Extreme Rainfall Indices in Southern Levant and Related Large-Scale Atmospheric Circulation Patterns: A Spatial and Temporal Analysis

This study aims to provide a comprehensive spatio-temporal analysis of the annual and seasonal extreme rainfall indices over the southern Levant from 1970 to 2020. For this, temporal and spatial trends of 15 climate extreme indices based on daily precipitation at 66 stations distributed across Israel and Palestine territories were annually and seasonally analyzed through the nonparametric Mann–Kendall test and the Sen’s slope estimator. The annual averages for frequency-based extreme indices exhibited decreasing trends, significantly for the Consecutive Dry Days. In contrast, the percentiles- and intensity-based extreme indices showed increasing trends, significant for extremely wet days, Max 1- and 3-day precipitation amount indices. The study area had expanding periods of extreme dry spells for spring and correspondingly shortening extreme wet spells for spring, winter and the combined winter–spring. Moreover, most of spring indices showed negative trends. Conversely, most winter indices displayed positive trends. Regarding the influence of large-scale circulation patterns, the North Sea Caspian pattern, the Western Mediterranean Oscillation, and ENSO were the primary regulators of the winter, spring, and autumn extreme indices, respectively. These findings contribute to a better understanding of extreme rainfall variability in the Levant region and could be utilized in the management of water resources, drought monitoring, and flood control.FEDER/Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades P20_00035Ministry of Science and Innovation through the FEDER funds from the Spanish Pluriregional Operational Program 2014-2020 (POPE), LifeWatch-ERIC action line LifeWatch-2019-10-UGR-0

Evaluación de simulaciones de la precipitación en clima presente usando el modelo WRF en la Península Ibérica

En este estudio se ha llevado a cabo un conjunto de simulaciones de alta resolución espacio-temporal para un periodo de 31 años haciendo uso del modelo regional Weather Reserch and Forecasting (WRF) con el fin de evaluar la capacidad del modelo para simular la variabilidad de las precipitaciones en la Península Ibérica. Las simulaciones se realizaron usando como condiciones iniciales y de contorno los datos de reanálisis de ERA-Interim, como “condiciones de contorno perfectas”, y las salidas globales del modelo CMIP5 CESM corregidas en sesgo, sobre un dominio centrado en la PI anidado en el dominio EURO-CORDEX. La evaluación se basó en la comparación de las salidas del modelo con los datos observacionales Spain02 para las precipitaciones en España y PT02 para Portugal, a diferentes escalas temporales con el objetivo de poder averiguar si las simulaciones regionalizadas son capaces de capturar tanto los valores medios como los eventos extremos. Los resultados indican que aunque existen ciertos errores substanciales, WRF es capaz de capturar los principales patrones espaciales de la precipitación en la PI, resultando una herramienta útil a la hora de realizar simulaciones regionales para zonas con una topografía compleja como es la Península Ibérica.A set of 31-yr high-resolution simulations has been carried out with the regional Weather Research and Forecasting (WRF) model in order to evaluate its capability to simulate precipitation variability in the Iberian Peninsula. The WRF model was forced by the ERA-Interim data as “perfect boundary conditions”, and the global bias-corrected climate model outputs from CMIP5 CESM model, over a domain encompassing the IP and nested in the coarser EURO-CORDEX domain. Evaluation was based on comparison at different time scales in order to assess the model ability to capture long-term mean precipitation values and high-order statistics (extreme events). For this end, we used two different observational gridded datasets: the Spain02 data for Spanish precipitation and the PT02 data for Portugal. Although considerable errors are still observed, results show that WRF is able to capture the main spatial precipitation patterns in IP. Therefore, we can say that WRF provides useful information at regional scale, with significant improvement in complex terrain areas such as Iberian Peninsula.Este estudio está financiado por los proyectos P11-RNM-7941 (Junta de Andalucía-Spain) y CGL2013-48539-R (MINECO-Spain, FEDER)

Variabilidad estacional de los caudales en Ecuador en el periodo 1964-2014

El objetivo principal de este estudio es analizar las tendencias en el caudal de los ríos de Ecuador. Para este fin, se han utilizado los datos de caudal de la red de estaciones hidrológicas, proporcionados por el Instituto Nacional de Meteorología e Hidrología de Ecuador (IHNAMI), distribuidas en el territorio ecuatoriano y situadas estratégicamente en las cuencas de los principales ríos. Se seleccionó un número de 26 estaciones con disponibilidad de datos diarios sin discontinuidad durante el período de 51 años (1964-2014). Mediante el test de Man-Kendall y pendiente de Sen, se han evaluado las tendencias del caudal a escala mensual. Por último, se analiza la relación entre la variabilidad del caudal y el ENSO, fuente principal de variabilidad climática en la región.The main objective of this study is to analyze trends in the streamflow of the rivers of Ecuador. For this end, we use the streamflow data from the network of hydrological stations, provided by the Instituto Nacional de Meteorología e Hidrología de Ecuador (IHNAMI), distributed over the Ecuadorian territory and strategically located in the watersheds of its main rivers. A number of 26 stations with a continuous period of daily data during 51 years period (1964-2014) was selected. Trends of the streamflow rates have been evaluated at monthly time scales using Man-Kendall test and Sens slope. Finally, we analyze the relationship between the streamflow variability and the ENSO, which is the major climate variability source in the region.Este trabajo ha sido financiado por los proyectos P11-RNM-7941 (Junta de Andalucía-España) and CGL2013-48539-R (MINECO-España, FEDER)

