MW-Luna-2 – Establishing the Moon as reference for climate data from microwave sounders at low frequencies

MW-Luna-2 â 将月球作为低频微波探测仪气候数据的参考

• 批准号: 421761264
• 负责人: Professor Dr. Stefan Bühler
• 金额: --
• 依托单位: Meteorologisches Institut (MI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/421761264?language=en
• 关键词: MW; Luna; Establishing; Moon; reference

In a nutshell, the aim of the proposed project is to set the definitive value for the trend in tropospheric temperature and thus to put an end to the controversies surrounding the various microwave satellite observations. It is the intention to achieve this by establishing a flux reference with an unchangeable surface that has been observed by all microwave sounders many times over their operational lifetime: our Moon. In a precursor project it was demonstrated that the observed lunar brightness temperatures at a frequency of 89 GHz are in very good agreement with the predictions of a new model. The observations were obtained with AMSU-B (Advanced Microwave Sounding Unit - B) and MHS (Microwave Humidity Sounder). With AMSU-A and ATMS (Advanced Technology Microwave Sounder) it is possible to extend this investigation to lower frequencies, in particular the 54 GHz band. Published trends of the tropical tropospheric temperature based on this band range from 0.09° to 0.20° per decade, and these inconsistencies arose mainly from imperfect instrument calibration. In contrast stands the brightness temperature of the Moon, which depends only on its distance from the Sun and the viewing angle. This relationship can be characterized very accurately with the great number of observations that happened, when the Moon appeared serendipitously, i. e. during routine operations, in the deep space view of a microwave sounder. The focus of this study is on detecting changes, and the absolute value for the radiance of the Moon is obtained as a by-product. It would nevertheless be useful for future microwave sounders, in particular when the internal calibration source is dropped as a cost saving measure. Besides, the careful characterization of the disk-integrated brightness temperature of the Moon under various conditions of solar illumination would improve our understanding of the thermo-physical properties of its regolith. The observations to be analyzed were made with AMSU-A on nine different satellites and ATMS on two satellites. Together they cover all phase angles within some 80° around full Moon. Usually the Moon approaches the deep space view several times per year and shows then up in several orbits in a row. As most of the meteorological research satellites are more than ten years in service, one gets hundreds of observations of the Moon from each of them, betraying every possible instrumental anomaly and thus leading to its correction and the measurement of atmospheric temperatures with unprecedented accuracy.

简而言之，拟议项目的目的是确定对流层温度趋势的确定值，从而结束围绕各种微波卫星观测的争议。为了实现这一点，打算建立一个通量参考点，其表面是所有微波探测器在其使用寿命中多次观测到的一个不变的表面：我们的月球。在一个前体项目中，已经证明在89 GHz频率下观测到的月球亮度温度与新模型的预测非常一致。观测是用AMSU-B（高级微波探测装置- B）和MHS（微波湿度探测器）进行的。有了AMSU-A和ATMS（先进技术微波探测器），就有可能将这项研究扩展到更低的频率，特别是54 GHz频段。根据这一波段公布的热带对流层温度趋势范围为每十年0.09°至0.20°，这些不一致主要是由于仪器校准不完善造成的。相比之下，月球的亮度温度只取决于它与太阳的距离和视角。这种关系可以非常准确地用大量的观测来描述，当月球偶然出现时，即。e.在日常操作中，在微波探测器的深空视图中。这项研究的重点是检测变化，并获得了作为副产品的绝对值的月球的辐射。然而，这对未来的微波探测器是有用的，特别是当内部校准源作为节省成本的措施而被丢弃时。此外，在不同的太阳光照条件下，仔细描述月球的盘积分亮度温度将提高我们对其风化层的热物理特性的理解。将进行分析的观测是在9颗不同的卫星上用AMSU-A和在2颗卫星上用ATMS进行的。它们一起覆盖了满月周围约80°内的所有相位角。通常，月球每年都会多次接近深空视图，然后连续几次出现在轨道上。由于大多数气象研究卫星的服务年限都超过十年，因此每个卫星都能对月球进行数百次观测，从而泄露了每一种可能的仪器异常，从而导致其校正和以前所未有的精度测量大气温度。