NASA FIRMS - Active Fire

NASA’s Fire Information for Resource Management System (FIRMS) distributes Near Real-Time (NRT) Active Fire Data within 3 hours of satellite observation from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) and NASA’s Visible Infrared Imaging Radiometer Suite (VIIRS).

The European Forest Fire Information System (EFFIS) uses and redistributes the Active Fire Data provided by the NASA FIRMS.

Technical Background

The algorithms used by the MODIS and VIIRS instruments detect active fires on the basis of the thermal anomalies they produce. The contextual algorithms compare the temperature of a potential fire with the temperature of the land cover around it. If the difference in temperature is above a given threshold, the potential fire is confirmed as an active fire or “hot spot”.

A complete description of the MODIS and VIIRS algorithms can be found in the following articles:

• Giglio, Louis, et al. “An enhanced contextual fire detection algorithm for MODIS.
  Remote sensing of environment 87.2-3 (2003): 273-282.

• Schroeder, Wilfrid, et al. “The New VIIRS 375 m active fire detection data product: Algorithm description and initial assessment.” Remote Sensing of Environment 143 (2014): 85-96.

Downloading Datasets

NASA FIRMS:

• You can download MODIS and VIIRS Active Fire Data for the last 24, 48 hours and 7 days (.shp, .kml, .csv) from NASA Fire Information For Resource Management System here.

• Archive downloads for active fire/hotspot information older than the last 7 days are accessible here (country yearly summaries).

EFFIS: You can access the Modis and VIIRS Active Fire Data via the EFFIS data request for: https://effis.jrc.ec.europa.eu/static/data.request.form/

VIIRS dataset used in Pyro-Risks Training

from pyro_risks.datasets import NASAFIRMS, NASAFIRMS_VIIRS
viirs = NASAFIRMS_VIIRS()
modis = NASAFIRMS()

Datasets Descriptions

VIIRS MODIS Differences

The spatial resolution of the active fire detection pixel from MODIS is 1 km. The VIIRS active fire products provides an improved spatial resolution, as compared to MODIS. The spatial resolution of the active fire detection pixel for VIIRS is 375 m. Additionally, VIIRS is able to detect smaller fires and can help delineate perimeters of ongoing large fires. Additional information on the MODIS and VIIRS Active Fire products is available here (MCD14DL, VNP14IMGTDL_NRT).

Datasets	Availability	Update Frequency	Temporal Coverage	Revisit	Spatial Resolution	Spatial Coverage
MODIS C6 STANDARD	2-3 month	X	November 2000 - Present	~4-6 hours	1 km	Global
VIIRS 375 m (S-NPP) STANDARD	2-3 month	X	January 2012 - Present	~4-6 hours	375 m	Global
VIIRS 375 m (NOAA-20) STANDARD	2-3 month	X	January 2020 - Present	~4-6 hours	375 m	Global
MODIS C6 NRT	~3 hours	~6 hours	November 2000 - Present	~4-6 hours	1 km	Global
VIIRS 375 m (S-NPP) NRT	~3 hours	~6 hours	January 2012 - Present	~4-6 hours	375 m	Global
VIIRS 375 m (NOAA-20) NRT	~3 hours	~6 hours	January 2020 - Present	~4-6 hours	375 m	Global

