NENAD BUZJAK - MIKROKLIMA KAO KOMPONENTA GEOEKOLOŠKOG VRJEDNOVANJA SPILJA – PRIMJER SPILJE U BELEJSKOJ KOMUNADI (BELEJ, OTOK CRES)

7/30/2019 NENAD BUZJAK - MIKROKLIMA KAO KOMPONENTA GEOEKOLOKOG VRJEDNOVANJA SPILJA PRIMJER SPILJE U BELEJSK

1/14

97

MIKROKLIMA KAO KOMPONENTA GEOEKOLOKOGVRJEDNOVANJA SPILJA PRIMJER SPILJE U BELEJSKOJ

KOMUNADI (BELEJ, OTOK CRES)

MICROCLIMATE AS A COMPONENT OF THE GEOECOLOGICALEVALUATION OF CAVES EXAMPLE OF THE CAVE IN BELEJSKA

KOMUNADA (BELEJ, ISLAND OF CRES)

NENAD BUZJAK

Speleoloki klub "Samobor" /Caving Club Samobor

UDK 551.44(497.5 Belej

Primljeno /Received: 2007-09-08 Izvorni znanstveni lanakOriginal scientific paper

Mikroklimatsko istraivanje Spilje u Belejskoj komunadi obavljeno je u terminu od 1. veljae do 19.kolovoza 2007. U analizi su koriteni podaci mjerenja temperature i vlanosti zraka zabiljeni elektronikimtermohigrografima. Mjerne toke postavljene su u blizini ulaza i u kanalu pri dnu spilje. Istraivanje je obavljenokao komponenta geoekolokog vrednovanja spilje za potrebe planiranja turistikog koritenja. Mjerenjeje obavljeno u toplom dijelu godine jer bi u to vrijeme spilju posjeivalo najvie turista pa je to razdobljenajinteresantnije budui da posjetitelji utjeu na izmjene mikroklimatskih parametara.

Kljune rijei: spilja, mikroklima, geoekoloko vrednovanje, termohigrograf, Belej, otok Cres

Microclimate research of the Cave in Belejska komunada was conducted in the period from 1 Februaryto 19 August 2007. In the analysis of temperature and air humidity measurement data recorded by electronic

thermohygrograph were used. Measurement points were installed in the vicinity of the entrance and at thebottom of the cave. The research was carried out as a component of the geoecological evaluation of the cave forthe purpose of planning its tourist use. The measurement was conducted during the warm part of the year whenthe majority of tourists would visit, therefore the period was particularly interesting since the cave visitors havean impact on changes in microclimatic parameters.

Key words: cave microclimate, geoecological evaluation, thermohygrograph, Belej, Island of Cres

Uvod

Otok Cres obiluje povrinskim i podzemnim

krkim fenomenima (Buzjak, 1997). Meupodzemnima prevladavaju manje spilje i jameoblikovane preteito u krednim karbonatnimnaslagama (Buzjak i dr., 1997).

Spilja u Belejskoj komunadi smjetena je kodsela Belej u sredinjem dijelu otoka Cresa (Sl. 1.).Od crkve u Beleju udaljena je 1,9 km u smjeru 195.Ulaz je na nadmorskoj visini 164 m. Prema OGK,list Cres (Maga i dr., 1968) spilja je oblikovanau naslagama uslojenih vapnenaca donjokrednestarosti. To je morfoloki jednostavna spilja.

Sastoji se od dva kanala koji su, s obzirom na

Introduction

The Island of Cres abounds with surface andunderground karst phenomena (Buzjak 1997).Among the underground karst phenomena, smallercaves and pits formed in predominantly Cretaceouscarbonate beds prevail (Buzjak et al., 1997).

The Cave in Belejska komunada (Spilja uBelejskoj komunadi) is located near the village ofBelej, in the central part of the Island of Cres (Fig.1), at a distance of 1.9 km from the Belej church,bearing 195. The entrance is at an elevation of 164m. According to a geological map (Maga et al.,1968) the cave was formed in Lower Cretaceous

limestone beds. The cave is of simple morphology.


2/14

98

N. Buzjak Geoadria 12/2 (2007) 97-110

ouvane mikroreljefne oblike u bokovima i stropukanala, oblikovani u glavnoj etapi speleogenezedjelovanjem podzemnog toka. Voda je u spilji danasprisutna samo u obliku prokapnice koja je obilnau kinim razdobljima. U ulaznom kanalu i pri dnu

taloene su ili se jo uvijek taloe debele naslagesige. U dijelovima kanala obilno je nataloenokrje te sitnozrnati sediment koje je nanio vodenitok ili je transportiran prokapnicom s povrine.Tlocrtna duljina spilje je 60 m, a dubina 12 m 1.Uruavanje kao speleogenetski proces najizraenijeje u ulaznom dijelu. Ulaz je u dnu uruene ponikvenastale uruavanjem dijela stropa iznad spiljskeupljine, to je vidljivo po niama u bokovimaponikve. Okrenut je prema sjeveru, ali ga dubinaulazne ponikve titi od direktnog utjecaja vjetrasjevernog smjera. Sa sjeveroistone i istone strane

padina ponikve je poloena, ali je utjecaj buresmanjen jer je povrina obrasla gustom umom.

