Climate modeling with Fortran

A deep dive into high-resolution atmospheric simulations using Fortran's array optimization capabilities.

August 13, 2025

Introduction to Climate Modeling

Climate modeling represents one of the most computationally demanding scientific challenges. With Fortran's array-centric design and compiler-driven vectorization, we see extraordinary performance gains in creating detailed climate simulations.

Fortran's Role in Climate Science

Modern climate models use millions of mesh points to simulate ocean and atmospheric flow. Fortran's ability to parallelize and optimize array expressions makes it ideal for weather prediction models.

📦 Fortran 2018 Climate Code


module climate_model
    implicit none
    integer, parameter :: Nx = 128, Ny = 128, Nz = 64
    real(kind=8), dimension(Nx,Ny,Nz) :: pressure, temperature, moisture
    real(kind=8), dimension(:,:,:), allocatable :: wind_velocity

contains

    subroutine update_pressure(new_press, time)
        real(kind=8), intent(out) :: new_press(Nx,Ny,Nz)
        real(kind=8), intent(in) :: time

        new_press = 0.0
        !\$omp parallel do
        do k = 1, Nz
            do j = 1, Ny
                do i = 1, Nx
                    new_press(i,j,n) = pressure(i,j,n) * exp(-time * temperature(i,j,n)/moisture(i,j,n))
                end do
            end do
        end do
    end subroutine update_pressure
end module climate_model

                        
512 cores
98% utilized

Parallel performance of Fortran-based atmospheric simulation across 512 cores

Summary

Fortran's strength in scientific computing continues to deliver unparalleled performance in climate science. With Fortran 2018 standards and enhanced support for multidimensional parallelism, it's a prime platform for next-generation climate prediction.