Quantifying the Effect of Climate Change on Midlatitude Subseasonal Prediction Skill Provided by the Tropics

Journal Article · 14 July 2022 · Geophysical Research Letters

DOI: https://doi.org/10.1029/2022GL098663 · OSTI ID:1876216

Mayer, Kirsten J.  ^[1]; Barnes, Elizabeth A.  ^[1]

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1. Department of Atmospheric Science Colorado State University Fort Collins CO USA

Abstract Subseasonal timescales (∼2 weeks–2 months) are known for their lack of predictability, however, specific Earth system states known to have a strong influence on these timescales can be harnessed to improve prediction skill (known as “forecasts of opportunity”). As the climate continues warming, it is hypothesized these states may change and consequently, their importance for subseasonal prediction may also be impacted. Here, we examine changes to midlatitude subseasonal prediction skill provided by the tropics under anthropogenic warming using artificial neural networks to quantify skill. The network is tasked to predict the sign of the 500 hPa geopotential height for historical and future time periods in the Community Earth System Model Version 2 ‐ Large Ensemble across the Northern Hemisphere at a 3 week lead using tropical precipitation. We show prediction skill changes substantially in key midlatitude regions and these changes appear linked to changes in seasonal variability with the largest differences in accuracy occurring during forecasts of opportunity.

• Sponsoring Organization: USDOE
• OSTI ID: 1876216
• Journal Information: Geophysical Research Letters, Journal Name: Geophysical Research Letters Journal Issue: 14 Vol. 49; ISSN 0094-8276
• Publisher: American Geophysical Union (AGU)Copyright Statement
• Country of Publication: United States
• Language: English