hainan coherent scatter phased array radar hcopar system design and ionospheric irregularity observations the hainan coherent scatter phased array radar hcopar is one of the most important radio systems of the chinese meridian space weather monitoring project meridian project the radar is located at fuke station 19 5 n 109 1 e dip latitude 8 1 n hainan island china to observe the field aligned irregularities in ionospheric e and f regions it is operated with a peak power of 54 kw and uses the barker codes for good sensitivity its antenna array is composed of 18 times 4 five element yagi antennas and is used for both transmitting and receiving the yagi antennas are arranged in a rectangular grid 100 m long and 20 m wide covering an area of 2000 m2 this antenna arrangement forms seven radar beams from 22 5 to 22 5 in azimuth with an angle step of 7 5 the central beam points to due geographic north a brief description of the radar system data processing and signal characteristics is also provided the intensity doppler velocities and spectral widths of the quasi periodic echoes measured in the nighttime of june 23 2013 are presented as typical data of type ii irregularities in the e region the data recorded by the hcopar in the fan beam mode on september 15 2013 are displayed as the typical f region plasma bubbles

on post midnight field aligned irregularities observed with a 30 8 mhz radar at a low latitude comparison withf layer altitude near the geomagnetic equator 1 we investigated the relationship between post midnightf region field aligned irregularities fais andf layer altitude by analyzing data of a 30 8 mhz radar installed 5at kototabang indonesia 0 2 s 100 3 e geomagnetic latitude 10 4 s and an ionosonde installed at chumphon thailand 10 7 n 99 4 e geomagnetic latitude 3 3 n chumphon is located near the geomagnetic equator on approximately the same meridian as kototabang case studies show that the altitude of thef layer rose at chumphon a half hour before the post midnight fais appeared at kototabang the doppler velocity of thee region fais observed simultaneously by the 30 8 mhz radar was downward indicating that thef layer uplift was not caused by the electric field we also investigated seasonal variations of the post midnight fai occurrence and thef layer altitude both the post midnight fais and the uplift of thef layer were frequently seen around midnight between may and august the seasonal variation of the midnightf layer uplift around the geomagnetic equator coincided with that of the post midnight fai occurrence at kototabang these results suggest that the uplift of thef layer would play an important role in the generation of post midnight fais we evaluated the linear growth rate of the rayleigh taylor instability based on the altitude of thef layer observed at chumphon the result shows that the uplift of thef layer can enhance the growth rate because gravity driven eastward electric current increases therefore we interpret that the observed fais were accompanied by plasma bubble the growth rate of which was reinforced by the upliftedf layer

low latitude daytime f region irregularities observed in two geomagnetically quiet days by the hainan coherent scatter phased array radar hcopar hainan coherent scatter phased array radar hcopar located at low latitude of china has recorded the extremely rare daytime f region irregularities at noon of 22 july 2013 and 23 may 2016 the two field aligned irregularities fais appeared in the topside f2 layer and presented small doppler velocities and narrow spectral widths the fan sector maps show that the fais moved northward with almost no zonal speed the irregularities emerged in the geomagnetically quiet condition and were irrelevant to the storm induced eastward electric field as other daytime cases more than two hours after the emergency of the daytime irregularities over hainan the shaoyang digisonde situated 870 km north to the hcopar recorded the spread f in ionospheric f1 layer according to the echo altitudes the spread f may connect the daytime bubbles via magnetic field line the strong photo ionization after sunrise made it difficult to generate the plasma bubbles in the sunlit ionosphere consequently the two midday fais over hainan may drift along the magnetic field lines from higher altitudes in the south and are most likely the remnant of previous night s bubbles

