mineralogical characterization of some basaltic asteroids in the neighborhood of 4 vesta first results abstract we present reflectance spectra of 19 v type asteroids obtained at the 3 6 m telescopio nazionale galileo covering 0 8 to 2 5 m for 8 of these asteroids we obtained also visible spectra in the same observational run the range from 0 8 to 2 5 m encompassing the 1 and 2 m pyroxene features allows a precise mineralogical characterization of these asteroids the obtained data suggests the possible coexistence of distinct mineralogical groups among the v type asteroids either probing different layers of 4 vesta or coming from different bodies no clear correlation was found between mineralogies and the objects being or not member of the vesta dynamical family

a new data reduction approach for the clementine nir data set application to aristillus aristarchus and kepler the clementine spacecraft launched in january 1994 has performed a nearly global surface mapping of the moon in eleven broad spectral bands at a resolution of 200 m the uv visible uv vis camera performed observations in five bands ranging from 0 415 to 1 0 m while the near infrared camera nir acquired data in six spectral bands ranging from 1 1 to 2 78 m uv vis images are calibrated to 4 the calibrated nir data set is yet to be finalized due to instrumental problems independently of the calibration effort for the full data set which is under the responsibility of the pi team we present here the first results of a heuristic approach to extract mineralogical information from raw images in regions of particular interest we processed images of craters aristillus aristarchus and kepler we computed band ratios using 0 75 0 9 0 95 1 0 1 1 1 25 1 5 and 2 0 m images to map the compositional heterogeneity and to discriminate between pyroxene olivine or feldspar rich areas absolute reflectance spectra have been derived using telescopic spectra as ground truth high orthopyroxene and clinopyroxene contents have been detected and spatially mapped on aristillus our results are in good agreement with previous studies in the case of aristarchus and show additional details due to the improved registration two regions exhibit spectra consistent with a high proportion of olivine with 25 pyroxene the rim of kepler exhibits a strong feature at 2 m correlated with the 1 m feature suggesting either a high orthopyroxene content or a very immature soil our method could be of interest for further investigations of the lunar surface using clementine nir data

the nature of crater rays the copernicus example crater rays are formed during a cratering event as target material is ballistically ejected to distances of many crater radii forming narrow generally high albedo approximately linear features extending outward from the crater the nature of crater rays was examined for the lunar crater copernicus using new information on the composition of surface material from near ir reflectance measurements surface roughness from radar backscatter measurements and photogeologic data from available images part of the data analysis included use of mixing models to quantify the mixing systematics observed between primary ejecta and local substrate of the ray on the basis of compositional parameters from reflectance spectra primary material from copernicus can be detected in the surface material of rays in decreasing amounts with increasing radial distance e g 20 25 primary ejecta at six crater radii for distances greater than three crater radii the proportion of local material to primary ejecta observed from these compositional reflectance data is approximately equal to that predicted by previous laboratory and ballistic studies of craters within three crater radii the compositional data indicate a higher proportion of primary ejecta than predicted for extended areas along the ray that do not contain large secondary craters the primary ejecta is intimately mixed on the granular scale with local material throughout the regolith the relatively high albedo of the rays of copernicus is due to the feldspathic composition highland of the primary ejecta in rays emplaced on a mare substrate immature local substrate is only observed in copernicus s ray at large unmantied secondary craters or other areas with sufficient topographic slope to prevent the accumulation of mature soils crater rays are filamentous generally high albedo features that emanate nearly radially from young impact structures rays are narrow in relation to the crater radius extend distally for many crater radii and constitute a distinctive albedo feature around some of the largest and freshest lunar craters visible from earth synoptic views of ray systems figure la give the strong impression that the rays comprise bright material that has been excavated from the crater cavity and been emplaced beyond the continuous ejecta deposit if this visual impression is correct then the process that forms crater rays represents a significant mechanism for the lateral transport of primary material to great distances from its point of origin and particularly for craters larger than a let tens of kilometers in diameter constitutes a fundamental process for the regional mixing of crustal materials earth based telescopic images of the moon allowed the first studies and descriptions of rays and ray systems shoemaker 1962 described the arcuate and loop shaped streaks of the copernicus ray systems and showed that these patterns could be locally resolved into individual en echelon feather shaped elements 15 20 km in length with their long axes oriented approximately radially to the crater he noted the presence of elongate depressions or gouges in the ray system ranking in diameter from 8 km down to the limits of resolution and generally located at the proximal ends of the individual ray elements shoemaker observed that some of the gouges were

gnss r nonlocal sea state dependencies model and empirical verification global navigation satellite system reflectometry gnss r is an active bistatic remote sensing technique operating at l band frequencies gnss r signals scattered from a rough ocean surface are known to interact with longer surface waves than traditional scatterometery and altimetry signals a revised forward model for gnss r measurements is presented which assumes an ocean surface wave spectrum that is forced by other sources than just the local near surface winds the model is motivated by recent spaceborne gnss r observations that indicate a strong scattering dependence on significant wave height even after controlling for local wind speed this behavior is not well represented by the most commonly used gnss r scattering model which features a one to one relationship between wind speed and the mean square slope of the ocean surface the revised forward model incorporates a third generation wave model that is skillful at representing long waves an anchored spectral tail model and a gnss r electromagnetic scattering model in comparisons with the spaceborne measurements the new model is much better able to reproduce the empirical behavior

importance of peakedness in sea surface slope measurements and applications we recall the simple statistical concept that non gaussian distribution peakedness results from the compounding of random processes this idea is applied to observations and analysis of sea surface slopes as inferred using optical and microwave scattering measurements our study emphasizes the importance of identifying and quantifying the distribution variance and kurtosis from observations data are shown to indicate consistently non gaussian peakedness to indicate the need to report at least two parameters in an even order analysis and to indicate near equivalence between radar and optical data physical interpretation for observed infrequent steep slopes is given via compounding statistical processes where normally distributed short scale waves are modulated because of random fluctuations mainly associated with the underlying long wave field implications of non gaussian peakedness are provided for altimeter backscatter theory and for modeling wave breaking probability

metal silicate mixtures spectral properties and applications to asteroid taxonomy the reflectance spectra of combinations of olivine orthopyroxene and iron meteorite metal show systematic variations in spectral properties which can be used to constrain many of the physical and chemical properties of the assemblages the presence of metal most noticeably affects band area ratios peak peak and peak minimum reflectance ratios and band widths these parameters are also affected to varying degrees by the abundance and grain size of the metal and silicates and the composition of the silicates band width and band areas are useful for determining metal abundance in olivine metal and orthopyroxene metal assemblages respectively mafic silicate grain size variations are best determined using band depth criteria band centers are most useful for determining mafic silicate composition analysis of the reflectance spectrum of the s class asteroid 8 flora on the basis of these spectral parameters indicates a surface composed of approximately 50 wt metal 40 wt olivine fa 35 10 10 wt orthopyroxene fs 30 25 35 and perhaps a few weight percent of clinopyroxene a substantial amount of the surface seems to consist of a fine grained 45 m size component analysis of the reflectance spectrum of the a class asteroid 446 aeternitas suggests a surface assemblage of approximately 35 wt metal 55 wt olivine fa 20 10 7 wt clinopyroxene fs 17 and 3 wt orthopyroxene fs 45 a substantial fine grained 45 m size surface component is also indicated for this asteroid

new results and implications for lunar crustal iron distribution using sensor data fusion techniques remote measurements of the moon have provided iron maps and thus essential constraints for models of lunar crustal formation and mare basalt petrogenesis a bulk crustal iron map was produced for the equatorial region from apollo gamma ray agr spectrometer measurements and a global iron variation map from recent clementine spectral reflectance csr measurements both iron maps show bimodal distribution but have significantly different peak values and variations in this paper csr data have been recalibrated to pyroxene in lunar landing site soils a residual iron map is derived from the difference between agr bulk and recalibrated csr pyroxene iron abundances the most likely interpretation is that the residual represents ferrous iron in olivine this residual iron is anticorrelated to basin age with older basins containing less olivine suggesting segregation of basin basalt sources from a progressively fractionating underlying source region at the time of basin formation results presented here provide a quantitative basis for 1 establishing the relationship between direct geochemical gamma ray x ray and mineralogical near ir remote sensing data sets using sensor data fusion techniques to allow 2 simultaneous determination of elemental and mineralogical component distribution on remote targets and 3 meaningful interpretation of orbital and ground based spectral reflectance measurements when calibrated data from the lunar prospector mission are available mapping of bulk crustal iron and iron bearing soil components will be possible for the entire moon similar analyses for data from the near earth asteroid rendezvous near mission to asteroid 433 eros will constrain models of asteroid formation

close range ground based hyperspectral imaging for mining applications at various scales review and case studies abstract detailed mapping of mineral phases at centimeter scale can be useful for geological investigation including resource exploration this work reviews case histories of ground based close range hyperspectral imaging for mining applications studies of various economic deposits are discussed as well as techniques used for data correction integration with other datasets and validation of spectral mapping results using geochemical techniques machine learning algorithms suggested for automation of the mining workflow are reviewed as well as systems for environmental monitoring such as gas leak detection three new case studies that use a ground based hyperspectral scanning system with sensors collecting data in the visible near infrared and short wave infrared portions of the electromagnetic spectrum in active and abandoned mines are presented vertical exposures in a carlin style sediment hosted gold deposit an active cu au mo mine and an active asphalt quarry are studied to produce images that delineate the extent of alteration minerals at centimeter scale to demonstrate an efficient method of outcrop characterization which increases understanding of petrogenesis for mining applications in the carlin style gold deposit clay iron oxide carbonate and jarosite minerals were mapped in the copper porphyry deposit different phases of alteration are delineated some of which correspond to greater occurrence of ore deposits a limestone quarry was also imaged which contains bitumen deposits used for road paving aggregate review of current literature suggests use of this technology for automation of mining activities thus reducing physical risk for workers in evaluating vertical mine faces

