fast and accurate estimation of solar irradiance on martian slopes 1 a general parameterization is proposed in this study to calculate in a mars like dusty atmosphere the solar irradiance reaching an inclined surface assuming the value in the horizontal case is known complete monte carlo radiative transfer calculations using the ockert bell et al 1997 dust optical properties enable the validation of the method for mars the total shortwave flux reaching the surface is composed of three contributions direct incoming flux reflected flux by surrounding terrains and scattered flux by the atmospheric dust the main difficulty is the parameterization of the latter component we show that the scattered flux reaching the slope can be expressed by a physically based simple formula involving one empirical coupling matrix and two vectors accounting for the scattering properties and the geometrical settings the final result is a computationally efficient parameterization with an accuracy in most cases better than 5 w m 2 such a fast and accurate method to calculate solar irradiance on martian slopes should they be topographical surfaces or solar panels is of particular interest in a wide range of applications such as remote sensing measurements geological and meteorological models and mars exploration missions design

mars express high resolution stereo camera spectrophotometric data characteristics and science analysis 1 the high resolution stereo camera hrsc on the mars express mex spacecraft in orbit about mars is delivering images of the mars surface and atmosphere from its high inclination elliptical orbit that are intended to cover most of the mars surface by the end of the mission these are acquired in four specific spectral passbands that sample the scene at different parts of the extended visual spectrum from near 0 4 m to about 1 m and in five additional channels four used for stereo and one nadir that use the same fifth spectral passband these channels view from different angles and can be used for photometric and spectral analysis the data allow a variety of studies of the surface and atmosphere of mars but these require detailed understanding of the data characteristics as there are several effects including of the observation geometry and the atmosphere that need to be treated this article is a report to the science community on the current understanding of the hrsc color data after an initial analysis and also a demonstration of their capabilities for study of mars which from this study appear to be considerable we first discuss the characteristics and calibration of the hrsc spectral data the atmospheric influence on the photometric appearance of the surface materials is explored and methods of compensating are considered reflectances are calculated for surface units by assuming the dark material is basalt and scaling the entire hrsc scene using a laboratory basalt spectrum for the selected dark material area the results and the correction factors for different orbits are compared we present several examples of what could become a large volume of future science results utilizing the hrsc spectrophotometric data in conjunction with photo interpretation for example we find relatively few but very important distinct spectral components at the hrsc resolution including what we interpret as iron oxide rich material unoxidized basalt and polar ice consistent with past works the major spectral components are distributed in ways that suggest compositional mixing and the need to revise the current geologic understanding of major regions

hydration state of calcium sulfates in gale crater mars identification of bassanite veins abstract in situ analyses reveal the presence of hydrogen within calcium sulfate veins crosscutting the sediments found in gale crater laboratory experiments were performed to calibrate the hydrogen signal measured by laser induced breakdown spectroscopy libs in a range applicable to martian data the analyses indicate that all veins targeted so far at gale consist predominantly of bassanite which most likely formed by dehydration of gypsum this scenario suggests that the percolating water produced gypsum possibly by hydration of anhydrite in aqueous solution and remained at temperatures below 60 c at that time desiccating conditions followed consistent with a hyperarid climate and favored by burial or impacts additionally anhydrite with lesser bassanite has been found by xrd in samples of sediments hosting the veins our result suggests bassanite is likely found in the veins and anhydrite may be more common as a fine grained component within the sediments

martian high latitude permafrost depth and surface cover thermal inertia distributions 1 martian high latitudes have thermal properties consistent with an extensive high thermal inertia permafrost layer near the surface surface cover thermal inertias and permafrost depths at martian high latitudes 50 80 n s are derived from thermal emission spectrometer tes data and compared with previously published water ice depths determined from the mars odyssey neutron spectrometer mons the depth to the permafrost layer is correlated with surface cover thermal inertia albedo and latitude in general agreement with predicted trends of water ice stability comparison of permafrost depths with water ice rich layer depths derived from mons data displays good qualitative agreement although a divergence is present at greater burial depths this disparity may be due to the presence of hydrated minerals at shallow depths or a lower than expected permafrost thermal inertia corresponding with low water ice concentrations at greater depths surface cover thermal inertias are greater in the northern high latitudes than in the south and differences between these and previous results will have significant effects on the predicted depth of martian water ice stability several regions in the northern hemisphere display high surface cover thermal inertia associated with possible receding water ice deposits that are shallow enough to influence diurnal surface temperatures significant lateral and vertical heterogeneity in water ice distributions are present and the martian regolith is likely more complicated than can be described by simple two layered models and a single mode of water ice emplacement