Spilja je poznata lokalnom stanovnitvu oddavnina o emu svjedoe arheoloki nalazi kojitek oekuju strunu obradu. U usmenoj predajio koritenju spilje u novijoj povijesti poznatje podatak da je tijekom talijanske okupacijeotoka u spilji bila ilegalna pecara rakije. Spilju su

1 Budui da u arhivi SO HPD "eljezniar" (Zagreb) o spiljinema zapisa navedene dimenzije su dobivene mjerenjem naskeniranom i georeferenciranom nacrtu A. Novosela i O.

Vukadinovia (softver Map Maker Gratis 3.5).

It consists of two passages that were formed, basedon preserved microrelief forms in the sidewalls andceiling, during the main phase of speleogenesis byunderground stream. Water is nowadays presentonly as drip water, abundant during the rainy

seasons. In the entrance passage and along itsbottom, thick speleothem deposits already exist orare still in the process of formation. Parts of thepassage contain abundantly deposited rock debrisand fine-grained sediment flushed in by water flowor transported by drip water from the surface. Thecave length is 60 m and its depth is 12 m1. Collapseas a speleogenetic process is most prominent inthe entrance zone. The entrance is at the bottomof a collapsed doline created after a portion of theceiling above the cavern had collapsed, the evidenceof which are niches in the sidewalls of the doline.The entrance faces north, but the depth of the

entrance doline protects it from the direct impact ofthe northern wind. From NE and E sides the slopeof the doline is of slight inclination but the impactof the north-easterly wind (bora) is reduced due tothe surface being covered with dense forest.

The cave has been known to the local inhabitantsfrom times immemorial and archaeologicalfindings, pending expert elaboration, testify to this

1 Given the archives of SO HPD "eljezniar" (Zagreb)contain no record of the cave, the cited size has been obtainedby means of measuring the scanned and georeferencedsketch by A. Novosel and O. Vukadinovi (software Map

Maker Gratis 3.5).

Slika 1. Geografski smjetaj Spilje u Belejskoj komunadiFigure 1 Geographic position of the Cave in Belejska komunada


3/14

99


speleoloki istraili lanovi SOPD "eljezniar"(Zagreb) poetkom 90-ih godina 20. stoljea2. U tosu vrijeme, voeni Brankom Rebroviem iz Beleja,Cres istraivali i lanovi DISKF-a (Zagreb) te sutom prilikom posjetili i ovu spilju (Z. Greguri i J.

Zmai usmeno).Tijekom 2005. i 2006. spilju su na poziv g.

Jordana Kuia iz Beleja, zainteresiranog za njenoturistiko koritenje, istraivali lanovi SOPD"eljezniar" (Zagreb) B. Jali, V. Jali i D.Lovreti. Oni su crtali novi nacrt koji postoji samou radnoj verziji (V. Jali usmeno).

Dosadanja speleometeoroloka mjerenja naCresu

Koliko je prema dostupnim podacimapoznato, do novijeg vremena na podruju Cresanisu obavljana dugotrajna mikroklimatolokaistraivanja unutar speleolokih pojava. Sredinom90-ih godina takva su istraivanja, u okviruprojekta istraivanja bilja na ulaznim dijelovimaspilja i jama, obavljali S. i N. Buzjak i to u jamiBanievoj peini (ampari), jami Gaparet i Jamina Sredi ( Fiedler, Buzjak, 1998; Buzjak, 2001).

Metoda istraivanja

Mjerenje u Spilji u Belejskoj komunadi obavljenoje u terminu od 1. veljae do 19. kolovoza 2007.Koritena su dva termohigrografa tipa HoboRH/Temp (Onset Computer Corporation, SAD) smogunou biljeenja niza podataka (data logger-i). Vrijednosti temperature mjerene su u visokojrezoluciji na dvije decimale. Programirani intervalmjerenja je bio 1 sat. U analizi su koriteni podaci4799 mjerenja koje su instrumenti zabiljeili umjernom razdoblju. Instrumenti su na mjernetoke postavljeni 29. sijenja 2007., ali ti podaci

nisu uzeti u obzir zbog greaka koje se javljaju umjerenjima zbog prilagoavanja senzora na uvjeteokoline. Za provjeru strujanja zraka koriten jeanemometar TurboMeter (Davis Instruments,SAD). Prilikom postavljanja termohigrografa namjerne toke strujanje zraka nije zabiljeeno, tone znai da se ne javlja u odreenim prilikama.

fact. Through word of mouth on the usage of thecave in recent history, an illegal brandy distillerywas known to be located inside the cave duringItalian occupation of the island. The cave wasspeleologically explored by cavers of caving club

SOPD "eljezniar" (Zagreb) in the beginning of1990s2. At the time, led by Branko Rebrovi fromBelej, Cres was also being explored by members ofcaving club DISKF (Zagreb) who, on that occasion,visited this cave as well (Z. Greguri and J. Zmai,personal communication).

During 2005 and 2006 the cave was researchedby the members of SOPD "eljezniar" (Zagreb)B. Jali, V. Jali and D. Lovreti, at the invitationof Mr Jordan Kui from Belej, who was interestedin it as a tourist attraction. They drew a new draftof the cave (V. Jali, personal communication).

