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Shilong Piao - One of the best experts on this subject based on the ideXlab platform.
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Wet Deposition of atmospheric inorganic nitrogen at five remote sites in the tibetan plateau
Atmospheric Chemistry and Physics, 2015Co-Authors: Yuesi Wang, Shilong PiaoAbstract:Abstract. Since the mid-20th century, nitrogen (N) Deposition has shown an increasing trend in the Tibetan Plateau (TP), where alpine ecosystems are sensitive to elevated N Deposition. However, the quantitative characterization of N Deposition in the TP remains unclear, due in most part to the lack of in situ measurement. Using the Tibetan Observation and Research Platform network, we conducted short-term in situ measurements of major ions (NO3−, Cl−, SO42−, NH4+, Na+, K+, Ca2+, and Mg2+) Wet Deposition at five remote sites in the TP during 2011–2013. At Southeast Tibet Station, Nam Co Station, Qomolangma Station, Ngari Station, and Muztagh Ata Station, the NH4+–N Wet Deposition was 0.63, 0.68, 0.92, 0.36, and 1.25 kg N ha−1 yr−1, respectively; the NO3−–N Wet Deposition was 0.28, 0.24, 0.03, 0.08, and 0.30 kg N ha−1 yr−1, respectively; and the inorganic N Wet Deposition was 0.91, 0.92, 0.94, 0.44, and 1.55 kg N ha−1 yr−1, respectively. The inorganic N Wet Deposition mainly occurred in the form of NH4+–N during summer at all sites. Results of enrichment factor analysis and principal component analysis demonstrated that both NH4+–N and NO3−–N Wet Deposition in the TP were mainly influenced by anthropogenic activities. Backward trajectory analysis showed that the inorganic N Deposition at Muztagh Ata Station was mainly transported from central Asia and the Middle East through westerlies. At Southeast Tibet Station, Nam Co Station, Qomolangma Station, and Ngari Station, the inorganic N Deposition was mainly contributed by anthropogenic sources in south Asia, and was mainly transported by the Indian monsoon. Combining site-scale in situ measurements of inorganic N Wet Deposition in this and previous studies, the average Wet Deposition of atmospheric NH4+–N, NO3−–N, and inorganic N in the TP was estimated to be 1.06, 0.51, and 1.58 kg N ha−1 yr−1, respectively. The average NH4+–N : NO3−–N ratio in precipitation in the TP was approximately 2 : 1. Results from the present study suggest that earlier estimations based on chemical transport model simulations and/or limited field measurements likely overestimated substantially the regional inorganic N Wet Deposition in the TP. To clarify the total N Deposition in the TP more clearly, it is essential to conduct long-term monitoring of both Wet and dry Deposition of atmospheric N in various climate zones in the TP in the future.
Sabine Banzhaf - One of the best experts on this subject based on the ideXlab platform.
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implementation and evaluation of ph dependent cloud chemistry and Wet Deposition in the chemical transport model rem calgrid
Atmospheric Environment, 2012Co-Authors: Sabine Banzhaf, A. Kerschbaumer, Martijn Schaap, Eric Van Der Swaluw, R. Stern, E. Reimer, Peter BuiltjesAbstract:The Chemistry Transport Model REM-Calgrid (RCG) has been improved by implementing an enhanced description of aqueous-phase chemistry and Wet Deposition processes including droplet pH. A sensitivity study on cloud and rain droplet pH has been performed to investigate its impact on model sulphate production and gas Wet scavenging. Air concentrations and Wet Deposition fluxes of the model sensitivity runs have been analysed and compared to observations. It was found that droplet pH variation within atmospheric ranges affects modelled air concentrations and Wet Deposition fluxes significantly. Applying a droplet pH of 5.5 for July 2005, mean sulphate air concentrations increased by up to 10% compared to using a droplet pH of 5 while SO 2 domain Wet Deposition sum increased by 110%. Moreover, model results using modelled droplet pH for January and July 2005 have been compared to model results applying a constant pH of 5 and to observations. The comparison to observations has shown that using a variable droplet pH improves the model performance concerning air concentrations and Wet Deposition fluxes of the investigated sulphur and nitrogen compounds. For SO x Wet Deposition fluxes the Root Mean Square Error (RMSE) decreased by 16% for July 2005 when using a variable droplet pH instead of a constant pH of 5. Concerning sulphate and SO 2 air concentrations the RMSE was reduced by 8% and 16% for July 2005, respectively. The results have revealed that applying a variable droplet pH is preferable to using a constant pH leading to better consistency concerning air concentrations and Wet Deposition fluxes. © 2011 Elsevier Ltd.
