Analysis of the Radiative Response of Clouds to El Nino/Southern Oscillation (ENSO) Climate Fluctuations

云反馈是地球气候的重要调节因素，因为太阳入射和出射长波辐射的变化预计将对云产生影响，而云的变化预计将对大气辐射产生进一步影响。这种反馈是气候模型对温室气体浓度从一个模型到另一个模型的温室气体浓度增加所导致的气温上升预测之间最显著的差异来源。然而，决定云反馈的符号和强度的物理和动力学还不是很清楚，而且很难在现实世界中测量这种反馈，并确定气候模式中的云反馈是否被准确地表示。在这个项目中，通过观测和模式输出来检验伴随着厄尔尼诺/南方涛动(ENSO)事件的云反馈，从而可以利用ENSO事件来评估云反馈的保真度，并且可以在现实世界的背景下更好地理解决定云反馈的因素。云反馈是通过卫星观测、再分析产品和气候模式确定的，并将重点放在确定哪些气象变量在确定反馈的符号和强度上。由于云反馈的重要性是气候模型预测由于温室气体浓度增加而导致地球温度升高程度的不确定的来源，这项工作具有更广泛的影响。此外，该工作还将支持和培养一名研究生，从而促进下一代科学家的发展。

Cloud feedbacks are an important regulator of Earth's climate, as changes in incoming solar and outgoing longwave radiation are expected to have an influence on clouds, and changes in clouds are expected to have further influences on atmospheric radiation. Such feedbacks are the most prominent source of differences between climate model projections of temperature increases due to increased greenhouse-gas concentrations from one model to another. However, the physics and dynamics which determine the sign and strength of cloud feedbacks are not well known, and it is difficult to measure such feedbacks in the real world and determine whether cloud feedbacks in climate models are represented accurately. In this project, cloud feedbacks accompanying El Nino/Southern Oscillation (ENSO) events are examined in observations and model output, so that ENSO events can be used to assess the fidelity of cloud feedbacks, and a better understanding of the factors determining cloud feedbacks can be achieved in a real-world context. Cloud feedbacks are determined from satellite observations, reanalysis products, and climate models, and attention is devoted to determining which meteorological variables are most important in determining the sign and strength of the feedback.The work has broader impacts due to the importance of cloud feedbacks as a source of uncertainty in climate model projections of the extent to which the Earth's temperature will increase due to increasing greenhouse gas concentrations. In addition, the work will support and train a graduate student, thereby promoting the next generation of scientists.