scholarly journals Changes in the in-phase relationship between the Indian and subsequent Australian summer monsoons during the past five decades

2007 ◽  
Vol 25 (9) ◽  
pp. 1929-1933 ◽  
Author(s):  
J.-Y. Yu ◽  
M. A. Janiga
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Phase Relationship ◽  
Austral Summer ◽  
Australian Monsoon ◽  
The Past ◽  
The Pacific ◽  
Australian Summer Monsoon ◽  
Sst Anomalies ◽  
Australian Summer

Abstract. This study examines the decadal changes in the in-phase relationship between Indian summer monsoon and the subsequent Australian summer monsoon using observational data from 1950–2005. The in-phase relationship is the tendency for a strong Indian summer monsoon to be followed by a strong Australian summer monsoon and vice versa. It is found that the in-phase relationship was weak during the late 1950s and early 1960s, strengthened to a maximum in the early 1970s just before the 1976/77 Pacific climate shift, then declined until the late 1990s. Pacific SST anomalies are noticed to have strong persistence from boreal to austral summer, providing the memory to connect the Indian and subsequent Australian summer monsoon. The simultaneous correlation between the Pacific SST anomalies and the Indian summer monsoon is always strong. It is the weakening and strengthening of the simultaneous correlation between the Australian summer monsoon and the Pacific SST anomalies that contributes to the decadal variations of the in-phase monsoon relation. This study suggests that the interaction between the Australian monsoon and the Pacific Ocean is crucial to tropical climate variability and has experienced significant changes over the past five decades.

scholarly journals Role of the Indian Ocean in the Biennial Transition of the Indian Summer Monsoon

2007 ◽  
Vol 20 (10) ◽  
pp. 2147-2164 ◽  
Author(s):  
Renguang Wu ◽  
Ben P. Kirtman
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Indian Monsoon ◽  
Coupled Model ◽  
The Pacific ◽  
The Indian Ocean ◽  
Biennial Variability ◽  
Sst Anomalies

Abstract The biennial variability is a large component of year-to-year variations in the Indian summer monsoon (ISM). Previous studies have shown that El Niño–Southern Oscillation (ENSO) plays an important role in the biennial variability of the ISM. The present study investigates the role of the Indian Ocean in the biennial transition of the ISM when the Pacific ENSO is absent. The influence of the Indian and Pacific Oceans on the biennial transition between the ISM and the Australian summer monsoon (ASM) is also examined. Controlled numerical experiments with a coupled general circulation model (CGCM) are used to address the above two issues. The CGCM captures the in-phase ISM to ASM transition (i.e., a wet ISM followed by a wet ASM or a dry ISM followed by a dry ASM) and the out-of-phase ASM to ISM transition (i.e., a wet ASM followed by a dry ISM or a dry ASM followed by a wet ISM). These transitions are more frequent than the out-of-phase ISM to ASM transition and the in-phase ASM to ISM transition in the coupled model, consistent with observations. The results of controlled coupled model experiments indicate that both the Indian and Pacific Ocean air–sea coupling are important for properly simulating the biennial transition between the ISM and ASM in the CGCM. The biennial transition of the ISM can occur through local air–sea interactions in the north Indian Ocean when the Pacific ENSO is suppressed. The local sea surface temperature (SST) anomalies induce the Indian monsoon transition through low-level moisture convergence. Surface evaporation anomalies, which are largely controlled by surface wind speed changes, play an important role for SST changes. Different from local air–sea interaction mechanisms proposed in previous studies, the atmospheric feedback is not strong enough to reverse the SST anomalies immediately at the end of the monsoon season. Instead, the reversal of the SST anomalies is accomplished in the spring of the following year, which in turn leads to the Indian monsoon transition.

scholarly journals Possible Role of the Indian Ocean in the In-Phase Transition of the Indian-to-Australian Summer Monsoon

2008 ◽  
Vol 21 (21) ◽  
pp. 5727-5741 ◽  
Author(s):  
Renguang Wu
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Southern Oscillation ◽  
Tropical Indian Ocean ◽  
Australian Summer Monsoon ◽  
The Indian Ocean ◽  
Numerical Model Experiments ◽  
Sst Anomalies ◽  
Australian Summer

Abstract Analysis of observations shows that in-phase transitions from the Indian summer monsoon (ISM) to the Australian summer monsoon (ASM) have occurred both in El Niño–Southern Oscillation (ENSO) and non-ENSO years. The present study investigates possible roles of the Indian Ocean in the in-phase ISM-to-ASM transitions. It is shown that an anomalous ISM leads to sea surface temperature (SST) anomalies in the tropical Indian Ocean through wind–evaporation effects. The resultant Indian Ocean SST anomalies induce an anomalous ASM of the same sign as the ISM through an anomalous east–west circulation over the eastern Indian Ocean and the Maritime Continent–northern Australia. The results indicate that the in-phase ISM-to-ASM transitions in non-ENSO years can be accomplished through monsoon–Indian Ocean interactions. The results of observational analysis are confirmed with numerical model experiments.

scholarly journals The Role of Air–Sea Interaction for Prediction of Australian Summer Monsoon Rainfall

