Work

Local Finite‐Amplitude Wave Activity of Water Vapor as a Diagnostic of Atmospheric River Events

Year: 2025

Type: article

Abstract: We generalize the formalism of local wave activity of quasi‐geostrophic potential vorticity to water vapor, defined as LWA‐V, and derive the LWA‐V budget equation. LWA‐V measures the waviness of moisture contours from the zonal symmetry in the eddy‐free atmosphere. It delineates well the northward moisture intrusion and the filamentary feature of AR events. Compared with the traditional moisture budget, the climatological LWA‐V and LWA‐V budget terms are more consistent in structure and are able to delineate the climatological AR. Moisture flux convergence is the dominant process for the intensification and movement of the LWA‐V center associated with the AR event while the combined effect of evaporation and precipitation is mainly a sink of LWA‐V, which is consistent with traditional moisture budget analysis. Furthermore, utilizing the Lagrangian aspect of LWA‐V, we demonstrate quantitatively that the original latitudes of the largest precipitable water of the AR event are in the tropical region.

Source: Geophysical Research Letters

DOI: 10.1029/2024gl114314

Authors: Rui Zhang, Edmund K. M. Chang

Institution: Stony Brook University

Language: English

Topic: Meteorological Phenomena and Simulations

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,190