visible and near infrared reflectance spectroscopy of pyroxene bearing rocks new constraints for understanding planetary surface compositions 1 laboratory visible and near infrared reflectance spectra of solid rock slabs mineral separates and systematic mixtures were simultaneously investigated we apply an empirical approach to evaluate spectra in order to achieve qualitative and quantitative information we use cumulates mostly norites leuconorites melanorites and anorthosites belonging to the bjerkreim sokndal layered intrusion a sequence of genetically related rocks with simple textures laboratory spectra are measured on slightly polished rock slabs in the 350 to 2500 nm interval and directional hemispherical reflectance geometry composition is determined using traditional techniques other than reflectance spectroscopy we find that 1 band minima measured on rock spectra are strongly influenced by the concurrent effects due to modal abundance of the spectroscopically active mineral and mineral chemistry 2 band depths can be used for semiquantitative analyses limited to the set of rocks investigated 3 the spectral parameters derived from powdered pyroxene are in agreement with previously published calibrations 4 the mineral mixture systematics can be reasonably considered as linear when pyroxene is mixed with neutral components and 5 the empirical evaluation of solid rock surface spectra needs further insights to give a great improvement to planetary researches in addition genetic sequences of rocks should be investigated in detail to help the geological interpretation of planetary evolution therefore more laboratory and analytical studies are required in order to understand the influence of composition and petrographic textures on the spectral analysis

exogenic olivine on vesta from dawn framing camera color data abstract in this paper we present the results of a global survey of olivine rich lithologies on 4 vesta we investigated dawn framing camera fc high altitude mapping orbit hamo color cubes 60 m pixel resolution by using a method described in thangjam et al thangjam g nathues a mengel k hoffmann m schafer m reddy v cloutis e a christensen u sierks h le corre l vincent j b russell c t 2014b meteorit planet sci arxiv 1408 4687 astro ph ep in total we identified 15 impact craters exhibiting olivine rich 40 wt ol outcrops on their inner walls some showing olivine rich material also in their ejecta and floors olivine rich sites are concentrated in the bellicia arruntia and pomponia region on vesta s northern hemisphere from our multi color and stratigraphic analysis we conclude that most if not all of the olivine rich material identified is of exogenic origin i e remnants of a or and s type projectiles the olivine rich lithologies in the north are possibly ejecta of the 90 km diameter albana crater we cannot draw a final conclusion on their relative stratigraphic succession but it seems that the dark material nathues a hoffmann m cloutis e a schafer m reddy v christensen u sierks h thangjam g s le corre l mengel k vincent j b russell c t prettyman t schmedemann n kneissl t raymond c gutierrez marques p hall i buttner i 2014b icarus 239 222 237 and the olivine rich lithologies are of a similar age the origin of some potential olivine rich sites in the rheasilvia basin and at crater portia are ambiguous i e these are either of endogenic or exogenic origin however the small number and size of these sites led us to conclude that olivine rich mantle material containing more than 40 wt of olivine is basically absent on the present surface of vesta in combination with recent impact models of veneneia and rheasilvia clenet h jutzi m barrat j a gillet ph 2014 lunar planet sci 45 1349 jutzi m asphaug e gillet p barrat j a benz w 2013 nature 494 207 210 which predict an excavation depth of up to 80 km we are confident that the crust mantle depth is significantly deeper than predicted by most evolution models 30 km mittlefehldt d w 2014 asteroid 4 vesta a fully differentiated dwarf planet nasa technical reports server 20140004857 pdf or alternatively the olivine content of the upper mantle is lower than our detection limit which would lead to the conclusion that vesta s parent material was already depleted in olivine compared to ci meteorites

alteration of hydrovolcanic basaltic ash observations with visible and near infrared spectrometry ash of basaltic composition that is produced by hydrovolcanic activity occurs frequently on earth and may be much more widespread on mars altered basaltic tephras from tuff rings and tuff cones across the basin and range were examined using visible and near infrared vis ir reflectance spectrometry and a variety of other techniques it was found that vis ir spectrometry is sensitive to subtle changes in the hydration and oxidation state of these tephras hydration produces an increase in overall reflectance with gradual development of water and hydroxyl absorptions at 1 4 m and 1 9 m the oxidation of basaltic tephras can be observed spectrally through changes in the position and slope of the fe3 o2 charge transfer edge inflections on that edge due to ferric oxide minerals and changes in the position and depth of the 1 m iron crystal field band significantly in the tuffs examined ferrous and ferric iron minerals produce one composite absorption feature rather than two resolvable bands different styles of alteration were noted between thinly bedded tuff ring deposits emplaced by high energy largely dry pyroclastic surge and massively bedded tuff cone deposits emplaced by wetter lower energy pyroclastic flow the former class of tephras become hydrated and only moderately oxidized with some limited development of dioctahedral smectite clay minerals and minimal palagonitization the latter class of tephras are highly palagonitized which implies a high degree of hydration and oxidation in fact in the most highly altered tephras all the fe2 that is initially in the volcanic glass is converted to fe3 within nanophase and bulk ferric oxide phases in the palagonite there is also more extensive development in the tuff cone beds of zeolite and phyllosilicate minerals the differences in reflectance spectra of altered basaltic tephras can be traced back to initial differences in the water magma ratio extant at the volcanic vent thus vis ir spectrometry holds the potential to be used as a tool for investigations into the volcanic history and paleoclimate of volcanic terrains

thermal alteration a possible reason for the inconsistency between omega crism and tes detections of phyllosilicates on mars previous laboratory analyses have shown that high temperatures can modify the crystal structures of some phyllosilicates in such a way that their spectroscopic signatures appear different from various wavelength perspectives this may be the case in the nili fossae region of mars where our analyses indicate that thermally altered 400 c fe rich smectites might be possible mineral analogs to the phyllosilicate bearing units in addition to mineral assemblages formed by fe mg smectite and amorphous weathering products we suggest that thermal alteration of phyllosilicates induced by impact shock or other heat sources might be a widespread process throughout martian history the mixing of altered and unaltered phyllosilicates might be partially responsible for the apparent disconnect between vnir and tir observations of fe mg smectite bearing surfaces on mars

mineralogic mapping of the av 9 numisia quadrangle of vesta abstract in this manuscript we present the mineralogic mapping of the av 9 numisia quadrangle of vesta using the most up to date data from the nasa dawn mission this quadrangle is located in vesta s equatorial zone 22 south to 22 north 218 to 288 east in claudia coordinate system and takes its name from the impact crater numisia the main feature which dominates the quadrangle is the vestalia terra plateau a topographic high about 10 km above the surrounding areas to the south this region fades into the rheasilvia basin while to the north it is bounded by the steep scarp of postumia basin the visible and infrared mapping spectrometer vir onboard nasa dawn provided the main data source for this work at an unprecedented level of spatial and spectral resolution in particular we are using spectral parameters to synthesize characteristics of the whole spectra into a single value pyroxene related spectral parameters allow for the detection of lower crust or mantle material diogenites and upper crust material eucrites in the study area the combined analysis of albedo from the framing camera the geologic map and the spectroscopic data offer an interesting opportunity to understand better the surface features of this region of vesta and their evolution numisia cornelia fabia teia and drusilla are the main craters in the study area rich in bright and dark material outcrops pitted terrains and oh rich materials using the spectral parameters we demonstrate that the internal composition of vestalia terra is mainly diogenite rich howardite as shown by materials excavated by cornelia and fabia and the composition of the slope north of vestalia terra this agrees with the strong positive bouguer anomaly observed in the area indicating a higher density of these features in relation to the surrounding areas besides the recently published works based on gravimetric modeling and geologic interpretation the mineralogic mapping presented herein gives an additional contribution in order to depict a more complete geologic history of the numisia quadrangle of vesta

discrimination of active and inactive sand from remote sensing kelso dunes mojave desert california abstract landsat tm images field data and laboratory reflectance spectra were examined for the kelso dunes mojave desert california to assess the use of visible and near infrared vnir remote sensing data to discriminate aeolian sand populations on the basis of spectral brightness results show that areas of inactive sand have a larger percentage of dark fine grained materials compared to those composed of active sand ehich contain less dark fines and a higher percentage of quartz sand size grains both areas are spectrally distinct in the vnir suggesting that vnir spectral data can be used to discriminate active and inactive sand populations in the mojave desert analysis of laboratory spectra was complicated by the presence of magnetite in the active sands which decreases their laboratory reflectance values to those of inactive sands for this application comparison of tm and laboratory spectra suggests that less than 35 vegetation cover does not influence the tm spectra

