Show simple item record

dc.contributor.advisorMatthias, Allan D.en_US
dc.contributor.authorPeralta-Hernandez, Ana Rosa
dc.creatorPeralta-Hernandez, Ana Rosaen_US
dc.date.accessioned2013-08-15T10:12:57Z
dc.date.available2013-08-15T10:12:57Z
dc.date.issued2001en_US
dc.identifier.urihttp://hdl.handle.net/10150/298799
dc.description.abstractThe impacts of El Nino Southern Oscillation (ENSO) on precipitation, reference evapotranspiration, and vegetation in a three-state region of central Mexico were investigated using daily weather data from 20 weather stations for the years 1970 through 1990, which included 5 El Nino years, 5 La Nina years, and 11 Neutral years. In addition, two years, 1997 (El Nino), and 1998 (La Nina) of 10-day NDVI composites were analyzed during the growing season (May-Oct) along with precipitation and reference evapotranspiration (ETo) over central Mexico. Regional precipitation trends were analyzed using the normalized rainfall departures. The interannual variation of vegetation cover was analyzed using the NDVI on 10-day and monthly bases. The Food and Agricultural Organization (FAO) Penman-Monteith method was used to calculate ETo. The dynamics of the soil water balance in central Mexico was evaluated according to the method proposed by Thornthwaite and Mather. Analyses indicate that driest conditions occurred within the northern part of the region and during neutral ENSO years. Rainfall amounts during El Nino and Neutral years were not statistically different however, La Nina years were about 30% wetter than N and EN years (0.05 level). The correlation coefficient between NDVI and precipitation was 0.79 in 1997, and 0.52 in 1998, in June and July, respectively. Negative correlation was found between NDVI and reference evapotranspiration during the rainy months of July and August. The spatio-temporal variability of NDVI showed that there was significant statistical difference in NDVI between regions, but not between years. Regional soil water balance determinations indicated that conditions were most favorable in the Southern part of the region for crop growth during La Nina years. In general, soil water deficits were reduced by about 50% during the growing season compared to the annual soil water deficits.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectBiology, Ecology.en_US
dc.subjectAgriculture, Soil Science.en_US
dc.subjectPhysics, Atmospheric Science.en_US
dc.titleEl Nino Southern Oscillation (ENSO) effects on hydro-ecological parameters in central Mexicoen_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest3040144en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineSoil, Water and Environmental Scienceen_US
thesis.degree.namePh.D.en_US
dc.identifier.bibrecord.b42562557en_US
refterms.dateFOA2018-06-15T05:23:54Z
html.description.abstractThe impacts of El Nino Southern Oscillation (ENSO) on precipitation, reference evapotranspiration, and vegetation in a three-state region of central Mexico were investigated using daily weather data from 20 weather stations for the years 1970 through 1990, which included 5 El Nino years, 5 La Nina years, and 11 Neutral years. In addition, two years, 1997 (El Nino), and 1998 (La Nina) of 10-day NDVI composites were analyzed during the growing season (May-Oct) along with precipitation and reference evapotranspiration (ETo) over central Mexico. Regional precipitation trends were analyzed using the normalized rainfall departures. The interannual variation of vegetation cover was analyzed using the NDVI on 10-day and monthly bases. The Food and Agricultural Organization (FAO) Penman-Monteith method was used to calculate ETo. The dynamics of the soil water balance in central Mexico was evaluated according to the method proposed by Thornthwaite and Mather. Analyses indicate that driest conditions occurred within the northern part of the region and during neutral ENSO years. Rainfall amounts during El Nino and Neutral years were not statistically different however, La Nina years were about 30% wetter than N and EN years (0.05 level). The correlation coefficient between NDVI and precipitation was 0.79 in 1997, and 0.52 in 1998, in June and July, respectively. Negative correlation was found between NDVI and reference evapotranspiration during the rainy months of July and August. The spatio-temporal variability of NDVI showed that there was significant statistical difference in NDVI between regions, but not between years. Regional soil water balance determinations indicated that conditions were most favorable in the Southern part of the region for crop growth during La Nina years. In general, soil water deficits were reduced by about 50% during the growing season compared to the annual soil water deficits.


Files in this item

Thumbnail
Name:
azu_td_3040144_sip1_m.pdf
Size:
2.610Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record