Cave microclimate researches on Cres to date

According to accessible data, to date nolong term microclimatological research withinspeleological features has been conducted inthe Cres area. In mid 90s a similar research wasconducted within the framework of the Cave andPit near Entrance Flora Study by S. and N. Buzjakin Banieva spilja Cave (ampari), Gaparet jamaPit and Jama na Sredi Cave (Fiedler, Buzjak,1998; Buzjak, 2001).

Research method

Measurement in the Cave in Belejska komunadawas conducted from 1 February to 19 August 2007.Two thermohygrographs Hobo RH/Temp type(Onset Computer Corporation, USA) data loggerswere used. Temperature values were measured inhigh resolution. The programmed measurementinterval was 1 hour. Data analysis from 4799measurements, recorded by instruments in themeasurement period, was used. The equipment wasinstalled at measurement points on January 29, butthe derived data were not taken into considerationdue to errors occurring in measurements as a resultof sensor adjustment to environment conditions.Assessment of cave airflow was done by meansof TurboMeter anemometer (Davis Instruments,USA). Upon installation of the thermohygrographs

2 Toan datum topografskog snimanja spilje nije poznat jeru arhivi SO HPD "eljezniar" (krae SO) nema zapisa(arhivar M. Uroi, usmeno). Istraivanje je vjerojatnoobavljeno 1990.-1992. godine kada su speleolozi SO-a

istraivali otok Cres.

2 The exact date of the cave topographic survey is unknowngiven the SO HPD "eljezniar" (shorter SO) archives donot contain any record of it (archivist M. Uroi, personalcommunication). The exploration was probably conductedfrom1990 to 1992 when the SO cavers explored the island

of Cres.


4/14

100


Mjerenje je obavljeno na dvije mjerne toke(Sl. 2.):

MT1 - na dnu kamenog mosta u dvorani 25,5 mod ulaza i 1,9 m iznad dna,

MT2 - u lijevom boku na dnu kanala 6,5 m odulaza.

Obje lokacije mjernih toaka u vrijemepostavljanja i micanja termohigrografa bile su suheuz malu koliinu vode prokapnice i cijednice.Na ulazu su, kao zatita od nekontroliranogulaenja, postavljene vodoravne metalne ipkekoje nimalo ne sprjeavaju prirodnu cirkulacijuzraka izmeu povrine i spilje.

Rezultati mjerenja obraeni su osnovnimstatistikim metodama (srednja vrijednost,

standardna devijacija i koeficijent varijabilnosti).

at measurement points, no airflow was detected,which does not mean that it does not occasionallyoccur.

The measurement was conducted at twomeasurement points (Fig. 2):

MT1 at the bottom of the stone bridge in thechamber 25.5 m from the entrance and 1.9 mabove the chamber bottom,

MT2 in the left sidewall at the bottom of thepassage 6.5 m from the entrance.

Both locations of measurement points at thetime of the thermohygrographs installation andmovement were dry with a minimum amount ofdrip water. At the entrance, as a protection fromunmonitored entering, horizontal metal bars thatdo not in the least obstruct natural ventilation

between the surface and the cave were fixed.

Slika 2. Nacrt Spilje u Belejskoj komunadi s lokacijama termohigrografa (MT1 i MT2)Figure 2 The plan of the Cave in Belejska komunada with the thermohygrographs' locations (MT1 and MT2)


5/14

101


Rezultati i rasprava

Temperatura zraka

Maksimalna izmjerena temperatura zraka naMT1 je bila 13,41 C, a minimalna 10,97 C. NaMT2 maksimalna zabiljeena temperatura zraka jebila 16,04 C, a minimalna 8,13 C.

Hod srednje dnevne temperature zraka prikazanje na slici 3. Primjetna je znatna oscilacija srednjihdnevnih temperatura MT2 do kraja oujkanakon ega se smanjuje uz openiti trend porastatemperature. Oscilacije su rezultat pritjecanja zrakarazliitih temperatura i vlanosti s povrine u spilju.Vei padovi vjerojatno su posljedica utjecaja bure.Utjecaj vjetra na spiljske temperature zraka vidljivje iz usporedbe podataka sa srednjim dnevnim

temperaturama i srednjom dnevnom brzinomvjetra klimatoloke postaje Cres. Iako je ta postajaudaljena od Beleja, a i reljefni uvjeti koji utjeu naznaajke prizemne cirkulacije zraka su drugaijinego u Beleju, korelacija postoji (Sl. 4.). 11. i12. veljae 2007. dolazi do porasta brzine vjetra.Prevladavajui vjetar je bura jaine 4. Dolazi do padatemperature zraka u Cresu, a pritjecanje hladnogzraka izaziva pad temperature na MT2. Smanjenjebrzine vjetra promjenljivih smjerova (s prevlauonih iz junog kvadranta) izmeu 12. i 15. veljae2007. je praeno laganim rastom temperature. Od

15. veljae 2007. prevladavaju vjetrovi sjevernoga

The measurement results were processed usingbasic statistical methods (mean value, standarddeviation and variability coefficient).

Results and discussion

Air temperature

The maximum air temperature measuredat MT1 was 13.41 C, and the minimum was10.97 C. At MT2, the maximum recorded airtemperature was 16.04 C and minimum 8.13 C.

