| 165 | | 67/2 | RECENZIRANI ČLANKI | PEER-REVIEWED ARTICLES V G 2023 GEODETSKI VESTNIK | letn. / Vol. 67 | št. / No. 2 | KLJUČNE BESEDE KEY WORDS leaf phenology, seasonal phases, time series, NDVI, MODIS listna fenologija, sezonske faze, časovne vrste, NDVI, MODIS Tis study investigates the usefulness of MODIS (Moderate Resolution Imaging Spectroradiometer) satellite imagery for determining the start, end, and length of the growing season of selected deciduous tree species. Vegetation indices derived from satellite imagery provide consistent observations in a similar temporal sequence and are useful for determining phenological phases. Using time series of NDVI (Normalised Diference Vegetation Index) vegetation index from MODIS imagery, phenological patterns were detected at several points in Slovenia and diferent approaches to determine seasonal phases were compared. In addition, the derived seasonal phases with feld phenological and meteorological data were also compared. It has been found that the success of determining phenological phases from satellite imagery depends on many factors: the spatial resolution of the satellite data, the smoothing method for the time series data, the method for determining phenological parameters, and the feld data used for comparison. Te results of the study show that phenological phases determined by using MODIS data with a resolution of 250 m best match the phenological data maintained by the Slovenian Forestry Institute using the mean seasonal values method. UDK: 528.7/.8:551.506.8:519.172.1 Klasifkacija prispevka po COBISS.SI: 1.01 Prispelo: 5. 2. 2023 Sprejeto: 24. 5. 2023 DOI: 10.15292/geodetski-vestnik.2023.02.165-180 SCIENTIFIC ARTICLE Received: 5. 2. 2023 Accepted: 24. 5. 2023 DETERMINING PHENOLOGICAL PHASES OF SELECTED TREE SPECIES WITH MODIS TIME-SERIES DATA Urška Kanjir, Mitja Skudnik, Žiga Kokalj DOLOČEVANJE FENOLOŠKIH FAZ IZBRANIH DREVESNIH VRST S ČASOVNIMI VRSTAMI POSNETKOV MODIS V študiji smo preučili uporabnost satelitskih posnetkov MODIS (angl. Moderate Resolution Imaging Spectroradiometer) za določevanje začetka, konca in dolžine rastne sezone izbranih drevesnih vrst listavcev. Vegetacijski indeksi, pridobljeni iz satelitskih posnetkov, zagotavljajo konsistentna opazovanja v podobnem časovnem zaporedju in so primerni za določevanje fenoloških faz. Z uporabo časovnih vrst vegetacijskega indeksa NDVI (normiran diferencialni vegetacijski indeks) iz posnetkov MODIS smo zaznavali fenološke vzorce na več točkah po Sloveniji in med seboj primerjali različne pristope določevanja sezonskih faz. Pridobljene sezonske faze smo primerjali s terenskimi fenološkimi in meteorološkimi podatki. Ugotovili smo, da je uspešnost določevanja fenoloških faz na podlagi satelitskih posnetkov odvisna od mnogih vplivov: prostorske ločljivosti satelitskih podatkov, izbire metode glajenja časovnih vrst podatkov, izbire metode določevanja fenoloških parametrov in izbire terenskih podatkov za primerjavo. Rezultati študije kažejo, da fenološke faze, pridobljene s satelitskimi posnetki MODIS ločljivosti 250 m, najbolje sovpadajo s fenološkimi podatki, ki jih vodi Gozdarski inštitut Slovenije z uporabo metode srednje sezonske vrednosti. Urška Kanjir, Mitja Skudnik, Žiga Kokalj | DOLOČEVANJE FENOLOŠKIH FAZ IZBRANIH DREVESNIH VRST S ČASOVNIMI VRSTAMI POSNETKOV MODIS | DETERMINING PHENOLOGICAL PHASES OF SELECTED TREE SPECIES WITH MODIS TIME-SERIES DATA | 165-180 | ABSTRACT IZVLEČEK SI | EN