Impacts of climate change on European hydrology at 1.5, 2 and 3 degrees mean global warming above preindustrial level

Impacts of climate change at 1.5, 2 and 3 °C mean global warming above preindustrial level are investigated and compared for runoff, discharge and snowpack in Europe. Ensembles of climate projections representing each of the warming levels were assembled to describe the hydro-meteorological climate at 1.5, 2 and 3 °C. These ensembles were then used to force an ensemble of five hydrological models and changes to hydrological indicators were calculated. It is seen that there are clear changes in local impacts on evapotranspiration, mean, low and high runoff and snow water equivalent between a 1.5, 2 and 3 °C degree warmer world. In a warmer world, the hydrological impacts of climate change are more intense and spatially more extensive. Robust increases in runoff affect the Scandinavian mountains at 1.5 °C, but at 3 °C extend over most of Norway, Sweden and northern Poland. At 3 °C, Norway is affected by robust changes in all indicators. Decreases in mean annual runoff are seen only in Portugal at 1.5 °C warming, but at 3 °C warming, decreases to runoff are seen around the entire Iberian coast, the Balkan Coast and parts of the French coast. In affected parts of Europe, there is a distinct increase in the changes to mean, low and high runoff at 2 °C compared to 1.5 °C, strengthening the case for mitigation to lower levels of global warming. Between 2 and 3 °C, the changes in low and high runoff levels continue to increase, but the changes to mean runoff are less clear. Changes to discharge in Europe’s larger rivers are less distinct due to the lack of homogenous and robust changes across larger river catchments, with the exception of Scandinavia where discharges increase with warming level

Land Cover Change in the Okavango River Basin : Historical changes during the Angolan civil war, contributing causes and effects on water quality

The Okavango river flows from southern Angola, through the Kavango region of Namibia and into the Okavango Delta in Botswana. The recent peace in Angola hopefully marks the end of the intense suffering that the peoples of the river basin have endured, and the beginning of sustainable decision-making in the area. Informed decision-making however requires knowledge; and there is a need for, and a lack of knowledge regarding basin-wide land cover (LC) changes, and their causes, during the Angolan civil war in the basin. Furthermore, there is a need for, and a lack of knowledge on how expanding large-scale agriculture and urban growth along the Angola-Namibia border affects the water quality of the river. The aim of this study was therefore to develop a remote sensing method applicable to the basin (with scant ground-truth data availability) to carry out a systematic historic study of LC changes during the Angolan civil war, to apply the method to the basin, to relate these changes to major societal trends in the region, and to analyse potential impacts of expanding large-scale agriculture and urban growth on the water quality of the river along the Angola-Namibia border. A range of remote sensing methods to study historic LC changes in the basin were tried and evaluated against reference data collected during a field visit in Namibia in October 2005. Eventually, two methods were selected and applied to pre-processed Landsat MSS and ETM+ satellite image mosaics of 1973 and 2001 respectively: 1. a combined unsupervised classification and pattern-recognition change detection method providing quantified and geographically distributed binary LC class change trajectory information and, 2. an NDVI (Normalised Difference Vegetation Index) change detection method providing quantified and geographically distributed continuous information on degrees of change in vegetation vigour. In addition, available documents and people initiated in the basin conditions were consulted in the pursuit of discerning major societal trends that the basin had undergone during the Angolan civil war. Finally, concentrations of nutrients (total phosphorous & total nitrogen), bacteria (faecal coliforms & faecal streptococci), conductivity, total dissolved solids, dissolved oxygen, pH, temperature and Secchi depth were sampled at 11 locations upstream and downstream of large-scale agricultural facilities and an urban area during the aforementioned field visit. The nature, extent and geographical distribution of LC changes in the study area during the Angolan civil war were determined. The study area (150 922 km2) was the Angolan and Namibian parts of the basin. The results indicate that the vegetation vigour is dynamic and has decreased overall in the area, perhaps connected with precipitation differences between the years. However while the vigour decreased in the northwest, it increased in the northeast, and on more local scales the pattern was often more complex. With respect to migration out of Angola into Namibia, the LC changes followed expectations of more intense use in Namibia close to the border (0-5 km), but not at some distance (10-20 km), particularly east of Rundu. With respect to urbanisation, expectations of increased human impact locally were observed in e.g. Rundu, Menongue and Cuito Cuanavale. Road deterioration was also observed with Angolan urbanisation but some infrastructures appeared less damaged by the war. Some villages (e.g. Savitangaiala de Môma) seem to have been abandoned during the war so that the vegetation could regenerate, which was expected. But other villages (e.g. Techipeio) have not undergone the same vegetation regeneration suggesting they were not abandoned. The areal extent of large-scale agriculture increased 59% (26 km2) during the war, perhaps as a consequence of population growth. But the expansion was not nearly at par with the population growth of the Kavango region (320%), suggesting that a smaller proportion of the population relied on the large-scale agriculture for their subsistence in 2001 compared with 1973. No significant impacts were found from the large-scale agriculture and urbanisation on the water quality during the dry season of 2005. Total phosphorous concentrations (with range: 0.067-0.095 mg l-1) did vary significantly between locations (p=0.013) but locations upstream and downstream of large-scale agricultural facilities were not significantly different (p=0.5444). Neither did faecal coliforms (range: 23-63 counts per 100ml) nor faecal streptococci (range: 8-33 counts per 100ml) vary significantly between locations (p=0.332 and p=0.354 respectively). Thus the impact of Rundu and the extensive livestock farming along the border were not significant at this time. The Cuito river on the other hand significantly decreased both the conductivity (range: 27.2-49.7 μS cm-1, p<0.0001) and the total dissolved solid concentration (range: 12.7-23.4 mg l-1, p<0.0001) of the mainstream of the Okavango during the dry season. Land cover changes during the Angolan civil war, contributing causes and effects on water quality were studied in this research effort. Many of the obtained results can be used directly or with further application as a knowledge base for sustainable decision-making and management in the basin. Wisely used by institutions charged with that objective, the information can contribute to sustainable development and the ending of suffering and poverty for the benefit of the peoples of the Okavango and beyond

