radiative transfer modeling of near infrared reflectance of lunar highland and mare soils 1 with near infrared hyperspectral data sets returned from kaguya selene and chandrayaan 1 s moon mineralogic mapper m3 accurate evaluation and interpretation of lunar data sets with higher spectral resolution has never been more critical here we test a new radiative transfer spectral modeling algorithm to determine composition from hyperspectral reflectance spectra of lunar soils data for 19 lunar mare and highland soil samples previously characterized by the lunar soil characterization consortium are used for validation spectral fits are made using a goodness of fit metric considering spectral shape spectral contrast spectral slope and iron abundance high precision fits are achieved for nearly every soil with this algorithm using a plot of spectral shape relative to the ratio mg i e molar mg mg fe 100 determines the winning model and composition mg is determined with an average difference of 11 15 and 3 8 units before and after a correction is applied respectively mineralogy is determined with an average difference of 5 15 vol depending upon the mineral constituent

radiative transfer mixing models of meteoritic assemblages 1 a spectral mixing model for the expected conditions on asteroid surfaces based on hapke s radiative transfer theory for intimate mixtures is presented this model calculates the visible near infrared reflectance spectrum of an intimate mixture incorporating the modal mineralogy the mineral chemistry the particle size and the degree of space weathering as factors and includes an improved treatment for the spectral effects of coarse grained fe ni metal this model can reproduce the spectra of geologically plausible mixtures of silicate components and meteorites with known mineral abundances chemistry and particle sizes we compare the model spectral effects of the coarse grained fe ni metal naturally present on asteroid surfaces to the spectral effects of submicroscopic iron produced by lunar style space weathering the model spectral effects of large asteroid surface concentrations of coarse grained fe ni metal are similar to the spectral effects of smfe in some cases we model the composition of asteroid 4 vesta and find it to be consistent with a minimally space weathered eucritic composition finally we predict the spectral properties of some example of ordinary chondrite parent bodies when modeled with particle sizes matching the optically dominant particle size of the lunar surface and minimal abundances of smfe these model ordinary chondrite parent bodies plot outside the s iv asteroid field on a band area ratio versus band i center plot we find that a combination of larger particle sizes and increased smfe abundances is the most effective way to move these models into the s iv field

troposphere planetary boundary layer interactions and the evolution of ocean surface density lessons from red sea corals a time series of oxygen isotope d18o measurements of a coral from the northern red sea rs is presented and used as a direct proxy for water surface density rs with a relatively constant subsurface density the generated surface density time series closely tracks water mass formation variability two positive and two negative high amplitude rs anomalies are studied and associated atmospheric and oceanic data are analyzed to understand large scale ocean atmosphere processes the dominant process is lower tropospheric subsidence it dries the boundary layer bl increases surface evaporation and rs and ultimately drives water mass formation the main cause of the subsidence is a temperature increase along the principal axis of the rs from the eastern mediterranean to the convergence zone cz 188 228n the increase entails isentropes sloping down to the southeast crossing pressure surfaces due to their tilt with nearly adiabatic flow along the principal axis air parcels move roughly along the sloped isentropes toward ever increasing pressure that is they subside the subsidence supplies the northern rs bl with upstream air from higher altitudes where humidity is low thus drying the bl the resultant high evaporation north of 258n with low evaporation minus precipitation south of 228n depresses sea levels in the northern rs and thus drives the rs thermohaline circulation and controls water mass formation excluded from the presented picture but probably very important is mixing with the hot dry air of the surrounding deserts

s type asteroids ordinary chondrites and space weathering the evidence from galileo s fly bys of gaspra and ida new observations of the s type asteroids gaspra and ida especially by the galileo spacecraft demonstrate that a space weathering process operates which modifies the reflectance spectra of fresh material to be redder straighter and have shallower absorption bands the weathering process appears similar to but less potent than that observed on the moon it operates in the sense that it would tend to convert spectra of ordinary chondrites oc to having the spectral traits of s type asteroids these results appear to resolve the major obstacles of the long standing s type conundrum about the provenance of ordinary chondrite meteorites a wide body of recent research which is reviewed here builds on previous meteoritical evidence to support a new developing consensus that the larger s type asteroids are a diverse assortment of silicaceous assemblages which includes the ordinary chrondite parent bodies recent fairly realistic laboratory simulations of space weathering processes have changed oc spectra to resemble s type spectra j f bell s highly regarded earlier paradigm that oc parent bodies would be found only among sub 10 km main belt asteroids has been tested by an extensive observational survey by r binzel and his proteges the result is that no small main belt analog for the ocs has been found not even the somewhat oc like object boznemcova this article reviews the history of the s type conundrum which set the stage for galileo s historic flybys i review the findings about gaspra and ida including results about their geology their geophysical structure and probable origins and about ida s small moonlet dactyl density constraints on ida set by dactyl s orbit rule out for ida at least the classic view of s types as metallic stripped cores of differentiated precursor asteroids new analysis of the galileo spectral images of ida is presented that provides strong evidence that space weathering occurs on ida and that ida and the koronis family asteroids in general are plausibly oc like in composition after reviewing 1990s developments on the s type conundrum i advocate a new perspective that the ordinary chondrite parent bodies are among the s type asteroids a diverse grouping that also contains other silicaceous and silicate metal assemblages presumably including various stony irons and primitive achondrites represented in meteorite collections gaspra may be such a metal rich assemblage

re examination of the lunar magma ocean cumulate overturn hypothesis melting or mixing is required abstract there is a long standing hypothesis that the last fraction of the lunar magma ocean crystallized into a layer of dense ti rich cumulate minerals at shallow depths 100 km early in the moon s history many questions remain about the stability of these high ti cumulates it has been suggested that the cumulates subsequently sank deep into the moon because of gravitational instability but high ti material is required at shallower depths by 3 5 ga to create the high ti mare basalts and picritic glasses the high ti material may have re erupted from depth or some or all of it may have remained at shallow depths throughout lunar history data on phase stabilities bulk compositions densities and temperatures of melting and crystallizing in addition to results from numerical modeling suggest that the high ti cumulates would sink only under highly specific conditions five scenarios for sinking high ti cumulate materials are examined and only two are found plausible in particular it is found that simple sinking of solidified high ti cumulates is unlikely because the temperature at which the cumulates solidify is low and viscosity under these conditions is very high it is however possible that high ti cumulates mixed with a substantial fraction of olivine would have viscosity low enough to allow them to sink as solids further because clinopyroxene and ilmenite melt in a ratio of 2 1 remelted high ti cumulates would be negatively buoyant and sink as liquids percolating downward through the underlying mantle and beginning to recrystallize ilmenite at 200 km depth making a hybrid heterogeneous mantle

mineralogy of the mafic anomaly in the south pole aitken basin implications for excavation of the lunar mantle the mineralogy of south pole aitken basin spa the largest confirmed impact basin on the moon is evaluated using five color images from clementine although olivine rich material as well as basalts rich in clinopyroxene are readily identified elsewhere on the farside the dominant rock type observed across the interior of spa is of a very noritic composition this mineralogy suggests that lower crust rather than the mantle is the dominant source of the mafic component at spa the lack of variation in observed noritic composition is probably due to basin formation processes during which extensive melting and mixing of target materials are likely to occur

on the separability of the north atlantic oscillation and arctic oscillation we address the issue of whether the arctic ao and north atlantic oscillations nao are inseparable forming an annular mode in the northern hemisphere atmospheric circulation this annular mode is the leading empirical orthogonal function of hemispheric sea level pressure slp data explaining the largest amount of its variability we examine whether the nao and ao are inseparable spatial modes of the atmospheric circulation using rotated principal component analysis rpca a methodology that identifies simple and unique patterns of spatial dataset variability rpca of the spring summer and autumn slp fields from 1946 1998 reveal nao and ao like patterns occurring as separate regional teleconnections forming the first and second principal components respectively the rpca based nao dipole pattern is like that observed in many prior studies while the ao like pattern exhibits high slp variability over the kara and laptev seas during winter however and in annual analyses a distinct ao like pattern is not obtained and the two patterns may be inseparable using commonly accepted rpca methods the rpca based ao like mode is significantly linked to north central siberian seasonal air temperatures and to the prevailing direction of motion of the underlying arctic ocean in summer suggesting that the non winter ao like pattern as a stand alone teleconnection separate from the nao contributes significantly to high latitude climate and ocean variability the winter nao ao inseparability is discussed as a possible effect of a shared winter storm track between the northeastern atlantic and the arctic