dual phase mass balance modeling of small mineral particle losses from sedimentary rock derived soils abstract losses of small mineral particles can be a significant physical process that affects the elemental composition of soils derived from sedimentary rocks shales in particular contain abundant clay sized minerals that can be mobilized by simple disaggregation and solutional weathering is limited because the parent rock is composed primarily of recalcitrant minerals previously subjected to continental weathering here the dual phase mass balance model is employed to quantify losses of small mineral particles as water dispersible colloids wdcs from three previously studied soil profiles along a hill slope at the susquehanna shale hills critical zone observatory ssho wdcs were isolated from soil in the laboratory to determine their mineralogical and elemental compositions clay minerals dominated wdcs including illite vermiculite and chlorite inherited from the parent shale along with neoformed kaolinite quartz present in bulk soil was generally excluded from wdcs elements of low solubility and or bound in recalcitrant forms like rb in illite were employed in tracer ratios in the dual phase model aluminum ga and rb were enriched in wdcs and zr and hf were partially excluded six different combinations of elements into tracer ratios al zr ga zr rb zr al hf ga hf rb hf each yielded similar model results mass losses of wdcs were large ranging from 68 7 to 15 5 relative to soil parent material in different parts of the profiles mass losses via solution were smaller ranging from 7 2 to a gain of 6 1 in part of one profile losses of wdcs account for 90 of total mass loss surpassing chemical dissolution and therefore dominate the weathering portion of denudation at ssho zirconium concentrations were 97 158 ppm in the generally 1 m wdcs suggesting colloidal zr bearing phases model quantified losses of zr via wdcs were large with a median loss of 41 relative to parent material such losses indicate systematic underestimates of weathering by traditional mass balance that uses zr as an index element losses of ca mg and k via wdcs exceeded losses via solution countering assumptions of base cation losses primarily via mineral dissolution the results illustrate a geochemical fingerprint of physical weathering and the ability of the dual phase model to quantify that weathering process

clay coatings formation in tepetates from texcoco mexico abstract tepetates are common in the mexican highlands and are classified as fragipan duripan pedosediments or saprolite a common feature is the abundance of clay coatings three pedons with red tepetate and grey tepetate were selected at different altitudes and slopes in a small watershed in texcoco mexico physical chemical mineralogical and micromorphological analyses were carried out in soil tepetate and separated clay coatings clay illuviation and neoformation indexes were calculated using micromorphometric techniques red tepetate is composed of basic volcanic glass dust andesitic vitric tuff and has a high clay neoformation and illuviation index in contrast grey tepetate is composed of acid volcanic glass acid vitric tuff and only clay neoformation takes place leading to the formation of a clayey soil although all the tepetates were subject to pedogenesis the intensity and variation of the processes increases on the lower slope and different diagnostic horizons are formed due to tepetate erosion the laterally running waters containing suspensions of particles and soluble silica were deposited or precipitated in sediments or tepetates on the lower slopes giving rise to compound coatings these processes must be older than 20 000 years tepetates from texcoco present several variants which were recognised since pre hispanic times

low latitude ionospheric density irregularities and associated scintillations investigated by combining cosmic ro and ground based global positioning system observations over a solar active period

daytime e region field aligned irregularities observed during a solar eclipse the driving mechanism of the midlatitude field aligned irregularities fais has been in dispute for many years the experimental observations were carried out during the solar eclipse of 22 july 2009 in wuhan china to study the possibility of the wave driven irregularities a high frequency coherent scatter radar was used to detect the e region irregularities an ionosonde was applied to record the trace of gravity waves in ionosphere the e region fais occurred at the end of the solar eclipse with fluctuant doppler at the same time the oscillations on the fes maximum reflecting frequency of es curve and in the doppler velocity of the echoes from the es layer were also recorded the data analysis and comparison show that the gravity waves and the fais occurred at the same time with the in phase variations in amplitude and phase thus the solar eclipse and the gravity waves may play important roles in the occurrence of the irregularities a schematic diagram of one period gravity wave is used to explain the possible gravity wave driven mechanism and the doppler fluctuation in the irregularities the daytime fai in midlatitude is a rare phenomenon even in the condition of solar eclipse there are only four cases of the e region fais observed during a solar eclipse including our observations the unique feature of our observations is the synchronized oscillations in the irregularities and in the es layer which will help address the outstanding question of the source of the midlatitude e region fais

the diurnal hysteresis of snow albedo l hysteresis diurne de l albedo de la neige est principalement attribuee a la forme de la surface sastrougi