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Wet Deposition: Model Development and Evaluation
Air Pollution Modeling and its Application XXI, 2011Co-Authors: Sabine Banzhaf, Peter Builtjes, A. Kerschbaumer, Martijn Schaap, Eric Van Der Swaluw, R. Stern, E. ReimerAbstract:The Chemistry Transport Model REM-Calgrid (RCG) has been improved by implementing a more detailed description of aqueous-phase chemistry and Wet Deposition processes including droplet pH. A sensitivity study on cloud and rain droplet pH has been performed to investigate its impact on model sulphate production and gas Wet scavenging. Air concentrations and Wet Deposition fluxes of model runs applying differing droplet pH have been analysed and compared to observations. It was found that droplet pH variation within atmospheric ranges affects modelled air concentrations and Wet Deposition fluxes significantly.
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Measuring and Modeling Wet Deposition Fluxes in the Netherlands and Europe
Air Pollution Modeling and its Application XXI, 2011Co-Authors: Eric Van Der Swaluw, Sabine Banzhaf, Martijn Schaap, Ferd Sauter, Astrid MandersAbstract:The Dutch National Precipitation Chemistry Monitoring Network measures the Wet Deposition fluxes of acidifying and eutrophying compounds and heavy metals over the Netherlands since 1978. Recent measurements of sulfate, ammonium and nitrate of this precipitation network are used to validate the outcome of the new Wet Deposition module implemented into the regional air quality model LOTOS-EUROS. The old Wet Deposition module only included below-cloud scavenging, whereas the new Wet Deposition module takes into account below-cloud and in-cloud scavenging. Both processes are implemented such that the effect of the saturation of rain droplets on the scavenging efficiency is included. A simple parameterization, based on the liquid water content data from ECMWF, is used to distinguish between regions in which respectively below-cloud or in-cloud scavenging occurs. In general, it is found that the combination of below-cloud and in-cloud scavenging increases the net scavenging process in the LOTOS-EUROS model simulations; hence the Wet Deposition fluxes are increased. These increased Wet Deposition fluxes in the model simulations are evaluated at the sites of the precipitation network in the Netherlands and show a better agreement as compared to results of simulations performed with the old Wet Deposition module. Finally the Wet Deposition fluxes are also evaluated at the sites of the European EMEP monitoring stations: a similar improvement is found again between the measurements and model results.
Eric Van Der Swaluw - One of the best experts on this subject based on the ideXlab platform.
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implementation and evaluation of ph dependent cloud chemistry and Wet Deposition in the chemical transport model rem calgrid
Atmospheric Environment, 2012Co-Authors: Sabine Banzhaf, A. Kerschbaumer, Martijn Schaap, Eric Van Der Swaluw, R. Stern, E. Reimer, Peter BuiltjesAbstract:The Chemistry Transport Model REM-Calgrid (RCG) has been improved by implementing an enhanced description of aqueous-phase chemistry and Wet Deposition processes including droplet pH. A sensitivity study on cloud and rain droplet pH has been performed to investigate its impact on model sulphate production and gas Wet scavenging. Air concentrations and Wet Deposition fluxes of the model sensitivity runs have been analysed and compared to observations. It was found that droplet pH variation within atmospheric ranges affects modelled air concentrations and Wet Deposition fluxes significantly. Applying a droplet pH of 5.5 for July 2005, mean sulphate air concentrations increased by up to 10% compared to using a droplet pH of 5 while SO 2 domain Wet Deposition sum increased by 110%. Moreover, model results using modelled droplet pH for January and July 2005 have been compared to model results applying a constant pH of 5 and to observations. The comparison to observations has shown that using a variable droplet pH improves the model performance concerning air concentrations and Wet Deposition fluxes of the investigated sulphur and nitrogen compounds. For SO x Wet Deposition fluxes the Root Mean Square Error (RMSE) decreased by 16% for July 2005 when using a variable droplet pH instead of a constant pH of 5. Concerning sulphate and SO 2 air concentrations the RMSE was reduced by 8% and 16% for July 2005, respectively. The results have revealed that applying a variable droplet pH is preferable to using a constant pH leading to better consistency concerning air concentrations and Wet Deposition fluxes. © 2011 Elsevier Ltd.
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Wet Deposition: Model Development and Evaluation
Air Pollution Modeling and its Application XXI, 2011Co-Authors: Sabine Banzhaf, Peter Builtjes, A. Kerschbaumer, Martijn Schaap, Eric Van Der Swaluw, R. Stern, E. ReimerAbstract:The Chemistry Transport Model REM-Calgrid (RCG) has been improved by implementing a more detailed description of aqueous-phase chemistry and Wet Deposition processes including droplet pH. A sensitivity study on cloud and rain droplet pH has been performed to investigate its impact on model sulphate production and gas Wet scavenging. Air concentrations and Wet Deposition fluxes of model runs applying differing droplet pH have been analysed and compared to observations. It was found that droplet pH variation within atmospheric ranges affects modelled air concentrations and Wet Deposition fluxes significantly.