a coral oxygen isotope record from the northern red sea documenting nao enso and north pacific teleconnections on middle east climate variability since the year 1750 a 245 year coral oxygen isotope record from the northern red sea ras umm sidd egypt 28 n in bimonthly resolution is presented the mean annual coral 18o signal apparently reflects varying proportions of both sea surface temperature and 18oseawater variability in conjunction with instrumental observations of climate the coral record suggests for interannual and longer timescales that colder periods are accompanied by more arid conditions in the northern red sea but increased rainfall in the southeastern mediterranean whereas warmer periods are accompanied by decreased rainfall in the latter and less arid conditions in the northern red sea a 70 year oscillation of probably north atlantic origin dominates the coral time series interannual to interdecadal variability is correlated with instrumental indices of the north atlantic oscillation nao the el nino southern oscillation enso and north pacific climate variability the results suggest that these modes contributed consistently to middle east climate variability since at least 1750 preferentially at a period of 5 7 years

the importance of ship log data reconstructing north atlantic european and mediterranean sea level pressure fields back to 1750 local to regional climate anomalies are to a large extent determined by the state of the atmospheric circulation the knowledge of large scale sea level pressure slp variations in former times is therefore crucial when addressing past climate changes across europe and the mediterranean however currently available slp reconstructions lack data from the ocean particularly in the pre 1850 period here we present a new statistically derived 5 5 resolved gridded seasonal slp dataset covering the eastern north atlantic europe and the mediterranean area 40 w 50 e 20 n 70 n back to 1750 using terrestrial instrumental pressure series and marine wind information from ship logbooks for the period 1750 1850 the new slp reconstruction provides a more accurate representation of the strength of the winter westerlies as well as the location and variability of the azores high than currently available multiproxy pressure field reconstructions these findings strongly support the potential of ship logbooks as an important source to determine past circulation variations especially for the pre 1850 period this new dataset can be further used for dynamical studies relating large scale atmospheric circulation to temperature and precipitation variability over the mediterranean and eurasia for the comparison with outputs from gcms as well as for detection and attribution studies

space weathering on airless bodies resolving a mystery with lunar samples using new techniques to examine the products of space weathering of lunar soils we demonstrate that nanophase reduced iron npfe0 is produced on the surface of grains by a combination of vapor deposition and irradiation effects the optical properties of soils both measured and modeled are shown to be highly dependent on the cumulative amount of npfe0 which varies with different starting materials and the energetics of different parts of the solar system the measured properties of intermediate albedo asteroids the abundant s type asteroids in particular are shown to directly mimic the effects predicted for small amounts of npfe0 on grains of an ordinary chondrite regolith this measurement and characterization of space weathering products seems to remove a final obstacle hindering a link between the abundant ordinary chondrite meteorites and common asteroids

pyroxene spectroscopy revisited spectral compositional correlations and relationship to geothermometry the authors wish to thank the various agencies which have provided the necessary support for this project including grants in aid of research from sigma xi the scientific research society to e a c the geological society of america grant 3741 87 to e a c and nasa planetary geology and geophysics grant nagw 642 to m j g

deconvolving the δ18o seawater component from subseasonal coral δ18o and sr ca at rarotonga in the southwestern subtropical pacific for the period 1726 to 1997 to reconstruct oceanographic variations in the subtropical south pacific 271 year long subseasonal time series of sr ca and delta 18 o were generated from a coral growing at rarotonga 21 5degreess 159 5degreesw in this case coral sr ca appears to be an excellent proxy for sea surface temperature sst and coral delta 18 o is a function of both sst and seawater delta 18 o composition delta 18 o sw here we focus on extracting the delta 18 o sw signal from these proxy records a method is presented assuming that coral sr ca is solely a function of sst and that coral delta 18 o is a function of both sst and delta 18 o sw this method separates the effects of delta 18 o sw from sst by breaking the instantaneous changes of coral delta 18 o into separate contributions by instantaneous sst and delta 18 o sw changes respectively the results show that on average delta 18 o sw at rarotonga explains similar to39 of the variance in delta 18 o and that variations in sst explains the remaining similar to61 of delta 18 o variance reconstructed delta 18 o sw shows systematic increases in summer months december february consistent with the regional pattern of variations in precipitation and evaporation the delta 18 o sw also shows a positive linear correlation with satellite derived estimated salinity for the period 1980 to 1997 r 0 72 this linear correlation between reconstructed delta 18 o sw and salinity makes it possible to use the reconstructed delta 18 o sw to estimate the past interannual and decadal salinity changes in this region comparisons of coral delta 18 o and delta 18 o sw at rarotonga with the pacific decadal oscillation index suggest that the decadal and interdecadal salinity and sst variability at rarotonga appears to be related to basin scale decadal variability in the pacific copyright c 2002 elsevier science ltd

compositional variations of the lunar crust results from radiative transfer modeling of central peak spectra 1 we present model mineralogy of impact crater central peaks combined with crustal thickness and crater central peak depth of origin models to report multiple perspectives of lunar crustal composition with depth here we report the analyses of 55 impact crater central peaks and how their compositions directly relate to the lunar highlands sample suite a radiative transfer model is used to analyze clementine visible plus near infrared spectra to place compositional constraints on these central peak materials central peaks analyzed are dominantly magnesian and plagioclase poor strong compositional similarities to lunar mg suite materials are evident relative to crustal thickness estimates central peak mineralogy becomes more plagioclase rich as the crust thickens relative to the crust mantle boundary the origin of peaks with dominantly mafic mineralogy are confined to the lower crust and primarily within the south pole aitken and procellarum kreep terranes pkt additionally central peaks with anorthositic mineralogy 60 vol plagioclase are transported to the surface from all depths in the crustal column and confined to the feldspathic highlands terrane fht the discovery of mafic and magnesian materials consistent with mg suite rocks of the sample collection in all lunar terranes suggests that the process and sources that give rise to these types of rocks is not unique to the pkt and not necessarily dependent on incompatible elements for formation the identification of ferroan and magnesian anorthositic material near the crust mantle boundary of the fht is also inconsistent with an increasing mafic feldspar ratio and mg with depth in the crust

model near infrared optical constants of olivine and pyroxene as a function of iron content the imaginary coefficients of the complex index of refraction of olivine low ca orthopyroxene and high ca clinopyroxene are derived as a function of iron content and wavelength over the spectral region 0 4 to 2 5 m from reflectance spectra of powders and hapke radiative transfer theory reflectance spectra as a function of composition and grain size are computed and compared i find that while spectral effects of variations in these parameters are similar they are distinguishable variations in iron content do not explain all the observed spectral variations in the spectra of the samples investigated

classification seasonality and persistence of low frequency atmospheric circulation patterns abstract orthogonally rotated principle component analysis rpca of northern hemisphere 1 month mean 700 mb heights is used to identify and describe the seasonality and persistence of the major modes of interannual variability the analysis is detailed and comprehensive in that 1 a high resolution approximately equal area 358 point grid is used for the virtually maximum possible 35 year period of record 2 a positive bias in the nmc data base in the early 1950s in the subtropics is largely eliminated for the first time and 3 homogeneous separate analyses of each month of the year are carried out detailing the mouth to month changes in the dominant circulation patterns winter results are similar to those of other recent rpca and teleconnection studies except that some less obvious patterns are identified and further detail of the better known patterns is provided two north south dipole patterns are found over the pacific ocean west pacific oscillation and east pacific pattern and over the atla

persistent positive north atlantic oscillation mode dominated the medieval climate anomaly the medieval climate anomaly mca was the most recent pre industrial era warm interval of european climate yet its driving mechanisms remain uncertain we present here a 947 year long multidecadal north atlantic oscillation nao reconstruction and find a persistent positive nao during the mca supplementary reconstructions based on climate model results and proxy data indicate a clear shift to weaker nao conditions into the little ice age lia globally distributed proxy data suggest that this nao shift is one aspect of a global mca lia climate transition that probably was coupled to prevailing la nina like conditions amplified by an intensified atlantic meridional overturning circulation during the mca

using the modified gaussian model to extract quantitative data from lunar soils 1 the lunar soil characterization consortium lscc has examined and characterized a suite of lunar soils with a wide range of compositions and maturities the purpose of this study is to compare the vis nir spectral properties of these lunar soils with their petrologic and chemical compositions using the modified gaussian model mgm to obtain quantitative data about the character of relatively weak near infrared absorption bands useful compositional information can be extracted from high quality soil spectra using the mgm the model had some difficulty fitting absorption bands in the 2 mm region of the lunar spectrum but bands in the 1 and 1 2 mm regions provided physically realistic results the model was able to distinguish high ca and low ca pyroxenes in the lscc suite of lunar soils in the appropriate relative abundance in addition unexpected insights into the nature and causes of absorption bands in lunar soils were identified for example at least two distinct absorption bands are required in the 1 2 mm region of the spectrum and neither of these bands can be attributed to plagioclase or agglutinates but are found instead to be largely due to pyroxene