altitude extended equatorial spread f observed near sunrise terminator over indonesia 1 spatial structure of a post sunrise backscatter plume associated with a plasma bubble has been observed for the first time with the 47 mhz equatorial atmosphere radar ear in west sumatra indonesia 0 20 s 100 32 e dip latitude 10 36 n this plume is likely associated with a geomagnetic storm it extended from what appears to be the base of the f layer into the topside ionosphere and differed from all plumes previously observed it was also extended in longitude i e in the east west direction and appeared to involve two spatially separated regions the plume was first observed around sunrise close to 200 250 km altitude but at a time when the e region was not yet sunlit spatial maps of the line of sight doppler velocity show that there was upward development and westward drift of backscatter regions indicative of daytime drift conditions the observations remain puzzling because the plume continued for approximately two hours after e region sunrise

measuring glacier surface roughness using plot scale close range digital photogrammetry glacier roughness at sub metre scales is an important control on the ice surface energy balance and has implications for scattering energy measured by remote sensing instruments ice surface roughness is dynamic as a consequence of spatial and temporal variation in ablation to date studies relying on singular and or spatially discrete two dimensional profiles to describe ice surface roughness have failed to resolve common patterns or causes of variation in glacier surface morphology here we demonstrate the potential of close range digital photogrammetry as a rapid and cost effective method to retrieve three dimensional data detailing plot scale supraglacial topography the photogrammetric approach here employed a calibrated consumer grade 5 mpix digital camera repeatedly imaging a plot scale 25 m2 ice surface area on midtre lovenbreen svalbard from stereo pair images digital surface models dsms with sub centimetre horizontal resolution and 3 mm vertical precision were achieved at plot scales 4 m2 extraction of roughness metrics including estimates of aerodynamic roughness length z 0 was readily achievable and temporal variations in the glacier surface topography were captured close range photogrammetry with appropriate camera calibration and image acquisition geometry is shown to be a robust method to record sub centimetre variations in ablating ice topography while the dsm plot area may be limited through use of stereo pair images and issues of obliquity emerging photogrammetric packages are likely to overcome such limitations

on the albedo of snow in antarctica a contribution to i a g o mesures de l albedo de la couverture neigeuse pendant l ete austral 1985 86 dans la zone de neige seche de terre adelie en antarctique

experimental approach of lessivage quantification and mechanisms abstract lessivage also called argilluviation consists of a substantial vertical transfer of particles less than 2 m from a superficial departure horizon to a deeper horizon this process is common in many soil types and responsible for the development of a textural differentiation in soil profiles in the subsurface however the mechanisms of lessivage are still poorly understood and to our knowledge lessivage has rarely been quantified we propose here two original experiments of in vitro pedogenesis on soil columns to analyse the mechanisms acting in eluviation and illuviation the two phases of lessivage and to quantify these two phases in terms of particle export and fixation we paid special attention to the experimental conditions so that the conditions were favourable for lessivage and as close as possible to field conditions the eluviation experiment showed that the release of particles was not the determining process for lessivage we also showed that the smectite selectivity of eluviation was not continuous over time both physical and chemical processes were identified as acting on both eluviation and illuviation concerning illuviation experiments showed that from 25 to 90 of the eluviated particles were retained in the deeper horizon although large to our knowledge this range represents the first quantification of illuviation

how robust are in situ observations for validating satellite derived albedo over the dark zone of the greenland ice sheet abstract calibration and validation of satellite derived ice sheet albedo data require high quality in situ measurements commonly acquired by up and down facing pyranometers mounted on automated weather stations aws however direct comparison between ground and satellite derived albedo can only be justified when the measured surface is homogeneous at the length scale of both satellite pixel and in situ footprint here we use digital imagery acquired by an unmanned aerial vehicle to evaluate point to pixel albedo comparisons across the western ablating margin of the greenland ice sheet our results reveal that in situ measurements overestimate albedo by up to 0 10 at the end of the melt season because the ground footprints of aws mounted pyranometers are insufficient to capture the spatial heterogeneity of the ice surface as it progressively ablates and darkens statistical analysis of 21 aws across the entire greenland ice sheet reveals that almost half suffer from this bias including some aws located within the wet snow zone