Coupling study of the Variable Infiltration Capacity (VIC) model with Weather Research and Forecasting (WRF) model to simulate the streamflow in the Guadalquivir Basin

Variable Infiltration Capacity (VIC) model is a large-scale hydrologic model. Land surface is modeled as a grid of large and uniform cells with sub-grid heterogeneity (e.g. land cover), while water influx is local, only depending from the interaction between grid cell and local atmosphere environment. Water streamflow is obtained separately from the land surface simulation, using the Routing Model. The goal of this work consists into set an optimal hydrological and climate model to study the evolution of the streamflow of Guadalquivir Basin, with different future land use, land cover and climate scenarios, implemented with the regional Weather Research and Forecasting (WRF) model. In this work we present some results concerning the calibration of the most relevant parameters of VIC model, comparing the streamflow simulations obtained from the observational climate data SPAIN02 and WRF outputs databases, with the use of observational reservoirs and gauging stations daily streamflow time series, obtained from CEDEX database, in the time period 1988-1997.El modelo Variable Infiltration Capacity (VIC) es un modelo hidrológico de gran escala. La superficie terrestre es modelada considerando una gran rejilla de celdas uniformes que presentan heterogeneidad a escala de sub-rejilla (esto es, cubierta superficial), mientras que el flujo de agua es local, únicamente dependiente de la interacción entre celdas y el medio ambiente local. El caudal de agua se obtiene separadamente a partir de la simulación de la superficie terrestre usando el denominado modelo Routing. El objetivo de este trabajo consiste en calibrar un modelo hidrológico y climático de forma óptima con el fin de estudiar la evolución del caudal en la Cuenca del Guadalquivir, con diferentes posibles usos del suelo futuros, cobertura superficial y escenarios climáticos, implementado con el modelo regional Weather Research and Forecasting (WRF). En este trabajo se presentan resultados relativos a la calibración de los parámetros más relevantes del modelo VIC, comparando las simulaciones de caudal obtenidas por el mismo a partir de los datos climáticos observacionales de SPAIN02 y de las salidas del modelo WRF, con los datos de caudal diario observacionales del CEDEX, para el periodo 1988-1997.This work has been financed by the projects P11-RNM-7941 (Junta de Andalucía-Spain) and CGL2013-48539-R (MINECO-Spain, FEDER)

Regional drought variability assessment over Spain using WRF model

This study assesses the ability of the Weather Research & Forecasting (WRF) model to reproduce dry and wet periods in a complex terrain region such as Spain. For this end, we have computed two different drought indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI), which is able to identify the drought patterns in a context of global warming. For comparative purposes, we also computed the drought indices using two different data sources as observational data: the monthly rainfall from MOPREDAS and the (maximum and minimum) monthly temperature from MOTEDAS gridded datasets. ERA-Interim data were also used to calculate the drought indices in order to determinate the improvement obtained using dynamical downscaling regarding to the driving data. Results show that WRF provides an improvement over ERA-Interim in term of droughts simulations, presenting higher temporal correlations with respect to observational data. This fact suggests that WRF outputs may be more suitable than larger-scale fields from General Circulation Models (GCMs) to perform future projections of droughts events.Este estudio evalúa la habilidad del modelo Weather Research & Forecasting (WRF) para reproducir periodos húmedos y secos en terrenos geográficamente complejos como España. Con este objetivo se han calculado dos índices de sequía diferentes: el Índice Estandarizado de Precipitación (SPI) y el Índice Estandarizado de Precipitación Evapotranspiración (SPEI), capaz de identificar patrones de sequía en el contexto de calentamiento global. Con propósitos comparativos, se calcularon también los índices de sequía usando dos bases de datos diferentes como datos observacionales: las precipitaciones mensuales de los datos en rejilla de MOPREDAS y las temperaturas (máximas y mínimas) mensuales de MOTEDAS. Los resultados muestran que las salidas del modelo WRF suponen una mejora con respecto a los datos de ERA-Interim en cuanto a las simulaciones de sequías presentando mayores coeficientes de correlación temporal con los datos observacionales. Este hecho sugiere que las salidas de WRF pueden ser más idóneas que los datos de Modelos Climáticos Globales (GCMs) a la hora de realizar proyecciones futuras para episodios de sequía.This work has been financed by the projects P11-RNM-7941 (Junta de Andalucía-Spain) and CGL2013-48539-R (MINECO-Spain, FEDER)