spectral evidence for the mineralogy of high albedo soils and dust on mars because of the lack of direct mineralogic data available for mars spectral remote sensing techniques and in particular earth based reflectance spectroscopy remain the primary source of this information presented here are laboratory observations which further constrain the mineralogy and origin of the high albedo soils and dust earth based observations show the reflectance spectra of classical bright regions to be fairly uniform with a strong fe3 o2 charge transfer absorption edge extending from the near uv through the visible this absorption is relatively smooth unlike those observed for crystalline ferric oxides which have superimposed fe3 crystal field bands dilution of ferric oxide with a spectrally more neutral medium montmorillonite weakens the charge transfer and crystal field absorptions together and does not serve to make the ferric oxide spectrum more mars like smoother nontronite ferric iron bearing smectite clay was also investigated for spectral agreement with telescopic observations pure nontronite has fe3 absorptions analogous to but different from ferric oxides as in the previous case the absorptions are very distinct and inappropriate for mars admixture of neither montmorillonite nor ferric oxide serves to improve the nontronite spectrum the conclusion is that nontronite is not a major component of martian soils although the presence of other iron poor clays cannot be totally excluded based on currently available observational data the best spectral analogs known for high albedo soil and dust are a specific type of palagonite from hawaii x ray amorphous weathering products of mafic volcanic glass the indication is therefore that ferric iron on mars is likely to occur in poorly defined crystallo graphic sites such as found in these amorphous materials these materials form slowly under semiarid conditions at ambient temperature even low temperature hydrothermal alteration of glass might provide enough ion mobility to favor some formation of crystalline clays over amorphous gels and may therefore not be the primary mechanism responsible for soil formation on mars the amorphous hawaiian soils exist metastably for thousands of years on earth similar materials on mars would be expected to survive considerably longer under the present cold and dry climatic conditions

bulk mineralogy of the ne syrtis and jezero crater regions of mars derived through thermal infrared spectral analyses abstract we investigated the area to the northwest of the isidis impact basin hereby referred to as nw isidis using thermal infrared emission datasets to characterize and quantify bulk surface mineralogy throughout this region this area is home to jezero crater and the watershed associated with its two deltaic deposits in addition to ne syrtis and the strong and diverse visible near infrared spectral signatures observed in well exposed stratigraphic sections the spectral signatures throughout this region show a diversity of primary and secondary surface mineralogies including olivine pyroxene smectite clays sulfates and carbonates while previous thermal infrared investigations have sought to characterize individual mineral groups within this region none have systematically assessed bulk surface mineralogy and related these observations to visible near infrared studies we utilize an iterative spectral unmixing method to statistically evaluate our linear thermal infrared spectral unmixing models to derive surface mineralogy all relevant primary and secondary phases identified in visible near infrared studies are included in the unmixing models and their modeled spectral contributions are discussed in detail while the stratigraphy and compositional diversity observed in visible near infrared spectra are much better exposed and more diverse than most other regions of mars our thermal infrared analyses suggest the dominance of basaltic compositions with less observed variability in the amount and diversity of alteration phases these results help to constrain the mineralogical context of these previously reported visible near infrared spectral identifications the results are also discussed in the context of future in situ investigations as the nw isidis region has long been promoted as a region of paleoenvironmental interest on mars

three basaltic earth approaching asteroids and the source of the basaltic meteorites we report five color photometry near infrared spectra 0 8 2 5 m and thermal observations of the earth approaching asteroids 3551 1983 rd 3908 1980 pa and 4055 1985 do2 we derive their diameters as 1 2 1 0 and 3 4 km respectively apart from greater absorption band depths the spectra of these three small asteroids are nearly identical to that of vesta which is known to have a differentiated basaltic surface the deeper pyroxene bands 0 9 and 1 9 m relative to vesta are consistent with more pyroxene rich surfaces larger mineral grain sizes in their optically immature regoliths more bare rock surfaces or all of these factors these small earth approaching asteroids have similar orbits with perihelia near earth s orbit in july august they are probably not fragments of vesta but may be fragments of one or more vesta like parent bodies the spectra of vesta and the three earth approachers resemble those of the basaltic meteorites i e eucrites howardites and diogenites hed meteorites we find that hed fall times show a weak peak in july august suggesting that 3551 3908 and 4055 may be fragments of the source bodies of the hed meteorites or perhaps of a single common hed parent body the kilometer size asteroids have regoliths with significant insulating properties but these regoliths differ from that of the moon in that the particle sizes are larger than on the moon and lunar like glasses and agglutinates are largely absent the causes of these differences are related to impact velocities impact shaking and debris retention on small bodies differentiated basalt or mantle like asteroids may have impacted earth and left discontinuities in the geologic climatic record without leaving the chemical signatures associated with the k t boundary event

reflectance spectroscopy of plagioclase dominated mineral mixtures implications for characterizing lunar anorthosites remotely anorthositic rocks dominate the moon s upper crust as remnants of the lunar magma ocean lmo small variations in the mineralogy of these rocks may hold key information about the homogeneity of lmo composition and solidification processes orbital near infrared nir sensors are sensitive to mineralogy but technologic advances have only recently enabled detection of the plagioclase component in crustal rocks based on an absorption band centered near 1250 nm anorthosites occupy a unique mineralogic range that is well suited for nir studies the highly transparent component plagioclase is present in high abundances while the spectrally dominant mafic or oxide minerals are present in only minor abundance as a result spectra of anorthosites are more likely than many other rock types to contain visually discernable signatures from more than one mineral component facilitating their identification and characterization in nir data in support of new nir measurements for the moon we present laboratory spectral analyses of well controlled plagioclase dominated mineral mixtures we focus on the spectral effects of varying mafic and oxide composition and abundance in mixtures with a common plagioclase end member the results demonstrate that plagioclase can be a significant contributor to reflectance spectra when strongly absorbing minerals are present in low abundance we show that the contribution of plagioclase is more pronounced in mixtures with pyroxenes and certain spinels but more easily masked in mixtures containing small amounts of olivine differences in minor mineral composition are clearly expressed in bulk spectra modeling of mixtures using a hapke nonlinear approach accurately estimates mineral abundances in laboratory spectra to within 5 vol for mixtures with 90 vol plagioclase together these results imply that not only should orbital nir data sets be able to discern the presence of plagioclase in anorthositic crustal exposures but also that detailed information about anorthosite mineral assemblages can be reliably accessed in reflectance spectra

correction of the sea state impact in the l band brightness temperature by means of delay doppler maps of global navigation satellite signals reflected over the sea surface this paper presents an efficient procedure based on 2 d convolutions to obtain delay doppler maps ddms of global navigation satellite signals reflected gnss r over the sea surface and collected by a spaceborne receiver two ddm derived observables area and volume are proposed to link the sea state induced brightness temperature to the measured normalized ddm finally the requirements to use global positioning system reflectometry to accurately correct for the sea state impact on the l band brightness temperature quantization levels decimation truncation and noise impact are analyzed in view of its implementation in the passive advanced unit instrument of the spanish earth observation satellite seosat ingenio project

variability of the oceanic surface and subsurface layers in the warm pool associated with the atmospheric northward propagating intraseasonal variability abstract the variability of the oceanic surface and subsurface layers associated with the northward propagating intraseasonal variability isv in northern summer were examined in the western north pacific wnp warm pool using satellite and in situ observation data analyses of satellite observation data revealed that the sst decreases when a convection maximum of the isv passes the sea surface temperature sst difference maximum minus minimum was about 1 5 to 2 0 c in the southern part of the warm pool the sst abruptly decreased just before the convection maximum examination of argo float data revealed that the temperature profile shifted upward before the convection peak during this period the mixed layer depth mld did not largely change despite strong sea surface wind and diabatic cooling according to the sea surface wind data a large cyclonic wind stress curl was identified just north of the convection center associated with a small coriolis parameter the upward ekman pumping appears to contribute to the maintenance of a shallow mixed layer and the abrupt cooling of sst after the rapid cooling the sst was almost constant although the mixed layer was deepened however in the northern part where the ekman pumping was relatively small the sst decreased in accordance with the increase of mld throughout the cooling period it was suggested that the air sea coupling in the off equatorial region differs from that on the equator

spectral analysis of the bright materials on the asteroid vesta vesta spectra have prominent near infrared absorption bands characteristic of pyroxenes indicating a direct link to the howardite eucrite and diogenite meteorites many localized dark and bright materials are present on vesta s surface here we focus on the bright material bm units to determine their spectral properties their origin the presence of mineralogical phases different from pyroxenes and whether different bright units share a common lithology vir the visible and infrared spectrometer onboard dawn allows us to first do a detailed analysis of the spectral properties of a large number of bright material units on vesta including examples of the different morphological classes the spectral parameters used are band centers band depths and band area ratio bar for the pyroxene bands at 0 9 and 1 9 m the mineralogies of most bright regions are consistent with those of the howardite eucrite and diogenite meteorites typical of vesta s surface we find that bright material units exhibit the full range of hed pyroxene composition from eucrites to diogenites large part of the bright materials are eucrite rich according with the vesta s mineralogy in most cases the bright materials have the same mineralogy of the surrounding terrain but have larger band depth values the band depths can be related to the abundance of the absorbing minerals the abundance of fe2 grain size and or to the abundance of opaque materials we found a positive correlation between albedo and band depth which suggests that the grain size is not the main factor responsible for the higher albedo the analysis of the band parameters indicates that most of the bright materials excluding the few olivine rich units represent fresh uncontaminated vestan pyroxenes from a variety of lithologies exposed from beneath the surface by impacts

