Late‐Holocene wind‐field evolution at the southern Baltic coast as revealed by GPR data from the Mrzeżyno dunefield,NW Poland

All dunes within a dunefield usually show a similar response to the wind regime. However, in the late‐Holocene coastal dunefield in NW Poland the surface topography suggests that slipface orientation may vary significantly with distance from the coast, which is rarely reported in the literature. The dunefield was stabilized with forest in the mid‐19th century, preserving a unique record of atmospheric circulation in the South Baltic region at the end of the Little Ice Age. To elucidate the Holocene processes occurring along the study site a pseudo‐3D GPR data set was collected. Six grids of parallel GPR lines combined with 400 m of GPR profiles (2D) were collected across the dunefield and displayed using GOCAD for interpretation and geostatistical analysis. The geophysical data revealed that the larger dunes almost entirely consist of steeply laminated facies. Most importantly the pseudo‐3D data, supported by geostatistical estimates of strata dip directions, revealed the existence of three zones parallel to the coastline with the mean dip direction almost perpendicular to the coast in the northern coastal strip and almost parallel to it in the southern part. Spreads of the dip directions in pseudo‐3D GPR data sets recorded on the stoss slopes of dunes and crests suggested initial deposition on transverse dunes, which later were transformed into barchanoid dunes. This can probably be linked to changes in the wind regime, i.e. reduction in velocity of the northern and northwestern winds leading to reduced sediment supply from the coast. While the data provide a new interpretation of Holocene dunefield dynamics at this site, they also suggest that the minimum number of pseudo‐3D GPR grids required to establish general trends using geostatistical analysis should be at least 10, with even more data needed at larger, or more complex dunefields.     

Laboratory characterization of bent monocrystal wafers for Bragg X-ray spectroscopy

We describe our laboratory procedures for precise measurements of lattice surface profile, where Bragg reflection takes place, of bent monocrystal wafers. A comparison of X-ray spectrometer characteristics for perfect and real crystals is presented. The described procedures will be used to measure the properties of the crystals that will be used as the dispersive elements in the future solar X-ray spectrometers SolpeX and ChemiX.     

ChemiX: a Bragg crystal spectrometer for the <Emphasis Type="Italic">Interhelioprobe</Emphasis> interplanetary mission

Interhelioprobe (IHP), an analogue to the ESA Solar Orbiter, is the prospective Russian space solar observatory intended for in-situ and remote sensing investigations of the Sun and the inner heliosphere from a heliocentric orbit with the perihelion of about 60 solar radii. One of several instruments on board will be the Bragg crystal spectrometer ChemiX which will measure X-ray spectra from solar corona structures. Analysis of the spectra will allow the determination of the elemental composition of plasma in hot coronal sources like flares and active regions. ChemiX is under development at the Wroc?aw Solar Physics Division of the Polish Academy of Sciences Space Research Centre in collaboration with an international team (see the co-author list). This paper gives an overview of the ChemiX scientific goals and design preparatory to phase B of the instrument development.     

Application of the geomorphological instantaneous unit hydrograph theory to development of forecasting models in Poland

ABSTRACT

Geomorphological instantaneous unit hydrograph (GIUH) theory has been applied for the estimation of the parameters of two conceptual models: a linear cascade model and a Laurenson-type model. Conceptual models, especially the linear cascade model, are more convenient for operational forecasting than the original GIUH model. A single linear reservoir model is suggested, with limited storage to represent the subsurface flow component. Subsurface flow is significant in Polish mountainous river catchments. Preliminary results of applying the model to operational flood forecasting are described.     

Environmental and land use factors affecting phosphate hysteresis patterns of stream water during flood events (Carpathian Foothills,Poland)

Flood events play a substantial role in the circulation of catchment phosphate (PO₄^3?). The purpose of the research was to analyze the factors determining PO₄^3? hysteresis patterns (direction and width) during four types of floods: short and long rainfall floods and snowmelt floods on frozen and thawed soil. The research took place in small catchments (forested, agricultural, mixed‐use) in the Carpathian Foothills in Poland. Anticlockwise hysteresis was identified in the forested catchment during short and long rainfall floods. Under the same conditions, the clockwise direction was observed in the agricultural catchment. In the mixed‐use catchment, the direction of PO₄^3? hysteresis loops was various, driven by the share of water flowing from each part of the catchment. For snowmelt floods, the PO₄^3? hysteresis pattern was similar in all the streams studied (usually clockwise). The direction of PO₄^3? hysteresis loops depends on water circulation patterns, which are determined by the different influx times of particular runoff components. The stream recharge mechanism during a flood event is affected both by the factor initiating the event (precipitation, snowmelt) as well as by land use in the given catchment. Hysteresis loop width was determined by the pool of PO₄^3? in a given catchment during the time period immediately preceding a flood event as well as by the quantity of PO₄^3? flushed out of the soil. The greater a catchment's pool of PO₄^3? and the greater its ability to flush PO₄^3? out of the soil and into surface flow, the wider the hysteresis loops. Copyright © 2012 John Wiley & Sons, Ltd.     

Climate stability during the Eemian – new pollen evidence from the Nidzica site,northern Poland

Bińka, K., Nitychoruk, J. & Dzier?ek, J. 2010: Climate stability during the Eemian – new pollen evidence from the Nidzica site, northern Poland. Boreas, 10.1111/j.1502‐3885.2010.00179.x. ISSN 0300‐9483 Interglacial sediments at Nidzica, northern Poland were investigated by means of pollen and isotope analysis. These deposits accumulated in an extensive basin through most of the Eemian and Early Weichselian, practically without stratigraphic gaps. Continuous subsidence of the basin floor has resulted in the accumulation of a great thickness of lacustrine sediments, consisting mostly of calcareous gyttja. The course of pollen and isotope curves in the interglacial interval does not indicate the abrupt climatic shifts reported from some other continental climatic archives. Particularly important has been the reconstruction of the final stages of the Eemian, a potential analogue for future climatic change in the late Holocene. At Nidzica, this period is registered as a gradual modification of forest composition, devoid of any pulsations in which temperate forest is followed by terminal, boreal pine–birch communities.     

Hoarfrost and rime chemistry in Poland—An introductory analysis from meteorological perspective

Hoarfrost and rime analysis was based on the collection of samples between 2003 and 2006 from 8 sites, which represent both lowland (northern) and mountainous (southern) parts of Poland. On the other hand 4 of these sites belong to “urban” and 4 to “rural” category. pH, conductivity, SO₄²⁻, NO₃⁻, Cl⁻, H⁺, NH₄⁺, Ca²⁺, Mg²⁺, Na⁺, K⁺ have been determined in order to study the chemistry of hoarfrost and rime. Higher total inorganic ionic content (TIC) in hoarfrost and rime (2.46 meq·l⁻¹ and 1.23 meq·l⁻¹ respectively) was observed when compared with precipitation (0.37 meq·l⁻¹). Large variability of TIC and chemical composition of individual samples were typical at each of the measurement sites depending on emission patterns, atmospheric conditions and local terrain topography. Higher concentrations of both hoarfrost and rime occurred in southern (mountainous) rather than in northern (lowland) part of Poland which can be explained by worse pollutant dispersion conditions in the south. The surprisingly low hoarfrost concentrations in urban coastal stations in the area of the Bay of Gdansk were attributed to the cleaning effect of nocturnal breeze-type circulation, best pronounced in cool part of the year. Due to relatively high pollutant concentration and long duration, hoarfrost and rime are at least significant factors in environmental processes in different ecosystems in Poland.