Coupled Ocean Atmosphere Processes and European Climate (COAPEC): improved understanding of the coupled climate system

COAPEC (http://coapec.nerc.ac.uk/) is a five-year Directed Science Programme funded by the Natural Environment Research Council (NERC). COAPEC is providing advances in understanding the mechanisms by which the ocean and atmosphere interact, how these processes are represented in state-of-the-art numerical climate models and how they determine the predictability of the climate system over seasonal-decadal timescales. Processes studied include the generation and propagation of salinity and heat anomalies in the North Atlantic, the influence of the thermohaline circulation and the role of storm tracks on European Climate. The influence of remote processes, including ocean-atmosphere coupling in tropical Atlantic warm events and Southern Ocean circulation are also being investigated. As part of the programme, new coupled models are being developed, including: a coupled hybrid isopycnic coordinate model; fast models for multi-ensemble runs to investigate model parameters space, using both high performance machines and spare home PC resources; a QG model to investigate high resolution ocean processes in coupled systems and validated ice models for coupled modelling. Underpinning research into improving the observational datasets, such as the SOC flux climatology, and into the influence of sea-ice observations in General Circulation Models is also being carried out as part of the programme. To place these advances into a socially relevant context, COAPEC is also investigating the methods for using, and economic benefits of, climate forecasts at seasonal timescales for the UK health sector and the UK energy industry

High resolution global climate modelling; the UPSCALE project, a large simulation campaign

The UPSCALE (UK on PRACE: weather-resolving Simulations of Climate for globAL Environmental risk) project constructed and ran an ensemble of HadGEM3 (Hadley Centre Global Environment Model 3) atmosphere only global climate simulations over the period 1985–2011, at resolutions of N512 (25 km), N216 (60 km) and N96 (130 km) as used in current global weather forecasting, seasonal prediction and climate modelling respectively. Alongside these present climate simulations a parallel ensemble looking at extremes of future climate was run, using a timeslice methodology to consider conditions at the end of this century. These simulations were primarily performed using a 144 million core hour, single year grant of computing time from PRACE (the Partnership for Advanced Computing in Europe) in 2012, with additional resources supplied by the Natural Environment Research Council (NERC) and the Met Office. Almost 400 terabytes of simulation data were generated on the HERMIT supercomputer at the High Performance Computing Center Stuttgart (HLRS), and transferred to the JASMIN super-data cluster provided by the Science and Technology Facilities Council Centre for Data Archival (STFC CEDA) for analysis and storage. In this paper we describe the implementation of the project, present the technical challenges in terms of optimisation, data output, transfer and storage that such a project involves and include details of the model configuration and the composition of the UPSCALE data set. This data set is available for scientific analysis to allow assessment of the value of model resolution in both present and potential future climate conditions

Implementation of U.K. Earth system models for CMIP6

We describe the scientific and technical implementation of two models for a core set of experiments contributing to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The models used are the physical atmosphere-land-ocean-sea ice model HadGEM3-GC3.1 and the Earth system model UKESM1 which adds a carbon-nitrogen cycle and atmospheric chemistry to HadGEM3-GC3.1. The model results are constrained by the external boundary conditions (forcing data) and initial conditions.We outline the scientific rationale and assumptions made in specifying these. Notable details of the implementation include an ozone redistribution scheme for prescribed ozone simulations (HadGEM3-GC3.1) to avoid inconsistencies with the model's thermal tropopause, and land use change in dynamic vegetation simulations (UKESM1) whose influence will be subject to potential biases in the simulation of background natural vegetation.We discuss the implications of these decisions for interpretation of the simulation results. These simulations are expensive in terms of human and CPU resources and will underpin many further experiments; we describe some of the technical steps taken to ensure their scientific robustness and reproducibility

Decadal predictions with the HiGEM high resolution global coupled climate model: description and basic evaluation

This paper describes the development and basic evaluation of decadal predictions produced using the HiGEM coupled climate model. HiGEM is a higher resolution version of the HadGEM1 Met Office Unified Model. The horizontal resolution in HiGEM has been increased to 1.25◦ × 0.83◦ in longitude and latitude for the atmosphere, and 1/3◦ × 1/3◦ globally for the ocean. The HiGEM decadal predictions are initialised using an anomaly assimilation scheme that relaxes anomalies of ocean temperature and salinity to observed anomalies. 10 year hindcasts are produced for 10 start dates (1960, 1965,..., 2000, 2005). To determine the relative contributions to prediction skill from initial conditions and external forcing, the HiGEM decadal predictions are compared to uninitialised HiGEM transient experiments. The HiGEM decadal predictions have substantial skill for predictions of annual mean surface air temperature and 100 m upper ocean temperature. For lead times up to 10 years, anomaly correlations (ACC) over large areas of the North Atlantic Ocean, the Western Pacific Ocean and the Indian Ocean exceed values of 0.6. Initialisation of the HiGEM decadal predictions significantly increases skill over regions of the Atlantic Ocean,the Maritime Continent and regions of the subtropical North and South Pacific Ocean. In particular, HiGEM produces skillful predictions of the North Atlantic subpolar gyre for up to 4 years lead time (with ACC > 0.7), which are significantly larger than the uninitialised HiGEM transient experiments

