HDF-EOS V2 MODIS daily L3 1km Surface Reflectance Aggregation Product
SCF Revision 5.1.1, July 2005, by K. Didan
Product ID(s): MODAGAGG L3 daily
Description:
MODIS Level 3 1km Land Surface Reflectance Aggregation (SRAGG) - The L3
SRAGG product contains surface reflectance at 1km resolution for bands
1 - 7. Multiple observations at any 250m or 500m grid cells read from
L2G input files are first aggregated (only good observations are used)
to produce a single reflectance value (for each band) for the grid by
computing weighted average of the observations. Observations are
weighted by the observation coverage. Observations from different
orbits are aggregated separately. All 250m or 500m observations that
fall into a 1km grid cell are then averaged to give the aggregated
reflectance value for that 1km grid.
Depending on the number of orbits present in the input L2G, for each
1km grid cell there will be one or more aggregated output. An aggregated
output observation for a 1km grid cell in the output tile contains four
angles (viewing and solar angles), seven reflectance values (bands 1-7),
seven band qa (bands 1-7) and a 1km state QA. For each pixel a maximum
of four aggregateed observations (from four different orbits) are
output. The observation that is closest to the nadir view is stored as
the first observation. Whenever more than one output observation is
present observations with diverse viewing geometry are selected for
output.
For pratical reasons, the Aggregation process will omitt all reflectances
below -100, emanating from the atmospheric correction process. Hence, all
surface reflectances will be within range -100 to 16000. Moreover, aggregation
takes place only on SHALLOW_OCEAN, LAND, OCEAN_COASTLINES, SHALLOW_INLAND_WATER,
EPHEMERAL_WATER pixels only.
The algorithm also implements a disk saving feature, where the number of output orbits
will depend on the latitude (Run time flag), with a maximum of 4 output orbits.
Point of Contact:
Kamel Didan
Terrestrial Biophysics & Remote Sensing.
1110 E. South Campus Drive, FCR Bldg#33, Room 313
University of Arizona,
Tucson, AZ 85721
(520) 621-8514
kamel@ag.arizona.edu
Principal Investigator(s):
Chris Justice
Univeristy of Maryland, College Park
NASA's Goddard Space Flight Center, Code 923
Greenbelt, MD 20771
(301) 286-7372
justice@kratmos.gsfc.nasa.gov
===========================================================================
Generic Constructs
ECS Metadata Strings:
Notes:
1. "FR" is an abbreviation for "FREE_RANGE".
2. "D/T" is an abbreviation for "DATE/TIME"
3. (A) means that multiple values are stored within a single array.
4. A value of "Variable" indicates that this value will vary
according to the granule being processed.
5. "M" means class M.
6. (C) means that multiple values are stored as class members.
CoreMetadata.0
This string will contain the following PVL fields:
#
Field Name Data of Value
Type Values
GROUP = INVENTORYMETADATA
GROUP = CollectionDescriptionClass
SHORTNAME STRING 1 "MODAGAGG"
VERSIONID INTEGER/ST 1 variable
END_GROUP = CollectionDescriptionClass
GROUP = ECSDataGranule
SIZEMBECSDATAGRANULE DOUBLE 1 Variable
REPROCESSINGPLANNED STRING 1 "no further update anticipated"
REPROCESSINGACTUAL STRING 1 "processed once"
LOCALGRANULEID STRING 1 Variable
DAYNIGHTFLAG STIRNG 1 Variable
PRODUCTIONDATETIME D/T 1 Variable
END_GROUP = ECSDataGranule
GROUP = PGEVersionClass
PGEVERSION STRING 1 "2"
END_GROUP = PGEVersionClass
GROUP = InputGranule
INPUTPOINTER STRING FR(A) Variable
END_GROUP = InputGranule
GROUP = RangeDateTime
RANGEBEGINNINGDATE DATE 1 Variable
RANGEBEGINNINGTIME TIME 1 Variable
