Weather systems associated with synoptic variability in the moist margin

Abstract

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 (LPSs), and extratropical interactions with the moist margin characterised by upper-level potential vorticity (PV) anomalies. We use an object-based approach in which, first, objects are defined to describe the variability of the moist margin a..