The SOCOL version 3.0 chemistry–climate model: description, evaluation, and implications from an advanced transport algorithm

Abstract

Abstract. We present the third generation of the coupled chemistry-climate model (CCM) SOCOL (modeling tools for studies of SOlar Climate Ozone Links). The most notable modifications compared to the previous model version are (1) the dynamical core has been updated with the fifth generation of the middle-atmosphere general circulation model MA-ECHAM (European Centre/HAMburg climate model), and (2) the advection of the chemical species is now calculated by a mass-conserving and shape-preserving flux-form transport scheme instead of the previously used hybrid advection scheme. The whole chemistry code has been rewritten according to the ECHAM5 infrastructure and transferred to Fortran95. In contrast to its predecessors, SOCOLvs3 is now fully parallelized. The performance of the new SOCOL version is evaluated on the basis of transient model simulations (1975-2004) with different horizontal (T31 and T42) resolutions, following the approach of the CCMVal-1 model validation activity. The advanced advection scheme significantly reduces the artificial loss and accumulation of tracer mass in regions with strong gradients that was observed in previous model versions. Compared to its predecessors, SOCOLvs3 generally shows more realistic distributions of chemical trace species, especially of total inorganic chlorine, in terms of the mean state, but also of the annual and interannual variability. Advancements with respect to model dynamics are for example a better representation of the stratospheric mean state in spring, especially in the Southern Hemisphere, and a slowdown of the upward propagation in the tropical lower stratosphere. Despite a large number of improvements model deficiencies still remain. Examples include a too-fast vertical ascent and/or horizontal mixing in the tropical stratosphere, the cold temperature bias in the lowermost polar stratosphere, and the overestimation of polar total ozone loss during Antarctic springtime.

Review of the global models used within phase 1 of the Chemistry–Climate Model Initiative (CCMI)

“…MRI-ESM1r1 v1.1 Yukimoto et al (2012Yukimoto et al ( , 2011, MRI Deushi andShibata (2011) MOCAGE v2.15.1 Josse et al (2004); Guth et al (2016) N/A SOCOL v3 Revell et al (2015), SOCOL v2.0 Stenke et al (2013) (Schraner et al, 2008) TOMCAT v1.8 Chipperfield (1999Chipperfield ( , 2006 for different processes (Table S6). In addition, most models now use the Gregorian or the 365-day calendars (whereas in CCMVal-2, for reasons of easier handling of averages and climatologies, often a 360-day calendar was used).…”

“…Since CCMVal-2, the SOCOL model (SOlar Climate Ozone Links; Stenke et al, 2013) has significantly changed. SOCOLv2, which participated in CCMVal-2, was a combination of the GCM MA-ECHAM4 (Manzini et al, 1997) and the CTM MEZON (Rozanov et al, 1999;Egorova et al, 2003), while the third and current version, SOCOLv3, is based on MA-ECHAM5 .…”

Impact of geomagnetic excursions on atmospheric chemistry and dynamics

“…Versions 1 and 2 of SOCOL, based on MA-ECHAM4, have been validated by Egorova et al (2005) and Schraner et al (2008). SOCOLv3 was recently developed by Stenke et al (2013), who coupled the chemistry and dynamics routines to MA-ECHAM 5.4.00, improved the advection scheme for chemical species and enabled it to be fully parallelized. SOCOLv3 improves some previous deficiencies in chemical transport.…”

An upper-branch Brewer–Dobson circulation index for attribution of stratospheric variability and improved ozone and temperature trend analysis

“…To investigate temperature and ozone variability in the stratosphere and mesosphere at all latitudes, without data gaps, we simulate historical ozone and temperature variations using the chemistry-climate model (CCM) SOlar Climate Ozone Links (SOCOL, version 3; Stenke et al, 2013) in specifieddynamics mode, whereby the vorticity and divergence of the wind fields and temperature, and the logarithm of surface pressure are "nudged" using the ERA-Interim reanalysis (Dee et al, 2011(Dee et al, ) between 1983(Dee et al, and 2012 (Revell et al, 2015), except for the solar irradiance input, for which we use the Spectral And Total Irradiance REconstruction -Satellite era (SATIRE-S) model (Krivova et al, 2003;Yeo et al, 2014). In the following we focus on temperature and ozone variables; the former is nudged, while the latter is simulated by the CCM SOCOL.…”