17 research outputs found
Data quality control and homogenization of air temperature and precipitation series in the area of the Czech Republic in the period 1961–2007
Quality control and homogenization has to be undertaken prior to any data analysis in order to eliminate any erroneous values and non climatic biases in time series. In this work we describe and then apply our own approach to data quality control, combining several methods: (i) by applying limits derived from interquartile ranges (ii) by analyzing difference series between candidate and neighbouring stations and (iii) by comparing the series values tested with "expected'' values &ndash; technical series created by means of statistical methods for spatial data (e.g. IDW, kriging). <br><br> Because of the presence of noise in series, statistical homogeneity tests render results with some degree of uncertainty. In this work, the use of various statistical tests and reference series made it possible to increase considerably the number of homogeneity test results for each series and thus to assess homogeneity more reliably. Inhomogeneities were corrected on a daily scale. <br><br> These methodological approaches are demonstrated by use of the daily data of air temperature and precipitation measured in the area of the Czech Republic. Series were processed by means of developed ProClimDB and AnClim software (<a href="http://www.climahom.eu" target="_blank">http://www.climahom.eu</a>)
Quality control and homogenization of daily meteorological data in the trans-boundary region of the Jhelum River basin
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The 1921 European drought: impacts, reconstruction and drivers
The European drought of 1921 is assessed in terms of its impacts on society and in terms of its physical characteristics. The development of impacts of the drought are categorized by a systematic survey of newspaper reports from five European newspapers covering the area from England to the Czech Republic and other parts of Europe. This is coupled to a reconstruction of daily temperature and precipitation based on meteorological measurements to quantify the drought severity and extent, and reanalysis data are used to identify its drivers. This analysis shows that the first impacts of the drought started to appear in early spring and lingered on until well into autumn and winter, affecting water supply and agriculture and livestock farming. The dominant impact in western Europe is on agriculture and livestock farming while in central Europe the effects of wildfires were reported on most often. The peak in the number of reports is in late summer. Preceding the first impacts was the dry autumn of 1920 and winter 1920–1921. The area hardest hit by the drought in the following spring and summer was the triangle between Brussels, Paris and Lyon, but a vast stretch of the continent, from Ireland to the Ukraine, was affected. The reported impacts on water supply and water-borne transport in that region were matched by an analysis of the hydrological situation over the Seine catchment. On average, the 1921 summer was not particularly hot, but the heatwave which was observed at the end of July saw temperatures matching those of the heatwaves in modern summers. Similar to modern droughts, an anticyclone was present roughly over the British Isles, maintaining sunny and dry weather in Europe and steering away cyclones to the north. Its persistence makes it exceptional in comparison to modern droughts.
The 1921 drought stands out as the most severe and most widespread drought in Europe since the start of the 20th century. The precipitation deficit in all seasons was large, but in none of the seasons in 1920 and 1921 was the precipitation deficit the largest on record. The severity of the 1921 drought relates to the conservative nature of drought which amplifies the lack of precipitation in autumn and winter into the following spring and summer
Reflections of global warming in trends of temperature characteristics in the Czech Republic, 1961–2019
Drought stress impact on vegetable crop yields in the Elbe River lowland between 1961 and 2014
The study is focused on drought stress that is detrimental to yield formation of field-grown vegetables in the lowland regions of the Czech Republic. Extensive vegetable yield losses are attributed to drought, often in combination with heat or other stresses. The objective of this research was to investigate, under field conditions, the effect of drought stress quantified by the Standardized Precipitation Evapotranspiration Index (SPEI) on yield variability of key vegetable crops growing in the Elbe River lowland, representing central European agriculture conditions. Additionally, we also tried to determine the period of crop with the highest sensitivity to drought (PCSD) of vegetable crops over the Elbe River lowland. Historical climate datasets for a regular gridded network with a high horizontal resolution of 10 km (CZGRIDS) and 305 climatological stations from the Czech Hydrometeorological Institute were applied. The SPEI at 1-, 3-, and 6-month lags was calculated for the period 1961-2014 based on precipitation and input dataset for the reference evapotranspiration (ETr) by the Penman-Monteith (PM) method. Moreover, the difference between daily precipitation and crop evapotranspiration (ETc) has been used to calculate the mean crop water balance (D) per main growth stages, as an indicator of plant stress. This improvement increased the applicability of the SPEI in agriculture drought impact on rainfed and/or irrigated field crops grown under various agronomic management systems. To understand how the SPEI, over the period 1989-2014, controlled the yield variation, we calculated the percentage of yield losses and gains for each crop. When the value of SPEI at 3-month lag–as a measure of the balance between the water availability and the atmospheric water demand–for PCSD was between -1.49 and 0.99, the yield moderately increased for Fruiting vegetables (e.g. tomatoes, cucumber). Conversely, when the SPEI-3 in the key development stage dropped below -3.0, the yield losses were about -30% and a negative influence is apparent from threshold of the SPEI≤-1.5. The effect of the SPEI on yield formation of vegetable cultivars grown under filed conditions was achieved up to 62% in the study region.El estudio se centra en los perjuicios causados por las sequías sobre los cultivos en las regiones bajas de la República Checa. Grandes pérdidas en los cultivos se han atribuido a las sequías, a menudo en combinación con el calor y otros tipos de estress. El objetivo de este trabajo fue investigar el efecto de las sequías cuantificado mediante el Índice de Precipitación Evapotranspiración estandarizada (SPEI) sobre la variabilidad de la producción de cultivos clave en las tierras bajas del río Elba. Se utilizaron bases climáticas históricas para una cuadrícula de alta resolución horizontal de 10 km y 305 estaciones climatológicas del Instituto Hidrometeorológico Checo. Se calculó el SPEI para intervalos de 1, 3 y 6 meses en el periodo 1961-2014, basado en la precipitación y en la evapotranspiración de referencia (ET) utilizando el método de Penman-Monteith. Además, la diferencia entre la precipitación diaria y la evapotranspiración del cultivo se ha utilizado para calcular el balance medio del cultivo (D) para los principales estadios del crecimiento, como un indicador de estress de las plantas. Esta mejora metodológica aumentó la aplicabilidad del SPEI en el impacto agrícola de la sequía sobre cultivos de secano y/o regadío bajo diferentes sistemas de gestión agronómica. Para comprender cómo controla el SPEI la variación de la producción, calculamos el porcentaje de pérdidas y ganancias para cada cultivo. Cuando el valor del SPEI en un plazo de tres meses (como medida del balance entre la disponibilidad de aguay la demanda atmosférica de agua) estaba entre 1,49 y 0,99, la producción aumentaba moderadamente en el caso de las plantas de fruto (por ej., tomates, pepinos). Por el contrario, cuendo el SPEI-3 descendió por debajo de -3,0 en un estadio clave de desarrollo, las pérdidas de producción fueron de alrededor del 30%, y una influencia negativa fue apreciable a partir de un umbral de SPEI<1,5