The paper discusses changes in the hydrological regime of high mountain Lake Morskie Oko located in the Tatra Mountains, in the Tatra Mountains National Park, a UNESCO biosphere reserve (MaB). According to the research conducted in the years 1971–2015, its water stages decreased by 3.5 cm·dec–1, mean annual water temperature increased by 0.3ºC·dec–1 and the duration of ice phenomena and ice cover was reduced by 10 day·dec–1. No considerable changes in maximum values of ice cover thickness were recorded. Such tendencies are primarily caused by long-term changes in climatic conditions – air temperature and atmospheric precipitation. The hydrological regime of the lake was also determined by changes in land use in the lake’s catchment and its location in high mountains.
Longer term monitoring of soil water content at a catchment scale is a key to understanding its dynamics, which can assist stakeholders in decision making processes, such as land use change or irrigation programs. Soil water monitoring in agriculturally dominated catchments can help in developing soil water retention measurements, for assessment of land use change, or adaptation of specific land management systems to climate change. The present study was carried out in the Pannonian region (Upper-Balaton, Hungary) on Cambisols and Calcisols between 2015 and 2021. Soil water content (SWC) dynamics were investigated under different land use types (vineyard, grassland, and forest) at three depths (15, 40, and 70 cm). The meteorological data show a continuous decrease in cumulative precipitation over time during the study with an average of 26% decrease observed between 2016 and 2020, while average air temperatures were similar for all the studied years. Corresponding to the lower precipitation amounts, a clear decrease in the average SWC was observed at all the land use sites, with 13.4%, 37.7%, and 29.3% lower average SWC for the grassland, forest, and vineyard sites, respectively, from 2016 to 2020 (measured at the 15 cm depth of the soil). Significant differences in SWC were observed between the annual and seasonal numbers within a given land use (p < 0.05). The lowest average SWC was observed at the grassland (11.7%) and the highest at the vineyard (28.3%). The data showed an increasing average soil temperature, with an average 6.3% higher value in 2020 compared to 2016. The grassland showed the highest (11.3 °C) and the forest soil the lowest (9.7 °C) average soil temperatures during the monitoring period. The grassland had the highest number of days with the SWC below the wilting point, while the forest had the highest number of days with the SWC optimal for the plants.
Biocrust sustainability relies on dew and rain availability. A study of dew and rain resources in amplitude and frequency and their evolution is presented from year 2001 to 2020 in southern Africa (Namibia, Botswana, South Africa) where many biocrust sites have been identified. The evaluation of dew is made from a classical energy balance model using meteorological data collected in 18 stations, where are also collected rain data. One observes a strong correlation between the frequency of dew and rain and the corresponding amplitudes. There is a general tendency to see a decrease in dew yield and dew frequency with increasing distance from the oceans, located west, east and south, due to decreasing RH, with a relative minimum in the desert of Kalahari (Namibia). Rain amplitude and frequency decreases when going to west and north. Short-term dew/rain correlation shows that largest dew yields clearly occur during about three days after rainfall, particularly in the sites where humidity is less. The evolution in the period corresponds to a decrease of rain precipitations and frequency, chiefly after 2010, an effect which has been cyclic since now. The effect is more noticeable towards north. An increase of dew yield and frequency is observed, mainly in north and south-east. It results in an increase of the dew contribution with respect to rain, especially after 2010. As no drastic changes in the distribution of biomass of biocrusts have been reported in this period, it is likely that dew should compensate for the decrease in rain precipitation. Since the growth of biocrust is related to dew and rain amplitude and frequency, future evolution should be characterized by either the rain cycle or, due to global change, an acceleration of the present tendency, with more dew and less rainfalls.
