MOD09Q1数据介绍.doc

Surface Reflectance 8-Day L3 Global 250mMOD09Q1Short Name: MOD09Q1 A combination of Bands 2, 2, 1 displays a false-color Surface Reflectance image using 250-m data acquired between February 1017, 2007 over parts of Chile and Argentina (h12v12). The fertile Central Valley of Chile appears to the southwest in red, as do the agricultural lowlands of Argentinas Las Pampas in the northeast corner of the image.The MODIS Surface Reflectance products provide an estimate of the surface spectral reflectance as it would be measured at ground level in the absence of atmospheric scattering or absorption. Low-level data are corrected for atmospheric gases and aerosols, yielding a level-2 basis for several higher-order gridded level-2 (L2G) and level-3 products.MOD09Q1 provides Bands 1 and 2 at 250-meter resolution in an 8-day gridded level-3 product in the Sinusoidal projection. Each MOD09Q1 pixel contains the best possible L2G observation during an 8-day period as selected on the basis of high observation coverage, low view angle, the absence of clouds or cloud shadow, and aerosol loading. Science Data Sets provided for this product include reflectance values for Bands 1 and 2, and a quality rating.Version-5 MODIS/Terra Surface Reflectance products are Validated Stage 2, meaning that accuracy has been assessed over a widely distributed set of locations and time periods via several ground-truth and validation efforts.Change Points of Interest Reduced file volume: internal compression Improved aerosol retrieval Version 005OverviewSee Product DescriptionLayersScience Data Sets for MODIS Terra Surface Reflectance 8-Day L3 Global 250m SIN Grid V005 (MOD09Q1):Science Data Sets (HDF Layers) (3)UNITSBIT TYPEFILLVALID RANGEMULTIPLY BY SCALE FACTOR250m Surface Reflectance Band 1 (620670 nm)Reflectance16-bit signed integer-28672-100160000.0001250m Surface Reflectance Band 2 (841876 nm)Reflectance16-bit signed integer-28672-100160000.0001250m Reflectance Band QualityBit Field16-bit unsigned integer65535032767naThe QA information below is excerpted from an HDF-EOS file of the MODIS Surface Reflectance product MOD09Q1. Table 1: MOD09Q1.005 250-meter Surface Reflectance Data QA Descriptions (16-bit)Bit No.Parameter NameBit Comb.Sur_refl_qc_250m15spare (unused)-14different orbit from 500 m1yes0no13adjacency correction performed1yes0no12atmospheric correction performed1yes0no811band 2 data quality four bit range0000highest quality1000dead detector; data copied from adjacent detector1001solar zenith = 86 degrees1010solar zenith = 85 and 86 degrees1011missing input1100internal constant used in place of climatological data for at least one atmospheric constant1101quality so low that it is not useful1110L1B data faulty1111not useful for any other reason or not processed due to deep ocean or clouds47band 1 data quality four bit rangeSAME AS ABOVE23cloud state00clear01cloudy10mixed11not set; assumed clear01MODLAND QA bits00corrected product produced at ideal quality all bands01corrected product produced at less than ideal quality some or all bands10corrected product not produced due to cloud effects all bands11corrected product not produced due to other reasons some or all bands may be fill value Note that a value of (11) overrides a value of (01).LinksUser Guide (PDF)Algorithm Theoretical Basis Document (PDF)Accuracy (MODIS Land Validation Website)Known Issues Basic Info Data Policies Data Access HelpData Set CharacteristicsTemporal Covera