Evolution of tropical deep-convective clouds derived from ground-based imaging spectroradiometer measurements

具体地说，该项目将通过成像光谱辐射计系统对云侧反射辐射的地面测量，得出热带深对流云微观物理性质的垂直分布。这一总体目标是描述在地球气候系统中发挥重要作用的DCC的垂直演化特征。将根据气溶胶和热力学条件对云粒增长的影响来研究云的演变。计划中的测量将在新的亚马逊高塔天文台(ATTO)上进行，该天文台高320米，位于亚马逊盆地靠近赤道的地方。ATTO配备了测量微气象和大气化学变量以及气溶胶特性的仪器。它提供了理想的观测条件，季节晴朗(雨季和旱季)，在气溶胶颗粒浓度和类型高度可变的环境中每天都会发生DCC。新的成像光谱辐射计系统SPIRAS(光谱成像辐射系统)将通过基于三维辐射传输模拟的改进方法，获得高时间和空间分辨率的热力学相和云有效半径的垂直剖面。通过这种方式，将识别表征液滴生长的垂直区(扩散、合并、混合相和冰化)。红外相机和扫描去偏振激光雷达的辅助测量将被用来估计观测到的云元素的高度和温度。此外，激光雷达的偏振测量将支持热力学相的恢复，这对识别相变非常重要。通过获得的数据，我们将验证卫星观测的反演方法的假设(有效粒子半径为保守的云属性)，以得出微物理剖面。

Specifically the project will derive the vertical profile of microphysical properties of tropical deep-convective clouds (DCC) from ground-based measurements of reflected radiation from cloud sides by an imaging spectroradiometer system. This general objective is to characterize the vertical evolution of DCCs, which play an important role in the Earths climate system. The evolution will be studied with respect to the impact of aerosol and thermodynamic conditions on the cloud particle growth. The planned measurements will be performed on the new Amazonian Tall Tower Observatory (ATTO), of 320 m height situated in the Amazon Basin near the equator. ATTO is equipped with instruments to measure micrometeorological and atmospheric chemical variables, as well as aerosol properties. It provides ideal observation conditions with clear seasons (wet and dry season), and daily occurrence of DCCs in a highly variable environment with respect to concentrations and types of aerosol particles. The new imaging spectroradiometer system, SPIRAS (SPectral Imaging Radiation System), will be used to derive vertical profiles of thermodynamic phase and cloud effective radius with high temporal and spatial resolution by means of adapted methods based on three-dimensional radiative transfer simulations. In this way vertical zones characterizing the droplet growth (diffusion, coalescence, mixed-phase, and glaciation) will be identified. Auxiliary measurements by an infrared camera and a scanning depolarization Lidar will be used to estimate the height and the temperature of the observed cloud element. Additionally, polarization measurements by Lidar will support the retrieval of the thermodynamic phase which is important to identify the phase transition. By means of the data obtained we will validate assumptions (effective particle radius as conservative cloud property) of retrieval methods for satellite-based observations to derive microphysical profiles.