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During past glacial‐interglacial cycles, the boreal summer insolation is the most crucial external forcing for climate change. However, the question of whether summer insolation is a key forcing on temperatures in the boreal tropics remains under debate, hampering our understanding of climate change at low latitudes. To shed further light on this issue, we performed a series of equilibrium simulations with the NorESM‐L model over the past 425 ka. Our simulations show that in the boreal tropical monsoon region, the simulated annual temperature is anti‐phased towards the boreal summer insolation. This antiphase relation is also supported by some available geological data. Additional diagnostic analyses reveal that the tropical warmth throughout the year is more reliant on winter temperatures than on summer temperatures. This stands in contrast to the situation in middle to high latitudes, particularly in the Mediterranean region. Further correlation analysis and spectrum analysis suggest that the annual temperature in boreal tropics is highly linked to local winter insolation. Our results highlight complex hydrothermal configurations in the boreal tropics, suggesting a decoupling of temperature and precipitation. Specifically, variations in annual temperature and precipitation in the boreal tropics are driven by distinct patterns of seasonal insolation. We deduce that the unique hydrothermal configurations in North Africa may have influenced the dispersal of early humans out of Africa. Plain Language Summary: On the orbital timescale, whether the temperature in boreal tropics is driven by boreal summer insolation still remains unclear. In this study, we conduct a comprehensive analysis of simulated results spanning the 425 ka. Our findings indicate that the annual temperature in boreal tropics is anti‐phased to the local summer insolation. Specifically, when local summer insolation is high (low), overall cooling (warming) occurs in the North African and South Asian monsoon regions. Some available paleo‐temperature records from the tropics also provide partial support for our simulation results. The temperature pattern in the boreal tropics is linked to the strong internal feedback in the summer from the unique climate background of the tropics, which results in relatively slight summer cooling at high boreal summer insolation, while the annual temperature is largely dependent on winter temperatures driven by local winter insolation. Our simulations reveal highly complex hydrothermal configurations in the boreal tropics on the orbital timescale, suggesting a decoupling of temperature and precipitation, with the former influenced by winter insolation and the latter forced by summer insolation. Key Points: The temperature in boreal tropical monsoon regions is anti‐phased to the boreal summer insolationThe annual temperature in boreal tropics is more dependent on the winter than summer temperaturesThe key role of local winter insolation in regulating the boreal tropical temperature is closely linked to its unique climatic background [ABSTRACT FROM AUTHOR]

The late Pliocene is a pre-Quaternary warming period compared to the preindustrial period. Here, based on the updated PRISM4 (Pliocene Research, Interpretation and Synoptic Mapping version 4) boundary conditions from the Pliocene Model Intercomparison Project phase 2 (PlioMIP2), seven experiments are conducted to simulate the global monsoon in the late Pliocene interglacial period and further investigate the impacts from changes in the individual boundary conditions by using the Community Earth System Model (CESM 1.0.4). The simulated late Pliocene interglacial climate is generally warmer and wetter than the preindustrial period climate, with an expanded monsoon domain, particularly in North Africa, Asia and Australia. The differences in topography, vegetation and lakes outside of Greenland and Antarctica account for the greatest contribution to monsoon changes. Moreover, orbital parameter variations further significantly affect monsoon domains and lead to significant fluctuations in monsoon precipitation and winds on the orbital scale, and the changed magnitude is even larger than that between the late Pliocene and preindustrial period when orbital forcing is not considered. [ABSTRACT FROM AUTHOR]

Using model results from the first phase of the Pliocene Model Intercomparison Project (PlioMIP) and four experiments with CAM4, the intensified African summer monsoon (ASM) in the mid-Piacenzian and corresponding mechanisms are analyzed. The results from PlioMIP show that the ASM intensified and summer precipitation increased in North Africa during the mid-Piacenzian, which can be explained by the increased net energy in the atmospheric column above North Africa. Further experiments with CAM4 indicated that the combined changes in the mid-Piacenzian of atmospheric CO concentration and SST, as well as the vegetation change, could have substantially increased the net energy in the atmospheric column over North Africa and further intensified the ASM. The experiments also demonstrated that topography change had a weak effect. Overall, the combined changes of atmospheric CO concentration and SST were the most important factor that brought about the intensified ASM in the mid-Piacenzian. [ABSTRACT FROM AUTHOR]