An average diurnal air temperature trend isshown in figure 3. A considerable oscillation ofmean diurnal temperatures at MT2 was observeduntil the end of March after which it began todecrease with the increase of temperature trend.Oscillations are a result of the inflow of variousranges of air temperature and humidity fromthe surface into the cave. The significant dropsare likely to be caused by bora. The impact ofwind on cave air temperature is evident from thecomparison of mean diurnal temperature datawith that of mean diurnal wind velocity, measuredat the climatological station on Cres. Even thoughthe station was far from Belej and relief conditionsimpacting ground air circulation features differedfrom those in Belej, the correlation existed (Fig. 4).On 11 and 12 February 2007 the wind velocity

began to rise. The prevailing wind was a force 4

Slika 3. Hod srednjih dnevnih temperatura na MT1 i MT2Figure 3 Mean diurnal temperature trend at MT1 and MT2


6/14

102


Slika 4. Usporedba dnevnog hoda srednje brzine vjetra te srednje dnevne temperature klimatoloke postaje Cres iMT2 (11.-20. veljae 2007.)Izvor: DHMZ, ZagrebFigure 4 Comparison of diurnal trend of mean wind velocity with mean diurnal temperature at climatologicalstation Cres and MT2 (11-20 February 2007)Source: Meteorological and Hydrological Service, Zagreb

Slika 5. Usporedba hoda srednjih mjesenih temperatura zraka u Spilji u Belejskoj komunadi (MT1 i MT2) sahodom srednjih mjesenih temperatura u Cresu za razdoblje 1991.-2000. i 2007. godineIzvor: DHMZ, ZagrebFigure 5 The comparison of mean monthly air temperature trends in the Cave in Belejska komunada (MT1 andMT2) with mean monthly temperature movements/trends in Cres for period 1991-2000 and 2007Source: Meteorological and Hydrological Service, Zagreb


7/14

103


smjera ija brzina jaa i traje do 17. veljae to jepraeno vidljivim padom temperature na povrinii u podzemlju. Iza tog razdoblja brzina vjetraslabi, prevladavajui smjer je juni (S, SE i SSE), atemperatura je u laganom porastu. Slian je utjecaj

bure na temperaturu spiljskog zraka zabiljeen uurovia spilji u ilipima (Buzjak, 2006b, 2006c).Na MT1 oscilacije postoje, ali su zamjetno manjejer je toka dalje od ulaza i pod manjim utjecajemvanjskih uvjeta.

Srednje mjesene temperature zraka pravilnorastu od veljae prema kolovozu (Tab. 1; Sl. 5.),te porast na povrini slijedi porast u spilji (Sl.6.). Odstupanja od srednjih vrijednosti vea suna MT2 to je vidljivo iz amplitude, standardnedevijacije (s) i koeficijenta varijabilnosti (V).Uzrok je blizina ulaza i jai utjecaj s povrine

jer je ulaz prostran i nije zatvoren vratima negovodoravno poloenim metalnim ipkama meukojima vanjski zrak neometano ulazi u spilju(kao to i spiljski zrak neometano izlazi van). Topotvruje i prosjena temperatura zraka na MT2koja je via nego dublje u unutranjosti spilje toje posljedica pritjecanja toplog zraka s povrineu toplom dijelu godine. S obzirom na rezultatespomenutih mjerenja na Cresu (Fiedler, Buzjak,1998) te mjerenja u drugim speleolokim pojavamaHrvatske (arhiva istraivanja autora) opravdanoje pretpostaviti da je temperatura zraka hladnijih

razdoblja godine u ulaznom dijelu spilje (MT2)nia u odnosu na unutranjost dalje od ulaza.

Iz podataka (Tab. 1) je vidljivo da i na MT1postoje utjecaji vanjske klime. To potvruje

bora (north-easterly wind). The air temperaturedropped in Cres and cold air currents caused adrop in temperature at MT2. The decrease inwind velocity that blew in changing directions(with the prevailing ones from the south quadrant)

between 12 and 15 February 2007 was followedby a steady rise in temperature. From 15 February2007 the northern winds prevailed. Their velocityrose and lasted until 17 February followed by amarked drop in temperature on the surface andunderground. After that period the wind velocitydecreased, the prevailing directions were S, SEand SSE, and the temperature gradually rose. Asimilar impact of bora on cave air temperaturewas recorded in urovia spilja in ilipi (Buzjak,2006b; 2006c). At MT1 oscillations do exist, butthey are considerably lesser due to the measurementpoint being further from the entrance and subject

to reduced impact of external conditions.Mean monthly air temperatures rose at regular

intervals from February towards August (Tab. 1,Fig. 5), with an increase on the surface followedby an increase in the cave (Fig. 6). Deviationsfrom average values were greater at MT2 which isevident from the temperature amplitude, standarddeviation (s) and variability coefficient (V). Thereason for this is the vicinity of the entrance and astronger input from the surface since the entranceis spacious and gated with horizontally placedmetal bars thus allowing the external air to flow

freely into the cave (much in the same way as thecave air freely flows out). That is further confirmedby the average air temperature at MT2 which ishigher than in remote parts of the cave that is dueto warm surface air input in the warm period of the

