Found 9764 publications. Showing page 55 of 391:
2010
2010
Availability and quality of EMEPs POP and heavy metal measurements. Powerpoint presentation. NILU F
2005
2015
2013
2013
2022
Background concentrations in Norway - Temporal averaging and uncertainty assessment. NILU OR
A system for providing approximate spatial and temporal estimates of the surface background concentrations of PM10 , PM2.5, NO2 , and O3 for a typical year in Norway has been established at NILU in recent years. In 2013, the system was further improved and expanded by carrying out two main tasks: Firstly the spatial component of the system was extended from previously a single year to a 3-year average, thus decreasing the impact of inter-annual variability. Secondly, a preliminary validation of the background estimates was carried out and an approximate uncertainty was calculated for four species in the dataset and is now communicated to the user on the project website. The validation results indicate that overall the average estimated concentrations follow the average observed concentration fairly well. This is particularly true for PM10 and PM2.5. The averaged estimates for O3 and NO2 also follow the averaged observations relatively closely, although NO2 is clearly underestimated at all four validation stations. In terms of quantitative uncertainty estimates for the hourly estimates at the level of individual species, O3 is the parameter which was found to have the lowest uncertainty of all four species. While the median absolute uncertainty for hourly O3 estimates was found to be 18.7 ¿g m-3, the median relative uncertainty was only 33.8 %. Both PM10 and PM2.5 had significantly higher uncertainties, with a median relative uncertainty for the hourly estimates of 90 % and 88 %, respectively. Finally, the hourly estimates for NO2 also showed quite high relative uncertainties with a value of 73 %.
2013
Background concentrations in Norway: Towards automated annual updates. NILU OR
A semi-automated technique was developed for performing annual updates of the dataset on background concentrations in Norway which was produced in previous years. The code is written in the Matlab programming language and large parts of the code base are included in the Appendix of this report.
The spatial component of the system was updated to include data from 2009 through 2011. Acquiring and preparing the input data for the spatial component still requires a relatively small amount of manual effort, however the majority of the remaining process has been automated to the largest extent possible, such that only the derivation of the emivariograms for the residual kriging step requires very brief interaction by an expert user.
The temporal component has been updated to version 8 of the European air quality database (AirBase), now including several additional years up to and including 2013. Entirely new anomaly matrices have been calculated from the updated data for all background stations in Norway.
Assuming that the availability and the format of the required input data remains unchanged, future annual updates of the system can be carried out within a very short time frame on the order of around 1-2 days.
2014
2010
2005
2025
2022
2022
Balloon and surface UV radiation measurements with the NILU-CUBE instrument. Poster presentation. NILU F
2003