Övervakning av marknära ozon i Jönköpings län 2002-2004: resultat av mätningar med passiva ozonprovtagare under åren 2002-2004

Marknära ozon mäts i Jönköpings län sedan 1993 i syfte att värdera länet gentemot gällande regler till skydd för vegetation och människors hälsa som kan ta skada vid höga halter. Denna rapport redovisar framför allt resultat under perioden 2002-2004. Under dessa år har mätningar utförts vid två stationer sommartid och två stationer året runt med hjälp av passiva provtagare med en månatlig exponeringstid.Gällande riktlinjer, konvention, EG direktiv, miljökvalitetsnormer samt miljömål specificerar gränsvärden baserat på timmedelvärden. Eftersom stora timvariationer i ozonkoncentration finns kan inte länets månatliga mätningar jämföras på ett tillfredställande sätt gentemot dessa.Länets ozonhalter fluktuerar i en regelbunden cykel på årsbasis och har varken ökat eller minskat signifikant under perioden 1996-2004. Typiska halter för sommar respektive vinterhalvår är 60-90 mikrogram per kubikmeter samt 20-60 mikrogram per kubikmeter mätt som månadsmedelvärde. Halten där risk finns för skada på människors hälsa (120 mikrogram per kubikmeter) överskrids sällan medan gränsvärdet för skada på växtlighet (80 mikrogram per kubikmeter) överskrids regelbundet speciellt under april-juni. Om den relativt konstanta flerårstrenden håller i sig blir det svårt att nå generationsmålet rörande marknära ozon. Länets stationer skiljer sig inte signifikant åt (pRegionala inventeringsrapporter import från MDP 2015-05</p

Övervakning av marknära ozon i Jönköpings län 2002-2004: resultat av mätningar med passiva ozonprovtagare under åren 2002-2004

Marknära ozon mäts i Jönköpings län sedan 1993 i syfte att värdera länet gentemot gällande regler till skydd för vegetation och människors hälsa som kan ta skada vid höga halter. Denna rapport redovisar framför allt resultat under perioden 2002-2004. Under dessa år har mätningar utförts vid två stationer sommartid och två stationer året runt med hjälp av passiva provtagare med en månatlig exponeringstid.Gällande riktlinjer, konvention, EG direktiv, miljökvalitetsnormer samt miljömål specificerar gränsvärden baserat på timmedelvärden. Eftersom stora timvariationer i ozonkoncentration finns kan inte länets månatliga mätningar jämföras på ett tillfredställande sätt gentemot dessa.Länets ozonhalter fluktuerar i en regelbunden cykel på årsbasis och har varken ökat eller minskat signifikant under perioden 1996-2004. Typiska halter för sommar respektive vinterhalvår är 60-90 mikrogram per kubikmeter samt 20-60 mikrogram per kubikmeter mätt som månadsmedelvärde. Halten där risk finns för skada på människors hälsa (120 mikrogram per kubikmeter) överskrids sällan medan gränsvärdet för skada på växtlighet (80 mikrogram per kubikmeter) överskrids regelbundet speciellt under april-juni. Om den relativt konstanta flerårstrenden håller i sig blir det svårt att nå generationsmålet rörande marknära ozon. Länets stationer skiljer sig inte signifikant åt (pRegionala inventeringsrapporter import från MDP 2015-05</p

