Quantifying the interaction of atmospheric aerosols with incoming solar radiation remains a challenge owing to the limitations associated with measuring aerosol optical properties. This study investigates how the distribution of aerosol properties, whether columnar or vertical, affects the aerosol radiative forcing (ARF) and heating rates (HRs) across different atmospheric layers under cloud-free conditions in the shortwave region. We also assess the atmospheric parameters, namely, pressure, temperature, water vapour density, and ozone density, from in-situ measurements, reanalysis data, and a standard tropical atmosphere to understand their impact on ARF and HR estimates across seasons. Our findings show that aerosol absorption is highest during monsoon, while it is lowest in the winter. Significant atmospheric warming due to aerosols resulted from the substantial cooling at the surface. Columnar properties of aerosols measured at limited or multiple wavelengths yield similar ARF and HR estimates, provided spectral dependency is considered using the Angstrom exponent across seasons. However, the vertical profiles of aerosol extinction, together with a constant single scattering albedo (SSA) along the atmospheric column versus an actual SSA profile, led to notable differences in ARF and HRs, specifically in pre-monsoon and monsoon periods. Free tropospheric aerosol absorption is underestimated when using columnar properties compared to vertical distribution, while boundary layer absorption is overestimated (> 10 Wm-2). The heterogeneity in aerosol types across atmospheric layers significantly influenced aerosol absorption, highlighting the importance of accurate vertical distribution information. HR profiles obtained with vertical distribution reflect the structure of aerosol extinction, whereas those estimated with columnar properties result in smoother profiles that fail to capture altitude gradients. Aerosol-induced HRs are higher within the boundary layer and free troposphere in the monsoon season for all scenarios of defined aerosol properties. These findings underscore the need for actual vertical profile measurements of aerosol properties to quantify aerosol radiation interaction.

中文翻译：

---

气溶胶特性的柱状与垂直分布对短波辐射效应调制的影响


由于测量气溶胶光学特性的局限性，量化大气气溶胶与入射太阳辐射的相互作用仍然是一项挑战。本研究调查了在短波无云条件下，气溶胶特性的分布（无论是柱状还是垂直式）如何影响不同大气层的气溶胶辐射强迫 （ARF） 和加热速率 （HR）。我们还通过原位测量、再分析数据和标准热带大气评估大气参数，即压力、温度、水蒸气密度和臭氧密度，以了解它们对不同季节的 ARF 和 HR 估计的影响。我们的研究结果表明，季风期间气溶胶吸收最高，而冬季最低。由于气溶胶引起的大气显着变暖是由于表面的大量冷却造成的。在有限或多个波长下测量的气溶胶的柱状特性会产生相似的 ARF 和 HR 估计值，前提是使用跨季节的埃指数考虑光谱依赖性。然而，气溶胶消光的垂直剖面，以及沿大气柱的恒定单散射反照率 （SSA） 与实际的 SSA 剖面，导致 ARF 和 HRs 的显着差异，特别是在季风前和季风期间。与垂直分布相比，使用柱状特性时，自由对流层气溶胶的吸收被低估了，而边界层的吸收被高估了（> 10 Wm-2）。大气层间气溶胶类型的异质性显著影响了气溶胶的吸收，突出了准确垂直分布信息的重要性。 通过垂直分布获得的 HR 剖面反映了气溶胶消光的结构，而使用柱状特性估计的 HR 剖面会导致更平滑的剖面，无法捕获高度梯度。对于定义气溶胶特性的所有情景，在季风季节，气溶胶诱导的 HR 在边界层和自由对流层内都较高。这些发现强调了对气溶胶特性进行实际垂直剖面测量以量化气溶胶辐射相互作用的必要性。