2021-01-21 All-Hands Presentation Meeting Notes

Presenter: Hui Wan

Title: Quantifying, attributing, and understanding time step sensitivities in the E3SMv1 atmosphere model.

Abstract:

Time integration error in physics parameterizations of global atmospheric models is an understudied topic. This presentation will discuss recent progress from a SciDAC project that aims at addressing this gap.

We will start by showing that the present-day climate simulated by version 1 of the E3SM atmosphere model, EAMv1, has non-negligible and inconvenient sensitivities to time step sizes. A series of numerical experiments have been carried out, the results from which provide useful information about which parameterizations or their interactions are the primary causes of time step sensitivities in different cloud regimes. We then zoom into the subtropical stratocumulus regions and reveal how the interplay between numerics and physics leads to a systematic decrease of cloud amount when model time steps are shortened, and discuss how EAM’s process coupling strategy can be revised to reduce the coupling error. These results deliver the important message that despite the complex interactions between nonlinear processes in the atmosphere, the sources of undesirable numerical artifacts can be identified and addressed. Some ongoing and planned work along that direction will also be briefly mentioned.

Date

21 Jan 2021

Time

PT: 8:30 am
ET: 11:30 am

Call Info

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Attendees

Presentation

Time

Title

Presenter

Presentation

Recording

Notes

30 min

Quantifying, attributing, and understanding time step sensitivities in the E3SMv1 atmosphere model

Hui Wan

HuiWan_20210121.pdf

MP4 Movie (on the E3SM YouTube Channel)