scholarly journals Climate Trends Impact on the Snowfall Regime in Mediterranean Mountain Areas: Future Scenario Assessment in Sierra Nevada (Spain)

Water ◽  
2018 ◽  
Vol 10 (6) ◽  
pp. 720 ◽  
Author(s):  
María Pérez-Palazón ◽  
Rafael Pimentel ◽  
María Polo
Keyword(s):  
Sierra Nevada ◽  
Climate Trends ◽  
Mountain Areas ◽  
Future Scenario ◽  
Scenario Assessment

scholarly journals Formation Patterns of Mediterranean High-Mountain Water-Bodies in Sierra-Nevada, SE Spain

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 438
Author(s):  
Jose Luis Diaz-Hernandez ◽  
Antonio Jose Herrera-Martinez
Keyword(s):  
Sierra Nevada ◽  
Unknown Origin ◽  
Slope Instability ◽  
Water Bodies ◽  
High Mountain ◽  
Mountain Areas ◽  
Glacial Processes ◽  
The Mediterranean ◽  
Water Volumes

At present, there is a lack of detailed understanding on how the factors converging on water variables from mountain areas modify the quantity and quality of their watercourses, which are features determining these areas’ hydrological contribution to downstream regions. In order to remedy this situation to some extent, we studied the water-bodies of the western sector of the Sierra Nevada massif (Spain). Since thaw is a necessary but not sufficient contributor to the formation of these fragile water-bodies, we carried out field visits to identify their number, size and spatial distribution as well as their different modelling processes. The best-defined water-bodies were the result of glacial processes, such as overdeepening and moraine dams. These water-bodies are the highest in the massif (2918 m mean altitude), the largest and the deepest, making up 72% of the total. Another group is formed by hillside instability phenomena, which are very dynamic and are related to a variety of processes. The resulting water-bodies are irregular and located at lower altitudes (2842 m mean altitude), representing 25% of the total. The third group is the smallest (3%), with one subgroup formed by anthropic causes and another formed from unknown origin. It has recently been found that the Mediterranean and Atlantic watersheds of this massif are somewhat paradoxical in behaviour, since, despite its higher xericity, the Mediterranean watershed generally has higher water contents than the Atlantic. The overall cause of these discrepancies between watersheds is not connected to their formation processes. However, we found that the classification of water volumes by the manners of formation of their water-bodies is not coherent with the associated green fringes because of the anomalous behaviour of the water-bodies formed by moraine dams. This discrepancy is largely due to the passive role of the water retained in this type of water-body as it depends on the characteristics of its hollows. The water-bodies of Sierra Nevada close to the peak line (2918 m mean altitude) are therefore highly dependent on the glacial processes that created the hollows in which they are located. Slope instability created water-bodies mainly located at lower altitudes (2842 m mean altitude), representing tectonic weak zones or accumulation of debris, which are influenced by intense slope dynamics. These water-bodies are therefore more fragile, and their existence is probably more short-lived than that of bodies created under glacial conditions.

scholarly journals Glacier changes and climate trends derived from multiple sources in the data scarce Cordillera Vilcanota region, southern Peruvian Andes

2013 ◽  
Vol 7 (1) ◽  
pp. 103-118 ◽  
Author(s):  
N. Salzmann ◽  
C. Huggel ◽  
M. Rohrer ◽  
W. Silverio ◽  
B. G. Mark ◽  
...  
Keyword(s):  
Air Temperature ◽  
Specific Humidity ◽  
Spatial And Temporal Variability ◽  
Moderate Increase ◽  
Climate Data ◽  
Climate Trends ◽  
Multiple Sources ◽  
Mountain Areas ◽  
Peruvian Andes ◽  
Glacier Changes

