AIRS/Aqua L3 daily CO2 in the free troposphere (AIRS+AMSU) 2.5 degrees x 2 degrees V005 (AIRX3C2D) at GES DISC

The Atmospheric Infrared Sounder (AIRS) is a grating spectrometer (R = 1200) aboard the second Earth Observing System (EOS) polar-orbiting platform, EOS Aqua. In combination with the Advanced Microwave Sounding Unit (AMSU) and the Humidity Sounder for Brazil (HSB), AIRS constitutes an innovative atmospheric sounding group of visible, infrared, and microwave sensors. This product is the AIRS mid-tropospheric Carbon Dioxide (CO2) Level 3 Daily Gridded Retrieval, from the AIRS and AMSU instruments on board of Aqua satellite. It is daily gridded data at 2.5x2 deg (lon)x(lat) grid cell size. The data is in mole fraction units (data x 10^6 =ppm in volume). This is a total tropospheric column property. The file format is HDF-EOS 2.12 corresponding to HDF4. This AIRS mid-tropospheric CO2 Level 3 daily Gridded Retrieval Product contains standard retrieval means, standard deviations and input counts as well as the latitude and longitude arrays giving the centers of the grid boxes. Each file covers a 24-hour period. The mean values are simply the arithmetic means of the individual CO2 retrievals which fall within that grid box over the period. The mid-tropospheric CO2 retrievals have been averaged and binned into 2.5 x 2 deg grid cells, from -180.0 to +180.0 deg longitude and from -60.0 to +90.0 deg latitude. For each grid map of 4-byte floating-point mean values there is a corresponding 4-byte floating-point map of standard deviation and a 2-byte integer grid map of counts. The counts map provides the user with the number of points per bin that were included in the mean.

大气红外探测仪（AIRS）是搭载于第二颗地球观测系统（EOS）极地轨道平台EOS Aqua上的光栅光谱仪（R = 1200）。结合先进的微波探测单元（AMSU）和巴西湿度探测仪（HSB），AIRS构成了一个创新的可见光、红外和微波传感器的组合大气探测组。本产品为AIRS中层大气二氧化碳（CO2）三级每日网格检索产品，数据源自搭载在Aqua卫星上的AIRS和AMSU仪器。该数据为每日网格数据，分辨率为2.5x2度（经度）x（纬度）的网格单元大小。数据以摩尔分数单位表示（数据 x 10^6 = 体积ppm）。这是一个总对流层柱状特性。文件格式为HDF-EOS 2.12，对应于HDF4。本AIRS中层大气CO2三级每日网格检索产品包含标准检索均值、标准偏差和输入计数，以及表示网格单元中心的纬度和经度数组。每个文件覆盖24小时周期。均值简单地为该网格单元内二氧化碳检索值的算术平均值。中层大气CO2检索值已平均并分箱至2.5x2度网格单元，经度范围为-180.0至+180.0度，纬度范围为-60.0至+90.0度。对于每个4字节浮点均值网格图，都有一个相应的4字节浮点标准偏差图和一个2字节整数计数网格图。计数图提供了每个箱中包含在均值计算中的点数。