Cloud Masks derived from Mars Daily Global Maps for MRO

This archive contains the cloud masks derived from the color Mars Daily Global Maps (MDGMs) composed from the Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI) wide-angle global map swaths. The procedure used is described in Wang and Gonzalez Abad [2021]. The MDGMs used include slight modifications from those at https://doi.org/10.7910/DVN/U3766S and are included in this archive. The product is at 0.1° longitude × 0.1° latitude resolution and is available for each day from Mars Year 28 Ls = 132° to Mars Year 29 Ls = 135° (i.e., MARCI subphases from P01 to P22 and B01). The data are organized according to subphases with each tar file corresponding to one subphase. Each subphase contains about a month of data and includes a list_ls.txt file, a cloudmask/ subdirectory and a mdgms/ subdirectory. The list_ls.txt file lists the name, Mars year and solar longitude (Ls) value for each MDGM. The MDGMs are in JPEG format. The cloud masks are in NetCDF format, and contains variables named “longitude”, “latitude”, and “cloudmask”. In the cloud masks, -999 Indicates invalid value due to missing or excluded data, 0 indicates non-cloudy pixel and positive values indicate cloudy pixels. The values for cloudy pixels are the adjusted Data Numbers of the blue channels of color MDGMs. For details, please refer to Wang, H. and Gonzalez Abad, G.: Cloud masks derived from Mars Daily Global Maps – An application to the tropical cloud belt on Mars. Submitted to Geosciences, July 2021.

本数据集档案包含基于火星勘测轨道飞行器（Mars Reconnaissance Orbiter, MRO）火星彩色成像仪（Mars Color Imager, MARCI）广角全球测绘条带合成的火星每日全球彩色地图（Mars Daily Global Maps, MDGMs）所生成的云掩膜产品。其生成流程详见Wang与Gonzalez Abad [2021]的研究成果。本档案所采用的MDGMs源自https://doi.org/10.7910/DVN/U3766S发布的原始数据并做了小幅调整，且本档案同时收录了这些经过调整的MDGMs数据。本产品的空间分辨率为0.1°经度 × 0.1°纬度，时间覆盖范围为火星年28的太阳经度（solar longitude, Ls）132°至火星年29的Ls=135°（对应MARCI的P01至P22以及B01子阶段）。本数据集按子阶段进行组织，每个tar压缩包对应一个子阶段。每个子阶段包含约一个月的观测数据，内含list_ls.txt文本文件、cloudmask/子目录以及mdgms/子目录。list_ls.txt文件会列出每个MDGM的文件名、所属火星年以及太阳经度（Ls）数值。MDGMs数据采用JPEG格式存储。云掩膜产品采用网络通用数据格式（NetCDF）存储，内含名为"longitude"、"latitude"与"cloudmask"的三个变量。在云掩膜数据中，数值-999代表因数据缺失或剔除而产生的无效值，0代表无云像素，正数值则代表有云像素。有云像素对应的数值为彩色MDGMs蓝通道经调整后的数字量化值（Data Numbers, DN）。如需了解更多细节，请参阅Wang, H.与Gonzalez Abad, G.于2021年7月提交给《Geosciences》期刊的研究论文：《基于火星每日全球地图生成的云掩膜——在火星热带云带研究中的应用》。