lunar surface roughness derived from lro diviner radiometer observations abstract sunlit and shaded slopes have a variety of temperatures based on their orientation with respect to the sun generally greater slope angles lead to higher anisothermality within the field of view this anisothermality is detected by measuring changing emitted radiance as a function of viewing angle or by measuring the difference in brightness temperatures with respect to observation wavelength thermal infrared measurements from the lunar reconnaissance orbiter diviner radiometer were used to derive lunar surface roughness via two observation types 1 nadir multispectral observations with full diurnal coverage and 2 multiple emission angle targeted observations measurements were compared to simulated radiance from a radiative equilibrium thermal model and gaussian slope distribution model nadir observations most closely match a 20 rms slope distribution and multiple emission angle observations can be modeled using 20 35 rms slope distributions limited sampling of the lunar surface did not show any clear variation in roughness among surface units two dimensional modeling shows that surfaces separated by distances greater than 0 5 5 mm can remain thermally isolated in the lunar environment indicating the length scale of the roughness features non equilibrium conditions are prevalent at night and near sunrise and sunset preventing the use of the equilibrium thermal model for roughness derivations using data acquired at these local times multiple emission angle observations also show a significant decrease in radiance at high emission angles in both daytime and nighttime observations and hemispherical emissivity is lower than is apparent from nadir observations these observations and models serve as a basis for comparison with similar measurements of other airless bodies and as an initial template for the interpretation of tir measurements acquired under a variety of geometric conditions

observations of the south seasonal cap of mars during recession in 2004 2006 by the omega visible near infrared imaging spectrometer on board mars express 1 the omega visible near infrared imaging spectrometer on board mars express has observed the southern seasonal cap in late 2004 and 2005 and then in the summer of 2006 these observations extended from the period of maximum extension close to the southern winter solstice to the end of the recession at ls 325 the spectral range and spectral resolution of omega make it possible to monitor the extent and effective grain size of co2 ice and h2o ice on the ground the level of contamination of co2 ice and h2o ice by dust and the column density of m sized ice grains in the atmosphere the co2 seasonal cap is very clean and clear in early southern winter contamination by h2o ice spreads eastward from the hellas basin until the southern spring equinox during southern spring and summer there is a very complex evolution in terms of effective grain size of co2 ice and contamination by dust or h2o ice h2o ice does not play a significant role close to the southern summer solstice contamination of co2 ice by h2o ice is only observed close to the end of the recession as well as the few h2o ice patches already reported by bibring et al 2004a these observations have been compared to the results of a general circulation model with good qualitative agreement on the distribution of h2o ice on the surface and in the atmosphere resolving the remaining discrepancies will improve our understanding of the water cycle on mars

thermal properties of sand from thermal emission spectrometer tes and thermal emission imaging system themis spatial variations within the proctor crater dune field on mars 1 thermal inertia a parameter calculated from surface temperatures obtained from spacecraft has long been used to quantify the amount of loose fine grained material on the martian surface with little ground truth available studies often refer to martian dune fields to calibrate thermal inertias the well understood physical properties of dune sand make it an ideal basis for comparison to more complex surfaces however higher resolution data sets available from the tes thermal emission spectrometer onboard mars global surveyor and themis thermal emission imaging system onboard mars odyssey show spatial variations in the thermal properties within dune fields calling into question their effectiveness as controls for thermal inertia studies in order to explain these variations we apply a thermal model developed for tes data to a commonly investigated dune field in noachis terra that on the floor of proctor crater we show that in this dune field the thermal variations on the scale of 30 j m 2 s 0 5 k 1 are present and correlate spatially with aeolian features in the dune field these variations correspond to three types of surfaces observed in the mars orbital camera narrow angle moc na images 1 dune sand 2 interdunes exposing the surface underlying the dune field and 3 sand covered interdunes or dune troughs both the interdunes and the dune troughs have cooler nighttime temperatures than the dune sand corresponding to lower thermal inertia values the dune troughs may be sand covered areas with either minor amounts of dust accumulation or a mean sand grain size lower than that of dune sand because fine sand grains tend to preferentially accumulate on dune crests rather than in dune troughs the second hypothesis is considered less likely than the first this has implications for the recent sedimentary history of the dune field dust accumulation in dune troughs may imply that sand saltation is not prevalent enough to scour away all of the dust settling out from suspension in the atmosphere however it is prevalent enough to keep the dunes crests themselves clear of dust

