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During cold winter nights we often hear the question "where is the global warming, should it not be warmer?". Low temperatures that can still be recorded in the Banat Plain during winter or media reports of cold waves affecting various regions worldwide seem to the common man to be in total contradiction with the concerns of the scientific community about global warming. With this article we are trying to follow the evolution of some meteorological parameters that can affect the population in one way or another, namely number of tropical days, number of winter days, number of tropical nights, number of frosty nights, absolute maximum and minimum temperatures. Thus, the data obtained from the three national meteorological services (Romanian, Hungarian, and Serbian) operating on the territory of the Banat Plain were grouped in a common database and analyzed both in Excel and with the help of the non-parametric Mann-Kendall test, obtaining a series of conclusions on the evolution of the abovementioned parameters, as well as on the way how the increase in the risk of high temperatures is compensated (or not) by the decrease in the risk of low temperatures. [ABSTRACT FROM AUTHOR]

The Eastern part of Uttar Pradesh regularly faces the problem of a severe flood. This study is mainly concerned about the trend of rainfall in the Eastern Plain Zone (EPZ) of Uttar Pradesh. Data for the period 1981-2017 were collected on yearly and monthly basis to calculate annual and seasonal rainfall trend and variation. Mann-Kendall (MK) test was used together with the Sen's Slope Estimator for the determination of trend and slope magnitude. South West (SW) monsoon has the highest share in the annual rainfall. Annual rainfall followed the same trend of SW monsoon, which is increasing over the period. North East (NE) monsoon and winter rainfall indicated decreasing trend over the years, whereas summer rainfall exhibited a significant increase. NE monsoon, winter rainfall and summer rainfall revealed more variation compared to SW monsoon and annual rainfall. [ABSTRACT FROM AUTHOR]

Climate warming influences highly on snow cover regime in the midlatitudes. Snow cover conditions, in turn, affect human activity very much. The aim of this study was (a) to analyse spatial and temporal variability of snow cover duration, (b) to analyse spatial and temporal variability of the start and end dates of the period with the permanent snow cover, (c) to describe spatial, temporal and seasonal variability of median and maximum snow depth in Estonia and (d) to determine the presence of long-term changes and trends in these parameters during the period 1950/51–2015/16. Time series of daily snow depth at 22 stations for that period were processed in order to obtain reliable estimates of changes in the snow regime. Snow cover data are non-normally distributed, therefore, median and quartile range were used to describe the mean state and variability of snow cover. Only these dates were included into the analysis when snow cover was observed at least on 50% of days in the time series. Trend analysis was made using the Mann-Kendall test and trend values were found using the Theil-Sen's method. A large spatio-temporal variability of snow cover duration was found. The median number of days with snow cover at the 22 stations was 112, varying between 61 and 130 days. In the coastal regions of Estonia and especially on the western coast of Saaremaa Island snow cover duration has been much lower than in the continental part. The longest snow cover period is observed on uplands in south-eastern and north-eastern Estonia. It was found that, in the average, the period with the permanent snow cover in the continental Estonia begins on 19 December and ends on 18 March. There was a negative trend in snow cover duration due to the earlier snow melting in spring at the majority of stations. The end date of the permanent snow cover has shifted earlier by 10–30 days in 66 years and its duration has decreased accordingly. The maximum snow depth has been recorded on uplands of south-eastern Estonia with the median value 38 cm. There was a decreasing multiannual trend in snow depth from January to the end of March. Changes in snow depth were largest in the end of February and in March when the trend was statistically significant. In the average, snow depth has decreased by 0.5–1.5 cm per decade, i.e. by 2–9 cm throughout the whole study period. [ABSTRACT FROM AUTHOR]

The interannual and decadal variability and trends of winter (December to February) air temperature over the Oltenia Plain area is analysed for the period 1961 to 2010. The datasets cover monthly temperatures from six meteorological stations. The variability of the temperature data was analysed by means of standard deviation, the mean of three distinct sub-periods (1961-1990, 1971-2000, 1981-2010), as well as the mean of ten-year intervals. Linear regression and the non-parametric Mann-Kendall test were used to emphasize any trends present in the datasets. From the temporal variations viewpoint, an increase in temperature is observed particularly in the third and fourth decades, as the average values for the last decade mark a slight decrease in temperature. From the spatial distribution viewpoint, the most significant positive deviations characterize the northern and western part of the plain. Mann-Kendall test illustrates a monotonic upward trend all over the analysed region, but the results are not statistically significant except for the aforementioned parts of the plain for the entire winter season and February. [ABSTRACT FROM AUTHOR]

