Effects of Ellipsoidal Earth Model on Estimating the Sensitivity of Moon-Based Outgoing Longwave Radiation Measurements

Author(s):  
Hanlin Ye ◽  
Wei Zheng ◽  
Huadong Guo ◽  
Guang Liu
2021 ◽  
Vol 13 (11) ◽  
pp. 2201
Author(s):  
Hanlin Ye ◽  
Huadong Guo ◽  
Guang Liu ◽  
Jinsong Ping ◽  
Lu Zhang ◽  
...  

Moon-based Earth observations have attracted significant attention across many large-scale phenomena. As the only natural satellite of the Earth, and having a stable lunar surface as well as a particular orbit, Moon-based Earth observations allow the Earth to be viewed as a single point. Furthermore, in contrast with artificial satellites, the varied inclination of Moon-based observations can improve angular samplings of specific locations on Earth. However, the potential for estimating the global outgoing longwave radiation (OLR) from the Earth with such a platform has not yet been fully explored. To evaluate the possibility of calculating OLR using specific Earth observation geometry, we constructed a model to estimate Moon-based OLR measurements and investigated the potential of a Moon-based platform to acquire the necessary data to estimate global mean OLR. The primary method of our study is the discretization of the observational scope into various elements and the consequent integration of the OLR of all elements. Our results indicate that a Moon-based platform is suitable for global sampling related to the calculation of global mean OLR. By separating the geometric and anisotropic factors from the measurement calculations, we ensured that measured values include the effects of the Moon-based Earth observation geometry and the anisotropy of the scenes in the observational scope. Although our results indicate that higher measured values can be achieved if the platform is located near the center of the lunar disk, a maximum difference between locations of approximately 9 × 10−4 W m−2 indicates that the effect of location is too small to remarkably improve observation performance of the platform. In conclusion, our analysis demonstrates that a Moon-based platform has the potential to provide continuous, adequate, and long-term data for estimating global mean OLR.


Author(s):  
Chu Thi Thu Huong ◽  
Bui Thi Hop ◽  
Tran Dinh Linh ◽  
Vu Thanh Hang

Abstract: Based on the data that has the resolution is 1,00×1,00of the Outgoing Longwave Radiation (OLR) and the cloud cover from NCEP/NCAR in the 1981 – 2012 period, the relationship between the cloud cover and the OLR in the Southern of Vietnam wasinvestigated when analyze and compare the spatial distribution, temporal evolution and their correlation. The results show that the characteristics of the spatial distribution and the year cycle of cloud cover and OLR are inversely correlated. The region or time that the cloud cover is great, the OLR is small and vice versa. In the Southern of Vietnam, the OLR value isgreatest(or smallest) in the dry (or rainy) season and in the El-Nino (La-Nina) years. In addition, during the 1981-2012period, the OLR in this region shows a downward trend about 3.6 W/m2/decade, while the cloud cover tends to increase by 0.2%/decade. Keywords: Cloud cover, Outgoing Longwave Radiation, the Southern of Vietnam.


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