Comparing surface-soil moisture from the SMOS mission and the ORCHIDEE land-surface model over the Iberian Peninsula

The aim of this study is to compare the surface soil moisture (SSM) retrieved from ESA's Soil Moisture and Ocean Salinity mission (SMOS) with the output of the ORCHIDEE (ORganising Carbon and Hydrology In Dynamic EcosystEm) land surface model forced with two distinct atmospheric data sets for the period 2010 to 2012. The comparison methodology is first established over the REMEDHUS (Red de Estaciones de MEDición de la Humedad def Suelo) soil moisture measurement network, a 30 by 40. km catchment located in the central part of the Duero basin, then extended to the whole Iberian Peninsula (IP). The temporal correlation between the in-situ, remotely sensed and modelled SSM are satisfactory (r. >. 0.8). The correlation between remotely sensed and modelled SSM also holds when computed over the IP. Still, by using spectral analysis techniques, important disagreements in the effective inertia of the corresponding moisture reservoir are found. This is reflected in the spatial correlation over the IP between SMOS and ORCHIDEE SSM estimates, which is poor (¿. ~. 0.3). A single value decomposition (SVD) analysis of rainfall and SSM shows that the co-varying patterns of these variables are in reasonable agreement between both products. Moreover the first three SVD soil moisture patterns explain over 80% of the SSM variance simulated by the model while the explained fraction is only 52% of the remotely sensed values. These results suggest that the rainfall-driven soil moisture variability may not account for the poor spatial correlation between SMOS and ORCHIDEE products.Peer ReviewedPostprint (published version

Future Projections of Water Scarcity in the Danube River Basin Due to Land Use, Water Demand and Climate Change

This paper presents a state-of-the-art integrated model assessment to estimate the impacts of the 2°C global mean temperature increase and the 2061-2090 warming period on water scarcity in the Danube River Basin under the RCP8.5 scenario. The Water Exploitation Index Plus (WEI+) is used to calculate changes in both spatial extent and people exposed to water scarcity due to land use, water demand, population and climate change. Despite model and data uncertainties, the combined effects of projected land use, water demand and climate change show a decrease in the number of people exposed to water scarcity during the 2°C warming period and an increase in the 2061-2090 period in the Danube River Basin. However, the projected population change results in a decrease of exposed people in both warming periods. Regions with population growth, in the northwestern part of the Danube River Basin experience low water scarcity or a decrease in water scarcity. The largest number of people vulnerable to water scarcity within the Danube River Basin are living in the Great Morava, Bulgarian Danube and Romanian Danube. There, the combined effects of land use, water demand and climate change exacerbate already existing water scarce areas during the 2°C warming period and towards the end of the century new water scarce areas are created. Although less critical during the 2°C warming period, adjacent regions such as the Tisza, Middle Danube and Siret-Prut are susceptible to experience similar exposure to water scarcity within the 2061-2090 period. Climate change is the most important driver for the increase in water scarcity in these regions, but the strengthening effect of water demand (energy sector) and dampening effect of land use change (urbanization) does play a role as well. Therefore, while preparing for times of increased pressures on the water supply it would be advisable for several economic sectors to explore and implement water efficiency measures

Water scenarios for the Danube River Basin: Elements for the assessment of the Danube agriculture-energy-water nexus

This report provides background material for the identification and elicitation of scenarios relevant for the futures of the agriculture-energy-ecosystems-water nexus in the Danube region. We present a summary of the regional climate scenarios available as input for water resources simulations, and the consequent long term average water balance figures estimated using a Budyko framework. Then we introduce the LUISA model for the simulation of land use-related variables in the region. Finally, we include a contribution by a water expert from the Danube region, presenting an initial reasoning on important elements to be addressed in scenario simulations. This report is intended as a reader for water professionals, stakeholders and decision makers in the Danube region, in order to stimulate the foresight of scenarios worth being simulated with JRC models, so to further our understanding of the water-energy-agriculture-ecosystems nexus and its management in the mid- and long-term.JRC.H.1-Water Resource

