STAR-Light - A 1.4 GHz Scanning Thinned Array Radiometer for use on light aircraft in arctic land-surface hydrology

abstractopp - 0085176 - a.w。英格兰star - light -一种1.4 GHz扫描薄阵列辐射计，用于北极陆地表面水文研究的轻型飞机star - light将使水文学家能够将陆地-大气能量和水分输送过程的绘图模型扩展到极地附近的北极。在具有代表性和可接近的地点进行的北极能量平衡实验被用于开发陆面过程（LSP）模型，但是从这些地点推断到北极极地周围变化和混合的地形将需要模型校准和验证，这只能通过在从春季融化开始到秋季冻结结束的广泛区域的频繁观测来实现。一旦校准，这些区域模式要么作为改进的大气模式的下边界，要么作为综合区域水文模式的更可靠的要素。LSP模型的核心是对土壤、植被和雪中储存的水分的估计。这些估计的质量和模式预测的技巧可以通过吸收近每天对土壤上层几厘米水分的观测而得到显著提高。遥感水文学界一致认为1.4 GHz亮度是为此目的最有效的观测值。最近在辐射计技术、LSP/放射线亮度模型以及吸收放射线亮度的有效方案方面的突破，使我们走上了可靠的长期监测整个北极冻原内储存的水分的数量、状态和空间分布变化的道路。这一愿景的基本要素是来自卫星辐射计和校准的北极地形LSP/R模型的数据。欧洲航天局和美国国家航空航天局都在开发用于近地轨道的1.4 GHz合成孔径辐射计。水文学家正在为这些仪器的数据的出现做准备，他们开展了广泛的实地活动，以开发和校准LSP/R模型，并验证吸收卫星数据的方案。这些努力的重点是草原地形。尽管人们可以合理地认为遥感技术对北极的地球系统科学更为重要，但北极地形没有经过验证的LSP/R模型。成熟的北极地形LSP/R模型需要北极土壤和雪水文学家以及遥感水文学家的协作活动，这些活动由机载1.4 GHz成像辐射计提供的近每日区域数据支持。在接下来的十年里，只有三个这样的仪器被计划使用，其中20个在欧洲，另外一个是NASA的电子扫描薄阵列辐射计（ESTAR）的增强版，它搭载在NASA的P-3（一种大型4引擎涡轮螺旋桨飞机）上。P-3的高运营成本，P-3上仪器的冲突时间表，以及美国宇航局许多大型野外活动对ESTAR数据的需求，将极大地限制其在北极季节性和年际调查中的使用。PI的研究小组已经开发出第一个紧凑的1.4 GHz直接采样数字辐射计（DSDR）的例子。拟议的STAR-Light仪器将使用7个1.4 GHz DSDR接收器配置为二维合成孔径辐射计。STAR-Light将足够紧凑和坚固，可以在北极轻型飞机或无人驾驶飞行器（UAV）上运行。设计目标是使其符合Super Cub的性能和配置限制。STAR-Light将由密歇根大学的空间物理研究实验室（SPRL）设计、制造和测试3年。

AbstractOPP-0085176A.W. EnglandSTAR-Light - A 1.4 GHz Scanning Thinned Array Radiometer for use on light aircraft in arctic land-surface hydrologySTAR-Light will enable hydrologists to extend plot models of land-atmosphere energy and moisture transport processes to the circumpolar Arctic. Arctic energy balance experiments at sites that are both representative and accessible are used to develop Land-Surface Process (LSP) models, but extrapolating from these sites to the varying and mixed terrains of the circumpolar Arctic will require model calibration and validation that can be achieved only with frequent observations over broad regions beginning with spring thawing and ending with fall freezing. Once calibrated, these regional models will then serve either as improved lower boundaries of atmospheric models or as more reliable elements of integrated regional hydrology models. At the heart of the LSP model are estimates of moisture stored in soil, vegetation, and snow. The quality of these estimates and the skill of model predictions can be significantly improved by assimilating near-daily observations of the moisture in the upper few centimeters of soil. The remote sensing hydrology community has converged upon 1.4 GHz brightness as the most effective observation for this purpose. Recent breakthroughs in radiometer technology, in LSP/Radiobrightness models, and in efficient schemes for assimilating radiobrightness have placed us on a path toward reliable long-term monitoring of changes in the amount, state, and spatial distribution of moisture stored within tundra throughout the Arctic. Essential elements of this vision are data from satellite radiometers and calibrated LSP/R models for arctic terrains. Both the European Space Agency and NASA are developing 1.4 GHz synthetic aperture radiometers for low Earth orbit. Hydrologists are preparing for the advent of data from these instruments with extensive field campaigns to develop and calibrate LSP/R models, and to validate schemes for assimilating satellite data. The focus of these efforts has been prairie terrains. There are no proven LSP/R models for arctic terrains even though one could reasonably argue that remote sensing technologies are more vital to Earth system science in the Arctic. Mature LSP/R models for arctic terrains require collaborative campaigns involving arctic soil and snow hydrologists and remote sensing hydrologists supported by near-daily regional data from an airborne 1.4 GHz imaging radiometer. Only three such instruments are planned for the next decade -two in Europe and an enhanced version of NASA's Electronically Scanned Thinned Array Radiometer (ESTAR) which flies on the NASA P-3 -a large, 4-engine turboprop aircraft. The high operating costs of the P-3, the conflicting schedules of instruments on the P-3, and the demand for ESTAR data in NASA's many large field campaigns will greatly limit its use in seasonal and inter-annual investigations in the Arctic. The PI's research group has developed the first example of a compact, 1.4 GHz, Direct Sampling Digital Radiometer (DSDR). The proposed STAR-Light instrument will use seven 1.4 GHz DSDR receivers configured as a 2-dimensional synthetic aperture radiometer. STAR-Light will be sufficiently compact and robust to operate in the Arctic on a light aircraft or on an Uninhabited Aerial Vehicle (UAV). A design goal is that it fit within the performance and configuration limitations of a Super Cub. STAR-Light will be designed, fabricated, and tested over a 3-year period by the Space Physics Research Laboratory (SPRL) at the University of Michigan.