An Antarctic-Specific, New Generation Precipitation Model

南极特定的新一代降水模型

• 批准号: 0738055
• 负责人: Patrick Newell
• 金额: $ 27.3万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0738055&HistoricalAwards=false
• 关键词: Antarctic; Specific; New; Generation; Precipitation

The proposal seeks support for developing a new ionospheric particle precipitation model for the Southern polar cap. The most widely used precipitation model today is more than two decades old (Hardy et al., 1985, 1989); it was developed from a limited set of satellite data with extrapolation, where both the Northern and Southern polar cap crossings were combined together to increase statistics. This precipitation model has not been tested against global UV auroral images, and thus its operational effectiveness is undetermined. The model's main binning parameter (Kp index of planetary geomagnetic activity) implies that only less than half the variance in auroral power (i.e., power brought by precipitating particles into the ionosphere) can be predicted, even were binning ideal (which was not). Many advances have occurred since because the DMSP dataset has grown enormously over the last two decades. There are more than 60 satellite-years of data accumulated with vastly greater local time coverage (partly due to satellite orbit drifts). A solar cycle worth of NASA's POLAR spacecraft UV global auroral images are now available on-line, providing the ability to calibrate and validate instantaneous predictions of global auroral power. The proposed model will use specific functional fits (rather than wide bins) and optimized solar wind parameters. The new model will also probe basic space physics science problems; for example, although it is known that more precipitating energy flux occurs in darkness than in sunlight, little is known about the change in flux's spectral shape. The offset of Earth's magnetic dipole from the planet center has led to speculation about precipitation differences between the Northern and Southern hemispheres. Therefore, the present proposal is best suited to resolve this issue developing specifically the precipitation model over the Antarctic. This new precipitation model can be used as input to high-latitude upper atmospheric chemistry models, for estimating ionospheric conductivity, for determining the impact of space weather on operational systems, and much else.

该提案寻求支持为南极冰帽开发一个新的电离层粒子沉淀模式。今天使用最广泛的降水模型已有二十多年的历史(Hardy等人，1985,1989)；它是从一组有限的卫星数据外推发展而来的，其中北极和南方极地冰盖交叉被合并在一起，以增加统计数据。这一降水模型尚未针对全球紫外线极光图像进行测试，因此其运行效果尚不确定。该模型的主要入库参数(行星地磁活动的Kp指数)意味着，即使是理想的入库，也只能预测不到极光功率(即粒子沉入电离层带来的功率)变化的一半。自那以来取得了许多进展，因为DMSP数据集在过去20年里有了巨大的增长。有60多个卫星年的数据积累，当地时间的覆盖率要大得多(部分原因是卫星轨道漂移)。美国宇航局极地航天器紫外线全球极光图像相当于太阳周期，现在可以在线获取，提供校准和验证全球极光能量的瞬时预测的能力。建议的模型将使用特定的函数拟合(而不是宽箱)和优化的太阳风参数。新模型还将探索基本的空间物理科学问题；例如，尽管已知降水能量通量在黑暗中比在阳光下发生得更多，但人们对通量光谱形状的变化知之甚少。地球磁偶极子与行星中心的偏移导致了人们对南北半球降水差异的猜测。因此，本提案最适合于解决这一问题，特别是发展南极上空的降水模式。这一新的降水模型可用作高纬度高层大气化学模型的输入，用于估计电离层电导率，用于确定空间天气对业务系统的影响等。