Robin Hogan [email protected]

This document was last updated 10 October 2020

This package contains the offline version of a scheme for computing radiative transfer in complex 3D surface canopies, such as forests and cities. It makes use of the "SPARTACUS" technique, originally developed for clouds. By treating trees and buildings as randomly distributed in the horizontal plane, their 3D structure may be described statistically by a handful of geometric properties, such as the tree or building cover, and the length of the interface between tree crowns or building walls and clear air. See Hogan et al. (2018) and Hogan (2019) for full details of the algorithm, and their validation.

The subdirectories are as follows:

• radsurf - source code for radiative transfer in complex surfaces such as vegetation and urban areas

• radtool - source code for mathematical routines needed by the SPARTACUS algorithm

• utilities - source code for useful utilities, such as reading netCDF files

• driver - the source code for the offline driver program

• mod - where Fortran module files are written

• lib - where the static libraries are written

• bin - where the executable ecrad is written

• test - test cases including Matlab code to plot the outputs

• doc - LaTeX source for SPARTACUS-Surface documentation

1. Ensure you have a Fortran compiler supporting the 2003 standard. Ensure you have the Fortran netCDF library installed (version 3 or 4) for this compiler. The command nc-config --fc, if available on your system, will tell you the Fortran compiler that your netCDF library was compiled for.

2. You can compile the code using

   make PROFILE=<prof>
   

   where <prof> is one of gfortran, pgi or intel. This will read the compiler-specific configurations from the file Makefile_include.<prof>. If you omit the PROFILE= option then gfortran will be assumed. If you have a compiler other than these three then create such a file for your compiler following the example in Makefile_include.gfortran.

   If the compile is successful then static libraries should appear in the lib directory, and then the executable bin/spartacus_surface.

3. To clean-up, type make clean. To build an unoptimized version for debugging, you can do

   make PROFILE=<prof> DEBUG=1
   

   or you can specifically override the variables in Makefile_include.<prof> using, for example

   make PROFILE=<prof> OPTFLAGS=-O0 DEBUGFLAGS="-g -pg"
   

The offline driver is run via

spartacus_surface <namelist.nam> <input_file.nc> <output_file.nc>

where the radiation scheme is configured using the Fortran namelist file <namelist.nam>, and the inputs and outputs are in netCDF format.

To run the tests, type

make test

from the top-level directory. This runs make in each of the subdirectories of the test directory, which in turn runs spartacus_surface on different input files.

The test/simple directory contains a minimal test file of the four surface types that SPARTACUS-Surface supports: flat, forest, unvegetated urban and vegetated urban.

The test/rami4pilps directory contains a configuration to run the RAMI4PILPS test cases that were used by Hogan et al. (2018).

The test/urban directory contains an urban profile from Fig. 1 of Hogan (2019).

(C) Copyright 2019- ECMWF.

This software is licensed under the terms of the Apache Licence Version 2.0 which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.

In applying this licence, ECMWF does not waive the privileges and immunities granted to it by virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction. Copyright statements are given in the file NOTICE.

Hogan, R. J., T. Quaife and R. Braghiere, 2018: Fast matrix treatment of 3-D radiative transfer in vegetation canopies: SPARTACUS-Vegetation 1.1. Geosci. Model Dev., 11, 339-350.

Hogan, R. J., 2019: Flexible treatment of radiative transfer in complex urban canopies for use in weather and climate models. Boundary-Layer Meteorol., 173, 53-78.

Please email Robin Hogan [email protected] with any queries or bug fixes, but note that ECMWF does not commit to providing support to users of this software.