Marta Martinkova

Evaluation of Relations between Extreme Precipitation and Temperature in Observational Time Series from the Czech Republic

The intensity of precipitation extremes is expected to increase as the climate warms and it may cause floods and increase erosion. From the Clausius-Clapeyron relation (CC) it follows that the maximum moisture content of the atmosphere increases by approximately 7% per degree as temperature rises. However, the increases in observed hourly precipitation extremes of approximately two times the CC relation were described recently. This super CC scaling is attributed to the increased prevalence of convective rainfall and decreased prevalence of stratiform rainfall as temperatures increase. We carried out the disaggregation of precipitation into prevailing stratiform and convective component on the observational data from the Czech Republic for 1966–2006. Then, we analyzed trends in characteristics of disaggregated events and assessed correlation of precipitation intensities with daily mean temperature. The results suggest the increasing trend of convective precipitation in summer. The scaling for total rain events is steeper than for the events with prevailing convective component and for the events with prevailing stratiform component. It is a result of mixing of the two storm types. At higher temperature the events with prevailing convective component prevail and vice versa.

Assessment of runoff nitrogen load reduction measures for agricultural catchments

Abstract Water quality in rural catchments is influenced by many societal and bio-physical factors (e.g. different pollution sources, land use and land cover changes). Good ecological status and surface water quality are currently challenged mainly due to different poorly identified pollution sources. The main objective of this study is to estimate the potential of different measures (land use changes and/or reduction in point sources) and their combinations in decreasing the nitrate-nitrogen load from Jankovský stream catchment. The eco-hydrological model SWIM, which simulates dynamics of nutrients in a catchment was used in the study. The simulations for scenario measures showed that nitrate-nitrogen loads at the outlet can be decreased more by reduction of municipal nitrate-nitrogen sources rather than by agricultural land-use change. Overall, the modeling results demonstrated that the most effective scenario was the combination of total reduction of municipal nitrate-nitrogen sources and agricultural land-use change.