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

More documents

Recommendations

Info

4 Detailed Product Descriptions4.1 MOD14 and MYD14MOD14/MYD14 is the most basic fire product in which active fires and other thermal anomalies,such as volcanoes, are identified. The Level 2 product is defined in the MODIS orbit geometrycovering an area of approximately 2340 by 2030 km in the across- and along-track directions, respectively.It is used to generate all of the higher-level fire products.4.1.1 Fire MaskThe fire mask is the principle component of the Level 2 MODIS fire product, and is stored as an8-bit unsigned integer Scientific Data Set (SDS) named “fire mask”. In it, individual 1-km pixelsare assigned one of nine classes. The meaning of each class is listed in Table 2.Table 2: MOD14/MYD14 fire mask pixel classes.Class Meaning0 not processed (missing input data)2 not processed (other reason)3 water4 cloud5 non-fire clear land6 unknown7 low-confidence fire8 nominal-confidence fire9 high-confidence fireA pixel class of 1 was defined in the pre-launch algorithm but was abandoned as of Collection 3.4.1.2 Detection ConfidenceA detection confidence intended to help users gauge the quality of individual fire pixels is includedin the Level 2 fire product. This confidence estimate, which ranges between 0% and 100%, is used toassign one of the three fire classes (low-confidence fire, nominal-confidence fire, or high-confidencefire) to all fire pixels within the fire mask.In some applications errors of comission (or false alarms) are particularly undesirable, and forthese applications one might be willing to trade a lower detection rate to gain a lower false alarmrate. Conversely, for other applications missing any fire might be especially undesirable, and onemight then be willing to tolerate a higher false alarm rate to ensure that fewer true fires are missed.Users requiring fewer false alarms may wish to retain only nominal- and high-confidence fire pixels,and treat low-confidence fire pixels as clear, non-fire, land pixels. Users requiring maximum firedetectability who are able to tolerate a higher incidence of false alarms should consider all threeclasses of fire pixels.18
4.1.3 Algorithm Quality Assessment BitsPixel-level QA is stored in a 32-bit unsigned integer SDS named “algorithm QA”, with individualfields stored in specific bits. The exact meaning of these bit fields is defined in the Level 2 FireProduct file specification.4.1.4 Fire Pixel TableThe fire pixel table is simply a collection of SDSs containing relevant information about individualfire pixels detected within a granule. Due to HDF file format and library limitations, the Fire PixelTable is stored as 19 separate SDSs. A brief summary of these SDSs is provided in Table 3.Table 3: Collection 4 Level 2 fire product SDSs comprising the “fire pixel table”.SDS Name Data Type Units DescriptionFP line int16 - Granule line of fire pixel.FP sample int16 - Granule sample of fire pixel.FP latitude float32 degrees Latitude at center of fire pixel.FP longitude float32 degrees Longitude at center of fire pixel.FP R2 float32 - Near-IR (band 2) reflectance of fire pixel (daytime only).FP T21 float32 K Channel 21/22 brightness temperature of fire pixel.FP T31 float32 K Channel 31 brightness temperature of fire pixel.FP MeanT21 float32 K Background channel 21/22 brightness temperature.FP MeanT31 float32 K Background channel 31 brightness temperature.FP MeanDT float32 KFP MAD T21 float32 KFP MAD T31 float32 KFP MAD DT float32 KFP power float32 MW Fire radiative power.FP AdjCloud uint8 - Number of adjacent cloud pixels.FP AdjWater uint8 - Number of adjacent water pixels.FP WinSize uint8 - Background window size.FP NumValid int16 - Number of valid background pixels.FP confidence uint8 % Detection confidence estimate.4.1.5 MetadataEvery MODIS product carries with it ECS-mandated metadata stored in the HDF global attributesCoreMetadata.0 and ArchiveMetadata.0. Each attribute is an enormous string of ASCII charactersencoding many separate metadata fields in Parameter Value Language (PVL). Among other information,the ArchiveMetadata.0 attribute usually contains product-specific metadata included at thediscretion of the PI. However, since the PVL is awkward to read and tedious to parse, we have storedmany of the product-specific metadata fields as standard HDF global attributes. These are summarizedin Table 4. Descriptions of the product-specific metadata stored in the ECS ArchiveMetadata.0attribute may be found in the MOD14/MYD14 file specification (see Section 9).19
Page 1 and 2: MODIS Collection 5 Active Fire Prod
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: 3.2.3 DocumentationThe most recent
Page 21 and 22: 4.1.6 Example CodeExample 1: IDL co
Page 23 and 24: 4.2.5 MetadataAs with the Level 2 f
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

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

Create successful ePaper yourself

Delete template?

Save as template?