REVISED THORNTHWAITE CLIMATE CLASSIFICATION FOR MONTENEGRO (1961–2020)

The main objective of this paper is to perform a bioclimatic delineation of regions with varying degrees of humidity in Montenegro using the Thornthwaite Moisture Index. A dataset spanning 60 years (1961–2020) was utilized, comprising air temperature and precipitation sums from 18 meteorological stations (MS). The homogeneity of the data was examined using the methods MASH v3.02 and MISH v1.02. For determining the climatic classification categories, the 60-year period (1961–2020) was divided into two standard climatic sub-periods: 1961–1990 and 1991–2020, to detect any changes in the spatial distribution of climates. The analysis was conducted on a multi-year monthly level. Calculations were performed using the software package PAST 4.13, and maps were drawn using QGIS 2.8.1. For the mathematical modeling of the cartographic representation of Thornthwaite’s climatic classification, the Inverse Distance Weighted (IDW) geostatistical interpolation method was used. The hythergraph method was used for graphical representation of stations as typical representatives of climates in the Thornthwaite classification system. The results obtained for the 60-year period indicate that the Thornthwaite Moisture Index (PE) has values ranging from 631.5 (MS Crkvica), indicating a humid (A) climate with forest and persistent rain, to 95 (MS Pljevlja), indicating a humid (B) climate with forest vegetation. The majority of MS in Montenegro show values of this index that classify them into a humid (A) climate. The average value of the Thornthwaite Moisture Index (PE) at 18 MS for the 60-year period is 198.3, indicating that the climate of Montenegro during this period was humid with forest and persistent rain. According to the Thornthwaite Moisture Index (PE), the lowest effects were detected at stations in the north and northeast of Montenegro (MS Pljevlja, MS Berane, MS Bijelo Polje, MS Rožaje, and MS Plav), as well as at MS Ulcinj and MS Bar, while the highest effects were recorded at stations in the southwest and west of the territory. This can be related to the spatial distribution and precipitation regime in Montenegro. For each MS, Thornthwaite’s climatic formula was determined for the 60-year and two 30-year sub-periods, with changes in the climatic formula between the observed periods specifically marked.