Auroral emission intensities — from validation to prediction

The project aims at producing and publishing a long-term dataset of calibrated intensities of visual auroral emissions at two different latitude regions, based on optical ground-based observations of the aurora. To ensure high-quality intensity values for the analysis, only intensities associated with actual aurora will be taken into account by filtering out observations without aurora. This dataset will become the first-ever local time distribution of auroral intensities at the poleward boundary of the auroral zone (Svalbard), and the first such distribution in nearly 60 years at the main auroral region (mainland Fennoscandia). The project will further explore how well solar wind measurements can predict auroral intensities and also examine any links between intensity and changes in auroral forms. These findings can improve auroral forecasting models, which currently only predict auroral occurrence, not brightness. The study will also assess how well auroral intensity measurements reflect the total energy input to the atmosphere by precipitating particles, and in which conditions these estimates are accurate. Finally, as many images also contain clouds, the project will explore how these cloudy images can help estimate nighttime cloud cover, and how that estimate could be used to improve numerical weather models.

The proposed project aims at producing and publishing a long-term data product of absolute intensity calibrated visual auroral emissions at two different latitude regions by using ground-based optical observations of the aurora. This requires pruning of the auroral image data into Aurora vs. No Aurora, which is methodologically already done for our dataset. This dataset of absolute intensities will be used to construct a local time distribution of visual auroral emission intensities at the latitudes of the main auroral region, for the first time in nearly 60 years, and at the poleward boundary of the auroral region, for the first time ever. The predictability of the local auroral intensities based on the solar wind parameters and the intensity relation to the evolution of auroral forms will be investigated, aiming at improving our understanding of the solar wind effect on the local ionospheric processes. This knowledge of emission intensities can further be implemented in auroral forecast models, which currently only predict the auroral occurrence. As the absolute intensities of auroral emissions have been commonly used as proxies for the precipitating particle and energy fluxes, this project will quantify how well these proxies describe the total energy deposition and in which conditions. Lastly, the proposed project will explore the utility of the auroral image data, which contain clouds, in estimating nighttime cloud cover for the benefit of the local weather forecasting.