pyrolib 0.2.0

Python tools for MesoNH-Blaze model

pyrolib

pyrolib is a tool library for Méso-NH/Blaze model. pyrolib provides python tools for the following purposes:

• Generation of the FuelMap.nc file by using a Méso-NH namelist and the initialisation file of a Méso-NH/Blaze run.
• FireFlux I exeprimental fire data processing.
• Development of numerical methods for the Blaze fire model.

Installation

Install pyrolib from PyPI's:

pip install pyrolib

Usage

pyrolib is separated into several sub-libraries for each of the objectives mentioned above, respectively:

• pyrolib.fuelmap
• pyrolib.firefluxpost
• pyrolib.blaze

Fuel database

pyrolib relies on a fuel container object called a FuelDatabase. A FuelDatabase is a 2 level nested dictionary-like class. The first level corresponds to an explicit fuel name (like "tall_grass"). This fuel can be described by several methods that are related to a rate of spread model (for example Rothermel or Balbi). Each description is relatde to a Fuel class (RothermelFuel or BalbiFuel) are constitute the second level of the database.

The FireFluxI FuelDatabase contains for example the following:

* FireFluxI
    < tall_grass > available for:
      - BalbiFuel fuel class

The list of FuelDatabase contained in pyrolib can be accessed through the cli pyrolib-fm list-fuel-databases.

A user database can be saved in a .yml file. See example examples/fuel_database.

How to

generate the FuelMap.nc file

The objective of this part is to easily create a fuel file for a Méso-NH/Blaze run. This file is always named FuelMap.nc. It needs to contain a 2D map on the fire grid for the following fields :

• fuel type,
• every fuel property that are compliant with the selected rate of spead parameterization in the Méso-NH/Blaze namelist,
• ignition time,
• walking ignition time.

pyrolib.fuelmap provides tools for the generation of every Fuelmap.nc component. Some Méso-NH files are needed to complete the process. A typical Méso-NH run directory should look like

run_MNH/
├─ EXSEG1.nam
├─ Init_file.des
├─ Init_file.nc

Some Méso-NH files are included in the example directory to run examples.

simplecase.py example provides basic steps to create a fuel map using pyrolib tools. Some operations can be accelerated with numba. pyrolib can check if numba is installed in your environment. If not, pyrolib will show a warning message. In this example, the Méso-NH domain is $(Nx, Ny) = (20, 20)$ with $\Delta_x = \Delta_y = 25$m. The fire mesh is refined with $\Gamma_x = \Gamma_y = 5$. The goal of this example is to set:

• a rectangle burnable area defined by $50 \leqslant x \leqslant 450$ and $50 \leqslant y \leqslant 450$,
• an ignition patch is set at $t = 10$s with $100 \leqslant x \leqslant 105$ and $245 \leqslant y \leqslant 255$.

As the rate of spread model defined in the Méso-NH namelist, the BalbiFuel class shall be used to define the fuel properties.

"""simplecase.py

Use an existing fuel database and create a simple fuelmap
"""
from pyrolib.fuelmap import FuelDatabase, FuelMap

# create fuel db
my_db = FuelDatabase()

# load existing database
my_db.load_fuel_database("FireFluxI")

# create a FuelMap
my_fuelmap = FuelMap(fuel_db=my_db)

# add a fuel patch of the tall grass fuel from the FireFluxI database
## to show the available fuel keys of the database, use print(my_db)
my_fuelmap.add_fuel_rectangle_patch(xpos=[50, 450], ypos=[50, 450], fuel_key="FireFluxI_tall_grass")

# add a ignition patch
my_fuelmap.add_ignition_rectangle_patch(xpos=[100, 105], ypos=[245, 255], ignition_time=10)

# dump for mesonh
my_fuelmap.dump_mesonh()

After running the script, the directory should contains:

example/
├─ EXSEG1.nam
├─ FuelMap.des
├─ FuelMap.nc
├─ FuelMap2d.nc
├─ Init_file.des
├─ Init_file.nc
├─ simplecase.py

FuelMap2d.nc is an optional file that is easier for human to chack if the generated fuel map respects the requirements.

Create a fuel object

pyrolib contains several fuel objects that represent a fuel description as fuel properties. To show the list of available fuel object, use show_fuel_classes. The following example shows several methods to create a BalbiFuel object. Properties can be either modified in the constructor or set as default.

import pyrolib.fuels as pl

# print fuel classes available and default property values
pl.show_fuel_classes()

# create default fuel
fuel1 = pl.BalbiFuel()

# create default fuel and changes some properties
fuel2 = pl.BalbiFuel(e=2., Md=0.15)

# copy fuel2 and changes some properties
fuel3 = fuel2.copy(DeltaH=20e7, LAI=2)

# change property value after creation
fuel1.Ml.set(0.9)

Méso-NH compliance

The current version of pyrolib is compliant with Méso-NH from version 5.4.4 to version 5.5.0.

Acknowledgements

This library is part of the ANR FireCaster project (2017-2021, ANR-16-CE04-0006, FIRECASTER).