Basic time invariant boundary parameters, such as topography, land use, soil texture, and derived vegetation and soil properties as defined in the regional climate models Consortium for Small‐scale ...Modeling in Climate Mode (CCLM), and the Weather Research and Forecasting Model (WRF), are investigated in terms of their applicability. The focus is on the comparison of the four available data sets and the investigation of their influences on actual CCLM simulations. Several runs of the CCLM model with National Centers for Environmental Prediction (NCEP) and ERA40 boundary forcings in the Mediterranean Coordinated Regional Climate Downscaling Experiment indicate that the investigated data sets are suitable for the considered region. The variations introduced by the different time invariant boundary data are within the range of the variations resulting from different driving reanalysis data, but lower than the differences obtained in intermodel evaluations, e.g., in Prediction of Regional scenarios and Uncertainties for Defining European Climate Change Risks and Effects (PRUDENCE) and Ensembles‐based predictions of climate changes and their impacts (ENSEMBLES). The variation in the monthly mean values resulting from differences in the land use, topography, and soil data are up to 1.1 K in the area average monthly mean temperature and up to 17% of the observed value of the area average monthly precipitation. The study indicates that CCLM would benefit from further improvements of the time invariant boundary data, especially the soil texture data.
Key Points
The article describes time invariant data of the RCMs WRF and CCLM
Variations in CCLM run are up to 1.1 K in monthly mean temperature
All available data are suitable
In this study, high‐resolution climate change data from the regional climate models COSMO‐CLM, HIRHAM, RegCM, and REMO were evaluated in the Greater Alpine Region (GAR; 4°W–19°W and 43°N–49°N) and ...three additional subareas of 1.5° by 1° in size. Evaluation statistics include mean temperature and precipitation, frequency of days with precipitation over 1 mm and over 15 mm, 90% quantile of the frequency distribution, and maximum number of consecutive dry days. The evaluation for the 1961–1990 period indicates that the models reproduce spatial precipitation patterns and the annual cycle. The mean precipitation domain bias varies between 11% and 40% in winter season and between −14.5% and 11% in summer. Larger errors are found for other statistics and in the various regions. No single best model could be identified comparing modeled precipitation characteristics with observational reference. The study shows that there is still high uncertainty in the expected climate change. Furthermore, future temperature and precipitation changes simulated with different SRES scenarios and calculated by different RCMs overlap. The temperature calculations for the period 2071–2100 related to the period 1961–1990 in the GAR area show an increase in the monthly mean 2m temperature of up to 4.8 K in summer. In the GAR area, a precipitation decrease of up to 29% in summer and precipitation increase of approximately 20% in the winter season is simulated. Summer and autumn temperatures are expected to increase more than winter and spring temperatures. Detailed analysis reveals that the different regional climate model runs based on different regional models, different driving global models and different emission scenarios show similar trends, but differ in the magnitude of the expected climate change signal. All models seem to agree on the increased frequency of high‐precipitation events in the winter season.
For the estimation of future climate conditions in the Jordan River region, the National Center for Atmospheric Research–Penn State University meteorology model in the versions 3.5 and 3.7 driven ...with boundary data from the Max‐Planck‐Institute for Meteorology and Hadley Centre global circulation models and the Special Report on Emission Scenarios A1B emission scenario has been used. The spatial resolution of the nested dynamic downscaling approach was 18.6 km, and the transient runs were performed for the period 1960–2099. The investigated statistics include mean precipitation, frequency and intensity of wet days and strong precipitation events, as well as mean temperature and heat wave duration index. The results show that the models satisfactorily reproduce the mean temperature and precipitation patterns. The comparison with the observational reference for the period 1961–1990 reveals a bias in the annual mean precipitation ranging from −20% to +17%, with an ensemble mean of −3%. The models show limitations in reproducing the precipitation seasonality. All models underestimate the wet day frequency and show differences in the strong precipitation events. The simulations of the future climate signal indicate an ensemble mean increase of the annual mean temperature of approximately 2.1 K in the period 2031–2060 and 3.7 K for the period 2070–2099 related to the 1961–1991 mean. In the same periods, the annual mean precipitation is simulated to decrease by approximately −11.5% and −20%, respectively, which means a reduction of expected water availability in the Jordan River region. All models show an increase of the heat wave duration index. A significant elevation dependence is present in the simulated future climate signal on both temperature and precipitation. The simulations show an increased coefficient of variation in annual precipitation, indicating that larger interannual precipitation variability can be expected in the future.
Key Points
Significant reduction of expected water availability in the Jordan River region
Significant elevation signal present in the simulated future climate
Increased coefficient of variation in simulated future annual precipitation
Core Ideas
Pre‐alpine areas face more intense warming and extreme hydrological events than the global average.
Climate and land management change have far‐reaching impacts on ecosystem functions and ...services.
We have improved knowledge of water, energy, and matter exchange by long‐term observations and modeling.
