Journal Article
Atmospheric Chemistry and Physics, vol. 21, iss. 4, pp. 2363-2381, 2021
Authors
Yuwei Zhang, Jiwen Fan, Zhanqing Li, Daniel Rosenfeld
Abstract
Abstract. Aerosol–cloud interactions remain largely uncertain with respect to predicting their
impacts on weather and climate. Cloud microphysics parameterization is one
of the factors leading to large uncertainty. Here, we investigate the impacts
of anthropogenic aerosols on the convective intensity and precipitation of a
thunderstorm occurring on 19 June 2013 over Houston with the Chemistry
version of Weather Research and Forecast model (WRF-Chem) using the Morrison
two-moment bulk scheme and spectral bin microphysics (SBM) scheme. We find
that the SBM predicts a deep convective cloud that shows better agreement with
observations in terms of reflectivity and precipitation compared with the
Morrison bulk scheme that has been used in many weather and climate models.
With the SBM scheme, we see a significant invigoration effect on convective
intensity and precipitation by anthropogenic aerosols, mainly through
enhanced condensation latent heating. Such an effect is absent with
the Morrison two-moment bulk microphysics, mainly because the saturation
adjustment approach for droplet condensation and evaporation calculation
limits the enhancement by aerosols in (1) condensation latent heat by
removing the dependence of condensation on droplets and aerosols and (2) ice-related processes because the approach leads to stronger warm rain and
weaker ice processes than the explicit supersaturation approach.