Tablica 1. Hod srednjih mjesenih temperatura zraka (C) u spilji (MT1 i MT2) te klimatolokoj postaji Cres zarazdoblje 1991.-2000. i 2007. godinuTable 1 Mean monthly air temperature trend (C) in the cave (MT1 and MT2) and at the climatological station Cresfor period 19912000 and 2007

Mjesec/Month MT1 MT2 Cres 1991.-2000. Cres 2007.II 11,36 9,81 9,4 11,8III 11,55 10,25 12,7 16,2IV 11,75 10,78 17,9 19,5V 12,22 12,04 21,7 23,6VI 12,55 13,52 24,4 25,7VII 12,91 14,75 24,8 23,6VIII 13,26 15,63 19,6 17,9X 12,23 12,40 18,6 19,8

s 0,72 2,28 5,81 4,90

V(%) 5,91 18,61 31,24 24,75

Izvor / Source: Meteorological and Hydrological Service, Zagreb


8/14

104


vrsta pozitivna korelacija (r = 0,9928) izmeutemperature MT2 i MT1 (Sl. 7). Ona je ujednopokazatelj da pukotinska cirkulacija zraka3 nemaznaajnijeg utjecaja na temperaturu MT1 nego daglavnina svjeeg zraka s povrine dolazi kroz ulaz.Na cirkulaciju prema MT1 utjecaja ima i silaznikarakter kanala, osobito u hladnijim danima kadapo dnu pritjee tei hladni zrak. Za turistikokoritenje pozitivno je takvo (iako minimalno)"provjetravanje" kanala, jer umanjuje utjecajporasta temperature zraka zbog osvjetljenja iulaska turistikih grupa.

Dnevne i srednje mjesene vrijednostitemperature zraka MT2 bile su nie nego na MT1 dodruge polovice svibnja. Nakon toga im vrijednostirastu iznad onih zabiljeenih na MT1. Na takvokretanje, osim pritjecanja toplijeg zraka izvana,

year. Based on the results of the above mentionedmeasurements in Cres (Fiedler, Buzjak, 1998)as well as measurements carried out in otherCroatian speleological phenomena (author'sresearch files), one would naturally assume that theair temperature at the cave entrance zone (MT2)during the cold parts of year would be lower incorrelation with the remote parts located further

form the entrance.The data in Table 1 shows that even at MT1 the

influence of external climate conditions existed.That was confirmed by the solidpositive correlation(r=0.9928) between MT2 and MT1 temperatures(Fig. 7). At the same time this was an indicator thatfissure air circulation3 had no considerable impacton MT1 temperature but that the bulk of freshsurface air entered through the cave entrance. Theair circulation towards MT1 was further affected

3 Cirkulacija zraka kroz uske i za ovjeka neprolazne

pukotine.

3 Air circulation through narrow and impassable fissures.

Slika 6. Linearna korelacija izmeu srednjih mjesenih temperatura (Cres, MT1 i MT2)Izvor: DHMZ, ZagrebFigure 6 Linear correlation between mean monthly temperatures (Cres, MT1 and MT2)Source: Meteorological and Hydrological Service, Zagreb


9/14

105


vjerojatno utjee i zagrijavanje stijena u nadslojuiznad kanala ije su naslage ovdje debele u prosjekusvega 3-4 m. Pojedini skokovi temperature moguisu zbog dotjecanja toplije vode s povrine (toplakia i prokapnica koja se zagrijava procjeivanjemkroz ugrijane stijene ljeti).

Ovisnost hoda srednje mjesene temperaturezraka o uvjetima na povrini jo je zornija akose izmjerene vrijednosti usporede s vanjskimpodacima klimatoloke postaje Cres (Hs=5 m; Sl.

5). Korelacija je pozitivna i vrsta (za razdoblje1991.-2000. r > 0,764). Promjene temperatureu spilji odraz su promjena na povrini. Porasttemperature zraka promatranog razdobljau podzemlju je sporiji pa se javlja kanjenjetemperaturnog maksimuma u podzemlju za onimna povrini.

by the downward inclined passage, particularlyduring colder days when there was the input ofcomparatively dense and sinking cold air. For thepurpose of tourist use, such passage "ventilation",although minimal, is considered to be a positivefeature since it lessened an increase in temperaturedue to the lighting system and cave visitors.

Diurnal and mean monthly air temperaturevalues at MT2 were lower than at MT1 until thesecond half of May. Afterwards their values rose

above those recorded at MT1. The cause of thistemperature trend, apart from the input of warmexternal air, is likely to be found in warming up ofthe overlying rock above the passage with averagethick as little as 3-4 m. Individual temperaturefluctuations are possible owing to thewarm surfacewater input (warm rain and drip water that warmsup during percolation through warmed up rock insummer).

