edu.ucar.opensky::articles:18858 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T02:43:11.203343 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7vh5qhc D-region ion-neutral coupled chemistry (Sodankylä Ion Chemistry, SIC) within the Whole Atmosphere Community Climate Model (WACCM 4) -- WACCM-SIC and WACCM-rSIC 2016-09-12T00:00:00Z publication https://n2t.org/ark:/85065/d7vh5qhc https://doi.org/10.5194/gmd-9-3123-2016 Kovács, T. author Plane, J. M. C. author Feng, W. author Nagy, T. author Chipperfield, M. P. author Verronen, P. T. author Andersson, M. E. author Newnham, D. A. author Clilverd, M. A. author Marsh, Daniel author UCAR/NCAR - Library publisher This study presents a new ion-neutral chemical model coupled into the Whole Atmosphere Community Climate Model (WACCM). The ionospheric D-region (altitudes similar to 50-90 km) chemistry is based on the Sodankyla Ion Chemistry (SIC) model, a one-dimensional model containing 307 ion-neutral and ion recombination, 16 photodissociation and 7 photoionization reactions of neutral species, positive and negative ions, and electrons. The SIC mechanism was reduced using the simulation error minimization connectivity method (SEM-CM) to produce a reaction scheme of 181 ion-molecule reactions of 181 ion-molecule reactions of 27 positive and 18 negative ions. This scheme describes the concentration profiles at altitudes between 20 km and 120 km of a set of major neutral species (HNO3, O-3, H2O2, NO, NO2, HO2, OH, N2O5) and ions (O-2(+), O-4(+), NO+, NO+ (H2O), O-2(+) (H2O), H+ (H2O), H+ (H2O)(2), H+ (H2O)(3), H+ (H2O)(4), O-3(-), NO2-, O-, O-2, OH--, O-2(-) (H2O), O-2(-) (H2O)(2), O-4(-), CO3-, CO3- (H2O), CO4-, HCO3-, NO2-, NO3-, NO3- (H2O), NO3- (H2O)(2), NO3- (HNO3), NO3- (HNO3)(2), Cl-, ClO-, which agree with the full SIC mechanism within a 5% tolerance. Four 3-D model simulations were then performed, using the impact of the January 2005 solar proton event (SPE) on D-region HOx and NOx chemistry as a test case of four different model versions: the standard WACCM (no negative ions and a very limited set of positive ions); WACCM-SIC (standard WACCM with the full SIC chemistry of positive and negative ions); WACCM-D (standard WACCM with a heuristic reduction of the SIC chemistry, recently used to examine HNO3 formation following an SPE); and WACCM-rSIC (standard WACCM with a reduction of SIC chemistry using the SEM-CM method). The standard WACCM misses the HNO3 enhancement during the SPE, while the full and reduced model versions predict significant NOx, HOx and HNO3 enhancements in the mesosphere during solar proton events. The SEM-CM reduction also identifies the important ion-molecule reactions that affect the partitioning of odd nitrogen (NOx), odd hydrogen (HOx) and O-3 in the stratosphere and mesosphere. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Author(s) 2016. This work is distributed under the Creative Commons Attribution 3.0 License None eng geoscientificInformation