Hector – a computationally-efficient, open-source, community-based global

and regional climate emulator

Corinne Hartin, Ben Bond-Lamberty, Robert Link, Ben Vega-Westhoff2, Ryan Sriver2,

Abigail Snyder, Ben Kravitz and Kate Calvin

Pacific Northwest National Laboratory/Joint Global Change Research Institute

2University of Illinois

Corinne.Hartin@pnnl.gov

U.S. Department of Energy, Office of Science, as part of research in Multi-Sector Dynamics, Earth and Environmental System Modeling Program

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What is Climate Emulation?

reproduced from Provenzale, A. (2014)

An emulator is a fast approximation to a computationally expensive model that can be used as a surrogate for the model, to quantify uncertainty or to improve process understanding. (Holden et al., 2014)

Earth System Models (ESMs) are state of the art tools for climate predictions.

However, due to their computational demands they limit the range of studies that can be conducted with them.

What if we wanted to know average global mean temperature projections under other scenarios?

What if we wanted to investigate uncertainty across the climate and carbon systems?

Or the probability of exceeding a particular threshold?

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What is Climate Emulation?

reproduced from Provenzale, A. (2014)

Idealized Comprehensive

FAIR

IPCC IR

Hector

MAGICC

ACC2

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Simple Climate Carbon-Cycle Models

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Meinshausen et al., 2011

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• Free and open-source

• Community model

www.github.com/JGCRI/hector

Easy to use and well documented

Hartin et al., 2015 – GMD

Hartin et al., 2016 – BGS

pyhector

rhector

Hector GAMS

Issue tracking

Overview of Hector – Comprehensive Simple Climate Carbon-Cycle Model

• Complexity only where warranted

DOECLIM, BRICK

• Modular

Components can be enabled/disabled via inputs

E.g., test two different ocean submodelsagainst each other

• Modern, clean code structure

E.g., coupler enforces unit checking between submodels

Overview of Hector v2.0 - Climate and Carbon Cycle

CO2, CH4, N2O, halocarbons, BC, OC,

sulphate aerosols, strat H2O, trop O3

NPP,

RH,

carbon

fluxespH, CaCO3 saturations, carbon

fluxes

1D diffusive ocean – DOECLIM

for heat transport

Hartin et al., 2015, 2016

www.Github.com/JGCRI/hector

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Overview of Hector v2.0 - Climate and Carbon Cycle

Hartin et al., 2015 – GMD; Hartin et al., 2016 – BGS

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Complex Model Emulation – CMIP5

Global Mean Temperature Atmospheric CO2

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Complex Model Emulation – CMIP5

Global Mean Temperature

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Probabilistic Capabilities

Global Mean Temperature

HadCRUT

Global Sea-Level Rise

Church and White

Vega-Westhoff et al., submitted to Earth’s Future, 2018

low probability/high impact events

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Regional Climate Emulation

Multiple realizations over College Park MD with realistic variability of the underlying ESM emulated - CESM1.

www.github.com/JGCRI/fldgen

Link et al., 2018 – GMDD

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Current Hector Research

• Understanding the response of SCMs

• Probability of ocean acidification

• Updating Hector

Land biomes – permafrost

Schwarber et al., in review - ESD

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Current Hector Research

• Understanding the response of SCMs

• Probability of ocean acidification

• Updating Hector

Land biomes – permafrost

• Coupled to GCAM

Investigate two-way feedbacks

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Hector Capabilities

• All model code and tools are open source

Transparent and freely available

Issue tracking

Reproducible code and workflow

“How-to-guides”

Vignettes

• Hector ecosystem

Emulate any model or dataset of interest

Global

Regional

Uncertainty and sensitivity analysis

Solve for an emission pathway

• Easy to couple

GCAM, DOECLIM, BRICK

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Future Community Involvement

• What would the IAM community would like to see in the future?

• www.github.com/JGCRI/hector

• www.github.com/JGCRI/fldgen

• www.github.com/openclimatedata/pyhector

Thank you

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Corinne.Hartin@pnnl.gov