Global change has triggered several transformations, such as alterations in climate, land productivity, water resources, and atmospheric chemistry, with far reaching impacts on ecosystem functions and services. Finding solutions to climate and land cover change‐driven impacts on our terrestrial environment is one of the most important scientific challenges of the 21st century, with far‐reaching interlinkages to the socio‐economy. The setup of the German Terrestrial Environmental Observatories (TERENO) Pre‐Alpine Observatory was motivated by the fact that mountain areas, such as the pre‐alpine region in southern Germany, have been exposed to more intense warming compared with the global average trend and to higher frequencies of extreme hydrological events, such as droughts and intense rainfall. Scientific research questions in the TERENO Pre‐Alpine Observatory focus on improved process understanding and closing of combined energy, water, C, and N cycles at site to regional scales. The main long‐term objectives of the TERENO Pre‐Alpine Observatory include the characterization and quantification of climate change and land cover–management effects on terrestrial hydrology and biogeochemical processes at site and regional scales by joint measuring and modeling approaches. Here we present a detailed climatic and biogeophysical characterization of the TERENO Pre‐Alpine Observatory and a summary of novel scientific findings from observations and projects. Finally, we reflect on future directions of climate impact research in this particularly vulnerable region of Germany.
The impact of biogenic volatile organic compound (BVOC) emissions on European ozone distributions has not yet been evaluated in a comprehensive way. Using the CHIMERE chemistry-transport model the ...variability of surface ozone levels from April to September for 4 years (1997, 2000, 2001, 2003) resulting from biogenic emissions is investigated. It is shown that BVOC emissions increased on average summer daily ozone maxima over Europe by 2.5
ppbv (5%). The impact is most significant in Portugal (up to 15
ppbv) and in the Mediterranean region (about 5
ppbv), being smaller in the northern part of Europe (1.3
ppbv north of 47.5°N). The average impact is rather similar for the three summers (1997, 2000, 2001), but is much larger during the extraordinarily hot summer of 2003. Here, the biogenic contribution to surface ozone doubles compared to other years at some locations. Interaction with anthropogenic NO
x
emissions is found to be a key process for ozone production of biogenic precursors. Comparing the impact of the state-of-the-art BVOC emission inventory compiled within the NatAir project and an earlier, widely used BVOC inventory derived from Simpson et al. 1999. Inventorying emissions from nature in Europe. Journal of Geophysical Research 104(D7), 8113–8152 on surface ozone shows that ozone produced from biogenic precursors is less in central and northern Europe but in certain southern areas much higher e.g. Iberian Peninsula and the Mediterranean Sea. The uncertainty in the regionally averaged impact of BVOC on ozone build-up in Europe is estimated to be ±50%.
Understanding changing trends and frequency of extreme rainfall and temperature events is extremely important for optimal planning in many sectors, including agriculture, water resource management, ...health, and even economics. For people living in the Jordan River region of the Middle East such changes can have immediate devastating impacts as water resources are already scarce and overexploited and summer temperatures in the desert regions can reach 45°C or higher. Understanding shifts in frequency and intensity of extreme events can provide crucial information for planning and adaptation. In this paper we present results from regional climate model simulations with RegCM3 and MM5 centered on the eastern Mediterranean region. Our analysis focuses on changes in extreme temperature and rainfall events. We show that maximum daily summer temperature is expected to increase by between 2.5°C and 3°C, with an increase in warm spell length. Precipitation extremes are expected to increase with longer dry spells, shorter wet spells, and increases in heavy rainfall. Model agreement for the control period 1961–1990 is higher in the southern region than in the north, perhaps because of the complex topography, suggesting that even small differences in spatial scale play an important role. In addition, we notice that the chosen global model plays an important role in determining future temperature trends, while the choice of regional climate model is critical for understanding how precipitation is expected to evolve.
Key Points
The simulations show a future temperature increase in range of 2.5‐3 degrees
Dry spells are simulated to increase in the future
Increase in heavy rainfall despite the decrease in annual mean precipitation
Forest soils are a significant source for the primary and secondary greenhouse gases N2O and NO. However, current estimates are still uncertain due to the still limited number of field measurements ...and the herein observed pronounced variability of N trace gas fluxes in space and time, which are due to the variation of environmental factors such as soil and vegetation properties or meteorological conditions. To overcome these problems we further developed a process-oriented model, the PnET-N-DNDC model, which simulates the N trace gas exchange on the basis of the processes involved in production, consumption and emission of N trace gases. This model was validated against field observations of N trace gas fluxes from 19 sites obtained within the EU project NOFRETETE, and shown to perform well for N2O (r2=0.68, slope=0.76) and NO (r2=0.78, slope=0.73). For the calculation of a European-wide emission inventory we linked the model to a detailed, regionally and temporally resolved database, comprising climatic properties (daily resolution), and soil parameters, and information on forest areas and types for the years 1990, 1995 and 2000. Our calculations show that N trace gas fluxes from forest soils may vary substantial from year to year and that distinct regional patterns can be observed. Our central estimate of NO emissions from forest soils in the EU amounts to 98.4, 84.9 and 99.2 kt N yr?1, using meteorology from 1990, 1995 and year 2000, respectively. This is <1.0% of pyrogenic NOx emissions. For N2O emissions the central estimates were 86.8, 77.6 and 81.6 kt N yr?1, respectively, which is approx. 14.5% of the source strength coming from agricultural soils. An extensive sensitivity analysis was conducted which showed a range in emissions from 44.4 to 254.0 kt N yr?1 for NO and 50.7 to 96.9 kt N yr?1 for N2O, for year 2000 meteorology.
