MODIS/Aqua Geolocation Fields 1km 5-Min 1A Wide Swath Subset along CloudSat V002 (MAC03S1) at GES DISC

This is the wide-swath MODIS/Aqua subset along CloudSat field of view track. The goal of the wide-swath subset is to select and return MODIS data that are within +-100 km across the CloudSat track. I.e. the resultant MODIS subset swath is about 200 km cross-track. Thus, MAC03S1 cross-track width is 201 pixels. Along-track, all MODIS pixels from the original product are preserved.

In the standard product, geolocation fields are calculated for each 1 km MODIS Instantaneous Field of Views (IFOV) for all orbits daily. The locations and ancillary information corresponds to the intersection of the centers of each IFOV from 10 detectors in an ideal 1 km band on the Earth's surface. A digital terrain model is used to model the Earth's surface. The main inputs are the spacecraft attitude and orbit, the instrument telemetry and the digital elevation model. The geolocation fields include geodetic Latitude, Longitude, surface height above geoid, solar zenith and azimuth angles, satellite zenith and azimuth angles, and a land/sea mask for each 1 km sample. Additional information is included in the header to enable the calculation of the approximate location of the center of the detectors of any of the 36 MODIS bands. This product is used as input by a large number of subsequent MODIS products, particularly the products produced by the Land team.

(The shortname for this product is MAC03S1).

本数据集为沿CloudSat卫星视场轨迹截取的宽刈幅中分辨率成像光谱仪（Moderate Resolution Imaging Spectroradiometer, MODIS/Aqua）子集。该宽刈幅子集的设计目标为选取并返回CloudSat卫星轨迹两侧±100公里范围内的MODIS数据。换言之，最终生成的MODIS子集刈幅的跨轨方向约为200公里，因此MAC03S1的跨轨宽度为201个像素。沿轨方向则保留原始产品的全部MODIS像素。

在标准产品中，每日所有轨道的1公里分辨率MODIS瞬时视场（Instantaneous Field of Views, IFOV）均会计算其地理定位字段。其位置与辅助信息对应于地球表面理想1km波段中10个探测器各自瞬时视场中心的交点。数据集采用数字地形模型对地球表面进行建模，核心输入参数包括航天器姿态与轨道、仪器遥测数据以及数字高程模型。地理定位字段包含每个1km采样点的大地纬度、大地经度、大地水准面以上的地表高程、太阳天顶角与方位角、卫星天顶角与方位角，以及海陆掩码。数据头文件中包含额外信息，可用于计算36个MODIS波段中任意一个波段的探测器中心近似位置。该产品可作为大量后续MODIS产品的输入数据，尤以陆面业务团队生成的产品为甚。

（该产品的短名称为MAC03S1。）