Vpliv obiskov na mikroklimo jam – analitični pristop

The theoretical basis for describing natural steady-state conditions in caves as well as for their changes in time that follow from the simple advection-diffusion equation, is given. The impacts of visits to caves – direct impacts due to anthropogenic emissions of heat and CO2, as well as indirect ones, such as illumination and possible drafts when opening the door to the cave – are estimated in dependence to the number of visitors and the size of the cave: the size with which the effects of the visits are below the detection threshold is estimated. It is shown that the sources cause linear responses, while the consequences of the exchange with the walls of the cave or with the exterior depend on time exponentially. Characteristic times for linear as well as for exponential responses are roughly estimated.Podane so teoretične podlage za opis naravnih ravnotežnih pogojev v jamah in za njihove časovne spremembe, kot izhajajo iz preproste advektivno-difuzijske enačbe. Ocenjeni so vplivi obiskov v jame - tako neposredno zaradi antropogenih emisij toplote in CO2, kot posrednih, kot so razsvetljevanje in možni prepihi pri odpiranju vrat v jamo. Velikost teh vplivov je ocenjena glede na število obiskovalcev in glede na velikost jame: ocenjena je velikost, pri kateri so učinki obiskov pod pragom zaznavanja. Pokazano je, da viri povzročajo linearne odzive, medtem ko so posledice izmenjav s stenami jame ali z zunanjostjo eksponentno odvisne od časa. Grobo so ocenjeni karakteristični časi za linearno kot za eksponentne odzive so grobo ocenjeni

Utjecaj emisija termoelektrane Šoštanj na onečišćenje Srednje Europe sumpornim dioksidom tijekom zime

The simulation of the wintertime transport of sulphur dioxide based on emissions made in three winter months from December 1999 to February 2000 by the thermo electric power plant located in Šoštanj (TEŠ) in Slovenia is presented. Our study is focused on estimation the regional distribution of SO2 from this source – the range and level of its impact on Central Europe. The dispersion model MEDIA (Piedelievre et al., 1990), coupled with the meteorological fields of Aladin/LACE (Janoušek 1999), and the operational model for weather forecasting over Central Europe were used. The simulation was run on all winter days of the simulation period. The daily results were accumulated and averaged into monthly and seasonal estimates of air pollution caused by emissions from the TEŠ. As expected, their biggest effects are seen in the nearest regions. Despite the relatively high emission levels, high concentrations with damaging effects are mainly limited to regions approximately 50 km from the source. Slightly increased pollution levels, distinguishable from the background threshold, also spread across other parts of Slovenia, southern parts of Austria, northern parts of Croatia, western Hungary and north-eastern Italy. The TEŠ’s contribution to air pollution in selected neighbouring cities is estimated. On a regional scale, the results of deposition are compared with an LADM evaluation (Berge and Jakobsen, 1998).Prikazana je simulacija transporta sumpornog dioksida, koji je tijekom tri zimska mjeseca od prosinca 1999. do veljače 2000. emitiran iz termoelektrane Šoštanj (TEŠ) u Sloveniji. Naša studija je fokusirana na procjenu regionalne razdiobe SO2, koji potječe iz TEŠ, odnosno na razinu i raspon utjecaja TEŠ na Srednju Europu. Primijenjeni su model disperzije MEDIA (Piedelievre i sur., 1990), koji je združen meteorološkim poljima Aladin/LACE modela (Janoušek 1999), te operativni prognostički model za Srednju Europu. Simulirani su svi dani u promatranom zimskom razdoblju. Na temelju dnevnih modeliranih vrijednosti procijenjene su srednje mjesečne i sezonske vrijednosti onečišćenja uzrokovanog emisijama TEŠ. Kao što se i očekivalo, utjecaj termoelektrane je najveći u područjima najbližim izvoru. Unatoč relativno velikim razinama emisije, visoke koncentracije sa štetnim efektima uglavnom se nalaze na udaljenostima od izvora do 50 km. Blago povišene razine onečišćenja, koje je moguće razlikovati od temeljnog onečišćenja, također se nalaze u drugim dijelovima Slovenije, dijelovima južne Austrije, sjeverne Hrvatske, zapadne Madđarske i sjeveroistočne Italije. Procijenjen je i doprinos TEŠ-a onečišćenju zraka u odabranim susjednim gradovima. Procijenjena taloženja uspoređena su na regionalnoj skali s procjenama LADM modela (Berge i Jakobsen, 1998)

