Vpliv meteoroloških in vegetacijskih parametrov na prestrezanje padavin : doktorska disertacija

Zabret, Katarina (author), Šraj, Mojca (mentor), Rakovec, Jože (co-mentor)

Ob stiku z vegetacijo se padavine razdelijo na prestrežene padavine, ki tal nikoli ne dosežejo, saj takoj po padavinskem dogodku izhlapijo nazaj v ozračje, ter na prepuščene padavine in odtok po deblu, ki tla dosežejo na različne načine. Kakšni so deleži posameznih komponent procesa prestrezanja padavin, je odvisno od meteoroloških spremenljivk, ki opisujejo lastnosti padavinskega dogodka, in od vegetacijskih spremenljivk, ki podajajo lastnosti dreves. Poznavanje in razumevanje vplivov teh spremenljivk je pomembno pri ovrednotenju procesa prestrezanja padavin in njegovega vpliva na ostale naravne procese, kot so površinski odtok, erozivnost padavin, erozija tal, vpliv na višino podtalnice in premeščanje hranil v tleh. Prepuščene padavine in odtok po deblu smo merili v manjšem parku v Ljubljani med 1. januarjem 2014 in 30. junijem 2017 pod navadno brezo (Betula pendula Roth.) in črnim borom (Pinus nigra Arnold). V tem obdobju smo spremljali tudi meteorološke in vegetacijske spremenljivke. V prvem delu disertacije smo predstavili proces prestrezanja padavin, opisali, kako se prepuščene padavine spreminjajo v prostoru in kako prestrezanje padavin vpliva na zmanjševanje površinskega odtoka. Podrobno smo opisali meteorološke in vegetacijske spremenljivke, ter navedli, kako so bile že vključene v analize procesa prestrezanja padavin v drugih raziskavah. Predstavili smo raziskovalno ploskev, na kateri smo izvajali meritve in opisali uporabljene merske metode ter metode za analizo podatkov. V drugem delu disertacije smo prikazali rezultate meritev padavin na prostem, prepuščenih padavin in odtoka po deblu, izračunane vrednosti prestreženih padavin ter izmerjene vrednosti meteoroloških in vegetacijskih spremenljivk. Ovrednotili smo tudi vpliv opazovanih dreves na zmanjšanje površinskega odtoka v urbanem okolju. Vpliv spremenljivk na proces prestrezanja padavin smo analizirali za prostorsko porazdelitev prepuščenih padavin pod drevesnimi krošnjami, za časovno spremenljivost prepuščenih padavin tekom razvoja dogodka in za povprečne vrednosti spremenljivk glede na dogodke. Ugotovili smo, da so vplivi meteoroloških in vegetacijskih spremenljivk med seboj tesno povezani. Glede na fenofaze sta bili najbolj vplivni meteorološki spremenljivki količina padavin v obdobju vegetacije in intenziteta padavin v obdobju mirovanja, kar je povezano tudi z indeksom listne površine, skladiščno zmogljivostjo krošnje in skorje ter z razporeditvijo vej. Zaradi tega se je vzorec prostorske porazdelitve prepuščenih padavin pod brezo spremenil v omenjenih fenofazah. Pomemben vpliv pa je imela tudi mikrostruktura padavin; pojav večjih in hitrejših dežnih kapljic je povečal prepuščanje padavin pri boru, v primeru obeh dreves pa je vplival na začetek prepuščanja padavin.

• Language: Slovenian
• Keywords: grajeno okolje, varstvo okolja, prestrežene padavine, prepuščene padavine, odtok po deblu, navadna breza, Betula pendula Roth., črni bor, Pinus nigra Arnold, mikrostruktura padavin
• Work type: Doctoral dissertation
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Year: 2018
• PID: 20.500.12556/RUL-101711
• COBISS.SI-ID: 8468577
• Publication date in RUL: 30.06.2018

Secondary language

• Language: English
• Title: Influence of meteorological and vegetation parameters on rainfall interception : doctoral thesis

Abstract

The rainfall falling above the vegetation is divided into intercepted rainfall not reaching the ground and into throughfall and stemflow reaching the ground in different ways. The share of each rainfall interception component depends on meteorological variables describing properties of rainfall events and vegetation variables giving the properties of the tree. Knowing and understanding the influences of those variables is important for estimation of the rainfall interception process and its influence on other natural processes such as surface runoff reduction, increase of rainfall erosivity, reduction of soil erosion, enrichment of ground water, and nutrient cycle. Throughfall and stemflow were measured in a small park in Ljubljana between 1 January 2014 and 30 June 2017 under the common silver birch (Betula pendula Roth.) and Austrian pine (Pinus nigra Arnold) trees. In the same period meteorological and vegetation variables were also measured. In the first part of this dissertation, we described the process of rainfall interception, the changes of throughfall across space and time, and the influence of rainfall interception on surface runoff reduction. Meteorological and vegetation variables were presented in detail and their consideration in other studies was stated. The study plot where the measurements were taken was also described, and the measurement and data analysis techniques were presented. In the second part of the dissertation, the results of precipitation in the open, throughfall and stemflow were presented, the estimated values of rainfall interception were given, and the measured values of meteorological and vegetation variables were listed. We also estimated the influence of the trees on surface runoff reduction in the urban area. The influence of the variables on the components of rainfall interception was analysed for spatial distribution of throughfall under the canopies, for temporal variability of throughfall with the development of the event, and for the average values of the variables per events. We have shown that meteorological and vegetation influences interact closely. According to phenoseasons, the most influential meteorological variables were the amount of precipitation in the vegetation period and the rainfall intensity in the dormant period. This depends also on the leaf area index, canopy storage capacity, water bark storage capacity, and branch position. These variables also induced the changes in the spatial pattern of throughfall under the birch tree's canopy in the phenoseasons. Additionally, the rainfall microstructure also significantly affected rainfall partitioning. Larger and faster raindrops initially increased throughfall in the case of the pine tree, and induced the start of throughfall under both tree species.

• Keywords: building environment, rainfall interception, throughfall, stemflow, common silver birch, Betula pendula Roth., Austrian pine, Pinus nigra Arnold, drop size distribution (DSD)