Some Climatological Aspects of the Madden–Julian Oscillation (MJO)Source: Journal of Climate:;2015:;volume( 028 ):;issue: 015::page 6039DOI: 10.1175/JCLI-D-14-00744.1Publisher: American Meteorological Society
Abstract: ne of the most commonly used metrics for both locating the Madden?Julian oscillation (MJO) geographically and defining the intensity of MJO convective activity is the real-time multivariate MJO (RMM) index. However, a climatology of the MJO, particularly with respect to the frequency of activity levels or of consecutive days at certain activity thresholds, does not yet exist. Thus, several climatological aspects of the MJO were developed in this study: 1) annual and 2) seasonal variability in MJO intensity, quantified using four defined activity categories (inactive, active, very active, and extremely active); 3) persistence in the above-defined four categories; 4) cycle length; and 5) low-frequency (decadal) variability.On an annual basis, MJO phases 1 and 2 occurred more often, and phase 8 occurred less often, than the other phases throughout the year. Notable seasonality was also found, particularly in the frequency of extremely active MJO in March?May (8% of days) compared with June?August (only 1% of days). The MJO was persistent in time and across intensity categories, and all activity categories the following day had at least an 80% chance of maintaining their amplitudes. Implications of this climatology are discussed, including length of complete MJO cycles (the shortest of which was 17 days) and correlations between MJO amplitude and atmospheric response.
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contributor author | Lafleur, Donald M. | |
contributor author | Barrett, Bradford S. | |
contributor author | Henderson, Gina R. | |
date accessioned | 2017-06-09T17:11:37Z | |
date available | 2017-06-09T17:11:37Z | |
date copyright | 2015/08/01 | |
date issued | 2015 | |
identifier issn | 0894-8755 | |
identifier other | ams-80884.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4223825 | |
description abstract | ne of the most commonly used metrics for both locating the Madden?Julian oscillation (MJO) geographically and defining the intensity of MJO convective activity is the real-time multivariate MJO (RMM) index. However, a climatology of the MJO, particularly with respect to the frequency of activity levels or of consecutive days at certain activity thresholds, does not yet exist. Thus, several climatological aspects of the MJO were developed in this study: 1) annual and 2) seasonal variability in MJO intensity, quantified using four defined activity categories (inactive, active, very active, and extremely active); 3) persistence in the above-defined four categories; 4) cycle length; and 5) low-frequency (decadal) variability.On an annual basis, MJO phases 1 and 2 occurred more often, and phase 8 occurred less often, than the other phases throughout the year. Notable seasonality was also found, particularly in the frequency of extremely active MJO in March?May (8% of days) compared with June?August (only 1% of days). The MJO was persistent in time and across intensity categories, and all activity categories the following day had at least an 80% chance of maintaining their amplitudes. Implications of this climatology are discussed, including length of complete MJO cycles (the shortest of which was 17 days) and correlations between MJO amplitude and atmospheric response. | |
publisher | American Meteorological Society | |
title | Some Climatological Aspects of the Madden–Julian Oscillation (MJO) | |
type | Journal Paper | |
journal volume | 28 | |
journal issue | 15 | |
journal title | Journal of Climate | |
identifier doi | 10.1175/JCLI-D-14-00744.1 | |
journal fristpage | 6039 | |
journal lastpage | 6053 | |
tree | Journal of Climate:;2015:;volume( 028 ):;issue: 015 | |
contenttype | Fulltext |