The differential interferometric synthetic aperture radar (DInSAR) method is based on phase variation between the complex value of pixels of timely separated scenes in interferometric SAR pairs. This ...phase variation has five components: surface topography, curvature of planet’s surface, terrain displacement, volume scatterers, and atmospheric propagation effects. The terrain displacement is the main product of the DInSAR method, while the last two effects are unpredictable and bring inaccuracy into the terrain displacement measurements. In this work, the propagation conditions in the troposphere and ionosphere were studied during two DInSAR measurements examining the Zagreb 22 March 2020 earthquake, with terrain raising of up to +3 cm at the epicenter. For the troposphere, the vertical profile of the modified refraction index, which incorporates local curvature change with height, was reconstructed using aerological balloon probing data. Ionospheric conditions were determined based on total electron content (TEC) calculated from the Croatian positioning system (CROPOS) and global navigation satellite system (GNSS) reference stations’ measurements. One of the DInSAR measurements was conducted in unfavorable tropospheric refractive conditions, which resulted in an overall bias of −2 cm. The variability of propagation conditions indicates the need for examining the atmospheric propagation effects when calculating terrain displacements using the DInSAR method. The results of DInSAR indicate slight displacements, comparable with the amplitude of atmospheric variations, and should therefore be approached with caution.
Defence capabilities have always been heavily dependent on technological capabilities. This dependence is significantly emphasized nowadays due to the very rapid advancement of science and technology ...relevant to defence, and especially due to the emergence of disruptive technologies. However, emerging and disruptive technologies are well known throughout human history (fire, wheel, metals, gunpowder, external and internal combustion engines, etc.). Today, the cycle of emergence, application and response to the EDT is much faster, due to globalisation and maturation of information technologies. Smaller countries, because of their modest industrial and technological base at the national level, have problems to follow the emerging and disruptive technologies. In modern civilization, the military is losing its traditional centuries-old role as a privileged customer for purchasing new, technologically advanced products and must face competition in the open market. In this case, defence must be actively involved in monitoring and predicting technological trends, with an emphasis on disruptive technologies. Countries, especially those with strong armed forces and a long military tradition, have been doing this for a long time, but supranational activities (NATO and the EU) are relatively recent. These supranational activities are an important complement to national efforts and it is recommended that they should not be neglected by smaller NATO and EU member states.
The impact of mesoscale structures on the occurrence of anomalous propagation (AP) conditions for radio waves, including ducts, superrefractive, and subrefractive conditions, was studied. The chosen ...meteorological situations are the bora wind and the sporadic sea/land breeze (SB/LB) during three selected cases over a large portion of the northern Adriatic. For this purpose, we used available radio soundings and numerical mesoscale model simulations (of real cases and their sensitivity tests) at a horizontal resolution of 1.5 km and 81 vertical levels. The model simulated the occurrences of AP conditions satisfactorily, although their intensities and frequency were underestimated at times. Certain difficulties appeared in reproducing the vertical profile of the modified refractive index, which is mainly dependent on the accuracy of the modeled humidity. The spatial distributions of summer AP conditions reveal that the surface layer above the sea (roughly between 30 and 100 m asl) is often covered by superrefractive conditions and ducts. The SB is highly associated with the formations of AP conditions: (i) in the first 100 m asl, where trapping and superrefractive conditions form because of the advection of cold and moist air, and (ii) inside the transition layer between the SB body and the elevated return flow in the form of subrefractive conditions. When deep convection occurs, all three types of AP conditions are caused by the downdraft beneath the cumulonimbus cloud base in its mature phase that creates smaller but marked pools of cold and dry air. The bora wind usually creates a pattern of AP conditions associated with the hydraulic jump and influences distribution of AP conditions over the sea surface.
Key Points
Anomalous propagation conditions for radio waves are simulated by a mesoscale numerical model
A large influence of the bora wind, sea/land breeze, and moist convection was observed
A bora pattern in anomalous propagation distribution has been found
Aerological balloon soundings are an abundant and reliable source of modified refractive index profiles. A time series spanning 15 years, collected from 4 Adriatic aerological stations, shows ...frequent anomalous propagation (anaprop) phenomena over the coast of the Adriatic Sea: radio ducts, superrefractions and subrefractions. Radio ducts are the rarest phenomena, but they have the most dramatic effects on propagation. Radio ducts generally occur in the lower third of the troposphere. Superrefractions are the most frequent anaprop phenomena, occurring mostly in the lower half of the troposphere. Subrefractions occur frequently in cold and dry air higher in the atmosphere; therefore, the vertical distribution shows a significant number of elevated subrefractions. Rare cases of subrefractions in the stratosphere also occur. All anaprop phenomena show distinct annual cycles in both number and vertical distributions.
