Impacts of intraseasonal oscillation on the onset and interannual variation of the Indian summer monsoon

Abstract The possibility of using remote sensing retrievals to estimate apparent water vapor sinks and heat sources is explored. The apparent water vapor sinks and heat sources are estimated from a combination of remote sensing, specific humidity, and temperature from the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit (AIRS) and wind fields from the National Aeronautics and Space Administration (NASA)’s Goddard Space Flight Center (GSFC)’s Modern Era Retrospective-Analysis for Research and Applications (MERRA). The intraseasonal oscillation (ISO) of the Indian summer monsoon is used as a test bed to evaluate the apparent water vapor sink and heat source. The ISO-related northward movement of the column-integrated apparent water vapor sink matches that of precipitation observed by the Tropical Rainfall Measuring Mission (TRMM) minus the MERRA surface evaporation, although the amplitude of the variation is underestimated by 50%. The diagnosed water vapor and heat budgets associated with convective events during various phases of the ISO agree with the moisture–convection feedback mechanism. The apparent heat source moves northward coherently with the apparent water vapor sink associated with the deep convective activity, which is consistent with the northward migration of the precipitation anomaly. The horizontal advection of water vapor and dynamical warming are strong north of the convective area, causing the northward movement of the convection by the destabilization of the atmosphere. The spatial distribution of the apparent heat source anomalies associated with different phases of the ISO is consistent with that of the diabatic heating anomalies from the trained heating (TRAIN Q1) dataset. Further diagnostics of the TRAIN Q1 heating anomalies indicate that the ISO in the apparent heat source is dominated by a variation in latent heating associated with the precipitation.

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The Intraseasonal Fluctuation of Indian Summer Monsoon Rainfall and its Relation with Monsoon Intraseasonal Oscillation (MISO) and Madden Julian Oscillation (MJO)

10.21203/rs.3.rs-432059/v1 ◽

2021 ◽

Author(s):

Avijit Dey ◽

R. Chattopadhyay ◽

S. Joseph ◽

M. Kaur ◽

R. Mandal ◽

...

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

Monsoon Rainfall ◽

Indian Summer Monsoon Rainfall ◽

Intraseasonal Oscillation ◽

Summer Monsoon Rainfall ◽

Madden Julian Oscillation ◽

Phase 2 ◽

Seasonal Fluctuations ◽

Northward Propagation

Abstract The intra-seasonal fluctuations of Indian summer monsoon rainfall (ISMR) are mainly controlled by northward propagating Monsoon Intra-seasonal Oscillation (MISO) and eastward propagating Madden Julian Oscillation (MJO). In the current study, we examine the relationship between the intra-seasonal fluctuations (active and break spells) of ISMR with the phase propagation and amplitude of MISO and MJO. We notice that active spells generally occur during MISO phase 2–5 (MJO phase 3–6), and break spells mainly occur during MISO phase 6–8 (MJO phase 6–8 and 1). The association of active/break spells with MISO phases is more prominent than with MJO phases. We show the phase composite of unfiltered and regression based reconstructed rainfall for eight MISO and MJO phases, and the same is consistent with the earlier findings. We notice that the reconstructed field shows a systematic and well-organised northward propagation compared to the unfiltered field. Phase composite also indicates that there is a lead-lag relationship between MISO and MJO phases. MISO phase composite shows more robust northward propagation than the MJO phase composite. MISO reconstructed rainfall explained more percentage variance than MJO reconstructed rainfall with reference to 20–90 days filtered rainfall. It is found that long active (> 7 days) predominantly occurs when either MISO or MJO, or both of them are active, and the associated signal is somewhere in between phase 2–5. A long break occurs when either one or both of them are feeble, or even though associated signals are strong, they are primarily located in phases 1, 6, 7 and 8.

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Intraseasonal Oscillation of Tropospheric Ozone over the Indian Summer Monsoon Region

Advances in Atmospheric Sciences ◽

10.1007/s00376-018-8113-7 ◽

2019 ◽

Vol 36 (4) ◽

pp. 417-430

Author(s):

Yuli Zhang ◽

Chuanxi Liu ◽

Yi Liu ◽

Rui Yang

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

Tropospheric Ozone ◽

Intraseasonal Oscillation ◽

Monsoon Region ◽

Summer Monsoon Region

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Tropical and mid-latitude teleconnections interacting with the Indian summer monsoon rainfall: a theory-guided causal effect network approach

Earth System Dynamics ◽

10.5194/esd-11-17-2020 ◽

2020 ◽

Vol 11 (1) ◽

pp. 17-34 ◽

Cited By ~ 2

Author(s):

Giorgia Di Capua ◽

Marlene Kretschmer ◽

Reik V. Donner ◽

Bart van den Hurk ◽

Ramesh Vellore ◽

...

