Modelling of ammonia concentrations and deposition of reduced nitrogen in Poland with the FRAME model

Skuteczne zmniejszenie emisji tlenków siarki i azotu w Europie doprowadziło w ostatnich latach do zwiększenia względnego udziału amoniaku w zakwaszeniu i eutrofizacji środowiska przyrodniczego. W pracy zaprezentowano wyniki modelowania rozkładów przestrzennych stężenia oraz depozycji suchej i mokrej amoniaku w Polsce w rozdzielczości 5x5 km. W tym celu zastosowano brytyjski model FRAME, który w ostatnich latach jest przystosowywany do pracy w warunkach polskich. FRAME jest modelem typu Lagrange'a, cechującym się dużą rozdzielczością pionową (33 warstwy) oraz przestrzenną (5x5 km). Walidację modelu w odniesieniu do stężenia i depozycji NHx przeprowadzono na podstawie pomiarów punktowych oraz przez porównanie bilansu depozycji z innymi dostępnymi źródłami danych: EMEP (European Monitoring and Evaluation Program), IOŚ i IMGW. Stwierdzono dużą zgodność wyników uzyskanych za pomocą modelu FRAME z dostępnymi danymi pomiarowymi. Bilans depozycji suchej i mokrej NHx dla Polski, obliczony na podstawie danych uzyskanych za pomocą FRAME, jest zbliżony do podawanego przez EMEP i GIOŚ. Zaprezentowane w pracy wyniki badań wykazują także konieczność poprawy niektórych parametrów w polskiej wersji modelu FRAME. Dotyczy to szczególnie procesu seeder-feeder, którego efektywny wpływ na wielkość mokrej depozycji zmienia się przestrzennie.Over the last ten years the acid and nitrogen deposition have decreased in Poland as a result of decreased emissions. However, the relative contribution of ammonia deposition shows an increasing trend. To support the national monitoring of ammonia concentration and deposition of reduced nitrogen, numerical models have been developed. Here, the gridded emissions and meteorological data for 2002 were applied to estimate the concentration and deposition of NHx for Poland with the FRAME model (Fine Resolution Atmospheric Multi-pollutant Exchange model). FRAME is a Lagrangian model with high spatial (5 x 5 km) and horizontal resolution (33 layers) and was originally developed for the United Kingdom. Because of its high spatial resolution, the model considers the seeder-feeder effect (the washout of polluted hill cloud droplets by raindrops from upper layers), which is largely responsible for enhanced wet deposition over mountainous areas. FRAME results were compared with available data from the monitoring sites and with the EMEP and IMGW/IOŚ estimates of wet and dry deposition. The results show close agreement with measurements (with R2 of 0.71 for wet deposition). Due to the fine spatial resolution of the FRAME model, the spatial distribution of NH3 concentration and NHx deposition shows a complex pattern which can not be noticed in the coarser resolution EMEP model. The FRAME national deposition budget is in close agreement with the EMEP and IMGW estimates. The modelled reduced nitrogen wet deposition is overestimated in the Tatra Mts. This is because of the more continental climate and the seeder-feeder process being less effective, if compared with the UK. This suggests that the efficiency of the seeder-feeder effect, included into the model, should vary spatially

The role of forest and terrain morphology in snow cover development in the Western Sudety - 2003-2004 winter season case study

GIS method was used to describe changes in factors influencing snow cover depth in relation to land cover category (forested/woodless area) and terrain morphology. In the snow cover increase phase, differences in its depth between forest and woodless area weren't visible. During this phase directional screening/exposure indices were responsible for snow cover differentiation. In maximum water equivalent phase the role of terrain roughness as the factor controlling snow depth was clear. On one hand it depends on land cover type, which is especially visible in characteristic of diverse density and height of forest stand, but on the other hand it depends also on terrain morphology. In the snow cover disappearance phase, stand canopy slows the ablation process down and the snow cover in forest is higher than on the open air area. During the whole winter season, significantly smaller impact of absolute altitude, terrain slope and aspect as factors controlling snow cover depth differentiation in the Western Sudety Mountains was observed

Sensitivity of Ground-Level Ozone to NOx Emission During a High Ozone Episode in SW Poland

Sensitivity of ozone formation to NOx and VOC emission is important in terms of implementing control strategies for photochemical pollutants, helping to determine the most effective way to limit O3 concentrations and population exposure to high levels of O3. In this study, the role of NOx emissions on hourly O3 concentrations is examined in order to determine whether NOx is the driver or limiting factor of ozone formation in SW Poland in high-ozone situations. In order to assess that, four scenarios are analyzed: baseline, with no modification of the available emission inventory, a 10, 20 and 30 % decrease in anthropogenic emission of NOx. The simulations were performed for an episode with high O3 concentrations. Both spatial and temporal changes in ozone concentrations for all scenarios have been analyzed. Preliminary results show that reducing NOx emission is associated with higher O3 concentrations, however, further research is needed to assess the role of VOC