Bióloga

INT. J. REMOTE SENSING, VOL.

25,

NO.

20 OCTOBER, 2004, 20, 4417–4423

4. Multitemporal analysis of land surface temperature using NOAA-AVHRR: preliminary relationships between climatic anomalies and forest fires
´ L. MANZO-DELGADO*{, R. AGUIRRE-GOMEZ{ and ´ R. ALVAREZ§
{Facultad de Ciencias, {Instituto de Geografıa, §Instituto de Investigaciones ´ en Matematicas Aplicadas y enSistemas, Universidad Nacional Autonoma de ´ ´ Mexico, Mexico, DF 04510 ´ ´ (Received 8 August 2003; in final form 1 May 2004 ) Abstract. Advanced Very High Resolution Radiometer (AVHRR) National Oceanic and Atmospheric Administration (NOAA)-14 imagery was used to analyse changes in land surface temperature in an area of Central Mexico during the course of each dry season (November–April) for the period1996–2000. Daily surface temperature was obtained by the split-window method and cloud-free monthly composites were subsequently built. This value was related to maximum air temperatures recorded at meteorological stations and to forest fires detected from night-time images. During 1996–1997 and 1997–1998 (El Nino) dry ˜ seasons, monthly surface temperature ranged from 35‡C to 46‡C and from 33‡C to51‡C, respectively; during 1998–1999 (La Nina) and 1999–2000 it was lower, ˜ ranging from 28‡C to 47‡C, and from 28‡C to 41‡C, respectively. At the end of El Nino, land surface temperatures higher than 50‡C were registered, and 730 ˜ forest fires were detected, suggesting that this temperature increment also contributed to the vulnerability of vegetation to fire. It is concluded that land surfacetemperature during the first four months of the dry season can be used as a variable for modelling the probability of forest fire occurrence, in combination with other environmental variables. Similarities between land surface temperature and maximum air temperature suggest the potential use of NOAA-AVHRR imagery for evaluating El Nino/La Nina effects on the continental surface. ˜ ˜

1.Introduction The 1997–1998 El Nino Southern Oscillation (ENSO) phenomenon was ˜ considered the strongest of the last century (Wolter and Timlin 1998). It started in May 1997 and finished in June 1998. Its effects became apparent at a global scale (Coghlan 2002). Forest fires of great magnitude were facilitated by the intense droughts produced by ENSO (Rowell and Moore 2000). In July 1998, the Tropical Pacifictemperature decreased quickly, showing the first effects of the La Nina ˜ climatic phenomenon (McPhaden 1999), which is colder and wetter, and also modifies continental climatic conditions.
*Corresponding author; e-mail: llmanzo@igiris.igeograf.unam.mx
International Journal of Remote Sensing ISSN 0143-1161 print/ISSN 1366-5901 online # 2004 Taylor & Francis Ltd http://www.tandf.co.uk/journalsDOI: 10.1080/01431160412331269643

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ENSO effects induce many anomalies in climate (e.g. excessive precipitation and intense dryness) and in oceanic conditions (e.g. increase in the sea surface temperature), which have been studied thoroughly. In contrast, the ENSO effects on land surface temperature (LST) have seldom been analysed. The LST, which can be estimatedfrom remote sensing techniques, potentially represents a descriptive parameter for determining ENSO/La Nina effects inland. ˜ LST is a physical parameter influenced by solar radiation and heat exchange between land surface and atmosphere (Xue and Cracknell 1996). Thermal channels 4 (10.3–11.3 mm) and 5 (11.5–12.5 mm) of the Advanced Very High Resolution Radiometer (AVHRR), on board National Oceanicand Atmospheric Administration (NOAA) meteorological satellites, are used widely to obtain LST through the split-window algorithm, which involves brightness temperature and soil and vegetation emissivity (Price l984, Becker and Li 1990, Sobrino et al. 1991, Coll and Caselles 1997, Kant and Badarinath 2000). Ouaidrari et al. (2002) compared the LST with the maximum air temperature (MAT) from...