The BVE (Barotropic Vorticity Equation) is the topic of chapter 5 of the book. The numerical implementation of the BVE on the sphere (radius a) by the spectral method forms a standard NWP model widely used in numerical modeling in the atmospheric sciences. Such a spectral implementation of the BVE is part of PEAK (in its barotropic configuration - see chapter 12). An alternative (somewhat more concise) BVE implementation derived from the full PEAK code is made available below, as file:
pk_code_s8b.f90
When executed this code produces the xx41 file as follows:
xx41_b_bm
file history: the above two files pulled from Documents/peak_2009 (26 August 2011)
This code is set to integrate the Rossby-Haurwitz-wave initial condition of sec. 12.2.3 over a time period of 28 x 600 seconds. This code is not discussed in detail in the book (see, however, sec. 7.14 on p. 245) and should be understood as a prototypical spectral BVE implementation to serve for further adaption as needed.
As the structure of this BVE code is fully analogous to the full PEAK code, with, however, vertical complexities absent, this BVE code is ideally suited for studying the basic spectral framework of PEAK, and, in particular, the technicalities of the transform method.
This (one-level, of course) barotropic PEAK version implementing the BVE spectrally on the sphere requires precisely the same library files as the full baroclinic PEAK code, namely aux_routines_v2.f90 and nr_routines_v1.f90 [see→ copyright] as described on the Code page.
Sunday, 03 March 2024