meridional sst gradient in the western north pacific warm pool associated with typhoon generation 1 we examined the sea surface temperature sst distribution in the western north pacific warm pool when a typhoon is generated in northern summer analyzing satellite observation data revealed higher lower sst north south of the typhoon as a result the meridional sst gradient became especially steep and the sst was not homogeneously high when a typhoon is generated in situ observation data in the oceanic surface layer suggested that the low sst was caused by vertical mixing related to the strong southwesterly monsoon in contrast the hot spots north of the typhoon were associated with weak sea surface wind and vertical mixing according to satellite observation the maxima of surface heat flux and water vapor shifted northward corresponding to the high sst they may produce an asymmetry of the thermodynamic structure of a typhoon

sediment mineralogy based on visible and near infrared reflectance spectroscopy visible and near infrared spectroscopy vnis can be used to measure reflectance spectra wavelength 350 2500 nm for sediment cores and samples a local ground truth cali bration of spectral features to mineral percentages is calculated by measuring reflectance spectra for a suite of samples of known mineralogy this approach has been tested on powders core plugs and split cores and we conclude that it works well on all three unless pore water is present initial vnis studies have concentrated on determination of relative proportions of carbonate opal smectite and illite in equatorial pacific sediments shipboard vnis based determination of these four components was demonstrated on ocean drilling program leg 199 rock colour is one of our oldest clues to com position and spectroscopy instruments now surpass the eye in providing quantitative compo sitional information the experimental technique is straightforward and non intrusive simply illu minate a rock surface record the spectrum of reflected light and extract any spectral responses that are sensitive to mineralogy reflectance spectroscopy can be used on powders core plugs and split cores and measurements take only seconds these advantages make the tech nique particularly attractive for depleted inter vals of core e g many basalts and for climate proxies requiring thousands of high resolution measurements

terrestrial analogues of the surface rocks of mars the pathways of chemical weathering processes on earth and the virtual absence of them on the moon are well characterized because we have direct access to samples of primary igneous rocks their upper mantle sources and derivative sedimentary rocks and soil forming the regolith tracing chemical changes on the surface of mars however is more difficult because of limited access to samples from mars terrestrial rocks and minerals are continually being sought which might serve as analogues for martian materials evidence presented here suggests that hisingerite iddingsite and several ferric sulphate minerals derived from deuteric alteration of iron rich basalts may provide clues to the evolutionary history of the surface of mars

sequential processing of gnss r delay doppler maps to estimate the ocean surface wind field spaceborne global navigation satellite system reflectometry gnss r measurements of ocean winds present a challenge because the surface wind speed cannot be assumed homogeneous over the large glistening zone observable from orbit the 25 km resolution requirement of the cyclone gnss cygnss mission limits wind speed retrievals to using only a small fraction of the delay doppler map ddm near the specular point this paper presents a new method to invert a larger portion of the ddm and estimate the wind field within a swath defined by the maximum delay an extended kalman filter ekf is applied to combine a series of ddms and estimates the wind speed on a uniformly gridded ocean surface exploiting the large overlap between sequential looks wind retrievals at the specular point using simulated data generated using wind fields from two hurricanes danielle and earl 2010 were found to meet the cygnss measurement requirements 2 m s for u 20 m s and perform better than a typical single point observable wind retrievals were also found to meet these requirements below 20 m s within a 90 km swath and meet them for hurricane force winds 17 times 11 ddm demonstrating benefits of sequential processing within a limited data budget delay doppler ambiguities introduced noticeable artifacts in circumstances where the wind varies asymmetrically within the observed 90 times 90 km surface area but did not appear to affect specular point wind retrievals

mineralogical petrological characterization of near earth asteroids studies of near earth asteroids are aimed at determining their dynamical and structural history the mineralogy and petrology of 17 near earth asteroids are characterized using reflectance spectroscopy with ground based telescopes as one method to address their major issues implications for the origin and evolution are discussed in a separate paper assuming the surfaces are composed of cosmically abundant materials the presence of certain mineralogical species can be determined from diagnostic absorption features and spectral characteristics which have been studied under known laboratory conditions and understood in terms of crystal field theory with one possible exception the surface composition of near earth asteroids consists of common rock forming minerals such as olivine pyroxene and phyllosilicates opaque components are present but cannot be mineralogically identified with existing experimental data the spectrum of 2201 oljato cannot be interpreted in terms of common rock forming minerals this spectrum was examined for cometary features because its high orbital eccentricity suggests a possible relation to comets no common cometary features are identified in its spectrum the predominance of mafic silicate absorption features in spectra of near earth asteroids compared to the majority of main belt asteroids may be a primary compositional feature or may be the signature of relatively fresher asteroid material

assessing martian bedrock mineralogy through windows in the dust using near infrared and thermal infrared remote sensing abstract much of mars surface is mantled by bright dust which masks the spectral features used to interpret the mineralogy of the underlying bedrock despite the wealth of near infrared nir and thermal infrared tir data returned from orbiting spacecraft in recent decades the detailed bedrock composition of approximately half of the martian surface remains relatively unknown due to dust cover to address this issue and to help gain a better understanding of the bedrock mineralogy in dusty regions dust cover index results from the mars global surveyor thermal emission spectrometer tes and analysis of images from the mars reconnaissance orbiter mars color imager marci were used to identify 63 small localized areas within the classical bright dusty regions of arabia terra elysium planitia and tharsis montes as potential windows through the dust that is areas where the dust cover is thin enough to permit infrared remote sensing of the underlying materials the mineralogy of each candidate window was inferred using spectra from the mars express observatoire pour la mineralogie l eau les glaces et l activite omega nir spectrometer and where possible tes twelve areas of interest returned spectra that are consistent with mineral species expected to be present at the regional scale such as high and low calcium pyroxene olivine and iron bearing glass distribution maps were created using previously defined index parameters for each species present within an area high quality tes spectra if present within an area of interest were deconvolved to estimate modal mineralogy and to support nir interpretations omega data from arabia terra and elysium planitia are largely similar and indicate the presence of high calcium pyroxene with significant contributions of glass and olivine while tes data suggest an intermediate between the established compositions of the southern highlands and syrtis major limited data from tharsis are consistent with low calcium pyroxene mixed with lesser amounts of glass and high calcium pyroxene tes data from southern tharsis correlate well with the previously inferred compositions of the aonium and mare sirenum highlands immediately to the south of particular note is the detection of iron bearing glass as a significant component of all three analyzed regions especially in tharsis overall the underlying compositions of the classically dust covered regions of mars appear consistent with the compositions of adjacent and other low albedo not dust covered regions of the planet identified in previous studies with the noted contribution from iron bearing glass

the regolith properties of the chang e 5 landing region and the ground drilling experiments using lunar regolith simulants abstract the chang e 5 ce 5 mission is china s first lunar sample return mission the rumker region in northern oceanus procellarum was selected as the landing area ce 5 will automatically sample 2 kg of lunar samples from the surface and subsurface previous studies focused more on the geological background of the landing region however the lunar regolith properties also have a significant influence on the mission especially drilling and thus should be studied and constrained in this research we analyzed the lunar regolith properties of the ce 5 landing region first using remote sensing measurements the western maria and eastern maria in the landing region are both covered by very low ti to low ti basaltic regolith the western mare regolith with longer exposure to space weathering is more mature finer and thicker than the eastern mare regolith cug series lunar regolith simulants were then produced based on our analysis physically and chemically of the regolith properties of ce 5 landing region and compared to apollo soils finally the lunar simulants were used to perform ground drilling experiments to support the drilling of the ce 5 mission in a fixed rotation speed 120 rpm feed speed 120 mm min and total drilling depth 1 m 274 291 and 346 g of lunar simulants were cored on simulants mixture 1 mixture 2 and mixture 3 respectively our experiments suggest that it is easier to drill and core finer and looser lunar regolith in this case the western mare regolith is easier for drilling than the eastern mare regolith however samples from the eastern young maria em3 em4 are scientifically more meaningful we propose that landing on and drilling in a smooth and mature area in unit em4 should be the highest priority for the ce 5 mission this can be accomplished by careful landing site selection precise landing and optimized drilling control

end member identification and spectral mixture analysis of crism hyperspectral data a case study on southwest melas chasma mars we present spectral unmixing results over the southwest melas chasma region where a variety of hydrated minerals were identified we use the disort radiative transfer model to simultaneously model mars atmospheric gases aerosols and surface scattering and retrieve the single scattering albedos ssas modeled by the hapke bidirectional scattering function from crism data we employ a spectral unmixing algorithm to quantitatively analyze the mineral abundances by modeling the atmospherically corrected crism ssas using a non negative least squares nnls linear deconvolution algorithm to build the spectral library used for spectral unmixing we use the factor analysis and target transformation fatt technique to recover spectral end members within the crism scenes we investigate several distinct geologic units including an interbedded poly and monohydrated sulfate unit interbedded unit 1 and an interbedded phyllosilicate sulfate unit interbedded unit 2 our spectral unmixing results indicate that polyhydrated sulfates in the interbedded unit 1 have a much lower abundance 10 than that of the surrounding unit 20 and thus may have been partially dehydrated into kieserite to form the interbedded strata supporting a two staged precipitation dehydration formation hypothesis in the interbedded unit 2 phyllosilicates have an abundance of 40 and are interbedded with 20 sulfates the results in combination with thermodynamic calculations performed previously suggest that the interbedded phyllosilicates and sulfates likely formed through coupled basalt weathering and evaporation the methodology developed in this study provides a powerful tool to derive the mineral abundances aiming to better constrain the formation processes of minerals and past aqueous environment on mars

