Anita Bokwa

Seasonal Temperature and Precipitation Fluctuations in Selected Parts of Europe During the Sixteenth Century

The article in hand presents a comparative analysis of unweighted thermic and hygric index series of different European regions (northern Switzerland, Germany, the Czech Republic, northern Italy, ancient Hungary, Poland and Spain). Besides methodological aspects about the formation of indices, especially the progress as well as the question of similarity development of these series in the 16th century are discussed and shown on the balance sheet. It becomes evident that with respect to the temperature on the level of unweighted indices the European regions of Germany, the Czech Republic and Switzerland are very similar during all seasons. In winter and summer these correlations are especially evident, during the transitional seasons they are smaller. Larger differences exist between the central European core region and the adjacent areas of research. In principle, the hygric differences are larger than the thermic ones.In the course of the sixteenth century marked cooling phases occurred during all seasons with increasing accentuation. These phases were typical for the climate of the Little Ice Age. In addition to this long-term analysis, some outstanding years of extreme weather like those of 1540, 1573 and 1587 are presented, in the course of which questions of climatic impact are included. Finally, recent instrumental data was used to conduct an analysis that compared the similarities between the respective regions and the similarities between the empirical data and indices. On the one hand, this confirmed the spatial pattern, on the other hand the usability of the indices.

Global Change Research in the Carpathian Mountain Region

Abstract The Carpathian Mountains in Europe are a biodiversity hot spot; harbor many relatively undisturbed ecosystems; and are still rich in seminatural, traditional landscapes. Since the fall of the Iron Curtain, the Carpathians have experienced widespread land use change, affecting biodiversity and ecosystem services. Climate change, as an additional driver, may increase the effect of such changes in the future. Based on a workshop organized by the Science for the Carpathians network, this paper reviews the current status of global change research in the Carpathians, identifies knowledge gaps, and suggests avenues for future research.

Land Surface Temperature Patterns in the Urban Agglomeration of Krakow (Poland) Derived from Landsat-7/ETM+ Data

The aim of this study was to identify typical and specific features of land surface temperature (LST) distribution in the city of Krakow and its surroundings with the use of Landsat/ETM+ data. The paper contains a detailed description of the study area and technical properties of the Landsat program and data, as well as a complete methodology of LST retrieval. Retrieved LST records have been standardized in order to ensure comparability between satellite images acquired during different seasons. The method also enables identification of characteristic thermal regions, i.e. areas always colder and always warmer than a zonal mean LST value for Krakow. The research includes spatial analysis of the standardized LST with regard to different land cover types. Basic zonal statistics such as mean standardized LST and percentage share of hot and cold regions within 10 land cover types were calculated. GIS was used for automated data processing and mapping. The results confirmed the most obvious dependence of the LST on different land cover types. Some more factors influencing the LST were recognized on the basis of detailed investigation of the LST pattern in the urban agglomeration of Krakow. The factors are: emission of anthropogenic heat, insolation of the surfaces depending first of all on land relief and shape of buildings, seasonal changes of vegetation and weather conditions at the time of satellite image acquisition.

Daily weather observations in sixteenth-century Europe

Thirty-two weather diaries written in astronomical calendars in central Europe in the late fifteenth and sixteenth centuries are presented and discussed. Systematic weather observations were promoted by the rise of planetary astronomy and its application in astro-meteorology. The practice of keeping weather diaries spread from Cracow (Poland) to Ingolstadt (Germany) and from there to other universities. The data obtained from these sources provided the backbone for setting up series of precipitation indices for Poland, Germany and Switzerland. Monthly statistics of days with precipitation, snowfall and frost were computed by counting the relevant entries in the most important diaries. The results were compared with either those obtained from instrumental measurements in the same place or with those from modem instrumental measurements in a neighbouring place. The final results show that autumn was considerably colder in the early sixteenth century. April was considerably drier and July was wetter during the period 1508–1531 than during 1901–1960. In order to highlight the impact of weather patterns on grain prices in a year of crisis, the timing of wet and dry spells in southern Poland and southern Germany is compared for the year 1529. Winters became 1.7°C colder from 1564 to 1576 and the month of July tended to be wetter than in 1901–1960. Details noted in the diaries kept between 1585 and 1600 by the astronomers Brahe (near Copenhagen) and Fabricius (in the Ostfriesland region of northwestern Germany) closely agree. It rained more often in June and July and temperatures dropped. The winter months were more frequently dominated by winds from easterly directions, the frequency of snowfall was higher and a deficit occurred in precipitation. This points to a higher frequency of high pressure in the Fennoscandian area with cold air advection from the east or northeast.