high resolution thermal inertia derived from the thermal emission imaging system themis thermal model and applications 1 thermal inertia values at 100 m per pixel are determined using nighttime temperature data from the thermal emission imaging system themis on the mars odyssey spacecraft producing the highest resolution thermal inertia data set to date themis thermal inertia values have an overall accuracy of 20 a precision of 10 15 and are consistent with both thermal emission spectrometer orbital and miniature thermal emission spectrometer surface thermal inertia values this data set enables the improved quantification of fine scale surface details observed in high resolution visible images in the tharsis region surface textures and crater rims observed in visible images have no corresponding variation in the themis thermal inertia images indicating that the dust mantle is pervasive at themis scales and is a minimum of a few centimeters and up to 1 2 m thick the thermal inertia of bed form material indicates particle diameters expected for aeolian sediments and these materials are likely currently saltating variations in the thermal inertia within interior layered deposits in hebes chasma can be distinguished and the thermal inertia is too low to be consistent with bedrock or a lava flow thus a secondary emplacement of volcanic material or a volcanic ash deposit is a more likely method of formation higher resolution themis thermal inertia enables the identification of exposed bedrock on the martian surface in nili patera and ares vallis bedrock material corresponds to distinct compositional and morphologic surfaces indicating that a specific unit is exposed and is likely currently being kept free of unconsolidated material by aeolian processes

spirit mars rover mission overview and selected results from the northern home plate winter haven to the side of scamander crater spirit mars rover mission overview and selected results from the northern home plate winter haven to the side of scamander crater

rock abundance on mars from the thermal emission spectrometer 1 nighttime infrared spectral observations returned from the mars global surveyor thermal emission spectrometer tes are well suited for determining the subpixel abundance of rocks on the surface of mars the algorithm used here determines both the areal fraction of rocky material and the thermal inertia of the fine grained nonrock component present on the surface rock is defined as any surface material that has a thermal inertia 1250 j m 2 k 1 s 1 2 this can be bedrock boulders indurated sediments or a combination of these on a surface mixed with finer grained materials over 4 9 million observations were compiled to produce the 8 pixels per degree global rock abundance and fine component inertia maps total coverage is 45 of the planet between latitudes 60 and 60 less than 1 of the planet has rock abundances greater than 50 and 7 of the mapped surface has greater than 30 rocks rocky regions on mars correspond primarily to the high inertia surfaces observed in thermal inertia data sets the fine component inertia data set is used to identify high inertia exposures that contain few rocks and more homogeneous materials

distribution recruitment and geomorphic significance of large woody debris in an alluvial forest stream tonghi creek southeastern australia the complex yet poorly understood interactions between riparian vegetation large woody debris and fluvial geomorphology in an anthropogenically undisturbed reach of an alluvial sand bed forest stream in se australia have been determined riparian vegetation exhibits lateral and vertical zonation of understorey and overstorey species the dominant riparian tree species tristaniopsis laurina water gum grows within the channel and on the floodplain within one channel width of the stream larger eucalyptus species only grow on the highest parts of the floodplain and on a low pleistocene river terrace a complete large woody debris lwd census conducted in the 715 m long study reach revealed that water gum comprises 17 6 of the total lwd loading which at 576 m 3 ha 1 is high for a stream with a catchment area of 187 km 2 although most lwd has a small diameter 0 1 0 3 m the greatest contribution to the total volume of lwd is by pieces with a diameter between 0 3 and 0 7 m a high proportion of lwd 10 4 has a blockage ratio greater than 10 the spatial distribution of lwd is random both longitudinally and within individual meander bends dominant recruitment processes of lwd vary by species t laurina trees are recruited to the channel by minor bank erosion and senescence while the eucalyptus species are predominantly recruited from the highest parts of the floodplain low river terrace by episodic windthrow during large storms multiple radiocarbon dates of outer wood of immobile lwd indicate a maximum residence time of 240f40 years bp for t laurina timber the high loading of lwd combined with the extensive root systems of riparian vegetation stabilize tonghi creek log steps form natural wooden drop structures with a mean height of 29 mm that were responsible for 20 5 of the total head loss under base flow conditions q 0 08 m 3 s 1 large woody debris is buried in the bed at depths of up to 2 3 m and is responsible for an estimated 49 of the 11 600 m 3 of sand stored in the study reach pools are spaced at 0 8 channel widths and 82 of pools are formed by scour over under around or beside lwd or by the impoundment of water upstream of debris dams due to the high density of hardwood timber species debris dams however do not readily form in tonghi creek as the timber is difficult to transport and lwd usually sinks to the bed of the stream despite the high degree of

