Analysis of rainfall trends and dry periods on a pluviometric gradient representative of Mediterranean climate in the Duero Basin, Spain

Ceballos, Antonio; Martínez-Fernández, J.; Luengo-Ugidos, Miguel Ángel

doi:10.1016/j.jaridenv.2003.07.002

Cited by 91 publications

(79 citation statements)

References 33 publications

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“…As described in the literature (Ceballos et al 2004;Nel2009;Ngongondo et al 2011), PCI values below 10 indicate a uniform monthly rainfall distribution in the year, whereas values from 11 to 20 denote seasonality in rainfall distribution. Values above 20 correspond to climates with substantial monthly variability in rainfall amounts (Nel 2009 and references therein).…”

Section: Rainfall Mean Characteristicsmentioning

confidence: 95%

“…This is paramount in water resource planning, agricultural planning, flood frequency monitoring, climate change impacts, environmental assessments, and ecology (Ngongondo et al 2011;Michaelides et al 2009;Ceballos et al 2004). Such information is still scarce because of the few studies that have analyzed the relationship of climate patterns and water management among others especially in the East Africa region.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Nsubuga

Olwoch

Rautenbach

et al. 2013

Theor Appl Climatol

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A methodology has been applied to investigate the spatial variability and trends existent in a mid-twentieth century climatic time series (for the period recorded by 58 climatic stations in the Albert-Victoria water management area in Uganda. Data were subjected to quality checks before further processing. In the present work, temporal trends were analyzed using Mann-Kendall and linear regression methods. Heterogeneity of monthly rainfall was investigated using the precipitation concentration index (PCI). Results revealed that 53 % of stations have positive trends where 25 % are statistically significant and 45 % of stations have negative trends with 23 % being statistically significant. Very strong trends at 99 % significance level were revealed at 12 stations.

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Section: Rainfall Mean Characteristicsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Nsubuga

Olwoch

Rautenbach

et al. 2013

Theor Appl Climatol

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“…These are determined according to Eq. (1), where m is the number of days in the ith month and 1( q ) is the binary operator that returns 1 if the daily precipitation intensity P i,j is larger than 1 mm (wet), and 0 otherwise (dry) (Ceballos et al, 2004). In particular, Eqs.…”

Section: Post-processing Of Forecast Productsmentioning

confidence: 99%

A coupled human–natural system to assess the operational value of weather and climate services for agriculture

Liu

Giuliani

Castelletti

2017

Hydrol. Earth Syst. Sci.

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Abstract. Recent advances in weather and climate (W&C) services are showing increasing forecast skills over seasonal and longer timescales, potentially providing valuable support in informing decisions in a variety of economic sectors. Quantifying this value, however, might not be straightforward as better forecast quality does not necessarily imply better decisions by the end users, especially when forecasts do not reach their final users, when providers are not trusted, or when forecasts are not appropriately understood. In this study, we contribute an assessment framework to evaluate the operational value of W&C services for informing agricultural practices by complementing traditional forecast quality assessments with a coupled human-natural system behavioural model which reproduces farmers' decisions. This allows a more critical assessment of the forecast value mediated by the end users' perspective, including farmers' risk attitudes and behavioural factors. The application to an agricultural area in northern Italy shows that the quality of state-ofthe-art W&C services is still limited in predicting the weather and the crop yield of the incoming agricultural season, with ECMWF annual products simulated by the IFS/HOPE model resulting in the most skillful product in the study area. However, we also show that the accuracy of estimating crop yield and the probability of making optimal decisions are not necessarily linearly correlated, with the overall assessment procedure being strongly impacted by the behavioural attitudes of farmers, which can produce rank reversals in the quantification of the W&C services operational value depending on the different perceptions of risk and uncertainty.

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“…Coles, 2001]. No significant temporal trends have been found for the region and time period analyzed [Ceballos et al, 2004]. To assess temporal clustering among extreme deficits, the so-called extremal index that measures the reciprocal of the limiting mean cluster size of extremes has been estimated by using the method of Ferro and Segers [2003].…”

Section: Defining Extreme Precipitation Deficitsmentioning

confidence: 99%

“…The level depends on the application at hand [cf. Mathugama and Peiris, 2011;Lana et al, 2008;Ceballos et al, 2004]. In this study, monthly precipitation deficits are analyzed with the Standard Precipitation Index (SPI) and with a multivariate extreme value analysis [see, e.g., Coles, 2001;Beirlant et al, 2004;Resnick, 2007] of cumulative precipitation below 30.5 mm.…”

Section: Introductionmentioning

confidence: 99%

Spatial assessment of precipitation deficits in the Duero basin (central Spain) with multivariate extreme value statistics

2013

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[1] Nonirrigated agriculture on the Iberian Peninsula is regularly affected by dry periods that can cause important losses. This paper focuses on the comparison of the classical Standard Precipitation Index (SPI) with a fragility index developed by the multivariate extreme value theory community, which is used to describe monthly precipitation deficits below 30.5 mm (about 1 mm/d) in the Spanish Duero basin. The multivariate extreme value model allows to capture relevant information concerning the dependence structure among extreme precipitation deficits. Maps of those extremal dependence summaries and of loadings of principal components of the SPI provide quantitative information for water management. In addition, jointly analyzing data from several stations improves the inference of uncertainty. Spatial patterns of extremal dependence emerged with respect to orographic features. Most severe dry spells occur in the southeast of the Duero basin. In central plain of the Duero basin, a predominantly agricultural area, a strong fragility index for severity of dry spells is particularly found in eastern regions. Results of the MEVT and SPI analysis point in the same direction. Beyond this, the MEVT assessment gives a quantitative measure of the dependence between stations and regions. Estimates of return periods for extreme dry spell severity are discussed. Deficits below 42.7 mm are also analyzed.Citation: Kallache, M., P. Naveau, and M. Vrac (2013), Spatial assessment of precipitation deficits in the Duero basin (central Spain) with multivariate extreme value statistics, Water Resour. Res., 49,[6716][6717][6718][6719][6720][6721][6722][6723][6724][6725][6726][6727][6728][6729][6730]

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Analysis of rainfall trends and dry periods on a pluviometric gradient representative of Mediterranean climate in the Duero Basin, Spain

Cited by 91 publications

References 33 publications

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

Analysis of mid-twentieth century rainfall trends and variability over southwestern Uganda

A coupled human–natural system to assess the operational value of weather and climate services for agriculture

Spatial assessment of precipitation deficits in the Duero basin (central Spain) with multivariate extreme value statistics

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