The role of El Niño in the global energy redistribution: a case study in the mid-Holocene

It has been shown that El Niño events contribute to discharge the warm pool excess of energy out of the tropical Pacific. In a different climate, the energetic budget in the tropical Pacific is altered, which might have an effect on the El Niño amplitude and/or occurrence and thereby on the role of El Niño on energy redistribution. The mid-Holocene period (6 ka BP) offers a good example of changes in the distribution of incoming solar energy. In particular, the equator-pole gradient was weaker compared to the modern period. We analyze long stable simulations of the mid-Holocene and the pre-industrial era and discuss the mean- and El Niño-related energy transports in the two climates. We show that the role of global energy pump played by the tropical Pacific is reduced in the mid-Holocene in our simulation, both in long-term mean and during El Niño years. We demonstrate that this is not only a direct response to insolation forcing but this is further amplified by changes in internal processes. We analyze the relative role of El Niño events in the Pacific discharge in the two climates and show that it is reduced in the mid-Holocene, i.e. the fraction of the Pacific discharge that is due to El Niño is reduced. This is mainly due to reduction in the occurrence of El Niño events. This work gives a new approach to address El Niño changes, from the perspective of the role of El Niño in global energy redistribution.

[1]  Ngar-Cheung Lau,et al.  Remote Sea Surface Temperature Variations during ENSO: Evidence for a Tropical Atmospheric Bridge , 1999 .

[2]  R. Seager,et al.  Suppression of El Niño during the Mid‐Holocene by changes in the Earth's orbit , 2000 .

[3]  ENSO-driven interhemispheric Pacific mass transports , 2014 .

[4]  E. Guilyardi,et al.  ENSO representation in climate models: from CMIP3 to CMIP5 , 2013, Climate Dynamics.

[5]  S. Bony,et al.  Climate change projections using the IPSL-CM5 Earth System Model: from CMIP3 to CMIP5 , 2013, Climate Dynamics.

[6]  John E. Kutzbach,et al.  Modeling climate shift of El Nino variability in the Holocene , 2000 .

[7]  L. Haimberger,et al.  Poleward Atmospheric Energy Transports and Their Variability as Evaluated from ECMWF Reanalysis Data , 2012 .

[8]  R. Ganeshram,et al.  Palaeoclimate reconstructions reveal a strong link between El Niño-Southern Oscillation and Tropical Pacific mean state , 2013, Nature Communications.

[9]  P. Braconnot,et al.  Monsoon response to changes in Earth's orbital parameters: comparisons between simulations of the Eemian and of the Holocene , 2008 .

[10]  P. Braconnot,et al.  Changes in the ENSO/SPCZ relationship from past to future climates , 2015 .

[11]  P. Braconnot,et al.  Early and mid-Holocene climate in the tropical Pacific: seasonal cycle and interannual variability induced by insolation changes , 2012 .

[12]  S. Bony,et al.  The LMDZ4 general circulation model: climate performance and sensitivity to parametrized physics with emphasis on tropical convection , 2006 .

[13]  K. Wyrtki,et al.  El Niño—The Dynamic Response of the Equatorial Pacific Oceanto Atmospheric Forcing , 1975 .

[14]  K. Trenberth,et al.  The Response of Tropical Atmospheric Energy Budgets to ENSO , 2013 .

[15]  P. Braconnot,et al.  Impact of Earth’s orbit and freshwater fluxes on Holocene climate mean seasonal cycle and ENSO characteristics , 2012, Climate Dynamics.

[16]  Fei-Fei Jin,et al.  An Equatorial Ocean Recharge Paradigm for ENSO. Part I: Conceptual Model , 1997 .

[17]  A. Timmermann,et al.  The response of ENSO flavors to mid‐Holocene climate: Implications for proxy interpretation , 2015 .

[18]  C. Hewitt,et al.  A multi-model analysis of the role of the ocean on the African and Indian monsoon during the mid-Holocene , 2005 .

[19]  P. Braconnot,et al.  Ocean Feedback in Response to 6 kyr BP Insolation , 2000 .

[20]  Zhengyu Liu.  NOTES AND CORRESPONDENCE A Simple Model Study of ENSO Suppression by External Periodic Forcing , 2002 .

[21]  Bin Wang,et al.  The Role of Moist Processes in Shortwave Radiative Feedback during ENSO in the CMIP5 Models , 2015 .

[22]  P. Delecluse,et al.  OPA 8.1 Ocean General Circulation Model reference manual , 1998 .

[23]  Kevin E. Trenberth,et al.  An apparent hiatus in global warming? , 2013 .

