scholarly journals Climate change assessment for Mediterranean agricultural areas by statistical downscaling

2010 ◽  
Vol 10 (7) ◽  
pp. 1647-1661 ◽  
Author(s):  
L. Palatella ◽  
M. M. Miglietta ◽  
P. Paradisi ◽  
P. Lionello
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Statistical Downscaling ◽  
Principal Component ◽  
Summer Precipitation ◽  
Ebro River ◽  
Po Valley ◽  
Apulia Region ◽  
Climate Change Assessment ◽  
Agricultural Areas

Abstract. In this paper we produce projections of seasonal precipitation for four Mediterranean areas: Apulia region (Italy), Ebro river basin (Spain), Po valley (Italy) and Antalya province (Turkey). We performed the statistical downscaling using Canonical Correlation Analysis (CCA) in two versions: in one case Principal Component Analysis (PCA) filter is applied only to predictor and in the other to both predictor and predictand. After performing a validation test, CCA after PCA filter on both predictor and predictand has been chosen. Sea level pressure (SLP) is used as predictor. Downscaling has been carried out for the scenarios A2 and B2 on the basis of three GCM's: the CCCma-GCM2, the Csiro-MK2 and HadCM3. Three consecutive 30-year periods have been considered. For Summer precipitation in Apulia region we also use the 500 hPa temperature (T500) as predictor, obtaining comparable results. Results show different climate change signals in the four areas and confirm the need of an analysis that is capable of resolving internal differences within the Mediterranean region. The most robust signal is the reduction of Summer precipitation in the Ebro river basin. Other significative results are the increase of precipitation over Apulia in Summer, the reduction over the Po-valley in Spring and Autumn and the increase over the Antalya province in Summer and Autumn.

scholarly journals Climate change projections of boreal summer precipitation over tropical America by using statistical downscaling from CMIP5 models

2017 ◽  
Vol 12 (12) ◽  
pp. 124011 ◽  
Author(s):  
Reiner Palomino-Lemus ◽  
Samir Córdoba-Machado ◽  
Sonia Raquel Gámiz-Fortis ◽  
Yolanda Castro-Díez ◽  
María Jesús Esteban-Parra
Keyword(s):  
Climate Change ◽  
Statistical Downscaling ◽  
Summer Precipitation ◽  
Cmip5 Models ◽  
Boreal Summer ◽  
Climate Change Projections ◽  
Tropical America

scholarly journals Assessing Impacts of Climate Variability and Reforestation Activities on Water Resources in the Headwaters of the Segura River Basin (SE Spain)

2018 ◽  
Vol 10 (9) ◽  
pp. 3277 ◽  
Author(s):  
Javier Senent-Aparicio ◽  
Sitian Liu ◽  
Julio Pérez-Sánchez ◽  
Adrián López-Ballesteros ◽  
Patricia Jimeno-Sáez
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Water Resources ◽  
River Basin ◽  
Assessment Tool ◽  
Forest Area ◽  
Se Spain ◽  
Monthly Streamflow ◽  
Agricultural Areas ◽  
Water Assessment

Climate change and the land-use and land-cover changes (LULC) resulting from anthropic activity are important factors in the degradation of an ecosystem and in the availability of a basin’s water resources. To know how these activities affect the quantity of the water resources of basins, such as the Segura River Basin, is of vital importance. In this work, the Soil and Water Assessment Tool (SWAT) was used for the study of the abovementioned impacts. The model was validated by obtaining a Nash–Sutcliffe efficiency (NSE) of 0.88 and a percent bias (PBIAS) of 17.23%, indicating that SWAT accurately replicated monthly streamflow. Next, land-use maps for the years of 1956 and 2007 were used to establish a series of scenarios that allowed us to evaluate the effects of these activities on both joint and individual water resources. A reforestation plan applied in the basin during the 1970s caused that the forest area had almost doubled, whereas the agricultural areas and shrubland had been reduced by one-third. These modifications, together with the effect of climate change, have led to a decrease of 26.3% in the quantity of generated water resources, not only due to climate change but also due to the increase in forest area.

scholarly journals Can on-farm irrigation reservoirs enhance long-term sustainability of large irrigated systems? The case of Riegos del Alto Aragón (Spain)

2020 ◽  
Author(s):  
David Haro-Monteagudo ◽  
Leticia Palazón ◽  
Santiago Beguería
Keyword(s):  
Climate Change ◽  
Decision Making ◽  
River Basin ◽  
Irrigation District ◽  
Allocation Model ◽  
Ebro River ◽  
Irrigated Area ◽  
Environmental Objectives ◽  
On Farm

