Ana Andreu

University of Córdoba | UCO · Andalusian Institute for Earth System Research

In Mediterranean oak-savannas (known as dehesas in Spain), it is important to better understand the interactions between vegetation structure and local climate regulation at scales relevant to farm management and the dominant hydrological regime. This study evaluated the water use patterns of dehesa vegetation patches (open grasslands, lowland gras...

As the availability of satellite and airborne thermal infrared remote sensing (TIR-RS) data increases and their spatial, temporal, and spectral resolutions improve, researchers are finding diverse applications for TIR-RS measurements. TIR-RS is now commonly applied in regional- and continental-scale analyses, such as those focused on fire and surfa...

La dehesa es un ecosistema Mediterráneo tipo sabana para cuya conservación es importante comprender mejor las interacciones entre la estructura de la vegetación y la regulación de los microclimas, a escalas relevantes tanto para la gestión agrícola como para el régimen hidrológico dominante. En este trabajo se evalúan los patrones de uso de agua de...

It is well documented that energy balance and other remote sensing-based evapotranspiration (ET) models face greater uncertainty over water-limited tree-grass ecosystems (TGEs), representing nearly 1/6th of the global land surface. Their dual vegetation strata, the grass dominated understory and tree dominated overstory, make for distinct structura...

In open-canopy ecosystems, thermal imaging affords an unprecedented opportunity to resolve concurrent temperatures of overstory vegetation, understory vegetation, and soil across space and time. This simultaneous view of ecosystem components promises a holistic understanding of ecosystem energy status, defines diverse thermal niches, and can provid...

Mediterranean oak savanna is composed of a mixture of scattered oak trees, crops, pasture, and shrubs. It is the most widespread agroforestry landscape in Europe, and its conservation faces multiple threats including water scarcity, which has been exacerbated by global warming and greater climate variability. Evapotranspiration (ET) can be used as...

Water resources and their properties highly vary in both space and time and their observations have high uncertainties. The characterization of this variability requires long-term spatially distributed observations, that allow the recognition of spatio-temporal patterns and changes. Unlike other engineering activities that typically can be satisfie...

Drought is a devastating natural hazard that is difficult to define, detect and quantify. The increased availability of both meteorological and remotely sensed data provides an opportunity to develop new methods to identify drought conditions and characterize how drought changes over space and time. In this paper, we applied the surface energy bala...

The vegetation index (VI)-reference evapotranspiration (ETo) method incorporates the estimation of basal crop coefficients from spectral VIs into the FAO56 guidelines for computing crop evapotranspiration (ET). Previous research pointed to the possibility of the differential spectral response of some Mediterranean crops, specifically olive trees. T...

Abstract. Drought is a devastating natural hazard, difficult to define, detect and quantify. Global meteorological data and remote sensing products present new opportunities to characterize drought in an objective way, and to extend this analysis in space and time. In this paper, we applied the surface energy balance model SEBS (Surface Energy Bala...

The use of soil moisture (SM) measurements from satellites has grown in recent years, fostering the development of new products at high resolution. This opens the possibility of using them for certain applications that were normally carried out using in situ data. We investigated this hypothesis through two main analyses using two high-resolution s...

Mediterranean oak savannas (known as dehesas in Spain) are exposed to numerous threats from natural and economic causes. A close monitoring of the use of water resources and the status of the vegetation in these ecosystems can be useful tools for maintaining the production of ecological services. This study explores the estimation of evapotranspira...

Savannas are among the most productive biomes of Africa, where they comprise half of its surface. They support wildlife, livestock, rangelands, crops, and livelihoods, playing an important socioeconomic role in rural areas. These water-limited ecosystems with seasonal water availability are highly sensitive to changes in both climate conditions, an...

Mediterranean oak savanna, or dehesa, is the most characteristic agroforestry system of the Iberian Peninsula. It is composed by a mosaic of widely-spaced oak trees (primarily Quercus Ilex L. and Quercus Suber L.), crops, pasture and shrubs. In the last decades, this ecosystem has faced numerous threats, such as low profitability, an intensificatio...

Savannas are among the most variable, complex and extensive biomes on Earth, supporting livestock and rural livelihoods. These water-limited ecosystems are highly sensitive to changes in both climatic conditions, and land-use/management practices. The integration of Earth Observation (EO) data into process-based land models enables monitoring ecosy...

Dehesas are highly valuable agro-forestry ecosystems, widely distributed over Mediterranean-type climate areas, which play a key role in rural development, basing their productivity on a sustainable use of multiple resources (crops, livestock, wildlife, etc.). The information derived from remote sensing based models addressing ecosystem water consu...

p>The objective of this work is to provide new insights about the effect of soil water deficit on the vegetation of Mediterranean oak savanna. The evolution of evapotranspiration (ET) and vegetation water stress over this ecosystem, in the Iberian Peninsula, has been monitored for fifteen years through the application of a remote sensing thermal-ba...

