MODIS MAIAC atmospheric properties (MCD19A2)
Description:
MAIAC is a new advanced algorithm which uses time series analysis and a combination of pixel- and image-based processing to improve accuracy of cloud detection, aerosol retrievals and atmospheric correction. Consistently with the entire C6 MODIS land processing, the top-of-atmosphere (TOA) L1B reflectance includes standard C6 calibration augmented with polarization correction for MODIS Terra, residual de-trending and MODIS Terra-to-Aqua cross-calibration (Lyapustin, A., Y. Wang, X. Xiong, G. Meister, S. Platnick, R. Levy, B. Franz, S. Korkin, T. Hilker, J. Tucker, F. Hall, P. Sellers, A. Wu, A. Angal (2014), Science Impact of MODIS C5 Calibration Degradation and C6+ Improvements, Atmos. Meas. Tech., 7, 4353-4365, doi:10.5194/amt-7-4353-2014).
The L1B data are first gridded into 1km MODIS sinusoid grid using area-weighted method. Due to cross-calibration, MAIAC processes MODIS Terra and Aqua jointly as a single sensor.
MAIAC provides a suite of atmospheric and surface products in three HDF-EOS 2.1.x files: daily MCD19A1 (spectral BRF, or surface reflectance), daily MCD19A2 (atmospheric properties), and 8-day MCD19A3 (spectral BRDF/albedo).
Point of Contact::
Yujie Wang
yujie.wang@nasa.gov
Principal Investigator(s):
Alexei Lyapustin
Code 613
NASA GSFC
8800 Greenbelt Road
Greenbelt, MD 20771
Phone: 301-614-5998
Email: alexei.i.lyapustin@nasa.gov
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General Construct
Geographic Grid Projection Parameters:
Sinusoidal Projection
Projection GCTP_SNSOID
ProjParam[0] 6371007.181
ProjParam[1 to 7] 0.0
ProjParam[8] 0.0
ProjParam[9] 0.0
ProjParam[10] 0.0
ProjParam[11 to 12] 0.0
Spherecode -1
GridOrigin HDFE_CENTER
dimensions:
Orbits:grid5km = variable (defined by global attribute Orbit_amount);
YDim:grid5km = 240 ;
XDim:grid5km = 240 ;
Orbits:grid1km = variable (defined by global attribute Orbit_amount);
YDim:grid1km = 1200 ;
XDim:grid1km = 1200 ;
variables:
short cosSZA(Orbits:grid5km, YDim:grid5km, XDim:grid5km) ;
cosSZA:long_name = "cosine of Solar Zenith Angle" ;
cosSZA:scale_factor = 0.0001 ;
cosSZA:add_offset = 0. ;
cosSZA:unit = "none" ;
cosSZA:_FillValue = -28672s ;
cosSZA:valid_range = 0s, 10000s ;
short cosVZA(Orbits:grid5km, YDim:grid5km, XDim:grid5km) ;
cosVZA:long_name = "cosine of View Zenith Angle" ;
cosVZA:scale_factor = 0.0001 ;
cosVZA:add_offset = 0. ;
cosVZA:unit = "none" ;
cosVZA:_FillValue = -28672s ;
cosVZA:valid_range = 0s, 10000s ;
short RelAZ(Orbits:grid5km, YDim:grid5km, XDim:grid5km) ;
RelAZ:long_name = "Relative Azimuth Angle" ;
RelAZ:scale_factor = 0.01 ;
RelAZ:add_offset = 0. ;
RelAZ:unit = "none" ;
RelAZ:_FillValue = -28672s ;
RelAZ:valid_range = -18000s, 18000s ;
short Scattering_Angle(Orbits:grid5km, YDim:grid5km, XDim:grid5km) ;
Scattering_Angle:long_name = "Scattering Angle" ;
Scattering_Angle:scale_factor = 0.01 ;
Scattering_Angle:add_offset = 0. ;
Scattering_Angle:unit = "none" ;
Scattering_Angle:_FillValue = -28672s ;
Scattering_Angle:valid_range = -18000s, 18000s ;
short Glint_Angle(Orbits:grid5km, YDim:grid5km, XDim:grid5km) ;
Glint_Angle:long_name = "Glint Angle" ;
Glint_Angle:scale_factor = 0.01 ;
Glint_Angle:add_offset = 0. ;
Glint_Angle:unit = "none" ;
Glint_Angle:_FillValue = -28672s ;
Glint_Angle:valid_range = -18000s, 18000s ;
short Optical_Depth_047(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
Optical_Depth_047:long_name = "AOT at 0.47 micron" ;
Optical_Depth_047:scale_factor = 0.001 ;
Optical_Depth_047:add_offset = 0. ;
Optical_Depth_047:unit = "none" ;
