| Title | Microphysical processes producing high ice water contents (HIWCs) in tropical convective clouds during the HAIC-HIWC field campaign: dominant role of secondary ice production |
| Authors | Huang, Yongjie Wu, Wei McFarquhar, Greg M. Xue, Ming Morrison, Hugh Milbrandt, Jason Korolev, Alexei, V Hu, Yachao Qu, Zhipeng Wolde, Mengistu Cuong Nguyen Schwarzenboeck, Alfons Heckman, Ivan |
| Affiliation | Univ Oklahoma, Ctr Anal & Predict Storms, Norman, OK 73019 USA Univ Oklahoma, Cooperat Inst Severe & High Impact Weather Res &, Norman, OK 73019 USA Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA Natl Ctr Atmospher Res, Mesoscale & Microscale Meteorol Lab, POB 3000, Boulder, CO 80307 USA Environm & Climate Change Canada, Dorval, PQ, Canada Environm & Climate Change Canada, Toronto, ON, Canada Peking Univ, Sch Phys, Dept Atmospher & Ocean Sci, Beijing, Peoples R China Natl Res Council Canada, Ottawa, ON, Canada Univ Clermont Auvergne, CNRS, UMR 6016, Lab Meteor Phys, Clermont Ferrand, France |
| Keywords | LOW RADAR REFLECTIVITY IN-SITU PART I DEEP CONVECTION SQUALL-LINE PARAMETERIZATION NUCLEATION BULK PARTICLES FRAGMENTATION |
| Issue Date | 22-Feb-2022 |
| Publisher | ATMOSPHERIC CHEMISTRY AND PHYSICS |
| Abstract | High ice water content (HIWC) regions in tropical deep convective clouds, composed of high concentrations of small ice crystals, were not reproduced by Weather Research and Forecasting (WRF) model simulations at 1 km horizontal grid spacing using four different bulk microphysics schemes (i.e., the WRF single-moment 6-class microphysics scheme (WSM6), the Morrison scheme and the Predicted Particle Properties (P3) scheme with one- and two-ice options) for conditions encountered during the High Altitude Ice Crystals (HAIC) and HIWC experiment. Instead, overestimates of radar reflectivity and underestimates of ice number concentrations were realized. To explore formation mechanisms for large numbers of small ice crystals in tropical convection, a series of quasi-idealized WRF simulations varying the model resolution, aerosol profile, and representation of secondary ice production (SIP) processes are conducted based on an observed radiosonde released at Cayenne during the HAIC-HIWC field campaign. The P3 two-ice category configuration, which has two "free" ice categories to represent all ice-phase hydrometeors, is used. Regardless of the horizontal grid spacing or aerosol profile used, without including SIP processes the model produces total ice number concentrations about 2 orders of magnitude less than observed at -10 degrees C and about an order of magnitude less than observed at -30 degrees C but slightly overestimates the total ice number concentrations at -45 degrees C. Three simulations including one of three SIP mechanisms separately (i.e., the Hallett-Mossop mechanism, fragmentation during ice-ice collisions, and shattering of freezing droplets) also do not replicate observed HIWCs, with the results of the simulation including shattering of freezing droplets most closely resembling the observations. The simulation including all three SIP processes produces HIWC regions at all temperature levels, remarkably consistent with the observations in terms of ice number concentrations and radar reflectivity, which is not replicated using the original P3 two-ice category configuration. This simulation shows that primary ice production plays a key role in generating HIWC regions at temperatures <-40 degrees C, shattering of freezing droplets dominates ice particle production in HIWC regions at temperatures between -15 and 0 degrees C during the early stage of convection, and fragmentation during ice-ice collisions dominates at temperatures between -15 and 0 degrees C during the later stage of convection and at temperatures between -40 and -20 degrees C over the whole convection period. This study confirms the dominant role of SIP processes in the formation of numerous small crystals in HIWC regions. |
| URI | http://hdl.handle.net/20.500.11897/638552 |
| ISSN | 1680-7316 |
| DOI | 10.5194/acp-22-2365-2022 |
| Indexed | SCI(E) |
| Appears in Collections: | 物理学院 |