pristine lunar glasses criteria data and implications major element analyses of several thousand glasses from all of the apollo landing sites have resulted in the identification of 25 groups of pristine i e volcanic glass the nickel in these pristine glasses is shown to be indigenous not meteoritic contamination and to be correlated with mg the chemical data indicate that these glasses are consistently better candidates for primary magmas than the majority of crystalline mare basalts the pristine glasses support the view that assimilative processes ringwood and kesson 1976 involving two cumulate systems in the differentiated mantle operated during mare petrogenesis the reality of those assimilative interactions is evident by the occurrence of two linear arrays among the chemistries of the glasses data suggest that these cumulate components in the differentiated mantle persist for lateral distances of at least 1000 km and therefore appear to be products of a vast magma ocean that existed early in lunar history alternative hypotheses claiming that the highlands crust and mare source regions were produced by serial magmatism without a magma ocean have not yet considered all of the constraints derived from the pristine glasses

the geology of gaspra the surface of gaspra can be divided into several facets separated by ridges superimposed on the facets and ridges are two populations of craters type 1 craters are crisply defined and constitute a production function of impact origin type 2 craters are mostly irregular shallow depressions and probably of various origins some of the type 2 craters may have formed by impact and be remnants of a crater population that predates the type 1 population the number of type 1 craters suggests that they started to accumulate 2 107 to 3 108 years ago the freshest craters have a depth diameter ratio of 1 7 as compared with 1 5 typically observed on other bodies the craters appear to have become shallower with age at a rate of 10 6 to 10 7 m year the shallow depth of newly formed craters and the progressive degradation with age are ascribed to downslope movement of poorly coherent surface materials the movement being aided by seismic shaking as a result of impact the surface shows subtle color differences the most prominent differences are observed around craters on ridges where the surface has a stronger 1 m absorption than elsewhere the contrast is not observed around craters on the facets the color differences are attributed to alteration of the materials brought to the surface the unaltered material is estimated to be located at least 50 m below the surface on the facets only on the ridges is unaltered material at a shallow enough depth to be excavated by the observed craters the rate of degradation of craters the rounded form of the ridges the depth of altered material on the facets and the presence of old degraded craters all suggest that gaspra is covered with a regolith a few tens to several tens of meters thick

monsoons and the dynamics of deserts the existence of subtropical deserts such as the sahara has often been attributed to the annual mean zonal mean hadley circulation which shows strong descent in the subtropics however the zonal mean hadley circulation shows considerable evolution over the course of the year with very strong subtropical descent during winter but practically no zonal mean subtropical descent during summer when rainfall over the eastern sahara and the mediterranean is least charney 1975 proposed a biosphere albedo feedback mechanism whereby local anthropogenic effects related to over grazing could affect the radiative balance enhancing summertime diabatic descent and leading to desertification of the subtropics in general the present study which uses an idealized model suggests a monsoon desert mechanism for desertification whereby remote diabatic heating in the asian monsoon region can induce a rossby wave pattern to the west integral with the rossby wave solution is a warm thermal structure that interacts with air on the southern flank of the mid latitude westerlies causing it to descend this adiabatic descent is localized over the eastern sahara and mediterranean and over the kyzylkum desert to the south east of the aral sea by the mountains of north africa and south west asia trajectories indicate that the monsoon desert mechanism does not represent a simple walker type overturning cell instead the descending air is seen to be mainly of mid latitude origin it is speculated that the monsoon forced adiabatic descent may result in clear air and therefore a local diabatic enhancement which effectively doubles the strength of descent with this mechanism desertification can be forced by remote changes in monsoon strength rather than by local effects this conclusion is supported by the observed dramatic strengthening of descent over the mediterranean and east sahara during the onset of the asian monsoon and on the longer timescale by relating prehistoric lake levels to milankovitch monsoon forcing the latter may help to explain the perceived discrepancies between the palaeoclimate of the eastern sahara and the strength of a tropic wide monsoon the monsoon desert mechanism may not be confined to the asian monsoon alone and the existence of other monsoon climate regions over the globe may in a similar way explain the observed summertime strengthening of the oceanic sub tropical anticyclones and the existence of western continental deserts and mediterranean type climate regions

mineralogical and chemical characterization of lunar highland soils insights into the space weathering of soils on airless bodies 1 with reflectance spectroscopy one is measuring only properties of the fine grained regolith most affected by space weathering the lunar soil characterization consortium has undertaken the task of coordinated characterization of lunar soils with respect to their mineralogical and chemical makeup it is these lunar soils that are being used as ground truth for all airless bodies modal abundances and chemistries of minerals and glasses in the finest size fractions 20 45 10 20 and 10 m of four apollo 14 and six apollo 16 highland soils have been determined as well as their bulk chemistry and is feo values bidirectional reflectance measurements 0 3 2 6 m of all samples were performed in the reflectance experiment laboratory a significant fraction of nanophase fe0 np fe0 appears to reside in agglutinitic glasses however as grain size of a soil decreases the percentage of total iron present as np fe0 increases significantly whereas the agglutinitic glass content rises only slightly this is evidence for a large contribution to the is feo values from the surface correlated nanophase fe0 particularly in the 10 m size fraction the compositions of the agglutinitic glasses in these fine fractions of the highland soils are different from the bulk chemistry of that size however compositional trends of the glasses are not the same as those observed for mare soils it is apparent that the glasses in the highland soils contain chemical components from outside their terrains it is proposed that the apollo 16 soils have been adulterated by the addition of impact transported soil components from surrounding maria

composition of the lunar surface as will be seen from smart 1 a simulation using clementine data 1 we present a new technique for remote sensing determination of lunar surface composition in the context of the smart 1 mission the technique is based on spectral and composition data obtained by lunar soil characterization consortium for a few particle size separates of lunar soils we map the abundance of tio2 and feo pyroxene content maturity degree is feo and a characteristic size of particles comparison of the tio2 and feo abundance maps with proper distributions obtained by lucey et al 2000a shows high correlation we found also an inverse correlation between the is feo distribution and lucey et al s 2000b parameter om application of this approach shows that fresh mare crater regolith is characterized with a higher abundance of pyroxenes coarse particles and low maturity degree the pyroxene abundance map can be used to identify pyroclastic regions an excess of small particles is predicted for highland areas we note appreciable variations of the characteristic size of particles in mare regions our preliminary results for the reiner formation show that there is no composition anomaly for the tio2 and feo abundance in agreement with previous analyses our maps also indicate that the formation contains a surface material characterized with low maturity and high degree of crystallinity consistent with the occurrence of immature regolith possibly contaminated with dust

the magma ocean concept and lunar evolution the model of lunar evolution in which the anorthositic plagioclase rich oldest crust of the moon is formed over a period of 300 myr or less by crystallization as it floats on a global ocean of magma tens or hundreds of km thick is examined in a review of petrological and theoretical studies consideration is given to the classification of lunar rocks the evidence for primordial deep global differentiation constraints on the depth of the molten zone the effects of pressure on mineral stability relationships mainly liquid vs mainly magmifer ocean models and the evidence for multiple ancient differentiation episodes a synthesis of the model of primordial differentiation and its aftereffects is presented and the generalization of the model to the earth and to mars mercury venus and the asteroids is discussed

regional effects of the mount pinatubo eruption on the middle east and the red sea the 1991 eruption of mount pinatubo had dramatic effects on the regional climate in the middle east though acknowledged these effects have not been thoroughly studied to fill this gap and to advance understanding of the mechanisms that control variability in the middle east s regional climate we simulated the impact of the 1991 pinatubo eruption using a regional coupled ocean atmosphere modeling system set for the middle east and north africa mena domain we used the coupled ocean atmosphere wave sediment transport coawst framework which couples the weather research and forecasting model wrf model with the regional oceanic modeling system roms we modified the wrf model to account for the radiative effect of volcanic aerosols our coupled ocean atmosphere simulations verified by available observations revealed strong perturbations in the energy balance of the red sea which drove thermal and circulation responses our modeling approach allowed us to separate changes in the atmospheric circulation caused by the impact of the volcano from direct regional radiative cooling from volcanic aerosols the atmospheric circulation effect was significantly stronger than the direct volcanic aerosols effect we found that the red sea response to the pinatubo eruption was stronger and qualitatively different from that of the global ocean system our results suggest that major volcanic eruptions significantly affect the climate in the middle east and the red sea and should be carefully taken into account in assessments of long term climate variability and warming trends in mena and the red sea