The correlation of mean monthly air temperaturetrend and the surface conditions becomes clearerwhen the measured values are compared to the

Slika 7. Linearna korelacija izmeu temperature zraka MT1 i MT2Figure 7 Linear correlation between MT1 and MT2 air temperature


10/14

106


Slika 8. Hod srednjih dnevnih temperatura zraka, rosita i apsolutne vlanosti MT1Figure 8 MT1 mean diurnal air temperature, dew point and absolute humidity trend

Slika 9. Hod srednjih dnevnih temperatura zraka, rosita i apsolutne vlanosti MT2Figure 9 MT2 mean diurnal air temperature, dew point and absolute humidity trend


11/14

107


Rosite

Rosite je temperatura pri kojoj nastupakondenzacija vodene pare (Penzar, Penzar 1989).Ona se moe postii tako da se uz nepromijenjenu

koliinu vodene pare zrak ohlauje do zasienja.U spiljama do kondenzacije dolazi zbog hlaenjatoplijeg zraka u dodiru s hladnijim stijenama ilisedimentima na kojima se kao rezultat javlja spiljskarosa. Budui da je usko vezana uz vlanost zraka,u spiljama gdje je vlanost visoka temperaturarosita je gotovo jednaka kao i temperatura zraka.Odstupanja od srednjih vrijednosti vrlo su mala(Tab. 2.). U spilji (dalje od zone vanjskih utjecajau blizini ulaza) relativna vlanost zraka je 96-100% pa su temperatura zraka i rosita jednakihvrijednosti (Sl. 8. i 9.). Kondenzacija je primijeena

na stijenama, tlu i sigama oko ulaza.

Relativna i apsolutna vlanost zraka

U spilji su zabiljeena vrlo mala kolebanjarelativne vlanosti zraka. Najmanje vrijednostizabiljeene su na MT2 poetkom veljae kaonajhladnijem mjesecu u nizu u kojem su biljeene inie temperature zraka (Sl. 10.).

Vrijednosti vlanosti zraka u spiljama vezanesu uz hod temperature zraka, vlaenje stijena isedimenata pritjecanjem vode, te iznosima izmjene

energije izmeu zraka, vode, stijena i sedimenata.S porastom temperature zrak moe sadravati vievlage, dok ohlaivanjem dolazi do kondenzacije.Apsolutna vlanost raste s porastom temperaturezraka.

external data from the climatological station on Cres(Hs=5 m; Fig. 5). Correlation is positive and solid(for the period 1991-2000 r > 0.764). Changes inthe cave temperature reflected the surface changes.The increase in cave air temperature during the

observed period was slower, in comparison tothe surface values, and a delay of temperaturemaximum occurred.

Dew Point

Dew point is the temperature at whichcondensation of water vapour occurs (Penzar,Penzar 1989). Condensation in caves occurs asa result of cooling of warmer air that comes intouch with cooler rocks or sediments on whichcave dew is formed. Since it is closely linked to the

air humidity, in high humidity caves the dew pointtemperature approximated to the air temperature.Deviations from average values were slight (Tab. 2).In the cave (further from by the exterior conditionsinfluenced zone near the entrance) relative airhumidity was 96-100% resulting in equal valueof air and dew point temperature (Fig. 8 and 9).Condensation was noticed on passage walls, soiland speleothems around the entrance.

Relative and absolute air humidity

In the cave slight relative air humidity

fluctuations have been recorded. The minimumvalues were recorded at MT2 in the beginning ofFebruary, the coldest month in a series, duringwhich even lower air temperatures were recorded(Fig. 10).

The cave air humidity values correlate with theair temperature trend, rock and sediment moistureby means of percolating water inflow, and energyexchange values between air, water, rock andsediments. With an increase in temperature, air cancontain more humidity, whereas its cooling resultsin condensation. Absolute air humidity rises with

the increase in air temperature.

Tablica 2. Standardne devijacije (s) za temperaturu zraka (T), temperaturu rosita (), apsolutnu (av) i relativnu (u)

vlanost zraka Spilje u Belejskoj komunadiTable 2 Standard deviations (s) for air temperature (T), dew point temperature (), absolute (a

v) and relative (u) air

humidity in the Cave in Belejska komunada

MT1 MT2T(C) (C) a

v(g/m3) u (%) T(C) (C) a

v(g/m3) u (%)

s 0,64 0,67 0,47 0,05 2,06 2,06 1,41 0,19


12/14

108


Zakljuak

Spilja u Belejskoj komunadi ima tipinu spiljskumikroklimu ije su znaajke:

- nie vrijednosti temperature zraka te vievrijednosti relativne i apsolutne vlanosti zrakanego na povrini,

- visoka vlanost zraka tijekom cijelog razdoblja(najee 99-100%),

- manje dnevne, mjesene i sezonske oscilacijenjihovih vrijednosti od onih na povrini,

- oscilacije su najvee u blizini ulaza zbog pritjecanjahladnijeg zraka s povrine zimi i toplijeg ljeti,

- s udaljavanjem od ulaza oscilacije se smanjuju,

- kanjenje maksimuma temperature zraka upodzemlju za onima na povrini,

- u kanalu je zabiljeena pojava spiljske rose(pojaano u zoni ulaza).

Promatrano razdoblje 2007. godine na postajiCres je bilo toplije od viegodinjeg prosjeka (1991.-2000.) tako da su vjerojatno i spiljske temperaturevie nego to je njihov viegodinji prosjek.

U spilji je dokazan utjecaj vjetra na sniavanjetemperature zraka (bura u hladnijem dijelugodine). Glavnina zraka u spilju dolazi slobodnom

Conclusion

The Cave in Belejska Komunada has a typicalcave microclimate with the following features:

- lower air temperature values and higher relativeand absolute air humidity values than on surface,

- high air humidity during the entire period (inmost cases 99-100%),

- smaller diurnal, monthly and seasonal oscillationsfrom the surface ones,- oscillations are greatest near the entrance due tothe inflow of cooler air from the surface duringwinter and warmer air during summer,- going further from the entrance, the oscillations

are less pronounced,- a delay in maximum cave air temperature inrelation to the ones on the surface,

- in the passage the presence of cave dew wasrecorded (particularly in the entrance zone).

