Abstract El Niño’s influence on the subtropical northwest (NW) Pacific climate increased after regime shift of 1970s. This is manifested in well-organized atmospheric anomalies suppressed convection and a surface anticyclone during summer (June–August) Niño decay year [JJA(1)], season when equatorial sea temperature (SST) have dissipated. In situ observations ocean–atmospheric reanalyses are used to investigate mechanisms for interdecadal change. During JJA(1), Niño–Southern Oscillation...

Abstract El Niño–Southern Oscillation (ENSO) induces climate anomalies around the globe. Atmospheric general circulation model simulations are used to investigate how ENSO-induced teleconnection patterns during boreal winter might change in response global warming Pacific–North American sector. As models disagree on changes amplitude and spatial pattern of ENSO warming, for simplicity same sea surface temperature (SST) is prescribed before after warming. In a warmer climate, precipitation...

Abstract The response of the Indian Ocean dipole (IOD) mode to global warming is investigated based on simulations from phase 5 Coupled Model Intercomparison Project (CMIP5). In increased greenhouse gases, an IOD-like pattern appears in equatorial Ocean, with reduced (enhanced) east (west), easterly wind trend, and thermocline shoaling east. Despite a strengthened feedback eastern interannual variance IOD remains largely unchanged sea surface temperature (SST) as atmospheric zonal weaken...

Abstract Low-frequency modulation and change under global warming of the Indian Ocean dipole (IOD) mode are investigated with a pair multicentury integrations coupled ocean–atmosphere general circulation model: one constant climate forcing forced by increasing greenhouse gas concentrations. In unforced simulation, there is significant decadal multidecadal IOD variance. The mean thermocline depth in eastern equatorial (EEIO) important for slow modulation, skewness, ENSO correlation IOD. With...

Slow modulation of interannual variability and its relationship to El Niño–Southern Oscillation (ENSO) is investigated for the period 1870–2007 using shipboard surface meteorological observations along a frequently traveled track across north Indian Ocean (NIO; from Gulf Aden through Malacca Strait) South China Sea (to Luzon Strait). During decades in late nineteenth–early twentieth century century, Niño–induced NIO warming persists longer than during 1910s–mid-1970s, well into summer...

Abstract How El Niño–Southern Oscillation (ENSO) will change under global warming affects changes in extreme events around the world. The of ENSO amplitude is investigated based on historical simulations and representative concentration pathway (RCP) 8.5 experiments phase 5 Coupled Model Intercomparison Project (CMIP5). projected highly uncertain with large intermodel uncertainty. By using relative sea surface temperature (SST) as a measure convective instability, this study finds that...

Abstract Observational evidence and climate model experiments suggest a slowdown of the Atlantic Meridional Overturning Circulation (AMOC) since mid-1990s. Increased greenhouse gases declined anthropogenic aerosols (AAs) over North America Europe are believed to contribute AMOC slowdown. Asian AAs continue increase but associated impact has been unclear. Using ensembles simulations, here we show that radiative cooling resulting from increased drives an reduction. The Asia generate...

During 2010 to 2020, Northeast Pacific (NEP) sea surface temperature (SST) experienced the warmest decade ever recorded, manifested in several extreme marine heatwaves, referred as “warm blob” events, which severely affect ecosystems and weather along west coast of North America. While year-to-year internal climate variability has been suggested a cause individual causes continuous dramatic NEP SST warming remain elusive. Here, we show that other than greenhouse gas (GHG) forcing, rapid...

Abstract The time-dependent response of sea surface temperature (SST) to global warming and the associated atmospheric changes are investigated based on a 1% yr−1 CO2 increase quadrupling experiment Geophysical Fluid Dynamics Laboratory Climate Model, version 2.1. SST consists fast component, for which ocean mixed layer is in quasi equilibrium with radiative forcing, slow component owing gradual deeper beneath thermocline. A diagnostic method proposed isolate spatial patterns responses. deep...

Abstract The present study investigates interdecadal modulations of the El Niño–Southern Oscillation (ENSO) influence on climate northwest Pacific (NWP) and East Asia (EA) in early boreal summer following a winter ENSO event, based 19 simulations from phase 5 Coupled Model Intercomparison Project (CMIP5). In historical run, 8 out models capture realistic relationship between NWP climate—an anomalous anticyclone develops over Niño event—and this correlation. During periods when association is...

In March 2017, sea surface temperatures off Peru rose above 28 °C, causing torrential rains that affected the lives of millions people. This coastal warming is highly unusual in it took place with a weak La Niña state. Observations and ocean model experiments show downwelling Kelvin waves caused by strong westerly wind events over equatorial Pacific, together anomalous northerly winds, are important. Atmospheric further winds forced warming. Taken together, these results indicate positive...

Abstract The development of the Indian Ocean basin (IOB) mode and its change under global warming are investigated using a pair integrations with Geophysical Fluid Dynamics Laboratory Climate Model version 2.1 (CM2.1). In simulation constant climate forcing, El Niño–induced over tropical (TIO) capacitor effect on summer northwest Pacific reproduced realistically. forced by increased greenhouse gas concentrations, IOB enhanced in persistence following Niño, even though ENSO itself weakens...

Abstract This study evaluates the simulation of Indian Ocean Basin (IOB) mode and relevant physical processes in models from phase 5 Coupled Model Intercomparison Project (CMIP5). Historical runs 20 CMIP5 are available for analysis. They reproduce IOB its close relationship to El Niño–Southern Oscillation (ENSO). Half capture key processes: a downwelling oceanic Rossby wave southern tropical (TIO) precedes development boreal fall triggers an antisymmetric wind anomaly pattern across equator...

Abstract The eastern tropical Pacific features strong climatic asymmetry across the equator, with intertropical convergence zone (ITCZ) displaced north of equator most time. In February–April (FMA), seasonal warming in Southern Hemisphere and cooling Northern weaken asymmetry, a double ITCZ appears zonal rainband on either side equator. Results from an analysis precipitation variability reveal that relative strength between northern southern varies one year to another this meridional seesaw...

Abstract This study found that the relationship between Indian Summer Monsoon Rainfall (ISMR) and El Niño‐Southern Oscillation (ENSO) has recovered since 2001, strength is closely related to summer tropical Ocean (TIO) sea surface temperature (SST) anomaly, with TIO warming (cooling) indicating a stronger (weaker) relationship. Under same Niño/La Niña scenario, different signs of anomaly indicate distinct atmospheric circulation anomalies over Ocean, thus affecting ISMR–ENSO The principally...

The tropical Pacific warming pattern since the 1950s exhibits two centers in western (WP) and eastern (EP), encompassing an equatorial central (CP) cooling a hemispheric asymmetry subtropical EP. underlying mechanisms of this remain debated. Here, we conduct ocean heat decompositions coupled model large ensembles to unfold role wind-driven circulation. When wind changes are suppressed, historical radiative forcing induces northeastern warming, thus causing that extends toward WP. EP is...

Abstract This study investigates the interannual variability of North Pacific Central Mode Water (CMW) under phase relationship El Niño–Southern Oscillation (ENSO) and Decadal (PDO), based on multiple observational data sets. Peaks troughs CMW are primarily observed when ENSO PDO in phase, but only moderate variation out phase. In Niño spring during positive PDO, extreme ventilation takes place central (180°–155°W, 30°–40°N), where no local occurs for other cases. Such induces stronger...