The Response Of High Latitude North Atlantic Heat Flux To Global Warming

Atlantic Meridional Overturning Circulation(AMOC)transport huge heat from low latitude to the high latitudes North Atlantic(HNA)and then release to the local atmosphere,dominates the local climate pattern and impact the climate changes of North Hemisphere.And the effect is most significant in winter.The measured data show that in the 20th century,under the condition of the global temperature rise,heat flux in HNA decreases,but the decreasing trend is not sure a part of the decrease of the interdecadal scale fluctuation phase or the reducing along the global warming.In this paper,our results,which based on 4 warming scenarios experiments of CMIP5 multiple models,are consistent with observations.Furthermore,our works find that the weakening magnitude of HNA turbulent heat flux is different in winter and summer,the value in winter is larger than summer's.Along with the global warming,the time scale and amplitude of HNA turbulent heat flux in winter is reduced,and warmer the global more the reduced.At the same time,CMIP5 data show that:along with the global warming,AMOC,Atlantic Meridional heat flux,and HNA turbulent heat flux all have a decreasing trend.The bulk formula using control variable method analysis showed that the HNA turbulent heat flux is more sensitive the the change of marine elements under global warming.Combined with a water-hosing experiment,we find the weakened HNA turbulent heat flux is a result of weakened AMOC and its related reduced oceanic heat transport to HNA under global warming.The reduction of the turbulent heat flux in HNA have a significant impact on the climate.With global warming,the CMIP5 multi-models mean sea surface pressure have a HNA-Arctic seesaw phenomenon.The Community Atmosphere Model 5(CAM5)also has this kind of phenomenon in the sensitive experiment,which shows that the phenomenon may be due to reduction in HNA turbulent heat flux.At the same time,the change of HNA turbulent heat flux will also affect the distribution of NAO,local rainfall,local surface air temperature and the rainfall near the equator.