Vpliv obiskov na mikroklimo jam, rezultati meritev v Škocjanskih jamah

Tourism activities in caves can result in changes in the microclimates of caves. The natural microclimate in closed caves is constant due to the balance between cave air and cave walls, while in open caves exchanges with outside air influence the microclimate. Visits to caves, especially in closed smaller caves, can thus endanger the natural balance if the microclimate does not return to natural conditions quickly enough.Continuous monitoring of the temperature and concentration of carbon dioxide in Škocjan Caves enables the assessment of the impact of visits. For this purpose, we used data measured in the relatively closed Silent Cave, at the locations named Calvary (Kalvarija), Tent (Šotor), and Passage (Prehod) in 2016, and in the wide open Murmuring Cave, at the locations named Bridge (Most) and Rimstone Pools (Ponvice), in 2013. The outdoor air temperature, as measured at the Škocjan meteorological station on the surface plateau, was considered in both cases. Along the tourist part of Škocjan Caves, the most closed part of the cave in Silent Cave is the location at Calvary, when the entrance doors through an artificially dug tunnel are closed. During the visits, the microclimate is subjected to draughts through open doors and to anthropogenic emissions. The data suggest that the influence of draughts predominates over direct anthropogenic emissions. In winter or on cold days air flows upwards and through the tunnel out of the cave, whereas in summer or on warm days it flows downwards. In such cases, the CO2 concentration decreases markedly due to the downwards chimney effect as the concentration in the outside air is much lower than in the cave. The data show that the temperature overnight and towards morning always returns to its natural value even in this rather small location in the cave. The changes in CO2 concentration persist for a longer period, until the time of the first visit the next morning, when it is again perturbed by a new visit. The data on time courses support the theoretically estimated characteristic of the exponential decline of disturbances backward towards natural conditions, depending on the size of a cave and on the efficiency of exchanges with its walls. For tem­perature, this characteristic time tT is about three to six hours at the Calvary site. The return of CO2 to natural conditions tCO2 is longer and its estimate less reliable than the one for temperature. In the wide-open and large Murmuring Cave, the impact of visits is negligible throughout the year. In this part of the cave we can observe the influence of external daily and annual changes, the amplitudes of which get smaller, and their phase lags bigger, deeper in the cave.Turistična dejavnost v jamah lahko spreminja naravno jamsko mikroklimo, ki je v zaprtih jamah nespremenljiva ob ravnovesju med jamskim zrakom in jamskimi stenami. V odprtih jamah so možne izmenjave z zunanjim zrakom. Obiski jam lahko predvsem v zaprtih manjših jamah ogrozijo to ravnovesje, če se mikroklima ne vrne dovolj hitro v naravne razmere. Stalni monitoring temperature in koncentracije ogljikovega dioksida v Škocjanskih jamah omogoča oceno posledic obiskov. Za lokacije v Tihi jami (Kalvarija, Šotor, Prehod) so bili uporabljeni podatki iz leta 2016, za morebitne vplive v Šumeči jami (Most in Ponvice) pa podatki iz leta 2013. V obeh primerih so bili upoštevani tudi podatki za zunanji zrak z meteorološke postaje Škocjan na površju. V turističnem delu Škocjanskih jam je najbolj zaprt del jame lokacija v Tihi jami na Kalvariji, ko so vrata skozi umetno izkopan predor zaprta. Med obiski pa je mikroklima izpostavljena prepihu skozi odprta vrata in antropogenim emisijam. Podatki kažejo, da vpliv prepiha prevladuje nad vplivom neposrednih antropogenih emisij. Pozimi ali v hladnih dneh teče zrak navzgor in skozi predor iz jame, poleti ali v toplih dneh pa teče navzdol. V takih primerih se koncentracija CO2 izrazito zmanjša zaradi navzdolnjega učinka dimnika, saj je koncentracija v zunanjem zraku veliko nižja kot v jami. Podatki kažejo, da se temperatura čez noč in proti jutru vedno vrne na naravno vrednost tudi na tem precej majhnem prostoru v jami. Spremembe koncentracije CO2 trajajo dlje časa – do prvega obiska naslednje jutro, ko ob novem obisku nastane nova motnja. Podatki o časovnih potekih podpirajo teoretično predpostavko o eksponentnem upadu vpliva motenj nazaj proti naravnim razmeram, odvisno od velikosti jame in učinkovitosti izmenjav toplote, CO2, itd. z njenimi stenami. Za temperaturo je na Kalvariji ta značilni čas eksponentnega upada motenj približno od tri do šest ur. Vrnitev CO2 proti naravnim razmeram pa poteka dlje in ocena je manj zanesljiva od tiste za temperaturo. V dokaj odprti in veliki Šumeči jami je vpliv obiska zanemarljiv skozi vse leto. V tem delu jame lahko opazujemo vpliv zunanjih dnevnih in letnih sprememb, katerih amplitude so čedalje globlje v jami vse manjše, njihov fazni zaostanek pa je vse večji