Abstract. The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer) tropics because of the very distinct wet/dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern, and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. However, in remote mountain areas, spatial and temporal data coverage is typically very scarce and this is further complicated by a high spatial and temporal variability in regions with complex topography. Here, we present an approach on how to deal with these constraints. For the Cordillera Vilcanota (southern Peruvian Andes), which is the second largest glacierized cordillera in Peru (after the Cordillera Blanca) and also comprises the Quelccaya Ice Cap, we assimilate a comprehensive multi-decadal collection of available glacier and climate data from multiple sources (satellite images, meteorological station data and climate reanalysis), and analyze them for respective changes in glacier area and volume and related trends in air temperature, precipitation and in a more general manner for specific humidity. While we found only marginal glacier changes between 1962 and 1985, there has been a massive ice loss since 1985 (about 30% of area and about 45% of volume). These high numbers corroborate studies from other glacierized cordilleras in Peru. The climate data show overall a moderate increase in air temperature, mostly weak and not significant trends for precipitation sums and probably cannot in full explain the observed substantial ice loss. Therefore, the likely increase of specific humidity in the upper troposphere, where the glaciers are located, is further discussed and we conclude that it played a major role in the observed massive ice loss of the Cordillera Vilcanota over the past decades.

scholarly journals Characterization and challenges of livestock farming in Mediterranean protected mountain areas (Sierra Nevada, Spain)

2020 ◽  
Vol 18 (1) ◽  
pp. e0601
Author(s):  
Francisco A. Ruiz ◽  
Marta Vázquez ◽  
Jose A. Camuñez ◽  
Jose M. Castel ◽  
Yolanda Mena
Keyword(s):  
Sierra Nevada ◽  
Protected Area ◽  
Farming Systems ◽  
Social Recognition ◽  
Production Costs ◽  
Medium Size ◽  
Livestock Farming ◽  
Mountain Areas ◽  
Livestock Farming Systems ◽  
Grazing Lands

Aim of study: To characterize and analyse the extensive livestock farming systems in environmental protected area and propose strategies for their sustainable improvement.Area of study: Sierra Nevada Protected Area (Spain)Material and methods: Data were collected from a sample of 85 farmers and 48 experts. The information from farmers was expressed in 35 variables, 23 of which were qualitative and 12 quantitative. A multivariate analysis was conducted.Main results: The principal components explained 71.2% of the total variance and the k-means cluster analysis identified three groups: C1 (38 farms), medium-size farms with a predominance of goats and relative dairy specialization; C2 (12 farms), large-size farms with extensive grazing lands, a high proportion of meat purpose animals and managed by young and dynamic farmers and C3 (35 farms), medium-size farms with a high proportion of meat purpose animals and undeveloped business management. The main problems reported were: insufficient pastures for livestock, stagnation of product prices, lack of generational renewal and need for social recognition of livestock farming. These obstacles could be overcome by implementing measures aimed at improving feed self-sufficiency -and thus reduce production costs- increasing income through social recognition of farming, achieving product differentiation, and strengthening short marketing channels. This would be favoured by an increase in associationism and specialized training.Research highlights: Farm management and marketing are important for improve these farming systems. The extensive livestock farming continues to be an important activity in European protected mountain areas.

scholarly journals Glacier changes and climate trends derived from multiple sources in the data scarce Cordillera Vilcanota region, Southern Peruvian Andes

2012 ◽  
Vol 6 (1) ◽  
pp. 387-426 ◽  
Author(s):  
N. Salzmann ◽  
C. Huggel ◽  
M. Rohrer ◽  
W. Silverio ◽  
B. G. Mark ◽  
...  
Keyword(s):  
Air Temperature ◽  
Specific Humidity ◽  
Spatial And Temporal Variability ◽  
Climate Data ◽  
Climate Trends ◽  
Multiple Sources ◽  
Mountain Areas ◽  
Peruvian Andes ◽  
The Past ◽  
Alpine Regions

Abstract. The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer) tropics because of the very distinct wet-dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. However, in remote mountain areas, spatial and temporal data coverage is typically very scarce and this is further complicated by a high spatial and temporal variability in regions with complex topography. Here, we present an approach on how to deal with these constraints. For the Cordillera Vilcanota (Southern Peruvian Andes), which is the second largest glacierised Cordillera in Peru (after the Cordillera Blanca) and also comprises the Quelccaya Ice Cap, we assimilate a comprehensive multi-decadal collection of available glacier and climate data from multiple sources (satellite images, meteorological station data and climate Reanalysis), and analyze them for respective changes in glacier area and volume and related trends in air temperature, precipitation and specific humidity. In general, the climate data show a moderate (compared to other alpine regions) increase in air temperature, weak and not significant trends for precipitation sums, and an increase in specific humidity at the 500 hPa level. The latter is consistent with observed increase in water vapour at the tropopause level during the past decades. It is likely that the increase in specific humidity played a major role in the observed massive ice loss of the Cordillera Vilcanota over the past decades.