“I Am Not Taking Sides as a Female At All”:Co-Facilitation and Gendered Positioning in a Domestic Abuse Perpetrator Program

The facilitation of domestic abuse perpetrator programs (DAPPs) by mixed gender co-facilitation pairs brings different facilitator perspectives and enables the modeling of egalitarian and respectful male-female relationships. This study analyzed 22 video and audio recordings of community-based DAPP groups featuring male participants, and male and female facilitators. Using thematic analysis, we aimed to understand how facilitators engaged participants and whether the facilitator’s gender affected this. We found an asymmetry in the positioning of the facilitators. Group participants challenged both facilitators, but especially the female facilitators. Facilitator strategies toward behavior change included softening direct challenges (female facilitators) and mobilizing the shared category of men (male facilitators). Implications from this study are for reflective practice in facilitator management and supervision specifically focused on gendered power dynamics. Skilled facilitation is key to behavior change and the gendered interplay within groups may be a crucial element in the reduction of interpersonal violence and abuse

Diagnosis of mixing between middle latitudes and the polar vortex from tracer-tracer correlations

A method is introduced for diagnosing mixing between the polar vortex and midlatitudes from tracer data. Tracers with different photochemical activities and lifetimes usually exhibit curved tracer-tracer correlation functions on an isentropic surface. The effect of mixing events is to populate the inner side of such a curve. Using simultaneous measurements of trace gases or model results, we exploit this process to calculate the distribution of recent origins in tracer space prior to such a mixing event. The method relies on both hemispheric and local data and is applicable to situations where mixing is nonlocal in tracer space. It is applied to measurements taken during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment/Third European Stratospheric Experiment on Ozone 2000 (SOLVE/THESEO 2000) winter campaign and to a chemical transport model simulation covering the same winter. In one of the cases studied, a vortex breakup and subsequent remerger of the vortex fragments in March 2000 results in significant diagnosed mixing. In a further example, an elongated filament shed off the polar vortex is characterized by anomalous composition. For the two high-altitude aircraft flights of the SOLVE campaign that probe the vortex boundary, a correspondence is found for mixing diagnosed in the measurements and in the model. Mixing timescales considered here are given by the life span of planetary waves, up to a few weeks

Diagnosis of mixing between middle latitudes and the polar vortex from tracer-tracer correlations

A method is introduced for diagnosing mixing between the polar vortex and midlatitudes from tracer data. Tracers with different photochemical activities and lifetimes usually exhibit curved tracer-tracer correlation functions on an isentropic surface. The effect of mixing events is to populate the inner side of such a curve. Using simultaneous measurements of trace gases or model results, we exploit this process to calculate the distribution of recent origins in tracer space prior to such a mixing event. The method relies on both hemispheric and local data and is applicable to situations where mixing is nonlocal in tracer space. It is applied to measurements taken during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment/Third European Stratospheric Experiment on Ozone 2000 (SOLVE/THESEO 2000) winter campaign and to a chemical transport model simulation covering the same winter. In one of the cases studied, a vortex breakup and subsequent remerger of the vortex fragments in March 2000 results in significant diagnosed mixing. In a further example, an elongated filament shed off the polar vortex is characterized by anomalous composition. For the two high-altitude aircraft flights of the SOLVE campaign that probe the vortex boundary, a correspondence is found for mixing diagnosed in the measurements and in the model. Mixing timescales considered here are given by the life span of planetary waves, up to a few weeks

Decadal climate prediction (project GCEP)

Decadal prediction uses climate models forced by changing greenhouse gases, as in the International Panel for Climate Change, but unlike longer range predictions they also require initialization with observations of the current climate. In particular, the upper-ocean heat content and circulation have a critical influence. Decadal prediction is still in its infancy and there is an urgent need to understand the important processes that determine predictability on these timescales. We have taken the first Hadley Centre Decadal Prediction System (DePreSys) and implemented it on several NERC institute compute clusters in order to study a wider range of initial condition impacts on decadal forecasting, eventually including the state of the land and cryosphere. The eScience methods are used to manage submission and output from the many ensemble model runs required to assess predictive skill. Early results suggest initial condition skill may extend for several years, even over land areas, but this depends sensitively on the definition used to measure skill, and alternatives are presented. The Grid for Coupled Ensemble Prediction (GCEP) system will allow the UK academic community to contribute to international experiments being planned to explore decadal climate predictability