Contents:

Algorithm Description
Scientific Data Sets
Local Attributes
Global Attributes
Quality Assurance

MOD11A1 Daily LST

The daily level 3 LST product at 1km spatial resolution is a tile of daily LST product gridded in the Integerized Sinusoidal projection (in V3) or the Sinusoidal projection (in V4). A tile contains 1200 by 1200 grids in 1200 rows and 1200 columns. The exact grid size at 1km spatial resolution is 0.928km by 0.928km.

Algorithm Description

The daily MOD11A1 LST product is constructed with the results in the MOD11_L2 products of a day through mapping the SDSs of all pixels in MOD11_L2 products onto grids in the integerized sinusoidal or sinusoidal projection and averaging the values in each grid.

As latitude increases beyond 30 degrees, the LST value at some grids in the MOD11A1 product may be the average value of LSTs retrieved from multiple MODIS observations in clear-sky conditions in day or night. If LST values from single clear-sky MODIS observations are required for all grids, the MOD11_L2 LST product and MODIS geolation product (MOD03) should be used instead.

Scientific Data Sets (SDS)

The SDSs in the MOD11A1 product include LST_Day_1km, QC_Day, Day_view_time, Day_view_angl, LST_Night_1km, QC_Night, Night_view_time, Night_view_angl, Emis_31, Emis_32, Clear_day_cov, Clear_night_cov, and Columns_per_Global_Grid_Row described in Table 9 Note that the scale factor and offset for Day_view_angle and Night_view_angle in V4 Level-3 MODIS LST products have been changed so that a negative sign of the viewing angle means MODIS viewing the grid from east. The view zenith angle itself is always a positive number, the zenith angle from nadir.  The information of MODIS viewing the grid from east or west may be important in understanding the view angle effect in the temporal variations in LSTs, especially in rugged regions. 

Table 9. The SDSs in the MOD11A1 product.
 
SDS
Name
Long
Name
Number
Type
Unit Valid
Range
Fill
Value
scale
factor
add
offset
LST_Day_1km Daily daytime 1km grid
Land-surface Temperature
uint16 K 7500-65535 0 0.02 0.0
QC_Day Quality control for daytime
LST and emissivity
uint8 none 0-255 0 NA NA
Day_view_time (local solar) Time of daytime Land-surface
Temperature observation
uint8 hrs 0-240 0 0.1 0
Day_view_angle View zenith angle of daytime
Land-surface Temperature
uint8 deg V3: 0-180

V4: 0-130
0

255
0.5

1.0
0

-65.0
LST_Night_1km Daily nighttime 1km grid
Land-surface Temperature
uint16 K 7500-65535 0 0.02 0.0
QC_Night Quality control for nighttime
LST and emissivity
uint8 none 0-255 0 NA NA
Night_view_time (local solar) Time of nighttime Land-surface
Temperature observation
uint8 hrs 0-240 0 0.1 0
Night_view_angle View zenith angle of nighttime
Land-surface Temperature
uint8 deg V3: 0-180

V4: 0-130
0

255
0.5

1.0
0

-65.0
Emis_31 Band 31 emissivity uint8 none 1-255 0 0.002 0.49
Emis_32 Band 32 emissivity uint8 none 1-255 0 0.002 0.49
Clear_day_cov day clear-sky coverage uint16 none 0-65535 0 *0.0001 0.
Clear_night_cov night clear-sky coverage uint16 none 0-65535 0 *0.0001 0.
** Columns_per_
Global_Grid_Row
Columns per row in the MODLAND
integerized sinusoidal grid
int32 none 0-43200 0 1 0

* The scale_factor 0.0001 was changed to 0.0004 since v2.3.6 and to 0.0005 since v2.5.1.

** SDS Columns_per_Global_Grid_Row is no longer included in the collection 3 MOD11A1.

Local Attributes

The local attributes for SDSs LST_Day_1km and LST_Night_1km are similar to those in Table 4. 

Global Attributes

Three ECS global attributes and 12 product-specific global attributes are stored as metadata. The ECS global attributes, CoreMetadata.0, ArchiveMetadata.0 and StructMetadata.0 are stored as very long character strings in PVL format. 

CoreMetadata.0 contains information about the product during production and is used to populate the EOSDIS data base for user support. A listing of objects along with sample values is given in Table 10.

Table 10. CoreMetadata.0 of the MOD11A1 data product.
 
