HR: 1400h
AN: H53C-05    [Abstracts]
TI: Mayan Historical drought trends
AU: * VELASCO HERERRA, V
EM: vmv@geofisica.unam.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, Mexico DF, DF 04510, Mexico
AU: MENDOZA, B E
EM: blanca@geofisica.unam.mx
AF: INSTITUTO DE GEOFISICA, UNIVERSIDAD NACIONAL AUTONOMA DE MEXICO, CIUDAD UNIVERSITARIA, COYOACAN, Mexico DF, DF 04510, Mexico
AU: GARCÍA-ACOSTA, V
EM: dirgral@ciesas.edu.mx.
AF: Centro de Investigaciones y Estudios Superiores en Antropología Social, Juárez 87, Mexico DF, DF 14000, Mexico
AB: In this work we present a more objective and general cycle-length determination of catalogues of past drought data for the Yucatan Peninsula between 1502 and 1900 coming from historical written documentation. We use the wavelet transformation based on the Morlet wavelet, and found that the most prominent frequencies of the historical drought series are ~ 3,4, 7, 12, 20, 43 and 70 years. We studied the relation between historical droughts and several large-scale climate phenomena represented by the Atlantic Multidecadal Oscillation (AMO) and the Southern Oscillation Index (SOI). Our results indicate that historical droughts and the cold phase of the AMO coincide, while the influence of the SOI is less clear. The strongest coincidences between historical droughts and AMO occurred around periodicities of 40 yrs. A further study of wavelet coherence shows that there are also common signal along time between droughts and various solar activity phenomena, in particular Be10, a proxy of cosmic rays. Comparing natural terrestrial and solar phenomena, we realize that the most sustained and strongest modulation of historical drought occurrence is at ~ 60-64 yrs and is between droughts and the solar proxy Be10.
DE: 1812 Drought
DE: 3255 Spectral analysis (3205, 3280)
DE: 3280 Wavelet transform (3255, 4455)
DE: 7536 Solar activity cycle (2162)
SC: Hydrology [H]
MN: 2007 Joint Assembly