Synopsis

VolMIP is a protocol-driven international project aiming at coordinating the activities of different Research Institutes involved in numerical climate modelling focused on a multi-model assessment of climate models' performance under strong volcanic forcing conditions.

Experiments

Tier 1(core) Tier 2 Tier 3

 

Schematic of VolMIP experiments tackling different aspects of the climatic response to volcanic forcing. 1: volc-long-eq, 2: volc-pinatubo-full, 3: volc-pinatubo-surf, 4: volc-pinatubo-strat, 5: volc-long-hlN/-hlS, 6: volc-cluster-ctrl/-mill/-21C, 7: volc-pinatubo-slab, 8: volc-pinatubo-ini

 

VolMIP defines a set of idealized volcanic perturbations based on historical eruptions.

Volcanic forcing is derived from radiation parameters of documented eruptions and the experiments neglect information about the actual climate conditions when these events occurred. The experiments are designed as ensemble simulations, with sets of initial climate states sampled from an unperturbed preindustrial simulation. The selection of initial conditions specifically accounts for the concomitant phasing of two dominant modes of climate variability: the El Nino-Southern Oscillation - the most important source of interannual climate variability - and the Atlantic meridional overturning circulation - a measure of the strength of the oceanic thermohaline circulation.

 

VolMIP experiments are designed based on a multifold strategy:

volc-short: these experiments focus on the systematical assessment of uncertainty and inter-model differences in the seasonal-to-interannual climatic response to an  idealized 1991 Pinatubo-like  eruption, chosen as representative of the largest magnitude of volcanic events that occurred during the observational period.

volc-long: these experiments are designed to systematically investigate inter-model differences in the long-term (up to the decadal time scale) dynamical climate response to volcanic eruptions that are characterized by a high signal-to-noise ratio in the response of global-average surface temperature.

volc-cluster:designed to investigate the climatic response to a close succession of strong volcanic eruptions (so-called "volcanic cluster")..

The main goal of volc-long and volc-cluster experiments is to assess how volcanic perturbation signals propagate within the simulated climates, e.g., into the subsurface ocean, the associated determinant processes and their representation across models.
 

Identification of consensus forcing input data for both types of experiments is an integral part of VolMIP

Several climate modeling Centers performed a coordinated assessment of radiative forcing uncertainties for volc-long-eq (Tambora-like experiment) using aerosol climate models. The experimental protocol is available here.

Preliminary results showed large uncertainties in the derived estimate of volcanic forcing parameters. We concluded that the existing uncertainties prevent the identification, within the time constraints of the CMIP6 schedule, of a single consensus forcing estimate for a given volcanic eruption based on a multi-model ensemble with current chemistry climate models.
 
Therefore, VolMIP proposes for the volc-long and volc-cluster experiments forcing data sets constructed with the Easy Volcanic Aerosol (EVA) module (Toohey et al., 2016, here).

Published on  16.01.2018