Optimization of the parallel semi-Lagrangian scheme in the YHGSM based on the adaptive maximum wind speed

EasyChair Preprint 5947

Abstract

The Yin-He global spectral model (YHGSM), developed by the National University of Defense Technology, embodies a parallel semi-Lagrangian solver and has two schemes implemented: maximum wind speed and on-demand communication. The communication in the maximum wind speed uses a single, fixed data structure with a global maximum wind speed; although straightforward to implement, it incurs a high communication overhead. In contrast, the on-demand communication scheme only uses the maximum wind scheme for the wind field to calculate the trajectory. Subsequently, only necessary data are communicated for the interpolation of the other fields, which reduces the communication overhead. In this paper, a novel adaptable approach is proposed in which a monthly maximum wind speed is used in the YHGSM. The candidate monthly maximum wind speeds are extracted from the ERA-interim wind data from 2001 to 2018; the value selected corresponds to the initial date of the forecast. This approach reduces the difference between the actual wind speed and the maximum wind speed used in the model; in turn, the communication overhead in the trajectory computation is further reduced. Experiments show that in the maximum wind and on-demand schemes, the communication overheads with the adaptive maximum wind speed are significantly reduced. In addition, in a ten-day forecast with the on-demand communication scheme, the total overhead for the semi-Lagrangian computing and the total parallel execution time are also both reduced, and the reduction ratio increases as the number of nodes increases.

Keyphrases: communication overhead, maximum wind speed, numerical weather prediction, parallel Semi-Lagrangian scheme

@booklet{EasyChair:5947,
  author    = {Dazheng Liu and Jianping Wu and Tao Jiang and Yingjie Wang and Xiaotian Pan and Penglun Li},
  title     = {Optimization of the parallel semi-Lagrangian scheme in the YHGSM based on the adaptive maximum wind speed},
  howpublished = {EasyChair Preprint 5947},
  year      = {EasyChair, 2021}}