113 research outputs found
Precipitation estimate over the Baltic Sea: Present state of the art
Precipitation is one of the main components in the water balance, and probably the component determined with the greatest uncertainties. In the present paper we focus on precipitation (mainly rain) over the Baltic Sea as a part of the BALTEX project to examine the present state of the art concerning different precipitation estimates over that area. Several methods are used, with the focus on 1) interpolation of available synoptic stations; 2) a mesoscale analysis system including synoptic, automatic, and climate stations, as well as weather radar and an atmospheric model; and 3) measurements performed on ships. The investigated time scales are monthly and yearly and also some long-term considerations are discussed. The comparison shows that the differences between most of the estimates, when averaged over an extended period and a larger area, are in the order of 10-20%, which is in the same range as the correction of the synoptic gauge measurements due to wind and evaporation losses. In all data sets using gauge data it is important to include corrections for high winds. To improve the structure of precipitation over sea more focus is to be put on the use of radar data and combinations of radar data and other data. Interpolation methods that do not consider orographic effects must treat areas with large horizontal precipitation gradients with care. Due to the large variability in precipitation in time and space, it is important to use long time periods for climate estimates of precipitation
Ship measurements are a valuable contribution to precipitation information over sea, especially for seasonal and annual time scales
Collective and broken pair states of 65,67Ga
Excited states of 65Ga and 67Ga nuclei were populated through the 12C(58Ni,αp) and 12C(58Ni,3p) reactions, respectively, and investigated by in-beam γ-ray spectroscopic methods. The NORDBALL array equipped with a charged particle ball and 11 neutron detectors was used to detect the evaporated particles and γ rays. The level schemes of 65,67Ga were constructed on the basis of γγ-coincidence relations up to 8.6 and 10 MeV excitation energy, and Iπ=27/2 and 33/2+ spin and parity, respectively. The structure of 65,67Ga nuclei was described in the interacting boson-fermion plus broken pair model, including quasiproton, quasiproton-two-quasineutron, and three-quasiproton fermion configurations in the boson-fermion basis states. Most of the states were assigned to quasiparticle + phonon and three quasiparticle configurations on the basis of their electromagnetic decay properties
Pronounced Shape Change Induced by Quasiparticle Alignment
Mean lifetimes of high-spin states of 74Kr have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the 40Ca(40Ca,α2p) reaction at a beam energy of 160 MeV with the GASP γ-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations
Beräkning av moln- och dimdepositionen i Sverigemodellen – Resultat för 1997 och 1998 : Estimation of cloud and fog deposition by use of ”Sverigemodellen” – Results for 1997 and 1998
The capture of cloud and fog droplets by vegetation as a possibly important deposition mechanism has been recognised lately after reports of increased forest decline with altitude. We are concerned with interception, impaction and stickiness of polluted cloud water and fog droplets to terrestrial surfaces, including forest canopies. This deposition is mediated by low-level clouds, in which parts of the terrain can be immersed, or by the presence of orographic and radiation fog. In this study the transport of cloud and fog droplets towards terrestrial surfaces is parameterised and the “occult” deposition (mediated by both clouds and fog) is calculated by a new approach, implemented in “Sverigemodellen” (MATCH-Sverige), a 3D Eulerian transport and dispersion model employed for making environmental assessments in Sweden.The model scheme is taking into account the mesoscale analysis (MESAN) of low-cloud coverage and cloud-base height, the visibility analysis, detailed topography information, land use, modelled atmospheric concentrations and the instantaneous deposition parameters for the investigated species (acidifying air pollutants: sulphate and oxidised/reduced nitrogen).The model scheme is validated by comparing with throughfall monitoring of sulphate deposition to coniferous forests at elevated sites in the Swedish mountains. It shows a rather good fit to the measurements, generally within 25%, which is deemed as encouraging. Discrepancies exist though and are subject of discussion. The percentage of occult deposition can be up to 115% of the sum of dry and wet deposition. Therefore we cannot ignore this contribution in the assessments of deposition of acidifying pollutants. The highest fluxes of cloud deposition are assigned to mountainous regions in Northern Sweden, while the highest fog deposition is calculated at a location in Jönköpings County, on the Sydsvenska höglandet
