<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0187-5779</journal-id>
<journal-title><![CDATA[Terra Latinoamericana]]></journal-title>
<abbrev-journal-title><![CDATA[Terra Latinoam]]></abbrev-journal-title>
<issn>0187-5779</issn>
<publisher>
<publisher-name><![CDATA[Sociedad Mexicana de la Ciencia del Suelo A.C.]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0187-57792019000400487</article-id>
<article-id pub-id-type="doi">10.28940/terra.v37i4.563</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Negative regional Standardized Precipitation Index trends prevail in the Mexico&#8217;s state of Zacatecas]]></article-title>
<article-title xml:lang="es"><![CDATA[Tendencias negativas del Índice de Precipitación Estandarizado regional predominan en el estado mexicano de Zacatecas]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Magallanes-Quintanar]]></surname>
<given-names><![CDATA[Rafael]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Blanco-Macías]]></surname>
<given-names><![CDATA[Fidel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Galván-Tejada]]></surname>
<given-names><![CDATA[Erick Carlos]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Galván-Tejada]]></surname>
<given-names><![CDATA[Jorge]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Márquez-Madrid]]></surname>
<given-names><![CDATA[Miguel]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Valdez-Cepeda]]></surname>
<given-names><![CDATA[Ricardo D.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
<xref ref-type="aff" rid="Aaf"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Autónoma de Zacatecas Unidad Académica de Ingeniería Eléctrica ]]></institution>
<addr-line><![CDATA[Zacatecas Zac]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Autónoma Chapingo Centro Regional Universitario Centro-Norte ]]></institution>
<addr-line><![CDATA[Zacatecas Zac]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Universidad Autónoma de Zacatecas Unidad Académica de Matemáticas ]]></institution>
<addr-line><![CDATA[Zacatecas Zac]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>12</month>
<year>2019</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>12</month>
<year>2019</year>
</pub-date>
<volume>37</volume>
<numero>4</numero>
<fpage>487</fpage>
<lpage>499</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0187-57792019000400487&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0187-57792019000400487&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0187-57792019000400487&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[SUMMARY: As the earth atmosphere warms, it is unclear how the precipitation will change or how these changes will impact regional rainfall. For the study of spatial and temporal variability of rainfall, several indexes have been developed. The Standardized Precipitation Index (SPI) that only involves recorded rainfall data has been used as a tool for climatic zone classification and a drought indicator. Then, the aims of the present study were: 1) to cluster monthly precipitation time series into groups that represent regions under the basis of similar precipitation regimes, 2) to compute regional SPI&#8217;s using all the members (time series) of each cluster, and 3) to estimate trends of the regional SPI&#8217;s. The cluster analysis approach was used to identify four groups of monthly precipitation time series that represent regions of similar precipitation regimes. Afterwards, regional SPI&#8217;s were estimated using all the members of each cluster. Finally, four regional SPI trends were estimated by means of the Mann-Kendall trend test and Sen&#8217;s slope estimator. Estimated decreasing SPI trends imply prevail of negative values at the end of the study period (1964-2014), which indicate less than median precipitation in the entire Zacatecas state territory. For instance, SPI at 12-month time scale Sen&#8217;s slope values were -0.17 and -0.18 for the wet and dry seasons, respectively in the Semi-desert region. Thus, the evidenced trends may be having influence on the availability of surface water, groundwater levels and aquifers recharge in the near future. So, it is imperative to adjust inhabitants&#8217; activities according to design planned climate change adaptation strategies.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[RESUMEN: Conforme la atmósfera terrestre se calienta no se aclara cómo la lluvia cambiará o cómo esos cambios impactarán sobre las lluvias a nivel regional. Para el estudio de la variabilidad espacial y temporal de la lluvia, varios índices se han desarrollado. El Índice de Precipitación Estandarizado (IPE), que solo involucra datos registrados de lluvia, se ha usado para clasificar zonas climáticas y como indicador de sequía. Entonces, los objetivos de este estudio fueron: 1) clasificar series de tiempo de precipitación mensual en grupos que representen regiones con base en regímenes similares de lluvia, 2) estimar IPE&#8217;s usando todos los miembros de cada clase, y 3) estimar las tendencia de los IPE&#8217;s regionales. La técnica de análisis de conglomerados se usó para identificar cuatro grupos de series de tiempo de lluvia mensual que representan regiones con regímenes similares de precipitación. Después, los IPE&#8217;s regionales se calcularon usando a todas las series integrantes de cada grupo. Finalmente, las tendencias de los IPE&#8217;s regionales se estimaron mediante la prueba de tendencia de Mann-Kendall y el estimador de pendiente de Sen. Las tendencias estimadas del IPE implican predominancia de valores negativos al final del período de estudio (1964-2014) que indican precipitación menor que la mediana en todo el territorio del estado de Zacatecas. Por ejemplo, en el caso del IPE a la escala de 12 meses, los valores de la pendiente de Sen fueron -0.17 y -0.18 para las estaciones húmeda y seca, respectivamente, en la región Semidesértica. Entonces, las tendencias evidenciadas pueden tener influencia sobre la disponibilidad de agua superficial, niveles de agua subterránea y recarga de acuíferos en el futuro cercano. Así, lo imperativo es ajustar las actividades de los habitantes de acuerdo a un diseño de estrategias planeadas de adaptación al cambio climático.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[climatic regions]]></kwd>
<kwd lng="en"><![CDATA[cluster analysis]]></kwd>
<kwd lng="en"><![CDATA[drought]]></kwd>
<kwd lng="en"><![CDATA[dry season]]></kwd>
<kwd lng="en"><![CDATA[wet season]]></kwd>
<kwd lng="es"><![CDATA[regiones climáticas]]></kwd>
<kwd lng="es"><![CDATA[análisis de conglomerados]]></kwd>
<kwd lng="es"><![CDATA[sequía]]></kwd>
<kwd lng="es"><![CDATA[estación seca]]></kwd>
<kwd lng="es"><![CDATA[estación húmeda]]></kwd>
</kwd-group>
</article-meta>
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