► 15 years long series of refractive profiles over Adriatic Sea. ► Anomalous phenomena vertical distributions. ► Annual variations of anomalous propagations.
Zaštita okoliša tijekom provedbe vojnih aktivnosti u obalnom području na primjeru Rta Kamenjak obuhvaća sagledavanje i definiranje suvremenih izazova i strategije zaštite važnih interesa RH kao ...suverene države na primjeru vojnog modela uporabe i zaštite vrijedne mikro-lokacije na Jadranu kao što je zaštićeno područje Rt Kamenjak. U početnom dijelu poglavlja je opisana flora i fauna na kopnenom i morskom prostoru te su opisane odgovornosti, mjere i postupci svih korisnika radi zaštite okoliša. Opširnije je opisano područje Kamenjaka koje je zbog svojih posebnosti proglašeno značajnim krajobrazom. Opisani su uvjeti uporabe i zaštite prostora, područja primjene posebnih mjera uređenja i zaštite prostora uključujući položaj i posebnosti s kvantitativnim pokazateljima, koji su definirani Prostornim planom Istarske županije. Kako bi se što bolje razumio odnos vojne organizacije pri uporabi ovog prostora, posebno su razmotreni i opisani postupci planiranja, provedbe i nadzora utjecaja vojnih aktivnosti na okoliš.
Environmental protection during the implementation of military activities in the coastal area on the example of Cape Kamenjak (Croatia) is very important for the society and for the future of this area. It includes an overview and definition of contemporary challenges and strategies for protecting the important interests of the Republic of Croatia as a sovereign state on the example of a military model of the use and protection of a valuable micro-location on the Adriatic such as the protected area of Cape Kamenjak. The initial part of the chapter describes the flora and fauna on land and sea, and describes the responsibilities, measures and procedures of all users for environmental protection. The area of Cape Kamenjak is described in more detail, which has been declared a significant landscape due to its peculiarities. The conditions of use and protection of the space, the areas of application of special measures of planning and protection of the space are described, including the location and peculiarities with quantitative indicators, which are defined by the Spatial Plan of the County of Istria. In order to better understand the relationship of the military organization during usage of this area, the procedures of planning, implementation and monitoring of the impact of military activities on the environment were specially considered and described.
The paper presents digital image processing methods that, applied sequentially, enable detection and monitoring of flooded areas using satellite images obtained by Synthetic Aperture Radar (SAR) from ...Sentinel-1 satellite in the case study of floods in the Vrgorac region, during November and December 2020. The method is based on the scattering of a polarized radar wave on water surfaces. The paper comments on the advantages and disadvantages of using open resources and proposes the urgent accession of the Republic of Croatia to the Charter on Space.
U radu su prikazane metode digitalne obrade slike koje, slijedno primijenjene, omogućavaju detekciju i praćenje poplavljenih površina korištenjem satelitskih snimki dobivenih radarom sa sintetičkom ...aperturom (SAR) sa satelita Sentinel-1 na studiji slučaja poplave u vrgoračkom kraju, tijekom studenog i prosinca 2020. godine. Metoda se temelji na raspršenju polariziranog radarskog vala na vodenim površinama. U radu su komentirane prednosti i nedostatci korištenja otvorenih resursa te je predloženo žurno pristupanje Republike Hrvatske Povelji o svemiru i katastrofama.
The use of multispectral sensors, such as MSI, on the Sentinel-2 satellite for rapid as- sessment of the area and the burning degree after large forest fires utilises standard method of determining ...the Normalized Burn Ratio (NBR) before and after the fire, from which the dif- ference of the Normalized Burn Ratio (dNBR) is calculated. Applied to areas with sparse vege- tation, the standard method of NBR gives poor results. To cope with low vegetation areas, a so-called “relativizing dNBR” was introduced where an empirical expression divides the dif- ference of the NBRs in two channels by a quotient slightly greater than the pre-fire NBR.
In this paper, a forest fire near Vodice, Croatia, which occurred on July 14, 2022, and which grew into a catastrophic fire that left about 30 km2 of burnt area, was studied. As this is an area of Mediterranean vegetation, relatively sparse, instead of the relativization, an attempt was made to introduce a new formula for calculating the normalized ratio of burning, which includ- ed two differences in spectral radiances (instead of one). In addition to the standard difference in the near-infrared and short-wave infrared part of the spectrum, a difference between the near-infrared and the green visible part of the spectrum was used simultaneously. These new, bi-Normalized Burn Ratio, retain information about the spectral radiance in the green visible band and react to surfaces where at least a little vegetation cover remained after the fire, which ultimately gives lower burn categories, with the same burned area detected compared to the standard method.
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