morphological features related to agriculture and faunal activity in three loess derived soils in france abstract three soils developed in late weichselian loess in france were studied to document morphological features related to agricultural and faunal activities one soil had been in deciduous forest at least 100 years one had been in permanent grass pasture for at least 25 years and one had been annually cultivated for at least 50 years the investigation included field descriptions chemical and physical characterizations and thin section studies the surface horizon ap of the cultivated soil was thicker than surface horizons of the forest and pasture soils probably because of deep tillage to about 35 cm depth another probable effect of deep tillage of the cultivated soil was to mix horizons destroying evidence of an eluvial zone near the soil surface soil in both forest and pasture exhibited numerous features related to faunal activity in both surface and subsurface horizons including large channels abundant fecal pellets channel infillings and organic intercalations these features were correlated with rather weak expression of illuvial clay accumulations in pores of the b horizons although bulk characterization indicated the presence of argillic horizons in contrast b horizons of the cultivated soil had somewhat lesser macroporosity and fewer fecal pellets infillings and intercalations but strongly expressed illuvial coatings with the assumption that the three soils had similar morphologies before cultivation the observations suggest that greater faunal activity in the soils in forest and pasture led to more significant disruption of illuvial pedological features than in the soil under cultivation

luvisols or cambisols micromorphological study of soil truncation in young morainic landscapes case study brodnica and chelmno lake districts north poland abstract eight soil profiles in brodnica lake district and chelmno lake district were described and sampled the profiles were divided into four pairs study areas dissimilar in lithology relief or land use each pair of profile contained soil located on the crest or upper slope exposed to erosion and back slope slightly exposed to erosion positions the relief of this area is inherited from the last vistulian glaciation and represents mostly flat and hummocky moraine plateau landscapes all investigated pedons have a b horizon five profiles have vertical contrasting texture and contain a significantly developed eluvial zone a and e horizons above b horizon in three cases pedons have a b c horizon sequence to date numerous studies have shown that the soils with a b c profiles developed on moraine tills should be treated as cambisols on existing soil agricultural maps these soils are also marked as cambisols the b horizons are enriched in the clay fraction and contain low amount of carbonates in comparison with the parent material all these criteria can be used to distinguish a cambic horizon but analysis of thin sections revealed the presence of significant amounts of clay and silt illuvial features the illuvial pedofeatures resulted in these horizons being classified as argic horizons bt these soils cannot be classified as cambisols which are characterized by absence of appreciable amounts of illuvial silt and clay instead the a b c profile forms represent truncated luvisols in which the material from eluvial horizons was entirely removed the soils described in this study occur in areas where soil erosion is common the upper part of slopes and crests in arable areas the illuvial origin of b horizons in truncated pedons a b c was also confirmed by the presence of eluvial horizons in nearby soils on the back slope position slightly or non exposed to erosion the results showed that accelerated erosion had a significant role in development of soil cover in agriculture moraine landscapes of brodnica and chelmno lake districts the micromorphological analysis confirmed that the loamy soils with the a b c profile developed on ground moraine tills should be classified as truncated eroded luvisols the b horizons of these soils have significant accumulation of clay and silt features the illuvial microforms are the relic feature of eluviation illuviation lessivage process the material from the eluvial horizons of luvisols was entirely removed this study is important to understand the influence of soil erosion processes on soil cover development in young glacial regions further investigations concerning formation and characteristic of a b c soils and appropriate classification of described pedons are very important for understanding the impact of accelerated erosion in young glacial landscapes

