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The influence of winter circumglobal teleconnection （CGT） on the interannual variability of winter precipitation in the Southeast Asian low-latitude highlands were statistically analyzed using ERA5 reanalysis data from the European Centre for Medium-Range Weather Forecasts （ECMWF）， monthly mean precipitation data from the Climate Hazards Group Infrared Precipitation with Station data （CHIRPS） developed by the United States Geological Survey and the University of California and the monthly mean precipitation data of the Global Precipitation Climatology Project （GPCP） provided by the Global Precipitation Climatology Center.Results of correlation analysis show that the CGT presents two main patterns with approximately the same variance contribution rate.On the vertical direction， the CGT shows an equivalent barotropic structure with four anomalous centers.During the CGT positive phase， the negative anomalous centers are located near the Mediterranean Sea and the Indian Peninsula， and the positive anomalous centers near the Arabian Peninsula and Southeast Asian low-latitude highlands.The first mode of CGT （CGT1） significantly correlates with winter precipitation over the Southeast Asian low-latitude highlands on the interannual time scale.When the CGT1 is in the positive phase in winter， the anomalous "anticyclone， cyclone， anticyclone， cyclone" control the Western Europe， the northwestern Arabian Peninsula， the Arabian Sea and Southeast Asian low-latitude highlands， respectively.The anomalous southwesterly wind on the east side of the anomalous cyclone will increase the water vapor from the Bay of Bengal and the South China Sea to the Southeast Asian low-latitude highlands.The more water vapor converged and condensed in Southeast Asian low-latitude highlands finally results in heavier winter precipitation over the Southeast Asian low-latitude highlands.On the contrary， when the CGT1 is in the negative phase in winter， the Western Europe， the northwestern Arabian Peninsula， the Arabian Sea and the Southeast Asian low-latitude highlands are controlled by the anomalous "cyclone， anticyclone， cyclone， anticyclone".The anomalous northeast wind on the east flank of the anomalous anticyclone will reduce the water vapor from the Bay of Bengal and the South China Sea to the Southeast Asian low-latitude highlands.The anomalous divergence and descending motion further lead to less precipitation in winter over the Southeast Asian low-latitude highlands.The significant positive correlation between CGT and precipitation over the Southeast Asian low-latitude highlands， sharing almost the same key physical process as winter， can be observed in December， January and February.Results of typical case further confirm the key physical process through which the CGT modulates the interannual variability of winter precipitation over the Southeast Asian low-latitude highlands.

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This study investigated the covariation of thermal conditions of the Southeast Asian low-latitude highlands (SEALLH) and variability of the summer East Asia–Pacific (EAP) or Pacific–Japan (PJ) teleconnection pattern using ERA5 reanalysis data and numerical experiments. Statistical analysis and physical diagnosis show that the EAP/PJ teleconnection pattern is significantly related to the seesaw mode of diabatic heating over the SEALLH in summer on the interannual time scale. When enhanced diabatic heating occurs over the central–northern SEALLH with weakened diabatic heating over the southern SEALLH, anomalous easterly and westerly winds, fitting the quasi-geostrophic theory, appear over the southern and central–northern SEALLH, receptively. These anomalous winds are propitious to the EAP/PJ teleconnection pattern in the "+, −, +" phase from the western North Pacific to northeast Asia. Once a significant relationship has been established in late spring, it can persist through to the following summer. Sensitivity experiments identified the key physical process linking the variability of the thermal conditions over the SEALLH to the summer EAP/PJ teleconnection pattern on an interannual time-scale. [ABSTRACT FROM AUTHOR]