Comparison of measured brightness temperatures from SMOS with modelled ones from ORCHIDEE and H-TESSEL over the Iberian Peninsula

L-band radiometry is considered to be one of the most suitable techniques to estimate surface soil moisture (SSM) by means of remote sensing. Brightness temperatures are key in this process, as they are the main input in the retrieval algorithm which yields SSM estimates. The work exposed compares brightness temperatures measured by the SMOS mission to two different sets of modelled ones, over the Iberian Peninsula from 2010 to 2012. The two modelled sets were estimated using a radiative transfer model and state variables from two land-surface models: (i) ORCHIDEE and (ii) H-TESSEL. The radiative transfer model used is the CMEM. Measured and modelled brightness temperatures show a good agreement in their temporal evolution, but their spatial structures are not consistent. An empirical orthogonal function analysis of the brightness temperature's error identifies a dominant structure over the south-west of the Iberian Peninsula which evolves during the year and is maximum in autumn and winter. Hypotheses concerning forcing-induced biases and assumptions made in the radiative transfer model are analysed to explain this inconsistency, but no candidate is found to be responsible for the weak spatial correlations at the moment. Further hypotheses are proposed and will be explored in a forthcoming paper. The analysis of spatial inconsistencies between modelled and measured TBs is important, as these can affect the estimation of geophysical variables and TB assimilation in operational models, as well as result in misleading validation studies

Impact of a changing climate, land use, and water usage on water resources in the Danube river basin

Impact of a changing climate, land use, and water usage on water resources in the Danube river basinJRC.D.2-Water and Marine Resource

Climate change and Europe’s water resources

In addition to the already existing pressure on our freshwater resources, climate change may further decrease water availability. In this study, projections of future water resources, due to climate change, land use change and changes in water consumption have been assessed using JRC’s LISFLOOD water resources model. The results presented are based on 11 climate models which project current and future climate under two Representative Concentration Pathways (RCPs): RCP4.5 and RCP 8.5 emission scenario. RCP4.5 may be viewed as a moderate-emissions-mitigation-policy scenario and RCP8.5 as a high-end emissions scenario. A 30-year window around the year that global warming reaches 1.5oC, 2oC and 3oC above preindustrial temperature has been analysed and compared to the 1981-2010 control climate window (baseline). The 1.5°C and 2°C warming scenarios are explicitly considered in the Paris Agreement, while a 3°C global warming is a scenario that could be expected by the end of the 21st century if adequate mitigation strategies are not taken. First, we performed future projections without socio-economic developments to show the effect of climate change only. Next, an integrated assessment is performed including future changes in land use, water demand and population. This allows us to disentangle the effects of climate and socio-economic changes. In general, the climate projections reveal a typically North-South pattern across Europe for water availability. Overall, Southern European countries are projected to face decreasing water availability, particularly Spain, Portugal, Greece, Cyprus, Malta, Italy and Turkey. Central and Northern European countries show an increasing annual water availability.JRC.D.2-Water and Marine Resource

Assessing the effects of water saving measures on Europe's water resources: BLUE2 project - Freshwater quantity

Using JRC's LISFLOOD water resources model, the effect of four policy measures on Europe's water resources were investigated under current and future climate. The measures evaluated were increasing irrigation efficiency, urban water use efficiency, cooling water usage for energy production, and urban waste-water re-use for irrigation. The measures were evaluated following their current planned implementation (BAU) under the Water Framework Directive. Furthermore, an Maximum Feasible Technology scenario was investigated for all 4 measures. Increasing irrigation efficiency shows to have the largest effect on improving water resources, under current climate. Under future climate change however, the projected decreases in water availability in especially the Mediterranean are larger than the increases obtained with improving irrigation efficiency. This may indicate that an increased level of ambition in water efficiency measures is required to reduce the impact of climate change on water resources.JRC.D.2-Water and Marine Resource

Impact of a changing climate, land use, and water usage on Europe’s water resources: A model simulation study

