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Item Comment on Otón et al. Analysis of Trends in the FireCCI Global Long Term Burned Area Product (1982–2018). Fire 2021, 4, 74(MDPI, 2022-04-11) Giglio, Louis; Zubkova, Maria; Roy, David P.In a recent study, Otón et al. [1] compared trends in global burned area (BA) mapped by the ESA Climate Change Initiative (CCI) MODIS-based FireCCI51 and AVHRR-based FireCCILT11 data sets. As noted by the authors, the two data sets were expected to be consistent, since the former was used to train the classification algorithm that generated the latter. To help establish this expected consistency, Otón et al. [1] examined the correlation between the respective gridded annual BA time series for the common 2001–2018 period, from which they concluded that “High spatial correlations are displayed with Pearson correlation (r) > 0.75 in pixels of all regions”. However, the authors overlooked several extensive zones in Africa where the BA time series were inconsistent and poorly correlated. The presence of these low-correlation zones notwithstanding, Otón et al. [1] reported widely predominant spatial agreement and only minor disagreement in BA trends for the 2001–2018 period. In this study, we explore inconsistencies between the FireCCI51 and FireCCILT11 BA in Africa, over zones that collectively encompass nearly one third of the entire continent. In addition, we note that the spatial extent over which FireCCI51 and FireCCILT11 BA trends do not agree was significantly larger when a more appropriate and less selective criterion for trend consistency was used.Item Detection, Evaluation, and Analysis of Global Fire Activity Using MODIS Data(2006-04-26) Giglio, Louis; Justice, Christopher O; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Global biomass burning plays a significant role in regional and global climate change, and spaceborne sensors offer the only practical way to monitor fire activity at these scales. This dissertation primarily concerns the development, evaluation, and use of the NASA Terra and Aqua MODIS instruments for fire monitoring. MODIS is the first satellite sensor designed specifically for global monitoring of fires. An improved operational fire detection algorithm was developed for the MODIS instrument. This algorithm offers a sensitivity to small, cool fires and minimizes false alarm rates. To support the accuracy assessment of the MODIS global fire product, an operational fire detection algorithm was developed and evaluated for the ASTER instrument, which provides higher resolution observations coincident with the Terra MODIS. The unique data set of multi-year MODIS day and night fire observations was used to analyze the global distribution of biomass burning using five different temporal metrics which included, for the first time, mean fire radiative power, a measure of fire intensity. The metrics show the planetary extent, seasonality, and interannual variability of fire. Recognizing differences in fire activity between morning and afternoon overpasses, the impact of the diurnal cycle of fire activity was addressed using seven years of fire data from the VIRS sensor on-board the TRMM satellite. A strong diurnal cycle was found in all regions, with the time of peak burning varying between approximately 13:00 and 18:30 local time. Given interest in area burned among atmospheric chemical transport and carbon cycle modelers, a data set was developed utilizing the MODIS global fire and vegetation cover products to estimate monthly burned area at 1-degree spatial resolution. The methods, products and results presented in this thesis provide the global change research and fire management communities with products for global fire monitoring and are currently being used in the development of the next generation of operational satellite fire monitoring systems.