Assessing onset and length of greening period in six vegetation types in Oaxaca, Mexico, using NDVI-precipitation relationships
Por:
Gomez-Mendoza, L, Galicia, L, Cuevas-Fernandez, ML, Magana, V, Gomez, G, Palacio-Prieto, JL
Publicada:
1 jul 2008
Resumen:
Variations in the normalized vegetation index (NDVI) for the state of Oaxaca, in southern Mexico, were analyzed in terms of precipitation anomalies for the period 1997-2003. Using 10-day averages in NDVI data, obtained from AVHRR satellite information, the response of six types of vegetation to intra-annual and inter-annual fluctuations in precipitation were examined. The onset and temporal evolution of the greening period were studied in terms of precipitation variations through spectral analysis (coherence and phase). The results indicate that extremely dry periods, such as those observed in 1997 and 2001, resulted in low values of NDVI for much of Oaxaca, while good precipitation periods produced a rapid response (20-30 days of delay) from a stressed to a non-stressed condition in most vegetation types. One of these rapid changes occurred during the transition from dry to wet conditions during the summer of 1998. As in many parts of the tropics and subtropics, the NDVI reflects low
Filiaciones:
Gomez-Mendoza, L:
Univ Nacl Autonoma Mexico, Inst Geog, Coyoacan 04510, DF, Mexico
Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Coyoacan 04510, DF, Mexico
Galicia, L:
Univ Nacl Autonoma Mexico, Inst Geog, Coyoacan 04510, DF, Mexico
Cuevas-Fernandez, ML:
Univ Nacl Autonoma Mexico, Inst Geog, Coyoacan 04510, DF, Mexico
Magana, V:
Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Coyoacan 04510, DF, Mexico
Gomez, G:
Univ Nacl Autonoma Mexico, Inst Geog, Coyoacan 04510, DF, Mexico
Palacio-Prieto, JL:
Univ Nacl Autonoma Mexico, Inst Geog, Coyoacan 04510, DF, Mexico
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