lunar soil characterization consortium analyses pyroxene and maturity estimates derived from clementine image data abstract the mineralogy of a planetary surface is a diagnostic product of its formation and geologic evolution global assessment of lunar mineralogy at high spatial resolution has been a long standing goal of lunar exploration currently the only global data available for such study is multispectral imagery from the clementine mission we use the detailed compositional petrographic and spectroscopic data of lunar soils produced by the lunar soil characterization consortium to explore the use of multispectral imaging as a diagnostic tool we compare several statistically optimized formulations of links between spectral and mineral parameters and apply them to clementine uv vis data the most reliable results are for estimations of pyroxene abundance and maturity parameters agglutinate abundance i s feo estimations of different pyroxene composition low ca versus high ca appear good in a relative sense but absolute values are limited by residual wavelength dependent clementine photometric calibrations since the signal to noise of clementine multispectral data is good at the 1 km scale almost any combination of parameters that capture inherent spectral variance can provide spatially coherent maps although the parameters may not actually be directly related to composition clementine estimates are useful for identifying scientific or exploration targets for imaging spectrometer sensors of the next generation that are specifically designed to characterize mineralogy

a snapshot of climate variability at tahiti at 9 5 ka using a fossil coral from iodp expedition 310 1 the integrated ocean drilling program iodp expedition 310 recovered drill cores from the drowned reefs around the island of tahiti 17 40 s 149 30 w many of which contained samples of massive corals from the genus porites herein we report on one well preserved fossil coral sample a 13 6 cm long porites sp dated by uranium series techniques at 9523 33 years monthly 18o and sr ca determinations reveal nine clear and robust annual cycles coral 18o and sr ca determinations estimate a mean temperature of 24 3 c 3 2 c colder than modern for tahiti at 9 5 ka however this estimate is viewed with caution since potential sources of cold bias in coral geochemistry remain to be resolved the interannual variability in coral 18o is similar between the 9 5 ka coral record and a modern record from nearby moorea the seasonal cycle in coral sr ca is approximately the same or greater in the 9 5 ka coral record than in modern coral records from tahiti paired analysis of coral 18o and sr ca indicates cold wet warm dry interannual anomalies opposite from those observed in the modern instrumental record

pedogenic properties of white clay soils of the three river plain heilongj iang province p r china abstract white clay soils are widely distributed in the heilongjiang province p r china and are of agricultural importance in the province however there is only limited information available on the characteristics and pedogenesis of these soils three representative pedons of white clay soils in the three river plain heilongjiang province were selected to determine physical morphological chemical and mineralogical properties and to relate these properties to the genesis and classification of these soils sr ti and zr were determined by x ray fluorescence to establish parent material uniformity clay minerals were identified by x ray diffraction methods micromorphology of the soils was based on petrographic examination of thin sections lithologic discontinuities were not detected based on the coefficients of variability associated with ratios of zr sr and ti zr within pedons the profiles are characterized by a mollic epipedon an albic e horizon and a thick argillic horizon physical morphological chemical and mineralogical properties indicate that lessivage was a dominant pedogenic process pedogenic fe mn nodules occur in ah and e horizons maximum contents of pyrophosphate extractable fe and al and oxalate and dithionite extractable al occur in bt2 horizons the soils have relatively uniform ph values of about 4 5 5 0 soil vermiculite which had not previously been recognized is common in the clay fraction the clay mineral assemblage is qualitatively similar throughout profiles continuous addition of aerosolic dust rich in mica and lessivage contributed to the quantitative variation in clay minerals within the pedon the white clay soils are classified as mollic planosols in the fao unesco system and typic argialbolls in soil taxonomy

reconstructing seawater δ18o from paired coral δ18o and sr ca ratios methods error analysis and problems with examples from tahiti french polynesia and timor indonesia we compare several statistical routines that may be used to calculate delta o 18 and sss from paired coral sr ca and delta o 18 measurements typically the delta o 18 coral sst relationship is estimated by linear regression of coral delta o 18 vs sst if this method is applied evidence should be given that at a particular site sst and sss do not co vary in the tropical oceans sst and delta o 18 sw sss often co vary and this will bias the estimate of the regression slope of delta o 18 coral sst using a stochastic model we show that covariance leads to a bias in the coefficients of the univariate regression equations as the slope of the delta o 18 coral sst relationship has known we propose to insert this value for gamma 1 in the regression models this requires that the constants of the regression equations are removed to omit the constants we propose to center the regression equations i e to remove the mean values from the variables the statistical error propagation is calculated to assess our ability to resolve past variations in delta o 18 sw sss at tahiti we find that the combined analytical uncertainties of coral delta o 18 and sr ca equal the amplitude of the seasonal cycle of delta o 18 sw sss therefore we cannot resolve the seasonal cycle of sss at tahiti at timor the error of reconstructed delta o 18 sw sss is lower than the magnitude of seasonal variations of delta o 18 sw sss and the seasonal cycle of delta o 18 sw sss can be resolved c 2008 elsevier ltd all rights reserved

space weathering from mercury to the asteroid belt the variety of evidence bearing on the nature of space weathering is reviewed the effects of space weathering include spectral darkening reddening and subdued absorption bands and the distinctive magnetic electron spin resonance caused by single domain metallic iron particles ever since the apollo missions two paradigms have dominated the thinking of the planetary science community concerning space weathering 1 the optical effects are caused by impact vitrified glass in agglutinates and 2 the submicroscopic metallic iron results from the reduction of ferrous iron by the impact melting of minerals whose surfaces have been saturated with hydrogen from the solar wind however studies carried out since the apollo program showed that both of these paradigms are invalid a hypothesis first suggested by the author and his colleagues 26 years ago but not generally accepted at that time now appears to be essentially correct both the optical and magnetic effects are caused by metallic iron particles smaller than the wavelength in ubiquitous vapor deposited coatings on soil particle surfaces and inside agglutinates the vapor is generated by both solar wind sputtering and micrometeorite impact vaporization and injected preferentially downward into the porous regolith the iron is reduced by a physical process the selective loss of oxygen that occurs during deposition of the vapor and does not require heating melting or a reducing environment a mathematical theory that describes the optical effects of the submicroscopic iron quantitatively is derived and applied to the regoliths of the moon mercury and an s asteroid

crustal diversity of the moon compositional analyses of galileo solid state imaging data the multispectral images of the lunar limb and farside obtained by the solid state imaging ssi system on board the galileo spacecraft provide the first new pulse of compositional data of the moon by a spacecraft in well over a decade the wavelength range covered by ssi filters 0 4 1 0 m is particularly sensitive to the composition of mare basalts the abundance of mafic ferrous minerals and the maturity of the regolith to a first order the limb and farside material is consistent with previous characterization of nearside lunar spectral types for mare and highland soils and craters most basalts are of an intermediate tio 2 composition and most of the highland crust is feldspathic with local variations in mafic content identified principally at impact craters dark manfling material on the farside can be interpreted in terms of known properties of lunar pyroclastic glass regions of cryptornate are shown to have spectral properties intermediate between those of highland and mare soils as would be expected from a mixture of the two there are several important exceptions and surprises however unlike the basalt types identified on the nearside limb and farside basalts exhibit an exceptionally weak 1 xm ferrous absorption band this may indicate a compositionally distinct lunar basalt group that for example is more mg rich than most basalts of the nearside some of the most notable compositional anomalies are associated with south pole aitken basin this large region has a much lower albedo than surrounding highlands the inner darkest portion of the basin exhibits optical properties indistinguishable low ti basalts deposits to the south exhibit unique properties with a strong and broad ferrous 1 xrn absorption most consistent with abundant olivine the unusual compositions associated with south pole aitken and their spatial e3tent suggests the impact creating this huge lunar basin excavated mafic rich lower crust or perhaps mantle material 1 intro oucri ion

classification and distribution of soils with albic horizons in the usa a preliminary analysis abstract the albic horizon a diagnostic subsurface horizon that is comprised of primary sand and silt particles that are light colored because they lack clay or iron oxide coatings is unique in that it is an eluvial horizon that is defined on the basis of a loss rather than a gain of weathering products over 3000 official soil descriptions were examined in the us natural resources conservation service databases to identify which taxa contain albic horizons albic horizons are present i e more than 8 soil series in seven orders 28 suborders 73 great groups and about 1600 soil series in soil taxonomy orders with albic horizons can be ranked on an area basis alfisols spodosols ultisols mollisols inceptisols entisols aridisols the mean thickness of the albic horizon is 19 cm with the greatest thickness in alorthods 90 cm and the least in xerolls 3 1 humods 4 0 and ustolls 5 6 cm albic horizons may occupy one or two of several positions in the soil profile including i the mineral soil surface ii below an a horizon iii as a buried horizon iv between a variety of diagnostic subsurface horizons in bisequal soils and v in some soils with alternating e and bt lamellae albic horizons separate or are underlain mainly by an argillic or a spodic horizon half 50 of the soils with albic horizons are excessively to well drained many albic horizons have been lost due to cultivation especially in aqualfs udalfs and udults