High spin structure of A 90 nuclei interpreted in the framework of the nuclear shell model
Luftföroreningar i Europa under framtida klimat
Ozonmedelhalterna förväntas öka markant (1-2% per decennium, fram till 2050) i centrala och södra Europa, framförallt under sommaren. Maximumhalterna ökar mer än medelhalterna.Nordligaste Europa förväntas få minskande halter, speciellt under vår och höst.Östra Europa får minskande ozonhalter under vintern. I södra Skandinavien ser vi bara småförändringar i ozonhalterna under alla årstider.Halten av marknära sekundära inorganiska partiklar (SIA; Secondary Inorganic Aerosols)ökar kraftigt (3-5% per decennium, fram till 2050) i hela kontinentala Europa under allaårstider förutom vinter. Ökningen är störst runt Medelhavet på sommaren, och halterna är merän 20% högre under 30-års perioden 2021-2050 jämfört med dagens nivåer. 2071-2100beräknas partikelhalterna under sommaren vara minst 50% högre, jämfört med dagenssituation, i stora områden av södra och centrala Europa. Södra Skandinavien torde få enmåttlig ökning av SIA under framförallt under vår och sommar. Nordliga delar avmodellområdet uppvisar minskande SIA halter under alla årstider.Våtdepositionen av svavel- och kväveföreningar minskar mycket kraftigt i södra och västraEuropa under alla årstider, speciellt under den senare delen av simuleringsperioden (2021-2050 till 2071-2100). Stora områden i och kring Medelhavet samt delar av Frankrike, Belgienoch Nederländerna får endast 50%, eller mindre, av dagens deposition under perioden 2071-2100. Norges kust förväntas få en ökad våtdeposition i framtida klimat, speciellt under vårenoch sommaren. Ökningen är större än 50% på flera platser, men det är trots allt en relativtliten yta som påverkas på detta sätt. Minskad (ökad) våtdeposition i modellområdetkompenseras i någon mån av ökad (minskad) torrdeposition. För de flesta områdena kommerdock ändringen i totaldeposition att följa mönstret i våtdepositionen.Resultaten tyder på att flera sekundära luftföroreningar blir mer långlivade. Halterna iatmosfären blir därmed högre, de kommer vidare att kunna spridas över större områden.In order to investigate the effects of climate change on air quality in Europe, we have utilised the regional CTM (chemistry and transport model) MATCH, forced by meteorology representing future climate conditions but keeping the emissions at their current value. The meteorology is from RCA3, the Rossby Center’s regional climate model (covering all Europe on 50 km × 50 km resolution). RCA3 is, in the current study, run under the SRES A2 emission scenario forced with corresponding climate data from ECHAM4/OPYC3 global model on its boundaries. We have applied our CTM on three different 30-year periods representing current, near- and distant future climate (1961-1990, 2021-2050 and 2071-2100, respectively). Detailed description and validation of the climate model and the CTM is given elsewhere. In the present report we report seasonally-averaged changes in near-surface ozone, secondary inorganic aerosols (SIA) and deposition of sulphur and nitrogen containing species in Europe.The seasonal-mean ozone concentrations are expected to increase considerably (1-2% per decade up to 2050) in central and southern Europe, in particular during summer. The daily maximum concentrations are expected to increase even more than the daily mean concentrations. Northernmost Europe is projected to experience lower ozone concentrations under future climate, especially during spring and autumn. The concentration of SIA will increase dramatically in continental Europe during all seasons except winter. The increase is largest around the Mediterranean during summer. The average summertime concentration of SIA will be 20% higher in 2021-2050 and 50% higher in 2071-2100 compared to current levels as a result of changing the meteorology (drier and warmer conditions in central and southern Europe). The increase in atmospheric SIA concentrations is related to the large decrease in wet deposition of sulphur- and nitrogen containing species, which will be the consequence of climate change in large parts of central and southern Europe. Large areas around the Mediterranean, France, Belgium and the Netherlands will receive 50%, or less, of current nitrogen- and sulphur deposition in 2071-2100 compared to present conditions. The Norwegian coast, on the other hand, is expected to receive more sulphur- and nitrogen deposition due to the anticipated increase in precipitation in this area
Jämförelse mellan observationer och fält med griddad klimatologisk information