physical properties of the mars exploration rover landing sites as inferred from mini tes derived thermal inertia 1 the miniature thermal emission spectrometer mini tes on board the two mars exploration rovers provides the first opportunity to observe thermal properties from the martian surface relate these properties to orbital data and perform soil conductivity experiments under martian conditions the thermal inertias of soils bedforms and rock at each landing site were derived to quantify the physical properties of these features and understand geologic processes occurring at these localities the thermal inertia for the gusev plains rock target bonneville beacon 1200 j m 2 k 1 s 1 2 is consistent with a dense basaltic rock but the rocks at the columbia hills have a lower thermal inertia 620 j m 2 k 1 s 1 2 suggesting that they have a volcaniclasic origin bedforms on the floors of craters at both landing sites have thermal inertias of 200 j m 2 k 1 s 1 2 consistent with a particle diameter of 160 m this diameter is comparable to the most easily moved grain size in the current atmosphere on mars suggesting that these bedforms may have formed under current atmospheric conditions along the meridiani plains the thermal inertia is lower than that derived from tes and thermal emission imaging system themis orbital data this discrepancy is not well understood mini tes derived thermal inertias at gusev along a 2 5 km traverse follow trends in thermal inertia measured from orbit with tes and themis however along the traverse there are variability and mixing of particle sizes that are not resolved in the orbital thermal inertia data due to meter scale processes that are not identifiable at larger scales

thermophysical properties of the mer and beagle ii landing site regions on mars 1 we analyzed remote sensing observations of the isidis basin gusev crater and meridiani planum landing sites for beagle ii mer a spirit and mer b opportunity spacecraft respectively we emphasized the thermophysical properties using daytime and nighttime radiance measurements from the mars global surveyor mgs thermal emission spectrometer and mars odyssey thermal emission imaging system themis and thermal inertias derived from nighttime data sets themis visible images mgs mars orbiter camera moc narrow angle images and mgs mars orbiter laser altimeter mola data are incorporated as well additionally the remote sensing data were compared with ground truth at the mer sites the isidis basin surface layer has been shaped by aeolian processes and erosion by slope winds coming off of the southern highlands and funneling through notches between massifs in the gusev region surface materials of contrasting thermophysical properties have been interpreted as rocks or bedrock duricrust and dust deposits these are consistent with a complex geological history dominated by volcanic and aeolian processes at meridiani planum the many layers having different thermophysical and erosional properties suggest periodic deposition of differing sedimentological facies possibly related to clast size grain orientation and packing or mineralogy

improved general circulation models of the martian atmosphere from the surface to above 80 km we describe a set of two new generation general circulation models of the martian atmosphere derived from the models we originally developed in the early 1990s the two new models share the same physical parameterizations but use two complementary numerical methods to solve the atmospheric dynamic equations the vertical resolution near the surface has been refined and the vertical domain has been extended to above 80 km these changes are accompanied by the inclusion of state of the art parameterizations to better simulate the dynamical and physical processes near the surface boundary layer scheme subgrid scale topography parameterization etc and at high altitude gravity wave drag in addition radiative transfer calculations and the representation of polar processes have been significantly improved we present some examples of zonal mean fields from simulations using the model at several seasons one relatively novel aspect previously introduced by wilson 1997 is that around northern winter solstice the strong pole to pole diabatic forcing creates a quasi global angular momentum conserving hadley cell which has no terrestrial equivalent within such a cell the coriolis forces accelerate the winter meridional flow toward the pole and induce a strong warming of the middle polar atmosphere down to 25 km this winter polar warming had been observed but not properly modeled until recently in fact thermal inversions are generally predicted above one and often both poles around 60 70 km however the mars middle atmosphere above 40 km is found to be very model sensitive and thus difficult to simulate accurately in the absence of observations

