A microfluidic device for quantification of atmospheric ice-nucleating particles (FluidIce)

一小部分大气气溶胶粒子在云中形成冰，对气候有不成比例的影响。这些冰核粒子的量化是减少与地球仪周围云相关的气候不确定性的关键，从热带的深层对流到海洋中高纬度的边界层云。然而，大气中冰成核粒子的浓度、源、汇、输运和活动都很难确定。一个主要的限制是缺乏能够测量冰成核颗粒的仪器。我们之前已经开发了一个原型微流体平台，用于在Murray的欧洲研究理事会奖学金中量化大气冰成核颗粒，但它的吞吐量和自动化受到仪器和数据处理挑战的限制。在这里，我们建议采取LOC-NIPI远远超出了默里的ERC补助金中所设想的，并大大提高其对大气冰成核粒子的量化的实用性。在FluidIce中，我们将用一个更简单的LED光电二极管检测器取代数据饥渴（和限制）的高速摄像机，再加上我们新的冷冻-解冻液滴分选设备。这一相对温和的投资将使我们能够大大加快样本吞吐量，从而为其他项目增加大量价值，例如M-Phase（NERC拨款，专注于云相反馈，作为CloudSense计划的一部分）和WesCon（英国气象局资助的飞机项目，研究英国的高影响对流）。FluidIce的遗产将使未来的现场和实验室项目中冰成核颗粒浓度的常规量化降至~-35 C成为可能。FluidIce还将LOC-NIPI推向我们的长期目标，即能够连续监测冰成核颗粒光谱的全自动仪器，从取样到冷冻分析。

A small fraction of atmospheric aerosol particles that nucleate ice in clouds have a disproportionate effect on climate. Quantification of these ice-nucleating particles is key to reducing climate uncertainties associated with clouds around the globe, from deep convection in the tropics to boundary layer clouds in the oceanic mid- to high-latitudes. However, the atmospheric concentration, sources, sinks, transport and activity of ice-nucleating particles are all poorly defined. A major limitation is the lack of instrumentation capable of measuring ice-nucleating particles. We have previously developed a prototype microfluidic platform for quantifying atmospheric ice-nucleating particles in Murray's European Research Council fellowship, but it's throughput and automation are limited by both instrumental and data processing challenges. Here we propose to take LOC-NIPI far beyond what was envisaged in Murray's ERC grant and to vastly improve it utility for the quantification of atmospheric ice-nucleating particles.In FluidIce we will replace the data-hungry (and limiting) high speed camera with a much simpler LED-Photodiode detector coupled with our new frozen-unfrozen droplet sorting device. This relatively modest investment will allow us to greatly speed up sample throughput and therefore add a great deal of value to other projects, such as M-Phase (a NERC grant focused on the cloud-phase feedback as part of the CloudSense programme) and WesCon (a Met Office funded aircraft project looking at high-impact convection in the UK). The legacy of FluidIce will make the routine quantification of ice-nucleating particles concentrations down to ~-35 C possible in future field and laboratory projects. FluidIce also moves the LOC-NIPI towards our longer term goal of a fully automated instrument capable of continuous monitoring of ice-nucleating particle spectra, from sampling through to freezing analysis.