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Measuring and Modeling Wet Deposition Fluxes in the Netherlands and Europe
Air Pollution Modeling and its Application XXI, 2011Co-Authors: Eric Van Der Swaluw, Sabine Banzhaf, Martijn Schaap, Ferd Sauter, Astrid MandersAbstract:The Dutch National Precipitation Chemistry Monitoring Network measures the Wet Deposition fluxes of acidifying and eutrophying compounds and heavy metals over the Netherlands since 1978. Recent measurements of sulfate, ammonium and nitrate of this precipitation network are used to validate the outcome of the new Wet Deposition module implemented into the regional air quality model LOTOS-EUROS. The old Wet Deposition module only included below-cloud scavenging, whereas the new Wet Deposition module takes into account below-cloud and in-cloud scavenging. Both processes are implemented such that the effect of the saturation of rain droplets on the scavenging efficiency is included. A simple parameterization, based on the liquid water content data from ECMWF, is used to distinguish between regions in which respectively below-cloud or in-cloud scavenging occurs. In general, it is found that the combination of below-cloud and in-cloud scavenging increases the net scavenging process in the LOTOS-EUROS model simulations; hence the Wet Deposition fluxes are increased. These increased Wet Deposition fluxes in the model simulations are evaluated at the sites of the precipitation network in the Netherlands and show a better agreement as compared to results of simulations performed with the old Wet Deposition module. Finally the Wet Deposition fluxes are also evaluated at the sites of the European EMEP monitoring stations: a similar improvement is found again between the measurements and model results.
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Wet Deposition of ammonium, nitrate and sulfate in the Netherlands over the period 1992–2008
Atmospheric Environment, 2011Co-Authors: Eric Van Der Swaluw, Willem A.h. Asman, Hans A. Van Jaarsveld, R. HoogerbruggeAbstract:Abstract We present measurements of Wet Deposition of ammonium, nitrate and sulfate in the Netherlands over the period 1992–2008. These data series are obtained from the Dutch National Precipitation Chemistry Monitoring Network which consists of 11 monitoring stations which are homogeneously spread over the Netherlands. These long-term measurements allow for a trend analysis over this period, which are to a large extent not influenced by the year to year variations in meteorological circumstances. It is shown that the downward trend of ammonium, nitrate and sulfate Wet Deposition over the period 1992–2008 are statistically significant: the Wet Deposition in the Netherlands decreased in the period 1992–2008 by 37% for ammonium, 28% for nitrate and 59% for sulfate. A comparison between the measurements and emissions are made in order to check whether the emissions show similar downward trends. Subsequently a comparison is made between measured and calculated Wet Deposition fluxes. These calculation results were performed with the Operational Priority Substances (OPS-model). The trends in both the emissions and the calculated Wet Deposition fluxes show good agreement for all three measured components. It is therefore concluded that the downward trends of the Wet Deposition fluxes are a direct effect of the decrease of emissions. Finally, it is shown that the relative downward trend of the Wet Deposition fluxes of sulfate in the Netherlands shows a large-scale structure with a gradient running from east to west. A similar pattern is seen in the simulations performed with the OPS-model.
M A Sutton - One of the best experts on this subject based on the ideXlab platform.
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modelling the Wet Deposition of reduced nitrogen over the british isles using a lagrangian multi layer atmospheric transport model
Quarterly Journal of the Royal Meteorological Society, 2005Co-Authors: N Fournier, Anthony J. Dore, K J Weston, M A SuttonAbstract:Wet Deposition of reduced nitrogen is estimated for the United Kingdom using a Lagrangian long-term, long-range atmospheric transport model. Such long-range transport models are used to develop emission-control strategies to combat environmental acidification in the sensitive regions of the United Kingdom and Europe. These models currently consider the Wet Deposition as a loss term using scavenging rates and a simple seeder–feeder effect. The seeder–feeder effect is assumed to be the main process producing orographic precipitation since the majority of British Isles annual rainfall falls in frontal events. This paper focuses on the analysis of different parametrizations of the removal process by Wet Deposition. It is shown that the seeder–feeder effect is very dependent on flow direction. Therefore, a model of directional orographic enhancement of precipitation is developed to simulate this effect. A revised formulation of the Wet Deposition parametrization is suggested, incorporating the directional orographic precipitation produced with this model. This new formulation also takes into account the larger concentrations of ions dissolved in rain water measured in mountainous areas. Moreover, a new representation of the Wet Deposition process is developed by considering explicitly the mixing layer's depth calculated in the model. The results from the atmospheric model, with these revised parametrizations of the Wet Deposition, are then compared with measured Wet Deposition of reduced nitrogen. Firstly, with the new directional orographic rainfall, the modelled United Kingdom reduced nitrogen Wet Deposition budget is still underestimated but an increased correlation with measurements is obtained. Secondly, the inclusion of the calculated mixing layer's depth leads to a considerable improvement in the modelled reduced nitrogen Wet Deposition budget compared with measurements. Copyright © 2005 Royal Meteorological Society.