thermal inertia mapping of mars from 60 s to 60 n twenty micrometer brightness temperatures are used to derive the thermal inertia for 81 of the martian surface between latitudes 60 these data were acquired by the two viking infrared thermal mappers in 1977 and 1978 following the two global dust storms of 1977 the spatial resolution used is 2 in latitude by 2 in longitude and the total range in derived inertia is 1 to 15 10 3 cal cm 2 sec 12 k 1 the distribution of thermal inertia is strongly bimodal with all values of thermal inertia less than 4 10 3 cal cm 2 sec 12 k 1 being associated with three disjoint bright regions mostly in the northern hemisphere sufficient dust is raised in global storms to provide fine material adequate to produce these low inertia areas but the specific deposition mechanism has not been defined at the low resolution used no complete exposures of clean rock were found there is some tendency for darker material to be associated with higher thermal inertia although the trend is far from one to one the distribution of high and low inertia areas is sufficiently nonrandom to produce a variation in whole disk brightness temperature with central meridian longitude this variation and the change in surface kinetic temperature associated with dust storms are factors in establishing the whole disk brightness temperature at radio and infrared wavelengths and will be important for those who use mars as a calibration source

hopane derived triterpenoids in soils the occurrence distribution and degradation pathways of hopanoid triterpenes have been studied in thirteen soil samples with varying degrees of biological activity hopanoids were shown to occur in all samples suggesting that they are not only ubiquitous in subaquatic sediments but also in soils hop 22 29 ene was generally predominant in the hydrocarbons whereas the 17 h 21 h bishomohopanoic acid c32 was the major component in the acids the concentrations of hopanes were usually rather low except in acidic peat the distribution in carbon number of hopanes and hopanoic acids showed great similarities with those of moderately oxic subaquatic sediments intact bacteriohopane tetrol widespread in microorganisms and the main precursor of geohopanoids was identified in substantial amounts in a peat exposed to groundwater oscillations

atmospheric imaging results from the mars exploration rovers spirit and opportunity a visible atmospheric optical depth of 0 9 was measured by the spirit rover at gusev crater and by the opportunity rover at meridiani planum optical depth decreased by about 0 6 to 0 7 per sol through both 90 sol primary missions the vertical distribution of atmospheric dust at gusev crater was consistent with uniform mixing with a measured scale height of 11 56 0 62 kilometers the dust s cross section weighted mean radius was 1 47 0 21 micrometers mm at gusev and 1 52 0 18 mm at meridiani comparison of visible optical depths with 9 mm optical depths shows a visible to infrared optical depth ratio of 2 0 0 2 for comparison with previous monitoring of infrared optical depths

high resolution thermal inertia mapping from the mars global surveyor thermal emission spectrometer abstract high resolution thermal inertia mapping results are presented derived from mars global surveyor mgs thermal emission spectrometer tes observations of the surface temperature of mars obtained during the early portion of the mgs mapping mission thermal inertia is the key property controlling the diurnal surface temperature variations and is dependent on the physical character of the top few centimeters of the surface it represents a complex combination of particle size rock abundance exposures of bedrock and degree of induration in this work we describe the derivation of thermal inertia from tes data present global scale analysis and place these results into context with earlier work a global map of nighttime thermal bolometer based thermal inertia is presented at 1 4 per pixel resolution with approximately 63 coverage between 50 s and 70 n latitude global analysis shows a similar pattern of high and low thermal inertia as seen in previous viking low resolution mapping significantly more detail is present in the high resolution tes thermal inertia this detail represents horizontal small scale variability in the nature of the surface correlation with albedo indicates the presence of a previously undiscovered surface unit of moderate to high thermal inertia and intermediate albedo this new unit has a modal peak thermal inertia of 180 250 j m 2 k 1 s 1 2 and a narrow range of albedo near 0 24 the unit covering a significant fraction of the surface typically surrounds the low thermal inertia regions and may comprise a deposit of indurated fine material local 3 km resolution maps are also presented as examples of eolian fluvial and volcanic geology some impact crater rims and intracrater dunes show higher thermal inertias than the surrounding terrain thermal inertia of aeolian deposits such as intracrater dunes may be related to average particle size outflow channels and valleys consistently show higher thermal inertias than the surrounding terrain generally correlations between spatial variations in thermal inertia and geologic features suggest a relationship between the hundred meter scale morphology and the centimeter scale surface layer

