ALBERT

Beschreibung: Cyclone Mekunu precipitation has been collected at three stations in southern Oman.

Beschreibung: Hydrogen and oxygen stable isotope analyses of precipitation sampled during Cyclone Mekunu. During Cyclone Mekunu rainfall samples were taken at three different stations in southern Oman. The results are expressed in per mil using the conventional delta-notation relative to Vienna Standard Mean Ocean Water (V-SMOW). More or less independent from the instrument, the 1s reproducibility is commonly better than ± 0.2 per mil (d18O) and ± 0.4 per mil (d2H).

Beschreibung: The Arctic is warming at twice the global average speed, and the warming-induced increases in biogenic volatile organic compounds (BVOCs) emissions from Arctic plants are expected to be drastic. The current global models' estimations of minimal BVOC emissions from the Arctic are based on very few observations and have been challenged increasingly by field data. This study applied a dynamic ecosystem model, LPJ-GUESS, as a platform to investigate short-term and long-term BVOC emission responses to Arctic climate warming. Field observations in a subarctic tundra heath with long-term (13-year) warming treatments were extensively used for parameterizing and evaluating BVOC-related processes (photosynthesis, emission responses to temperature and vegetation composition). We propose an adjusted temperature (T) response curve for Arctic plants with much stronger T sensitivity than the commonly used algorithms for large-scale modelling. The simulated emission responses to 2 °C warming between the adjusted and original T response curves were evaluated against the observed warming responses (WRs) at short-term scales. Moreover, the model responses to warming by 4 and 8 °C were also investigated as a sensitivity test. The model showed reasonable agreement to the observed vegetation CO2 fluxes in the main growing season as well as day-to-day variability of isoprene and monoterpene emissions. The observed relatively high WRs were better captured by the adjusted T response curve than by the common one. During 1999?2012, the modelled annual mean isoprene and monoterpene emissions were 20 and 8 mg C/m**2/yr with an increase by 55 and 57 % for 2 °C summertime warming, respectively. Warming by 4 and 8 °C for the same period further elevated isoprene emission for all years, but the impacts on monoterpene emissions levelled off during the last few years.

Beschreibung: Cyclone Mekunu precipitation has been collected at three stations in southern Oman.