Object Name Sample Value Comment
ShortName "MOD11A1" ESDT name of product
VersionID 1 ESC Version 
ReprocessingActual "processed once" Number of times processed.
ReprocessingPlanned "further update is anticipated" Expect that products will be reprocessed one or more times
LocalGranuleID "MOD11A1.A2000207.h09v05.002.2000246..hdf" Name of the granule.
DayNightFlag "Both"  
ProductionDateTime "2000-08-30T05:32:43.000Z" Time granule was produced.
LocalVersionID "SCF V2.2.16" Version of algorithm delivered from the SCF
PGEVersion "2.2.16" Version of PGE in MODAPS.
InputPointer "MOD03.A2000207.1915...hdf", "MOD021KM.A2000207...hdf",
...
Location of input files in the production system
RangeBeginningDate "2000-07-25" Beginning and ending times of the first and last scan line in the swath
RangeBeginningTime "19:16:40.322353"
RangeEndingDate "2000-07-05"
RangeEndingTime "19:18:11.904997"
ExclusionGRingFlag "N" latitude and longitude values of the corner grids in the tile
GringPointLatitude [39.995833, 39.995833, 30.004167, 30.004167]
GringPointLongitude [-117.474532, -104.421223, -92.374445, -103.921832]
GringPointSequenceNo [1, 2, 3, 4]
ParameterName "MOD 1KM L3 LST" Parameter for which QA statistics are given in this metadata object.
AutomaticQualityFlag "Passed" Result of automated checks done on the data during a run of algorithm. Useful for screening for anomalous data.
AutomaticQualityFlagExplanation "Passed if algorithm ran within bounds of execution constraints.  Suspect if bounds of execution constraints violated. Failed if PGE failed." Explanation of result of automated QA checks made during execution.
ScienceQualityFlag "Suspect" Set by LST investigator after post-production investigation
SciencelQualityFlagExplanation "Early product assessment is on going. Users are advised to use caution applying  these data to project-applications, especially in semi-arid and arid areas.  Input product are still being refined." Explanation of Science Flag
QAPercentMissingData 0 0 - 100
QAPercentCloudCover 95 0 - 100
AssociatedPlatformShortName "AM-1"  
AssociatedInstrumentShortName "MODIS"  
AssociatedSensorShortName "CCD"  
**Product Specific Attributes (PSA)**
QAPercentGoodQuality 5 Summary quality assurance statistic for data product. (0 - 100)
QAPercentOtherQuality 0
QAPercentNotProducedCloud 95
QAPercentNotproducedOther 0
N_GRAN_POINTERS "5" the number of granules
considered for the tile
HorizontalTileNumber "09"  
VerticalTileNumber "05"  
TileID "11009005"  
QAFractionGoodQuality 0.0536014 Summary fraction of the LST product. Range is from 0.0 to 1.0.
QAFractionOtherQuality 0.0000000
QAFractionNotProducedCloud 0.9463986
QAFractionNotProducedOther 0.0000000

The ECS global attribute ArchiveMetadata.0 contains information relevant to the input data, an alternate geographic coverage bounds, and information relevant to version of the algorithm and product. A listing of objects along with sample values is given in Table 11.

Table 11. ArchiveMetadata.0 of the MOD11A1 data product.
 
Object Name Sample Value Comment
HorizontalTileNumber "09"  
VerticalTileNumber "05"  
AlgorithmPackageAcceptanceDate "1997-11-01" Algorithm Descriptors
AlgorithmPackageMaturityCode "pre-launch"
AlgorithmPackageName "MOD_PR11_V2"
AlgorithmPackageVersion "Version 2"
InstrumentName "Moderate-Resolution Imaging SpectroRadiometer"  
ProcessingDateTime "2000-08-30T05:32:43.000Z"  
LongName "MODIS Level-3 1km Land Surface Temperature and Emissivity"  
ProcessingCenter "GSFC"  
SPSOParameters "2484 and 3323"  
LocalInputGranuleID "1915" only keep the time ID
EastBoundingCoordinate -92.374445 Extent of the tile coverage.
WestBoundingCoordinate -117.474532
NorthBoundingCoordinate 39.995833
SouthBoundingCoordinate 30.004167

The StructMetadata.0 global attribute is used by the HDF-EOS toolkit to create the mapping relationships between the defined grid and data (SDSs). 

Table 12. Listing of objects in the global attribute StructMetadata.0 in MOD11A1.
 
Object Definition
DIMENSION_1 XDim = 1200
DIMENSION_2 YDim = 1200
DataField_1 DataFieldName=LST_Day_1km
DataField_2 DataFieldName=QC_Day
DataField_3 DataFieldName=Day_view_time
DataField_4 DataFieldName=Day_view_angle
DataField_5 DataFieldName=LST_Night_1km
DataField_6 DataFieldName=QC_Night
DataField_7 DataFieldName=Night_view_time
DataField_8 DataFieldName=Night_view_angle
DataField_9 DataFieldName=Emis_31
DataField_10 DataFieldName=Emis_32
DataField_11 DataFieldName=Clear_day_cov
DataField_12 DataFieldName=Clear_night_cov
DataField_13 DataFieldName=Columns_per_Global_Grid_Row

Quality Assurance

The bit flags defined for the quality assurance SDSs QC_day and QC_Night are listed in Table 13

Table 13. Bit flags defined for SDSs QC_day and QC_Night in MOD11A1.  Note that bit 0 is the least significant bit. 
 
            A - in V3
 
bits Long Name Key
1 & 0 Mandatory QA flags 00=LST produced, good quality, not necessary to examine
  more detailed QA
01=LST produced, other quality, recommend examination of
  more detailed QA
10=LST not produced due to cloud effects
11=LST not produced primarily due to reasons other than cloud
  (such as ocean grid, grid not covered by all processed granules)
3 & 2 Data quality flag 00=good data quality
01=LST affected by thin cirrus and/or sub-pixel clouds
10=not processed due to missing pixels
11=not processed due to poor quality
5 & 4 Emis Error flag 00=average emissivity error <= 0.01
01=average emissivity error <= 0.02
10=average emissivity error <= 0.04
11=average emissivity error > 0.04
7 & 6 LST LST Error flag 00=average LST error <= 1K
01=average LST error <= 2K
10=average LST error <= 3K
11=average LST error > 3K

 
            B - in V4
 
bits Long Name Key
1 & 0 Mandatory QA flags 00=LST produced, good quality, not necessary to examine
  more detailed QA
01=LST produced, other quality, recommend examination of
  more detailed QA
10=LST not produced due to cloud effects
11=LST not produced primarily due to reasons other than cloud
3 & 2 Data quality flag 00=good data quality
01=other quality data
10=TBD
11=TBD
5 & 4 Emis Error flag 00=average emissivity error <= 0.01
01=average emissivity error <= 0.02
10=average emissivity error <= 0.04
11=average emissivity error > 0.04
7 & 6 LST LST Error flag 00=average LST error <= 1K
01=average LST error <= 2K
10=average LST error <= 3K
11=average LST error > 3K