Keyword(s):

Standard Deviation ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Causal Effect ◽

Intraseasonal Variability ◽

Intraseasonal Oscillation ◽

Causal Link ◽

Teleconnection Pattern ◽

Boreal Summer ◽

Circumglobal Teleconnection

Abstract. The alternation of active and break phases in Indian summer monsoon (ISM) rainfall at intraseasonal timescales characterizes each ISM season. Both tropical and mid-latitude drivers influence this intraseasonal ISM variability. The circumglobal teleconnection observed in boreal summer drives intraseasonal variability across the mid-latitudes, and a two-way interaction between the ISM and the circumglobal teleconnection pattern has been hypothesized. We use causal discovery algorithms to test the ISM circumglobal teleconnection hypothesis in a causal framework. A robust causal link from the circumglobal teleconnection pattern and the North Atlantic region to ISM rainfall is identified, and we estimate the normalized causal effect (CE) of this link to be about 0.2 (a 1 standard deviation shift in the circumglobal teleconnection causes a 0.2 standard deviation shift in the ISM rainfall 1 week later). The ISM rainfall feeds back on the circumglobal teleconnection pattern, however weakly. Moreover, we identify a negative feedback between strong updraft located over India and the Bay of Bengal and the ISM rainfall acting at a biweekly timescale, with enhanced ISM rainfall following strong updraft by 1 week. This mechanism is possibly related to the boreal summer intraseasonal oscillation. The updraft has the strongest CE of 0.5, while the Madden–Julian oscillation variability has a CE of 0.2–0.3. Our results show that most of the ISM variability on weekly timescales comes from these tropical drivers, though the mid-latitude teleconnection also exerts a substantial influence. Identifying these local and remote drivers paves the way for improved subseasonal forecasts.

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Evaluation of NCEP TIGGE short-range forecast for Indian summer monsoon intraseasonal oscillation

Theoretical and Applied Climatology ◽

10.1007/s00704-016-1811-0 ◽

2016 ◽

Vol 129 (3-4) ◽

pp. 745-782

Author(s):

Snehlata Tirkey ◽

P. Mukhopadhyay

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

Short Range ◽

Intraseasonal Oscillation

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Prediction of Indian Summer Monsoon Onset Using Dynamical Subseasonal Forecasts: Effects of Realistic Initialization of the Atmosphere

Monthly Weather Review ◽

10.1175/mwr-d-14-00187.1 ◽

2015 ◽

Vol 143 (3) ◽

pp. 778-793 ◽

Cited By ~ 19

Author(s):

Andrea Alessandri ◽

Andrea Borrelli ◽

Annalisa Cherchi ◽

Stefano Materia ◽

Antonio Navarra ◽

...

Keyword(s):

Summer Monsoon ◽

Indian Summer Monsoon ◽

General Circulation ◽

Large Scale ◽

Initial Conditions ◽

Intraseasonal Oscillation ◽

Circulation Model ◽

Tropical Indian Ocean ◽

Monsoon Onset ◽

Mean State

Abstract Ensembles of retrospective 2-month dynamical forecasts initiated on 1 May are used to predict the onset of the Indian summer monsoon (ISM) for the period 1989–2005. The subseasonal predictions (SSPs) are based on a coupled general circulation model and recently they have been upgraded by the realistic initialization of the atmosphere with initial conditions taken from reanalysis. Two objective large-scale methods based on dynamical-circulation and hydrological indices are applied to detect the ISM onset. The SSPs show some skill in forecasting earlier-than-normal ISM onsets, while they have difficulty in predicting late onsets. It is shown that significant contribution to the skill in forecasting early ISM onsets comes from the newly developed initialization of the atmosphere from reanalysis. On one hand, atmospheric initialization produces a better representation of the atmospheric mean state in the initial conditions, leading to a systematically improved monsoon onset sequence. On the other hand, the initialization of the atmosphere allows some skill in forecasting the northward-propagating intraseasonal wind and precipitation anomalies over the tropical Indian Ocean. The northward-propagating intraseasonal modes trigger the monsoon in some early-onset years. The realistic phase initialization of these modes improves the forecasts of the associated earlier-than-normal monsoon onsets. The prediction of late onsets is not noticeably improved by the initialization of the atmosphere. It is suggested that late onsets of the monsoon are too far away from the start date of the forecasts to conserve enough memory of the intraseasonal oscillation (ISO) anomalies and of the improved representation of the mean state in the initial conditions.

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