Prethodno priopćenje o spektralnim karakteristikama bure na otoku Rabu

In contrast to the known models of bora wind, originating from the idea of rather uniform hydraulic flow, the basis of this physical model explanation are observed gust characteristics of bora. The essence of this model explanation is the fact, that bora is primary a very gusty wind, and the idea that main gusts are not a consequence of turbulence in a general flow, but of cylinders of cold air rolling down the slope on the warm side of the ridge. Main rolls together with the turbulence and partly sliding of cold air develop a general flow with observed bora characteristics

Utjecaj advekcije i rada sila na mahovitost bure

Local wind changes within the flow of the Adriatic Bora are investigated in the case of 8 December 2001 that was simulated with the WRF/ARW model in a 333 m horizontal resolution and with all relevant model variables archived during a 3 h time interval with 1 s temporal resolution. Along a selected cross section, two locations of strong gusts in the lee of a Dinaric mountain ridge are found - the upper one on the slope and the other over the sea close to the coastline; in between the wind is considerably weaker. About 16 to 18 gusts developed in the 3 h interval at both locations with an average period of approximately 8.5 min. The advective transport of kinetic energy (KE), the work of the unbalanced part of the pressure gradient force and the diffusion and dissipation of KE cause the local change ΔKE, and their quasi-periodic fluctuations lead to gusts and lulls. The results of the numerical simulation enable an estimation of the contributions of advection, the work of forces and of turbulence and dissipation effects. Advective contributions to local changes are more or less in the phase with ΔKE and ahead of the phase of KE, while the contributions of work are generally smaller and in the opposite phase: so in general the advection and the work effects oppose each other. The advection and the work effects are not spatially homogeneous, i.e. they cease and even change their sign between the two locations of the strongest gusts and so there is no continuous displacement of KE from the upper to the lower location by either of the two effects: their contributions interchange with each other down the slope.Lokalne promjene vjetra u buri istražene su u slučaju od 8. prosinca 2001. koji je bio simuliran WRF/ARF modelom s horizontalnom rezolucijom od 333 m i sa svim relevantnim modelskim varijablama arhiviranim tijekom 3-satnog vremenskog intervala s vremenskom rezolucijom od 1 s. Duž odabranog presjeka paralelnog s burom nađene su dvije lokacije u navjetrini Dinarida s jakim udarima – jedna na obronku planine i druga iznad mora blizu obale, dok je između njih vjetar znatno slabiji. U promatranom trosatnom intervalu razvilo se oko 16 do 18 udara vjetra s prosječnim periodom od približno 8,5 minuta. Advektivni transport kinetičke energije (KE), rad neuravnoteženog dijela sile gradijenta tlaka te difuzija i disipacija KE uzrokuju lokalnu promjenu ΔKE, i njihove kvazi-periodičke fluktuacije vode do pojave udara i zatišja. Rezultati numeričke simu- lacije omogućavaju procjenu doprinosa advekcije, rada sila te učinaka turbulencije i di- sipacije. Advekcijski doprinosi lokalnim promjenama su više ili manje u fazi s ΔKE i ispred faze KE, a doprinosi rada su općenito manji i u suprotnoj fazi. To znači da advekcija i rad općenito djeluju suprotno. Učinci advekcije i rada nisu prostorno homogeni, tj. oni prestaju ili čak mijenjaju predznak između dvije lokacije najjačih udara. Stoga nema kontinuiranog pomaka KE od više prema nižoj lokaciji koji bi bio uzrokovan bilo kojim od ova dva učinka: njihovi se doprinosi međusobno izmjenjuju niz obronak

