UK ICE-D

这项研究的目标是确定沙漠尘埃如何影响对流云和层状云中冰粒的成核以及随后的云的降水和冰川作用的发展。尘埃被认为是地球系统中的关键气溶胶颗粒，主要是因为尘埃颗粒本身以及在从其来源输送时发生化学和可能生物改性的颗粒被认为是全球意义上最重要的冰核，并且因为尘埃颗粒被输送到地球仪的许多地方。从气溶胶粒子的分布预测云中冰粒子的初始和随后的演变是大气科学中最重要的问题之一。这对于NERC的高级别战略目标"了解和预测我们的星球如何运作“至关重要，因为缺乏对这些过程的了解导致全球模型处理辐射与冰和混合相云的相互作用以及降水发展的方式不确定。它们还造成数值天气预报模型的不确定性，而数值天气预报模型与NERC战略目标"抵御环境危害“有关。这项拟议中的研究旨在通过测量靠近世界上最大的沙漠灰尘来源之一的气溶胶和云粒子来解决这个问题。测量很难，这就是为什么以前从未在该地区进行过如此详细的测量。现在可以做到这一点，因为这些仪器能够确定气溶胶粒子的化学和物理特性，飞机云物理仪器可以探测到小冰粒，还有一个移动的双极化雷达。英国云中冰实验-尘埃（英国ICE-D）是美国-英国飞机和地面项目的一部分，该项目将于2015年（主要是英国）和2016年（主要是美国）在非洲塞内加尔海岸外的佛得角举行。将在云周围的环境中进行测量，以确定气溶胶粒子及其作为冰核和云凝结核的能力，并在云内确定粒子对云特性的影响。对流云将被优先测量，但层状云也将成为目标。当适当的高度上存在高浓度的灰尘和几乎没有灰尘时，将进行观测。美国和英国飞机的可用性无意中提供了一个独特的机会，以最大限度地提高云的抽样统计。地点和时间是从气候学研究中选择的，因为灰尘浓度通常很大，对流和层状云也经常发生。此外，该区域的对流云也很重要，因为它们可以形成云团，导致热带大西洋的风暴和飓风，具体而言，联合王国ICE-D将在有尘和无尘的日子测量以下内容：* 云滴、过冷雨滴、初冰粒及随飞机发展的冰和降水粒子;* 过冷雨滴的高度、首次降水回波的位置和时间，以及雷达观测到的径向气流;* 云的热力学和动力学以及它们与飞机和在某种程度上与雷达的环境。模型结果将与初始温度和增长和发展速率的观测结果进行比较。从气候到区域预报模型到明确的云物理过程模型等一系列模型将被用作预报工具和解释数据以及制定或改进参数化的工具。

The goal of this research is to determine how desert dust affects the nucleation of ice particles in convective and layer clouds and the subsequent development of precipitation and glaciation of the clouds. Dust is believed to be a critical aerosol particle in the Earth system mainly because the dust particles themselves, and particles that are chemically and possibly biologically modified as they are transported from their source, are believed to be the most important ice nuclei in a global sense and because dust particles are transported to many parts of the globe. Predicting the initiation and subsequent evolution of thesize distribution of ice particles in clouds from a distribution of aerosol particles is one of the most important problems in atmospheric science. It is fundamental to the NERC high-level strategy objective ``Understand and predict how our planet works'', because the lack of understanding of the processes causes uncertainty in the way global models treat the interaction of radiation with ice and mixed-phase clouds and the development of precipitation. They also cause uncertainty in Numerical Weather Prediction (NWP) models, which is concerned with the NERC strategy objective ``Resilience to environmentalhazards''. The proposed research aims to tackle this problem by making measurements of aerosols and cloud particles close to one of the largest sources of desert dust in the world. The measurements are difficult to make, which is why such detailed measurements have never been made in this region before. It is possible to do this now because the instruments are capable of determining the chemical and physical properties of aerosol particles, the aircraft cloud physics instruments can detect small ice particles, and there is a mobile dual-polarisation radar. The UK Ice in Clouds Experiment -- Dust (UK ICE-D) is part of the US-UK aircraft and ground-based project based in Cape Verde off the coast of Senegal, Africa to be held in 2015 (mainly UK) and 2016 (mainly US). Measurements will be made in the environment around the clouds to characterise the aerosol particles and their ability to act as ice nuclei and cloud condensation nuclei, and within the clouds to determine the influence of the particles on the cloud properties. Convective clouds will be measured as a priority, but layer clouds will also be targeted. Observations will be made when dust is present in high concentrations at appropriate altitudes and when almost no dust ispresent. The availability of the US and UK aircraft has inadvertently provided a unique opportunity to maximise the sampling statistics of the clouds. The location and time was selected from climatology studies because dust concentrations are often large and convective and layer clouds also occur frequently. In addition, the convective clouds in the region are known to be important since they can form clusters that lead to storms and hurricanes in the Tropical Atlantic.Specifically, UK ICE-D will make measurements on days with and without the presence of dust of the following:* Aerosol particles on the ground with the instruments in the aerosol container at Cape Verde and with the BAe 146 aircraft;* Cloud droplets, supercooled raindrops, the first ice particles and development of ice and precipitation particles with the aircraft;* The altitudes of the supercooled raindrops, the location and time of the first precipitation echoes, and the radial air motions using the radar;* The thermodynamics and dynamics of the clouds and their environment with the aircraft and to some extent the radar.Model results will be compared with the observations of the initiation temperatures and rates of growth and development. A spectrum of models ranging from climate through regional forecast models to explicit cloud physics process-based models, will be used as forecasting tools and as tools to interpret the data and to develop or improve parametrizations.