With respect to the surface air temperature,the observed 2007 period was above the averagerecorded in the 1991-2000 period, therefore it islikely that the cave temperatures reflected the samepattern.

Inside the cave the direct impact of wind on thedecrease in air temperature has been proven (bora

Slika 10. Usporedba dnevnog hoda temperature i relativne vlanosti zraka (u) MT1 i MT2 (4.-6. veljae 2007.)Figure 10 The comparison of diurnal temperature trend with relative air humidity (u) MT1 and MT2 (4-6 February2007)


13/14

109


cirkulacijom kroz prostrani ulaz pa ju je vanoosigurati i u sluaju turistikog iskoritavanja.Ljudi u spilji dovest e do porasta temperaturezraka i pojaanog roenja (te promjene drugihparametara) pa je bitno da se ulaz ne zatvara punim

vratima koja e onemoguiti normalnu cirkulacijuzraka i provjetravanje spilje. To je vano i stoga toje spilja niskog energetskog nivoa4 (Heaton, 1986)te je izuzetno osjetljiva na negativne antropogeneutjecaje. Nepravilno gospodarenje spiljom moeu kratkom vremenu dovesti do velikih promjenamikroklimatskih i drugih parametara za ijeje vraanje na prirodno stanje potrebno punovremena.

Prouavanje uvjeta kondenzacije u krkompodzemlju i mjerenja iznosa kondenzacijezasluuje veliku pozornost. Prema dosadanjim

spoznajama kondenzirana voda ima znaajnuulogu u okravanju i speleogenezi (Dublyansky,Dublyansky, 2000). Ona korozivno djeluje namatinu stijenu te ima utjecaja na oblikovanje raznihspiljskih denudacijskih mikroreljefnih oblika, ali isiga (npr. koraloidi). Spiljska rosa u kombinacijis neadekvatnom rasvjetom moe dovesti dopojave flore5 na stijenama i sigama. Biokemijskimprocesima i njihovom agresivnim produktimadolazi do intenzivnijeg nagrizanja povrine. Osimtoga, alge svojom pojavom naruavaju estetskidoivljaj, naroito kada obrataju sige. Negativne

antropogene utjecaje koji se javljaju pri turistikom

in the colder part of year). Given that the majoramount of air gets in the cave via free circulationthrough the spacious entrance, it is necessaryto make sure that this free air circulation isundisturbed in case of tourist usage. The presence

of visitors inside the cave will result in an increasedair temperature and intensified formation of cavedew (as well as changes in other parameters) so itis vital to leave the entrance ungated in order notto prevent normal air circulation and ventilationin the cave. Equally important is the fact that thisis a low energy level4cave (Heaton, 1986), highlysusceptible to negative antropogenous effects.Consequently, in a short time an unsuitable cavemanagement could cause profound changes inmicroclimatic and other parameters whereas theefforts to restore them to their natural state wouldrequire quite a long time.

A research on condensation conditions inkarst underground area and on the amount ofcondensation measured deserves to be takenseriously. According to our understanding so far,condensed water is an important factor duringkarstification and speleogenesis (Dublyansky,Dublyansky, 2000.). It corrodes the rock awayand affects the formation of various cave denudatedmicrorelief forms, including speleothems (e.g.coral-like formations). Cave dew combined withinadequate lighting may result in the growth offlora5 on rocks and speleothems. Due to biochemical

processes and resulting aggressive products, the

4 Podjela speleolokih pojava prema energentskim nivoimapomona je metoda u odreivanju podnoljivog kapaciteta.Pogodna je za spilje u kojima nije obavljeno sustavnomjerenje geoekolokih parametara potrebnih za planiranjeturistikog koritenja (Buzjak 2006 a). Energetski nivoiodreeni su intenzitetom djelovanja prirodnih sila kojenakon turistikih posjeta (ili openito antropogenihutjecaja) spilju vraaju u njeno prirodno stanje. Dopromjena dolazi izmjenom energije ili promjenama univoima energije. Speleoloke pojave niskog energentskog

nivoa najosjetljivije su na antropogene utjecaje zbog slabogdjelovanja prirodnih sila. U njima najvei intenzitet meuprirodnim procesima moe biti npr. kapanje prokapnicekoje nije dovoljno za vraanje spiljskog prostora u prirodnostanje (kao npr. poplava kanala ili snano strujanje zraka).Posjet tom tipu spilja moe imati ozbiljne posljedice jer ukratkom vremenskom razdoblju moe doi do izrazitihpromjena fiziko-kemijskih parametara (temperature ivlanosti zraka, koncentracije CO2, unos spora i prainei sl.) za ije je vraanje na prirodno stanje zbog sporostiprirodnih procesa potrebno puno vremena.5 Njem. Lampenflora; najee alge i mahovine. Podneadekvatnom rasvjetom misli se na obine arulje ireflektore koji jako zagrijavaju zrak, stijene i sedimente tesvojim svjetlosnim karakteristikama potiu razvoj flore.