radiative transfer modeling of lunar highlands spectral classes and relationship to lunar samples 1 tompkins and pieters 1999 identified eleven spectral classes present on the surface of the moon here we model these spectral classes to determine the compositions that define them we do this by mathematically matching spectral classes to radiative transfer computed spectra using spectral shape contrast and excursion parameters as defining characteristics model spectra are based upon known mineralogies mafic mineral mg s molar mg mg fe 100 and maturities we compare these compositional results to a compilation of 100 apollo samples to determine plausible representative samples for these spectra results indicate that unique mineralogic solutions for several spectral classes can be determined unambiguously however classes previously interpreted to be pyroxene rich are compositionally ambiguous results suggest these ambiguous mineral assemblages are not random but correlate with variations in absolute reflectance these data further suggest absolute reflectance is a compositionally diagnostic spectral parameter that should be used in conjunction with relative reflectance analysis to constrain mineralogy although absolute reflectance for the eleven spectral classes is not available to constrain their composition we detail mineral chemical i e mg and absolute reflectance variations of matching model relative reflectance spectra to narrow the possibilities this information is used in a pilot study of bullialdus crater for which clementine absolute reflectance is known results indicate bullialdus s central peak consists of tompkins and pieters spectral classes an agn and n bullialdus s spectra that match class n are roughly consistent with previous compositional interpretations however matches to classes an and agn indicate more mafic assemblages typical of mg suite norite gabbronorite rocks

atmospheric circulation variability in the north atlantic european area since the mid seventeenth century based on monthly mean sea level pressure grids objectively reconstructed by luterbacher et al variations of dynamical modes of the atmospheric circulation for january and july are described by novel indices for running 31 year periods between 1659 and 1999 these indices reflect the continuous evolution of the atmospheric circulation not only with regard to frequency changes of major dynamical modes but also in terms of internal changes within each mode concerning both dynamic vorticity intensity and climatic properties central european temperature and precipitation during occurrence of each mode respectively results indicate the great importance of within mode variations the zonal circulation mode in january varying in frequency with long term cycles primarily changed its dynamic and climatic properties towards higher indices during the transition from the little ice age to modern conditions between 1800 and 1930 within the russian high mode of january a change in preference from easterly to westerly patterns above central europe occurred around 1850 for july a striking frequency maximum of the westerly mode at the end of the eighteenth century coincided with a period of marked summer warmth in central europe due to negative positive deviations in vorticity temperature during occurrence of this mode the long term evolution in july indicates a general increase of anticyclonic conditions strengthening during the last 50 years towards a unique phenomenon within the last centuries the strong increase in the winter time westerly circulation during the last decades however does not appear extraordinary in view of the low frequency variations of this mode

vertical water mass mixing and plankton blooms recorded in skeletal stable carbon isotopes of a red sea coral the environmental interpretation of the 13c 12c variations in the skeletons of massive corals is still a matter of debate a 19 year seasonal skeletal 13c 12c record of a shallow water porites coral from the northern red sea gulf of aqaba documents interannual events of extraordinarily large plankton blooms indicated by anomalous 3c depletions in the coral skeleton these blooms are caused by deep vertical water mass mixing convectively driven in colder winters which results in increased supplies of nutrients to the surface waters the deep vertical mixings can sometimes be driven by the cooling occurring throughout the middle east after large tropical volcanic eruptions we therefore have evidence in our coral skeletal 13c 12c record for an indirect volcanic signal of the eruptions of e1 chich6n 1982 and mount pinatubo 1991 deep mixing induced 13c 12c variations of the dissolved inorganic carbon in the surface waters can be neglected at this location we therefore suggest that the 3c skeletal depletions can be best explained by changes in the coral s autotrophy heterotrophy diet through increased heterotrophic feeding on zooplankton during the blooms increased feeding on 3c depleted zooplankton or increased heterotrophy at the expense of autotrophy can both 3 result in a c depleted coral skeleton however this suggestion requires more testing if our conclusions are substantiated seasonal skeletal 3c r2c records of corals which change from autotrophy under normal conditions to increased heterotrophy during bloom events may be used as indicators of ocean paleoproductivity at interannual resolution available from no other source

imaging of small scale features on 433 eros from near evidence for a complex regolith on 25 october 2000 the near earth asteroid rendevous near shoemaker spacecraft executed a low altitude flyover of asteroid 433 eros making it possible to image the surface at a resolution of about 1 meter per pixel the images reveal an evolved surface distinguished by an abundance of ejecta blocks a dearth of small craters and smooth material infilling some topographic lows the subdued appearance of craters of different diameters and the variety of blocks and different degrees of their burial suggest that ejecta from several impact events blanketed the region imaged at closest approach and led to the building up of a substantial and complex regolith consisting of fine materials and abundant meter sized blocks

mineralogy of the lunar crust results from clementine received 1997 december 5 accepted in revised form 1998 september 15 abstract the central peaks of 109 impact craters across the moon are examined with clementine ultraviolet visible uvvis camera multispectral data the craters range in diameter from 40 to 180 km and are believed to have exhumed material from 5 30 km beneath the surface to form the peaks including both upper and lower crustal rocks depending on whether craters have impacted into highlands or basins representative five color spectra from spectrally and spatially distinct areas within the peaks are classified using spectral parameters including key ratio which is related to mafic mineral abundance and spectral curvature linked to absorption band shape which distinguishes between low and high ca pyroxene and olivine the spectral parameters are correlated to mineralogical abundances related in turn to highland plutonic rock compositions the derived rock compositions for the various central peaks are presented in a global map from these results it is evident that the lunar crust is compositionally diverse both globally and at local 100 m scales found within individual sets of central peaks although the central peaks compositions imply a crust that is generally consistent with previous models of crustal structure they also indicate a more anorthositic crust than generally assumed with a bulk plagioclase content of 8 1 evolving from pure anorthosite near the surface towards more mafic low ca pyroxene rich compositions with depth comparable to anorthositic norite evidence for mafic plutons occurs in both highlands and basins and represent all mafic highland rock types however the lower crust is more compositionally diverse than the highlands with both a greater range of rock types and more diversity within individual sets of central peaks

a high resolution late holocene lake isotope record from turkey and links to north atlantic and monsoon climate a high resolution proxy record of precipitation and evaporation variability through the past 1700 yr from 18o analysis of a varved lake sequence from central turkey shows rapid shifts between dry periods ad 300 500 and ad 1400 1950 and wetter intervals ad 560 750 and ad 1000 1350 changes are consistent with changes in instrumental and proxy records of the indian monsoon dry summers in the eastern mediterranean being associated with periods of enhanced monsoon rainfall in addition major shifts in the record are coherent with changes in north atlantic winter climate with cold wet periods in the alps occurring at times of dry turkish climate

systematic global mixing and melting in lunar soil evolution 1 we present a revised model of soil evolution constrained by the recent lscc data for lunar soils in addition to an observed universal increase in feldspathic components in the finer fractions of soils taylor et al 2001 2003a 2003b both differential melting and lateral mixing processes appear to be required during the evolution of lunar soils we propose mare highland mixing of a significant glass component along with a preferential melting sequence for agglutinitic glass formation of glass plagioclase pyroxene ilmenite

abundance and distribution of iron on the moon the abundance and distribution of iron on the moon is derived from a near global data set from clementine the determined iron content of the lunar highlands crust 3 percent iron by weight supports the hypothesis that much of the lunar crust was derived from a magma ocean the iron content of lower crustal material exposed by the south pole aitken impact basin on the lunar farside is higher 7 to 8 percent by weight and consistent with a basaltic composition this composition supports earlier evidence that the lunar crust becomes more mafic with depth the data also suggest that the bulk composition of the moon differs from that of the earth9s mantle this difference excludes models for lunar origin that require the earth and moon to have the same compositions such as fission and coaccretion and favors giant impact and capture

last millennium northern hemisphere summer temperatures from tree rings part i the long term context abstract large scale millennial length northern hemisphere nh temperature reconstructions have been progressively improved over the last 20 years as new datasets have been developed this paper and its companion part ii anchukaitis et al in prep details the latest tree ring tr based nh land air temperature reconstruction from a temporal and spatial perspective this work is the first product of a consortium called n trend n orthern hemisphere tre e ring n etwork d evelopment which brings together dendroclimatologists to identify a collective strategy for improving large scale summer temperature reconstructions the new reconstruction n trend2015 utilises 54 records a significant expansion compared with previous tr studies and yields an improved reconstruction with stronger statistical calibration metrics n trend2015 is relatively insensitive to the compositing method and spatial weighting used and validation metrics indicate that the new record portrays reasonable coherence with large scale summer temperatures and is robust at all time scales from 918 to 2004 where at least 3 tr records exist from each major continental mass n trend2015 indicates a longer and warmer medieval period 900 1170 than portrayed by previous tr nh reconstructions and by the cmip5 model ensemble but with better overall agreement between records for the last 600 years future dendroclimatic projects should focus on developing new long records from data sparse regions such as north america and eastern eurasia as well as ensuring the measurement of parameters related to latewood density to complement ring width records which can improve local based calibration substantially

