Ice formation in clouds and the implications for climate

云中冰的形成及其对气候的影响

• 批准号: 2748901
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2748901
• 关键词: Ice; formation; clouds; implications; climate

This project combines weather-scale and climate modelling with satellite data to understand ice formation in clouds and the effect on future climate.Climate models are very poor at representing the mixture of ice and supercooled water drops in clouds. Models therefore diverge dramatically in the amounts of ice and water that they simulate and the agreement with satellite observations is extremely poor for many models. The formation of ice crystals in a cloud reduces cloud reflectivity and can even result in the complete removal of cloud water through strong precipitation, leading to substantial reductions in cloud coverage. The huge range of model predictions is partly due to inadequate (and sometimes non-physical) representations of ice-related processes in models, with most models even neglecting any representation of the particles that trigger ice formation - ice-nucleating particles (INPs).Ice formation is a critical process in determining the magnitude of cloud feedbacks (how much a change in cloud properties in a future climate could alter the climate). It therefore represents a major uncertainty in climate projections. Two key factors determining the strength of the feedback for mixed-phase clouds are the amount of ice in present-day clouds and the response of this ice content to increases in temperature or other alterations in the meteorological conditions. This project will use satellite observations to understand and then constrain these factors in the UK Earth System Model (UKESM).

该项目将天气尺度和气候模拟与卫星数据相结合，以了解云中冰的形成及其对未来气候的影响，气候模型在表示云中冰和过冷水滴的混合物方面非常差。因此，模型在它们模拟的冰和水的数量上存在显着差异，并且许多模型与卫星观测的一致性非常差。云中冰晶的形成降低了云的反射率，甚至可以通过强降水完全去除云中的水，导致云覆盖范围的大幅减少。模式预测的范围如此之大，部分是由于模式中对冰相关过程的描述不够充分（有时是非物理的），大多数模式甚至忽略了触发冰形成的粒子--冰成核粒子（INPs）。冰的形成是决定云反馈大小的关键过程（未来气候中云特性的变化会改变气候的程度）。因此，它是气候预测中的一个重大不确定性。决定混合相云反馈强度的两个关键因素是当今云中的冰量以及冰含量对温度升高或气象条件其他变化的响应。该项目将利用卫星观测来了解这些因素，然后将其限制在英国地球系统模型（UKESM）中。