Influence of Madden-Julian Oscillation on water budget transported by the Somali low-level jet and the associated Indian summer monsoon rainfall

Abstract

[1] Recent studies suggest that there is a strong linkage between the moisture uptake over the equatorial area of the Somali low level jet (SLLJ) and the rainfall variability over most of continental India. Additionally, the Madden-Julian Oscillation (MJO) strongly modulates the intraseasonal variability of the Indian summer monsoon rainfall, since the northward propagation of the boreal summer MJO is closely associated with the active and break phases of monsoon rainfall. But a question remains open: is there a relationship between the moisture transported by the SLLJ and the MJO evolution? In this paper, a Lagrangian approach is used to track the evaporation minus precipitation (E À P) evolution along trajectories of particles initially situated over the equatorial region of SLLJ. The impact of the MJO on the water budget transport of the SLLJ is examined by making composites of the obtained (E-P) fields for the different MJO phases. The spatial structures of the boreal summer intraseasonal oscillation are revealed in our results, which strongly suggest that the main responsible for the rainfall variability associated to the MJO in these regions are the changes in the moisture advected by the SLLJ. In order to assess the MJO-SLLJ interaction, an analysis of the total-column mass and the total-column specific humidity transported by the SLLJ during the MJO life cycle is performed. While a systematic difference between air mass advected to India during active and break phases of MJO is not detected, changes in the moisture of particles are found, with wet (dry) anomalies over enhanced (suppressed) convection region. This result implicitly leads to assume air-sea interaction processes.Citation: Ordonez, P., P. Ribera, D. Gallego, and C. Pena-Ortiz (2013), Influence of Madden-Julian Oscillation on water budget transported by the Somali low-level jet and the associated Indian summer monsoon rainfall, Water Resour. Res., 49,[6474][6475][6476][6477][6478][6479][6480][6481][6482][6483][6484][6485]

An apparent relationship between Madden–Julian Oscillation and the advance of Indian summer monsoon

“…Inter‐annual variation is observed in advance‐period of ISM and intra‐seasonal variations are the major contributing factors for variation in the advance period of ISM. Ordoñez et al () have shown the water transported by the Somali low level jet (SLLJ) towards India in terms of the both air mass advected and changes in its moisture content as a function of the MJO phase. Birch et al () have shown the difference between rainfall over land and rainfall over Ocean caused by particular MJO phase.…”

The modulation of oceanic moisture transport by the hemispheric annular modes

“…These regions are more influenced by the evolution of the El Niño-Southern Oscillation as described by Castillo et al (2014), who found that during winter El Niño events, the ZAN and ARAB sources increase their moisture contribution in the western Indian Ocean. Additionally, these sources are crossed by the Somali Jet, which is the main supply of moisture during the Indian Summer Monsoon, and is strongly modulated by the Madden-Julian Oscillation (Ordóñez et al, 2013).…”

Role of Oceanic and Terrestrial Atmospheric Moisture Sources in Intraseasonal Variability of Indian Summer Monsoon Rainfall

“…This further underscores the need for further understanding the active and break cycles and prediction of their characteristics for adaptation of agriculture and water management to climate variability and change 25 , especially considering the inadequacies of the current climate models 26 , 27 . The lack of skill is partly attributable to inadequate understanding of synoptic scale processes such as the Monsoon Intra Seasonal Oscillation ( MISO) 27 , 28 , Madden Julian Oscillation (MJO) 29 – 32 , migration of the Inter-Tropical Convergence Zone (ITCZ) 1 , 9 to the northern latitudes, convection over the Bay of Bengal 33 , interactions of ISMR with aerosols through direct radiative forcing 34 , and the atmospheric moisture transport 35 to the Indian subcontinent. Understanding of the moisture source availability and its variability will advance our understanding of all these related processes.…”