Cloud-Climate Feedbacks due to Extra-Tropical Clouds Systems

本研究的主要目标是通过提高我们对云反馈效应和气溶胶-云相互作用的理解来减少气候变化预测的不确定性。该提案侧重于太平洋的热带云系，这是造成全球平均净云作用力为负的主要因素之一，并审查其在全球和北美气候变化中的作用。它将调查气溶胶的作用，特别是来自亚洲的灰尘和烟尘，以及调节太平洋上空云层的大尺度动力学。由于热带云系统由液态云和冰相云组成，拟议的研究将为气候变化研究开辟新的途径。本研究由两部分组成：一.气溶胶和云强迫和气溶胶云参数化： PI将估计大气辐射加热的垂直分布（或冷却）和表面变暗由于气溶胶，重点是灰尘和煤烟的混合物;云辐射强迫相同;提供输入人为和可能的生物云凝结核（CCN）的低和高云在区域尺度;建立一个区域模式，对气溶胶、云、化学和天气尺度动力学之间的相互作用进行明确的参数化。 本研究分为三个部分：A.建立气溶胶-云-动力学-辐射强迫综合观测数据集。这些数据将包括来自实地项目的观测，包括高空研究飞机数据、卫星和地面数据; B。估算云和气溶胶辐射强迫的三维结构;以及C.开发一个气溶胶-云-化学-传输-辐射模型，以解释观测到的场和强迫。气候影响研究：利用A部分的资料和模式方案，进行下列影响研究：烟尘远距离输送对太平洋和北太平洋的影响;美国气溶胶负荷，太平洋和北美上空的气溶胶和云辐射强迫;气溶胶和云强迫对太平洋海表面温度趋势和北美气候的影响;太平洋气溶胶云对过去和未来气候趋势的反馈影响。 这部分将使用美国国家大气研究中心（NCAR）的气候模式来估计气候变化的影响和气候反馈。更广泛的影响。 这项研究将产生关于太平洋上空气溶胶和云强迫的新的综合三维数据集。由于它将以观测为基础，它将非常有助于验证大气环流模式对气溶胶和云对气候影响的处理。强迫估计和气候影响研究将用于国家和国际人类对气候影响的评估。与东亚科学家的合作将对获得亚洲地区的可靠数据具有重要价值。最后，参与该项目的学生和博士后将有一个独特的机会接触具有挑战性的新研究途径，并参与国际合作。

SummaryThe main goal of this research is to reduce the uncertainty in climate change predictions by improving our understanding of cloud feedback effects and aerosol-cloud interactions in liquid as well as ice phase clouds. The proposal focuses on the extra tropical cloud systems of the Pacific Ocean, one of the major contributors to the negative global mean net cloud forcing, and examines its role in global and in North American climate change. It will investigate the role of aerosols, particularly dust and soot from Asia, and large scale dynamics in regulating cloud albedo over the Pacific Ocean. Since the extra tropical cloud systems consist of liquid as well as ice phase clouds, the proposed research will open new avenues of research in climate change. The research consists of two components: I. Aerosol and Cloud forcing and aerosol-cloud parameterization: The PI will estimate the vertical distribution of atmospheric radiative heating (or cooling) and surface dimming due to aerosols with a focus on dust-soot mixtures; same for cloud radiative forcing; provide input for anthropogenic and possibly biogenic cloud condensation nuclei (CCN) for both low and high clouds on regional scales; develop a regional model with explicit parameterizations for interactions between aerosols, clouds, chemistry and synoptic scale dynamics. The research consists of three parts: A. creating an integrated observational data set of aerosol-cloud-dynamics-radiative forcing. The data will include observations from field projects, including high altitude research aircraft data, satellite and surface data; B. estimating the 3-D structure of the radiative forcing of clouds and aerosols; and, C. developing an aerosol-cloud-chemical-transport-radiation model that accounts for the observed fields and forcing.II. Climate Impact Studies: Using the data and model schemes developed under Part A, conduct the following impact studies: the effect of long range transport of soot and dust on the Pacific and N. American aerosol loadings, and aerosol and cloud radiative forcing over the Pacific and N America; the effect of aerosol and cloud forcing on Pacific sea surface temperature trends and N American climate; and, the feedback effects of Pacific aerosol-clouds on the past and future climate trends. This part will employ National Center for Atmospheric Research (NCAR) climate models for estimating the impact on climate change and climate feedback. Broader Impacts. The research will generate new integrated 3-D data sets on aerosol and cloud forcing over the Pacific Ocean. Since it will be observationally based, it will be of great use for validating general circulation models' treatment of aerosol and cloud impacts on climate. The forcing estimates and climate impact studies will be used in national and international assessments of human impact on climate. The collaborations with East Asian scientists will be of great value for obtaining reliable data for the Asian region. Lastly, the students and post docs involved in the project will have a unique opportunity to get exposed to a challenging new avenue of research and participate in international collaborations.