SGER:Humidity and Ice Supersaturation Observations at South Pole Station

尽管卷云的性质被认为是大气辐射平衡中的一个很大的不确定性，但关于冰核和冰云形成的确切机制的几个方面仍然没有得到解决。在气候模型中准确表示这些系统的微物理对于模拟它们的辐射强迫以及确定对流层上层的人为粒子是否可能影响冰云特性至关重要。对卷云微物理的现场研究通常只能由限制在中纬度或热带地区的相对较高高度的飞机进行。这对观测时间和仪器有效负载造成了限制。飞机测量还可能受到仪器表面高撞击速度和加热率等额外复杂因素的影响，从而导致环境温度和湿度读数的不确定性。这一小笔探索性研究补助金(SGER)支持PI及时利用之前资助的、尚未执行的实地活动，调查新型湿度传感器的使用，以便更好地了解在唯一可访问的环境，即高海拔南极大气中的冰核和冰晶生长。该建议符合SGER的标准，即既有风险元素(即不确定或不可预见的工程问题)，又有潜在的高回报(即，允许在难以访问的环境系统中跟踪冰晶的时间变化的独特数据集)。该建议符合额外的SGER标准，即代表对独特的、预先存在的现场活动测量机会的快速反应。广泛影响：预期数据集的应用，以及父项目(OPP-0337876)收集的辅助数据，将有助于更好地理解冰的微物理、卷云的辐射强迫，并提高气候模拟工作的保真度。

Several aspects of the exact mechanisms of ice nucleation and ice cloud formation remain unsettled despite, for example, the properties of cirrus clouds being recognized as a large uncertainty in the radiative balance of the atmosphere. Accurate representation of the microphysics of these systems in climate models is crucial to simulation of their radiative forcing, and also to determining whether anthropogenic particles in the upper troposphere may be affecting ice cloud properties. In situ studies of the microphysics of cirrus clouds are normally accessible only by relatively high altitude aircraft restricted to the mid-latitudes, or the tropics. This poses limits on observation time and instrumentation payloads. Aircraft measurements may also be subject to additional complications of high impaction velocities and heating rates on instrument surfaces leading to uncertainties in ambient temperature and humidity readings. This Small Grant for Exploratory Research (SGER) supports the PI to take a timely opportunity of a previously funded, not yet executed field campaign, to investigate the use of a new humidity sensor in order to better understand the ice nucleation and ice crystal growth at a uniquely accessible environment, namely the high altitude South Pole atmosphere.The proposal meets the SGER criteria of having both an element of risk (i.e. uncertain or unforseen engineering issues) but a potentially high pay-off (i.e. a unique data set allowing temporal change of ice crystals to be followed in a difficult to access environmental system). The proposal meets an additional SGER criterion of representing a quick response to a unique, pre-existing field campaign measurement opportunity.Broader impacts: Applications of the expected data set, along with the ancillary data collected by the parent project (OPP-0337876) will contribute to better understanding of ice microphysics, radiative forcing of cirrus clouds, and improve the fidelity of climate modeling efforts.