radiative transfer modeling for quantifying lunar surface minerals particle size and submicroscopic metallic fe 1 the main objective of this work is to quantify lunar surface minerals agglutinate clinopyroxene orthopyroxene plagioclase olivine ilmenite and volcanic glass particle sizes and the abundance of submicroscopic metallic fe smfe from the lunar soil characterization consortium lscc data set with hapke s radiative transfer theory the mode is implemented for both forward and inverse modeling we implement hapke s radiative transfer theory in the inverse mode in which instead of commonly used look up tables newton s method and least squares are jointly used to solve nonlinear questions although the effects of temperature and surface roughness are incorporated into the implementation to improve the model performance for application of lunar spacecraft data these effects cannot be extensively addressed in the current work because of the use of lab measured reflectance data our forward radiative transfer model results show that the correlation coefficients between modeled and measured spectra are over 0 99 for the inverse model the distribution of the particle sizes is all within their measured range the range of modeled smfe for highland samples is 0 01 0 5 and for mare samples it is 0 03 1 the linear trend between smfe and ferromagnetic resonance is for all the lscc samples is consistent with laboratory measurements for quantifying lunar mineral abundances the results show that the r squared for the training samples is feo 65 are over 0 65 with plagioclase having highest correlation 0 94 and pyroxene having the lowest correlation 0 68 in future work the model needs to be improved for handling more mature lunar soil samples

eros shape topography and slope processes stereogrammetric measurement of the shape of eros using images obtained by near s multispectral imager provides a survey of the major topographic features and slope processes on this asteroid this curved asteroid has radii ranging from 3 1 to 17 7 km and a volume of 2535 20 km3 the center of figure is within 52 m of the center of mass provided by the navigation team this minimal difference suggests that there are only modest variations in density or porosity within the asteroid three large depressions 10 8 and 5 3 km across represent different stages of degradation of large impact craters slopes on horizontal scales of 300 m are nearly all less than 35 although locally scarps are much steeper the area distribution of slopes is similar to those on ida phobos and deimos regions that have slopes greater than 25 have distinct brighter markings and have fewer large ejecta blocks than do flatter areas the albedo patterns that suggest downslope transport of regolith have sharper boundaries than those on phobos deimos and gaspra the morphology of the albedo patterns their lack of discrete sources and their concentration on steeper slopes suggest transport mechanisms different from those on the previously well observed small bodies perhaps due to a reduced relative effectiveness of impact gardening on eros regolith is also transported in talus cones and in connected sinuous paths extending as much as 2 km with some evident as relatively darker material talus material in at least one area is a discrete superposed unit a feature not resolved on other small bodies flat floored craters that apparently contain ponded material also suggest discrete units that are not well mixed by impacts

radiative transfer modeling of compositions of lunar pyroclastic deposits 1 while over 100 lunar pyroclastic deposits have been identified remotely their compositions remain poorly constrained in this work we determine the compositions of three lunar regional pyroclastic deposits which are likely to contain large amounts of glass and for which we have high quality ground based spectra the aristarchus plateau mare humorum and sulpicius gallus we use radiative transfer theory and employ measured optical constants of glasses to predict the bidirectional reflectance of a particulate glass surface as a function of fe and ti concentration particle size and maturity in order to find the best spectral match to the remotely observed deposits tools are not available to model the optical effects of the unusual geometries of the ilmenite laths in the black beads so we address their effects on spectra of the regional pyroclastic deposits using computational mixing we find that model spectra of pure glass as opposed to devitrified black beads provide good matches to all three regions radiative transfer modeling predicts iron contents of 21 20 and 17 wt feo for aristarchus humorum and sulpicius gallus respectively and suggests that all three regions are low in titanium a result supported by lunar prospector neutron spectrometer data however we find that a moderate ti glass mixed with a small fraction of black beads cannot be ruled out for the sulpicius gallus region

increased seasonality in middle east temperatures during the last interglacial period the last interglacial period about 125 000 years ago is thought to have been at least as warm as the present climate owing to changes in the earth s orbit around the sun it is thought that insolation in the northern hemisphere varied more strongly than today on seasonal timescales which would have led to corresponding changes in the seasonal temperature cycle here we present seasonally resolved proxy records using corals from the northernmost red sea which record climate during the last interglacial period the late holocene epoch and the present we find an increased seasonality in the temperature recorded in the last interglacial coral today climate in the northern red sea is sensitive to the north atlantic oscillation a climate oscillation that strongly influences winter temperatures and precipitation in the north atlantic region from our coral records and simulations with a coupled atmosphere ocean circulation model we conclude that a tendency towards the high index state of the north atlantic oscillation during the last interglacial period which is consistent with european proxy records contributed to the larger amplitude of the seasonal cycle in the middle east

mild and arid climate in the eastern sahara arabian desert during the late little ice age the climate of the sahara and arabian deserts during the little ice age is not well known due to a lack of annually resolved natural and documentary archives we present an annual reconstruction of temperature and aridity derived from sr ca and oxygen isotopes in a coral of the desert surrounded northern red sea our data indicate that the eastern sahara and arabian deserts did not experience pronounced cooling during the late little ice age 1750 1850 but suggest an even more arid mean climate than in the following 150 years the mild temperatures are broadly in line with predominantly negative phases of the north atlantic oscillation during the little ice age the more arid climate is best explained by meridional advection of dry continental air from eurasia we find evidence for an abrupt termination of the more arid climate after 1850 coincident with a reorganization of the atmospheric circulation over europe

arctic oscillation signature in a red sea coral we show that the winter time series of the ras umm sidd coral oxygen isotope record from the northern red sea approximately 28 n is linked to the arctic oscillation phenomenon the northern hemisphere s dominant mode of atmospheric variability until now the detection of this mode which is most prominent in winter in proxy climate records was difficult due to the lack of a clear seasonality in most paleoclimatic archives the results suggest that northern red sea corals can provide information about the low frequency variability of the northern hemisphere winter circulation during the pre instrumental period

space weathering on airless planetary bodies clues from the lunar mineral hapkeite physical and chemical reactions occurring as a result of the high velocity impacts of meteorites and micrometeorites and of cosmic rays and solar wind particles are major causes of space weathering on airless planetary bodies such as the moon mercury and asteroids these weathering processes are responsible for the formation of their regolith and soil we report here the natural occurrence of the mineral hapkeite a fe2si phase and other associated fe si phases iron silicides in a regolith breccia clast of a lunar highland meteorite these fe si phases are considered to be a direct product of impact induced vapor phase deposition in the lunar soil all part of space weathering we have used an in situ synchrotron energy dispersive single crystal x ray diffraction technique to confirm the crystal structure of hapkeite as similar to the structure of synthetic fe2si this mineral hapkeite is named after bruce hapke of the university of pittsburgh who predicted the presence and importance of vapor deposited coatings on lunar soil grains some 30 years ago we propose that this mineral and other fe si phases are probably more common in the lunar regolith than previously thought and are directly related to the formation of vapor deposited nanophase elemental iron in the lunar soils

optical effects of space weathering the role of the finest fraction the optical properties of lunar softs are different than those of rocks from which they are derived as a consequence of lunar space weathering soils are darker and exhibit a distinctive red sloped continuum and weaker mineral absorption bands the accumulation of dark glass welded aggregates agglutinates has been thought to account for these optical effects of space weathering on lunar soils spectroscopic analyses of agglutinate separates and size fractions for a suite of lunar softs presented here indicate that the agglutinate paradigm is insufficient to fully account for lunar optical alteration it is the finest fraction of lunar soils 25 gm which constitute 25 wt that dominates the optical properties of the bulk soil unlike size fractions of most silicates for which the finest fraction is the brightest the lunar soil size fractions all have comparable albedos in the short wavelength visible in the near infrared however it is the finest fraction that exhibits the steep red continuum and weak absorption bands the properties of the finest fraction cannot be duplicated by preparing a fine fraction by grinding larger agglutinate rich soil particles these results suggest space weathering on airless bodies is dominated by surface correlated processes perhaps associated with the development of fine grained fe o on or near the surface of grains and the accumulation of the larger agglutinates is not necessarily required to account for lunar optical alteration