RANGEENDINGDATE DATE 1 Variable
RANGEENDINGTIME TIME 1 Variable
END_GROUP = RangeDateTime
GROUP = SpatialDomainContainer
GROUP = HorizontalSpatialDomainContainer
GROUP = GPolygon
GROUP = GRing
EXCLUSIONGRINGFLAG STRING 1 "N"
END_GROUP = GRing
GROUP = GRingPoint
GRINGPOINTLATITUDE DOUBLE 4(A) Variable
GRINGPOINTLONGITUDE DOUBLE 4(A) Variable
GRINGPOINTSEQUENCENO INTEGER 4(A) Variable
END_GROUP = GRingPoint
END_GROUP = GPolygon
END_GROUP = HorizontalSpatialDomainContainer
END_GROUP = SpatialDomainContainer
GROUP = OrbitCalculatedSpatialDomain
ORBITNUMBER INTEGER FR(C) Variable
EQUATORCROSSINGLONGITUDE DOUBLE FR(C) Variable
EQUATORCROSSINGDATE DATE FR(C) Variable
EQUATORCROSSINGTIME TIME FR(C) Variable
END_GROUP = OrbitCalculatedSpatialDomain
GROUP = MeasuredParameter
PARAMETERNAME STRING 1 "Surface_Refl"
GROUP = QAFlags
AUTOMATICQUALITYFLAG STRING 1 Variable
AUTOMATICQUALITYFLAGEXPLANATION
STRING 1 Variable
OPERATIONALQUALITYFLAG STRING 1 variable
OPERATIONALQUALITYFLAGEXPLANATION
STRING 1 Variable
SCIENCEQUALITYFLAG STRING 1 variable
SCIENCEQUALITYFLAGEXPLANATION STRING 1 Variable
END_GROUP = QAFlags
GROUP = QAStats
QAPERCENTINTERPOLATEDDATA INTEGER 1 Variable
QAPERCENTMISSINGDATA INTEGER 1 Variable
QAPERCENTOUTOFBOUNDSDATA INTEGER 1 Variable
END_GROUP = QAStats
ENDGROUP = MeasuredParameter
GROUP = AdditionalAttributes
ADDITIONALATTRIBUTENAME STRING FR(C) Variable
PARAMETERVALUE STRING FR(C) Variable
ADDITIONALATTRIBUTENAME.1 = QAPERCENTGOODQUALITY
ADDITIONALATTRIBUTENAME.2 = QAPERCENTOTHERQUALITY
ADDITIONALATTRIBUTENAME.3 = QAPERCENTNOTPRODUCEDCLOUD
ADDITIONALATTRIBUTENAME.4 = QAPERCENTNOTPRODUCEDOTHER
ADDITIONALATTRIBUTENAME.5 = HORIZONTALTILENUMBER
ADDITIONALATTRIBUTENAME.6 = VERTICALTILENUMBER
ADDITIONALATTRIBUTENAME.7 = Tile_ID
ADDITIONALATTRIBUTENAME.7 = INPUTFILESRESOLUTION
END_GROUP = AdditionalAttributes
GROUP = AssociatedPlatformInstrumentSensor
ASSOCIATEDINSTRUMENTSHORTNAME STRING 1 "MODIS"
ASSOCIATEDPLATFORMSHORTNAME STRING 1 "Teraa"/"Aqua"
ASSOCIATEDSENSORSHORTNAME STRING 1 "MODIS"
END_GROUP = SensorCharacteristic
ENDGROUP = INVENTORYMETADATA
ProductMetadata.0
This string will contain the following PVL fields:
#
Field Name Data of Value
Type Valu
es
GROUP = ARCHIVEDMETADATA
GROUP = BoundingRectangle
NORTHBOUNDINGCOORDINATE DOUBLE 1 Variable
SOUTHBOUNDINGCOORDINATE DOUBLE 1 Variable
EASTBOUNDINGCOORDINATE DOUBLE 1 Variable
WESTBOUNDINGCOORDINATE DOUBLE 1 Variable
END_GROUP = BoundingRectangle
ALGORITHMPACKAGEACCEPTANCEDATE STRING 1 "2004-10-01"
ALGORITHMPACKAGEMATURITYCODE STRING 1 "Normal"
ALGORITHMPACKAGENAME STRING 1 "MODPRAGG"
ALGORITHMPACKAGEVERSION STRING 1 "5"
GEOANYABNORMAL STRING 1 Variable
GEOESTMAXRMSERROR DOUBLE 1 Variable
LONGNAME STRING 1 "MODIS 1km Aggregated Surface Reflectance"
PROCESSINGCENTER STRING 1 "MODAPS"
SYSTEMFILENAME STRING 1 Variable
NUMBEROFGRANULES INTEGER 1 Variable
GRANULEDAYNIGHTFLAG STRING FR(A) Variable
GRANULEBEGINNINGDATETIME D/T FR(A) Variable
GRANULEENDINGDATETIME D/T FR(A) Variable
NUMBEROFORBITS INTEGER 1 Variable
CHARACTERISTICBINANGULARSIZE DOUBLE 1 Variable
CHARACTERISTICBINSIZE DOUBLE 1 Variable
DATACOLUMNS INTEGER 1 Variable
DATAROWS INTEGER 1 Variable
GLOBALGRIDCOLUMNS INTEGER 1 Variable
GLOBALGRIDROWS INTEGER 1 Variable
NADIRDATARESOLUTION STRING 1 "1km"
REDUCEDVOLUME STRING 1 "YES or NO"
MAXIMUMNUMLAYERS INTEGER 1 Variable
MAXIMUMOBSERVATIONS INTEGER 1 Variable
COVERAGECALCULATIONMETHOD STRING 1 "area"
SPSOPARAMETERS STRING 1 "2015"
DESCRrevision STRING 1 Variable
ProductionHistory STRING 1 Variable
ENDGROUP = ARCHIVEDMETADATA
StructuralMetadata.0
This string will be populated automatically by HDF-EOS.
