SIGPAC y series multitemporales LANSAT 15 TM como estrategia híbrida de clasificación de usos de suelo para aplicaciones hidrológicas

El objetivo de este trabajo consiste en la obtención de un mapa de usos y coberturas de suelo para su integración en un modelo hidrológico de balance de agua a lo largo de 2009. Los resultados de dicha aplicación (evapotranspiración, humedad de suelo, necesidades de riego) se obtienen a escala de parcela, con escala temporal diaria y contemplando los usos y coberturas más frecuentes en la zona. La herramienta diseñada para aplicar el modelo (HidroMORE, Modelo Hidrológico de Estimación de Recarga y Evapotranspiración) proporciona los resultados en forma de mapa imagen. Con este fin, se presenta una alternativa híbrida de clasificación consistente en la combinación de la base de datos vectorial del Sistema de Información Geográfica de Parcelas Agrícolas (SIGPAC), junto con una serie multitemporal de imágenes Landsat 5 TM (Thematic Mapper) del año 2009. El primero aporta la definición parcelaria, mientras que la segunda provee la información suficiente para resolver clases poco definidas en el SIGPAC, especialmente la categoría ‘tierra arable’. Se utilizaron metodologías de teledetección como la clasificación, la segmentación multitemporal y el NDVI (Normalized Difference Vegetation Index), junto con herramientas SIG. El método propuesto supuso una mejora global de la precisión respecto a un método de clasificación supervisada convencional del 20% para la zona de estudio en 2009, y con un coste operacional muy bajo.The aim of this work consists on retrieving a land use-land cover map in order to integrate it in a water balance model along 2009. The results of this application, i.e., evapotranspiration, soil moisture, irrigation rates, are obtained at field scale, in a daily basis, and over the most representative agricultural uses. The model is implemented in a computerized tool, HidroMORE, which provides image maps of the results. A hybrid alternative of classification is presented for such hydrological application. It consisted in a combination of the vectorial database from the Spanish Geographic Information System for Agricultural Plots (SIGPAC) and a Landsat 5 TM multitemporal series of images for the year of study. The SIGPAC affords the spatial shape of the plots, whereas the images allow the segmentation of some ambiguous categories, i.e., ‘agricultural plots’. Remote sensing techniques (classification, segmentation, and NDVI, Normalized Difference Vegetation Index) were used, as well as GIS tools. The proposed method improved by 20% the global accuracy comparing to a typical supervised classification in the study area along 2009, while the computational cost is low

Necesidades de agua de riego en una explotación comercial de almendro mediante teledetección

La superficie dedicada al cultivo del almendro (Prunus dulcis) en regadío se ha duplicado en España en los últimos 5 años. La alta respuesta del rendimiento de este cultivo a la cantidad de agua aplicada junto con su elevada rentabilidad ha propiciado que actualmente el cultivo del almendro se convierta en una alternativa al cultivo de cereales y otros leñosos en muchas zonas del territorio nacional. No obstante, la expansión del cultivo en zonas con escasez de agua hace necesario el desarrollo y la aplicación de herramientas que permitan conocer sus necesidades de agua con la suficiente precisión, resolución espacial y temporal, con el objetivo de optimizar los recursos hídricos, realizar una gestión más rentable y sostenible con el entorno. De esta manera, las series temporales de imágenes de NDVI de satélite surgen como una herramienta valiosa que permiten caracterizar la evolución espacial y temporal de la cubierta vegetal y estimar con precisión la evolución del coeficiente de cultivo a lo largo del ciclo de crecimiento siguiendo las relaciones establecidas en la literatura científica. El objetivo del presente estudio es determinar la evapotranspiración del cultivo del almendro y sus necesidades de agua de riego a través de la implementación del modelo de balance diario de agua en el suelo explorado por las raíces descrito en el manual de FAO 56 y asistido por teledetección. La metodología propuesta integra el coeficiente basal de cultivo (Kcb) derivado de la serie temporal de imágenes de satélite en el balance de agua. Dicha metodología está bien documentada en la literatura científica para otros cultivos, aunque permanece casi inexplorada y con escasa experiencia previa para el cultivo del almendro. El estudio se ha realizado en una explotación de almendro con riego localizado situada en el término municipal de Abarán (provincia de Murcia) durante la campaña 2019. Las necesidades de agua de riego estimadas con el modelo propuesto son evaluadas frente a datos reales de riego aplicados por el agricultor. Los resultados obtenidos revelan el desempeño de la metodología propuesta para estimar con precisión las necesidades de agua de riego del cultivo del almendro a lo largo de la campaña de estudio, capturando diferencias en los requerimientos de agua del cultivo entre las parcelas analizadas. La aplicación de la metodología en situaciones reales permite al agricultor ajustar el suministro de agua a las demandas del cultivo, y ampliar su conocimiento sobre el uso del agua realizado en la explotación. Esta información resulta de gran utilidad para la toma de decisiones orientadas a la mejora de la planificación de riegos, elaboración de estrategias de riego deficitario controlado (RDC) y a una optimización de la gestión y uso de los recursos hídricos