mayotte coral reveals hydrological changes in the western indian ocean between 1881 and 1994 we reconstruct the hydrologic history of the tropical western indian ocean by calculating the 18oseawater from coupled coral sr ca and 18o measurements in a massive porites coral from mayotte comoros between 1881 and 1994 we found that the precipitation evaporation balance varies naturally on time scales of 5 6 years and 18 25 years high low ssts are associated with positive negative 18oseawater implying that atmospheric variability is linked with remote climate modes in the indian ocean and the tropical extratropical pacific ocean warm el nino southern oscillation events are associated with a negative freshwater balance at mayotte this case study demonstrates that a much denser network of 18oseawater reconstructions is crucial for understanding the spatial patterns of hydrological conditions

space weathering on eros constraints from albedo and spectral measurements of psyche crater we present combined multi spectral imager msi 0 95 m and near infrared spectrometer nis 0 8 2 4 m observations of psyche crater on s type asteroid 433 eros obtained by the near earth asteroid rendezvous near shoemaker spacecraft at 5 3 km in diameter psyche is one of the largest craters on eros which exhibit distinctive brightness patterns consistent with downslope motion of dark regolith material overlying a substrate of brighter material at spatial scales of 620 m spectrum psyche crater wall materials exhibit albedo contrasts of 32 40 at 0 946 m associated spectral variations occur at a much lower level of 4 8 2 4 we report results of scattering model and lunar analogy investigations into several possible causes for these albedo and spectral trends grain size differences olivine pyroxene and troilite variations and optical surface maturation we find that the albedo contrasts in psyche crater are not consistent with a cause due solely to variations in grain size olivine pyroxene or lunar like optical maturation a grain size change sufficient to explain the observed albedo contrasts would result in strong color variations that are not observed olivine and pyroxene variations would produce strong band correlated variations that are not observed a simple lunar like optical maturation effect would produce strong reddening that is not observed the contrasts and associated spectral variation trends are most consistent with a combination of enhanced troilite a dark spectrally neutral component simulating optical effects of shock and lunar like optical maturation these results suggest that space weathering processes may affect the spectral properties of eros materials causing surface exposures to differ optically from subsurface bedrock however there are significant spectral differences between eros proposed analog meteorites ordinary chondrites and or primitive achondrites and eros freshest exposures of subsurface bright materials after accounting for all differences in the measurement units of our reflectance comparisons we have found that the bright materials on eros have reflectance values at 0 946 m consistent with meteorites but spectral continua that are much redder than meteorites from 1 5 to 2 4 m most importantly we calculate that average eros surface materials are 30 40 darker than meteorites

mineral maps of the moon 1 global maps of the distribution of plagioclase orthopyroxene clinopyroxene and olivine on the moon were derived from radiative transfer analysis of 400 000 clementine uvvis spectra plagioclase inversely correlates with iron while clinopyroxene positively correlates with iron showing these are the major carriers of aluminum and iron respectively the distribution of olivine in the maria agrees with previous studies in the highlands the abundance of olivine is low but ubiquitous at a few percent except within the south pole aitken basin where it is only present in very small exposures in the very anorthositic farside highlands olivine is often the sole mafic mineral the abundance of orthopyroxene is generally low excepting elevated abundances in the nearside highlands and in areas near and within south pole aitken basin mare units with elevated abundances of orthopyroxene are found in some mare and cryptomare deposits distant from the sample return sites

subtropical coral reveals abrupt early twentieth century freshening in the western north pacific ocean instrumental climate observations provide robust records of global land and ocean temperatures during the twentieth century unlike for temperature continuous salinity observations in the surface ocean are scarce prior to 1970 and the magnitude of salinity changes during the twentieth century is largely unknown surface ocean salinity is a major component in climate dynamics as it influences ocean circulation and water mass formation here we present an annually resolved reconstruction of salinity variations in the surface waters of the western subtropical north pacific ocean since 1873 based on bimonthly records of 18o sr ca and u ca in a coral from the ogasawara islands the reconstruction indicates that an abrupt regime shift toward fresher surface ocean conditions occurred between 1905 and 1910 observational atmospheric data suggest that the abrupt freshening was associated with a weakening of the winds that drive the kuroshio current system and the associated subtropical gyre circulation we note that the abrupt early twentieth century freshening in the western subtropical north pacific precedes abrupt climate change in the northern north atlantic by a few years the potential for abrupt regime shifts in surface ocean salinity should be considered in climate predictions for the coming decades

continental scale temperature variability during the past two millennia past global climate changes had strong regional expression to elucidate their spatio temporal pattern we reconstructed past temperatures for seven continental scale regions during the past one to two millennia the most coherent feature in nearly all of the regional temperature reconstructions is a long term cooling trend which ended late in the nineteenth century at multi decadal to centennial scales temperature variability shows distinctly different regional patterns with more similarity within each hemisphere than between them there were no globally synchronous multi decadal warm or cold intervals that define a worldwide medieval warm period or little ice age but all reconstructions show generally cold conditions between ad 1580 and 1880 punctuated in some regions by warm decades during the eighteenth century the transition to these colder conditions occurred earlier in the arctic europe and asia than in north america or the southern hemisphere regions recent warming reversed the long term cooling during the period ad 1971 2000 the area weighted average reconstructed temperature was higher than any other time in nearly 1 400 years

properties and genesis of argialbolls in the usa abstract the presence of an albic horizon below a mollic epipedon has long puzzled pedologists the purpose of this study was to utilize data from the natural resources conservation service nrcs databases and the published literature to develop a weight of evidence assessment of how albolls form in the usa there are 69 albolls soil series in the nrcs database all of which are argialbolls these soils contain horizons with the following mean thickness and standard deviation mollic epipedon 29 11 cm albic 18 9 cm and argillic 75 37 cm argialbolls comprise 18 078 km2 in the usa 0 02 of total land area 70 of which occur in north dakota south dakota missouri and iowa argialbolls are somewhat poorly drained poorly drained or very poorly drained 78 and 81 of the argialbolls are very deep 1 5 m silty alluvium and loess comprise 86 of the parent materials the dominant vegetation is grassland 64 sedges 16 or savanna 16 ninety percent of the argialboll soil series are in the fine or fine silty particle size classes 62 have a mesic soil temperature regime 36 have an aquic soil moisture regime and 64 have a smectitic soil mineral class the argialbolls have formed under modern conditions where development of a smectitic rich argillic horizon has led to reducing conditions during which fe and mn concentrate as concretions in the albic horizon that underlies the mollic epipedon

ilmenite mapping of the lunar regolith over mare australe and mare ingenii regions an optimized multisource approach based on hapke radiative transfer theory 1 we model lunar ilmenite abundances over mare australe and mare ingenii regions using a new approach we integrate lunar reconnaissance orbiter wide angle camera wac and clementine uv visible near infrared uvvis nir data to obtain a 14 band mosaic 320 2000 nm we use hapke s radiative transfer equations to compute spectra for various mixtures of orthopyroxene clinopyroxene plagioclase olivine and ilmenite with varying grain size chemistry and degree of maturity and find the closest match between the modeled spectra and the spectra of the less mature pixels optical maturity 0 2 in the 14 band mosaic we calculate a maximum stoichiometrically possible ilmenite content using clementine derived tio2 abundances and the amount of tio2 in stoichiometric ilmenite and use it as a constraint in our model we validate our methodology with lunar soil spectra of known composition our results show that the integrated wac uvvis nir data and the uvvis nir data overestimate ilmenite abundances by 8 80 wt and 7 97 wt respectively when a fixed maximum of 20 wt ilmenite is used when the maximum stoichiometrically possible ilmenite content is used as a constraint the integrated wac uvvis nir data give slightly more accurate ilmenite abundance estimation 2 87 wt than when using only uvvis nir data 3 04 wt we find ilmenite concentrations of 0 11 wt in mare australe and 0 6 wt in mare ingenii region ilmenite abundances between 4 and 7 wt are exposed in mare australe whereas ilmenite abundances between 7 and 11 wt are found on the walls of 0 6 11 8 km diameter craters within mare australe

el nino variability in simple ocean data assimilation soda 1871 2008 1 a new ocean reanalysis that covers the period from 1871 to 2008 is used to explore the time evolving characteristics of el nino the new reanalysis assimilates all available hydrographic and sea surface temperature data into a model of the global ocean forced with surface boundary conditions from an atmospheric reanalysis that also covers the period from 1871 through 2008 using traditional measures of el nino our reanalysis shows that the timing of el nino events is in agreement with sea surface temperature reconstructions but el nino in the reanalysis is stronger particularly from 1871 to 1920 a new index based on the first moment of the temperature anomaly is introduced the new index is used to characterize the strength and location of el nino events and has the advantage that it is independent of the location of el nino using the new index el nino in the reanalysis shows prominent decadal variability of strength but relatively little long term trend el nino events were strong in the last part of the 19th century and first part of the 20th century and again in the latter part of the 20th century with weak el nino events in the middle of the 20th century the location of el nino also varies considerably ranging from the western to the eastern pacific near the coast of south america however the null hypothesis that the location of el nino can be represented as a random distribution about a central longitude of about 140 w cannot be rejected

