Near‐global impact of the Madden‐Julian Oscillation on rainfall

Abstract

[1] The accuracy of synoptic-based weather forecasting deteriorates rapidly after five days and is not routinely available beyond 10 days. Conversely, climate forecasts are generally not feasible for periods of less than 3 months, resulting in a weather-climate gap. The tropical atmospheric phenomenon known as the Madden-Julian Oscillation (MJO) has a return interval of 30 to 80 days that might partly fill this gap. Our near-global analysis demonstrates that the MJO is a significant phenomenon that can influence daily rainfall patterns, even at higher latitudes, via teleconnections with broadscale mean sea level pressure (MSLP) patterns. These weather states provide a mechanistic basis for an MJO-based forecasting capacity that bridges the weather-climate divide. Knowledge of these tropical and extra-tropical MJOassociated weather states can significantly improve the tactical management of climate-sensitive systems such as agriculture. Citation: Donald, A

The autumn break for cropping in southeast Australia: trends, synoptic influences and impacts on wheat yield

“…Individual rainfall events over southern Australia also appear to be influenced on the intraseasonal time-scale by the Madden-Julian Oscillation (MJO), a large-scale eastward propagating wave in the tropical atmosphere which produces periods of enhanced and diminished convection as it migrates across the Indian and Pacific Oceans (Donald et al, 2006). The MJO can be classified into eight phases based on the leading patterns of variability of the zonal wind in the near-equatorial latitudes (Wheeler and Hendon, 2004).…”

Seasonal climate summary southern hemisphere (spring 2012): warmer and drier across much of Australia, along with a new southern hemisphere sea ice extend record

“…An active MJO is characterised by an eastward-propagating atmospheric anomaly near the equator that typically recurs every 30 to 60 days. It can often be detected by areas of strong negative equatorial OLR anomalies (a proxy for enhanced convective activity) that develop in the Indian Ocean and propagate eastward into the Pacific Ocean (Zhang 2005, Donald et al 2006 OLR values across the Indian and Pacific oceans for spring 2012 are displayed in Fig. 3.…”

The Madden-Julian Oscillation: A Tool for Regional Seasonal Precipitation Outlooks?

“…While other studies have noted a near-global impact of the MJO on rainfall [6], this is the first to quantify the relationship using field significance and compare it to ENSO, which is an already established predictor of seasonal rainfall at the global scale. It appears that the phase of the MJO is very important in determining its value as a predictor of seasonal rainfall.…”

“…A popular index of the MJO was created and divided into eight phases [4] to account for its changing geography. The distribution of rainfall and extreme events has been found to undergo significant changes over many areas of the world during active and quiescent phases of the MJO [5,6]. However, sometimes it is the accumulated effect of the MJO over a season that is more important for climate teleconnections.…”

“…The study focuses on societal impacts by investigating extratropical seasonal precipitation anomalies over land. As stated by Donald et al [6] (p. 1), "Knowledge of these tropical and extra-tropical MJO-associated weather states can significantly improve the tactical management of climate-sensitive systems such as agriculture." Finally, the El Niño/Southern Oscillation (ENSO) is a primary predictor in seasonal climate outlooks.…”