<p>With a total irrigated area above 127,000 ha divided into 58 sectors, the Riegos del Alto Aragón (RAA) irrigation district is currently the largest irrigated area in Spain and in the European Union. Also, it is the largest water user within the Gallego-Cinca subsystem within the Ebro River Basin, which also supplies water to 588 livestock operations, 10 industrial polygons, and 110 populated areas. Although there are plans to increase the irrigated area by another additional 47,000 ha, the system is currently close to its resource limit and several supply restrictions took place in the last years with consequent impacts on agricultural productivity. Moreover, this expansion of the irrigated area collides with environmental objectives in the region, mostly due to water quality and nature conservancy aspects, as well as with other water uses downstream.</p><p>The forecasted effects of climate change on future water resources produced in the Pyrenees (the major source of water in the system), as well as market prices, national and international trade and agricultural policies, among other variables, are surrounded by a high level of uncertainty that difficult investment decision-making. Some of the adaptation measures initially devised for the system, e.g. construction of new large reservoirs in the Gallego and Cinca rivers, require either confronting further environmental conflicts or large energy expenses, when not both. With the end of the era of large public works, there is a need to identify new and robust strategies for climate change adaptation. One of these strategies is the construction of private on-farm reservoirs within the RAA system that started in recent years.</p><p>The present work evaluates the contribution of on-farm reservoirs to enhancing the long-term sustainability of the RAA system using a multi-model and multi-scenario approach. The Soil and Water Assessment Tool (SWAT) was used to simulate water provisions from the Gallego-Cinca headwater system under an ensemble of downscaled climate models. Afterward, SWAT outputs were fed into a water allocation model built with AQUATOOL to simulate the management of the system's reservoirs, including on-farm reservoirs, and the water supply to the different demands. The performance of agricultural demands and compliance with environmental flow requirements in the system was evaluated for different on-farm reservoir sizes and combined with construction and operational costs to develop sustainability/investment curves. The outcomes have the potential to better inform decision-making from farmers in RAA as well as from managers in the Ebro River Basin Agency, providing further understanding of the system's dynamics under climatic change.</p>

Impacts of potential climate change on selected agroclimatic indices in Atlantic Canada

2005 ◽  
Vol 85 (2) ◽  
pp. 329-343 ◽  
Author(s):  
A. Bootsma ◽  
S. Gameda and D.W. McKenney
Keyword(s):  
Climate Change ◽  
Statistical Downscaling ◽  
Growing Degree Days ◽  
Climate Change Scenarios ◽  
Degree Days ◽  
Atlantic Region ◽  
Water Deficits ◽  
Heat Units ◽  
Agricultural Areas ◽  
The Impact

Agroclimatic indices (heat units and water deficits) were determined for the Atlantic region of Canada for a baseline climate (1961 to 1990 period) and for two future time periods (2010 to 2039 and 2040 to 2069). Climate scenarios for the future periods were primarily based on outputs from the Canadian General Circulation Model (GCM) that included the effects of aerosols (CGCMI-A), but variability introduced by multiple GCM experiments was also examined. Climatic data for all three periods were interpolated to a grid of about 10 to 15 km. Agroclimatic indices were computed and mapped based on the gridded data. Based on CGCMI-A scenarios interpolated to the fine grid, average crop heat units (CHU) would increase by 300 to 500 CHU for the 2010 to 2039 period and by 500 to 700 CHU for the 2040 to 2069 period in the main agricultural areas of the Atlantic region. However, increases in CHU for the 2040 to 2069 period typically varied from 450 to 1650 units in these regions when variability among GCM experiments was considered, resulting in a projected range of 2650 to 4000 available CHU. Effective growing degree-days above 5°C (EGDD) typically increased by about 400 units for the 2040 to 2069 period in the main agricultural areas, resulting in available EGDD from 1800 to over 2000 units. Uncertainty introduced by multiple GCMs increased the range from 1700 to 2700 EGDD. A decrease in heat units (cooling) is anticipated along part of the coast of Labrador. Anticipated changes in water deficits (DEFICIT), defined as the amount by which potential evapotranspiration exceeded precipitation over the growing season, typically ranged from +50 to −50 mm for both periods, but this range widened from +50 to −100 mm when variability among GCM experiments was considered. The greatest increases in deficits were expected in the central region of New Brunswick for the 2040 to 2069 period. Our interpolation procedures estimated mean winter and summer temperature changes that were 1.4°C on average lower than a statistical downscaling procedure (SDSM) for four locations. Increases in precipitation during summer and autumn averaged 20% less than SDSM. During periods when SDSM estimated relatively small changes in temperature or precipitation, our interpolation procedure tended to produce changes that were larger than SDSM. Additional investigations would be beneficial that explore the impact of a range of scenarios from other GCM models, other downscaling methods and the potential effects of change in climate variability on these agroclimatic indices. Potential impacts of these changes on crop yields and production in the region also need to be explored. Key words: Crop heat units, effective growing degree-days, water deficits, climate change scenarios, statistical downscaling, spatial interpolation

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