Refractive index measurements of ammonia and hydrocarbon ices at 632.8 nm

Optical constants in a broad temperature and wavelength range are important input parameters in radiative transfer models used in studies of planetary atmospheres. In the laboratory, the refractive index values of ices at the HeNe laser wavelength (632.8 nm) are often used to monitor the growth rate and thickness of ice films. In this report we present laboratory measurements determining the refractive index at 632.8 nm of ammonia and hydrocarbon ices in the temperature range 80-100 K. Thin ice films are vapor-deposited on a cryogenically cooled mirror located inside a high-vacuum apparatus. The real component of the refractive index of these ice films is determined by a two-angle interferometric technique. Optical modeling calculations of the transmittance and reflectance through the thin ice films assist in the interpretation of the experimental results. We discuss our results and compare them with other measurements available in the literature. The results reported here are relevant to the spectroscopy of icy objects in the solar system; they are needed to perform laboratory characterization of ices, derive optical constants, and model spectra.     

Water reservoirs and the risk of accidental flood occurrence. Case study: Stanca–Costesti reservoir and the historical floods of the Prut river in the period July–August 2008, Romania

In the summer of 2008 the Prut river recorded a historical flow of 7140 m³/s at its entrance into Romania. This flow was the highest ever recorded of any Romanian river. The high value was generated by high amounts of rainfall recorded first on the territory of Ukraine and then in Romania. Unfortunately, there were some discrepancies between the data transmitted and intercepted from the Meteorology National Agency and Hydrology and Water Management National Agency. This is why the amount of precipitation which fell over the territory of Ukraine could not be monitored in time and punctually. Nor could the high flood wave moving rapidly from the upper basin to the lower basin. The high flow of the upper Prut caused the accumulation of an immense quantity of water in the Stanca–Costesti reservoir. Under the conditions of precipitation occurring in the lower river basin as well, the levels reached the flood quota and the reservoir reached the maximum accepted capacity, with 0·1% insurance. The release of supplementary water quantities from the reservoir would have produced catastrophic floods downstream. Keeping the water in the reservoir could have broken it and the flooding, through backwater eddies, or the riverbank settlements. In such a case, it would have produced the greatest tragedy in the hydrological history of Europe. The most significant damage was produced upstream of the barrage, next to the localities of Radauti Prut and Baranca–Hudesti, as well as in the area of the reservoir, as a result of the phenomenon known as ‘remuu’, or backwater eddies. The floods of the Prut river occurred between the end of July and the end of August. Copyright © 2011 John Wiley & Sons, Ltd.     

An inter‐basin backwater overflow (the Buhai Brook and the Ezer reservoir on the Jijia River,Romania)

During the last few years, the north‐western part of Romania has been affected by catastrophic floods with most of the watercourses reaching their highest recorded discharges. This study reports the generation of a numerical terrain model and the simulation of a backwater phenomenon at elevation steps according to the volume of water accumulated at the confluence of the Buhai Brook with the Jijia River. The hydrological data are complemented by rainfall data and the careful recording of the flood behaviour during the entire period of its development. The main aim of the study is to identify the causes of the backwater phenomenon and to highlight the material damage inflicted on the town of Dorohoi. At the same time, the study uses cartographic model that was developed to establish which areas are at risk of flooding at various levels of probability. The catastrophic flood began on the Buhai Brook, a slow‐flowing stream that drains the areas to the west of the town of Dorohoi and discharged into the upstream sector of the Jijia confluence. The flood caused two types of backwater waves: one behind the bridges and the houses built on the floodplain and a second that followed the course of the main stem (Jijia) upstream from the confluence, flooding the Ezer Lake, which was created specifically to attenuate such floods. The spillway backwater phenomenon was inter‐basin as it did not occur in a single hydrographic basin. The causes of the catastrophic flash flood and of the inter‐basin backwater overflow are natural but also reflect anthropogenic influence. After the lake filled, the discharge into the Jijia was controlled and the flooding downstream was thus greatly diminished. Though fortuitous, the backwater flooding was important in mitigating the impact of the flood wave from the Jijia River. Copyright © 2013 John Wiley & Sons, Ltd.     

Causes and effects of the catastrophic flooding on the Siret River (Romania) in July–August 2008

Natural Hazards - As a result of the massive deforestation and windfalling in Romania last year, catastrophic floods frequently occur with historic high-water marks only to be registered every 500...     

The effects of the July 2005 catastrophic inundations in the Siret River��s Lower Watershed, Romania

The Siret River originates from the Wooded Carpathians (Ukraine) and has a length of 559 km on the Romanian territory. The upper river course is set on the Ukrainian territory, the middle course flows through the Suceava Tableland, and then the limit between the Moldavian Subcarpathians and the Bârlad Tableland, followed by the lower course crosses the Inferior Siret Plain. The hydrographical network includes 1,013 water tributaries (representing the richest river from this point of view in Romania) and has a length of 15,157 km, which represents 19.2% of the total length of the Romanian river network. This materializes in a density of 0.35 km/km², compared to 0.33 km/km² which is the average for Romania. The Siret River has the greatest watershed area, with a total surface of 42,890 km², which represents 18.1% of the Romanian territory. Its discharge is the highest of all internal rivers of Romania, with an average discharge of 210 m³/s at the river mouth, and this is caused by the fact that most of the tributaries come from mountainous sectors, namely the Eastern Carpathians. In the summer of 2005, the most powerful floods ever occurred in the Siret River watershed with significant negative effects on the country??s economy. Considering the multiannual average discharge of 210 m³/s, the maximum discharge recorded on July 16, 2005, was of 4,650 m³/s at Lungoci. The main cause of these events is the deforestation of the small watersheds located in the mountainous sector of the counties of Vrancea, Bacau and Neamt. The total surface affected by floods was of 58,323.936 hectares, of which: 34,142.349 ha (58.54%) arable land, 6,697.486 ha (11.48%) orchards and wine-growing plantations, 1,863.698 ha (3.20%) built areas, 2,866.313 ha (4.91%), forests 4,915.985 ha (8.43%), waters 2,081.047 ha (3.57%), and unproductive land 5,757.058 ha (9.87%). Besides the material losses (over 10,000 houses completely destroyed), 24 human deaths were recorded together with the loss of thousands of domestic animals, whose overall value exceeded two million Euros. The estimation of the extent of the flooding and its impact in the Siret River watershed has been performed using LANDSAT TM 2003 satellite images and the FAO-LCCS classification methodology, in the ASR-CRUTA remote sensing laboratory, with the images offered after activating the International CHARTER (Call ID-98).