Abstract
Abstract. An interpolation programme coded in Fortran for irregular N-dimensional cases is presented and freely available. The need for interpolation procedures over irregular meshes or matrixes with interdependent input data dimensions is frequent in geophysical models. Also, these models often embed look-up tables of physics or chemistry modules. Fortran is a fast and powerful language and is highly portable. It is easy to interface models written in Fortran with each other. Our programme does not need any libraries; it is written in standard Fortran and tested with two usual compilers. The programme is fast and competitive compared to current Python libraries. A normalization option parameter is provided when considering different types of units on each dimension. Some tests and examples are provided and available in the code package. Moreover, a geophysical application embedding this interpolation programme is provided and discussed; it consists in determining back trajectories using chemistry-transport or mesoscale meteorological model outputs, respectively, from the widely used CHIMERE and Weather Research and Forecasting (WRF) models.
Highlights
Interpolation is commonly used in geophysical sciences for post-treatment processing to evaluate model performance against ground station observations
Fortran is extensively used for atmosphere modelling software (Sun and Grimmond, 2019; e.g. the Weather Research and Forecasting model – WRF, Skamarock et al, 2008; the Geophysical Fluid Dynamics Laboratory atmospheric component version 3 – GFDL AM3, Donner et al, 2011)
Geophysical models can use look-up tables of complex modules instead of a full coupling strategy between these modules, which is the case of the CHIMERE model (Mailler et al, 2017) with the embedded ISORROPIA module dealing with chemistry and thermodynamics (Nenes et al, 1998, 1999)
Summary
Interpolation is commonly used in geophysical sciences for post-treatment processing to evaluate model performance against ground station observations. The goal of this paper is to present a programme to interpolate in a grid or a matrix which can be irregular (varying intervals) but structured, with the possibility to have interdependent dimensions (e.g. longitude interval edges which depend on longitude, latitude, altitude and time). We think this type of programme can be implemented within models or to manage model outputs for posttreatment issues. In order to quantify the impact of such a new interpolation programme and show examples of its use, it is implemented in the Backplumes back-trajectory model, developed by the same team as the CHIMERE model (Mailler et al, 2017). These two codes are freely available (see code availability section)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
