Title
Implementation and evaluation of pH-dependent cloud chemistry and wetdeposition in the chemical transport model REM-Calgrid
Author
Banzhaf, S.
Schaap, M.
Kerschbaumer, A.
Reimer, E.
Stern, R.
van der Swaluw, E.
Builtjes, P.
Publication year
2012
Abstract
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.
Subject
Earth & Environment
CAS - Climate, Air and Sustainability
EELS - Earth, Environmental and Life Sciences
Climate
Energy / Geological Survey Netherlands
Ammonia
Aqueous-phase chemistry
Droplet pH sensitivity
Model evaluation
Nitrogen deposition
Sulphate
Sulphur deposition
Wet deposition
Droplet pH sensitivity
Model evaluation
Nitrogen deposition
Sulphates
Sulphur deposition
Wet deposition
Ammonia
Deposition
Drops
Mean square error
Models
Nitrogen compounds
Sulfur
Sulfur dioxide
pH
nitrogen
rain
sulfate
ammonia
chemical composition
cloud
error analysis
nitrogen
pH
raindrop
scavenging (chemistry)
sensitivity analysis
sulfate
sulfur
sulfur dioxide
wet deposition
aqueous solution
article
atmospheric deposition
chemical composition
cloud
concentration (parameters)
environmental impact
observational study
pH
priority journal
sensitivity analysis
wet deposition
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http://resolver.tudelft.nl/uuid:c50e9be3-bfb6-4c7a-b60d-72e22005cf98
TNO identifier
446759
ISSN
1352-2310
Source
Atmospheric Environment, 49, 378-390
Document type
article