The timing of the Bay of Bengal summer monsoon (BOBSM) onset has implications for the evolution of the Asian summer monsoon and associated precipitation. This study employs Japanese 55-year Reanalysis and NOAA's Gridded Precipitation Reconstruction over Land data to explore the spatiotemporal variation in the thermal influence of the Southeast Asian low-latitude highlands (SEALLH) and its effect on the BOBSM onset date. There is a significant correlation between pre-monsoon season (February–April) shortwave radiative heating (SWH) in the SEALLH and BOBSM onset in the interannual time scale. During the enhanced SWH, an anomalous vertical circulation, which converges and ascends in the lower troposphere over the SEALLH and converges and descends in the upper troposphere north of the Bay of Bengal (BOB), develops over the SEALLH–north of BOB during the pre-monsoon season with anticlockwise rotation. The warmer air mass resulting from the adiabatic heating is accumulated around the north of BOB by the insulation effect related to the anomalous vertical circulation. By facilitating the reversal of the land-sea thermal contrast, the warmer upper troposphere over the north of the BOB causes a 16-day earlier onset of the BOBSM than the case of weakened SWH. The findings shed light on subsequent research into the thermal effects of the SEALLH on Asian summer monsoon variability. • Stronger SWH of the SEALLH generally relates to earlier onset of the BOBSM. • An anomalous anticlockwise circulation excited by the stronger SWH is the key node linking the thermal effect of the SEALLH and BOBSM onset. • The insulation effect of the anomalous anticlockwise circulation facilitates the reversal of the north-south thermal contrast. [ABSTRACT FROM AUTHOR]

The Yangtze-Huai River Basin (YHRB) is an economically developed area and one of the most densely populated regions in China. Based on ERA5 reanalysis and Meiyu monitoring data, this study investigates the relationship between interannual variability in atmospheric latent heating (LH) over the Southeast Asian low-latitude highlands (SEALLH) during early summer and the Meiyu onset date (MOD) in the YHRB. The mean MOD is 9 June, with a quasi-6-year interannual oscillation period. A stronger early summer LH over the SEALLH coincides with earlier MOD; below 500 hPa, LH increases with height and drives an anomalous southwesterly airflow from the Bay of Bengal (BOB) to the SEALLH via β effects. Circulation over the western North Pacific (WNP) is dominated by an anomalous anticyclone, causing the WNP subtropical high (WNPSH) to extend westward and northward. Continuous positive LH anomalies over the SEALLH cause anomalous southwesterly winds to transport moist enthalpy air masses from low latitudes into the YHRB, resulting in abnormal convergence there. Favorable dynamic and thermal conditions drive enhanced precipitation over the YHRB, eventually leading to a MOD that is 13 days earlier than that during periods when early summer LH is relatively weak over the SEALLH. This result potentially supports our capacity to predict the Meiyu in the YHRB. • The mean Meiyu onset date in the YHRB is 9 June, with a quasi-6-year interannual oscillation period. • The Meiyu onset date in the YHRB is significantly controlled by the May atmospheric latent heating over the SEALLH on interannual time scale. • The May atmospheric latent heating over the SEALLH causes the development of southwesterly winds in the YHRB via β effects, leading to an earlier onset of the Meiyu. [ABSTRACT FROM AUTHOR]

Using ERA5 reanalysis data, this study reveals the relationship between variations of winter surface solar radiation (SSR) over the Southeast Asian low-latitude highlands (SEALLH) and the circumglobal teleconnection (CGT). The results indicate that the winter SSR shows significant interannual variability with a monopole pattern over the SEALLH. The winter CGT significantly modifies the interannual variability of the simultaneous SSR over the SEALLH. When the CGT is in its positive phase, a wave train appears over the central-eastern Mediterranean, Arabian Peninsula, Indian Peninsula, and East Asia with anomalous "northerly, southerly, northerly, southerly" nondivergent meridional wind. The associated southerly wind anomalies around the SEALLH favor greater transport of water vapor from the Bay of Bengal that converges over the SEALLH. The consequent increase of cloud cover in the lower–middle troposphere and aerosol optical depth (AOD) reduce the winter SSR over the SEALLH. When the CGT is in its negative phase, the anomalous northerly wind with anomalous divergence increases the winter SSR over the SEALLH by decreasing both cloud cover in the lower–middle troposphere and the AOD. • The interannual variability of winter SSR shows a monopole pattern over the SEALLH. • CGT impacts the interannual variability of winter SEALLH SSR via exciting a gyre. • Winter SEALLH SSR is regulated by local cloud cover and AOD induced by the gyre. [ABSTRACT FROM AUTHOR]