Translating Process Understanding to Improve Climate Models Workshop Products

sea surface temperature

Schedule

Thursday, October 15, 
08:00 – 19:00

Friday, October 16, 
08:00 – 17:00

Workshop Products

One of the outcomes from the workshop was a white paper, released August 2016, summarizing questionnaire responses, workshop presentations, discussions, and recommendations to inform the broad research community and agency considerations.

Another product that stemmed from workshop discussions was examples of some of the types of processes that participants thought were in a reasonable state of readiness for translation into climate model improvements, including information on the motivation for addressing them. In addition to improving specific processes within the model, there was a stated need to incorporate new model capabilities for missing processes and components. The workshop identified many different opportunities for model improvement by incorporating new process understanding. Some of these opportunities are summarized in Table 1, but any future activities should not be limited to the topics discussed in this document or at the workshop given that the interests of only a subset of the community have been considered thus far.

Table 1. Selected set of examples of the type of processes/phenomena identified at the workshop that participants felt were in a reasonable state of readiness for translation into climate model improvements. 

Process / Phenomenon Potential Bias Improvement Motivation References

Estuarine/fjord – ocean interactions

Salinity near estuaries and rivers; coastal ocean stratification

Allows for riverine nutrient & heat transport; impacts coastal biogeochemistry

Geyer and MacCready (2014), Horner-Devine et al. (2015)

Atmospheric boundary layer and land surface interaction

Forecast biases on sub-seasonal timescales

Improvements in soil moisture coupling to atmospheric boundary layer

Kumar et al. (2014)

Equatorial mixing

Cold tongue bias

Can influence simulated variability (ENSO), surface coupling

Sasaki et al. (2013)

Eddy life cycle and energetics

Mixed layer depth; primary production

Controls on vertical ocean exchange, upper ocean stratification, non-Newtonian mixing parameterization

Mana and Zanna (2014), Jansen et al. (2015b)

Eastern boundary upwelling

Warm regional SST bias

Improve coupled interactions and feedbacks; impacts on BGC

Small et al. (2015)

Western boundary currents

SST, surface heat fluxes, and oceanic heat transport

Potential links to AMOC, decadal variability

Carton et al. (2014), Hu et al. (2015)

Swell and Langmuir turbulence

Southern ocean mixed layer bias

Potentially influence ocean transient response

Fan and Griffies (2014)

Shelf-open ocean exchange

Ocean water mass and density structure

Potential influence on shelf biogeochemical processes including upwelling driven primary production, hypoxia, and low pH events

Bryan et al. (2015)

Gravity wave drag

Large-scale atmospheric circulation

Improved wind stress and coupling

Geller et al. (2013)

Topographic wave drag

Internal wave representation and large-scale ocean circulation

Improved energy balance representation in ocean interior

Trossman et al. (2016)

Atmospheric moist convection

Diurnal cycle of precipitation, MJO

Improvements to tropical climate and variability

Pearson et al. (2014)

Mixed-phase clouds

Radiation biases, precipitation biases

Potential influence on cloud feedbacks

Pithan et al. (2014)

Glacier/ice shelf - ocean interaction

Ocean influence on glacial and ice-sheet retreat

 

Potential impact of increased glacial meltwater discharge on ocean circulation including AMOC and of ocean dynamics on variable submarine melting of glaciers/ice shelves

Straneo and Heimbach 2013

 

Snow on sea ice

Snow and albedo biases

Influences polar feedbacks

Hezel et al. (2012)

 

References:

Bryan, F., J. Dennis, P. MacCready, and M. Whitney, 2015: Final report collaborative project. Improving the representation of coastal and estuarine processes in Earth system models. NCAR Technical Report 1226494, doi:10.2172/1226494

Carton, J. A., S. A. Cunningham, E. Frajka-Williams, Y.-O. Kwon, D. P. Marshall, and R. Msadek, 2014: The Atlantic overturning circulation: More evidence of variability and links to climate. Bull. Amer. Meteorol. Soc.95, 163, doi:10.1175/BAMS-D-13-00234.1.

