Comment on acp-2022-492

Abstract

<strong class="journal-contentHeaderColor">Abstract.</strong> The potential impacts of dust aerosols and atmospheric convective available potential energy (CAPE) on the vertical development of precipitating clouds in southeastern China (20–30<span class="inline-formula">^∘</span> N, 110–125<span class="inline-formula">^∘</span> E) in June, July, and August from 2000 to 2013 were studied using multisource observations. In southeastern China, heavy-dust conditions are coupled with strong northerly winds that transport air masses containing high concentrations of mineral dust particles, with cold temperatures, and with strong wind shear. This leads to weaker CAPE on dusty days compared with that on pristine days. Based on satellite observations, precipitating drops under dusty conditions grow faster in the middle atmospheric layers (with a temperature of between <span class="inline-formula">−5</span> and <span class="inline-formula">+</span>2 <span class="inline-formula">^∘</span>C) but slower in the upper and lower layers compared with their pristine counterparts. For a given precipitation top height (PTH), the precipitation rate under dusty conditions is lower in the upper layer but higher in the middle and lower layers. Moreover, the associated latent heating rate released by precipitation in the middle layer is higher. The precipitation top temperature (PTT) shows a fairly good linear relationship with the near-surface rain rate (NSRR): the linear regression slope between the PTT and NSRR is stable under dusty and pristine conditions. However, the PTT<span class="inline-formula">₀</span> (the PTT related to rain onset) at the onset of precipitation is highly affected by both the CAPE and aerosol conditions. On pristine days, a stronger CAPE facilitates the vertical development of precipitation and leads to a decrease in PTT<span class="inline-formula">₀</span>, at a rate of <span class="inline-formula">−0.65</span> <span class="inline-formula">^∘</span>C per 100 J kg<span class="inline-formula">^−1</span> of CAPE for deep convective precipitation (with a variation of 15 %) and at a rate of <span class="inline-formula">−0.41</span> <span class="inline-formula">^∘</span>C per 100 J kg<span class="inline-formula">^−1</span> of CAPE for stratiform precipitation (with variation of 12 %). After removing the impacts of CAPE on PTT, dust aerosols led to an increase in PTT<span class="inline-formula">₀</span>, at a rate of <span class="inline-formula">+</span>4.19 <span class="inline-formula">^∘</span>C per unit aerosol optical depth (AOD) for deep convective precipitation and at a rate of <span class="inline-formula">+</span>0.35 <span class="inline-formula">^∘</span>C per unit AOD for stratiform precipitation. This study showed clear evidence that meteorological conditions and aerosol conditions combine to impact the vertical development of precipitation clouds. A quantitative estimation of the sensitivity of PTT to CAPE and dust was also provided.