visible and near infrared reflectivity during the ablation period on peyto glacier alberta canada models for calculating glacier mass balance are sensitive to surface reflectivity variation fieldwork carried out on peyto glacier alberta canada contributes to the data set available for ice reflectivity parameterization in such models hemispherical reflectivity in the visible and near infrared parts of the solar spectrum was obtained for rock snow and three contrasting glacier surfaces to examine temporal and spatial variations glacier ice near infrared reflectivity displays only minor spatial variation 0 12 0 17 in comparison with the visible range 0 23 0 40 the latter being influenced primarily by surface impurity content surface roughness is of minor importance compared with impurities temporal variation of reflectivity was weak at all glacier ice and rock locations slight variations observed were due to changes in either solar zenith angle or cloud amount snow reflectivity displayed pronounced diurnal asymmetry and a larger response to cloud cover the minimal temporal variation in glacier ice reflectivity simplifies its parameterization this behaviour is additionally useful for satellite based measurements of the reflectivity field on larger glaciers as images obtained within a 6 h window centred on solar noon are likely to yield values which are within 2 3 of daily mean values

hydromorphic and clay related processes in soils from the llanos de moxos northern bolivia abstract the llanos de moxos is one of the largest wetlands in the world more than 100 000 km2 due to seasonal floods the soil parent materials are fine quaternary sediments brought by tributaries of the amazon river forests cover some areas although the dominant vegetation is a pastured savannah and backswamps at present the main land use is a very extensive rangeland and slash and burn agriculture in minor areas we have studied 15 profiles from several sample areas between trinidad and san ignacio field and laboratory studies have been carried out in order to elucidate the soil forming processes taking place and to gain basic knowledge for a sustainable land management coarser soils are located near the present river system or in former riverbank areas often under forest textures here are loam or silty loam silty clay loam being dominant finer soils may have up to 85 clay and are usually under savannah cover illite is the dominant clay mineral in all soils followed by smectite and kaolinite vermiculite is absent quartz is present in a very significant amount in the clay fraction of all studied soils goethite and lepidocrocite are present in all soils lepidocrocite being a good indicator of poor drainage conditions soils are mainly acid but there are soils with calcium carbonate accumulation in the subsoil or even saline soils salitrales soils are flooded for a significant period 3 6 months and bypass flow is very active hydromorphic processes are always present and morphologies include hard and soft iron manganese concretions with diffuse boundaries within peds impregnative fe coatings and fe depletion hypocoatings along pore walls the micromorphological study shows different degrees of hydromorphism some of them associated to the present pore system and some with a palaeo character often disturbed by active slickensides microsparite nodules are also present in some low lying soils the soils present several morphological features related to the mobility of the fine fraction that can be related to drainage conditions as recent clay coatings clay and silt infillings and coatings and clay depleted hypocoatings the most clayey soils show striated b fabrics and frequent slickensides and some others point to ferrolysis as iron depleted hypocoatings and low crystallinity clay coatings along pores although this is not supported by mineralogical data a moderate cation supply probably prevents strong acidification

spatial and temporal variations in albedo on storglaciaren sweden extensive albedo data from storglaciaren sweden during nine summers are analyzed focusing on the effect of surface slope on measurements and on the influence of clouds on albedo of both snow and ice surfaces on clear sky days albedo continuously dropped throughout the day by 0 3 when derived from measurements in a horizontal plane over the slightly sloping surface when we correct for the tilt effect over frozen surfaces the apparent decrease in albedo largely disappeared while over melting surfaces it became significantly less pronounced this emphasizes the need to correct horizontally measured data for slope when they are used for example as ground truth for satellite derived albedo or in high resolution glacier melt runoff models albedo varied by 0 1 due to cloud fluctuations to quantify cloud effects albedo changes between successive half hourly and daily data were regressed against corresponding changes in cloudiness expressed by the ratio of global radiation to top of atmosphere solar radiation the resulting relationship over snow explains 66 of oberved albedo changes using hourly and 4 using daily time steps over ice the corresponding values arc 28 and 0 hence cloudiness is a dominating factor in determining short term variability of albedo over snow whereas over ice the observed large day to day variability 20 is mainly attributed to changes in the physical characteristics of the weathering crust results suggest that cloud effects should be incorporated into models treating snow and ice surfaces separately