[24]  M. Collins,et al.  Links between tropical Pacific seasonal, interannual and orbital variability during the Holocene , 2016 .

[25]  J. Kutzbach,et al.  The Sensitivity of the African-Asian Monsoonal Climate to Orbital Parameter Changes for 9000 Years B.P. in a Low-Resolution General Circulation Model. , 1982 .

[26]  G. Cabioch,et al.  Early mid‐Holocene SST variability and surface‐ocean water balance in the southwest Pacific , 2012 .

[27]  M. Balmaseda,et al.  On the Energy Exchange between Tropical Ocean Basins Related to ENSO , 2014 .

[28]  E. Cook,et al.  Variability in the El Niño-Southern Oscillation Through a Glacial-Interglacial Cycle , 2001, Science.

[29]  Karl E. Taylor,et al.  An overview of CMIP5 and the experiment design , 2012 .

[30]  P. Braconnot,et al.  Tropical Pacific mean state and ENSO changes: sensitivity to freshwater flux and remnant ice sheets at 9.5 ka BP , 2015, Climate Dynamics.

[31]  A. Oort,et al.  Observed Interannual Variability in the Hadley Circulation and Its Connection to ENSO , 1996 .

[32]  Helen McGregor,et al.  Mid‐Holocene ENSO: Issues in quantitative model‐proxy data comparisons , 2008 .

[33]  J. Bjerknes.  ATMOSPHERIC TELECONNECTIONS FROM THE EQUATORIAL PACIFIC1 , 1969 .

[34]  André Berger,et al.  Long-term variations of daily insolation and Quaternary climatic changes , 1978 .

[35]  R. Edwards,et al.  Highly Variable El Niño–Southern Oscillation Throughout the Holocene , 2013, Science.

[36]  M. Carré,et al.  Reconstructing El Niño-Southern Oscillation activity and ocean temperature seasonality from short-lived marine mollusk shells from Peru , 2013 .

[37]  Jung Choi,et al.  Mid-Holocene tropical Pacific climate state, annual cycle, and ENSO in PMIP2 and PMIP3 , 2013, Climate Dynamics.

[38]  I. C. Prentice,et al.  A dynamic global vegetation model for studies of the coupled atmosphere‐biosphere system , 2005 .

[39]  Yan Zhao,et al.  Evaluation of climate models using palaeoclimatic data , 2012 .

[40]  Sandy P. Harrison,et al.  Monsoon changes for 6000 years ago: Results of 18 simulations from the Paleoclimate Modeling Intercomparison Project (PMIP) , 1999 .

[41]  K. Hanawa,et al.  Heat Content Variability Related to ENSO Events in the Pacific , 2003 .

[42]  David M. Anderson,et al.  Variability of El Niño/Southern Oscillation activity at millennial timescales during the Holocene epoch , 2002, Nature.

[43]  Pierre Friedlingstein,et al.  Key features of the IPSL ocean atmosphere model and its sensitivity to atmospheric resolution , 2010 .

[44]  M. Maqueda,et al.  Sensitivity of a global sea ice model to the treatment of ice thermodynamics and dynamics , 1997 .

[45]  E. Guilyardi,et al.  ENSO at 6ka and 21ka from ocean–atmosphere coupled model simulations , 2008 .

[46]  S. Harrison,et al.  Mid-Holocene monsoons: a multi-model analysis of the inter-hemispheric differences in the responses to orbital forcing and ocean feedbacks , 2012, Climate Dynamics.

[47]  E. Guilyardi,et al.  Mid-Holocene and Last Glacial Maximum climate simulations with the IPSL model—part I: comparing IPSL_CM5A to IPSL_CM4 , 2013, Climate Dynamics.

[48]  Kevin E. Trenberth,et al.  The Annual Cycle of the Energy Budget. Part II: Meridional Structures and Poleward Transports , 2008 .

[49]  M. Kageyama,et al.  Shortwave forcing and feedbacks in Last Glacial Maximum and Mid-Holocene PMIP3 simulations , 2015, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[50]  M. Gagan,et al.  Western Pacific coral δ18O records of anomalous Holocene variability in the El Niño–Southern Oscillation , 2004 .

[51]  Qinyu Liu,et al.  Periodic Forcing and ENSO Suppression in the Cane-Zebiak Model , 2005 .

[52]  K. Trenberth,et al.  Interannual variations in the atmospheric heat budget , 2002 .

[53]  Anthony J. Broccoli,et al.  Climate Feedbacks in Response to Changes in Obliquity , 2011 .