Optical_Depth_047:_FillValue = -28672s ;
Optical_Depth_047:valid_range = -100s, 4000s ;
short Optical_Depth_055(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
Optical_Depth_055:long_name = "AOT at 0.55 micron" ;
Optical_Depth_055:scale_factor = 0.001 ;
Optical_Depth_055:add_offset = 0. ;
Optical_Depth_055:unit = "none" ;
Optical_Depth_055:_FillValue = -28672s ;
Optical_Depth_055:valid_range = -100s, 4000s ;
short AOT_Uncertainty(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
AOT_Uncertainty:long_name = "AOT uncertainty at 0.47 micron, range 0-4" ;
AOT_Uncertainty:scale_factor = 0.0001 ;
AOT_Uncertainty:add_offset = 0. ;
AOT_Uncertainty:unit = "mm" ;
AOT_Uncertainty:_FillValue = -28672s ;
AOT_Uncertainty:valid_range = 0s, 30000s ;
short FineModeFraction(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
FineModeFraction:long_name = "Find mode fraction for Ocean" ;
FineModeFraction:scale_factor = 0.0001 ;
FineModeFraction:add_offset = 0. ;
FineModeFraction:unit = "none" ;
FineModeFraction:_FillValue = -28672s ;
FineModeFraction:valid_range = 0s, 10000s ;
short Column_WV(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
Column_WV:long_name = "Column Water Vapor (in cm liquid water)" ;
Column_WV:scale_factor = 0.001 ;
Column_WV:add_offset = 0. ;
Column_WV:unit = "cm" ;
Column_WV:_FillValue = -28672s ;
Column_WV:valid_range = 0s, 30000s ;
short AOT_QA(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
AOT_QA:long_name = "AOT_QA" ;
AOT_QA:unit = "none" ;
AOT_QA:data description = "Bits\tDefinition\n",
"0-2 Cloud Mask\n",
" 000 --- Undefined\n",
" 001 --- Clear\n",
" 010 --- Possible Cloudy\n",
" 011 --- Cloudy \n",
" 101 --- Cloud shadow\n",
" 110 --- Fire hotspot\n",
" 111 --- Water Sediments\n",
"3-4 Land Water Snow/ice Mask\n",
" 00 --- Land\n",
" 01 --- Water\n",
" 10 --- Snow\n",
" 11 --- Ice\n",
"5-7 Adjacency Mask\n",
" 000 --- Normal condition\n",
" 001 --- Adjacent to cloud\n",
" 010 --- Surrounded by more than 8 cloudy pixels\n",
" 011 --- Single cloudy pixel\n",
" 100 --- Adjacent to snow\n",
" 101 --- Snow was previously detected for this pixel\n",
"8-11 QA AOT \n",
" 0000 --- Best quality \n",
" 0001 --- Water Sediments are detected\n",
" 0010 --- AC over water done, but AOT>0.5\n",
" 0011 --- There is 1 neighbor cloud\n",
" 0100 --- There is >1 neighbor clouds\n",
" 0101 --- no retrieval (cloudy, or whatever)\n",
" 0110 --- no retrievals near detected or previously snow\n",
" 0111 --- Climatology AOT: altituide above 3.5km(water), and 4.2km(land)\n",
" 1000 --- no retrieval due to sun glint\n",
" 1001 --- retrieved AOT is very low (<0.05) due to glint\n",
" 1010 --- AOT within +-2km from the coastline is replaced by nearby AOT\n",
" 1011 --- Land, Reserach Quality: AOT retrieved but CM is possibly cloudy\n",
"12 Glint mask\n",
" 0 --- glint is not detected\n",
" 1 --- glint is detected\n",
"13-14 Aerosol model\n",
" 00 --- background model\n",
" 01 --- Smoke model\n",
" 10 --- Dust model\n",
"15 Reserved",
"" ;
AOT_QA:_FillValue = 0s ;
AOT_QA:valid_range = 0s, 255s ;
byte AOT_MODEL(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
AOT_MODEL:long_name = "AOT model used in retrieval" ;
AOT_MODEL:unit = "none" ;
AOT_MODEL:_FillValue = '\377' ;
AOT_MODEL:valid_range = '\0', '\12' ;
float Injection_Height(Orbits:grid1km, YDim:grid1km, XDim:grid1km) ;
Injection_Height:long_name = "Smoke Injection Height over local surface height, in km" ;
Injection_Height:unit = "meter" ;
Injection_Height:_FillValue = -99999.f ;
Injection_Height:valid_range = 0.f, 0.f ;