Grid Structure: MOD_Grid_Aggregation
Data Fields:
Angles, Surface_Refl, Band_QC, Aggregate_QC.
Dimensions:
Dimension Dimension Name Value
Dimension_0 YDim:MOD_Grid_Aggregation "DataRows"
Dimension_1 XDim:MOD_Grid_Aggregation "DataColumns"
Dimension_2 Num_Obs_Max "Num_Obs_Max"
Dimension_3 Num_Angles "Num_Angles"
Dimension_4 Num_Land_Bands "Num_Land_Bands"
Dimension_5 Num_Band_QC "Num_Band_QC"
Dimension_6 Num_Aggregate_QC "Num_Aggregated_QC"
Corner Locations:
Corner Values
UpperLeftPointMtrs (Variable, Variable)
LowerRightPointMtrs (Variable, Variable)
Geographic Grid Projection Parameters:
Integrized Sinusoidal Projection
Projection GCTP_ISINUS
ProjParam[0] 6371007.181
ProjParam[1 to 7] 0.0
ProjParam[8] 21600
ProjParam[9] 0.0
ProjParam[10] 1.0
ProjParam[11 to 12] 0.0
Spherecode -1
GridOrigin HDFE_GD_UL
Interrupted Goodes Homolosine Projection
Projection GCTP_GOOD
ProjParam[0 to 12] 0.0
Spherecode 19
GridOrigin HDFE_GD_UL
Lambert Azimuthal Equal Area Projection
Projection GCTP_LAMAZ
ProjParam[0] 6371228.0
ProjParam[1 to 5] 0.0
ProjParam[6] Variable
ProjParam[7 to 12] 0.0
Spherecode 19
GridOrigin HDFE_GD_UL
===========================================================================
Description of SDS Data Fields
-------------------------------
Data Field_1
------------
Data Field Name: Angles
Description: Viewing and illumination angles
Note:
Num_Angles #1 view zenith angle
Num_Angles #2 view azimuth angle
Num_Angles #3 solar zenith angle
Num_Angles #4 solar azimuthh angle
Type: HDF-int16
Dimensions:
Dimension Name Value
YDim DataRows
XDim DataColumns
Num_Obs_Max "Num_Obs_Max"
Num_Angles "Num_Angles"
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 19 "View and Sun Angles"
units STRING 8 degrees
valid_range INT16 2 -18000 18000
_FillValue INT16 1 -32767
Num_Obs_Max INT8 1 Variale (1,2,3, or 4)
Num_Angles INT8 1 4
scale_factor FLOAT64 1 0.01
add_offset FLOAT64 1 0.0
scale_factor_err FLOAT64 1 0.0
add_offset_err FLOAT64 1 0.0
calibrated_nt INT32 1 5
Data Field_2
------------
Data Field Name: Surface_Refl
Description: Surface Reflectance in bands 1-7
Type: HDF-int16
Dimensions:
Dimension Name Value
YDim DataRows
XDim DataColumns
Num_Obs_Max "Num_Obs_Max"
Num_Land_Bands "Num_Land_Bands"
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 19 "Surface Reflectance"
units STRING 11 reflectance
valid_range INT16 2 -100, 16000
_FillValue INT16 1 -1000
Num_Obs_Max INT8 1 Variale (1,2,3, or 4)
Num_Land_Bands INT8 1 7
scale_factor FLOAT64 1 0.0001
add_offset FLOAT64 1 0.0
scale_factor_err FLOAT64 1 0.0
add_offset_err FLOAT64 1 0.0
calibrated_nt INT32 1 5
Data Field_3
------------
Data Field Name: Band_QC
Description: QC in bands 1-7
Bits 0-1: Modland QA bits
key: 00: Product produced at ideal quality
01: Product produced, less than ideal quality.
10: Product not produced due to cloud effects.
- See Notes Below
11: Product not produced for other reason
Bits 2-5: Atmospheric Quality Flags
Dead Dectector flag superceeds other cases.
