Preprints
https://doi.org/10.5194/egusphere-2023-2165
https://doi.org/10.5194/egusphere-2023-2165
15 Jan 2024
 | 15 Jan 2024

An Extensible Perturbed Parameter Ensemble (PPE) for the Community Atmosphere Model Version 6

Trude Eidhammer, Andrew Gettelman, Katherine Thayer-Calder, Duncan Watson-Parris, Gregory Elsaesser, Hugh Morrison, Marcus van Lier-Walqui, Ci Song, and Daniel McCoy

Abstract. This paper documents the methodology and preliminary results from a Perturbed Parameter Ensemble (PPE) technique, where multiple parameters are varied simultaneously and the parameter values are determined with Latin hypercube sampling. This is done with the Community Atmosphere Model version 6 (CAM6), the atmospheric component of the Community Earth System Model version 2 (CESM2). We apply the PPE method to CESM2-CAM6 to understand climate sensitivity to atmospheric physics parameters. The initial simulations vary 45 parameters in the microphysics, convection, turbulence and aerosol schemes with 263 ensemble members. These atmospheric parameters are typically the most uncertain in many climate models. Control simulations are analyzed and targeted simulations to understand climate forcing due to aerosols and fast climate feedbacks. The use of various emulators is explored in the multi- dimensional space mapping input parameters to output metrics. Parameter impacts on various model outputs, such as radiation, cloud and aerosol properties are evaluated. Machine learning is also used to probe optimal parameter values against observations. Our findings show that using PPE is a valuable tool for climate uncertainty analysis. Furthermore, by varying many parameters simultaneously, we find that many different combinations of parameter values can produce results consistent with observations, and thus careful analysis of tuning is important. The CESM2-CAM6 PPE is publicly available, and extensible to other configurations to address questions of other model processes in the atmosphere and other model components (e.g. coupling to the land surface).

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Trude Eidhammer, Andrew Gettelman, Katherine Thayer-Calder, Duncan Watson-Parris, Gregory Elsaesser, Hugh Morrison, Marcus van Lier-Walqui, Ci Song, and Daniel McCoy

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-2165', Anonymous Referee #1, 12 Feb 2024
  • CC1: 'Comment on egusphere-2023-2165', Pappu Paul, 30 Apr 2024
    • AC1: 'Reply on CC1', Trude Eidhammer, 06 May 2024
      • CC2: 'Reply on AC1', Pappu Paul, 06 May 2024
  • RC2: 'Comment on egusphere-2023-2165', Anonymous Referee #2, 23 May 2024
Trude Eidhammer, Andrew Gettelman, Katherine Thayer-Calder, Duncan Watson-Parris, Gregory Elsaesser, Hugh Morrison, Marcus van Lier-Walqui, Ci Song, and Daniel McCoy

Data sets

CESM2.2-CAM6 Perturbed Parameter Ensemble (PPE) Trude Eidhammer, Andrew Gettelman, and Katherine Thayer-Calder https://doi.org/10.26024/bzne-yf09

CERES_EBAF_Ed4.1_2001-2020 subset Trude Eidhammer and Andrew Gettelman https://zenodo.org/records/10426438

Trude Eidhammer, Andrew Gettelman, Katherine Thayer-Calder, Duncan Watson-Parris, Gregory Elsaesser, Hugh Morrison, Marcus van Lier-Walqui, Ci Song, and Daniel McCoy

Viewed

Total article views: 720 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
445 250 25 720 21 20
  • HTML: 445
  • PDF: 250
  • XML: 25
  • Total: 720
  • BibTeX: 21
  • EndNote: 20
Views and downloads (calculated since 15 Jan 2024)
Cumulative views and downloads (calculated since 15 Jan 2024)

Viewed (geographical distribution)

Total article views: 737 (including HTML, PDF, and XML) Thereof 737 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 20 Jun 2024
Download
Short summary
We describe a dataset where 45 parameters related to cloud processes in the Community Earth System Model v2 (CESM2) Community Atmosphere Model v6 (CAM6) are perturbed. Three sets of perturbed parameter ensembles (263 members) were created; current climate, pre-industrial aerosol loading and future climate with sea surface temperature increased by 4-degree K.