moon near infrared spectral reflectance a first good look a positive identification of the minerals olivine plagioclase and several types of pyroxenes were made at several locations on the lunar surface by using remote measurements for example the crater aristarchus is found to have an average pyroxene composition of augite and plagioclase is obviously present a dark mantle deposit in the crater j herschel is at least partly composed of a mixture of 70o7o olivine and 30o7o pyroxene these determinations were possible because the reflectance spectra for 10 20 km diameter lunar areas have been measured for the first time in the ir spectral region 0 65 2 5 m with sufficient spectral resolution and photometric precision to define mineral electronic absorption bands the reflectance for all lunar regions observed over 100 to present continues to increase toward longer wavelengths to at least 2 5 m and several mineral absorption bands appear the telescopic spectra are of similar quality and contain features similar to laboratory spectra of lunar samples the absorption features in several spectra have been quantitatively analyzed using newly developed computer processing techniques including thermal flux removal and absorption band fitting to produce these mineral identifications detection and quantitative analysis of these absorptions provide a much improved basis for remotely determining and mapping surface mineralogy quantitatively from the ground or using airborne or spacecraft platforms

detection and processing of bistatically reflected gps signals from low earth orbit for the purpose of ocean remote sensing we will show that ocean reflected signals from the global positioning system gps navigation satellite constellation can be detected from a low earth orbiting satellite and that these signals show rough correlation with independent measurements of the sea winds we will present waveforms of ocean reflected gps signals that have been detected using the experiment onboard the united kingdom s disaster monitoring constellation satellite and describe the processing methods used to obtain their delay and doppler power distributions the gps bistatic radar experiment has made several raw data collections and reflected gps signals have been found on all attempts the down linked data from an experiment has undergone extensive processing and ocean scattered signals have been mapped across a wide range of delay and doppler space revealing characteristics which are known to be related to geophysical parameters such as surface roughness and wind speed here we will discuss the effects of integration time reflection incidence angle and examine several delay doppler signal maps the signals detected have been found to be in general agreement with an existing model based on geometric optics and with limited independent measurements of sea winds a brief comparison is presented here these results demonstrate that the concept of using bistatically reflected global navigation satellite systems signals from low earth orbit is a viable means of ocean remote sensing

simulation of l band bistatic returns from the ocean surface a facet approach with application to ocean gnss reflectometry we present the implementation of a facet based simulator to investigate the forward scattering of l band signals from realistic sea surfaces and its application to spaceborne ocean global navigation satellite system gnss reflectometry this approach provides a new flexible tool to assess the influence of the ocean surface roughness on scattered gnss signals the motivation stems from the study by clarizia which revealed significant differences between delay doppler maps ddms obtained from uk dmc satellite data and ddms simulated with the zavorotny voronovich z v model here the scattered power and polarization ratio pr are computed for explicit 3 d ocean wave fields using a novel implementation of the kirchhoff approximation ka which we call the facet approach fa we find that the fa is consistent with the full ka and the geometrical optics go used in the z v model while being less computationally expensive than the ka and able to represent polarization effects not captured by the go instantaneous maps of the bistatic normalized radar cross section computed with the fa show clear patterns associated with the underlying waves the wave field is particularly visible in the pr indicating that the scattering is generally dominated by the hh component particularly from ocean wave troughs polarization effects show for the first time a strong correlation to the explicit sea surface from which the scattering originated ddms of the scattered power computed with the fa reveal patchy patterns and power distributions that differ from those obtained with z v and show closer similarities with observed ddms from uk dmc

a systematic mapping procedure based on the modified gaussian model to characterize magmatic units from olivine pyroxenes mixtures application to the syrtis major volcanic shield on mars clenet et al 2011 have developed an adapted version of the modified gaussian model mgm the improvements allow the characterization of spectra of olivine pyroxene s mixtures addressing both modal composition and individual minerals chemical composition this version of mgm is fully automated and operational with large amounts of hyperspectral imaging data two natural cases are considered the first one is the sumail massif in the oman ophiolite earth based on our approach applied to hymap data two contrasted lithologic units are mapped the mantle which is harzburgite dominated and the crust made of gabbros and clinopyroxene rich cumulates with spectral variations interpreted in terms of pyroxenes chemical compositions once this new mgm mapping approach has been validated on a controlled natural situation we map the distribution of mafic assemblages across the syrtis major volcano on mars using a visible and near infrared vnir short wave infrared swir observatoire pour la mineralogie l eau les glaces et l activite omega mars express mex mosaic our results are in agreement with previous work but olivine appears to be more abundant than previously estimated in the central part of the volcanic edifice especially in ternary mafic assemblages augite olivine enstatite based on these results we propose a possible scenario for the igneous and thus thermal evolution of the syrtis major region surrounding terrains have formed first and local heterogeneity can be observed between northern and southern areas of the noachian crust we also observe variations in the mineral assemblages within syrtis major lavas which can be interpreted in terms of differentiation from a common parent melt and or of a progressive evolution of the mantle source composition and temperature key points mgm systematic mapping on syrtis major to characterize mafic minerals mixtures olivine and pyroxenes mixture is detected in the central lavas of the volcano pyroxenes have chemical compositions spanning the enstatite augite range

spectral reflectance of martian meteorites spectral signatures as a template for locating source region on mars we report the spectral reflectance of martian meteorites from 0 3 2 6 microns for the purpose of cataloguing spectra and the association of their spectral properties with mineralogy and petrology we fit the spectra to a series of overlapping modified gaussian absorptions using least squares fitting the results are validated against established relationships between photon interactions with mineral chemistry and the band parameters these resultant band parameters can be used to constrain interpretations of martian reflectance spectra in the search for the source region of meteorites from mars the limitations of the fitting method are discussed

quantitative compositional analysis of martian mafic regions using the mex omega reflectance data 1 methodology uncertainties and examples of application abstract the mars express observatoire pour la mineralogie l eau les glaces et l activite omega collected an unprecedented visible and near infrared hyperspectral dataset covering the low albedo regions of mars we investigate the ability to infer modal abundance of surfaces of these regions from a radiative transfer model developed by shkuratov et al shkuratov y starukhina l hoffmann h arnold g 1999 icarus 137 235 246 and adapted to basaltic surfaces by poulet and erard poulet f erard s 2004 j geophys res 109 e2 doi 10 1029 2003je002179 from omega measurements of mafic surfaces we develop several sensitivity tests to assess the extent to which the model can be applied to predict pyroxene composition high calcium phase and low calcium phase abundance of almost neutral components plagioclase in the near infrared wavelength as well as grain sizes by using a library of selected end members results of the sensitivity tests indicate that the scattering model can estimate both abundances and grain sizes of major basaltic materials of low albedo regions within uncertainties 5 to 15 vol the model is then applied to data from dissected cratered terrains located in terra meridiani the derived grain size including uncertainties is in the 50 500 m range this is consistent with the thermal inertia and albedo of this region which indicates a fine sand sized surface with little dust the abundances of plagioclase 43 57 and pyroxenes 35 45 10 including 11 5 of low calcium phase are in good agreement with previous basalt like compositions of low albedo regions from thermal infrared spectral measurements the method presented in this paper will provide a valuable tool for evaluating the modal mineralogy of other mafic regions of mars observed in the near infrared wavelength range

color heterogeneity of the surface of phobos relationships to geologic features and comparison to meteorite analogs multispectral observations of phobos by the vsk videospectrometric tv cameras and krfm combined radiometer and photometer for mars uv visible spectrometer on phobos 2 have provided new determinations of the satellite s spectral reflectance properties at greater spatial and spectral resolutions and over a greater geographic range than have previously been available images of the ratio of visible and nir reflectances covering the longitude range 30o 250ow were constructed from 0 40 0 56 pm and 0 781 1 tm vsk images eight channel 0 3 0 6 pm spectra obtained by the krfm instrument package were used to provide greater spectral resolution of parts of these images the data were calibrated using instrumental parameters measured on ground and in flight and the calibrations were refined and tested using previous spectral measurements of phobos and telescopic spectra of mars which is visible in the background in both data sets the average color ratio of phobos was found to be 0 97 0 14 consistent with previously obtained measurements however the surface is heterogeneous with at least four recognizable spectral units whose absolute color ratios were determined to within 10 a red unit with a color ratio of 0 7 0 8 a reddish gray unit with a color ratio of 0 8 1 0 a bluish gray unit with a color ratio of 1 0 1 1 and a blue unit with a color ratio of 1 1 1 4 the red unit occurs in the interiors of several dark floored craters and as adjacent patches the blue unit composes the interior of stickney as well as a lobate deposit superposed on the crater s rim and extending to the southwest the blue lobe is surrounded by a broad bluish gray aureole that breaks up into patchy outliers in its distal portions intervening surfaces are reddish gray the red reddish gray and bluish gray units were sampled by the krfm spectrometer and the bluish gray unit was found to have a distinct 0 3 0 6 grn spectrum the spatial distributions of the color ratio units and their reflectance systematics are inconsistent with mars shine or particle size differences alone being responsible for color variations but lateral optical or compositional heterogeneity is supported by the units different uv visible spectra the redder and bluer color units are interpreted to have been excavated by impacts from an optically and or compositionally heterogeneous interior overlain by a reddish gray surficial layer the location of the blue lobe emanating from stickney correlates with the location of one of the morphologic classes of grooves as predicted by ejecta reimpact models of groove origin the large color ratio of blue material is inconsistent with a carbonaceous chondfite composition but is comparable to that of an assemblage of mafic minerals like that forming black chondrites qualitative and quantitative comparison of the color ratio and uv visible spectral properties of bluish gray material with those of meteorites indicates that black chondfites are this matefial s closest spectral analog the uv visible spectra of reddish gray and red materials most resemble spectra of black chondrites but are also comparable to spectra of some carbonaceous chondrites