Alternativa je tzv. hladno svjetlo.

4 Classification of speleological phenomena according totheir energy levels is an auxiliary method used to determinea carrying capacity. It is suitable for caves in which nosystematic measurement of the required geoecologicalparameters was conducted for the purpose of planning itstourist usage (BUZJAK, 2006a). Energy levels are determinedby the intensity of natural processes that can restore a caveto its natural state after tourist visits (or antropogenousimpact in general). The changes occur as a result of energyexchange or variations in energy levels. Speleologicalphenomena with a low energy level are the most sensitiveto antropogenous impacts due to their feeble naturalprocesses. Their strongest natural process intensity could befor example dripping of ground water which is insufficientto restore the cave environment to its natural state (e.g.passage flooding or strong air currents). A visit to thatparticular type of cave could have detrimental effects on thecave environment because in a quite short period of timedramatic alterations in physical and chemical parameters(air temperature and humidity, CO2 level, spore and dustinput etc.) may occur and the restoration to the originalstate, due to the slowness of natural processes involved,would take a long time.5 Germ. Lampenflora; mostly algae and mosses. Theinadequate lighting refers to garden variety bulbs andspotlights which not only considerably warm up air, rocksand sediments but also allow flora to grow. Alternative is

the "cold" light.


14/14

110


koritenju mogue je ublaiti kontinuiranimpraenjem mikroklimatskih parametara (osnovnisu temperatura i vlanost zraka), odreivanjemturistikog kapaciteta spilje i njenih dijelova6 teodabirom hladne rasvjete koja ne daje uvjete za

razvoj flore.

Zahvala

Ovaj rad je nainjen uz potporu projekta MZO"Geomorfoloka i geoekoloka istraivanja kraRH", broj 119-1191306-1305.

surface corrosion is intensified. In addition, thedevelopment of algae hinders the cave's aestheticappeal, especially when found on speleothems. It islikely that the negative antropogenous impact dueto the cave tourist usage could be minimized by

means of continuous monitoring of microclimaticalparameters (basic ones being air temperature andhumidity), determining tourist capacity of the caveand its parts6 and by opting for low-heat lights thatdo not support the plant development.

Acknowledgments

This study was carried out with the supportof Ministry of science, education and sports:Geomorphological and geoecological research onKarst features in the Republic of Croatia project,No. 119-1191306-1305.

6 Turistiki kapacitet spilje odreen je gornjim brojem turistakoji nee izazvati kritine promjene ekolokih parametaraspilje (promjene fiziko-kemijskih svojstava zraka i vode),bioloko oneienje, fiziko oteenje i unoenje otpada

(BUZJAK, 2006a).

6 The cave visitors capacity is the maximum number ofvisitors whose presence in a cave will not dramatically alterits ecological parameters (variations in physical and chemicalcharacteristics of water and air), biological pollution, physical

damage and rubbish dumping (BUZJAK, 2006a).

LITERATURA /LITERATURE

Buzjak, N. (1997): Krko podzemlje otoka Cresa, Geografski horizont, 2/1997, 109-117.

Buzjak, S. (2001): Ekoloka i floristika obiljeja ulaznih dijelova jama i spilja u kru Hrvatske, Disertacija,1-150, PMF, Bioloki odsjek, Zagreb.

Buzjak, N. (2006a): Geomorfoloke i speleoloke znaajke umberake gore i geoekoloko vrednovanjeendokrkog reljefa. Disertacija, PMF, Geografski odsjek, Zagreb.

Buzjak, N., (2006b): Geomorfoloke, speleomorfoloke, hidroloke i meteoroloke znaajke uroviapilje. U: Kovaevi, T. (ur.), 2006.: Elaborat o speleolokim, geomorfolokim, meteorolokim,paleontolokim, arheolokim i biospeleolokim istraivanjima, te geodetskom i fotografskom snimanjuurovia jame - pilje, DDISKF, 1-39, Zagreb.

Buzjak, N. (2006c): Speleomorfoloke i hidroloke znaajke urovia pilje, Hrvatski geografski glasnik,68/2, 57-72.

Dublyanski, V. N., Dublyanski, Y. N., (2000): The Role of Condensation in Karst Hydrogeology andSpeleogenesis. U: Klimchouk, A., Ford, D., Palmer, A., Dreybrodt, W. (ur.): Speleogenesis. Evolution ofKarst aquifers, 100-112, National Speleological Society, Huntsville.

Fiedler, S., Buzjak, N. (1998): Speleobotanika istraivanja otoka Cresa, Zbornik "Prirodoslovnaistraivanja rijekog podruja", Prirodoslovna istraivanja, 1, 387-395

Heaton, T., (1986): Caves. A tremendous range in energy environments on Earth, NSS News, 44(8), 301-304.

Maga, N. (1968): OGK, list Cres, SGZ, Beograd

Penzar, I., Penzar, B. (1989): Agroklimatologija, kolska knjiga, Zagreb, 97-101.

Documents

NENAD BUZJAK - MIKROKLIMA KAO KOMPONENTA GEOEKOLOŠKOG VRJEDNOVANJA SPILJA – PRIMJER SPILJE U BELEJSKOJ KOMUNADI (BELEJ, OTOK CRES)