So a dead dectector flag does not exclude cases 9,10,11, and 12.
key: 0000: Highest Quality
0110: (6) dead detector; Less than 50% data has been copied from adjacent detector
0111: (7) dead detector; More that 50% data has been copied from adjacent detector
1000: (8) dead detector; (100%) All data has been copied from adjacent detector
1001: (9) solar zenith >= 85 degrees
1010: (10) solar zenith >= 75 and < 85 degrees
1011: (11) missing input
1100: (12) Internal constants used in place of climatology
1101: (13) Quality so low that it is not useful
1110: (14) L1B data faulty
1111: (15) not useful for any other reason/not processed
Bits 6-7: Geospatial Quality
key: 00: 25% or less of the finer resolution data contribued
to this 1km pixel
01: 50% "
10: 75% "
11: 100% "
Type: HDF-uint8
Dimensions:
Dimension Name Value
YDim DataRows
XDim DataColumns
Num_Obs_Max "Num_Obs_Max"
Num_Band_QC "Num_Band_QC"
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 7 "Band QC"
units STRING 13 class or flag
valid_range INT16 2 0, 254
_FillValue INT16 1 255
Num_Obs_Max INT8 1 Variale (1,2,3, or 4)
Num_Band_QC INT8 1 7
Data Field_4
------------
Data Field Name: Aggregate_QC
Description: Quality of the aggregate 1km Observations
Bits 0-1: Cloud State; clear (00), cloudy (01)
mixed (10), not set, assumed clear (11)
2 : Cloud shadow; yes (1) or no (0)
3-5: Land/water Flag;
000 Shallow ocean
001 Land (Nothing else but land)
010 Ocean coastlines and lake shorelines
011 Shallow inland water
100 Ephemeral water
101 Deep inland water
110 Moderate or continental ocean
111 Deep ocean
6-7: Aerosol quantity; climatology (00), low (01)
average (10), high (11)
8-9: Cirrus detected; none (00), small (01),
average (10), high (11)
10 : internal cloud mask; cloudy (1) or clear (0)
11 : internal fire mask; fire (1) or no fire (0)
12 : Snow/ice flag; yes (1) or no (0)
13 : Pixel is adjacent to cloud: (1) : YES or (0) : NO
14 : BRDF correction performed : (1) : YES or (0) : NO
15 : internal snow mask; snow (1) or no snow (0)
---- Note ---------------------------------------------------------------
Bits [10],[11] and [15] use to contain the following QA flags. Replaced
since Nov., 2001 production
10 : Water vapor data source; MOD05 (1) or climatology (0) (DAO or OORT)
11 : Ozone data source; MOD07 (1) or climatology (0) (DAO or London)
15 : Adjacent cloud detected; yes (1) or no (0)
Filed [13-14] was modified starting Collection 5.0. It is now broken into
two separate fields as (See above): It use to contain :
13-14: BRDF correction performed; no (00), Montana
methodology (01), Boston methodology (10)
-------------------------------------------------------------------------
Type: HDF-uint16
Dimensions:
Dimension Name Value
YDim DataRows
XDim DataColumns
Num_Obs_Max "Num_Obs_Max"
Num_Aggregate_QC "Num_Aggregate_QC"
HDF Attributes:
Number of
Values or
Max.
Attribute Data String Value
Type Length
long_name STRING 14 "Aggregate QC"
units STRING 5 class
valid_range INT16 2 0, 65534
_FillValue INT16 1 65535
Num_Obs_Max INT8 1 4
Num_Aggregate_QC INT8 1 1
NOTE: Janaury/2001 by Kamel Didan
------------------------------
A fix was implemented to properly compute the TEXTURE data. Right now
the code will compute the std-dec/mean for the band 1. It was not doing so before!
More filters are applied, to properly interpret MOD09 quality bits.
NOTE 1: June 12/2000 by Kamel Didan
------------------------------------
This is a MODLAND-wide decision stemming from the fact that
outputing "mediocre/cloudy" data is better than FILL data.
For at least the user will find (by inspecting the data) the
reasons why it was labeled as such. This will also allow the
generation of complete tiles, as opposed to tiles with holes of
missing data in them (Compare results from tiles prior and post
DOY 077/2000).
NOTE 2: July/1999 by Kamel Didan
------------------------------
The actual "Aggregate_QC" FILL VALUE is not 65535, it is a dynamic
FILL VALUE that is adjusted by the Land-Water mask. To be useful for any
comparison the user should mask the Land-Water field and then compare
to 65535 to realize wether it is FILL or not. This was done to convey
the correct Land-Water mask even when data was not present or bad.
NOTE 3: Deember/1999 by Kamel Didan
------------------------------
Minute adjustment to some Metadata VALIDS