Loading [MathJax]/jax/output/HTML-CSS/fonts/TeX/fontdata.js
Preprints
https://doi.org/10.5194/egusphere-2024-3150
https://doi.org/10.5194/egusphere-2024-3150
21 Oct 2024
 | 21 Oct 2024

Weather systems associated with synoptic variability in the moist margin

Corey Michael Robinson, Sugata Narsey, Christian Jakob, and Hanh Nguyen

Abstract. The moist margin is a sharp gradient of humidity that separates the moist deep tropics from the drier subtropics, and its movement is known to have an important effect on rainfall variability. In this work, we investigate how weather systems are related to synoptic variability in the moist margin. The weather systems considered include convectively coupled equatorial waves and the Madden-Julian Oscillation (MJO), monsoon low-pressure systems (LPS), and extratropical interactions with the moist margin characterised by upper-level potential vorticity (PV). We use an object-based approach in which first, objects are defined to describe the variability of the moist margin, and then are related to weather objects representing the above weather systems. Overall, the results indicate that these weather systems are associated with a large proportion of variability in the moist margin. The MJO and equatorial Rossby wave have a significant modulating effect on the moist margin. In comparison, monsoon LPS are infrequent but strongly influence the moist margin when they occur. Interactions with the extratropics occur for around one quarter of moist margin perturbations, and display a clear wave-like signal, often with anticyclonic PV anomalies near the perturbed margin and cyclonic PV anomalies remotely. Overall, objects associated with weather systems are larger, longer-lived, and precipitate more, highlighting the important role of weather systems.

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.
Share
Download
Short summary
Rainfall in the tropics is strongly related to the amount of moisture in the atmosphere. In this...
Share