supy 2026.4.3rc1

The SUEWS model that speaks Python

Surface Urban Energy and Water Balance Scheme

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What is SUEWS?

SUEWS is a neighbourhood/local-scale urban land surface model that simulates the urban radiation, energy and water balances using commonly measured meteorological variables and surface cover information. It uses an evaporation-interception approach (Grimmond and Oke, 1991), similar to that used in forests, to model evaporation from urban surfaces.

The model represents seven surface types -- paved, buildings, evergreen trees/shrubs, deciduous trees/shrubs, grass, bare soil and water -- and tracks the running water balance of the canopy, soil moisture, and horizontal water movement above and below ground.

SuPy (SUEWS in Python) provides the modern interface, wrapping a Fortran physics engine and integrating with the scientific Python ecosystem (pandas, NumPy, matplotlib).

Key Features

• Energy balance: net all-wave radiation, sensible and latent heat fluxes, storage heat flux, anthropogenic heat
• Water balance: soil moisture, infiltration, runoff, drainage, irrigation demand
• Radiation schemes: NARP, SPARTACUS-Surface (3D), BEERS (mean radiant temperature)
• Storage heat schemes: OHM, AnOHM, ESTM, EHC (explicit heat conduction)
• Building energy: STEBBS (Simple Thermal Energy Balance for Building Scheme)
• Python API: YAML configuration, pandas DataFrames, programmatic simulations
• CLI tools: suews-run, suews-validate, suews-convert, suews-schema

Quick Start

pip install supy

Run from the command line:

suews-run /path/to/config.yml

Or use the Python API:

from supy import SUEWSSimulation

sim = SUEWSSimulation.from_sample_data()
sim.run()
print(sim.output.summary())

Full documentation: docs.suews.io

Documentation

• Getting Started -- installation and first simulation
• Tutorials -- hands-on guides with sample data
• Input/Output Reference -- configuration and data formats
• Scientific Background -- physics schemes and parameterisations
• Community Forum -- questions, discussion, and support

Citation

If you use SUEWS in your research, please cite:

• Jarvi L, Grimmond CSB, Christen A (2011) The Surface Urban Energy and Water Balance Scheme (SUEWS): Evaluation in Los Angeles and Vancouver. J. Hydrol., 411, 219-237.
• Ward HC, Kotthaus S, Jarvi L, Grimmond CSB (2016) Surface Urban Energy and Water Balance Scheme (SUEWS): Development and evaluation at two UK sites. Urban Climate, 18, 1-32.

See CITATION.cff for machine-readable citation metadata.

Contributing

We welcome contributions from people who engage with the project. See CONTRIBUTING.md for guidelines. New contributors are encouraged to start on the Community Forum.

Development

git clone https://github.com/UMEP-dev/SUEWS.git && cd SUEWS
uv venv && source .venv/bin/activate
make dev && make test

• Onboarding Guide -- developer workflow and best practices
• Building Locally -- prerequisites, build commands, project structure
• Coding Guidelines -- style conventions and formatting tools

Licence

Mozilla Public License 2.0