Brief review on the availability of General Circulation Models (GCMs) and Regional Circulation Models (RCMs) outputs for regional downscaling is presented (more in Melo, 2003; Melo, 2004). Four basic methods of regional climate change scenarios design (1st - Incremental (the simplest), 2nd - Analogue (historical or paleoclimatic), 3rd - Weather generator (artificial or based on real climatic statistics), 4th - GCMs (General Circulation Models) based) are discussed more in details. The additional one - a combined method, usually based on GCMs (mean annual/monthly warming and mean annual/monthly change in precipitation totals) and on historical analogue (statistical structure of daily/monthly data series, including physical plausibility among phenomena), was utilized in Slovakia. Finally some results of different climate change scenarios for Hurbanovo and possible user problems are listed and discussed. Special scenarios of exceptional weather events are also demanded by users, mainly from the Hydrology, Agriculture and Forestry sectors, very concise overview of such scenarios design is presented. and Príspevok prezentuje stručný prehľad dostupných modelov všeobecnej cirkulácie atmosféry (GCMs) ako aj metód na regionálnu interpretáciu výstupov GCMs. V zásade môžeme metódy konštrukcie scenárov klimatickej zmeny (zmien klímy) rozdeliť do 4 skupín: 1. Inkrementálne (prírastkové) scenáre; 2. Analógové scenáre; 3. Stochastický generátor počasia; 4. Dowscaling výstupov GCMs s regionálnou interpretáciou a využitím experimentálnych časových radov. Za piatu môžeme považovať metódu kombinovanú, ktorá využíva spoľahlivejšie scenáre na báze GCMs (zväčša teplotné a zrážkové) a pre zvyšné klimatické prvky sa pripravujú scenáre ako analógy korelačnou alebo regresnou metódou. V príspevku sú uvedené tiež príklady vybraných scenárov pre Hurbanovo.
Providing information on the impacts of climate change on hydrological processes is becoming ever more critical. Modelling and evaluating the expected changes of the water resources over different spatial and time scales can be useful in several fields, e.g. agriculture, forestry and water management. Previously a Budyko-type spatially distributed long-term climate-runoff model was developed for Hungary. This research includes the validation of the model using historical precipitation and streamflow measurements for three nested sub-catchments of the Zala River Basin (Hungary), an essential runoff contributing region to Lake Balaton (the largest shallow lake in Central Europe). The differences between the calculated (from water balance) and the estimated (by the model) mean annual evapotranspiration varied between 0.4% and 3.6% in the validation periods in the sub-catchments examined. Predictions of the main components of the water balance (evapotranspiration and runoff) for the Zala Basin are also presented in this study using precipitation and temperature results of 12 regional climate model simulations (A1B scenario) as input data. According to the projections, the mean annual temperature will be higher from period to period (2011–2040, 2041–2070, 2071–2100), while the change of the annual precipitation sum is not significant. The mean annual evapotranspiration rate is expected to increase slightly during the 21st century, while for runoff a substantial decrease can be anticipated which may exceed 40% by 2071–2100 relative to the reference period (1981–2010). As a result of this predicted reduction, the runoff from the Zala Basin may not be enough to balance the increased evaporation rate of Lake Balaton, transforming it into a closed lake without outflow.
Climate change scenarios of high quantiles of 5-day precipitation amounts (proxies for flood-generating events) over the Czech Republic are evaluated in an ensemble of high-resolution Regional Climate Model (RCM) simulations from the ENSEMBLES project. The region-of-influence method of the regional frequency analysis is applied as a pooling scheme. This means that for any single gridbox, a homogeneous region (set of gridboxes) is identified and data from that region are used when fitting the Generalized Extreme Value distribution. The climate change scenarios for the late 21st century (2070-2099) show widespread increases in high quantiles of 5-day precipitation amounts in winter, consistent with projected changes in mean winter precipitation. In summer, increases in precipitation extremes occur despite an overall drying (prevailing declines in mean summer precipitation), which may have important hydrological implications. The results for summer