Accelerating the RTTOV-7 Radiative Transfer Model on Graphics Processing Units

摘要

We develop a Graphics Processing Unit (GPU)-based high-performance RTTOV-7 forward model. The RTTOV forward model performs the fast computation of the radiances, brightness temperatures, overcast radiances, surface to space transmittances, surface emissivities and pressure level to space transmittances for a given profile vector. A special optimized high performance CUDA kernel was used for multi-profile processing. The difference between single-profile and multi-profile kernels is that in a multi-profile kernel each thread is responsible for computing the results for a single channel in several profiles. Multi-profile processing gave over two fold increase in processing speed compared to single-profile processing. Using a GPU processing we reached promising speedups of 170x and 334x for single-profile and multi-profile processing, respectively. The significant 334x speedup means that the proposed GPU-based high-performance forward model is able to compute one day's amount of 1,296,000 Infrared Atmospheric Sounding Interferometer (IASI) spectra nearly within 12 minutes, whereas the original CPU-based version will impractically take nearly 3 days.