Abstract. We present novel measurements of five short-lived brominated source gases (CH2Br2, CHBr3, CH2ClBr, CHCl2Br and CHClBr2). These rather short-lived gases are an important source of bromine to the stratosphere, where they can lead to depletion of ozone. The measurements have been obtained using an in situ gas chromatography and mass spectrometry (GC–MS) system on board the High Altitude and Long Range Research Aircraft (HALO). The instrument is extremely sensitive due to the use of chemical ionization, allowing detection limits in the lower parts per quadrillion (ppq, 10−15) range. Data from three campaigns using HALO are presented, where the upper troposphere and lower stratosphere (UTLS) of the northern hemispheric mid-to-high latitudes were sampled during winter and during late summer to early fall. We show that an observed decrease with altitude in the stratosphere is consistent with the relative lifetimes of the different compounds. Distributions of the five source gases and total organic bromine just below the tropopause show an increase in mixing ratio with latitude, in particular during polar winter. This increase in mixing ratio is explained by increasing lifetimes at higher latitudes during winter. As the mixing ratios at the extratropical tropopause are generally higher than those derived for the tropical tropopause, extratropical troposphere-to-stratosphere transport will result in elevated levels of organic bromine in comparison to air transported over the tropical tropopause. The observations are compared to model estimates using different emission scenarios. A scenario with emissions mainly confined to low latitudes cannot reproduce the observed latitudinal distributions and will tend to overestimate organic bromine input through the tropical tropopause from CH2Br2 and CHBr3. Consequently, the scenario also overestimates the amount of brominated organic gases in the stratosphere. The two scenarios with the highest overall emissions of CH2Br2 tend to overestimate mixing ratios at the tropical tropopause, but they are in much better agreement with extratropical tropopause mixing ratios. This shows that not only total emissions but also latitudinal distributions in the emissions are of importance. While an increase in tropopause mixing ratios with latitude is reproduced with all emission scenarios during winter, the simulated extratropical tropopause mixing ratios are on average lower than the observations during late summer to fall. We show that a good knowledge of the latitudinal distribution of tropopause mixing ratios and of the fractional contributions of tropical and extratropical air is needed to derive stratospheric inorganic bromine in the lowermost stratosphere from observations. In a sensitivity study we find maximum differences of a factor 2 in inorganic bromine in the lowermost stratosphere from source gas injection derived from observations and model outputs. The discrepancies depend on the emission scenarios and the assumed contributions from different source regions. Using better emission scenarios and reasonable assumptions on fractional contribution from the different source regions, the differences in inorganic bromine from source gas injection between model and observations is usually on the order of 1 ppt or less. We conclude that a good representation of the contributions of different source regions is required in models for a robust assessment of the role of short-lived halogen source gases on ozone depletion in the UTLS.

Applying the Terrestrial Systems Modeling Platform, TSMP, this study provides the first simulated long-term (1996–2018), high-resolution (~12.5 km) terrestrial system climatology over Europe, which comprises variables from groundwater across the land surface to the top of the atmosphere (G2A). The data set offers an unprecedented opportunity to test hypotheses related to short- and long-range feedback processes in space and time between the different interacting compartments of the terrestrial system. The physical consistency of simulated states and fluxes in the terrestrial system constitutes the uniqueness of the data set: while most regional climate models (RCMs) have a tendency to simplify the soil moisture and groundwater representation, TSMP explicitly simulates a full 3D soil- and groundwater dynamics, closing the terrestrial water cycle from G2A. As anthopogenic impacts are excluded, the dataset may serve as a near-natural reference for global change simulations including human water use and climate change. The data set is available as netCDF files for the pan-European EURO-CORDEX domain.

Droughts associated with heatwaves are difficult to predict, over the seasonal timescale and beyond, mainly due to the uncertainty of atmospheric forcing (Miralles et al., 2019). However, memory effects, related to the slow dynamics of groundwater-soil water-vegetation systems, mean that the challenge is an initial value problem, which may potentially lead to increased predictive ability over extended periods (Dirmeyer, 2000). The major assumption is that memory effects, including interactions of the groundwater-soil water-vegetation system, under uncertain atmospheric forcing conditions are correctly simulated in the forward model. In recent years, there have been many efforts to establish a reliable seasonal forecasting system, applying various approaches, for example, using statistical tools such as linear stochastic models (e.g.,

reported catastrophic impacts with an increase of cardiovascular and respiratory diseases leading to premature mortality. Climate change adaptation strategies, tailored to each regional context and vulnerability, still require more reliable regional projections of such extreme events (Jacob et al., 2020). Data from regional climate models (RCMs) are a major source to investigate heat waves (

Applying the Terrestrial Systems Modeling Platform, TSMP, this study provides the first simulated long-term (1996-2018), high-resolution (~12.5km) terrestrial system climatology over Europe, which comprises variables from groundwater across the land surface to the top of the atmosphere (G2A). The data set offers an unprecedented opportunity to test hypotheses related to short- and long-range feedback processes in space and time between the different interacting compartments of the terrestrial system. The physical consistency of simulated states and fluxes in the terrestrial system constitutes the uniqueness of the data set: while most regional climate models (RCMs) have a tendency to simplify the soil moisture and groundwater representation, TSMP explicitly simulates the full 3D soil- and groundwater dynamics, closing the terrestrial water cycle from G2A. Anthopogenic impacts are excluded, the dataset may serve therefore as a near-natural reference for global change simulations including human water use and climate change. The data set is available as netCDF files for the pan-European EURO-CORDEX domain.