Pre-Instrumental Weather Observations in Poland in the 16th and 17th Centuries

A few remarkable episodes can be distinguished in the European climate of the last millennium. The first is the Medieval Warm Epoch (MWE). The culmination of the MWE occurred in the 12th and 13th centuries in the period 1150-1300 (Lamb, 1982). This warm period was followed by a colder one which lasted to the second half of the 19th century and is known as the so-called Little Ice Age (LIA). The climate during the LIA was not constantly cold. The recoveries to warmer conditions in the first half of the 15th century and around 1700–1750 are evident (Lamb, 1982). They were followed by reversions to colder conditions. Some authors stress the coincidence of the two greatest periods of cooling with the two prolonged minima of sunspot activity, the Sporer Minimum from 1400 to 1510 and the Maunder Minimum from 1645 to 1715 (Schuurmans,1981; Pfister, 1994b). An increase of volcanic activity is also mentioned as a reason for the LIA. Since the second part of the 19th century the temperature has been rising although some reversions to colder conditions are also present. This warming is a global feature (Jones et al., 1986; Jones, 1994) and can be linked to an anthropogenic increase of CO2 and other greenhouse gas concentrations as well as to solar and volcanic activity variations (Schonwiese, 1984).

Influence of diversified relief on the urban heat island in the city of Kraków, Poland

In cities located in concave landforms, urban heat island (UHI) is an element of a complicated thermal structure and occurs due to the common impact of urban built-up areas and orography-induced processes like katabatic flows or air temperature inversions. Kraków, Poland (760,000 inhabitants) is located in a large valley of the river Vistula. In the years 2009–2013, air temperature was measured with the 5-min sampling resolution at 21 urban and rural points, located in various landforms. Cluster analysis was used to process data for the night-time. Sodar and synoptic data analysis provided results included in the definition of the four types of night-time thermal structure representing the highest and the lowest spatial air temperature variability and two transitional types. In all the types, there are three permanent elements which show the formation of the inversion layer, the cold air reservoir and the UHI peak zone. As the impact of land use and relief on air temperature cannot be separated, a concept of relief-modified UHI (RMUHI) was proposed as an alternative to the traditional UHI approach. It consists of two steps: (1) recognition of the areal thermal structure taking into consideration the city centre as a reference point and (2) calculation of RMUHI intensity separately for each vertical zone.

Climate Changes in the Vertical Zones of the Polish Carpathians in the Last 50 Years

The variability and extremes of air temperature and precipitation in the years 1951–2006 were analyzed for different vertical zones as well as for the W-E profile of the Polish Carpathians. Some results of the analysis were compared with those concerning the Eastern Alps. Data from 9 Polish and 18 Austrian stations were used. The variability of air temperature in the Polish Western Carpathians during the study period decreased with altitude whereas no relation between temperature variability and altitude was observed in the Alps. The rate of temperature increase per decade was much lower at Kasprowy Wierch than at the lower locations (0.14 and 0.21 K, respectively) and for the period 1956–2000 it was even statistically insignificant. Notably, the temperature at Kasprowy Wierch was much lower than the temperature at the similar altitudes in the Alps. No clear trends in precipitation can be observed in either mountain chains. The observed differences in the climate change patterns between both mountain chains are connected with their geographical features and the air temperature increase probably results from diversified effects of atmospheric circulation.