PRECIPITATION AT THE SOUTH SIDE OF THE ALPS AND WEATHER TYPES

Statistical investigation is performed to find connections between the two "vectors": one describing weather type (like shape of the geopotential field, wind direction and velocity, stability, moisture, etc.) and the other describing precipitation (for example location of precipitation spot, its area and shape, the accumulated precipitation amount, etc.). The most precipitation-relevant descriptor variables in regions south of the Alps are found to be geopotential height, relative humidity, wind direction and vorticity

SPATIAL INTERPOLATION OF HOURLY GAUGE AND RADAR PRECIPITATION DURING MAP SOP

During MAP SOP (fall 1999) a network of additional automatic rain gauges was installed in the mountains of western Slovenia. The meteorological radar in Fossalon (OSMER, FVG) was operational as well. Raingauges are considered to provide measurements with good point accuracy, but offer little information on the spatial variability of precipitation. On the other hand the radar measurements give very good image of spatial distribution of precipitation, but the absolute quantity of precipitation is unreliable due to several systematic errors, especially occultation in mountainous areas. Different geostatistical approaches are tested to improve spatial distribution of precipitation, using raingauge and radar measurements. The spatial distribution of precipitation shows that the location of precipitation maxima is well correlated to the topographic features of the area and that the operational automatic gauge network is not dense enough to detect the spatial variability of precipitation in a scale of individual watersheds. The use of additional MAP data proved to be of great use, for example for such event as the one of heavy rainfall and debris flow in Loška Koritnica Valley in 2000

DOWNSCALING OF ERA40 FOR THE WIND FIELD IN A COMPLEX TERRAIN

This study deals with the optima] strategy for setting up the ALADIN model for the purpose of dynamic downscaling of ERA40 over the Alpine region. The mesoscale model wind field is compared with MAP-SOP reanalysis data and with wind observations at eleven Slovenian stations. As expected, there is an improvement in the conventional statistics at a 10-km grid as compared to the 40-km analyses. However, the differences between the mesoscale model scores at various domains can be greater than the difference between the MAP-SOP reanalyses and a particular mesoscale simulation

HIGH-RESOLUTION WIND CLIMATOLOGY FOR SLOVENIA: A SPATIO-TEMPORAL VERIFICATION

An NWP model AI.AD1N is applied for dynamical downscaling of ERA40. The purpose is to deduce the wind climatology of Slovenia at horizontal scales around ten kilometers and finer. Verification against MAP-SOP reanalyses indicates that the downscaling has been successful. However, MAP-SOP reanalysis data produce wind roses closer to the observations and contain more energy in the subdiurnal range. On the other hand, a 10-km ALADIN overestimates the amount of energy in longer than diurnal periods