講演情報
[PPS02-P11]表面ラフネス・太陽高度補正を改良した月表面温度指示器 -ローバー経路計画のためのweb API-
*佐藤 理沙1、出村 裕英1 (1.会津大学)
キーワード：
ローバー、経路探索、月、API、表面温度、表面ラフネス
Lunar surface temperatures vary dramatically between day and night, making it essential to consider temperature planning paths for rover-based lunar explorations. While DIVINER observation data offers the highest precision and resolution, its massive data volume makes it unsuitable for immediate retrieval of temperatures at specific locations and times.
Therefore, this study has developed a web API that outputs temperature based on input geographical coordinates and UTC (Coordinated Universal Time). To reduce data volume, the API stores temperatures in a database, assuming the Moon is a true sphere. Since the lunar surface temperature is controlled by the geometry of the Sun and the local location, the API uses the temperature at a location with matching geometry. Latitude and local solar time are corrected based on the local slope, and temperatures at locations with the same geometry are referenced. This API calculates temperatures using a one-dimensional heat conduction model that assumes a flat surface. However, this model cannot sufficiently reproduce reabsorption due to surface roughness or shadow effects. These effects become particularly pronounced at low solar elevations, leading to discrepancies with observed values. Therefore, this study introduced correction functions dependent on solar elevation and surface roughness to improve temperature estimation accuracy under low solar elevation conditions. These correction functions were experimentally derived by analyzing the difference between calculated and observed values and are applied according to the solar elevation and roughness at each location.
This API enables the rapid acquisition of lunar surface temperatures without directly handling DIVINER's large data volumes. However, in low solar elevation, the error compared to actual measurements is significant, requiring further adjustments to the correction function.
Therefore, this study has developed a web API that outputs temperature based on input geographical coordinates and UTC (Coordinated Universal Time). To reduce data volume, the API stores temperatures in a database, assuming the Moon is a true sphere. Since the lunar surface temperature is controlled by the geometry of the Sun and the local location, the API uses the temperature at a location with matching geometry. Latitude and local solar time are corrected based on the local slope, and temperatures at locations with the same geometry are referenced. This API calculates temperatures using a one-dimensional heat conduction model that assumes a flat surface. However, this model cannot sufficiently reproduce reabsorption due to surface roughness or shadow effects. These effects become particularly pronounced at low solar elevations, leading to discrepancies with observed values. Therefore, this study introduced correction functions dependent on solar elevation and surface roughness to improve temperature estimation accuracy under low solar elevation conditions. These correction functions were experimentally derived by analyzing the difference between calculated and observed values and are applied according to the solar elevation and roughness at each location.
This API enables the rapid acquisition of lunar surface temperatures without directly handling DIVINER's large data volumes. However, in low solar elevation, the error compared to actual measurements is significant, requiring further adjustments to the correction function.