Manila Galleons Voyage Records: Readme file
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               World Data Center for Paleoclimatology, Boulder
                                  and
                     NOAA Paleoclimatology Program
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NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!!


NAME OF DATA SET: Manila Galleons Voyage Records
LAST UPDATE: 9/2005 (Addition of Manila to Acapulco voyage data in file acapulco-manila.doc)

CONTRIBUTOR: Rolando Garcia, National Center for Atmospheric Research

IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2002-005

SUGGESTED DATA CITATION: Garcia, R.R., et al., 2002,
Manila Galleons Voyage Records, 
IGBP PAGES/World Data Center for Paleoclimatology 
Data Contribution Series # 2002-005.
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.

ORIGINAL REFERENCE: Garcia, R.R., H.F. Díaz, R. García Herrera, 
J. Eischeid, M. del Rosario Prieto, E. Hernández, L. Gimeno, 
F. Rubio Durán, and A.M. Bascary, 2001, 
Atmospheric Circulation Changes in the Tropical Pacific 
Inferred from the Voyages of the Manila Galleons in the 
Sixteenth–Eighteenth Centuries, 
Bulletin of the American Meteorological Society, 
Volume 82, Number 11, pp. 2435, November 2001.

GEOGRAPHIC REGION: Tropical Pacific

PERIOD OF RECORD: 1591-1750 A.D.

LIST OF FILES: Readme_garcia2001.txt (this file),
acapulco-manila.doc (Microsoft Word format), 
duration.txt (tab-delimited text).

DESCRIPTION:
Garcia et al. 2001 Manila Galleons Voyage Records

acapulco-manila.doc:
Table of Acapulco-Manila Galleon voyages, start and arrival dates,
and relevant quotations from the Archivo General de Indias 
(in Spanish)

duration.txt: start dates and duration of voyages for each year.


Abstract:
Historical accounts of the voyages of the Manila galleons derived from the 
Archivo General de Indias (General Archive of the Indies, Seville, Spain)
are used to infer past changes in the atmospheric circulation of the 
tropical Pacific Ocean. It is shown that the length of the voyage between 
Acapulco, Mexico, and the Philippine Islands during the period 1590–1750 
exhibits large secular trends, such that voyages in the middle of the 
seventeenth century are some 40% longer than those at the beginning or at 
the end of the century, and that these trends are unlikely to have been 
caused by societal or technological factors.  Analysis of a series of 
"virtual voyages," constructed from modern wind data, indicates that 
sailing time to the Philippines depended critically on the strength 
of the trade winds and the position of the western Pacific monsoon trough. 
These results suggest that the atmospheric circulation of the western Pacific 
underwent large, multidecadal fluctuations during the seventeenth century.