development of texture contrast soils by a combination of bioturbation and translocation abstract soils and weathering profiles in a wide variety of parent materials and environmental settings exhibit coarse over fine vertical textural contrasts where these cannot be attributed to inherited texture contrasts or erosion deposition the most common explanations are based on translocation eluviation illuviation which removes clays from surface layers and deposits them in the subsoil or bioturbation where preferentially fine material is delivered to the surface by organisms from whence erosional winnowing creates a coarse surface layer in some soils of the lower coastal plain of north carolina u s a neither explanation is sufficient to explain the observed texture contrasts a heuristic model based on a combination of translocation of fine material from surface to subsoil and bioturbation driven delivery and recycling of material to the surface can explain the observed vertical textural contrasts the key elements in the model are coastal plain sediments which include some fine material eluviation illuviation by percolating water delivery of additional fine and mixed grain size material to surface by bioturbation making it available for translocation concentration of fine material originally scattered throughout the parent material in a b horizon and maintenance of vertical moisture fluxes by bioturbation the model is supported by morphological evidence of the key mechanisms argillic horizons that are finer than both the surface layers and underlying parent material evidence that argillic horizon formation is not limited by the rate of clay synthesis and the absence of texture contrasts in nearby soils formed from dune sands which lack fines

mass balance gradients and climatic change it is generally assumed that the mass balance gradient on glaciers is more or less conserved under climatic change in studies of the dynamic response of glaciers to climatic change one of the following assumptions is normally made i the mass balance perturbation is independent of altitude or ii the mass balance profile does not change it simply shifts up and down observational evidence for such an approach is not convincing on some glaciers the inter annual changes in mass balance seem to be independent of altitude on others not at all moreover it is questionable whether inter annual variation can be projected on different climatic states to see what a physical approach might contribute we developed an altitude dependent mass balance model it is based on the energy balance of the ice snow surface where precipitation is included in a parameterized form and numerical integrations are done through an entire balance year with a 30 min time step atmospheric temperature snowfall and atmospheric transmissivity for solar radiation are all dependent on altitude so a mass balance profile can be calculated slope and exposure of the ice snow surface are taken into account and the effects of these parameters studied in general the calculations were done for 100 m elevation intervals climatological data from the sonnblick observatory austria 3106 m a s l and from vent 2000 m a s l oetztal alps austria served as input for a number of runs simulation of the mass balance profiles for hinterseisferner north easterly exposure and kesselwandferner southeasterly exposure yields reasonable results the larger balance gradient on kesselwandferner is produced by the model so exposure appears to be an important factor here sensitivity of mass balance profiles to shading effects different slope and exposure are systematically studied another section deals with the sensitivity to climatic change perturbations of air temperature cloudiness albedo and precipitation are imposed to see their effects on the mass balance profiles the results clearly show that in general mass balance perturbations depend strongly on altitude they generally increase down glacier and are not always symmetric about the reference state for typical climatic conditions in the alps we found that a 1 k temperature change leads to a change in equilibrium line altitude of 130 m three factors contribute to this large value turbulent heat flux longwave radiation from the atmosphere and fraction of precipitation falling as snow here the albedo feed back increases the sensitivity in a significant way

temporal and spatial variations in spectral reflectance and characteristics of surface dust on gulkana glacier alaska range spectral reflectances in the visible to near infrared wavelength range 350 1050 nm were measured on the surface of gulkana glacier alaska range alaska usa at six different elevations from may to september 2001 the measurements showed variable spectral reflectances on the glacier surface and the spectra changed over time and elevation the spectra in may were those of a typical wet snow surface the reflectance ranged approximately from 0 4 to 0 8 and generally decreased as the wavelength increased as snowmelt proceeded the reflectance gradually fell and specific absorptions appeared in the spectrum at wavelength ranges of 400 600 and 670 680 nm corresponding to a red snow surface due to snow algal bloom as the ice surface was exposed the spectrum finally shifted to a lower 0 1 0 4 and flat reflectance curve typical of an ice surface contaminated with dust analyses of the dust on the glacier surface showed that its quantity and characteristics changed spatially and seasonally and were correlated with spectral albedo the results showed that the temporal and spatial variations in spectral reflectance on this glacier are due not only to physical properties of the glacier surface but also to biogenic materials on the surface e g red colored snow algal cells and cryoconite

