Results 1 - 10 of 3539
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[en] The paper presents the activities of radionuclides in the rain that fell in Bucharest-Magurele area on May 2nd, 1986. The artificial radionuclides measured were: Sr-89, Sr-90, Ru-103, Ru-106, Sb-125, I-131, (I+Te)-132, Cs-134, Cs-137, (Ba+La)-140, Ce-141, Ce-144, originating in the nuclear accident at Chernobyl. The activities of I-131 and Cs-137 were 28700 Bq/m2 and 3610 Bq/m2 respectively. (authors)
[en] Although the amount of 3H in Austrian precipitation is gradually approaching the natural background, the 3H concentration in samples taken by the mountain sampling station at Patscherkofel (2245 m a.s.l.) has for years been far above average. It is notable that in the neighboring valley such high amounts have not been measured. During periods of low precipitation, variations between the two stations have been most significant. Apparently, orographical situation as well as differing meteorological conditions play an important role in the level of 3H concentration in precipitation. (author) 5 figs., 5 refs
[en] In this study, we analyze spring precipitation from 92 meteorological stations spanning between 1961 and 2012 to understand temporal–spatial variability and change of spring precipitation over Southwest China. Various analysis methods are used for different purposes, including empirical orthogonal function (EOF) analysis and rotated EOF (REOF) for analyzing spatial structure change of precipitation anomaly, and the Mann–Kendall testing method to determine whether there were abrupt changes during the analyzed time span. We find that the first spatial mode of the precipitation has a domain uniform structure; the second is dominated by a spatial dipole; and the third contains five variability centers. The 2000s is the decade with the largest amount of precipitation while the 1990s is the decade with the smallest amount of precipitation. The year-to-year difference of that region is large: the amount of the largest precipitation year doubles that of the smallest precipitation year. We also find that spring precipitation in Southwest China experienced a few abrupt changes: a sudden increase at 1966, a sudden decrease at 1979, and a sudden increase at 1995. We speculate that the spring precipitation will increase gradually in the next two decades. (paper)
[en] We present a new method that allows a separation of the attribution of human influence in extreme events into changes in atmospheric flows and changes in other processes. Assuming two data sets of model simulations or observations representing a natural, or ‘counter-factual’ climate, and the actual, or ‘factual’ climate, we show how flow analogs used across data sets can provide quantitative estimates of each contribution to the changes in probabilities of extreme events. We apply this method to the extreme January precipitation amounts in Southern UK such as were observed in the winter of 2013/2014. Using large ensembles of an atmospheric model forced by factual and counterfactual sea surface temperatures, we demonstrate that about a third of the increase in January precipitation amounts can be attributed to changes in weather circulation patterns and two thirds of the increase to thermodynamic changes. This method can be generalized to many classes of events and regions and provides, in the above case study, similar results to those obtained in Schaller et al (2016 Nat. Clim. Change 6 627–34) who used a simple circulation index, describing only a local feature of the circulation, as in other methods using circulation indices (van Ulden and van Oldenborgh 2006 Atmos. Chem. Phys. 6 863–81). (letter)
[en] The aim of the study was to analyse trends and regime shifts in time series of monthly, seasonal and annual precipitation in the eastern Baltic countries (Lithuania, Latvia, Estonia) during 1966–2015. Data from 54 stations with nearly homogeneous series were used. The Mann-Kendall test was used for trend analysis and the Rodionov test for the analysis of regime shifts. Rather few statistically significant trends (p < 0.05) and regime shifts were determined. The highest increase (by approximately 10 mm per decade) was observed in winter precipitation when a significant trend was found at the large majority of stations. For monthly precipitation, increasing trends were detected at many stations in January, February and June. Weak negative trends revealed at few stations in April and September. Annual precipitation has generally increased, but the trend is mostly insignificant. The analysis of regime shifts revealed some significant abrupt changes, the most important of which were upward shifts in winter, in January and February precipitation at many stations since 1990 or in some other years (1989, 1995). A return shift in the time series of February precipitation occurred since 2003. The most significant increase in precipitation was determined in Latvia and the weakest increase in Lithuania.
[en] An analysis of spatial and temporal variations of dry spells was carried out for western Turkey using daily precipitation data of 28 stations from 1966 to 2011. Three indices and four levels of precipitation-per-day threshold were considered. Indices are number (NDS), mean length (MDS) and maximum length (MxDS) of dry spells, and the thresholds are 0.1, 1, 5 and 10 mm/day. The results showed that a general decreasing gradient from north-east to south-west is evident for NDS with exceptionally higher values at south-west at 10 mm/day threshold. Mean MDS depicts an opposite pattern to that of NDS particularly for 0.1 and 1 mm/day. Longer mean MDS values are observed at western and eastern parts for 5 and 10 mm/day. For all threshold levels, there is a clear increasing gradient from north-east to south-west for mean MxDS. Trend analysis showed that the majority of trends of the indices at all thresholds are statistically non-significant at 95% level. It can be concluded that the study area as a whole has experienced a general and slight (statistically non-significant) decreasing tendency for NDS but a general and slight (statistically non-significant) increasing tendency for MDS and MxDS. Over the same period, total annual precipitation has shown statistically non-significant decline at almost all stations. It can be concluded that the slightly decreasing tendency in total annual precipitation has been accompanied by slightly decreasing NDS and by slightly increasing MDS and MxDS. This suggests that the study area has received less precipitation and experienced less frequent but longer duration of dry spells over the period 1966–2011. The droughts in the study area have become relatively worse in terms of not only the total amount of precipitation but also duration of dry periods, although dry periods have occurred less frequently.