shift ◽  
Early Afternoon ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. This study evaluates the Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover product over the territory of Austria. The aims are (a) to analyse the spatial and temporal variability of the MODIS snow product classes, (b) to examine the accuracy of the MODIS snow product against in situ snow depth data, and (c) to identify the main factors that may influence the MODIS classification accuracy. We use daily MODIS grid maps (version 4) and daily snow depth measurements at 754 climate stations in the period from February 2000 to December 2005. The results indicate that, on average, clouds obscured 63% of Austria, which may significantly restrict the applicability of the MODIS snow cover images to hydrological modelling. On cloud-free days, however, the classification accuracy is very good with an average of 95%. There is no consistent relationship between the classification errors and dominant land cover type and local topographical variability but there are clear seasonal patterns to the errors. In December and January the errors are around 15% while in summer they are less than 1%. This seasonal pattern is related to the overall percentage of snow cover in Austria, although in spring, when there is a well developed snow pack, errors tend to be smaller than they are in early winter for the same overall percent snow cover. Overestimation and underestimation errors balance during most of the year which indicates little bias. In November and December, however, there appears to exist a tendency for overestimation. Part of the errors may be related to the temporal shift between the in situ snow depth measurements (07:00 a.m.) and the MODIS acquisition time (early afternoon).

THE ROLE OF TECHNOGENIC IMPACT IN THE DEVELOPMENT OF DANGEROUS GEOLOGICAL PROCESSES IN THE MOUNTAIN REGIONS OF THE NORTHERN CAUCASUS

2021 ◽  
Vol 43 (4) ◽  
pp. 437-450
Author(s):  
Irina Malneva ◽  
Nina Kononova ◽  
Muhtar Hadzhiev
Keyword(s):  
Negative Impact ◽  
Climatic Conditions ◽  
Northern Caucasus ◽  
North Caucasus ◽  
Mountainous Regions ◽  
Technogenic Impact ◽  
The North ◽  
Geological Processes ◽  
Rock Formations ◽  
Operational Forecasts

The article presents an assessment of technogenic impact on the development of hazardous geological processes in the mountainous regions of the Northern Caucasus in the current century. Technogenic impact is determined by the stability of rock formations that make up the Krasnodar Territory, Kabardino-Balkaria, and North Ossetia relative to the impacts of other forces. It is also noted that the activity of hazardous geological processes is largely determined by the interaction of climatic conditions, which determine their speed, and technogenesis. Examples of problematic territories of the North Caucasus are given. To assess climatic changes and major catastrophes, a typology of atmospheric circulation in the Northern Hemisphere was developed under the leadership of B.L. Dzerdzeevsky. Typification materials from the period between 1899 and 2018 are posted in the public domain, at www.atmospheric-circulation.ru. The largest catastrophes, in which landslides and mudflows became more active, and the interaction of natural and man-made factors in these disasters are considered.Hazardous geological processes can disrupt the sustainable development of individual regions with their negative impact on the environment. The assessment of their danger is therefore of special current relevance. The article considers the possibility of predicting catastrophes associated with these processes. Long-term forecasts of landslides, mudflows and other processes continue to be important. The methodology of such forecasting was previously developed in sufficient detail. The greatest importance is assigned to operational forecasts that will make it possible to warn of possible danger hours or even days ahead.

scholarly journals Glacier changes in the west Kunlun Shan from 1970 to 2001 derived from Landsat TM/ETM+ and Chinese glacier inventory data

2007 ◽  
Vol 46 ◽  
pp. 204-208 ◽  
Author(s):  
Donghui Shangguan ◽  
Shiyin Liu ◽  
Yongjian Ding ◽  
Jing Li ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Ice Core ◽  
Research Area ◽  
Western China ◽  
Glacier Area ◽  
The South ◽  
Mountainous Regions ◽  
The North ◽  
Northern Tibetan Plateau ◽  
West Kunlun ◽  
Landsat Satellite

AbstractRecent studies have indicated that widespread wastage of glaciers in western China has occurred since the late 1970s. By using digitized glacier outlines derived from the 1970 inventory and Landsat satellite data from 1990/91 to 2001, we obtained area changes of about 278 glaciers with a total area of 2711.57 km2 in the heavily glaciated west Kunlun Shan (WKS) in the northern Tibetan Plateau (TP). Results indicate that the prevailing characteristic of glacier variation is ice wastage, and glacier area decreased by 10 km2 (0.4% of the total 1970 area) between 1970 and 2001. Both the south and north slopes of the WKS presented shrinkage during 1970–2001, but whereas on the north slope a slight enlargement of ice extent during 1970–90 was followed by a reduction of 0.2% during 1990–2001, on the south slope the glacier area decreased by 1.2% during 1970–91, with a small increment of 0.6% during 1991–2001. Comparisons with other glaciated mountainous regions in western China show that glaciers in the research area have experienced less retreat. Based on records from the Guliya ice core, we believe that an increase in air temperature was the main forcing factor for glacier shrinkage during 1970–2001.

scholarly journals Reanalysis of 44 Yr of Climate in the French Alps (1958–2002): Methodology, Model Validation, Climatology, and Trends for Air Temperature and Precipitation

2009 ◽  
Vol 48 (3) ◽  
pp. 429-449 ◽  
Author(s):  
Yves Durand ◽  
Martin Laternser ◽  
Gérald Giraud ◽  
Pierre Etchevers ◽  
Bernard Lesaffre ◽  
...  
Keyword(s):  
Air Temperature ◽  
Numerical Models ◽  
Surface Air Temperature ◽  
Positive Trend ◽  
Mountain Areas ◽  
Near Surface ◽  
French Alps ◽  
Mountainous Regions ◽  
Temperature And Precipitation ◽  
Analysis Scheme

Abstract Since the early 1990s, Météo-France has used an automatic system combining three numerical models to simulate meteorological parameters, snow cover stratification, and avalanche risk at various altitudes, aspects, and slopes for a number of mountainous regions in France. Given the lack of sufficient directly observed long-term snow data, this “SAFRAN”–Crocus–“MEPRA” (SCM) model chain, usually applied to operational avalanche forecasting, has been used to carry out and validate retrospective snow and weather climate analyses for the 1958–2002 period. The SAFRAN 2-m air temperature and precipitation climatology shows that the climate of the French Alps is temperate and is mainly determined by atmospheric westerly flow conditions. Vertical profiles of temperature and precipitation averaged over the whole period for altitudes up to 3000 m MSL show a relatively linear variation with altitude for different mountain areas with no constraint of that kind imposed by the analysis scheme itself. Over the observation period 1958–2002, the overall trend corresponds to an increase in the annual near-surface air temperature of about 1°C. However, variations are large at different altitudes and for different seasons and regions. This significantly positive trend is most obvious in the 1500–2000-m MSL altitude range, especially in the northwest regions, and exhibits a significant relationship with the North Atlantic Oscillation index over long periods. Precipitation data are diverse, making it hard to identify clear trends within the high year-to-year variability.

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