VIIRS NRT Attribute Fields

Attribute	Short Description	Long Description
Latitude	Latitude	Center of nominal 375 m fire pixel
Longitude	Longitude	Center of nominal 375 m fire pixel
Bright_ti4	Brightness temperature I-4	VIIRS I-4 channel brightness temperature of the fire pixel measured in Kelvin.
Scan	Along Scan pixel size	The algorithm produces approximately 375 m pixels at nadir. Scan and track reflect actual pixel size.
Track	Along Track pixel size	The algorithm produces approximately 375 m pixels at nadir. Scan and track reflect actual pixel size.
Acq_Date	Acquisition Date	Date of VIIRS acquisition.
Acq_Time	Acquisition Time	Time of acquisition/overpass of the satellite (in UTC).
Satellite	Satellite	N= Suomi National Polar-orbiting Partnership (Suomi NPP)
Confidence	Confidence	This value is based on a collection of intermediate algorithm quantities used in the detection process. It is intended to help users gauge the quality of individual hotspot/fire pixels. Confidence values are set to low, nominal and high. Low confidence daytime fire pixels are typically associated with areas of sun glint and lower relative temperature anomaly (<15K) in the mid-infrared channel I4. Nominal confidence pixels are those free of potential sun glint contamination during the day and marked by strong (>15K) temperature anomaly in either day or nighttime data. High confidence fire pixels are associated with day or nighttime saturated pixels. Please note: Low confidence nighttime pixels occur only over the geographic area extending from 11° E to 110° W and 7° N to 55° S. This area describes the region of influence of the South Atlantic Magnetic Anomaly which can cause spurious brightness temperatures in the mid-infrared channel I4 leading to potential false positive alarms. These have been removed from the NRT data distributed by FIRMS.
Version	Version (Collection and source)	Version identifies the collection (e.g. VIIRS Collection 1) and source of data processing: Near Real-Time (NRT suffix added to collection) or Standard Processing (collection only). 1.0NRT - Collection 1 NRT processing. 1.0 - Collection 1 Standard processing.
Bright_ti5	Brightness temperature I-5	I-5 Channel brightness temperature of the fire pixel measured in Kelvin.
FRP	Fire Radiative Power	FRP depicts the pixel-integrated fire radiative power in MW (megawatts). Given the unique spatial and spectral resolution of the data, the VIIRS 375 m fire detection algorithm was customized and tuned in order to optimize its response over small fires while balancing the occurrence of false alarms. Frequent saturation of the mid-infrared I4 channel (3.55-3.93 µm) driving the detection of active fires requires additional tests and procedures to avoid pixel classification errors. As a result,sub-pixel fire characterization (e.g., fire radiative power [FRP] retrieval) is only viable across small and/or low-intensity fires. Systematic FRP retrievals are based on a hybrid approach combining 375 and 750 m data. In fact, starting in 2015 the algorithm incorporated additional VIIRS channel M13 (3.973-4.128 µm) 750 m data in both aggregated and unaggregated format.
Type*	Inferred hot spot type	0 = presumed vegetation fire 1 = active volcano 2 = other static land source 3 = offshore detection (includes all detections over water)
DayNight	Day or Night	D= Daytime fire, N= Nighttime fire

*This attribute is only available for VJ114IMGT (standard quality) data (coming soon)

Full description of the VIIRS dataset is available on the NASA Earth science data platform VNP14IMGTDL_NRT page.

MODIS NRT Attribute Fields

Attribute	Short Description	Long Description
Latitude	Latitude	Center of 1km fire pixel but not necessarily the actual location of the fire as one or more fires can be detected within the 1km pixel.
Longitude	Longitude	Center of 1km fire pixel but not necessarily the actual location of the fire as one or more fires can be detected within the 1km pixel.
Brightness	Brightness temperature 21 (Kelvin)	Channel 21/22 brightness temperature of the fire pixel measured in Kelvin.
Scan	Along Scan pixel size	The algorithm produces 1km fire pixels but MODIS pixels get bigger toward the edge of scan. Scan and track reflect actual pixel size.
Track	Along Track pixel size	The algorithm produces 1km fire pixels but MODIS pixels get bigger toward the edge of scan. Scan and track reflect actual pixel size.
Acq_Date	Acquisition Date	Data of MODIS acquisition.
Acq_Time	Acquisition Time	Time of acquisition/overpass of the satellite (in UTC).
Satellite	Satellite	A = Aqua and T = Terra.
Confidence	Confidence (0-100%)	This value is based on a collection of intermediate algorithm quantities used in the detection process. It is intended to help users gauge the quality of individual hotspot/fire pixels. Confidence estimates range between 0 and 100% and are assigned one of the three fire classes (low-confidence fire, nominal-confidence fire, or high-confidence fire).
Version	Version (Collection and source)	Version identifies the collection (e.g. MODIS Collection 6) and source of data processing: Near Real-Time (NRT suffix added to collection) or Standard Processing (collection only). ”6.0NRT” - Collection 6 NRT processing. ”6.0” - Collection 6 Standard processing. Find out more on collections and on the differences between FIRMS data sourced from LANCE FIRMS and University of Maryland.
Bright_T31	Brightness temperature 31 (Kelvin)	Channel 31 brightness temperature of the fire pixel measured in Kelvin.
FRP	Fire Radiative Power (MW - megawatts)	Depicts the pixel-integrated fire radiative power in MW (megawatts).
Type*	Inferred hot spot type	0 = presumed vegetation fire 1 = active volcano 2 = other static land source 3 = offshore
DayNight	Day or Night	D= Daytime fire, N= Nighttime fire

*This attribute is only available for MCD14ML (standard quality) data

Full description of the MODIS dataset is available on the NASA Earth science data platform MCD14DL page.

Acknowledgments

Data were provided by the European Forest Fire Information System – EFFIS (https://effis.jrc.ec.europa.eu) of the European Commission Joint Research Centre.

We acknowledge the use of data and imagery from LANCE FIRMS operated by NASA’s Earth Science Data and Information System (ESDIS) with funding provided by NASA Headquarters.