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5 results on '"van Velthoven PFJ"'

1. The influence of future non-mitigated road transport emissions on regional ozone exceedences at global scale

Author

Williams, JE, Hodnebrog, Ø, van Velthoven, PFJ, Berntsen, TK, Dessens, O, Gauss, M, Grewe, V, Isaksen, ISA, Olivié, D, Prather, MJ, and Tang, Q

Subjects
Air quality, Road traffic emissions, 3D global chemistry modelling, Future trends, Statistics, Atmospheric Sciences, Environmental Engineering, Meteorology & Atmospheric Sciences
Abstract

Road Transport emissions (RTE) are a significant anthropogenic global NOx source responsible for enhancing the chemical production of tropospheric ozone (O3) in the lower troposphere. Here we analyse a multi-model ensemble which adopts the realistic SRES A1B emission scenario and a "policy-failure" scenario for RTE (A1B_HIGH) for the years 2000, 2025 and 2050. Analysing the regional trends in RTE NOx estimates shows by 2025 that differences of 0.2-0.3TgNyr-1 occur for most of the world regions between the A1B and A1B_HIGH estimates, except for Asia where there is a larger difference of ~1.4TgNyr-1. For 2050 these differences fall to ~0.1TgNyr-1, with shipping emissions becoming as important as RTE. Analysing the seasonality in near-surface O3 from the multi-model ensemble monthly mean values shows a large variability in the projected changes between different regions. For Western Europe and the Eastern US although the peak O3 mixing ratios decrease by ~10% in 2050, there is an associated degradation during wintertime due to less direct titration from nitric oxide. For regions such as Eastern China, although total anthropogenic NOx emissions are reduced from 2025 to 2050, there is no real improvement in peak O3 levels. By normalizing the seasonal ensemble means of near-surface O3 (0-500m) with the recommended European Commission (EC) exposure limit to derive an exceedence ratio (ER), we show that ER values greater than 1.0 occur across a wide area in the Northern Hemisphere for boreal summer using the year 2000 emissions. When adopting the future A1B_HIGH estimates, the Middle East exhibits the worst regional air quality, closely followed by Asia. For these regions the area of exceedence (ER>1.0) for 2025 is ~40% and ~25% of the total area of each region, respectively. Comparing simulations employing the various scenarios shows that unmitigated RTE increases the area of exceedence in the Middle East by ~6% and, for Asia, by ~2% of the total regional areas. For the USA the area of exceedence approximately doubles in 2025 as a result of unmitigated RTE, with the most exceedences occurring in the southern USA. The effects across the various regions implies that unmitigated RTE would have a detrimental effect on regional health for 2025, and potentially offset the benefits introduced by mitigating e.g. international shipping emissions. By 2050 the further mitigation of non-transport emissions results in much cleaner air meaning that mitigation of RTE is not critical for achieving the defined limits in many world regions. © 2014 Elsevier Ltd.

Published
2014

2. Metingen in buitenlucht op het RIVM-terrein te Bilthoven na het Fukushima kernongeval in maart 2011

Author

LSO, mev, Overwater R, Kwakman P, Twenhofel CJW, Knetsch GJ, Scheele MP, van Velthoven PFJ, le Sager P, Kroonenberg FC, Smetsers RCGM, LSO, mev, Overwater R, Kwakman P, Twenhofel CJW, Knetsch GJ, Scheele MP, van Velthoven PFJ, le Sager P, Kroonenberg FC, and Smetsers RCGM

