To disentangle the mechanisms how different types of aerosols influence the position of the Intertropical convergence zone (ITCZ), this study explores the impacts of black carbon (BC) and sulfate (SO₄) aerosols on the ITCZ latitudinal position through altering different autoconversion schemes and cumulus parameterizations within a single climate model. To investigate their impacts with a detectable magnitude, we homogeneously perturb the emissions of BC and SO₄ in the year 2000 by 10 and 5 times, respectively. It is found that for 5SO₄ cases, altering the autoconversion scheme not only affects the total (atmosphere plus ocean) anomalous cross-equatorial heat transport, but also modulates the atmospheric portion in it, and thus influences the magnitude of the corresponding ITCZ shift. The atmospheric portion in the 5SO₄-induced total anomalous cross-equatorial heat transport increases with the cloud adjustment to 5SO₄, as longer cloud lifetime can suppress more surface evaporation in the northern hemisphere and increase southern-northern hemispheric energy contrast in the atmosphere. For 10BC cases, it is found that with the increase of cloud adjustment, the corresponding oceanic anomalous cross-equatorial heat transport tends to shift from southward to northward, as larger cloud adjustment means more increase (decrease) of low (high) cloud fraction and less net downward radiation both at the top of the atmosphere and the surface in the northern hemisphere. However, the atmospheric anomalous cross-equatorial heat transport and the consequent ITCZ shift caused by 10BC are affected little. Compared with the altering autoconversion scheme, altering cumulus parameterization has relatively small influences on the 10BC- and 5SO₄-induced anomalous cross-equatorial heat transports and the consequent ITCZ shifts.

中文翻译：

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通过改变不同的自动转换方案和积云参数化探索气溶胶对 ITCZ 位置的影响

为了弄清不同类型的气溶胶如何影响热带辐合带 (ITCZ) 位置的机制，本研究通过改变不同的自动转换方案，探讨了黑碳 (BC) 和硫酸盐 (SO ₄ ) 气溶胶对 ITCZ 纬度位置的影响。单个气候模型中的积云参数化。为了以可检测的幅度研究它们的影响，我们将 2000年 BC 和 SO ₄的排放分别均匀扰动了10 倍和 5 倍。发现对于 5SO ₄在这种情况下，改变自动转换方案不仅会影响总（大气加上海洋）异常的跨赤道热传输，还会调节其中的大气部分，从而影响相应 ITCZ 偏移的幅度。5SO ₄引起的总异常跨赤道热传输中的大气部分随着云调整到5SO _{4 而增加}，因为更长的云寿命可以抑制北半球更多的表面蒸发，并增加大气中南北半球的能量对比。对于 10BC 的情况，发现随着云平差的增加，相应的海洋异常跨赤道热传输趋向于由南向北移动，云平差越大意味着低（高）云比例的增加（减少）越多，大气层顶部和北半球表面的净向下辐射较少。然而，大气异常的跨赤道热传输和由此引起的 10BC 引起的 ITCZ 移动受到的影响很小。与改变自转换方案相比，改变积云参数化对 10BC- 和 5SO _{4 的}影响相对较小引起的异常赤道热传输和随之而来的 ITCZ 移动。