rapid quantification of cryoconite granule geometry and in situ supraglacial extents using examples from svalbard and greenland supraglacial dust cryoconite is an important but poorly understood component of the glacial system there is a lack of primary data on cryoconite form extent and dynamics here we present a suite of rapid low cost methodologies for quantification of granule geometry and supraglacial cryoconite coverage using image data captured by commercially available digital cameras we develop robust transferable protocols for analysis of 1 cryoconite granule geometry major axis feret diameter circularity 2 centimetre metre scale supraglacial extent m2 cryoconite m 2 surface and 3 temporal change in supraglacial extent at hourly intervals over several days image processing methodologies were developed using the public domain software imagej manual supervised controls were used to estimate sources of error and measurements then automated using simple scripting tools macros fully automated processing successfully identified 90 of a sample of isolated granules ranging between 2 5 and 39 2 mm with uncertainties of 20 particle sphericity inferred from circularity decreased as particle size increased supraglacial cryoconite extent was obtained with a mean uncertainty of 37 and 22 for data from field sites in greenland and svalbard respectively these methods will facilitate acquisition and analysis of datasets for cryoconite across a range of spatial scales supporting research into cryoconite impacts on supraglacial hydrological connections nutrient and carbon cycling and initiation of primary succession in deglaciating environments

geochemistry δ13c δ15n 13c nmr and residence times 14c and osl of soil organic matter from red brown earths of south australia implications for soil genesis abstract soil forming processes important to the development of red brown earths duplex soils in southeastern australia have been investigated by a combination of techniques including isotopic 13c 15n 14c spectroscopic 13c nmr mir optically stimulated luminescence dating osl and phytolith analyses a distinct increase in clay content corresponding changes in the abundance of major elements as well as changes in organic chemistry 13c nmr stable isotope trends 13c 15n and phytolith abundance are apparent in the transition from the very sandy a horizon to the clayey b horizon in three soil profiles from the coonawarra padthaway region of south australia these structural and chemical changes between the a and the b horizons are associated with an abrupt increase in both 14c bulk soil organic matter and osl burial ages of individual quartz grains while previous interpretations have promoted the formation of duplex red brown earths as due to clay illuviation we propose a two stage soil formation which may be related to paleoclimatic changes during and after the last glacial maximum our data suggest that a major part of the a horizon was aeolian derived and was deposited over the last 10 000 years whereas much of the b horizon although originally aeolian has been extensively modified over much longer periods of time tens of thousands of years these results indicate the influence of different substrates sandy versus clayey process and time for formation as well as paleoclimatic history on the physical properties of the soil and the chemical characteristics of the organic matter within the soil profile

spectral albedos of sea ice and incident solar irradiance in the southern beaufort sea spectral albedos and incident spectral irradiances have been measured over the wavelength range 400 to 2400 nm on the sea ice near the naval arctic research laboratory narl at pt barrow alaska the observation interval extended from mid may when the ice was still relatively cold until mid june when summer melting was fully established the temporal dependence of albedo for the available surface types was obtained over this time interval showing a general decrease from snow and snow covered ice to blue ice and melt ponds data were also obtained for glacier ice on the athabasca glacier for melting lake ice and for certain other nonice surfaces in the vicinity of narl snow and ice albedos are characteristically highest at visible wavelengths decreasing strongly in the infrared because of the increase in absorption by ice and water local maxima in the spectra correspond to minima in the ice and water absorption variations in albedo are due primarily to differences in the vapor bubble density crystal structure and free water content of the upper layers of the ice incident spectral shortwave radiation was measured as a function of cloudiness and the optical thickness of arctic clouds is significantly less than the thickest clouds at lower latitudes the decrease of the infrared component relatiave to the visible portion of the irradiance with increasing cloud cover is determined this can give rise to an increase in wavelength integrated albedos of as much as 15 using the present data a graphical method is outlined by which visible near infrared satellite imagery can be used to distinguish among melt ponds open leads and other spring and summer sea ice surface types