The report presents results obtained during an intercomparison exercise. At present at SMHI there are a number of systems for anlyzing surface parameters. The aim of this study is to compare some of the analyzed fields (precipitation, temperature and pressure) with observations. Considerable attention is devoted to precipitation. The outcome of the study is: information on the differences between point observations and the spatially averaged information in the fields of precipiation. The discrepancies are explicitly calculated and presented for confidence intervals. insights in the use of analyzed parameters as opposed to observations for a gridbased climatology. way of deterrnining observation outlier
Luftföroreningar i Europa under framtida klimat
Ozonmedelhalterna förväntas öka markant (1-2% per decennium, fram till 2050) i centrala och södra Europa, framförallt under sommaren. Maximumhalterna ökar mer än medelhalterna.Nordligaste Europa förväntas få minskande halter, speciellt under vår och höst.Östra Europa får minskande ozonhalter under vintern. I södra Skandinavien ser vi bara småförändringar i ozonhalterna under alla årstider.Halten av marknära sekundära inorganiska partiklar (SIA; Secondary Inorganic Aerosols)ökar kraftigt (3-5% per decennium, fram till 2050) i hela kontinentala Europa under allaårstider förutom vinter. Ökningen är störst runt Medelhavet på sommaren, och halterna är merän 20% högre under 30-års perioden 2021-2050 jämfört med dagens nivåer. 2071-2100beräknas partikelhalterna under sommaren vara minst 50% högre, jämfört med dagenssituation, i stora områden av södra och centrala Europa. Södra Skandinavien torde få enmåttlig ökning av SIA under framförallt under vår och sommar. Nordliga delar avmodellområdet uppvisar minskande SIA halter under alla årstider.Våtdepositionen av svavel- och kväveföreningar minskar mycket kraftigt i södra och västraEuropa under alla årstider, speciellt under den senare delen av simuleringsperioden (2021-2050 till 2071-2100). Stora områden i och kring Medelhavet samt delar av Frankrike, Belgienoch Nederländerna får endast 50%, eller mindre, av dagens deposition under perioden 2071-2100. Norges kust förväntas få en ökad våtdeposition i framtida klimat, speciellt under vårenoch sommaren. Ökningen är större än 50% på flera platser, men det är trots allt en relativtliten yta som påverkas på detta sätt. Minskad (ökad) våtdeposition i modellområdetkompenseras i någon mån av ökad (minskad) torrdeposition. För de flesta områdena kommerdock ändringen i totaldeposition att följa mönstret i våtdepositionen.Resultaten tyder på att flera sekundära luftföroreningar blir mer långlivade. Halterna iatmosfären blir därmed högre, de kommer vidare att kunna spridas över större områden.In order to investigate the effects of climate change on air quality in Europe, we have utilised the regional CTM (chemistry and transport model) MATCH, forced by meteorology representing future climate conditions but keeping the emissions at their current value. The meteorology is from RCA3, the Rossby Center’s regional climate model (covering all Europe on 50 km × 50 km resolution). RCA3 is, in the current study, run under the SRES A2 emission scenario forced with corresponding climate data from ECHAM4/OPYC3 global model on its boundaries. We have applied our CTM on three different 30-year periods representing current, near- and distant future climate (1961-1990, 2021-2050 and 2071-2100, respectively). Detailed description and validation of the climate model and the CTM is given elsewhere. In the present report we report seasonally-averaged changes in near-surface ozone, secondary inorganic aerosols (SIA) and deposition of sulphur and nitrogen containing species in Europe.The seasonal-mean ozone concentrations are expected to increase considerably (1-2% per decade up to 2050) in central and southern Europe, in particular during summer. The daily maximum concentrations are expected to increase even more than the daily mean concentrations. Northernmost Europe is projected to experience lower ozone concentrations under future climate, especially during spring and autumn. The concentration of SIA will increase dramatically in continental Europe during all seasons except winter. The increase is largest around the Mediterranean during summer. The average summertime concentration of SIA will be 20% higher in 2021-2050 and 50% higher in 2071-2100 compared to current levels as a result of changing the meteorology (drier and warmer conditions in central and southern Europe). The increase in atmospheric SIA concentrations is related to the large decrease in wet deposition of sulphur- and nitrogen containing species, which will be the consequence of climate change in large parts of central and southern Europe. Large areas around the Mediterranean, France, Belgium and the Netherlands will receive 50%, or less, of current nitrogen- and sulphur deposition in 2071-2100 compared to present conditions. The Norwegian coast, on the other hand, is expected to receive more sulphur- and nitrogen deposition due to the anticipated increase in precipitation in this area
- …