首页|三参数冰相云微物理方案在CIESM模式中的应用

三参数冰相云微物理方案在CIESM模式中的应用

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由于云的时空尺度非常宽广,云微物理参数化方案一直是气候模式中的薄弱环节.本文借鉴中尺度模式云微物理方案从双参数向三参数扩展的思路方法,发展了联合地球系统模式(Community Integrated Earth System Model,CIESM)三参数冰相云微物理方案,弥补了默认双参数方案不能预报冰晶粒径分布谱形参数(μ)的不足,进而分析了双、三参数方案对气候模拟的影响.模拟结果表明,相较于双参数方案(μ为0),三参数方案预报得出的μ更为合理,其在垂直分布上整体呈现出"高层小低层大"的特点,高层的低值主要是由于冰晶核化以及较大的冰晶粒子沉降后粒子之间相互混合导致的,而低层的高值主要是由于冰晶粒子在沉降过程中的粒子分选机制导致的.与双、三参数方案中∥的差异相呼应,模式模拟的气候平均态出现明显差异,其中三参数方案模拟的总云云量、低云云量、中云云量和总降水相较于双参数方案更接近观测结果,高云云量的误差增大.其中总降水的改进主要是由于高云云量的增加,大气稳定度增加,对流性降水减少.此外,还调整了相关参数,以改善模式对辐射的模拟能力.总之,本文在全球气候模式中评估了双、三参数方案对于模拟气候平均态的不同影响,为气候模式中云微物理方案的发展改进提供了一定的参考意义.
Application of triple-moment ice-phase cloud microphysics scheme in the CIESM model
Clouds cover approximately 2/3 of the Earth's surface and play a vital role in the radiation budget of the Earth-atmosphere system and the global water cycle.Since the scale of cloud microphysical processes is often much smaller than the grid scale of climate models,climate models rely on parameterizations to represent cloud microphysical processes which contribute significant uncertainties in climate model results.Improving the description of cloud microphysical processes is critical for climate models.Currently,most commonly-used climate models employ single or double-moment microphysics schemes.Inspired by improved results from triple-moment schemes in mesoscale models,a triple-moment ice-phase cloud microphysics scheme was developed for the Community Integrated Earth System Model(CIESM)in this study.This advancement addressed the limitation of the default double-moment scheme in predicting the shape parameter(μ)of the ice crystal size distribution.The impacts of both the double-and triple-moment schemes on climate simulations were analyzed in the study,and the underlying physical mechanisms were explored.The simulation results indicated that,compared to the double-moment scheme(μ=0),the triple-moment scheme provided a more reasonable prediction of μ.Overall,it exhibited a vertical distribution characterized by"lower values in the upper layers and higher values in the lower layers".The low values in the upper layers were primarily due to the nucleation of ice crystals and intermixing of ice crystals during sedimentation.On the other hand,the high values in the lower layers were mainly attributed to the size sorting of ice crystals.In correspondence with the differences in μ between the double-and triple-moment schemes,noticeable disparities emerged in the simulated climatological states.Compared to the default double-moment scheme,the triple-moment scheme significantly improved the simulation of low,middle,and total cloud fraction,as well as the total precipitation against observations.However,the triple-moment scheme led to a notable increase in high cloud fraction.The prominent increase in middle and high cloud fraction was primarily attributed to the triple-moment scheme narrowing the ice crystal particle spectrum by predicting μ.This narrowing weakened the autoconversion of ice crystals into snow,enhanced the growth process of ice crystal deposition,and ultimately resulted in a substantial increase in the mass concentration of ice crystals and ice cloud fraction.And the improvement in total precipitation was mainly due to the increase in high cloud fraction,leading to a greater atmospheric stability and consequently a reduction in convective precipitation.The cloud radiative forcing simulated by the triple-moment scheme captured the overall characteristics of the observational data.The new scheme alleviated the negative bias in longwave cloud forcing simulated by the double-moment scheme in mid-latitude regions.In summary,this study implemented a triple-moment ice-phase cloud microphysics scheme in the CIESM model and quantitatively evaluated the distinct impacts of the double-and triple-moment schemes on climatological states.These findings provide valuable insights for the improvement of cloud microphysics schemes in climate models,helping to understand climate change and cloud feedback processes to enhance the model's ability to simulate clouds.

the ice crystal spectral shape parametertriple-moment schememicrophysicsclimate model

贺欣、陆春松、史湘军、朱磊、张文韬、李特、李君俊、吴尚、徐晓齐

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南京信息工程大学,中国气象局气溶胶与云降水重点开放实验室/气象灾害预报预警与评估协同创新中心,南京 210044

南京信息工程大学大气科学学院,南京 210044

兰州大学大气科学学院,甘肃省气候资源与防灾减灾重点实验室,兰州 730000

江苏省气象台,南京 210008

南京气象科技创新研究院,南京 210008

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冰晶谱形参数 三参数方案 微物理 气候模式

国家杰出青年科学基金国家重点研发计划国家自然科学基金国家自然科学基金2023年江苏省研究生科研创新计划四川省自然科学基金中央高校基本科研业务费

423255032019YFA06068034177509542205080KYCX23_13192023YFS0442J2022-037

2024

10.1360/TB-2023-0921

科学通报
中国科学院国家自然科学基金委员会

科学通报

CSTPCD北大核心
影响因子：1.269
ISSN：0023-074X
年,卷(期)：2024.69(17)