suggest a possible substantial change in characteristics of warm-season precipitation over Central Europe, with more severe dry as well as wet extremes. The spatial pattern of projected changes in summer precipitation extremes, with larger increases in the western part of the area and smaller changes towards east, may also point to a declining role of Mediterranean cyclones in producing precipitation extremes in Central Europe in a future climate. However, uncertainties of the climate change scenarios remain large, which is partly due to biases in reproducing precipitation characteristics in climate models, partly due to large differences among the RCMs, and partly due to factors that are poorly or not at all represented in the examined ensemble. The latter are related also to uncertainties in future emission scenarios and socio-economic development in general. and Práca analyzuje scenáre klimatickej zmeny pre vysoké kvantily 5-denných úhrnov zrážok (ktoré predstavujú možné riziko z pohľadu tvorby povodňových udalostí) na území Českej republiky, a to na základe širšej množiny simulácií z regionálnych klimatických modelov (RCM) s vysokým priestorovým rozlíšením, dostupných z projektu ENSEMBLES. Kvantily zrážkových extrémov sa odhadujú na základe metódy vplyvného regiónu, ktorá je jedným z variantov regionálnej frekvenčnej analýzy. To znamená, že pre každý gridový bod sa identifikuje jedinečný homogénny región (t.j. množina ďalších gridových bodov) a zrážkové údaje dostupné zo všetkých gridových bodov v rámci daného regiónu sa zužitkujú v procese odhadovania kvantilov využitím zovšeobecneného extremálneho rozdelenia. Scenáre klimatickej zmeny pre obdobie posledných troch dekád 21. storočia (2070-2099) naznačujú rozsiahly nárast vysokých kvantilov 5-denných úhrnov zrážok počas zimy, čo je v súlade s predpokladanými zmenami v priemerných úhrnoch zrážok za zimu. V lete sa tiež očakáva zvýšenie extrémnych úhrnov zrážok, čo môže v súvislosti s predpokladaným všeobecným úbytkom zrážok v tomto období (t.j. napriek prevažujúcemu poklesu priemerných úhrnov zrážok v lete) viesť k vážnym hydrologickým následkom. Výsledky pre leto naznačujú zásadnú zmenu v režime úhrnov zrážok v strednej Európe v teplom období roka, spojenú s častejším výskytom nepriaznivých suchých aj vlhkých extrémov. Priestorové rozdelenie predpokladaných zmien v extrémnych úhrnoch zrážok za leto - s vyšším nárastom v západných častiach skúmanej oblasti a postupne menej výrazným nárastom smerom na východ - zrejme poukazuje na slabnúcu úlohu stredomorských cyklón pri tvorbe zrážkových extrémov v strednej Európe v nastávajúcich klimatických podmienkach. Treba však podotknúť, že neurčitosť scenárov klimatickej zmeny je stále veľká, a to jednak v dôsledku nepresností v reprodukcii charakteristík úhrnov zrážok v klimatických modeloch, ďalej kvôli významným rozdielom medzi jednotlivými RCM, a nakoniec aj v dôsledku klimatických faktorov, ktoré sú slabo reprezentované, prípadne nie sú vôbec zahrnuté v analyzovanej množine výstupov klimatických modelov. Spomínané klimatické faktory takisto závisia od emisných scenárov skleníkových plynov, resp. od socio-ekonomického vývoja ľudstva vo všeobecnosti.
Projected changes of warm season (May-September) rainfall events in an ensemble of 30 regional climate model (RCM) simulations are assessed for the Czech Republic. Individual rainfall events are identified using the concept of minimum inter-event time and only heavy events are considered. The changes of rainfall event characteristics are evaluated between the control (1981-2000) and two scenario (2020-2049 and 2070-2099) periods. Despite a consistent decrease in the number of heavy rainfall events, there is a large uncertainty in projected changes in seasonal precipitation total due to heavy events. Most considered characteristics (rainfall event depth, mean rainfall rate, maximum 60-min rainfall intensity and indicators of rainfall event erosivity) are projected to increase and larger increases appear for more extreme values. Only rainfall event duration slightly decreases in the more distant scenario period according to the RCM simulations. As a consequence, the number of less extreme heavy rainfall events as well as the number of long events decreases in majority of the RCM simulations. Changes in most event characteristics (and especially in characteristics related to the rainfall intensity) depend on changes in radiative forcing and temperature for the future periods. Only changes in the number of events and seasonal total due to heavy events depend significantly on altitude.