Abstract

RIVM rapport:De in Nederland gemeten radioactiviteit uit Japan ligt duizenden keren lager dan tijdens Tsjernobyl en vormt geen risico voor de Nederlandse bevolking. De berekende stralingsdosis door inhalatie van I-131 over de gehele meetperiode bedraagt minder dan 0,00001 millisievert. De stralingsdosis van Nederlanders is normaal ongeveer 2,5 millisievert per jaar. Bij het kernongeval in Fukushima zijn grote hoeveelheden vluchtige radionucliden in de lucht geloosd. Voorlopige schattingen houden het voor I-131 op ruwweg 10% van wat tijdens Tsjernobyl is vrijgekomen. Deze radionucliden hebben zich in de dagen tot weken daarna verspreid over de atmosfeer op het noordelijk halfrond. Het KNMI geeft aan dat een deel van de uitstoot zich over de Noordpool en een deel zich over de Atlantische oceaan richting Europa heeft verplaatst. Het Laboratorium voor Stralingsonderzoek van het RIVM heeft met meerdere meetopstellingen lucht bemonsterd. Het RIVM heeft een HVS opstelling gebruikt om de dagelijkse variaties in kaart te brengen van de meest relevante radionucliden I-131, Cs-137 en Cs-134. Een bemonsteringsapparaat met een nog hoger debiet, Snow White, is gebruikt om aan stof gebonden radionucliden aan te tonen met nog lagere luchtconcentraties. Apparatuur van de RIVM meetwagens is ingezet om de verschillende fracties van I-131 (stofgebonden, elementair en organisch) te bepalen. In de periode van 23 maart tot 11 april 2011 zijn in Nederlandse buitenlucht sporen van radioactiviteit aangetoond. De hoogste concentraties zijn gevonden voor I-131. Ongeveer 31% daarvan zat in de stofgebonden fractie. De gemiddelde waarde van de stofgebonden fractie over de periode 23 maart - 11 april bedroeg 0,57 milliBq/m3. Als we aannemen dat de stofgebonden fractie over de hele periode constant verondersteld mag worden, leidt dat over de periode 23 maart - 11 april tot een gemiddelde I-131 concentratie (alle fracties samen) van 1,84 milliBq/m3. De gemeten concentraties van Cs-137, Cs-134, Te-129m, Te-129, T

Published
2011

3. AIRFORCE: Aircraft influences and radiative forcing from emissions

Author

LLO, Velders GJM, Beck JP, Bolder M, Bregman B, Kelder H, Lelieveld J, Meijer EW, Scheeren HA, Valks PJM, van Velthoven PFJ, van Weele M, LLO, Velders GJM, Beck JP, Bolder M, Bregman B, Kelder H, Lelieveld J, Meijer EW, Scheeren HA, Valks PJM, van Velthoven PFJ, and van Weele M

Abstract

RIVM rapport:Het mondiale vliegverkeer is de laatste decennia sterk gestegen en groeit naar verwachting in de komende 20 jaar met 5-6% per jaar. De emissies van sporengassen door het vliegverkeer, zoals kooldioxide, stikstofoxiden, koolwaterstoffen, zwaveldioxide, waterdamp en roet kunnen effecten hebben op het milieu en direct en indirect bijdragen aan klimaatveranderingen. Het AIRFORCE project (Aircraft Influences and Radiative Forcing from Emissions) is een project van de drie onderzoeksinstituten (IMAU, KNMI en RIVM) die samen het Nederlands Centrum voor Klimaatonderzoek (CKO) vormen. De doelstellingen van AIRFORCE zijn: onderzoek naar het effect van vliegtuigemissies op de samenstelling van de atmosfeer en naar de directe en indirecte effecten van vliegtuigemissies via de stralings-forcering op het klimaat. De modelresultaten laten zien dat NOx emissies van het huidige vliegverkeer een toename veroorzaken van de NOx- en ozonconcentraties in de hoge troposfeer en lage stratosfeer, hetgeen leidt tot een positieve stralingsforcering. In het project is de dynamica en het chemisch mechanisme van enkele drie dimensionale chemie-transportmodellen (CTMK/TM3 en MOGUNTIA) sterk verbeterd. De resultaten van modelberekeningen zijn vergeleken met beschikbare metingen van de STREAM/AIRFORCE en POLINAT campagnes. In het kader van AIRFORCE is een pluimmodel ontwikkeld dat de chemische omzettingen in de pluim direct achter verkeersvliegtuigen beschrijft., Global air traffic has increased extensively during the last few decades and is expected to increase further over the next 20 years by about 5-6% per year. Emissions of trace gases such as carbon dioxide, nitrogen oxides, hydrocarbons, sulphur oxides, water vapour and soot from aircraft can have environmental effects and contribute directly or indirectly to global warming. The three institutes (IMAU, KNMI en RIVM) that form the Netherlands Centre for Climate Research (CKO) participated in the AIRFORCE project (Aircraft Influences and Radiative Forcing from Emissions). The goals of AIRFORCE are: Research on the effect of aircraft emissions on the composition of the atmosphere and on the direct and indirect effects of aircraft emissions on radiative forcing and climate. The model results indicate that NOx emissions from aircraft cause an increase in the NOx and ozone concentrations in the upper troposphere and lower stratosphere, and a positive radiative forcing. The dynamical and chemical mechanisms of several 3-dimensional chemical-transport models (CTMK/TM3 and MOGUNTIA) have been improved considerable in the project. The results have been compared with available measurements from the STREAM/AIRFORCE and POLINAT campaigns. To account for the chemical conversion and dispersion directly behind an aircraft, an aircraft plume model has been developed in the AIRFORCE project, to translate the aircraft NOx emissions into effective emissions that are used as input in the chemical transport models.

