Vpliv prestrezanja padavin na mikrostrukturo padavin

diplomska naloga št.: 125/B-VOI

Lana Radulović (Author), Mojca Šraj (Mentor), Nejc Bezak (Co-mentor)

Abstract

Prestrezanje padavin, proces pri katerem vegetacija zadržuje padavine, v veliki meri vpliva na naravne procese (npr. erozijo tal). Pri obravnavanju padavin je pomembno upoštevati tudi njihovo mikrostrukturo, saj imajo posamezni padavinski dogodki različno število kapljic, ki se pojavljajo v različnih velikostih in padajo z različno hitrostjo. Podatke o padavinah smo pridobili s pomočjo 1-minutnih meritev treh optičnih disdrometrov (pod krošnjo breze, pod krošnjo bora in nad krošnjama). Obravnavano obdobje (med 12. julijem 2022 in 16. februarjem 2023) smo razdelili na 48 padavinskih dogodkov in nato za posamezne dogodke izračunali čas trajanja, količino padavin, povprečno intenziteto padavin in mikrostrukturo dežnih kapljic (velikost, hitrost in število kapljic). Izračunali smo kinetično energijo (KE), maksimalno 30-minutno intenziteto (max I30) in dejavnik erozivnosti padavin (R). Vse spremenljivke smo izračunali za podatke nad krošnjama in pod njima. Iz rezultatov je razvidno da se prestrezanje padavin s časom trajanja dogodkov zmanjšuje tako pri brezi kot pri boru. Kapljice so se pri prehodu skozi drevesne krošnje v obdobju vegetacije povečale. V obdobju mirovanja pa so se zmanjšale, vendar se je premer kapljic glede na celotno obravnavano obdobje kljub vsemu povečal (pod brezo za 46 %, pod borom za 25,5 %). Hitrost kapljic se je pod borom v povprečju zmanjšala za 38 %. Pod brezo pa se je malenkost povečala za 0,7 %, kar je posledica povečanja povprečne hitrosti pod njo v obdobju mirovanja (za 7 %). Iz dobljenih rezultatov smo ugotovili da ima prestrezanje padavin relativno velik vpliv na erozijo tal, saj se je dejavnik erozivnosti padavin (R) zaradi prestrezanja precej zmanjšal (pod brezo za 42,6 %, pod borom za 89,9 %).

Keywords

gradbeništvo;diplomske naloge;UNI;VOI;B-VOI;padavine;mikrostruktura padavin;prestrezanje padavin;erozivnost padavin;disdrometer;porazdelitev padavinskih delcev (DSD);

Data

Language:	Slovenian
Year of publishing:	2023
Typology:	2.11 - Undergraduate Thesis
Organization:	UL FGG - Faculty of Civil and Geodetic Engineering
Publisher:	[L. Radulović]
UDC:	556.12:57.012.3(043.2)
COBISS:	178402563
Views:	212
Downloads:	32
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	ǂThe ǂinfluence of precipitation interception on the microstructure of precipitation
Secondary abstract:	Precipitation interception, the process by which various vegetation retains precipitation, greatly affects natural processes (e.g. soil erosion). When dealing with precipitation, it is important to consider the microstructure of precipitation, since precipitation is a process consisting of a finite number of individual drops that appear in different sizes and fall at different velocities. Precipitation data were obtained with the help of 1-minute measurements of three disdrometers (under the birch canopy, under the pine canopy and above them). The considered period (between July 12, 2022 and February 16, 2023) was divided into 48 rainfall events, and then the rainfall duration, amount of precipitation, average intensity of precipitation, and microstructure of raindrops (size, velocity, and number of drops) were calculated for individual events. Finally, we calculated kinetic energy (KE), maximum 30-minute intensity (max I30) and rainfall erosivity factor (R). All variables were calculated for data above and below both canopies. It can be seen from the results that the interception of precipitation decreases with the duration of the events for both birch and pine tree. The size of droplets increased as they passed through the tree canopy during the vegetation season. During the leafless period, however, they decreased, but the diameter of the drops increased compared to the entire considered period (under the birch tree by 46 %, under the pine tree by 25.5 %). Droplet velocity decreased on average by 38 % under the pine tree. Under the birch tree, however, it increased by 0.7 %, which is the result of an increase in the average speed under it during the dormant period (by 7 %). From the obtained results, we found that the rainfall interception has a great influence on soil erosion, since the rainfall erosivity factor (R) was significantly reduced when raindrops passed through both tree canopies.
Secondary keywords:	graduation thesis;civil engineering;rainfall;rainfall microstructure;rainfall interception;rainfall erosivity;disdrometer;drop size distribution (DSD);
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Ljubljani, Fak. za gradbeništvo in geodezijo
Pages:	XVIII, 56 str., [54] str. pril.
ID:	22264491