Influences of Graupel Microphysics on CMA-GFS Simulation of Summer Regional Precipitation

The horizontal resolution of global numerical weather prediction models is continuously developing. However, due to the imperfect precipitation simulation/forecast of these models, the demand for considering riming particles in cloud microphysical schemes in these models is increasing. This study employed the latest versions of global atmospheric reanalysis data (ERA5), the satellite retrieval data of the Global Precipitation Observation Program (GPM),and station precipitation observations to explore the impacts of adding graupel to the cloud microphysical scheme in the China Meteorological Administration-Global Forecast System (CMA-GFS) on summer regional precipitation simulations in four Chinese climate zones. The results verify that the new graupel scheme can enable CMA-GFS to decently predict global graupel distribution, especially in tropical and midlatitude regions. The addition of graupel in the cloud microphysics increases the precipitation simulation in North China, while that in Southwest China is weakened and dispersed. Moreover, graupel scheme increases the precipitation simulations of almost all magnitudes.The increase in light rain is obvious, and the absolute value of heavy rain is strengthened. This may be because graupel quickly melts into rain after falling out of the zero-temperature layer due to its large mass and fast falling speed, increasing surface precipitation. In summary, the addition of graupel in the cloud microphysical scheme can improve CMA-GFS’s underestimation of strong precipitation.

Heterogeneousα-Diimine Nickel Catalysts with Improved Catalytic Performance in Ethylene Polymerization

Heterogenization can improve the thermal tolerance of olefin polymerization catalysts and result in good product morphology con-trol,which are two important parameters for industrial polyethylene production.In this work,α-diimine nickel catalysts bearing-OH or-ONa anchoring groups were designed and prepared.The anchoring groups can enable facile heterogenization of the cata-lysts on silica.The heterogeneous catalysts demonstrated enhanced thermal stabilities,along with high catalytic activity at 120℃(up to 5.5×10^(6)g·PE·mol·Ni^(-1)·h^(-1)).Furthermore,the heterogenization process results in the improvements of many other parame-ters,including polymer morphology control,catalytic activity(up to 1.9×10^(7)g·PE·mol·Ni^(-1)·h^(-1))and polyethylene molecular weight(Mn up to 2.3×10^(6)g·mol^(-1)).More importantly,the structure and properties of the polymer products can be controlled by catalyst structures,polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.

Simulation Study of Cloud Properties Affected by Heterogeneous Nucleation Using the GRAPES＿SCM during the TWP-ICE Campaign

This study used the Global/Regional Assimilation and PrEdiction System Single-Column Model(GRAPES_SCM)to simulate monsoon precipitation with deep convective cloud and associated cirrus during the Tropical Warm Pool International Cloud Experiment(TWP-ICE),especially during the active and suppressed monsoon periods.Four cases with different heterogeneous nucleation parameterizations were simulated by using the ensemble method.All simulations clearly separated the active and suppressed monsoon periods,and they reproduced the major characteristics of monsoonal cloud such as the total cloud hydrometeor mixing ratio distribution,and precipitation and radiation properties.The results showed that the number concentration production rate of different heterogeneous nucleation parameterizations varied substantially under the given temperature and water vapor mixing ratio.However,ice formation and precipitation during the monsoon period were affected only slightly by the different heterogeneous nucleation parameterizations.This study also captured clear competition between different ice formation processes.