Published
1999

4. Distinctive efficacies of the components contributing to total aviation climate impact

Author

Michael Ponater, Sausen, R, van Velthoven, PFJ, Brüning, C, and Blum, A

Subjects
Aviation Climate Impact, Water Vapour, Efficacy, Contrails, Dynamik der Atmosphäre
Abstract

Separate climate sensitivity simulations were run for all important non-CO2 radiative forcing contributions from aviation (except for contrail cirrus), aiming at the quantification of an individual efficacy parameter for each component. All simulations were performed with the same climate model, E39A. The necessity to scale the original perturbations complicates a straightforward determination of efficacy values, particularly for aviation ozone. The results presented here indicate that a radiative forcing from water vapour increase caused by supersonic aviation would have a similar efficacy than CO2. Ozone changes induced by subsonic aviation and methane changes appear to have an efficacy larger than CO2, but the enhancement is moderate (~1.05). For line-shaped contrails we find an efficacy substantially smaller (~0.6) than CO2 in agreement with previous results. The (small) water vapour increase expected from subsonic aviation shows reduced efficacy (~0.7), too. Similar studies with other climate models are desirable in view of probable model dependency.

5. Intercomparison of in-situ aircraft and satellite aerosol measurements in the stratosphere.

Author

Sandvik OS, Friberg J, Martinsson BG, van Velthoven PFJ, Hermann M, and Zahn A

Abstract

Aerosol composition and optical scattering from particles in the lowermost stratosphere (LMS) have been studied by comparing in-situ aerosol samples from the IAGOS-CARIBIC passenger aircraft with vertical profiles of aerosol backscattering obtained from the CALIOP lidar aboard the CALIPSO satellite. Concentrations of the dominating fractions of the stratospheric aerosol, being sulphur and carbon, have been obtained from post-flight analysis of IAGOS-CARIBIC aerosol samples. This information together with literature data on black carbon concentrations were used to calculate the aerosol backscattering which subsequently is compared with measurements by CALIOP. Vertical optical profiles were taken in an altitude range of several kilometres from and above the northern hemispheric extratropical tropopause for the years 2006-2014. We find that the two vastly different measurement platforms yield different aerosol backscattering, especially close to the tropopause where the influence from tropospheric aerosol is strong. The best agreement is found when the LMS is affected by volcanism, i.e., at elevated aerosol loadings. At background conditions, best agreement is obtained some distance (>2 km) above the tropopause in winter and spring, i.e., at likewise elevated aerosol loadings from subsiding aerosol-rich stratospheric air. This is to our knowledge the first time the CALIPSO lidar measurements have been compared to in-situ long-term aerosol measurements.

Published
2019
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