The results show that process-oriented models coupled to a GIS are useful tools for the calculation of regional, national, or global inventories of biogenic N trace gas emissions from soils. This work represents the most comprehensive effort to date to simulate NO and N2O emissions from European forest soils.
An uncertainty assessment of a volatile organic compounds (VOCs) emission inventory using a Monte Carlo study according to the “Good Practice Guidance and Uncertainty Management in National ...Greenhouse Gas Inventories” has been performed. For the episode of 1–10 July 2000 hourly biogenic VOC (BVOC) emissions from forests in Poland were calculated in 10 km × 10 km resolution with a semiempirical BVOC model (seBVOC). Driving parameters of the model were land cover, temperature, light intensity, foliar biomass, leaf area index (LAI), and plant‐specific emission factors. The hourly meteorology input has been modeled with the nonhydrostatic Multiscale Climate Chemistry Model (MCCM). For each of the driving parameters, probability distribution functions (PDFs) based on the normal and log‐normal distributions have been identified. Repeated runs of the seBVOC model in the Monte Carlo study with random figures drawn from the probability distribution functions yield the error distribution and the uncertainties. The results show an uncertainty in isoprene emission of the entire modeled period and modeling domain in the range from −71% to 73%, in monoterpene emissions in the range of −57% to 140%, and in other VOC (OVOC) emissions in the range of −55% to 57%. Uncertainties in daily estimates for the domain were higher ranging between −84% and 98% for isoprene, −63% and 147% for monoterpenes, and 63% and 72% for other VOCs. Largest uncertainty results from errors of the emission factors followed by errors in temperature and foliar biomass. These uncertainties cover only a subset of possible variables and are less than the total uncertainty.
An inventory describing the fluxes of the volatile organic compound (VOC), isoprene, and the class of VOCs, the monoterpenes, from the biosphere to the atmosphere has been constructed for Great ...Britain (GB). The controlling parameters were emission potentials from individual plant species, plant species distribution, biomass distribution, temperature, and light intensity. Species distribution and cover data from a national survey of vegetation in 1990 were used. A database of monthly biomass factors was compiled and a qualitative database of VOC emission potentials from vegetation species was updated to a quantitative form. This was used in conjunction with a taxonomic methodology to assign isoprene and monoterpene emission potentials to each plant species extant in GB. Hourly meteorological data for 1998 were calculated using a three‐dimensional nonhydrostatic meteorological mesoscale model (MM5) and these were used to predict the isoprene and monoterpene fluxes in GB in 1998 on a spatial scale of 12 × 12 km and with an hourly temporal resolution. Estimates of annual biogenic isoprene and monoterpene fluxes were 8 and 83 kt, respectively, for the model year. Picea sitchensis (Sitka spruce) is the dominant emitting species in GB, emitting approximately 40% of the annual isoprene and monoterpene fluxes. The dominant emitting regions in GB are coniferous forests in Scotland (isoprene and monoterpenes) and a Populus spp. (poplar) rich area in eastern England (isoprene). Overall uncertainty in the estimates is a maximum of a factor of 4. A sensitivity analysis of the model was used to study the impact of changes in vegetation cover and climate on VOC emission.
Biogenic VOC emission estimates from the earth's surface are crucial input parameters in air quality models. Knowledge accumulated in the last years about BVOC source distributions and chemical ...compound species emission profiles in Europe as well as the demand of air quality modellers for a finer resolution in space and time of BVOC estimates have led to the set-up of new emission modelling systems. An updated fast BVOC emission modelling platform explicitly considering the seasonality of emission potentials and leaf temperature gradients in forest canopies by the semi-empirical emission module (seBVOC) will be proposed and used for estimating hourly values of chemical compound-specific emissions in Europe (33–68° north; 10° west to 40° east) in the years 1997, 2000, 2001, and 2003. Spatial resolution will be 10
km by 10
km. The database used contains latest land and forest distributions, updated foliar biomass densities, leaf area indices (LAI), and plant as well as chemical compound-specific emission potentials, if available. Meteorological input parameters for the respective years will be generated using the non-hydrostatic meteorological model MM5. Highest BVOC emissions occur in daytime hours around noon from the end of May to mid-August in the Mediterranean area and from the mid of June to the end of July in the boreal forests. Comparison of 3 BVOC model approaches will reveal that for July 2003, the European isoprene and monoterpene totals range from 1124
Gg to 1446
Gg and from 338
Gg to 1112
Gg, respectively. Small-scale deviations may be as high as ±0.6
Mg
km
−2 for July 2003, reflecting the current uncertainty range for BVOC estimates. Key sources of errors in inventories are still insufficiently detailed land use data for some areas and lacking chemically speciated plant-specific emission potentials in particular in boreal, south-eastern, and northern African landscapes. The hourly emissions of isoprene, speciated terpenes, and oxyVOC have been made available by the NatAir database.
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