1826 KB0 KB199920252023Bezak, NejcRadulović, LanaŠraj, Mojcaletnik:36številka:64str. 57-79DOI:10.15292/acta.hydro.2023.04ISSN:1581-0267COBISSID_HOST:187610883URN:URN:NBN:SI:doc-60MOHU4XslFakulteta za gradbeništvo in geodezijoActa hydrotechnicabirchblack pinebrezačrni bordisdrometererozivnost padavinmikrostruktura padavinprestrezanje padavinrainfall erosivityrainfall interceptionrainfall microstructurSloveniaSlovenijaVpliv vegetacije na mikrostrukturo in erozivnost padavin| the influence of vegetation on the microstructure and erosivity of precipitation|The process of precipitation interception, in which vegetation retains precipitation, has a major influence on natural processes such as soil erosion. Assessing this influence requires measurements of the microstructure of precipitation using modern instruments that allow measurements of the velocity, size, and number of raindrops. The precipitation microstructure data were obtained using 1-minute measurements from three optical disdrometers placed under the birch canopy, under the black pine canopy and above the canopies. In the period under consideration between 12 July 2022 and 16 February 2023, 48 rainfall events were recorded, for which the duration, the amount of precipitation, the average intensity of precipitation, and the characteristics of the raindrops (size, velocity, and number of drops) were calculated. Additionally, the kinetic energy (KE), the maximum 30-minute intensity (max I30), and the rainfall erosivity factor (R) were calculated. All these variables were calculated for measurements above and below the tree canopies. The results show that the proportion of intercepted precipitation decreases with the duration of the events for both birch and pine. Droplets increased on average during the leafed period, as they passed through the tree canopy, and decreased during the leafless period. During the entire period, the diameter of the droplets increased on average by 46% under birch and by 26% under black pine. The droplet velocity decreased on average by 38% under the pine, while it increased minimally under the birch by 1%, which is the result of an increase in the average velocity under the birch during the leafless period by 7%. The analysis of the results shows that the rainfall interception has a large impact on soil erosion, as, for example, the rainfall erosivity factor (R) under birch decreased by 43% and under pine by 90%Proces prestrezanje padavin, pri katerem vegetacija zadržuje padavine, v veliki meri vpliva na naravne procese, kot je erozija tal. Za ovrednotenje tega vpliva so potrebne meritve mikrostrukture padavin s sodobno merilno opremo, ki omogoča spremljanje hitrosti, velikosti in števila dežnih kapljic. Podatke o mikrostrukturi padavin smo pridobili s pomočjo 1-minutnih meritev treh optičnih disdrometrov, nameščenih pod krošnjo breze, pod krošnjo črnega bora in nad krošnjami dreves. V obravnavanem obdobju med 12. julijem 2022 in 16. februarjem 2023 smo zabeležili 48 padavinskih dogodkov, za katere smo izračunali čas trajanja, količino padavin, povprečno intenziteto padavin in lastnosti dežnih kapljic, tj. velikost, hitrost in število kapljic. Dodatno smo izračunali še kinetično energijo (KE), maksimalno 30-minutno intenziteto (max I30) in dejavnik erozivnosti padavin (R). Vse omenjene spremenljivke smo izračunali za meritve nad krošnjam i dreves in pod njimi. Rezultati kažejo, da se delež prestreženih padavin s časom trajanja dogodkov zmanjšuje tako pri brezi kot pri boru. Kapljice so se pri prehodu skozi drevesne krošnje v obdobju vegetacije v povprečju povečale, v obdobju mirovanja vegetacije pa zmanjšale. V celotnem obravnavanem obdobju se je premer kapljic v povprečju povečal pod brezo za 46 %, pod borom za 26 %. Hitrost kapljic se je pod borom v povprečju zmanjšala za 38 %, pod brezo pa povečala za 1 %, kar je posledica povečanja povprečne hitrosti pod brezo v obdobju mirovanja za 7 %. Analiza rezultatov kaže, da ima prestrezanje padavin velik vpliv na erozijo tal, saj se je npr. dejavnik erozivnosti padavin in odtoka (R) zaradi spremenjenih lastnosti kapljic zmanjšal pod brezo za 43 %, pod borom pa kar za 90 %TEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za gradbeništvo in geodezijo