Details

Autor(en) / Beteiligte

• Ordaz Osorio, C.
• Booth, J. F.
• LeGrande, A. N.
• Naud, C. M.

Titel

Assessing the Impact of Climate Change on Atmospheric Rivers: A Modeling Perspective

Ist Teil von

• Journal of geophysical research. Atmospheres, 2024-06, Vol.129 (12), p.n/a

Ort / Verlag

Washington: Blackwell Publishing Ltd

Erscheinungsjahr

2024

Link zum Volltext

Quelle

Wiley Online Library

Beschreibungen/Notizen

• Atmospheric rivers (ARs) play a crucial role in the poleward transport of water vapor, and the AR‐associated precipitation is a critical component of global water supplies, making it critical that we understand how ARs may change in the future. To approach this issue, integrations of the NASA Goddard Institute for Space Studies global climate model ModelE version 2.1 (GISSE2.1) are employed. Multiple configurations of the model simulating different climates are analyzed: (a) the last‐glacial maximum; (b) present day; (c) the end of the 21st century. The thermodynamic and dynamic components of changes to AR frequency are analyzed using a decomposition method. This method utilizes differences in distinct AR seasonal climatology frequencies derived from various vertically integrated water vapor transport (IVT) thresholds to resolve AR frequency into its components. Global mean state changes in poleward AR frequency for different climates are dominated by precipitable water vapor (PWV) changes. A set of idealized cold and warm climates in which present day sea surface temperatures are uniformly changed are considered for a targeted analysis of the south Pacific Ocean basin. For this analysis, frequency and distribution of AR events in the model runs are analyzed by comparing them to changes in the jet stream as well as the Eulerian storm tracks and low‐level baroclinicity. Latitudinal shifts in the ARs in the south Pacific Ocean basin using our integrations are not as tightly coupled to these two storm‐related climatological metrics in the midlatitudes but fare better on the poleward side of the storm tracks. Plain Language Summary ARs are important for transporting water vapor and supplying precipitation in various regions around the globe. Understanding how ARs may change in the future is crucial for managing water resources. We use a global climate model to simulate different climate conditions: the last‐glacial maximum, present day, and the end of the 21st century. A method to identify the temperature related and circulation contributors to changes in AR frequency is introduced. This method compares AR frequencies produced using different thresholds to identify ARs. Changes in how often ARs happen are controlled by changes in temperature throughout different climate states. A set of idealized cold and warm climates are examined over the south Pacific Ocean basin by adjusting sea surface temperatures. ARs in the south Pacific Ocean are studied via their frequency and distribution in different climate scenarios. Latitudinal shifts of ARs are not closely linked to changes in the jet stream or storm activity as anticipated in the midlatitude regions of the south Pacific Ocean basin, but do better closer to the south pole. These findings contribute to our understanding of how ARs may respond to climate change and highlight the complex interactions between atmospheric dynamics and AR behavior. Key Points For distinct climates, changes in PWV dominate the changes in thresholds defining ARs with dynamic changes being secondary In the South Pacific, AR frequency changes match changes in dynamical metrics better on the poleward side of the midlatitudes In the South Pacific, AR changes in different climates often match with changes in the 250 hPa jet better than changes in storm tracks