The Political Economy of Water Policy Design and Implementation in the Jucar Basin, Spain

Water scarcity has intensified conflicts between regions and interest groups for the use of water resources. Water policies have been implemented worldwide to face with water stress; however, existence of opposite interest between water users together with differences in their political power hinder the effectiveness of the water policy reform. A better understanding of users’ behavior is necessary to avoid the failure of water policies and the intensification of water scarcity problems and water conflicts. This paper empirically examines the perception of interest group about the implementation of different water policies to deal with water scarcity, and also their proactive involvement, or lobbying, with water organizations. We have conducted a survey in a water stressed basin in Southeastern Spain (Jucar River Basin) to analyze interest group opinions regarding water institutions’ performance and management; and the cost and benefits from group influence or lobbying on policy makers. The results highlight the existence of notably differences between the preferred measure to face with water scarcity together with sizable divergences in the active lobbying capacity of the interest groups depending on the size of the group, the specific basin location (upstream or downstream), and group characteristics.This Project was possible because the support of the project INIA RTA2014-00050-00-00. Ariel Dinar would like to acknowledge support by the Multistate Hatch Project W3190- Management and Policy Challenges in a Water-Scarce WorldPublishe

Monitoring 10-m LST from the Combination MODIS/Sentinel-2, Validation in a High Contrast Semi-Arid Agroecosystem

Downscaling techniques offer a solution to the lack of high-resolution satellite Thermal InfraRed (TIR) data and can bridge the gap until operational TIR missions accomplishing spatio-temporal requirements are available. These techniques are generally based on the Visible Near InfraRed (VNIR)-TIR variable relations at a coarse spatial resolution, and the assumption that the relationship between spectral bands is independent of the spatial resolution. In this work, we adopted a previous downscaling method and introduced some adjustments to the original formulation to improve the model performance. Maps of Land Surface Temperature (LST) with 10-m spatial resolution were obtained as output from the combination of MODIS/Sentinel-2 images. An experiment was conducted in an agricultural area located in the Barrax test site, Spain (39°03′35″ N, 2°06′ W), for the summer of 2018. Ground measurements of LST transects collocated with the MODIS overpasses were used for a robust local validation of the downscaling approach. Data from 6 different dates were available, covering a variety of croplands and surface conditions, with LST values ranging 300-325 K. Differences within ±4.0 K were observed between measured and modeled temperatures, with an average estimation error of ±2.2 K and a systematic deviation of 0.2 K for the full ground dataset. A further cross-validation of the disaggregated 10-m LST products was conducted using an additional set of Landsat-7/ETM+ images. A similar uncertainty of ±2.0 K was obtained as an average. These results are encouraging for the adaptation of this methodology to the tandem Sentinel-3/Sentinel-2, and are promising since the 10-m pixel size, together with the 3-5 days revisit frequency of Sentinel-2 satellites can fulfill the LST input requirements of the surface energy balance methods for a variety of hydrological, climatological or agricultural applications. However, certain limitations to capture the variability of extreme LST, or in recently sprinkler irrigated fields, claim the necessity to explore the implementation of soil moisture or vegetation indices sensitive to soil water content as inputs in the downscaling approach. The ground LST dataset introduced in this paper will be of great value for further refinements and assessments

A simulation of soil water content based on remote sensing in a semi-arid Mediterranean agricultural landscape

This paper shows the application of a water balance based on remote sensing that integrated a Landsat 5 series from 2009 in an area of 1,300 km2 in the Duero Basin (Spain). The objective was to simulate the daily soil water content (SWC), actual evapotranspiration, deep percolation and irrigation rates. The accuracy of the application is tested in a semi-arid Mediterranean agricultural landscape with crops over natural conditions. The results of the simulated SWC were compared against 19 in situ stations of the Soil Moisture Measurement Stations Network (REMEDHUS), in order to check the feasibility and accuracy of the application. The theoretical basis of the application was the FAO56 calculation assisted by remotely sensed imagery. The basal crop coefficient (Kcb), as well as other parameters of the calculation came from the remote reflectance of the images. This approach was implemented in the computerized tool HIDROMORE+, which integrates various spatial databases. The comparison of simulated and observed values (at different depths and different land uses) showed a good global agreement for the area (R2=0.92, RMSE=0.031 m3 m-3, and bias=-0.027 m3 m-3). The land uses better described were rainfed cereals (R2=0.86, RMSE=0.030 m3 m-3, and bias=-0.025 m3 m-3) and vineyards (R2=0.86, RMSE=0.016 m3 m-3, and bias=-0.013 m3 m-3). In general, an underestimation of the soil water content is noticed, more pronounced into the root zone than at surface layer. The final aim was to convert the application into a hydrological tool available for agricultural water management