In this work, an assessment of the impacts of climate change on Europe’s water resources has been performed, focusing on the effects of 2°C warming. Climate projections from 1981-2100 were run through a distributed hydrological model assuming constant land use and water demand (year 2006). In this study, the 2°C warming period of five climate change projections was analysed. As a consequence of a 2 degree climate change, it is expected that - except for the Mediterranean region - precipitation will increase in most parts of Europe with the highest values over the Alps and Eastern Europe. These increases in precipitation are most likely linked to the increase in temperature which triggers more convective storms in the summer months. The observed consequences of a 2 degree climate change for the river flow and extreme events – floods and droughts - are: • The annual median river discharge shows an increase in most parts of Europe, except for the Mediterranean area where a decrease in flow is projected in all four seasons. • As a consequence of climate change, extreme peak discharges are projected to increase in almost every part of Europe, even the Mediterranean. The highest increases in flood hazards are found in the summer months for the inland countries whereas coastal zones and parts of Scandinavia show a decrease in floods. These increases are probably linked again to the increase in temperature which triggers more convective storms with a higher probability of floods. Especially urban areas near larger rivers might need more attention to flood risk management and planning, due to projections of growth of urban areas and increased flood hazard. • Streamflow droughts will become more severe in the summer season mainly for the Mediterranean region (Spain, Portugal, Greece). This might have an impact for cooling water intake for industrial and energy production activities, irrigation water availability, critical environmental flow conditions, as well as hydropower potential. • According the climate change projections the most extreme events are projected to occur in summer with an increase in flood risk in the eastern part of Europe (e.g. Poland) and the Baltic countries and extreme droughts in the Mediterranean region. These projected future changes in the hydrological cycle are directly reflected in the water resources indicators. Especially the southern European countries are projected to face increased water shortages: • Climate change projections lead to an increase in the number of days per year that river flows are lower than a critical minimum in the Mediterranean regions and a decrease in the northern latitudes. Especially Spain and Portugal face increased low flow conditions. • The climate change projections lead to a decrease of groundwater resources in the southern European countries and an increase for the northern countries. Further over-abstraction of groundwater in southern European countries – beyond renewable capacity – might lead to critical deep groundwater levels and increased pumping costs to extract the water for use at the surface. • Soil moisture stress conditions - which could reduce agricultural crop yields, are especially increasing under the 2oC warming scenario in the already stressed areas in the Mediterranean. Specific crop yield effects are described in the report on agriculture. - • The southern European regions with already a high current water consumption relative to water availability are projected to be most affected by a 2-degree warming due to a decrease in freshwater resources, and at the same time an increased need for irrigation water due to higher evaporative demands. • In the Mediterranean countries and especially in Spain the water resources situation will become more unsustainable. Inflowing upstream freshwater is also not sufficient to meet local water needs under a 2 degree warming. • For eastern Europe, the projections indicate that some regions will rely to a reduced extent on upstream inflow to meet their local water demands. Policy implications: • Especially in the Mediterranean part of Europe, water savings will be essential to adapt to the decreasing overall water availability; savings could take place to increasing irrigation efficiency, sub-optimal or deficit irrigation strategies, efficiency increases in cooling processes in industry and energy production, public water savings, a better intra-annual management of water resources in a basin (e.g. storing winter water in hydropower reservoirs for irrigation water use in summer. Increased synergies between the water and agricultural policies are needed. • To raise awareness for the importance of water, setting a reasonable price on water will be an essential incentive for users for water savings. As long as water is either free of charge or to cheap, users will likely not be urged for savings. • A better control on and prevention of illegal abstractions is needed to prevent over-abstraction of groundwater in a number of European regions. A better reporting of water abstractions does help the monitoring of water resources as well. • Given the expected increase in flood hazard, especially in the urbanised areas – which in many cases are expected for further grow until 2050 according to JRC’s LUISA projections – flood risk management, prevention and adaptation to floods will become an even bigger issue.JRC.D.2-Water and Marine Resource