a deep crust mantle boundary in the asteroid 4 vesta the asteroid 4 vesta was recently found to have two large impact craters near its south pole exposing subsurface material modelling suggested that surface material in the northern hemisphere of vesta came from a depth of about 20 kilometres whereas the exposed southern material comes from a depth of 60 to 100 kilometres large amounts of olivine from the mantle were not seen suggesting that the outer 100 kilometres or so is mainly igneous crust here we analyse the data on vesta and conclude that the crust mantle boundary or moho is deeper than 80 kilometres

challenges in detecting olivine on the surface of 4 vesta identifying and mapping olivine on asteroid 4 vesta are important components to understanding differentiation on that body which is one of the objectives of the dawn mission harzburgitic diogenites are the main olivine bearing lithology in the howardite eucrite diogenite hed meteorites a group of samples thought to originate from vesta here we examine all the antarctic harzburgites and estimate that on scales resolvable by dawn olivine abundances in putative harzburgite exposures on the surface of vesta are likely at best in the 10 30 range but probably lower due to impact mixing we examine the visible near infrared spectra of two harzburgitic diogenites representative of the 10 30 olivine range and demonstrate that they are spectrally indistinguishable from orthopyroxenitic diogenites the dominant diogenitic lithology in the hed group this suggests that the visible near infrared spectrometer onboard dawn vir will be unable to resolve harzburgites from orthopyroxenites on the surface of vesta which may explain the current lack of identification of harzburgitic diogenite on vesta

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

generalized linear observables for ocean wind retrieval from calibrated gnss r delay doppler maps the cyclone global navigation satellite system cygnss mission will use global navigation satellite system reflectometry to measure ocean surface winds in and near the hurricane inner core including regions beneath the eye wall which could not previously be measured from space due to intense precipitation the cygnss constellation will consist of eight small satellite observatories in 500 km circular orbits at an inclination of 35 cygnss observatories will receive both direct and reflected signals from global positioning system satellites direct signals will be used both for conventional navigation of the observatory positions and for calibration of the incident signal power reflected signals respond to ocean surface roughness from which wind speed is retrieved this is observed as changes in a delay doppler map ddm a generalized observable which is defined as a linear combination of the ddm samples is optimized using three different methods maximum signal to noise ratio minimum variance of the wind speed and principal component analysis pca performance of each of these three approaches is compared with each other and with that of the baseline level 2 retrievals defined for cygnss ddm average leading edge slope and the minimum variance combination of both pca is found to have the best performance

using ddm asymmetry metrics for wind direction retrieval from gps ocean scattered signals in airborne experiments reflectometry of signals of opportunity such as those emitted by a global navigation satellite system known as gnss r has been developed over the past years as a technique with great potential for ocean scatterometry among other applications different approaches have been proposed to use gnss r for remote sensing of ocean surface roughness one of them is based on deriving some descriptor metric from the measured delay doppler map ddm and directly relating it to a geophysical property of the scattering surface for instance different descriptors have been proposed in the literature to measure the ddm spreading caused by the increase in ocean surface mean square slopes due to surface winds in this paper a new descriptor based on the ddm is proposed for wind direction retrieval this descriptor designated as the skewness angle 1 skew measures the asymmetry in the ddm power distribution along the doppler frequency axis and it was modeled as a function of wind direction by means of a simulation study then that model was validated using real gnss r data from an airborne experiment after validation the ddm skewness model was successfully used for wind direction retrieval with a resulting rms error on the order of 20

near infrared spectral reflectance of mineral mixtures systematic combinations of pyroxenes olivine and iron oxides near infrared spectral reflectance data are presented for systematic variations in weight percent of two component mixtures of ferromagnesian and iron oxide minerals mixtures were chosen for application to the study of the dark materials on mars but the results are equally applicable to mafic and ultramafic assemblages elsewhere in the solar system olivine spectral features are greatly reduced in contrast by admixture of other phases but remain distinctive even for low olivine contents clinopyroxene and orthopyroxene mixtures show resolved pyroxene absorptions near 2 m the addition of limonite greatly modifies pyroxene and olivine reflectance but does not fully eliminate distinctive spectral characteristics using only spectral data in the 1 m region it is difficult to differentiate orthopyroxene and limonite goethite in a mixture additional spectral coverage or other evidence may be required for a unique interpretation all composite mineral absorptions observed in this study are either weaker than or intermediate in strength to the end member absorptions and have bandwidths greater than or equal to those for the end members in general spectral properties in an intimate mixture combine in a complex nonadditive manner with features demonstrating a regular but usually nonlinear variation as a function of end member phase proportions

5 cm precision aircraft ocean altimetry using gps reflections 1 we present the first two aircraft global positioning system gps reflection altimetry measurements the most precise gps ocean altimetry measurement and demonstrate the altimetric precision and spatial resolution necessary to map mesoscale eddies our first experiment demonstrated a 14 cm precision single satellite ocean altimetry measurement while our more recent experiment demonstrates 5 cm altimetric precision with 5 km spatial resolution the new results show significant improvement over our previous effort due to improved modeling greater aircraft altitudes and velocities improved receiver positioning and better experimental control plans to further reduce speckle and refine models to obtain 5 cm altimetric accuracy are presented

scattering of gps signals from the ocean with wind remote sensing application a theoretical model that describes the power of a scattered global positioning system gps signal as a function of geometrical and environmental parameters has been developed this model is based on a bistatic radar equation derived using the geometric optics limit of the kirchhoff approximation the waveform i e the time delayed power obtained in the delay mapping technique depends on a wave slope probability density function which in turn depends on wind waveforms obtained for aircraft altitudes and velocities indicate that altitudes within the interval 5 15 km are the best for inferring wind speed in some regimes an analytical solution for the bistatic radar equation is possible this solution allows converting trailing edges of waveforms into a set of straight lines which could be convenient for wind retrieval a transition to satellite altitudes together with satellite velocities makes the peak power reduction and the doppler spreading effect a significant problem for wind retrieval based on the delay mapping technique at the same time different time delays and different doppler shifts of the scattered gps signal could form relatively small spatial cells on sea surface suggesting mapping of the wave slope probability distribution in a synthetic aperture radar sar fashion this may allow more accurate measurements of wind velocity and wind direction

2 cm gps altimetry over crater lake dierences in electromagnetic path delay be tween direct global positioning system gps signals and those reflected from the surface of crater lake have led to lake surface height estimates with 2 cm precision in 1 sec ond this is the rst high precision altimetric demonstra tion with gps from sucient altitude 480 m to probe fundamental experimental errors which bear on future air and spaceborne passive gps altimetry it also serves as the rst demonstration of a new approach to altimetric remote sensing in the coastal region an area that is poorly mea sured by conventional radar altimetry time series analy sessuggest thattroposphericandthermalnoisefluctuations dominate the altimetric error in this experiment estimat ing the dierential delay from several simultaneously visi ble satellites may enable tropospheric error estimation and correction thermal noise on the reflected signal will be reduced with fully polarimetric observations and larger an tenna apertures

olivine bearing lithologies on the moon constraints on origins and transport mechanisms from m 3 spectroscopy radiative transfer modeling and grail crustal thickness abstract high resolution hyperspectral data from chandrayaan 1 s moon mineralogy mapper m 3 allow detection of olivine on the lunar surface olivine exposed at the surface may originate as mantle material or igneous products intrusive or extrusive potential transport mechanisms include excavation of the mantle or lower crustal material by impacts that form basins and complex craters differentiation of impact melt sheets or magmatic emplacement of lavas cumulates or xenoliths a sample of the lunar mantle which has not been conclusively identified in the lunar sample collection would yield fundamental new insights into the composition structure and evolution of the lunar interior olivine identified in remote spectral data is generally accepted to originate from the primary mantle because abundant olivine is expected to exist in the mantle and lower crust yet have sparse occurrences in the upper crust in this study we identified 111 m 3 single pixel spectra with characteristic absorption features consistent with olivine at crisium nectaris and humorum basins and near the craters roche and tsiolkovsky in an effort to determine the origins and transport mechanisms that led to these individual exposures we estimated mineral abundances using radiative transfer modeling and examined crustal thickness estimates topography and slope maps and images from the lunar reconnaissance orbiter camera lroc at crisium basin where crustal thickness is near 0 km wieczorek et al 2013 mantle olivine may have been exposed by basin forming impact and deposited on the rim picard crater which is superposed on the floor of crisium also exhibits potential mantle olivine in its ejecta within nectaris basin olivine exposures are confined to the rims of small craters on the mare which are inferred to excavate a layer of olivine rich mare basalt olivine occurrences on the rim of humorum basin including those located on a graben are likely to be cumulates of shallow intrusions that were transported magmatically to the surface near roche crater olivine may have originated in shallow dikes that reached the subsurface and were exposed by impacts in addition to verifying both known and previously unidentified olivine exposures our combined geophysical spectral and radiative transfer modeling investigation has allowed identification of both igneous and mantle derived olivine