Extreme Rainfall Indices in Southern Levant and Related Large-Scale Atmospheric Circulation Patterns: A Spatial and Temporal Analysis

This study aims to provide a comprehensive spatio-temporal analysis of the annual and seasonal extreme rainfall indices over the southern Levant from 1970 to 2020. For this, temporal and spatial trends of 15 climate extreme indices based on daily precipitation at 66 stations distributed across Israel and Palestine territories were annually and seasonally analyzed through the nonparametric Mann–Kendall test and the Sen’s slope estimator. The annual averages for frequency-based extreme indices exhibited decreasing trends, significantly for the Consecutive Dry Days. In contrast, the percentiles- and intensity-based extreme indices showed increasing trends, significant for extremely wet days, Max 1- and 3-day precipitation amount indices. The study area had expanding periods of extreme dry spells for spring and correspondingly shortening extreme wet spells for spring, winter and the combined winter–spring. Moreover, most of spring indices showed negative trends. Conversely, most winter indices displayed positive trends. Regarding the influence of large-scale circulation patterns, the North Sea Caspian pattern, the Western Mediterranean Oscillation, and ENSO were the primary regulators of the winter, spring, and autumn extreme indices, respectively. These findings contribute to a better understanding of extreme rainfall variability in the Levant region and could be utilized in the management of water resources, drought monitoring, and flood control

Assessing Future Drought Conditions over the Iberian Peninsula: The Impact of Using Different Periods to Compute the SPEI

Future drought-hazard assessments using standardized indices depend on the period used to calibrate the probability distributions. This appears to be particularly important in a changing climate with significant trends in drought-related variables. This study explores the effect of using different approaches to project droughts, with a focus on changes in drought characteristics (frequency, duration, time spent in drought, and spatial extent), estimated with a calibration period covering recent past and future conditions (self-calibrated indices), and another one that only applies recent-past records (relative indices). The analysis focused on the Iberian Peninsula (IP), a hotspot region where climate projections indicate significant changes by the end of this century. To do this, a EURO-CORDEX multi-model ensemble under RCP8.5 was used to calculate the Standardized Precipitation-Evapotranspiration Index (SPEI) at both 3- and 12-month timescales. The results suggest that projections of drought characteristics strongly depend on the period used to calibrate the SPEI, particularly at a 12-month timescale. Overall, differences were larger for the near future when relative indices indicated more severe droughts. For the distant future, changes were more similar, although self-calibrated indices revealed more frequent and longer-lasting droughts and the relative ones a drought worsening associated with extremely prolonged drought events.FEDER/Junta de Andalucía-Ministry of Economy and Knowledge/Project [B-RNM-336-UGR18]Spanish Ministry of Economy, Industry and CompetitivenessEuropean Community Funds (FEDER) [CGL2017-89836-R]OGS and CINECA under HPC-TRES program award number 2020-0

Daily gridded datasets of snow depth and snow water equivalent for the Iberian Peninsula from 1980 to 2014

International audienceWe present snow observations and a validated daily gridded snowpack dataset that was simulated from downscaled reanalysis of data for the Iberian Peninsula. The Iberian Peninsula has long-lasting seasonal snowpacks in its different mountain ranges, and winter snowfall occurs in most of its area. However, there are only limited direct observations of snow depth (SD) and snow water equivalent (SWE), making it difficult to analyze snow dynamics and the spatiotemporal patterns of snowfall. We used meteorological data from downscaled reanalyses as input of a physically based snow energy balance model to simulate SWE and SD over the Iberian Peninsula from 1980 to 2014. More specifically, the ERA-Interim reanalysis was downscaled to 10 km × 10 km resolution using the Weather Research and Forecasting (WRF) model. The WRF outputs were used directly, or as input to other submodels, to obtain data needed to drive the Factorial Snow Model (FSM). We used lapse rate coefficients and hygrobarometric adjustments to simulate snow series at 100 m elevations bands for each 10 km × 10 km grid cell in the Iberian Peninsula. The snow series were validated using data from MODIS satellite sensor and ground observations. The overall simulated snow series accurately reproduced the interannual variability of snowpack and the spatial variability of snow accumulation and melting, even in very complex topographic terrains. Thus, the presented dataset may be useful for many applications, including land management, hydrometeorological studies, phenology of flora and fauna, winter tourism, and risk management. The data presented here are freely available for download from Zenodo (https://doi.org/10.5281/zenodo.854618). This paper fully describes the work flow, data validation, uncertainty assessment, and possible applications and limitations of the database