Implementation of 4DWX for ATEC Using a Dedicated Support Partition (DSP) and Advantages Over Using High-Priority Queues
The Four-Dimensional Weather System (4DWX), developed at the National Science Foundation
(NSF) National Center for Atmospheric Research (NCAR), is used by the US Army Test and
Evaluation Command (ATEC) to provide weather diagnostics and forecasts in real-time from
deterministic and probabilistic numerical weather prediction (NWP) models in support of the
outdoor testing at various Army Test Centers. 4DWX requires continuous cycling that is not
interrupted or delayed by batch processing, interactive processing, or any reservation
service. A numerical weather prediction system depends on complex coordination of many
interdependent processes, including processes that generate initial and boundary conditions
from global models and assimilate time-sensitive weather observations during early stages of
the system’s execution, and processes that operate on data and generate graphical products
during late stages. For continuous cycling in which the model’s spun-up state is drawn from a
prior simulated atmospheric state, each model cycle depends on the successful and timely
completion of the previous cycle.

Since 4DWX was ported to DoD HPC systems in 2017, it has used both Dedicated Support
Partitions (DSPs) and High Priority queues at different times. While the High Priority queues
have generally allowed for continuous cycling for 4DWX, resource contention does sometimes
occur due to other users submitting large numbers of jobs to the High Priority and Frontier
queues. This has resulted in model failures, delays, and down time for 4DWX. These problems
do not occur when using a DSP, which has demonstrated an exceptionally high level of
dependability for 4DWX. This talk will focus on an overview of the 4DWX system, the reliability
of the DSP in comparison to the High Priority queues, and how the demonstrated success of
DSP-backed 4DWX could serve as a model of expanding real-time, operational numerical
weather prediction support across multiple DoD domains in support of test and evaluation
requirements.
IMPACT
Provided detailed, high-resolution, atmospheric predictions to the Army Test and Evaluation Command (ATEC) that ensured the safety of test personnel and equipment while providing context for interpreting test results.
PRESENTER
Prestopnik, Paul
prestop@ucar.edu
720-278-4489
Mr.
CO-AUTHOR(S)
Shaw, Justin
jshaw@ucar.edu
Sheu, Rong-Shyang
sheu@ucar.edu
Soh, Howard
hsoh@ucar.edu
Halvorson, Scott
scott.f.halvorson.civ@army.mil
CATEGORY
Weather &  Ocean Modeling & Sim
SYSTEM(S) USED
Nautilus, Ruth, and Narwhal