Earth System Digital Twins

- Overview

The future of humanity is fundamentally tied to preserving the habitability of the planet through the protection of existing habitats and the sustainable use of natural resources. 

As satellite-based remote sensing of Earth matured in the post-Apollo era, the 1986 Bretherton Report outlined the need for systematic global measurements from space to support Earth system science.

The report calls for the development of an advanced information system - the Earth Observing System Data and Information System (EOSDIS). This will process and distribute data to describe and elucidate changes in Earth system processes through long-term global observations, subsequently enabling scientists to develop new models to simulate and predict future Earth system changes.

Originally designed to support models that describe Earth system dynamics and how Earth observations are linked to processes, states, and feedbacks in the Earth system, EOSDIS has evolved into today's Earth Information System (EIS).

- Earth Information System

The Earth system is composed of highly complex subsystems such as the atmosphere, hydrosphere, cryosphere, geosphere, and biosphere. These subsystems interact through coupling mechanisms at temporal and spatial scales, spanning 14-16 orders of magnitude from the molecular nanoscale to Rossby wave wavelengths.

These are highly complex nonlinear processes, and our understanding of the underlying physics is incomplete. Data assimilation frameworks that combine ocean, weather, and hydrological models with observations were developed and implemented with great success during the 1990s and 2000s, in particular improving weather forecasts.

Thus, thirty years after the Bretherton Report, the 2017 Decadal Survey of Earth Science and Space Applications explicitly recommends integrating models and all Earth observations to provide a holistic description of the Earth system.

EIS integrates observations and models to produce geospatial information that obeys physical laws and constraints. It monitors and interrogates our understanding of our home planet, detects and diagnoses changes to drive predictions, and explores decision-making strategies. Its predictions provide the basis for actionable Earth system science (or "Earth science applications").

- Digital Twin Earth

The National Aeronautics and Space Administration (NASA)’s classical Earth Information System (EIS) integrates models and remote-sensing data using assimilation techniques to produce geospatial information according to physical laws and meeting physical constraints. 

Digital Twins of Earth (DTE) are the “next-generation EIS”, leveraging a step-change in spatial resolution in Earth observations of a subset of key geophysical variables. These partial models provide a virtual representation of Earth processes and subcomponents of the Earth system. 

Understanding and quantifying uncertainty in DTE models and analyses is a scientific imperative - leading governmental agencies, together with international research programs, need to collaboratively define modern standards and new rules for scientific data exchange that facilitate rigorous and robust research and applications.
 

- Toward a Digital Twin Earth

A digital twin of Earth (DTE) is a virtual representation of Earth's systems and processes that uses a combination of physics-based models and Earth data to monitor and predict environmental and social changes. DTEs could be used to help with sustainable governance, such as monitoring and controlling global warming.

Here are some initiatives working towards a DTE:

• Destination Earth (DestinE): A European Commission initiative that aims to develop an accurate DTE to monitor and control global warming. DestinE DTs generate data that is stored in the DestinE Data Lake and accessible through the Destination Earth Service Platform (DESP).
• Earth System Digital Twins (ESDT): A NASA program that aims to develop technologies to integrate models of Earth and human activity to better understand the evolution of Earth's systems.
• Geo-Soft-CoRe: A project that aims to develop geoscientific software that integrates models of different aspects of the Earth system to help lay the foundation for a future DTE.

DTEs will also use artificial intelligence (A) and in situ measurements in addition to Earth observation data.