More than half of the human population currently lives in urban areas and according to the United Nations, cities will be the living space of an additional 2.5 billion people by the year 2050 (UN, 2015b). The proportion and speed of this urban growth increase the pressure on water resources, and this is often seen negatively. However, this challeng...

Savannas are among Africa’s most productive multifunctional landscape – supporting wildlife, livestock, crops, and livelihoods – but experience frequent droughts, aggravated by climate change and other human-induced changes. To maintain ecosystem productivity while ensuring food security, we need to rely on an integrated management and monitoring o...

The integration of currently available satellite data into surface energy balance models can provide estimates of evapotranspiration (ET) with spatial and temporal resolutions determined by sensor characteristics. The use of data fusion techniques may increase the temporal resolution of these estimates using multiple satellites, providing a more fr...

Monitoring savanna water use and water stress from local to regional scales supporting rangeland management (Pilot experience in Kruger National Park, South Africa)

Remote Sensing of water management in Kruger Park, South Africa.

Savanna is among Africa's most productive landscapes, supporting livestock and rural livelihoods. Droughts and erratic rainfall patterns across large parts of Africa results in water-limited environments, sensitive to climatic conditions, environmental changes (i.e. invasive species) and land management practices, jeopardizing this ecosystem’s prod...

The regular monitoring of the evapotranspiration rates and their links with vegetation conditions and soil moisture may support management and hydrological planning leading to reduce the economic and environmental vulnerability of complex water-controlled Mediterranean ecosystems. In this work, the monitoring of water use over a basin with a predom...

The integration of remotely sensed data into models for estimating evapotranspiration (ET) has increased significantly in recent years, allowing the extension of these models application from point to regional scale. Remote sensors provide distributed information about the status of vegetation and allow for a regular monitoring of water consumption...

The integration of remotely sensed data into models for estimating evapotranspiration (ET) has increased significantly in recent years, allowing the extension of these models application from point to regional scale. Remote sensors provide distributed information about the status of vegetation and allow for a regular monitoring of water consumption...

An intercomparison between the Energy Water Balance model (FEST-EWB) and the Two-Source Energy Balance model (TSEB) is performed over a heterogeneous agricultural area. TSEB is a residual model which uses Land Surface Temperature (LST) from remote sensing as a main input parameter so that energy fluxes are computed instantaneously at the time of da...

A very simple remote sensing-based model for water use monitoring is presented. The model acronym DATTUTDUT (Deriving Atmosphere Turbulent Transport Useful To Dummies Using Temperature) is a Dutch word which loosely translates as “it’s unbelievable that it works”. DATTUTDUT is fully automated and only requires a surface temperature map, making it s...

A two-source model for deriving surface energy fluxes and their soil and canopy components was evaluated using multi-angle airborne observations. In the original formulation (TSEB1), a single temperature observation, Priestley–Taylor parameterization and the vegetation fraction are used to derive the component fluxes. When temperature observations...

The REFLEX 2012 campaign was initiated as part of a training course on the organization of an airborne campaign to support advancement of the understanding of land-atmosphere interaction processes. This article describes the campaign, its objectives and observations, remote as well as in situ. The observations took place at the experimental Las Tie...

The dehesa, the most widespread agroforest ecosystem in Europe (≍ 3 million ha), is recognized as an example of sustainable land use and for its importance in rural economy. It is characterized by widely-spaced oak trees (mostly Quercus Ilex L.), combined with crops, pasture and shrubs in the sub-canopy region. The estimation of the ecosystem evapo...

The Dehesa is the most widespread agroforestry land-use system in Europe, covering more than 3 million hectares in the Iberian Peninsula and Greece (Grove and Rackham, 2001; Papanastasis, 2004). It is an agro-silvo-pastural ecosystem consisting of widely-spaced oak trees (mostly Quercus ilex L.), combined with crops, pasture and Mediterranean shrub...

Evapotranspiration (ET) is a critical variable in hydrological processes and an accurate estimation of the rate of evapotranspiration is required if we wish to apply integrated management procedures to water resources. This study offers new insights into remote sensing-based models that estimate ET at basin scale, evaluating the combination of a su...

A two-source energy balance model that separates surface fluxes of the soil and canopy was applied to a drip-irrigated vineyard in central Spain, using a series of nine Landsat-5 images acquired during the summer of 2007. The model partitions the available energy, using surface radiometric temperatures to constrain the sensible heat flux, and compu...

The integrated water resource management required to face the water scarcity situation in semiarid regions relies on the ability to obtain accurate information about the use of water by crops and natural vegetation. Thermal remote sensing provides key data about the vegetation water status. The integration of this remotely sensed data into water an...