Zbigniew Ustrnul

Classifications of Atmospheric Circulation Patterns

We review recent advances in classifications of circulation patterns as a specific research area within synoptic climatology. The review starts with a general description of goals of classification and the historical development in the field. We put circulation classifications into a broader context within climatology and systematize the varied methodologies and approaches. We characterize three basic groups of classifications: subjective (also called manual), mixed (hybrid), and objective (computer‐assisted, automated). The roles of cluster analysis and principal component analysis in the classification process are clarified. Several recent methodological developments in circulation classifications are identified and briefly described: the introduction of nonlinear methods, objectivization of subjective catalogs, efforts to optimize classifications, the need for intercomparisons of classifications, and the progress toward an optimum, if possible unified, classification method. Among the recent tendencies in the applications of circulation classifications, we mention a more extensive use in climate studies, both of past, present, and future climates, innovative applications in the ensemble forecasting, increasing variety of synoptic–climatological investigations, and steps above from the troposphere. After introducing the international activity within the field of circulation classifications, the COST733 Action, we briefly describe outputs of the inventory of classifications in Europe, which was carried out within the Action. Approaches to the evaluation of classifications and their mutual comparisons are also reviewed. A considerable part of the review is devoted to three examples of applications of circulation classifications: in historical climatology, in analyses of recent climate variations, and in analyses of outputs from global climate models.

TRENDS OF MAXIMUM AND MINIMUM DAILY TEMPERATURES IN CENTRAL AND SOUTHEASTERN EUROPE

Changes in maximum and minimum daily temperatures (TMAX and TMIN, respectively) in nine selected regions of central Europe and in Bulgaria during 1951–1990 are investigated. Average series for central Europe are compiled and analyzed by linear trend analysis and the kernel smoothing. The increase in the annual TMAX in central Europe was, during 1951–1990, slightly lower than that of TMIN (0ċ52°C and 0ċ60°C, respectively). This results in a small decrease in the daily temperature range (DTR) by −0ċ08°C. With the exception of the spring TMIN other linear trends are insignificant. The observed insignificant trends in DTR in the central European region are related to small cloudiness changes. Long-term fluctuations of annual TMAX, TMIN, and DTR for eight selected series during the twentieth century are also investigated.

Plutonium isotopes in the atmosphere of Central Europe: Isotopic composition and time evolution vs. circulation factors

This paper reports evidence of Pu isotopes in the lower part of the troposphere of Central Europe. The data were obtained based on atmospheric aerosol fraction samples collected from four places in three countries (participating in the informal European network known as the Ring of Five (Ro5)) forming a cell with a surface area of about 200,000km(2). We compared our original data sets from Krakow (Poland, 1990-2007) and Bialystok (Poland, 1991-2007) with the results from two other locations, Prague (Czech Republic; 1997-2004) and Braunschweig (Germany; 1990-2003) to find time evolution of the Pu isotopes. The levels of the activity concentration for (238)Pu and for ((239+240))Pu were estimated to be a few and some tens of nBqm(-3), respectively. However, we also noted some results were much higher (even about 70 times higher) than the average concentration of (238)Pu in the atmosphere. The achieved complex data sets were used to test a new approach to the problem of solving mixing isotopic traces from various sources (here up to three) in one sample. Results of our model, supported by mesoscale atmospheric circulation parameters, suggest that Pu from nuclear weapon accidents or tests and nuclear burnt-up fuel are present in the air.

Late Spring Freezes in Poland in Relation to Atmospheric Circulation

Abstract Late spring freeze events, a significant agroclimatic hazard, are investigated for Poland. Daily minimum air temperatures from 184 stations for the period 1951-2010 were used to analyze the frequency and conditional probability of late spring freezes. In addition, three classification schemes were employed to investigate the atmospheric circulation responsible for late spring freezes events. The findings suggest that knowledge of the airflow influencing late spring freezes can help to understand the complex historical trends and projected future changes in freeze risk for perennial crops

Climatologically based warning system against meteorological hazards and weather extremes: the example for Poland

AbstractThis work presents a detailed scientific concept of an operational warning system concerning weather hazards, which is a component of the IT System for Country’s Protection against extreme hazards currently under development in Poland. The system displays eight weather hazards that prevail in Poland (air temperature extremes, heavy rainfall, strong wind, intensive snowfall, fog, glaze, rime, and thunderstorms with hail), which are presented on the maps. The information will also be made available to the public in the form of warnings sent automatically via the Internet or text messages. The weather hazard maps consist of two highly complementary components. The first contains maps of areas vulnerable to the hazards’ occurrence (climatological maps). These are based on observational and measurement data covering the period of 1951/1966–2010. The second component consists of operational maps based on current weather conditions, including primarily predictive data provided by the mesoscale numerical weather prediction model ALADIN (warning maps). The climatological information has been applied to the operational maps for several extremes not directly predicted by the ALADIN model.

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.

Long-term variability of air temperature and precipitation conditions in the Polish Carpathians

Mountain regions are sensitive to climate changes, which make them good indicators of climate change. The aim of this study is to investigate the spatial and temporal variability of air temperature and precipitation in the Polish Carpathians. This study consists of climatological analyses for the historical period 1851-2010 and future projections for 2021-2100. The results confirm that there has been significant warming of the area and that this warming has been particularly pronounced over the last few decades and will continue in the oncoming years. Climate change is most evident in the foothills; however, these are the highest summits which have experienced the most intensive increases in temperature during the recent period. Precipitation does not demonstrate any substantial trend and has high year-to-year variability. The distribution of the annual temperature contour lines modelled for selected periods provides evidence of the upward shift of vertical climate zones in the Polish Carpathians, which reach approximately 350 meters, on average, what indicates further ecological consequences as ecosystems expand or become extinct and when there are changes in the hydrological cycle.