fire Article Analysis of Trends in the FireCCI Global Long Term Burned Area Product (1982–2018) Gonzalo Otón 1, * , José Miguel C. Pereira 2 , João M. N. Silva 2 and Emilio Chuvieco 1   Citation: Otón, G.; Pereira, J.M.C.; Silva, J.M.N.; Chuvieco, E. Analysis of Trends in the FireCCI Global Long Term Burned Area Product (1982–2018). Fire 2021, 4, 74. https:// doi.org/10.3390/fire4040074 Academic Editor: Daniela Stroppiana Received: 17 August 2021 Accepted: 14 October 2021 Published: 17 October 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Grupo de Investigación en Teledetección Ambiental, Departamento de Geología, Geografíay Medio Ambiente, Universidad de Alcalá, Colegios 2, 28801 Alcalá de Henares, Spain; emilio.chuvieco@uah.es 2 Forest Research Centre, School of Agriculture, University of Lisbon, Tapada da Ajuda, 1349-017 Lisbon, Portugal; jmcpereira@isa.ulisboa.pt (J.M.C.P.); joaosilva@isa.ulisboa.pt (J.M.N.S.) * Correspondence: gonzalo.oton@uah.es Abstract: We present an analysis of the spatio-temporal trends derived from long-term burned area (BA) data series. Two global BA products were included in our analysis, the FireCCI51 (2001–2019) and the FireCCILT11 (1982–2018) datasets. The former was generated from Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m reflectance data, guided by 1 km active fires. The FireCCILT11 dataset was generated from Land Long-Term Data Record data (0.05 ◦ ), which provides a consistent time series for Advanced Very High Resolution Radiometer images, acquired from the NOAA satellite series. FireCCILT11 is the longest time series of a BA product currently available, making it possible to carry out temporal analysis of long-term trends. Both products were developed under the FireCCI project of the European Space Agency. The two datasets were pre-processed to correct for temporal autocorrelation. Unburnable areas were removed and the lack of the FireCCILT11 data in 1994 was examined to evaluate the impact of this gap on the BA trends. An analysis and comparison between the two BA products was performed using a contextual approach. Results of the contextual Mann-Kendall analysis identified significant trends in both datasets, with very different regional values. The long-term series presented larger clusters than the short-term ones. Africa displayed significant decreasing trends in the short-term, and increasing trends in the long-term data series, except in the east. In the long-term series, Eastern Africa, boreal regions, Central Asia and South Australia showed large BA decrease clusters, and Western and Central Africa, South America, USA and North Australia presented BA increase clusters. Keywords: burned area; AVHRR-LTDR; FireCCILT11; FireCCI51; spatiotemporal; contextual Mann-Kendall 1. Introduction Fire is a global phenomenon that affects ecosystems and the atmosphere [1–4]. It is a critical component of the Climate System and therefore it has been identified as one of the Essential Climate Variables (ECVs) by the Global Climate Observing System [1]. Consequently, Fire Disturbance was selected as one of the projects of the Climate Change Initiative (CCI) Programme of the European Space Agency (ESA). FireCCI aims to produce consistent, long-term and global Burned Area (BA) datasets, mostly oriented towards climate modellers [5]. This BA information is critical to assess the environmental impacts of biomass burning, as well as to analyse fire regime characteristics and temporal changes. During the last two decades, several global BA datasets have been produced and made available to the international community [6]. The most reliable ones are based on the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, including the MCD64A1 (NASA’s official product: [7]) and the FireCCI51 (ESA CCI’s official product: [8]). The spatial resolution of these datasets is 500 m and 250 m, respectively, and they cover a time span of 20 years (2001 up to date). Fire 2021, 4, 74. https://doi.org/10.3390/fire4040074 https://www.mdpi.com/journal/fire