Martijn Schaap - One of the best experts on this subject based on the ideXlab platform.
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implementation and evaluation of ph dependent cloud chemistry and Wet Deposition in the chemical transport model rem calgrid
Atmospheric Environment, 2012Co-Authors: Sabine Banzhaf, A. Kerschbaumer, Martijn Schaap, Eric Van Der Swaluw, R. Stern, E. Reimer, Peter BuiltjesAbstract:The Chemistry Transport Model REM-Calgrid (RCG) has been improved by implementing an enhanced description of aqueous-phase chemistry and Wet Deposition processes including droplet pH. A sensitivity study on cloud and rain droplet pH has been performed to investigate its impact on model sulphate production and gas Wet scavenging. Air concentrations and Wet Deposition fluxes of the model sensitivity runs have been analysed and compared to observations. It was found that droplet pH variation within atmospheric ranges affects modelled air concentrations and Wet Deposition fluxes significantly. Applying a droplet pH of 5.5 for July 2005, mean sulphate air concentrations increased by up to 10% compared to using a droplet pH of 5 while SO 2 domain Wet Deposition sum increased by 110%. Moreover, model results using modelled droplet pH for January and July 2005 have been compared to model results applying a constant pH of 5 and to observations. The comparison to observations has shown that using a variable droplet pH improves the model performance concerning air concentrations and Wet Deposition fluxes of the investigated sulphur and nitrogen compounds. For SO x Wet Deposition fluxes the Root Mean Square Error (RMSE) decreased by 16% for July 2005 when using a variable droplet pH instead of a constant pH of 5. Concerning sulphate and SO 2 air concentrations the RMSE was reduced by 8% and 16% for July 2005, respectively. The results have revealed that applying a variable droplet pH is preferable to using a constant pH leading to better consistency concerning air concentrations and Wet Deposition fluxes. © 2011 Elsevier Ltd.
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Wet Deposition: Model Development and Evaluation
Air Pollution Modeling and its Application XXI, 2011Co-Authors: Sabine Banzhaf, Peter Builtjes, A. Kerschbaumer, Martijn Schaap, Eric Van Der Swaluw, R. Stern, E. ReimerAbstract:The Chemistry Transport Model REM-Calgrid (RCG) has been improved by implementing a more detailed description of aqueous-phase chemistry and Wet Deposition processes including droplet pH. A sensitivity study on cloud and rain droplet pH has been performed to investigate its impact on model sulphate production and gas Wet scavenging. Air concentrations and Wet Deposition fluxes of model runs applying differing droplet pH have been analysed and compared to observations. It was found that droplet pH variation within atmospheric ranges affects modelled air concentrations and Wet Deposition fluxes significantly.
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Measuring and Modeling Wet Deposition Fluxes in the Netherlands and Europe
Air Pollution Modeling and its Application XXI, 2011Co-Authors: Eric Van Der Swaluw, Sabine Banzhaf, Martijn Schaap, Ferd Sauter, Astrid MandersAbstract:The Dutch National Precipitation Chemistry Monitoring Network measures the Wet Deposition fluxes of acidifying and eutrophying compounds and heavy metals over the Netherlands since 1978. Recent measurements of sulfate, ammonium and nitrate of this precipitation network are used to validate the outcome of the new Wet Deposition module implemented into the regional air quality model LOTOS-EUROS. The old Wet Deposition module only included below-cloud scavenging, whereas the new Wet Deposition module takes into account below-cloud and in-cloud scavenging. Both processes are implemented such that the effect of the saturation of rain droplets on the scavenging efficiency is included. A simple parameterization, based on the liquid water content data from ECMWF, is used to distinguish between regions in which respectively below-cloud or in-cloud scavenging occurs. In general, it is found that the combination of below-cloud and in-cloud scavenging increases the net scavenging process in the LOTOS-EUROS model simulations; hence the Wet Deposition fluxes are increased. These increased Wet Deposition fluxes in the model simulations are evaluated at the sites of the precipitation network in the Netherlands and show a better agreement as compared to results of simulations performed with the old Wet Deposition module. Finally the Wet Deposition fluxes are also evaluated at the sites of the European EMEP monitoring stations: a similar improvement is found again between the measurements and model results.
