Fernando S Rodrigo - Academia.edu (original) (raw)

Papers by Fernando S Rodrigo

Climate of The Past, Apr 4, 2019

Bulletin of the American Meteorological Society, 2020

The relationship between temperature and precipitation is not simple. Several physical processes ... more The relationship between temperature and precipitation is not simple. Several physical processes can determine whether this relationship is positive or negative, depending on the geographic location and the season. This paper proposes new indices for studying this relationship at a seasonal level, based on daily data of accumulated precipitation and mean temperature: the Rt(T75) index is defined as the percentage of precipitation corresponding to warm days in the year t, and Rt(T25) the one corresponding to cold days. The so-called "contribution index" is defined as the measurement and extent in which the Rt(T25) and Rt(T75) indices contribute to the each interval of percentage precipitation values. To synthesize the behavior of these indices the index IRt = Rt(T75)-Rt(T25) is proposed and compared to the ITt index, defined as the difference between the average temperature of wet days and that of dry days. These indices are analyzed for four meteorological stations that re...

Figures: Number of seasonal records and combined temperature-rainfall conditions for winter, spri... more Figures: Number of seasonal records and combined temperature-rainfall conditions for winter, spring, summer, and autumn, in five Spanish provinces (Seville, Córdoba, Jaén, Granada, and Murcia) Tables: Reports extracted from the data source CMEI

Cuadernos de Investigación Geográfica, 2018

espanolEl analisis de la variabilidad climatica en periodos historicos anteriores a la Revolucion... more espanolEl analisis de la variabilidad climatica en periodos historicos anteriores a la Revolucion Industrial permite estudiar los fenomenos climaticos antes de que las actividades humanas supusieran un factor clave de cambio climatico, y ofrece por tanto la posibilidad de profundizar en el conocimiento de la variabilidad climatica natural. En este trabajo se analizan las inundaciones de la ciudad de Sevilla en la decada de los 1780 a partir del analisis de diversas fuentes documentales. Esta decada se enmarca dentro de la fase final de la denominada Pequena Edad de Hielo (LIA). Se demuestra que las inundaciones fueron la consecuencia de un periodo de intensas precipitaciones (fundamentalmente en invierno y primavera), provocadas por el predominio de la fase negativa de la Oscilacion del Atlantico Norte (NAO). EnglishThe analysis of climate variability during historical periods previous to the Industrial Revolution allows study climatic phenomena before human activities were a climat...

Abstract. In this work, cluster and principal component analysis are used to divide Spain in a li... more Abstract. In this work, cluster and principal component analysis are used to divide Spain in a limited number of cli-matically homogeneous zones, based on seasonal rainfall for 32 Spanish localities for the period 1912–2000. Using the hierarchical technique of clustering Ward’s method, three clusters have been obtained in winter and spring, and four clusters have been obtained in summer and autumn. Results are similar to those obtained by applying principal compo-nent analysis. Centroid series of each cluster and principal component series of each EOF have been compared to ana-lyze the temporal patterns. The comparison of both methods indicates that cluster analysis is suitable to establish spatio-temporal patterns of seasonal rainfall distribution in Spain. Key words. Meteorology and atmospheric dynamics (cli-matology; precipitation; general or miscellaneous) 1

The main objectives of the manuscript are the following: *To improve the reconstructions of the c... more The main objectives of the manuscript are the following: *To improve the reconstructions of the climate in the study area (Andalusia, southern Iberian Peninsula), especially during the Dalton Minimum period, due to the role of natural climate forcings, such as the high volcanic activity and the low solar irradiance during this period. *To improve the reconstruction methodology, combining the methods of the historical climatology and the climate model simulations.

In this work, a reconstruction of winter rainfall and temperature in Andalusia (southern Iberia P... more In this work, a reconstruction of winter rainfall and temperature in Andalusia (southern Iberia Peninsula) during the period 1750-1850 is presented. The reconstruction is based on the analysis of a wide variety of documentary data. This period is interesting because it is characterized by a minimum in the solar irradiance (Dalton Minimum, around 1800), as well as intense volcanic activity (for instance, the eruption of the Tambora in 1815), when the increasing atmospheric CO2 concentrations were of minor importance. The reconstruction methodology is based on accounting the number of extreme events in past, and inferring mean value and standard deviation using the assumption of normal distribution for the climate variables. Results are compared with the behaviour of regional series for the reference period 1960-1990. The comparison of the distribution functions corresponding to 1790-1820 and 1960-1990 periods indicates that during the Dalton Minimum the frequency of droughts and warm winters was lesser than during the reference period, while the frequencies of wet and cold winters were similar. Future research work is outlined.