genesis of soils with an abrupt textural contrast in the united states abstract identified from the usda natural resources conservation service databases soils with an abrupt textural change atc occur in four orders alfisols mollisols ultisols aridisols 14 suborders and 31 great groups and represent nearly 1000 series in the usa more than three quarters 79 of the soils have an argillic horizon and 21 have a natric horizon an albic horizon is present in 40 of the soils more than half 58 of the soils with an atc occur in pale great groups suggesting older materials soil series with an atc occur primarily in fine 56 and clayey 14 particle size classes smectitic 49 and mixed 40 mineral classes mesic 39 and thermic 33 soil temperature classes and ustic 31 xeric 27 and aridic 21 soil moisture classes on average the texture of the eluvial and illuvial horizons varies by two classes on the soil textural triangle of the several theories accounting for the origin of soils with an atc clay illuviation from the eluvial to the illuvial horizon must be considered a major process more than halfof the soils are derived from alluvium and other stratified materials residual soils may also contain sedimentary layering which is important in the development of an atc elevenpercent of the soils have a lithologic discontinuity at the eluvial illuvial junction which may influence the development of an atc the atc in soils with an aquic soil moisture regime 13 such as the argialbolls may reflect plugging of the argillic horizon with fine clays which causes lateral subsurface flow that removes clay from the albic horizon climate may be important in the development of atc in the usa in that many of the soils are subject to extended dry periods followed by intense thunderstorms a third 34 of the soils with an atc occur in texas there are about 271 000 km2 of soils with an atc in the usa which accounts for 3 2 of the total land area

composition of the lunar highland crust from near infrared spectroscopy near infrared reflectance spectra of the lunar highlands are synthesized to obtain global information about the composition of the lunar near side crust immature exposed surfaces from small fresh craters mountains and massifs and large craters with central peaks are included in a survey of rock types across the lunar near side compositions recognized in these data include anorthosite noritic gabbric and troctolitic mineral assemblages three quarters of the areas studied that represent samples from the upper 1 2 km of lunar crust exhibit noritic compositions with different amounts of pyroxene and or brecciation alteration norites are ubiquitous across the near side and show no spatial clustering associated with any of the major basins in contrast to this noritic megaregolith of the upper crust material representing stratigraphically deeper zones 5 15 km of the lunar crust is dominated by gabbros anorthosites and troctolites with less than a quarter of the areas studied exhibiting a noritic composition the origin of the noritic megaregolith and its relation to deeper crustal material is thus somewhat of an enigma the current limited statistics for areas identified as anorthosites and troctolites are insufficient to derive global spatial distributions gabbroic areas however are notably concentrated in the western hemisphere although incomplete for a global assessment of crustal materials these data demonstrate that the lunar near side crust is clearly mineralogically heterogeneous both laterally and vertically and not well mixed below 1 2 km

the effect of skeletal mass accumulation in porites on coral sr ca and δ18o paleothermometry 1 paleotemperature estimates based on coral sr ca have not been widely accepted because the reconstructed glacial holocene shift in tropical sea surface temperature 4 6 c is larger than that indicated by foraminiferal mg ca 2 4 c we show that corals over estimate changes in sea surface temperature sst because their records are attenuated during skeletogenesis within the living tissue layer to quantify this process we microprofiled skeletal mass accumulation within the tissue layer of porites from australasian coral reefs and laboratory culturing experiments the results show that the sensitivity of the sr ca and 18o thermometers in porites will be suppressed variable and dependent on the relationship between skeletal growth rate and mass accumulation within the tissue layer our findings help explain why 18o sst sensitivities for porites range from 0 08 c to 0 22 c and are always less than the value of 0 23 c established for biogenic aragonite based on this observation we recalibrated the coral sr ca thermometer to determine a revised sensitivity of 0 084 mmol mol c after rescaling most of the published sr ca sst estimates for the indo pacific region for the last 14 000 years 7 c to 2 c relative to modern fall within the 95 confidence envelope of the foraminiferal mg ca sst records we conclude that two types of calibration scales are required for coral paleothermometry an attenuated porites specific thermometer sensitivity for studies of seasonal to interannual change in sst and importantly the rescaled 0 084 mmol mol c sr ca sensitivity for studies of 20th century trends and millennial scale changes in mean sst the calibration scaling concept will apply to the development of transfer functions for all geochemical tracers in corals

the barringer award address presented 1996 july 25 berlin germany impact experiments related to the evolution of planetary regoliths impact induced comminution of planetary surfaces is pervasive throughout the solar system and occurs on submillimeter to global scales resulting in comminution products that range from fine grained surface soils to massive polymict ejecta deposits to collisionally fragmented objects within this wide range of comminution products we define regoliths in a narrow sense as materials that were processed by repetitive impacts to dimensional scales comparable to or smaller than that of component minerals of the progenitor rock s in this paper we summarize a wide variety of impact experiments and other observations that were primarily intended to understand the evolution of regoliths on lunar basalt flows and we discuss some of their implications for asteroidal surfaces cratering experiments in both rock and noncohesive materials combined with photogeologic observations of the lunar surface demonstrate that craters 500 m in diameter contribute most to the excavation of local bedrock for subsequent processing by micrometeorites the overall excavation rate and thus growth rate of the debris layer decreases with time because the increasingly thicker fragmental layer will prevent progressively larger projectiles from reaching bedrock typical growth rates for a 5 m thick lunar soil layer are initially 3 ga ago a few mm ma and slowed to 1 mm ma at present the coarse grained crater ejecta are efficiently comminuted by collisional fragmentation processes and the mean residence time of a 1 kg rock is typically 10 ma the actual comminution of either lithic or monomineralic detritus is highly mineral specific with feldspar and mesostasis comminuting preferentially over pyroxene and olivine thus resulting in mechanically fractionated fines especially at grain sizes 20 m such fractionated fines also participate preferentially in the shock melting of lunar soils thus giving rise to agglutinate melts as a consequence agglutinate melts are systematically enriched in feldspar components relative to the bulk composition of their respective host soil s compositionally homogeneous impact derived glass beads in lunar soils seem to result from micrometeorite impacts on rock surfaces reflecting lithic regolith components and associated mineral mixtures cumulatively experimental and observational evidence from lunar mare soils suggests that regoliths derive substantially from the comminution of local bedrock the addition of foreign exotic components is not necessary to explain the modal and chemical compositions of diverse grain size fractions from typical lunar soils regoliths on asteroids are qualitatively different from those of the moon the modest impact velocities in the asteroid belt some 5 km s 1 are barely sufficient to produce impact melts also substantially more crater mass is being displaced on low gravity asteroids compared to the moon collisional processing of surface boulders should therefore be more prominent in producing comminuted asteroid surfaces these processes combine into asteroidal surface deposits that have suffered modest levels of shock metamorphism compared to the moon impact melting does not seem to be a significant process under these conditions however the role of cometary particles encountering asteroid surfaces at presumably higher velocities has not been addressed in the past unfortunately the asteroidal surface processes that seemingly modify the spectral properties of ordinary chondrites to match telescopically obtained spectra of s type asteroids remain poorly understood at present despite the extensive experimental and theoretical insights summarized in this report and our fairly mature understanding of lunar surface processes and regolith evolution

genesis of two planosols in the massif central france abstract two planosols developed on gravelly quaternary sediments of the river allier in the limagne rift valley massif central france were studied parent material contained in addition to a granitic component large amounts of volcanic particles morphological chemical mineralogical and physical properties of both profiles were investigated to indicate some of the changes which have taken place during pedogenesis both profiles were characterized by pronounced textural contrasts between sandy a and e horizons and clayey b horizons soil formation rather than a transient depositional environment is thought to be responsible for this marked textural change clear dissolution features of all mineral grains except quartz and increasing amounts of volcanic fragments with depth suggested weathering increasing ratios of mobile basic cations to tio 2 with increasing depth corroborated this observation the presence of non laminated isotropic and anisotropic limpid clay coatings were also evidence of in situ mineral weathering in both profiles kaolinite predominated as clay mineral and increased towards the surface micromorphological observations of microlaminated dusty and impure clay coatings in b horizons of both profiles were clear signs of clay illuviation bulk densities were high in lower e horizons and upper b horizons field observations and micromorphological data showed clear signs of periglacial features the combination of pedogenic and periglacial processes has apparently lead to a considerable compaction abundant cemented iron and manganese features predominantly occurring in e horizons suggested surface water gleying micromorphological observations of illuviation coatings in b horizons and of fine material in a and e horizons demonstrated grainy aspects suggesting ferrolysis