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Global changes in climate have been widely documented but the relationships between these changes and floods are not easy to establish. Hydroclimatology offers an important tool in order to improve our knowledge about the flood producing mechanisms, which can be used to explain historical and palaeohydrological events. Storm cells and mesoscale systems develop into small floods, mainly at tributary streams. But a synoptic scale relates better to Guadiana River floods, dominant in winter. At a higher level, macroscale atmospheric configuration can also explain flood generation at the Guadiana River and, particularly, the North Atlantic Oscillation (NAO) that is one of the most important recurrent patterns of atmospheric circulation. There is no reliable evidence, however relating NAO and historical floods in Europe, especially for central European countries. This situation changes in the Iberian Peninsula, specially in the Southwest that shows a good relationship between winter floods and a negative NAO phase. Recent Guadiana River floods (XX century) could be related to these phenomena, but there´s not and index who covers previous events. Guadiana palaeoflood records compiled using slackwater deposits are dated by 14C radiometric methods and associated, when it is possible to a historical flood event. Results shows event clusters during cooling phases and it is likely that they reflect moments of climatic variability., Ministerio de Ciencia y Tecnología (España), Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

Monthly, seasonal and annual trends in mean temperatures have been analysed in this study using data from 37 weather stations from the Pakistan Meteorological Department with records from 1952 to 2009. Statistical tests including Sen's slope and Mann‐Kendall were applied to each of the 37 stations in order to determine the sign and slopes of trends and their statistical significance. The study reveals that the temperature has generally increased in Pakistan at all time scales analysed over the past few decades. March and the pre‐monsoon season were the periods with the highest number of weather stations showing statistical significance, and also with the highest magnitudes of trends. Mean annual temperature increased around 0.36 °C/decade. This rise in temperature is slightly higher than other results found for Pakistan. The association between temperatures and certain teleconnection patterns, as well as the influence of the urban effect, might be among the causes of the trends found in this study. The largest number of correlations between mean temperatures and teleconnection patterns was found in March, April and May with NAO, ENSO and NCP, respectively. The North Atlantic Oscillation (NAO) may also have an influence on the temperatures of certain months in the monsoon season and particularly in August. At a seasonal resolution, NAO and NCP may control temperatures in the pre‐monsoon season. The lowest number of sites exhibiting correlations was found in winter and in the post‐monsoon seasons., Depto. de Didáctica de las Ciencias Experimentales , Sociales y Matemáticas, Fac. de Educación, TRUE, pub

This study analyzes the mean maximum and minimum temperature trends on a monthly, seasonal, and annual timescale by applying various statistical tools to data from 476 Spanish weather stations during the period between 1961 and 2006. The magnitude of the trends was derived from the slopes of the regression lines using the least squares method, and the nonparametric Mann–Kendall test was used to determine the statistical significance of the trends. Temperature significantly increased in over 60% of the country in March, June, spring, and summer in the case of maximum temperatures and in March, May, June, August, spring, and summer for minimum temperatures. At the annual resolution, temperatures significantly increased in over 90% of Spain with a rise of around 0.3°C/decade. The maximum temperature increased at a higher rate than the minimum temperature from midsummer to early winter as well as in winter, spring, and summer and also on an annual basis., Depto. de Didáctica de las Ciencias Experimentales , Sociales y Matemáticas, Fac. de Educación, TRUE, pub