2012 ◽  
Vol 25 (4) ◽  
pp. 1278-1290 ◽  
Author(s):  
Harry H. Hendon ◽  
Eun-Pa Lim ◽  
Guo Liu
Keyword(s):  
Summer Monsoon ◽  
Coupled Model ◽  
Intrinsic Property ◽  
Forecast Model ◽  
Forecast Skill ◽  
Northern Australia ◽  
The North ◽  
Australian Summer Monsoon ◽  
Sst Anomalies ◽  
Australian Summer

Abstract Forecast skill for seasonal mean rainfall across northern Australia is lower during the summer monsoon than in the premonsoon transition season based on 25 years of hindcasts using the Predictive Ocean Atmosphere Model for Australia (POAMA) coupled model seasonal forecast system. The authors argue that this partly reflects an intrinsic property of the monsoonal system, whereby seasonally varying air–sea interaction in the seas around northern Australia promotes predictability in the premonsoon season and demotes predictability after monsoon onset. Trade easterlies during the premonsoon season support a positive feedback between surface winds, SST, and rainfall, which results in stronger and more persistent SST anomalies to the north of Australia that compliment the remote forcing of Australian rainfall from El Niño in the Pacific. After onset of the Australian summer monsoon, this local feedback is not supported in the monsoonal westerly regime, resulting in weaker SST anomalies to the north of Australia and with lower persistence than in the premonsoon season. Importantly, the seasonality of this air–sea interaction is captured in the POAMA forecast model. Furthermore, analysis of perfect model forecasts and forecasts generated by prescribing observed SST results in largely the same conclusion (i.e., significantly lower actual and potential forecast skill during the monsoon), thereby supporting the notion that air–sea interaction contributes to intrinsically lower predictability of rainfall during the monsoon.

scholarly journals Australian Summer Monsoon variability in the past 14,000 years revealed by IODP Expedition 356 sediments

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Takeshige Ishiwa ◽  
Yusuke Yokoyama ◽  
Lars Reuning ◽  
Cecilia M. McHugh ◽  
David De Vleeschouwer ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
The Past ◽  
Monsoon Variability ◽  
Australian Summer Monsoon ◽  
Australian Summer

scholarly journals The Australian monsoon Part-I : Climatological features and the Asian connection

MAUSAM ◽  
2021 ◽  
Vol 51 (2) ◽  
pp. 127-154
Author(s):  
KSHUDIRAM SARA ◽  
SURANJANA SARA
Keyword(s):  
Summer Monsoon ◽  
Meteorological Variables ◽  
Australian Monsoon ◽  
Weather And Climate ◽  
Australian Summer Monsoon ◽  
Relationship Of ◽  
Australian Summer

Climatological fields of several meteorological variables associated with the Australian summer monsoon, as revealed by NCEP/NCAR reanalysis, are reviewed in the context of observed weather and climate over the continent and surrounding regions. Inter-hemispheric distributions of pressure, temperature and circulation features suggest a see-saw relationship of the Australian monsoon with the monsoons of Asia during both summer and winter. Computed values of cross-equatorial fluxes of air appear to lend credence to this hypothesis.

scholarly journals Roles of the Indian Ocean in the Australian Summer Monsoon–ENSO Relationship

2007 ◽  
Vol 20 (18) ◽  
pp. 4768-4788 ◽  
Author(s):  
Renguang Wu ◽  
Ben P. Kirtman
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Negative Correlation ◽  
Coupled Model ◽  
Term Change ◽  
Australian Summer Monsoon ◽  
The Indian Ocean ◽  
Sst Anomalies ◽  
Australian Summer

Abstract A negative correlation is observed between interannual variations of the Australian summer monsoon (ASM) and El Niño–Southern Oscillation (ENSO). This negative relationship is well simulated in the Center for Ocean–Land–Atmosphere (COLA) interactive ensemble coupled general circulation model (CGCM). The present study investigates roles of the Indian Ocean in the ASM–ENSO relationship through controlled numerical experiments with the COLA CGCM. It is found that air–sea coupling in the Indian Ocean plays an important role in maintaining the negative ASM–ENSO relationship. When the Indian Ocean is decoupled from the atmosphere, the ASM–ENSO relationship is significantly weakened or even masked by the internal atmospheric variability. This change in the ASM–ENSO relationship is related to complementary roles of Indian Ocean sea surface temperature (SST) anomalies in the ASM variability and feedbacks from the Indian Ocean on ENSO. Without a coupled Indian Ocean, the ENSO amplitude is reduced, leading to a decrease in the ENSO-induced ASM variability, and the constructive impacts of the Indian Ocean SST anomalies on the ASM variability are substantially reduced. This reduces the ASM variability related to ENSO. Consistent with the change in the ASM–ENSO relationship, the local air–sea relationship in the ASM region displays important differences with and without a coupled Indian Ocean. The long-term change in the ASM–ENSO relationship is related to that in ENSO amplitude in the interactive ensemble coupled model. A relatively higher (lower) negative correlation occurs in periods of larger (smaller) ENSO amplitude. This relationship, however, is not clear in the anomaly coupled model with only one atmospheric realization. This difference is attributed to changes in the signal-to-noise ratio in the ASM variability. A comparison is made with observations and the long-term change in the Indian summer monsoon (ISM)–ENSO relationship in the model.

Sign in / Sign up

Export Citation Format

Share Document