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Vargas A.,University of Barcelona | Arnold D.,Central Institute for Meteorology and Geodynamics ZAMG | Adame J.A.,El Arenosillo National Institute For Aerospace Technology Inta | Grossi C.,Catalan Institute of Climate Science IC3 | And 2 more authors.
Journal of Environmental Radioactivity | Year: 2015

This paper presents an analysis of one year of hourly radon and meteorological measurements at 10m and 100m a.g.l. at El Arenosillo tall-tower station, in the south-west of the Iberian Peninsula. Whole-year and seasonal composites of the diurnal radon cycle show the expected behaviour, with larger concentrations at 10m than at 100m during the night, due to poor vertical mixing, and similar concentrations at both heights during the daylight hours. Wind speed and wind direction analyses by sector show the prevailing contributions for each season. Sectors with air which has spent a longer period over the ocean and high wind speeds will lead to low concentrations at both levels, whereas inland sectors show a clear increase of the concentrations with similar overall averages for the two levels. The Sierra Morena, Guadalquivir and Bethics System sectors (continental pathways) are the sectors that show higher concentrations for mild to large wind speeds. The daily evolution of radon concentration differences at both heights has been grouped into four clusters by using a K-means algorithm method. The four clusters have been selected so that they sufficiently describe different characteristics in terms of stability. The temporal evolution of the mixing height (MH) and of the bulk diffusivity parameter (Kb) during the nocturnal period has been calculated by using the temporal variation of 222Rn concentration at 10m and the concentration gradient with height, respectively. © 2014 Elsevier Ltd.

van den Hurk B.,Royal Netherlands Meteorological Institute | Doblas-Reyes F.,Catalan Institute of Climate Science IC3 | Doblas-Reyes F.,ECMWF | Balsamo G.,ECMWF | And 3 more authors.
Climate Dynamics | Year: 2012

The Second Global Land Atmosphere Coupling Experiment (GLACE2) is designed to explore the improvement of forecast skill of summertime temperature and precipitation up to 8 weeks ahead by using realistic soil moisture initialization. For the European continent, we show in this study that for temperature the skill does indeed increase up to 6 weeks, but areas with (statistically significant) lower skill also exist at longer lead times. The skill improvement is smaller than shown earlier for the US, partly because of a lower potential predictability of the European climate at seasonal time scales. Selection of extreme soil moisture conditions or a subset of models with similar initial soil moisture conditions does improve the forecast skill, and sporadic positive effects are also demonstrated for precipitation. Using realistic initial soil moisture data increases the interannual variability of temperature compared to the control simulations in the South-Central European area at longer lead times. This leads to better temperature forecasts in a remote area in Western Europe. However, the covered range of forecast dates (1986-1995) is too short to isolate a clear physical mechanism for this remote correlation. © 2010 The Author(s).

Dominguez-Castro F.,University of Extremadura | Vaquero J.M.,University of Extremadura | Rodrigo F.S.,University of Almeria | Farrona A.M.M.,Complutense University of Madrid | And 7 more authors.
International Journal of Climatology | Year: 2014

ABSTRACT: This article summarizes recent efforts on early instrumental data recovery in Spain conducted under the Salvà-Sinobas project. We have retrieved and digitized more than 100000 meteorological observations prior to 1850 in Spain. This data set contains measurements of air temperature, atmospheric pressure, wind direction and state of the atmosphere in 16 places located in Iberia and the Balearic Islands. Most of the observations are made on a daily basis. However, monthly and annual information has also been retrieved. The time coverage of the series is not homogeneous, with the earliest records starting in Seville in 1780. Prior to this work only two series were available in Spain (i.e. Cadiz and Barcelona), so this data set represents a great advance in the early data availability for Spain. Due to the lack of metadata in most of the series, their interpretation must be made with caution. © 2013 Royal Meteorological Society.

Marce R.,Catalan Institute for Water Research | Obrador B.,University of Barcelona | Morgui J.-A.,University of Barcelona | Morgui J.-A.,Catalan Institute of Climate Science IC3 | And 3 more authors.
Nature Geoscience | Year: 2015

Most lakes and reservoirs have surface CO2 concentrations that are supersaturated relative to the atmosphere. The resulting CO2 emissions from lakes represent a substantial contribution to the continental carbon balance. Thus, the drivers of CO2 supersaturation in lakes need to be understood to constrain the sensitivity of the land carbon cycle to external perturbations. Carbon dioxide supersaturation has generally been attributed to the accumulation of inorganic carbon in lakes where respiration exceeds photosynthesis, but this interpretation has faced challenges. Here we report analyses of water chemistry data from a survey of Spanish reservoirs that represent a range of lithologies, using simple metabolic models. We find that, above an alkalinity threshold of 1 mequiv. l-1, CO2 supersaturation in lakes is directly related to carbonate weathering in the watershed. We then evaluate the global distribution of alkalinity in lakes and find that 57% of the surface area occupied by lakes and reservoirs - particularly in tropical and temperate latitudes - has alkalinity exceeding 1 mequiv. l-1. We conclude that lake inputs of dissolved inorganic carbon from carbonate weathering should be considered for the CO2 supersaturation of lakes at both regional and global scales. © 2015 Macmillan Publishers Limited. All rights reserved

Stewart-Ibarra A.M.,New York University | Lowe R.,Catalan Institute of Climate Science IC3
American Journal of Tropical Medicine and Hygiene | Year: 2013

We report a statistical mixed model for assessing the importance of climate and non-climate drivers of interannual variability in dengue fever in southern coastal Ecuador. Local climate data and Pacific sea surface temperatures (Oceanic Niño Index [ONI]) were used to predict dengue standardized morbidity ratios (SMRs; 1995-2010). Unobserved confounding factors were accounted for using non-structured yearly random effects. We found that ONI, rainfall, and minimum temperature were positively associated with dengue, with more cases of dengue during El Niño events. We assessed the influence of non-climatic factors on dengue SMR using a subset of data (2001-2010) and found that the percent of households with Aedes aegypti immatures was also a significant predictor. Our results indicate that monitoring the climate and non-climate drivers identified in this study could provide some predictive lead for forecasting dengue epidemics, showing the potential to develop a dengue early-warning system in this region. Copyright © 2013 by The American Society of Tropical Medicine and Hygiene.

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