modelling soil genesis in calcareous loess abstract the soilgen1 model was developed to simulate soil development in calcareous loess at holocene 15 000 bp present temporal extent we used the leachc model as a core and added process formulations to describe the effect of vegetation and soil macrofauna on various soil properties a limited calibration was done on the calcite solubility constant by comparing decarbonization rates in various leaching climates with values predicted by the metamodel of egli and fitze egli m and fitze p 2001 quantitative aspects of carbonate leaching of soils with differing ages and climates catena 46 35 62 soil profiles of c and ph after 15 000 years compared well with measurements in a belgian loess profile that was never under agriculture taking the composition of the c horizon as uniform parent material scenarios with and without agriculture with varying degrees of bioturbation and for documented holocene climatic and vegetation evolutions in belgium and hungary were simulated and compared results show a clear effect of bioturbation on soil development especially in the continental climate evolution of hungary indicators for the possible occurrence of clay migration and disturbance of lateglacial morphology were calculated and these also show the importance of bioturbation

mid latitude ionospheric irregularities persisting into late morning during the magnetic storm on 19 march 2001 1 post sunrise intense ionospheric irregularities at low to mid latitudes are reported for the first time a method based on spaced receiver technique is proposed to estimate the apparent drift velocity of the irregularities by using the correlation of the slant total electron content tec from 3 gps receivers the irregularities were detected at 23 45 n by the gps earth observation network geonet of japan from 0455 lt to 1051 lt on 21 march 2001 during the recovery phase of the magnetic storm at the corresponding time spread f was observed with 3 ionosondes located meridionally at okinawa 127 8 e 26 3 n 20 7 n magnetic latitude kokubunji 139 5 e 35 7 n 30 0 n magnetic latitude and wakkanai 141 7 e 45 4 n 40 5 n magnetic latitude while an intense negative ionospheric storm was processing and propagating from mid to lower latitudes the irregularities were seen as plasma bubbles by the defense meteorological satellite program dmsp in situ measurements westward drift with the speed of 100 m s was estimated by spaced receivers from geonet and confirmed by dmsp during the evolution of the irregularities the plasma bubbles at mid latitude sustained 1 5 hour after sunrise and at the lower latitudes they survived more than 4 hours after sunrise the observations suggested that the irregularities were generated by an eastward electric field associated with the disturbance dynamo and the long time existence of the irregularities after sunrise seemed to be related to the daytime intense negative ionospheric storm on 21 march

clay illuviation and calcium carbonate accumulation along a precipitation gradient in kansas one of the significant features of loess derived soils in kansas is the occurrence of clay rich subsurface horizons above a layer enriched with pedogenic carbonates in order to examine the extent of clay increase and pedogenic carbonate enrichment in a precipitation gradient ten soil profiles from three different precipitation regions were studied using micromorphological and mineralogical techniques the precipitation gradient was divided into three groups 400 550 mm 550 750 mm and 750 1100 mm regions the objectives were to 1 understand the cause of clay orientation in clay rich horizons 2 investigate the reasons for the clay increase and 3 observe the interaction of clay and pedogenic carbonate accumulation features along a precipitation gradient in kansas although clay films were identified in the field for soils in the 400 550 mm regions illuvial clay films were not observed in thin section analysis the clay accumulations mostly occurred as grain coatings the rest of the clay accumulations observed were very thin striated and mostly associated with voids the argillic horizons had a granostriated b fabric which indicates stress orientation of micromass caused by high shrink swell activity thick and continuous illuvial coatings were observed in the buried horizons of paleosols in the other two regions where precipitation exceeds 550 mm illuvial clay coatings with strong orientation were observed along with thin and striated stress oriented clay both types of clay orientations exceeded 1 of the cross sectional area for the thin section although illuvial clay features and pedogenic carbonates were observed in all soils at approximately the same depth complete obliteration of clay coatings was not observed in these horizons in situ weathering of biotite was one of the reasons for the clay increase in all soil profiles in all soils studied the clay increase and cause of clay orientation cannot be attributed to a single genetic process or event both illuviation and shrink swell activity were involved in the orientation of clay although orientation of clay and pedogenic carbonates were observed in all soils at approximately the same depth the decomposition of clay coatings was not observed in these horizons