Clement, A. C., R. Burgman, and J. R. Norris, 2009: Observational and model for positive low-level cloud feedback. Science, 325, 460-464, doi:10.1126/science.1171255.

Fan, Y., and S. M. Griffies, 2014: Impacts of parameterized Langmuir turbulence and nonbreaking wave mixing in global climate simulations. J. Climate27, 4752-4775, doi:10.1175/JCLI-D-13-00583.1.

Geller, M. A., and Coauthors, 2013: A comparison between gravity wave momentum fluxes in observations and climate models. J. Climate26, 6383-6405, doi:10.1175/JCLI-D-12-00545.1.

Geyer, W. R., and P. MacCready, 2014: The estuarine circulation. Ann. Rev. Fluid Mech., 46, 175–197, doi:10.1146/annurev-fluid-010313-141302.

Hezel, P. J., X. Zhang, C. M. Bitz, B. P. Kelly, and F. Massonnet, 2012: Projected decline in spring snow depth on Arctic sea ice caused by progressively later autumn open ocean freeze-up this century. Geophys. Res. Lett., 39, L17505, doi:10.1029/2012GL052794.

Horner-Devine, A. R., R. D. Hetland, and D. G. MacDonald, 2015. Mixing and transport in coastal river plumes. Ann. Rev. Fluid Mech., 47, 569-594, doi:10.1146/annurev-fluid-010313-141408

Hu, D., and Coauthors, 2015: Pacific western boundary currents and their roles in climate. Nature, 522, 299-308, doi:10.1038/nature14504.

Jansen, M., A. Adcroft, R. Hallberg, and I. M. Held, 2015b: Parameterization of eddy fluxes based on a mesoscale energy budget. Ocean Modell., 92, 28-41, doi:10.1016/j.ocemod.2015.05.007.

Junker, T., M. Schmidt, and V. Mohrholz, 2015: The relation of wind stress curl and meridional transport in the Benguela upwelling system. J. Mar. Syst., 143, 1-6, doi:10.1016/j.jmarsys.2014.10.006.

Kumar, S., and Coauthors 2014: Effects of realistic land surface initializations on subseasonal to seasonal soil moisture and temperature predictability in North America and in changing climate simulated by CCSM4. J. Geophys. Res.: Atmos.119, 13,250-12,270, doi:10.1002/2014JD022110.

Kemppinen, O., T. Nousiainen, and G. Y. Jeong, 2015: Effects of dust particle internal on light scattering. Atmos. Chem. Phys., 15, 12011-12027, doi:10.5194/acp-15-12011-2015.

Mana, P. G. L, and L. Zanna, 2014: Toward a stochastic parametrization of ocean mesoscale eddies. Ocean Modell., 79, 1-20, doi:10.1016/j.ocemod.2014.04.002.

Pearson, K. J., G. M. S. Lister, C. E. Birch, R. P. Allan, R. J. Hogan, and S. J. Woolnough, 2014: Modelling the diurnal cycle of tropical convection across the ‘grey zone’. Quart. J. Roy. Meteorol. Soc., 140, 491-499, doi:10.1002/qj.2145.

Pithan, F., B. Medeiros, and T. Mauritsen, 2014: Mixed-phase clouds cause climate model biases in Arctic wintertime temperature inversions. Climate Dyn.43, 289-303, doi:10.1007/s00382-013-1964-9.

Sasaki, W., K. J. Richards, and J. J. Luo, 2013: Impact of vertical mixing induced by small vertical scale structures above and within the equatorial thermocline on the tropical Pacific in a CGCM. Climate Dyn., 41, 443-453, doi:10.1007/s00382-012-1593-8.

Straneo, F. and Heimbach, P., 2013. North Atlantic warming and the retreat of Greenland's outlet glaciers. Nature, 504, 36-43, doi:10.1038/nature12854.

Trossman, D. S., B. K. Arbic, S. T. Garner, J. A. Goff, S. R. Jayne, E. J. Metzger, and A. J. Wallcraft, 2013: Impact of parameterized lee wave drag on the energy budget of an eddying global ocean model. Ocean Modell., 72, 119-142, doi:10.1016/j.ocemod.2013.08.006