34 research outputs found
Streamflow forecast sensitivity to air temperature forecast calibration for 139 Norwegian catchments
In this study, we used meteorological ensemble forecasts
as input to hydrological models to quantify the uncertainty in forecasted
streamflow, with a particular focus on the effect of temperature forecast
calibration on the streamflow ensemble forecast skill. In catchments with
seasonal snow cover, snowmelt is an important flood-generating process.
Hence, high-quality air temperature data are important to accurately
forecast streamflows. The sensitivity of streamflow ensemble forecasts to
the calibration of temperature ensemble forecasts was investigated using
ensemble forecasts of temperature from the European Centre for Medium-Range Weather Forecasts (ECMWF) covering a period of nearly
3 years, from 1 March 2013 to 31 December 2015. To improve the skill and reduce
biases of the temperature ensembles, the Norwegian Meteorological Institute
(MET Norway) provided parameters for ensemble calibration, derived using a standard
quantile mapping method where HIRLAM, a high-resolution regional weather
prediction model, was used as reference. A lumped HBV (Hydrologiska Byråns Vattenbalansavdelning)
model, distributed on 10 elevation zones, was used to estimate the streamflow. The results show
that temperature ensemble calibration affected both temperature and
streamflow forecast skill, but differently depending on season and region.
We found a close to 1:1 relationship between temperature and streamflow
skill change for the spring season, whereas for autumn and winter large
temperature skill improvements were not reflected in the streamflow
forecasts to the same degree. This can be explained by streamflow being less
affected by subzero temperature improvements, which accounted for the
biggest temperature biases and corrections during autumn and winter. The
skill differs between regions. In particular, there is a cold bias in the
forecasted temperature during autumn and winter along the coast, enabling a
large improvement by calibration. The forecast skill was partly related to
elevation differences and catchment area. Overall, it is evident that
temperature forecasts are important for streamflow forecasts in climates
with seasonal snow cover.</p
Enterotoxigenic Escherichia coli and Vibrio cholerae Diarrhea, Bangladesh, 2004
Flooding in Dhaka in July 2004 caused epidemics of diarrhea. Enterotoxigenic Escherichia coli (ETEC) was almost as prevalent as Vibrio cholerae O1 in diarrheal stools. ETEC that produced heat-stable enterotoxin alone was most prevalent, and 78% of strains had colonization factors. Like V. cholerae O1, ETEC can cause epidemic diarrhea
Flexible modelling of spatial variation in agricultural field trials with the R package INLA
The objective of this paper was to fit different established spatial models for analysing agricultural field trials using the open-source R package INLA. Spatial variation is common in field trials, and accounting for it increases the accuracy of estimated genetic effects. However, this is still hindered by the lack of available software implementations. We compare some established spatial models and show possibilities for flexible modelling with respect to field trial design and joint modelling over multiple years and locations. We use a Bayesian framework and for statistical inference the integrated nested Laplace approximations (INLA) implemented in the R package INLA. The spatial models we use are the well-known independent row and column effects, separable first-order autoregressive ( AR1⊗AR1 ) models and a Gaussian random field (Matérn) model that is approximated via the stochastic partial differential equation approach. The Matérn model can accommodate flexible field trial designs and yields interpretable parameters. We test the models in a simulation study imitating a wheat breeding programme with different levels of spatial variation, with and without genome-wide markers and with combining data over two locations, modelling spatial and genetic effects jointly. The results show comparable predictive performance for both the AR1⊗AR1 and the Matérn models. We also present an example of fitting the models to a real wheat breeding data and simulated tree breeding data with the Nelder wheel design to show the flexibility of the Matérn model and the R package INLA
Transforming images: Exploring powerful children
The perception of children as vulnerable, instead of powerful, beings is the opposite of what is found to be the case in the historic evidence. The paper investigates the relationship between ideology and material culture by examining some attitudes towards children found in Scandinavian traditions, which have been connected with archaeological finds. This concerns the area of the Norse Sagas and the comparative studies of religion, folk medicine and folklore in relationship to the tradition of burial alive in the Nordic regions. In relation to children's access to origin of a cosmological order it looks into the Norwegian Odal law of the firstborn and pre-Christian practices concerning the treatment of children
Influence of Additives on Alkaline Etching of Silicon(111)
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