complexities in pyroxene compositions derived from absorption band centers examples from apollo samples hed meteorites synthetic pure pyroxenes and remote sensing data we reexamine the relationship between pyroxene composition and near infrared absorption bands integrating measurements of diverse natural and synthetic samples we test an algorithm plc involving a two part linear continuum removal and parabolic fits to the 1 and 2 m bands a computationally simple approach which can easily be automated and applied to remote sensing data employing a suite of synthetic pure pyroxenes the plc technique is shown to derive similar band centers to the modified gaussian model plc analyses are extended to natural pyroxene bearing materials including 1 bulk lunar basalts and pyroxene separates 2 diverse lunar soils and 3 hed meteorites for natural pyroxenes the relationship between composition and absorption band center differs from that of synthetic pyroxenes these differences arise from complexities inherent in natural materials such as exsolution zoning mixing and space weathering for these reasons band center measurements of natural pyroxene bearing materials are compositionally nonunique and could represent three distinct scenarios 1 pyroxene with a narrow compositional range 2 complexly zoned pyroxene grains or 3 a mixture of multiple pyroxene or nonpyroxene components therefore a universal quantitative relationship between band centers and pyroxene composition cannot be uniquely derived for natural pyroxene bearing materials without additional geologic context nevertheless useful relative relationships between composition and band center persist in most cases these relationships are used to interpret m3 data from the humboldtianum basin four distinct compositional units are identified 1 mare humboldtianum basalts 2 distinct outer basalts 3 low ca pyroxene bearing materials and 4 feldspathic materials

visible and near infrared spectra of carbonate rocks reflectance variations related to petrographic texture and impurities grain size statistics derived from thin section point measurements were used to classify carbonate rock textures and to identify related spectral characteristics in the visible and near infrared 0 4 2 5 m wavelength range although the statistics did not permit all the carbonate textural varieties generally recognized by petrologists to be distinguished three broad textural classes of pure carbonate material were found that produced distinctive spectra further refinement of the statistical technique may permit other textural classes to be identified however internal scattering in carbonate rocks is a complex phenomenon involving the grain size distribution as well as the nature and abundance of inclusions and internal grain defects to yield an optimum textural classification for spectroscopic studies all such scattering contributors would have to be quantified the spectral effects of iron oxide clay silica and organic matter impurities were examined by comparing texturally similar pure and impure carbonate rock samples of these impurities organic matter had the greatest spectral influence and amounts as low as 0 01 wt commonly caused marked reductions in sample brightness and absorption band intensity in contrast the spectral effects of rock texture were subtle and could only be identified in samples that were nearly free of organic matter impurities the pronounced organic matter spectral effects imply that the organic matter in most carbonates is very finely disseminated samples collected from different regions usually showed different degrees of organic spectral quenching however no correlations were evident between sample reflectance and contained kerogen h c ratios or kerogen amounts additional analytical work is needed to examine organic matter compositional variation and associated spectral quenching effects in detail from the present study it appears likely that contained organic matter will be a dominant factor in the visible and near infrared spectral expression for most carbonate rocks and perhaps for other sedimentary lithologies spectral quenching by organic matter will likely complicate remote sensing and laboratory spectral determinations of carbonate composition on the other hand variations in quenching may prove to be useful for distinguishing rocks that have experienced unusual diagenetic thermal or other conditions affecting the organic matter contents

iron mineralogy of the surface of mars from the 1 μm band spectral properties 1 we study the 1 m absorption from omega mex spectra to map martian iron mineralogy at a global scale this band is covered on the left by the vnir visible and near infrared omega channel and on the right by the swir short wavelengths infrared one we first perform a systematic spatial coregistration of the two channels after an improvement of the vnir radiometric calibration the update of the vnir instrumental transfer function itf and the internal stray light estimation is based on the spectra of the phobos red units and of the water ice north polar cap of mars which have been fitted according to an iterative process the level of the signal in the blue wavelength range previously systematically overestimated due to a stray light residual and the general shape of the spectrum for 0 7 m are improved global maps of the 1 m signature have been derived from 9 new spectral indices the largest values of the 1 m band integral are found in noachian terrains and in the dunes around the north polar cap in the south polar region an area centered at 155 w and 83 s is mapped as a distinctive spectral unit dominated by pyroxene the northern lowlands of mars together with other dark terrains located in the northern hemisphere show very low values of some spectral indices due to the negative spectral slope in the nir this behavior is consistent with the presence of weathered basalts with a possible glassy or amorphous component among the hydrated terrains the only ones that can be isolated by studying the 1 m band are those located in terra meridiani aram chaos and capri chasma enriched in sulfate and hematite on the other hand the sulfates of the dark dunes surrounding the northern polar cap and the phyllosilicates of the bright hydrated deposits of mawrth vallis cannot be isolated combining the parameters used in this study this suggests that their distinctive mineralogy does not affect the 1 m band remaining similar to the global martian average shape

influences of intraseasonal disturbances on the oceanic mixed layer in the western north pacific itcz region 1 using the argo float data changes in the temperature and salinity in the oceanic mixed layer corresponding to the passage of intraseasonal scale disturbances were examined over the western north pacific wnp intertropical convergence zone itcz region events where the near surface temperature decreased by more than 1 c within a 10 day period were identified corresponding to the intraseasonal variability isv of the atmosphere analyzing the vertical profiles and the t s relationships of the mixed layer revealed that the water was cooled mainly by mechanical mixing and ekman upwelling related to the strong sea surface wind thermal cooling at the sea surface does not appear to be a predominant process in the abrupt cooling such cooling events were observed only when the mixed layer was shallow

meteorite and asteroid reflectance spectroscopy clues to early solar system processes although earth has a magnetic shield that protects it from energetic ions and a cushioning atmosphere that catches the tons of small particles i mm that bombard it daily solid material from extraterrestrial sources nevertheless reaches the surface of earth many times a year dodd 1 98 1 when the largest of these bodies impact the surface with great velocity they release immense energy usually form a crater and often disrupt the terrestrial biosphere fortunately such events occur relatively infrequently although individual impacts are currently unpredictable beyond a statistical accounting shoemaker et al 1979 grieve 1 982 cosmic material between the size of small dust particles and the larger crater forming bodies is slowed by the terrestrial atmosphere upon entry the outermost portion of these objects is melted and ablated during passage forming a fusion crust which protects the interior and they land

rapid discrimination of granitic rock compositions by low resolution near infrared reflectance the slopes of near infrared spectra between approximately 1 and 2 microns from quartz bearing plutonic rocks are strongly correlated with rock chemistry determined by x ray spectrometry the empirically derived predictive equations provide compositional data of adequate precision and resolution to discern patterns of regional geochemical variation in granitic batholithic rocks of southern california as an analytical method infrared spectrometry is rapid and inexpensive and the method has potential in applications to direct field measurements and to data from aircraft and spacecraft scanner systems of relatively low spectral and spatial resolution provided vegetative cover and surface alteration are not prohibitively masking

near infrared spectroscopy of probable impact melt from three large lunar highland craters abstract the composition of small areas within three large lunar highland craters are compared using near infrared earth based telescopic data spectra from many areas in the walls and central peaks of the craters indicate the presence of crystalline components which include olivine two types of pyroxene and sometimes fe bearing feldspar spectra from other regions suspected of being impact melt deposits located on the floors and walls of the three craters have remarkably similar yet anomalous features these features are interpreted to indicate the presence of pyroxene fe bearing glass and fe bearing feldspar pyroxene and feldspar are believed to occur primarily in the form of lithic clasts and rapidly recrystallized impact melt the fe bearing glass is interpreted as impact melt glass

possible temperature variation effects on the interpretation of spatially resolved reflectance observations of asteroid surfaces abstract the visible and near ir spectral reflectance of some minerals is a function of temperature hence surface temperature variation must be considered for mineralogical interpretation of spectral reflectance data obtained from a spatially resolved surface which has a temperature distribution an example is presented to illustrate the errors which can be encountered when interpreting the spectral reflectance of a silicate mineral assemblage measured at various temperatures that might be expected across an asteroid surface independent knowledge of the surface temperature distribution would allow the optimal extraction of mineralogical information in such cases

an in depth look at the lunar crater copernicus exposed mineralogy by high resolution near infrared spectroscopy abstract newly acquired sequentially spaced high resolution near infrared spectra across the central section of crater copernicus interior have been analyzed using a range of complementary techniques and indexes we have developed a new interpretative method based on a multiple stage normalization process that appears to both confirm and expand on previous mineralogical estimations and mapping in broad terms the interpreted distribution of the principle mafic species suggests an overall composition of surface materials dominated by calcium poor pyroxenes and minor olivine but with notable exceptions the southern rim displays strong ca rich pyroxene absorption features and five other locations the uppermost northern crater wall opposite rim sections facing the crater floor and the central peak pk1 and at the foot of pk3 show instead strong olivine signatures we also propose impact glass an alternative interpretation to the source of the weak but widespread olivine like spectral signature found in low reflectance samples since it probably represents a major regolith constituent and component in large craters such as copernicus the high quality and performance of the sir 2 data allows for the detection of diagnostic key mineral species even when investigating spectral samples with very subdued absorption features confirming the intrinsic high quality value of the returned data

