Lunar heat flow from the observation of Chinese Chang’E 2 and LRO diviner radiometers

Abstract

Lunar heat flow within 75°N to 65°S and 60°W to 100°E regions is retrieved from microwave brightness temperature observed by Chang’E-2 (CE-2) Lunar Microwave Radiometers and infrared brightness temperature observed by Lunar Reconnaissance Orbiter (LRO) Diviner Radiometers. The product of the regolith’s thermal conductivity and vertical temperature gradient yields the lunar heat flow. The vertical temperature gradient is calculated by a new temperature profile, the unknown parameters of which are determined from CE-2 microwave brightness temperature using a multi-layered lunar surface microwave brightness temperature model. The boundary condition of the temperature profile is determined by the LRO infrared brightness temperature. The measured heat flow at the Apollo 15 landing site is chosen as a calibration reference point in the retrieval process. The retrieved lunar heat flow within 75°N to 65°S and 60°W to 100°E regions ranged from 0.8 to 69.2 mW/m2. According to the retrieved results, lunar heat flow in the highlands is higher than the maria. The highest heat flux within 75°N to 65°S and 60°W to 100°E regions on the Moon are located toward the eastern highlands with an averaged heat flow value of 35.8 mW/m2, and the lowest heat flux is basically located in the typical maria such as Oceans Procellarum, Mare Imbrium, and Mare Serenitatis with an averaged heat flow value of 18.5 mW/m2.