scholarly journals Degradation of buried ice and permafrost in the Veleta cirque (Sierra Nevada, Spain) from 2006 to 2013 as a response to recent climate trends

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 979-993 ◽  
Author(s):  
A. Gómez-Ortiz ◽  
M. Oliva ◽  
F. Salvador-Franch ◽  
M. Salvà-Catarineu ◽  
D. Palacios ◽  
...  
Keyword(s):  
20Th Century ◽  
Sierra Nevada ◽  
Active Layer ◽  
The Body ◽  
Ice Age ◽  
Climate Trends ◽  
Rock Glacier ◽  
Climate Conditions ◽  
Discontinuous Permafrost ◽  
Recent Climate

Abstract. The Veleta cirque is located at the foot of the Veleta peak, one of the highest summits of the Sierra Nevada National Park (southern Spain). This cirque was the source of a glacier valley during the Quaternary cold periods. During the Little Ice Age it sheltered a small glacier, the most southerly in Europe, about which we have possessed written records since the 17th century. This glacier still had ice residues until the mid-20th century. This ice is no longer visible, but a residue persists along with discontinuous permafrost trapped under strata of rock blocks that make up an incipient rock glacier. From 2006 to 2013, this rock glacier was monitored by measurement of the temperature of the active layer, the degree of snow cover on the ground, movements of the body of the rock glacier and geophysical prospection inside it. The results show that the relict ice and trapped permafrost have been steadily declining. The processes that explain this degradation occur in chain, starting from the external radiation that affects the ground in summer, which is when the temperatures are higher. In effect, when this radiation steadily melts the snow on the ground, the thermal expansive wave advances into the heart of the active layer, reaching the ceiling of the frozen mass, which it then degrades and melts. In this entire linked process, the circulation of meltwaters fulfils a highly significant function, as they act as heat transmitters. The complementary nature of these processes explains the subsidence and continuous changes in the entire clastic pack and the melting of the frozen ceiling on which it rests. This happens in summer in just a few weeks. All these events, in particular the geomorphological ones, take place on the Sierra Nevada peaks within certain climate conditions that are at present unfavourable to the maintenance of snow on the ground in summer. These conditions could be related to recent variations in the climate, starting in the mid-19th century and most markedly since the second half of the 20th century. The work and results highlight the climate sensitivity of the peaks of the Sierra Nevada to the effect of climate change and its impact on the dynamics of ecosystems, which is a benchmark for evaluating the current evolution of landscapes of Mediterranean high mountains.

scholarly journals Simulating 3-D radiative transfer effects over the Sierra Nevada Mountains using WRF

2012 ◽  
Vol 12 (20) ◽  
pp. 9965-9976 ◽  
Author(s):  
Y. Gu ◽  
K. N. Liou ◽  
W.-L. Lee ◽  
L. R. Leung
Keyword(s):  
Radiative Transfer ◽  
Latent Heat ◽  
Sierra Nevada ◽  
Early Morning ◽  
Heat Fluxes ◽  
Solar Insolation ◽  
Mountain Areas ◽  
Late Afternoon ◽  
Surface Skin Temperature ◽  
Mountain Effect

Abstract. A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF) model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra-Nevada in the western United States as a testbed, we show that mountain effect could produce up to −50 to + 50 W m−2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 °C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shaded side. Substantial differences are found in the morning hours from 8–10 a.m. and in the afternoon around 3–5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to −40 g m−2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between −12~12 W m−2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the domain-averaged diurnal variation over the Sierras show that the mountain area receives more solar insolation during early morning and late afternoon, resulting in enhanced upward sensible heat and latent heat fluxes from the surface and a corresponding increase in surface skin temperature. During the middle of the day, however, the surface insolation and heat fluxes show negative changes, indicating a cooling effect. Hence overall, the diurnal variations of surface temperature and surface fluxes in the Sierra-Nevada are reduced through the interactions of radiative transfer and mountains. The hourly differences of the surface solar insolation in higher elevated regions, however, show smaller magnitude in negative changes during the middle of the day and possibly more solar fluxes received during the whole day.