SIMULERING AV AVLOPPSFLÖDEN MED REGNDATAFRÅN MOBILTELEFONNÄT I STOCKHOLM : SIMULATING URBAN DRAINAGE FLOWS WITH RAINFALLDATA DERIVED FROM MOBILE PHONE NETWORKS INSTOCKHOLM

Municipal water utilities often only have access to a sparse network of rain gauges (ca. 10 in Stockholm).With sparse networks there is a risk to under- or overestimate sewer flow calculations when showers passbetween gauges, or when a spatially concentrated shower hits a gauge. Moreover, significant resourcesare required to keep the gauge network operational and reliable. Microwave links in telecommunicationnetworks can measure rainfall. The link network is much denser than the gauge network (here we study500 links in Stockholm), and is continuously maintained. Such links can hence be a valuable complementto gauges. This study initially compares link-based and gauge-based rainfall data. Generally, we observedlower maximum intensities for the links compared with the gauges: the shorter the duration the largerthe difference. Subsequently, we investigate how increasing network density and different types of raindata affects runoff, pipe flow and overflow in the sewer network using a hydraulic model. The resultsshow large differences in calculated flow between varying network densities (sometimes +/-80 %), andthat doubling the density often was sufficient during the seven studied rain events. Increasing the densityusing microwave links also gave better correspondence with measured inflow to the Henriksdal sewagetreatment plant. In summary, operational telecommunication networks have a large potential to complement rain gauges for water utilities.Kommunala VA-organisationer har ofta endast tillgång till ett glest nät med regnmätare (ett tiotal regnstationer i Stockholm). I glesa nät finns en risk att modellberäknade avloppsflöden under- eller överskattas när regnskurar passerar där det inte finns någon station, eller när en areamässigt liten skur träffaren station. Att hålla stationsnätet fungerande och tillförlitligt är dessutom en resurskrävande uppgift. Mikrovågslänkar i mobiltelefonnät kan mäta regn. Länknätverket är mycket tätare än regnstationerna(här undersöks 500 länkar i Stockholm), och underhålls kontinuerligt. Länkarna kan därför utgöra ettvärdefullt komplement till regnstationer. Studien jämför initialt regndata från länkar och regnstationer.Generellt observerades lägre maximala regnintensiteter för länkar än för regnstationer: ju kortare regnvaraktighet desto större skillnad. Studiens andra del undersöker hur en ökad täthet på och olika typer avregndata påverkar avrinning, flöden och bräddning i avloppsnätet m.h.a. en hydraulisk modell. Resultatenvisar på stora skillnader i beräknat flöde mellan nät med olika täthet (ibland +/-80 %), och att en dubblerad täthet var tillräcklig vid de sju studerade regntillfällena. Förtätning av nätet m.h.a. länkar gav ocksåen bättre överensstämmelse med uppmätt inflöde till Henriksdals reningsverk. Sammanfattningsvis haroperativa mobilnät stor potential att komplettera regnstationer i VA-verksamhet

Assessing robustness in global hydrological predictions by comparing modelling and Earth observations

International audienceHydrological modelling to support hypotheses on Earth system boundaries or the accelerating water crisis is nowadays done at the global scale, with difficulties associated to model uncertainties. Here we bring a robustness analysis of internal model variables as an additional tool for model evaluation using data from six Earth observation products and the global catchment model World-Wide HYPE in a comparative study. The assessment shows that: (i) variables have high agreement in mid-latitude temperate regions; (ii) the variables with higher agreement, and associated with good model performance in streamflow, were actual evapotranspiration, fractional snow cover and snow water equivalent; and (iii) changes in total water storage showed very poor agreement, probably due to an insufficient number of aquifers in the model set-up. We propose this procedure as a standard complementary method in global hydrological modelling, highlighting the importance of justifying models before using them for scenario analysis or water accounting