A severe hailstorm that occurred in Spain on 30 August 2022, caused material and human damage, including one fatality due to giant hailstones up to 12 cm in diameter. By applying a pseudo‐global warming approach, here we evaluate how a simultaneous marine heatwave (and anthropogenic climate change) affected a unique environment conductive to such giant hailstones. The main results show that the supercell development was influenced by an unprecedented amount of convective available energy, with significant contributions from thermodynamic factors. Numerical simulations where the marine heatwave is not present show a notable reduction in the hail‐favorable environments, related mainly to modifications in thermodynamic environment. Our simulations also indicate that the environment in a preindustrial‐like climate would be less favorable for convective hazards and thus the hailstorm event would likely not have been as severe as the observed one, being possible to perform a novel attribution of such kind., Polish National Science Centre, Instituto de Matemática Interdisciplinar (UCM), ECMWF Special Project SPESMART, Ministerio de Ciencia e Innovación (España), Ministerio de Economía y Competitividad (España), Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Referencias bibliográficas: • Abbas F. Analysis of a historical (1981-2010) temperature record of the Punjab province of Pakistan. Earth Interact. 2013, 17:1-21. (Paper No. 15). • Afzal M., Haroon M.A., Rana A.S., Imran A. Influence of North Atlantic Oscillations and Southern Oscillations on winter precipitation of Northern Pakistan. Pak. J. Meteorol. 2013, 9(18):1-8. • Ahmad W., Fatima A., Awan U.K., Anwar A. Analysis of long term meteorological trends in the middle and lower Indus basin of Pakistan-a non-parametric statistical approach. Glob. Planet. Change 2014, 122:282-291. 10.1016/j.gloplacha.2014.09.007. • Almazroui M., Dambul R., Islam M.N., Jones P.D. Atmospheric circulation patterns in the Arab region and its relationships with Saudi Arabian surface climate: a preliminary assessment. Atmos. Res. 2015, 161-162:36-51. 10.1016/j.atmosres.2015.03.014. • Bapuji Rao B., Santhibhushan Chowdary P., Sandeep V.M., Rao V.U.M., Venkateswarlu B. Rising minimum temperature trends over India in recent decades""": implications for agricultural production. Glob. Planet. Change 2014, 117:1-8. 10.1016/j.gloplacha.2014.03.001. • Bartholomew H., Jin M. ENSO effects on land skin temperature variations: a global study from satellite remote sensing and NCEP/NCAR reanalysis. Climate 2013, 1:53-73. 10.3390/cli1020053. • Bhutiyani M.R., Kale V., Pawar N.J. Long-term trends in maximum, minimum and mean annual air temperatures across the Northwestern Himalaya during the twentieth century. Clim. Chang. 2007, 85(1-2):159-177. 10.1007/s10584-006-9196-1. • Bocchiola D., Diolaiuti G. Recent (1980-2009) evidence of climate change in the upper Karakoram, Pakistan. Theor. Appl. Climatol. 2013, 113(3-4):611-641. 10.1007/s00704-012-0803-y. • Braganza K., Karoly D.J., Arblaster J.M. Diurnal temperature range as an index of global climate change during the twentieth century. Geophys. Res. Lett. 2004, 31:L13217. 10.1029/2004GL019998. • Brunetti M., Kutiel H. The relevance of the North-Sea Caspian P, Data from 37 weather stations with records of maximum and minimum temperatures (Tmax and Tmin hereafter) were used to analyse trends in both variables at a monthly, seasonal and annual resolution. Sen's slope and Mann–Kendall statistical tests were applied to calculate the sign and slopes of trends and their statistical significance. A correlation analysis was also performed to study possible relationships between temperatures and certain teleconnection patterns with an influence on Northern Hemisphere temperatures: the North Atlantic Oscillation (NAO), Arctic Oscillation (AO), El Niño-Southern Oscillation (ENSO), and North Sea Caspian Pattern (NCP). The study reveals that Tmax has significantly increased (in over 30% of sites) in the pre-monsoon season and yearly. The sharpest increases were observed in March. Tmin clearly showed positive trends in the pre-monsoon season and at the annual scale. It is also worth noting a cooling trend in the northern areas during the study period. Tmax increased faster than Tmin in the northern areas in all the seasons studied and at annual resolution, while the opposite occurred in the rest of the country (except in the pre-monsoon season). The highest correlation coefficients between patterns and Tmax and Tmin were seen in the months of the pre-monsoon season: with NAO from January to March; with ENSO in May and with NCP in the late pre-monsoon season (May). AO was the pattern with the lowest relationships with temperatures. These results could have a significant influence on agriculture and water resources in Pakistan if these trends are maintained in the future., Depto. de Didáctica de las Ciencias Experimentales , Sociales y Matemáticas, Fac. de Educación, TRUE, pub

Understanding how the interactions between solar UV radiation and climate will affect leaf litter decomposition is fundamental to predict how soil and ecosystem biogeochemical cycles will respond to ongoing climate change. We carried out a manipulative experiment to investigate how UV radiation and its interaction with increased temperature (3 C on average) and a ~35% reduction in precipitation affect the decomposition of “standing” and “on the ground” litter of Stipa tenacissima, a dominant species in semiarid Mediterranean grasslands. UV radiation was manipulated using specially designed screens that either passed or blocked 90% of the UV radiation. All climate change manipulation treatments decreased litter decomposition compared to the control treatment. In particular, litter decay rates were reduced by a 34%, 43% and 62% in the rainfall reduction (RE), warming (W), and the combination of warming and rainfall reduction (WRE) treatments, respectively, compared to the control treatment. Across climate manipulation treatments, higher decay rates were observed in litter exposed to UV radiation than in litter non-exposed to UV radiation, and in litter placed on the ground than in standing litter. However, significant interactions were found between climate manipulation and UV exposure or position treatments. In the control and RE treatments, litter on the ground decomposed 25% faster than standing litter. In theWand WRE treatments, litter decomposition rates increased by 29% when exposed to UV radiation despite lower overall decay rates were observed in these treatments. Overall, lignin losses were parallelled by increases in soluble cell materials, particularly when litter was exposed to UV radiation. Our results indicate that predicted climate change scenarios will likely reduce leaf litter decomposition rates, while enhancing the relative contribution of photodegradation to overall litter decomposition in dry perennial Mediterranean grasslands., Consejo Europeo de Investigación. 7º Programa Marco de Investigación, Ministerio de Economía y Competitividad (MINECO), Depto. de Biodiversidad, Ecología y Evolución, Fac. de Ciencias Biológicas, TRUE, pub