scholarly journals Travel times of principal P and S phases over small distances in southern California*

1944 ◽  
Vol 34 (1) ◽  
pp. 13-32
Author(s):  
B. Gutenberg
Keyword(s):  
Sierra Nevada ◽  
Southern California ◽  
Epicentral Distance ◽  
Focal Depth ◽  
Coastal Areas ◽  
Travel Times ◽  
Mountain Areas ◽  
Arrival Times ◽  
Order Of Magnitude ◽  
Characteristic Values

Summary Study of arrival times of the principal phases in fifty of the larger and better recorded earthquakes in southern California resulted in the following travel times t (seconds) and apparent velocities V (km/sec.): Pt = 0.1793DV = 5.577St = −0.5 + 0.3066DV = 3.26Pyt = 1.2+0.1654ΔV = 6.047Syt = 2.1 + 0.274ΔV = 3.65Pnt = x + 0.124ΔV = 8.06Snt = y + 0.225ΔV = 4.45 Δ = epicentral distance, D2 = Δ2 + h2, h = focal depth. x and y depend on the region; the following are characteristic values Coastal areas,Mountain areas,NorthernSierralow valleyssoutheastern Calif.Owens ValleyNevadax67910±sec.y8½9½12½14±sec. The average true velocities of Py and Sy are about one-third of one per cent, those of Pn and Sn about one-half of one per cent, smaller than the corresponding apparent velocities. In the uppermost 50 km. the velocity increases with depth. The order of magnitude of this increase is roughly 1 per cent per 10 kilometers, but larger in the uppermost one or two kilometers. It can be found from a study of amplitudes (Gutenberg, 1943c); its effect on the travel times exceeds the limits of error by too small an amount to be ascertained beyond doubt from the data of the present paper. The curvature of the earth can be disregarded within the range of distances used (in general not exceeding 800 km.). The effect of “mountain roots” on the travel times of Pn and Sn is investigated. Reproduction of travel-time curves and recalculation of the thickness of the various layers must wait until a study of other (especially reflected) recorded phases now under way is finished. Preliminary values are 18 km. for the thickness of the granitic layer with small local variations, and about 35 km. for the total of the crustal layers in the coastal areas of southern California with an increase inland approaching twice that amount under the Sierra Nevada.

scholarly journals Simulating 3-D radiative transfer effects over the Sierra Nevada mountains using WRF

2012 ◽  
Vol 12 (8) ◽  
pp. 19897-19920
Author(s):  
Y. Gu ◽  
K. N. Liou ◽  
W.-L. Lee ◽  
L. R. Leung
Keyword(s):  
Radiative Transfer ◽  
Latent Heat ◽  
Sierra Nevada ◽  
Early Morning ◽  
Heat Fluxes ◽  
Solar Insolation ◽  
Mountain Areas ◽  
Late Afternoon ◽  
Surface Skin Temperature ◽  
Mountain Effect

Abstract. A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF) model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra Nevada in the Western United States as a testbed, we show that mountain effect could produce up to −50 to +50 W m−2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 °C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shade side. Substantial differences are found in the morning hours from 8–10 a.m. and in the afternoon around 3–5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to −40 g m−2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between −12~12 W m−2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the domain-averaged diurnal variation over the Sierras show that the mountain area receives more solar insolation during early morning and late afternoon, resulting in enhanced upward sensible heat and latent heat fluxes from the surface and a corresponding increase in surface skin temperature. During the middle of the day, however, the surface insolation and heat fluxes show negative changes, indicating a cooling effect. Hence overall, the diurnal variations of surface temperature and surface fluxes in the Sierra Nevada are reduced through the interactions of radiative transfer and mountains. The hourly differences of the surface solar insolation in higher elevated regions, however, show smaller magnitude in negative changes during the middle of the day and possibly more solar fluxes received during the whole day.

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