A SIMPLE, INEXPENSIVE, LIGHT WEIGHT, ROBUST AEROSOL OPTICAL SCATTER CELL.

政府间气候变化专门委员会在2007年的第四次评估报告中指出，人为气溶胶“仍然是辐射强迫的主要不确定性因素”。更多的气溶胶应该会将更多的阳光反射到太空中，并倾向于冷却气候，或者，如果气溶胶含有黑碳，它们可能会加热空气，导致云层蒸发，而更少的云层会反射更少的阳光到太空。更多的气溶胶可能会导致云中有更多但更小的水云滴，使它们看起来更白，并将更多的阳光反射回太空，此外，如果更小的水滴不太可能聚集、形成雨和消散，那么云的寿命可能会延长。对于冰云来说，情况甚至更加复杂和不确定。当温度降至冰点以下时，大多数水滴仍以液体形式存在，并处于过冷状态；只有极少数气溶胶粒子具有冰核的特性，并促进冰冻。人为气溶胶对冰核数量的影响基本上是未知的。此外，气溶胶本身可能由有害健康的污染物组成，因此，如果我们要了解并改进预测污染水平的模型，我们需要更多地了解它们的来源，它们是如何在大气中传输的，以及它们如何从空气中去除。为了提高我们对大气中气溶胶的了解，我们需要更好地测量它们的分布，以及这种分布如何随不同天气模式的变化而变化，以及气溶胶如何影响云的特性。特别是，我们需要能够在各种平台和极端条件下进行测量：例如，在大风条件下靠近海面。尽管可用的仪器范围很广，但适合研究粒子通量的时间响应仪器(~10赫兹)太大、太贵，而足迹较小的仪器又很昂贵，时间响应太慢。为了解决这些问题，利兹大学的研究人员开发了一种体积小、重量轻、反应快的光学光谱仪，它参与了各种各样的项目，无异于它的成功和普及。然而，必须使用商业上可获得的散射电池，事实证明，这种电池与制造过程中使用的部件过于复杂，现在已经过时；此外，制造商要求达成惩罚性许可协议，这意味着不能进一步开发电池，越来越多的购买扣环单元的请求被拒绝。最初开发CLAP的团队一直在研究一种新的、经过极大改进的散射室，在此基础上，可以开发出新一代快速响应、小而轻的气溶胶光谱仪，以满足极端部署场景、个人采样器或尺寸和重量成问题的平台中对仪器的需求。这个新的单元目前处于技术准备级别(TRL)3，要求提供资金以使该单元发展到TRL 4或更高。

The Intergovernmental Panel on Climate Change, in its fourth assessment report in 2007, states that anthropogenic aerosols 'remain the dominant uncertainty in radiative forcing'. More aerosols should reflect more sunlight out to space and tend to cool the climate, or alternatively, if the aerosols contain black carbon they may heat the air and cause clouds to evaporate, and less cloud would reflect less sunlight to space. More aerosols could lead to clouds having more but smaller water cloud droplets so they would appear 'whiter' and reflect more sunshine back to space, in addition, if the smaller droplets are less likely to coalesce and form rain and dissipate, so the cloud lifetime may increase. For ice clouds the situation is even more complex and uncertain. When the temperature falls below freezing most of the water drops remain as liquid and are 'supercooled'; only a very few aerosol particles have the property of being an 'ice nuclei' and promoting freezing. The effect of anthropogenic aerosols on the number of ice nuclei is essentially unknown. In addition aerosols themselves can be composed of pollutants which are deleterious to health, and so we need to know more about their sources, how they are transported around the atmosphere and how they are removed from the air, if we are to understand and consequently improve models forecasting pollution levels. To improve our knowledge of aerosols in the atmosphere we need better measurements of their distribution and how this changes as a function of the different weather patterns and how the aerosols influence the cloud properties. In particular we need to be able to make measurements form a wide range of platforms and in extreme conditions: for example close to sea surface in high wind conditions. Although the range of instrumentation available is wide those with a temporal response suitable for the investigation of particle fluxes (~10Hz) are too large and expensive, while those with a smaller foot print are again expensive and have too slow a temporal response. To address these problems researchers at the University of Leeds developed a small, light weight, fast response optical spectrometer, CLASP, and its participation in a wide variety of projects is tantamount to it success and popularity. Use had to be made, however, of a commercially available scatter cell that has proven overly complex with components used in its fabrication that are now obsolete; in addition the punitive licence agreement required form the manufacturer means that no further cell development can occur and the increasing number of requests to purchase a CLASP unit refused. The team that originally developed CLASP have been working on a new and vastly improved scatter cell from which a new generation of fast response, small, light weight aerosol spectrometers can be developed to address the need for instrumentation that can be used in extreme deployment scenarios, in personal samplers, or on platforms where size and weight is an issue. This new cell is currently at Technology Readiness Level (TRL) 3 and funding is requested to progress this cell to TRL 4 and beyond.