MODIS Collection 5 Active Fire Product User's Guide Version ... - FAO

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4.2 MOD14A1 and MYD14A1The MOD14A1 and MYD14A1 daily Level 3 fire products are tile-based, with each product filespanning one of the 460 MODIS tiles, of which 326 contain land pixels. The product is a 1-kmgridded composite of fire pixels detected in each grid cell over each daily (24-hour) compositingperiod. For convenience, eight days of data are packaged into a single file.4.2.1 Fire MaskThe fire mask is stored as an 8 (or less) × 1200 × 1200, 8-bit unsigned integer SDS named “Fire-Mask”. (For historical reasons this layer was named “most confident detected fire” prior to Collection5.) The SDS contains eight successive daily fire masks for a specific MODIS tile. Each of thesedaily masks is a maximum value composite of the Level 2 fire product pixel classes (Table 2) forthose swaths overlapping the MODIS tile during that day. Product files containing less than eightdays of data will occasionally be encountered during time periods of missing data and should behandled in ingest software.4.2.2 QAEach of the daily fire masks has a corresponding simple QA layer. Each layer is a 1200 × 12008-bit unsigned integer array. Only three unique QA values are possible, with the meanings shownin Table 5.Table 5: QA values in Level 3 tile MODIS active fire products.Value Meaning0 Daytime observation or missing data, depending on the value in the correspondinggrid cell of the “FireMask” SDS.1 Nighttime observation.2 Sun glint rejection flag. Class in corresponding grid cell of “FireMask” SDS willbe non-fire clear land (5).4.2.3 Maximum FRPThe maximum fire radiative power of all fire pixels falling within each grid cell is provided on adaily basis in the “MaxFRP” SDS. Here the FRP values have been scaled by a factor of 10 andstored as a 32-bit signed integer. Multiply these scaled values by 0.1 to retrieve the maximum FRPin MW.4.2.4 Scan SampleFor all grid cells assigned one of the fire pixel classes (values 7, 8, or 9), the position of the fire pixelwithin the scan is recorded on a daily basis in a 1200 × 1200 16-bit unsigned integer SDS named“sample”. Sample values have a range of 0 to 1353. All grid cells assigned one of the non-fireclasses in the “FireMask” SDS will be filled with a sample value of 0.22
4.2.5 MetadataAs with the Level 2 fire products, the MOD14A1 and MYD14A1 products contain globalmetadata stored in the ECS CoreMetadata.0 and ArchiveMetadata.0 global attributes. Alsolike the Level 2 products, a subset of these metadata are written as standard HDF globalattributes for convenience (see Table 6). Here are example values for the product file“MOD14A1.A2009241.h31v10.005.2009250214231.hdf”, listed using ncdump (see Section7.8.4)::FirePix = 79, 148, 98, 102, 244, 129, 205, 197 ;:CloudPix = 72, 52, 316, 563, 81, 136, 171, 29 ;:UnknownPix = 78, 58, 61, 0, 34, 21, 151, 91 ;:MissPix = 163522, 0, 145360, 97779, 3373, 163624, 0, 163559 ;:MaxT21 = 382.34094f ;:ProcessVersionNumber = "5.1.3" ;:StartDate = "2009-08-29" ;:EndDate = "2009-09-05" ;:HorizontalTileNumber = 31s ;:VerticalTileNumber = 10s ;Notice that the first four fields (FirePix, CloudPix, UnknownPix, and MissPix) are onedimensionalarrays (or vectors) having eight elements. Each element corresponds to a single dayin the 8-day time period covered by the product. Note that while the Scientific Data Sets in theproduct file (“FireMask”, “MaxFRP”, etc.) will contain fewer than 8 planes when there are no validMODIS observations during one or more days spanned by the product, the vector metadata fieldswill always have eight elements. Those days completely lacking MODIS observations (as when theTerra MODIS was not operational for several weeks in June 2001) will have a value of 1200×1200= 1440000 in the appropriate element of the MissPix attribute.Table 6: MOD14A1 and MYD14A1 fire product metadata stored as standard global HDF attributes.Attribute Name DescriptionFirePixNumber of 1-km tile cells containing fires (8-element array).CloudPixNumber of 1-km tile cells assigned a class of cloud after compositing(8-element array).MissPixNumber of 1-km tile cells lacking valid data (8-element array).UnknownPixNumber of 1-km tile cells assigned a class of unknown after compositing(8-element array).MaxT21Maximum band 21 brightness temperature (K) of all fire pixels intile.ProcessVersionNumber Program version string (e.g. “5.1.3”).StartDateStart date of 8-day time period spanned by product (YYYY-MM-DD).EndDateEnd date of 8-day time period spanned by product (YYYY-MM-DD).HorizontalTileNumber Horizontal tile coordinate (H).VerticalTileNumber Vertical tile coordinate (V).23
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Page 3: 4.3.1 Fire Mask . . . . . . . . . .
Page 6: List of Tables1 MODIS fire product
Page 9 and 10: Figure 2: Example MOD14 granule wit
Page 11 and 12: 2.6 Climate Modeling Grid Fire Prod
Page 13 and 14: 2.9 LDOPE Global Browse ImageryThe
Page 15 and 16: 3.1 The Warehouse Inventory Search
Page 17 and 18: 3.2.3 DocumentationThe most recent
Page 19 and 20: 4.1.3 Algorithm Quality Assessment
Page 21: 4.1.6 Example CodeExample 1: IDL co
Page 25 and 26: Inverse MappingHere we are given th
Page 27 and 28: 4.3 MOD14A2 and MYD14A2The MOD14A2
Page 29 and 30: Example 6: C code for reading Level
Page 31 and 32: Satellite‘O’ = Terra‘Y’ = A
Page 33 and 34: 4.5 Global Monthly Fire Location Pr
Page 35 and 36: 5 Validation of the MODIS Active Fi
Page 37 and 38: 6.2.3 False Alarms in Small Forest
Page 39 and 40: 7 Frequently Asked Questions7.1 Ter
Page 41 and 42: 7.3.7 What validation of the MODIS
Page 43 and 44: assume these have been read and sto
Page 45 and 46: 7.5 Level 3 Tiled Fire Products7.5.
Page 47 and 48: 7.6 Level 3 CMG Fire Products7.6.1
Page 49 and 50: 7.6.2 Why don’t you distribute a
Page 51 and 52: Figure 14: DS9 displaying the CorrF
Page 53 and 54: 7.6.7 Does the last 8-day CMG produ
Page 55 and 56: 7.7 Global Monthly Fire Location Pr
Page 57 and 58: 7.9 Miscellaneous Questions7.9.1 Ar
Page 59 and 60: Morisette, J. T., Giglio, L., Csisz
Page 61: • SSEC Terra and Aqua Orbit Track

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