Moderate Resolution Imaging Spectroradiometer (MODIS) is satellite data. It is archived as digital data set DSI-3614 at the National Climatic Data Center (NCDC). Data is provided by the US National Aeronautics and Space Administration (NASA).Currently NCDC has, in archive, the data that is described below as MOD04_L2 and MOD05_L2 for year 2002 to the present. The rest of this abstract is an excerpt from a NASA MODIS web page: One of the most important ecological issues concerning our planet is climate change. It is generally agreed that the Earths climate will modify in response to radiative forcing induced by changes in atmospheric trace gases, cloud cover, cloud type, solar radiation, and tropospheric aerosols (liquid or solid particles suspended in the air). In order to develop conceptual and predictive global climate models, it is vital to monitor these properties. Two MODIS (Moderate Resolution Imaging Spectroradiometer) instruments, the first launched on 18 December 1999 onboard the Terra Platform and the second on 4 May 2002 onboard the Aqua platform, are uniquely designed (wide spectral range, high spatial resolution, and near daily global coverage) to observe and monitor these and other Earth changes. Level-2 MODIS Atmosphere Products There are six Level-2 (Orbital Swath) MODIS Atmosphere products collected from two platforms: the Terra platform and the Aqua platform. Each product is assigned an 8-character Earth Science Data Type (ESDT) name, given below, which is used in cataloging and archiving the datasets. The Level-2 MODIS Atmosphere products are: 1. The Aerosol Product monitors aerosol type, aerosol optical thickness, particle size distribution, aerosol mass concentration, optical properites, and radiative forcing. The ESDT names are MOD04_L2 (Terra) and MYD04_L2 (Aqua).2. The Water Vapor Product monitors atmospheric water vapor and precipitable water. The ESDT names are MOD05_L2 (Terra) and MYD05_L2 (Aqua). 3. The Cloud Product monitors the physical and radiative properties of clouds including cloud particle phase (ice vs. water, clouds vs. snow), effective cloud particle radius, cloud optical thickness, cloud shadow effects, cloud top temperature, cloud top height, effective emissivity, cloud phase (ice vs. water, opaque vs. non-opaque), and cloud fraction under both daytime and nighttime conditions. The ESDT names are MOD06_L2 (Terra) and MYD06_L2 (Aqua).4. The Atmosphere Profile Product monitors profiles of atmospheric temperature and moisture, atmospheric stability, and total ozone burden. The ESDT names are MOD07_L2 (Terra) and MYD07_L2 (Aqua).5. The Cloud Mask Product indicates whether a given instrument field of view (FOV) of the Earth's surface is unobstructed by clouds or affected by cloud shadows. The cloud mask also provides additional information about the FOV including the presence of: cirrus clouds, ice/snow, and sunglint contamination. Finally flags denoting day/night and land/water are included. The ESDT names are MOD35_L2 (Terra) and MYD35_L2 (Aqua).6. The post-launch Joint Atmosphere Product contains a spectrum of key parameters gleaned from the complete set of standard at-launch Level 2 products: Aerosol, Water Vapor, Cloud, Profile, and Cloud Mask. The Joint Atmosphere product was designed to be small enough to minimize data transfer and storage requirements, yet robust enough to be useful to a significant number of MODIS data users. Scientific data sets (SDS) contained within the Joint Atmosphere product cover a full set of high-interest parameters produced by the MODIS Atmosphere group, and are stored at 5-km and 10-km (at nadir) spatial resolutions. The ESDT names are MODATML2 (Terra) and MYDATML2 (Aqua).Level-3 MODIS Atmosphere Products There are three Level-3 (Global Gridded) MODIS Atmosphere products collected from two platforms. Each of the Level-3 products contain statistics generated from the first four Level-2 products noted above. Statistics are summarized over a 1x1 degree global grid for daily, eight-day, and monthly temporal periods. The Level-3 MODIS Atmosphere products are:1. The Daily Global Joint Product contains roughly 600 statistical datasets derived from Level-2 MODIS Atmosphere parameters that are summarized over a 24-hour (00 to 00 GMT) period. The ESDT names are MOD08_D3 (Terra) and MYD08_D3 (Aqua). 2. The Eight-Day Global Joint Product contains roughly 800 statistical datasets derived from Level-2 MODIS Atmosphere parameters that are summarized over an 8-day period. The ESDT names are MOD08_E3 (Terra) and MYD08_E3 (Aqua). 3. The Monthly Global Joint Product contains roughly 800 statistical datasets derived from Level-2 MODIS Atmosphere parameters that are summarized over a monthly period. It should be noted that the content of this product is identical to the Eight-Day Global Joint Product, except for the time period covered. The ESDT names are MOD08_M3 (Terra) and MYD08_M3 (Aqua).