volcanic glass signatures in spectroscopic survey of newly proposed lunar pyroclastic deposits moon mineralogy mapper spectroscopic observations are used to assess the mineralogy of five sites that have recently been proposed to include lunar dark mantle deposits dmds volcanic glasses have for the first time clearly been identified at the location of three of the proposed pyroclastic deposits this is the first time that volcanic glasses have been identified at such a small scale on the lunar surface from remote sensing observations deposits at birt e schluter and walther a appear to be glassy dmds deposits at birt e and schluter show 1 morphological evidence suggesting a likely vent and 2 mineralogical evidence indicative of the presence of volcanic glasses the walther a deposits although they show no morphological evidence of vents have the spectroscopic characteristics diagnostic of volcanic glasses the deposits of the freundlich sharonov basin are separated in two areas 1 the buys ballot deposits lack mineralogical and morphological evidence and thus are found to be associated with mare volcanism not with dmds and 2 the anderson crater deposits which do not exhibit glassy dmd signatures but they appear to be associated with possible vent structures and so may be classifiable as dmds finally dark deposits near the crater kopff are found to be associated with likely mare volcanism and not associated with dmds the spectral identification of volcanic glass seen in many of the potential dmds is a strong indicator of their pyroclastic origin

mineralogical variation of the late stage mare basalts the last major phases of lunar volcanism occurred mainly in oceanus procellarum and mare imbrium and produced spectrally unique medium and high titanium basalts the composition and distribution of these basalts provide a record of the late stage thermal evolution of the moon to study the spectral and mineralogical variations of the late stage mare basalts 31 distinct units were mapped employing a range of remote sensing data their inferred mineralogical characteristics were studied by analyzing the spectral features of small fresh craters derived from the moon mineralogy mapper m3 data the strongest olivine spectral signatures were found around lichtenberg crater while the units with the lowest olivine pyroxene ratio occurred mainly in the southern kepler crater and some local areas in oceanus procellarum the olivine pyroxene ratio decreases progressively from the lichtenberg crater to the southern units the northern and southern units within mare imbrium have higher olivine pyroxene ratios than the central ones the inferred abundance of olivine appears to vary stratigraphically with the younger flows being more olivine rich however the stratigraphically younger units around euler crater in mare imbrium which present as dark red hues in the integrated band depth image of m3 were found to have lower olivine pyroxene ratios than the units around lichtenberg crater shown as light red hues in oceanus procellarum it could be interpreted that the late stage mare basalts around lichtenberg crater originated from a more olivine rich source than those around euler crater

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

remote sensing of lunar pyroclastic mantling deposits abstract mantling deposits on the moon are considered to be pyroclastic units emplaced on the lunar surface as a result of explosive fire fountaining these pyroclastic units are characterized as having low albedos having smooth fine textured surfaces and consisting in part of homogeneous febearing volcanic glass and partially crystallized spheres mantling units exhibit low returns on depolarized 3 8 cm radar maps indicating an absence of surface scatterers in the 1 to 50 cm size range a number of reflectance spectra from several regional pyroclastic deposits are presented for the first time these data support a previous interpretation that mantling units have a unique spectral signature which is indicative of the presence of a significant fe bearing volcanic glass component the rima bode region is discussed as an example of an area in which several types of remote sensing data including 3 8 cm radar spectral reflectance and multispectral vidicon data were used to reconstruct the geologic events surrounding the emplacement of a regional pyroclastic mantling deposit the recognition of numerous varieties of volcanic glass samples especially relatively high albedo e g green yellow glasses suggests the existence of additional unrecognized mantling deposits with albedos higher than those studied to date on the basis of the remote sensing data summarized and presented five new areas have been identified which may represent higher albedo regional pyroclastic deposits

land geophysical parameters retrieval using the interference pattern gnss r technique in the past years the scientific community has placed a special interest in remotely sensing soil moisture and vegetation parameters radiometry and radar techniques have been widely used for years global navigation satellite systems opportunity signals reflected gnss r over the earth s surface are younger but they have already shown their potential to perform these observations this paper presents a gnss r technique based on global positioning system gps measurements that allows the retrieval of several geophysical parameters from land surfaces this technique measures the power of the interference signal between the direct gps signal and the reflected one after scattering over the land so it is called interference pattern technique ipt this paper presents the results obtained after applying the ipt for topography soil moisture and vegetation height retrievals over vegetation covered soils

reflectance spectra of featureless materials and the surface mineralogies of m and e class asteroids this study was supported by grants in aid of research from the central research fund of the university of alberta to d g w s from sigma xi the scientific research society and the geological society of america 3741 87 to e a c and nasa planetary geology and geophysics grant nagw 642 to m j g

mediterranean balloon experiment ocean wind speed sensing from the stratosphere using gps reflections abstract the mediterranean balloon experiment mebex conducted in august 99 from the middle up stratosphere was designed to assess the wind retrieval sensitivity of global navigation satellite systems reflections gnssr technology from high altitudes global positioning system reflected signals gpsr collected at altitudes around 37 km with a dedicated receiver have been inverted to mean square slopes mss of the sea surface and wind speeds the theoretical tool to interpret the geophysical parameters was a bistatic model which also depends on geometrical parameters the results have been analyzed in terms of internal consistency repeatability and geometry dependent performance in addition wind velocities have been compared to independent measurements by quikscat topex ers ra and a radio sonde with an agreement better than 2 m s a numerical weather prediction model nwpm the mm5 mesoscale forecast model has also been used for comparison with varying results during the experiment the conclusion of this study confirms the capability of high altitude gpsr delay map receivers with low gain antennas to infer surface winds

synergistic ground and orbital observations of iron oxides on mt sharp and vera rubin ridge visible short wave infrared spectral data from the compact reconnaissance imaging spectrometer for mars crism show absorptions attributed to hematite at vera rubin ridge vrr a topographic feature on northwest mt sharp the goals of this study are to determine why absorptions caused by ferric iron are strongly visible from orbit at vrr and to improve interpretation of crism data throughout lower mt sharp these goals are achieved by analyzing coordinated crism and in situ spectral data along the curiosity mars rover s traverse vrr bedrock within areas that have the deepest ferric absorptions in crism data also have the deepest ferric absorptions measured in situ this suggests strong ferric absorptions are visible from orbit at vrr because of the unique spectral properties of vrr bedrock dust and mixing with basaltic sand additionally inhibit the ability to measure ferric absorptions in bedrock stratigraphically below vrr from orbit there are two implications of these findings 1 ferric absorptions in crism data initially dismissed as noise could be real and ferric phases are more widespread in lower mt sharp than previously reported 2 patches with the deepest ferric absorptions in crism data are like vrr reflective of deeper absorptions in the bedrock one model to explain this spectral variability is late stage diagenetic fluids that changed the grain size of ferric phases deepening absorptions curiosity s experience highlights the strengths of using crism data for spectral absorptions and associated mineral detections and the caveats in using these data for geologic interpretations and strategic path planning tools

sea surface state measured using gps reflected signals we discuss an airborne experiment aimed to establish the potential of the paris concept passive reflectometry and interferometry system to retrieve small features in the sea surface topography the date and location were chosen to coincide with a topex poseidon t p overflight the signals of the global positioning system gps reflected off the sea surface are tracked and compared to the directly received ones to compute the relative delays the features detected in the peak tracking are likely caused by topographic and sea roughness variations while very promising these results open the challenge to use additional information to appropriately separate both contributions

the mineralogy of late stage lunar volcanism as observed by the moon mineralogy mapper on chandrayaan 1 1 the last major phases of lunar volcanism produced spectrally unique high titanium basalts on the western nearside of the moon the moon mineralogy mapper m3 on chandrayaan 1 has provided detailed measurements of these basalts at spatial and spectral resolutions necessary for mineralogical interpretation and mapping of distinct compositional units the m3 imaging spectrometer acquired data in 85 spectral bands from 430 to 3000 nm at 140 to 280 m pixel in its global mapping mode during the first half of 2009 reflectance data of several key sites in the western maria were also acquired at higher spatial and spectral resolutions using m3 s target mode prior to the end of the chandrayaan 1 mission these new observations confirm that both fresh craters and mare soils within the western high ti basalts display strong 1 m and weak 2 m absorptions consistent with olivine rich basaltic compositions the inferred abundance of olivine is observed to correlate with stratigraphic sequence across different mare regions and absolute ages the apparent stratigraphic evolution and fe rich compositions of these basalts as a whole suggest an origin from evolved residual melts rather than through the assimilation of more primitive olivine rich sources mare deposits with spectral properties similar to these late stage high ti basalts appear to be very limited outside the procellarum imbrium region of the moon and where present appear to occur as small areas of late stage regional volcanism detailed analyses of these new data and supporting measurements are in progress to provide further constraints on the mineralogy olivine abundance and compositions of these final products of lunar volcanism and the nature and evolution of their source regions

influence of mechanical mixing on a low summertime sst in the western north pacific itcz region 1 a region with a low sea surface temperature sst was identified in the western north pacific wnp intertropical convergence zone itcz or warm water pool region in boreal summer the sst decreases by up to 0 5 c from may to the june july august jja season just east of mindanao island analyses of the observed data indicated that a northeastward surface current constantly exists throughout the year supplying cold subsurface water through the molucca strait as a result the subsurface water is colder by several degrees compared with that in the surrounding regions the sea surface wind is strong over this region in the jja season examination of argo float data demonstrated that the mixed layer becomes deeper from may to the jja season it is suggested that the strong wind causes vertical mixing between the surface and subsurface layers resulting in the low summertime sst