The local hydrological, agricultural and economic activities heavily depend on micro-level rainfall. Therefore, this study examines trends and variability of rainfall in Uttarakhand state of western Himalaya, India. The season and station-wise results of this study differ from India level results. The annual rainfall declined in high altitudes. Similarly, the monsoon rains declined in high altitudes and increased in low altitudes, whereas winter rainfall show mixed trends. The variability of monsoon rainfall was lowest for all stations and seasons, while the winters show low variability. Inter-seasonal variability is recorded highest in plains and lowest in high altitudes. [ABSTRACT FROM AUTHOR]

This study presents the first comprehensive nationwide trend detection of streamflow in Nepal, a country that has been historically understudied despite its critical location as the southern pathway for most of the Himalayan snowpack melt and torrential seasonal monsoon rains. We applied Mann-Kendall and Sen's trend tests using trend-free pre-whitening and bootstrap approaches to two streamflow data sets to deal with serial and cross-correlation. The two data sets comprised 23–33 hydrometric stations with 31 years and more than 20 years of published data, respectively. The test on the 33 stations data set showed that 23% of the streamflow variables studied had statistically significant trends, evenly divided between upward and downward trends. Similarly, in the second, relatively smaller data set, 24% of variables exhibited trends, of which 41% were downward and 59% upward. The higher percentage of observed upward trends in pre-monsoon and winter seasonal average flow is noteworthy given the potential snowmelt contribution in many of the studied sites. Trends were mostly absent in stations draining the larger basins. However, some spatial patterns were seen in the observed trend directions, specifically, a downward trend in the Karnali-Mahakali River basin and an upward trend in the West Rapti River basin, as well as a nationwide absence of trend in the post-monsoon season. Editor Z.W. Kundzewicz Citation Gautam, M.R. and Acharya, K., 2011. Streamflow trends in Nepal. Hydrological Sciences Journal, 57 (2), 344–357. [ABSTRACT FROM PUBLISHER]

The article presents a study on the trends in timing of low flows in Canada for Reference Hydrometric Basin Network based on independence, short-term persistence (STP), and long-term persistence (LTP). The study examines the timing of low flows during summer and winter, and uses Mann-Kendall trend test and numerical analysis. The study shows that timing of summer low flow changed toward the later dates in western Canada, while timing of winter low flow was dominant in earlier dates over Canada.

Precipitation is considered to be a very important climatic element for the plain areas in Romania. Thus, variation in precipitation data ranges is more and more studied. In this paper total amounts of precipitation and the depth of the snow cover were analyzed. Annual, seasonal and monthly data were used to identify the general trends in the amount of precipitation for a period of 41 years (1965-2005) in 5 weather stations from the central part of Romanian Plain: Alexandria, Piteşti, Ro Fiorii de Vede, Turnu Măgurele and Videle. They are located in different areas: on the high plain in the North of the region, in the central area and on the Danube River banks. For snow cover only winter months series were analyzed. To detect and estimate trends in the time series, Mann-Kendall test for trend and Sen's slope estimates were used while for fluctuations in precipitations WASP cumulated curve was analyzed. Main conclusions that can be mentioned are: decreasing trends in total amounts of precipitation, especially for summer months and for annual values, but also with fluctuations that had upward trends in the first part of the analyzed period and than decreasing trends beginning with October 1981; increasing trends of the snow cover during winter months. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the trends in daily rainfall in the Iberian Peninsula from 1951 to 2002. It examines the annual and seasonal variations in total precipitation, precipitation intensity, number of wet days, and percentage of rain falling on days above the 95th percentile from daily precipitation records in 22 sites. Results of the study show a decrease in the daily intensity of rainfall and a decreasing trend in precipitation intensity in winter and annual series for some localities.