Summary
The aim of this diploma thesis was to monitor changes in value of the effective temperature and its dependence on relief. The thesis also examines the impact of high vegetation on the temperature values. In the study area the phenological observation of selected trees was done five times. The study area is part of Vysoké Pole village, which is situated in southeast Moravia in the Czech Republic.
First, digital elevation model (DEM) was created from airborne laser scanning data and analysed in GIS (Geographic Information System). Slope, aspect and area solar radiation was calculated from DEM to characterize the area. These characteristics were used for determination of the locations of two sensors. These two sensors were placed on the northeast slope in the end of May 2012. Other two sensors, situated on southwest slope, have been measuring the air temperature since 2011.
In the next part of the thesis, the data from sensors were processed. The temperature values measured at 7 a.m., 2 p.m. and 9 p.m. were used for calculating the daily mean temperature for each day of the year 2012. The effective temperature was derived from the daily mean temperature by subtracting 5 °C, which is the value of biological minimum. Then the effective temperature sums (ETS) were computed. These sums are usually used for prediction of the phenological phases. ETS were then interpolated in the study area with involved values of elevation and height of high vegetation.
It was revealed that the elevation and the amount of vegetation have the main influence on the air temperature values. Even though two of the sensors were on northeast slope, they recorded higher temperature values than the sensors oriented towards the southwest. It was probably caused by their lower altitudes. There was also the difference between locations on the meadow and places protected by high vegetation.
The phenological phases of selected trees, which are situated nearby the sensors, were observed on 26th June, 1st August, 3rd September, 17th September and 10th November 2012. Identified phenophases of oaks and pines correspond to state of the average values of the onset of phenological stages in years 1991 – 2010 identified by the Czech Hydrometeorological Institute. However, it would be necessary to control the trees much more often for more precise identification of the date of phenophases onset.