Environmental Modelling & Software 2025

Democratizing Urban Climate Modeling

Integration and execution of Community Land Model Urban (CLMU) in a containerized environment.

J. Yu, Y. Sun, S. Lindley, C. Jay, D.O. Topping, K.W. Oleson, Z. Zheng

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The Challenge

Barriers to Urban Climate Science

The Community Land Model Urban (CLMU) is a powerful process-based numerical model for simulating interactions between the atmosphere and urban surfaces. However, traditional usage presents significant hurdles:

  • Complex Installation: Requires specific UNIX-style OS, Fortran compilers, and strict library dependencies.
  • Intricate Configuration: Users must master machine environment settings, often leading to tedious debugging.
  • Data Heavy: Generating model inputs requires navigating complex urban surface and atmospheric forcing data.

Critical Impact

Rapid urbanization has intensified the need to understand micro-climates.

Thermal Stress

Rising urban temperatures pose severe risks to resident health. This toolkit enables precise simulation of Human Thermal Stress and Urban Heat Island (UHI) effects to guide adaptation strategies.

The Solution: A Dual-Toolkit Approach

01. CLMU-App

Containerized Execution

An OS-independent Docker container that packages code and dependencies into a standardized unit.

  • Run Anywhere: Compatible with Windows, macOS (Apple Silicon), and Linux.
  • Standardized: Uses a stable version of CLM 5.0 with identical physical processes.
  • Zero Compilation: Just pull the image and run.
> docker pull envdes/clmu-app:1.0
> docker run -hostname clmu-app ...

02. Pyclmuapp

Python Interface

A Python package to streamline execution and automate data creation (Surface & Forcing).

  • Automated Workflow: Manages configuration, case creation, and execution.
  • Data Generation: Creates surface data and atmospheric forcing data (ERA5) for any location.
  • Scenario Testing: Easily modifies parameters (e.g., roof albedo) for adaptation studies.
from pyclmuapp import usp_clmu
usp = usp_clmu()
usp.run(case_name="London_Test", ...)

Presentation

Project Overview Slides

Detailed breakdown of the integration, execution flow, and validation results.

Case Study

Cool Roof Adaptation

Simulating the implementation of cool roofs (increasing albedo by 0.2) demonstrates a significant reduction in urban air temperatures, particularly during peak daytime hours. This highlights the toolkit's capability to evaluate climate adaptation strategies effectively.

Energy Balance

Successfully models UHI effects. Outputs include sensible, latent, and anthropogenic heat fluxes validation against King's College London data.

Water Balance

Simulates urban runoff and evaporation, aiding in flood risk assessment and water stewardship planning.

Cloud Support

Now supported by AWS. Run local-scale (1KM) simulations directly in the browser without local installation.