In relation to the ENSO, we investigated a possible relation between our data and Quinn El Niño I... more In relation to the ENSO, we investigated a possible relation between our data and Quinn El Niño Index, but results were negative (no correlation between them), and, in consequence, we excluded any comment on this item in the first versión of the manuscript. The influence of the ENSO phenomenon in the Sahel has been disputed, with some studies noting a tendency for the ENSO to be associated with reduced rainfall and others concluding that there is little consistent influence in the región (Nicholson SE,

Cuadernos de Investigación Geográfica, Feb 20, 2018

Andalusia (southern Spain) is a region of special climatic interest due to its geographical locat... more Andalusia (southern Spain) is a region of special climatic interest due to its geographical location, hydrological and orographical characteristics. In this work a summary of different approaches to study the Little Ice Age in this region is presented. From different proxy data (lake and marine sediments, geomorphological evidences, tree-rings, documentary data), it is possible to obtain the main characteristics of this climatic episode, with predominance of colder and wetter conditions than today and great variability. However, some uncertainties persist, related to the chronological limits of the LIA in the region, the variability of thermal and rainfall conditions, and different time resolution of various proxy data analysed. These problems are discussed and future research challenges are proposed. Una revisión sobre la Pequeña Edad del Hielo en Andalucía (sur de España): resultados y retos de investigación RESUMEN. Andalucía (sur de España) es una región de especial interés climático debido a su posición geográfica y sus características hidrológicas y orográficas. En este trabajo se presenta un resumen de las diferentes aproximaciones al estudio de la Pequeña Edad de Hielo en esta región. A partir de diferentes datos proxy (sedimentos lacustres y marinos, datos geomorfológicos, anillos de árboles, datos documentales) es posible inferir las principales características de este episodio climático, con predominio de condiciones más frías y húmedas que hoy y una gran variabilidad. Sin embargo, persisten algunas incertidumbres, relacionadas con los límites cronológicos de la Pequeña Edad de Hielo, la variabilidad de las condiciones térmicas y pluviométricas, y la diferente resolución temporal de los distintos datos proxy analizados. Se discuten estos problemas y se proponen futuras vías de investigación.

Clima, sociedad, riesgos y ordenación del territorio, 2016

En este trabajo se analiza la influencia de la Oscilación del Atlántico Norte (NAO) en la covaria... more En este trabajo se analiza la influencia de la Oscilación del Atlántico Norte (NAO) en la covariabilidad de temperaturas y precipitaciones de invierno de 18 estaciones meteorológicas distribuidas por el territorio peninsular español durante el periodo 1946-2005. La covariabilidad entre precipitaciones totales acumuladas (R) y media estacional de las temperaturas máximas diarias (TX), mínimas diarias (TN), medias diarias (TM), y del rango diurno de temperaturas (DTR), fue analizada comparando los resultados obtenidos para las distintas fases de la NAO. Entre las variables relacionadas con la temperatura, la que muestra mayor cobertura espacial de resultados estadísticamente significativos es la DTR. Entre los principales resultados se obtiene el descenso (aumento) de los valores medios de DTR durante la fase NAO negativa (positiva), aunque no hay cambios importantes en las correlaciones entre variables dependiendo de las fases de la NAO. En términos generales, y durante la fase NAO negativa (positiva), se produce un aumento (descenso) de la covariabilidad de temperaturas y precipitaciones en las estaciones occidentales, mientras que el comportamiento opuesto se detecta en las estaciones del litoral mediterráneo.

Ohm : Obradoiro de Historia Moderna, 2016

Desde el siglo XVIII la Meteorología se desarrolla en España bajo el amparo del pensamiento ilust... more Desde el siglo XVIII la Meteorología se desarrolla en España bajo el amparo del pensamiento ilustrado y el impulso de otras disciplinas, como la ciencia agraria, la navegación a vela y la medicina. El objetivo de este trabajo es ilustrar el desarrollo de la Meteorología usando como ejemplo un conjunto de estudios de carácter médico que, desde Andalucía, se publican en el periodo 1754-14852. Se analizan las contribuciones de Nieto de Piña al estudio del clima de Sevilla en la década de los 1780, de Juan Manuel de Aréjula sobre el clima de Cádiz en los últimos años del siglo y hasta 1803, y de la Sociedad Médico-Quirúrgica de Cádiz durante el periodo 1820-1824. Finalmente, en la topografía médica de Málaga (1852), ya se reconoce que la Meteorología y la Medicina son disciplinas distintas, con objetivos y métodos diferentes, pero aún complementarias.

Climate of the Past Discussions, 2014

The Sahel is the semi-arid transition zone between arid Sahara and humid tropical Africa, extendi... more The Sahel is the semi-arid transition zone between arid Sahara and humid tropical Africa, extending approximately 10–20° N from Mauritania in the West to Sudan in the East. The African continent, one of the most vulnerable regions to climate change, is subject to frequent droughts and famine. One climate challenge research is to isolate those aspects of climate variability that are natural from those that are related to human influences. Therefore, the study of climatic conditions before mid-19th century, when anthropogenic influence was of minor importance, is very interesting. In this work the frequency of extreme events, such as droughts and floods, in Western Sahel from the 16th to 18th centuries is investigated using documentary data. Original manuscripts with historical chronicles from Walata and Nema (Mauritania), Timbuktu and Arawan (Mali), and Agadez (Niger) have been analyzed. Information on droughts, intense rainfall, storms and floods, as well as socioeconomic aspects (f...

Detecting and Modelling Regional Climate Change, 2001

Singular Spectral Analysis (SSA) is a tool for time series analysis whose purpose is to identify ... more Singular Spectral Analysis (SSA) is a tool for time series analysis whose purpose is to identify temporal patterns that explain a high proportion of the total variance of the series. The test Monte Carlo-SSA is used in two different situations: (i) in a simple hypothetical noise model, where the data consist of white or red noise; and (ii) in a composite hypothetical noise model, assuming some deterministic components, such as trends or annual cycles, already found in the data. In this case, it is necessary to examine whether or not the remainder components can be attributed to noise.