The paper presents the results of analysis of temporal and spatial changes of snow water equivalent (SWE) in the mountain basin of the upper Hron River over 40 hydrological years. Spatial distribution of SWE was simulated with the WaSiM model. Measured as well as simulated data indicated despite large temporal variations of SWE, the period since the mid-1980-ties seems to have less snow than the previous decades. Simulations indicated pronounced decrease of SWE in the southern part of the basin. Changes of SWE in the highest mountains were not so pronounced. The analysis of previous decades is considered to be the first step in the assessment of impacts of expected climate changes in the future. and Príspevok je venovaný analýze časových a priestorových zmien vodnej hodnoty snehovej pokrývky v povodí horného Hrona za obdobie 40 rokov (hydrologické roky 1962-2001). Priestorové rozdelenie vodnej hodnoty snehu bolo simulované modelom WaSiM. Napriek veľkej variabilite vodnej hodnoty merané aj simulované údaje ukazujú, že od polovice 80-tych rokov 20. storočia došlo v povodí k poklesu vodnej hodnoty snehu. Výsledky simulácie priestorového rozdelenia vodnej hodnoty poukazujú na výrazný pokles najmä v južnej časti povodia. Zmeny vodnej hodnoty v najvyšších častiach povodia v jeho severnej oblasti neboli také dramatické. Analýza časových a najmä priestorových zmien vodnej hodnoty snehu za posledné dekády je prvým krokom pri odhade dopadu možnej zmeny klímy na budúce zmeny snehovej pokrývky.
In the context of discussed global climate change the emphasis is placed mainly on the adaptability of the water management methodology at present time. Therefore a questionnaire inquiry oriented to the perception of the climate change impact and current state of adaptation strategies implementation was carried out and evaluated. The research was realised among the water management experts in six large transboundary basins: Elbe, Rhine, Guadiana, Amudaria, Orange and Nile. The questionnaire was divided into six parts concerning for example: expected climate change impacts, adaptation measures, drivers for development of adaptation strategy, adaptation barriers etc. Responses were evaluated with rating and the dominant answers and lists of priority were established. Results were evaluated looking for overall conclusions in all or almost all regions, as well as conclusions for each region. The main benefit of the research lies in the evaluation based principally on the opinions of policy makers, stakeholders and water managers in the river basins not on the climate scenarios. The outcomes have proved understanding of the climate change impact issue over all six basins, only the approach to adaptation is partly different. The historical development of water management in the basin influences the perception as well. and V současnosti se v souvislosti s diskutovanou globální změnou klimatu stále zvyšuje důraz na požadavek adaptability metodik uplatňovaných ve vodním hospodářství. Z tohoto důvodu byl v šesti vybraných světových povodích uskutečněn a vyhodnocen dotazníkový průzkum mezi oslovenými experty se zaměřením na chápání důsledků klimatické změny a na zjištění aktuálního stavu implementace adaptačních opatření v povodí. Šlo o povodí Labe, Rýna, Guadiany, Amudarji, Orange a Nilu. Dotazník byl rozdělen do několika sekcí týkající se např. očekávaných dopadů klimatické změny, adaptačních opatření, podnětů pro návrh strategie adaptace, bariér adaptace atd. Dotazníky byly vyhodnocovány pomocí bodování a stanoveny vždy dominantní odpovědi a seznamy priorit. Výsledky byly vyhodnoceny vždy z obecného hlediska i v rámci konkrétního povodí a vzájemně porovnány. Významným přínosem bylo, že průzkum byl založen na závěrech a zkušenostech expertů, nikoli na klimatických scénářích. Ukázalo se, že ve všech povodích bylo dosaženo pochopení problému dopadu klimatické změny, jen přístup k vlastní adaptaci je částečně odlišný. Záleží rovněž na historickém vývoji vodního hospodářství v daném regionu
The paper reviews recent climate change impact studies for the Slovak National Climate Program (SNKP). Basic adaptation strategies are also discussed. Priorities for future research within the SNKP are suggested. and Článok prináša prehľad o metodických postupoch, používaných v súčasnosti na určovanie možného vplyvu zmeny klímy na odtokové procesy. Nadväzuje pritom na prehľad uvedený v prácach S z o l g a y, et al. (1997), S z o l g a y a H l a v č o v á (2000), H l a v č o v á, et al. (2000) a sústreďuje sa najmä na pokrok v uvedenej problematike za posledné 4 roky, dokumentovaný na základe publikácií v niektorých vedúcich karentovaných časopisoch a výsledkov správy IPCC. Identifikuje smery výskumu v oblasti analýzy časových radov pre posudzovanie možnej zmeny podmienok tvorby odtoku, ako aj v oblasti využívania závislostí medzi odtokom a jeho podmieňujúcimi činiteľmi na určovanie možnej zmeny odtoku v dôsledku klimatickej zmeny.