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The Norwegian Centre for Climate Services (NCCS) has developed a production chain for climate information with the aim of delivering a knowledge base for climate change adaptation suitable for use by planners at various administrative levels in Norway. This process consists of two main steps: First, climate and hydrological projections are produced at a local scale (1 × 1 km resolution) using available results from global and regional climate models (GCMs and RCMs). In a second step, climate factsheets with abridged information relevant for individual counties in Norway have been co-produced with users and county authorities. Projections were produced by using a climate–hydrological modeling chain driven by downscaled simulations from 10 GCM–RCM combinations and two climate scenarios in which temperature and precipitation were first downscaled and bias-adjusted to a 1 × 1 km resolution. Bias-adjustment was necessary, partly due to biases in the RCMs. These results were published in the Norwegian climate assessment report “Climate in Norway 2100.” The results have then been disseminated through various formats, such as reports, dataportals, visualizations and factsheets (available at https://klimaservicesenter.no/). NCCS has issued climate factsheets for 17 counties in Norway and Svalbard. The county-wise climate factsheets have become the most extensive product issued by NCCS. A challenge when developing information about climate change for use in adaptation is the issue of uncertainty, and the trade-off between robustness vs. precision in the numerical values given should guide the dissemination of climate information. Based on our experiences, we also recommend that climate information is developed in collaboration with users because this ensures that it will be understood by a wider audience. Most climate-related challenges for infrastructure are related to extreme events. For technical applications in Norway, climate change allowances are now available for heavy precipitation, floods, and storm surges as a tool for design analyses of buildings and infrastructure. This paper describes the production chain for the presently available climate projections following the release of IPCC AR5 (CMIP5), our experiences of the dissemination process, as well as our plans for further development of the next national climate assessment report based on IPCC AR6 (CMIP6).

An ensemble of ten EURO-CORDEX GCM/RCM simulations, each representing two alternative emission pathways (RCP4.5 and RCP8.5), were bias-corrected using an empirical quantile mapping method. These corrected datasets covering the period 1971-2100 were then forced with a spatially distributed, gridded version of the HBV model to generate daily time series of different hydrological components. These high-resolution climate and hydrological projections, despite their limitations, represent a valuable data source for different types of climate impact studies at a national and local scale.

Denne sluttrapporten oppsummerer resultater og leveranser fra prosjektet 81057. Prosjektet har hatt som fokus å videreutvikle flomvarslingens modellrammeverk og forbedre de hydrologiske modellprognosene så treffsikkerheten øker og presisjonen kan angis. Prosjektet har også vært opptatt av at det store og mangeartede datamaterialet som tilflyter flomvarslingstjenesten skal tilgjengeliggjøres og tas i bruk, slik at prognosegrunnlaget blir bredest mulig

Impacts of reservoirs and irrigation water withdrawals on continental surface water fluxes are studied within the framework of the Variable Infiltration Capacity (VIC) model for a part of North America, and for Asia. A reservoir model, designed for continental‐scale simulations, is developed and implemented in the VIC model. The model successfully simulates irrigation water requirements, and captures the main effects of reservoir operations and irrigation water withdrawals on surface water fluxes, although consumptive irrigation water use is somewhat underestimated. For the North American region, simulated irrigation water requirements and consumptive irrigation water uses are 191 and 98 km3year−1, while the corresponding numbers for the Asian region are 810 and 509 km3year−1, respectively. The consumptive uses represent a decrease in river discharge of 4.2 percent for the North American region, and 2.8 percent for the Asian region. The largest monthly decrease is about 30 percent, for the area draining the Western USA in June. The maximum monthly increase in streamflow (28 percent) is in March for the Asian Arctic region.

Global-scale hydrological models are routinely used to assess water scarcity, flood hazards and droughts worldwide. Recent efforts to incorporate anthropogenic activities in these models have enabled more realistic comparisons with observations. Here we evaluate simulations from an ensemble of six models participating in the second phase of the Inter-Sectoral Impact Model Inter-comparison Project (ISIMIP2a). We simulate monthly runoff in 40 catchments, spatially distributed across eight global hydrobelts. The performance of each model and the ensemble mean is examined with respect to their ability to replicate observed mean and extreme runoff under human-influenced conditions. Application of a novel integrated evaluation metric to quantify the models' ability to simulate timeseries of monthly runoff suggests that the models generally perform better in the wetter equatorial and northern hydrobelts than in drier southern hydrobelts. When model outputs are temporally aggregated to assess mean annual and extreme runoff, the models perform better. Nevertheless, we find a general trend in the majority of models towards the overestimation of mean annual runoff and all indicators of upper and lower extreme runoff. The models struggle to capture the timing of the seasonal cycle, particularly in northern hydrobelts, while in southern hydrobelts the models struggle to reproduce the magnitude of the seasonal cycle. It is noteworthy that over all hydrological indicators, the ensemble mean fails to perform better than any individual model—a finding that challenges the commonly held perception that model ensemble estimates deliver superior performance over individual models. The study highlights the need for continued model development and improvement. It also suggests that caution should be taken when summarising the simulations from a model ensemble based upon its mean output., Environmental Research Letters, 13 (6), ISSN:1748-9326, ISSN:1748-9318

Resultater fra 98 nedbørfelt simulert med HBV, ODM og DDD modellen er vurdert. DDD har noe bedre treff og færre falske alarmer enn HBV og ODM for alternativene der det ikke tillates en tidsforskyvning mellom observerte og simulerte flomtopper. Generelt scorer modellene bedre når man tillater en tidsforskjell i flomtoppen på et døgn, og i dette tilfellet er resultatene fra HBV litt bedre enn de to andre modellsystemene. Analysene indikerer også at det er rom for forbedringer når det gjelder modellenes evne til å treffe flomtoppene.