mapping the mesospheric co2 clouds on mars mex omega and mex hrsc observations and challenges for atmospheric models this study presents the latest results on the mesospheric co2 clouds in the martian atmosphere based on observations by omega and hrsc onboard mars express we have mapped the mesospheric co2 clouds during nearly three martian years of omega data yielding a cloud dataset of 60 occurrences the global mapping shows that the equatorial clouds are mainly observed in a distinct longitudinal corridor at seasons ls 0 60 and again at and after ls 90 a recent observation shows that the equatorial co2 cloud season may start as early as at ls 330 three cases of mesospheric midlatitude autumn clouds have been observed two cloud shadow observations enabled the mapping of the cloud optical depth 0 01 0 6 with median values of 0 13 0 2 at 1 m and the effective radii mainly 1 3 m with median values of 2 0 2 3 m of the cloud crystals the hrsc dataset of 28 high altitude cloud observations shows that the observed clouds reside mainly in the altitude range 60 85 km and their east west speeds range from 15 to 107 m s two clouds at southern midlatitudes were observed at an altitude range of 53 62 km the speed of one of these southern midlatitude clouds was measured and it exhibited west east oriented speeds between 5 and 42 m s the seasonal and geographical distribution as well as the observed altitudes are mostly in line with previous work the lmd mars global climate model shows that at the cloud altitude range 65 85 km the temperatures exhibit significant daily variability caused by the thermal tides with the coldest temperatures towards the end of the afternoon the gcm predicts the coldest temperatures of this altitude range and the season ls 0 30 in the longitudinal corridor where most of the cloud observations have been made however the model does not predict supersaturation but the gcm predicted winds are in fair agreement with the hrsc measured cloud speeds the clouds exhibit variable morphologies but mainly cirrus type filamented clouds are observed nearly all hrsc observations and most of omega observations in 15 of omega observations clumpy round cloud structures are observed but very few clouds in the hrsc dataset show similar morphology these observations of clumpy cumuliform type clouds raise questions on the possibility of mesospheric convection on mars and we discuss this hypothesis based on convective available potential energy calculations

regional dust deposits on mars physical properties age and history major dust storms on mars play an important role in the deposition and removal of fine dust material thermal radar and visual remote sensing observations provide important constraints on the martian regolith which have been used to determine the location and physical properties of regional dust deposits these deposits are located in three northern equatorial regions tharsis 20 s to 50 n 60 to 190 w arabia 5 s to 30 n 300 to 360 w and elysium 10 to 30 n 210 to 225 w they are covered by fine 2 40 m bright albedo 0 27 particles with fewer exposed rocks and coarse deposits than found elsewhere dust is currently deposited uniformly throughout the equatorial region at a rate of 40 m global storm over geologic time the rate of accumulation may vary from 0 to 250 m yr due to changes in atmospheric conditions produced by orbital variations dust deposited during global storms is subsequently removed only from dark regions resulting in a net accumulation in the low inertia bright regions the thickness of these current dust deposits is 0 1 2 m the thermal inertia places a lower limit of 0 1 m on the thickness of these deposits while the sparse but ubiquitous presence of exposed rocks and the degree of visible mantling indicate that the thickness is less than 5 m dual polarization radar observations of a very rough texture in tharsis are consistent with this model with a 2 m thick dust layer burying most of the surface rocks but permitting radar sampling of the rough subsurface based on their thickness and rate of accumulation the age of these deposits is 105 106 years suggesting a cyclic process of deposition and removal one possible cause may be cyclic variations in the magnitude and location of maximum wind velocities related to variations in mars orbit at present perihelion and maximum wind velocities occur in the south whereas regional dust deposits occur in the north suggesting net transport from south to north orbital parameters oscillate with periods ranging from 5 104 to 106 years the agreement between these periods and the dust deposit age suggests a possible link at different stages in orbit evolution maximum wind velocities will occur in the north with subsequent erosion and redistribution of the accumulated fines based on this model much of the uppermost martian surface is very young and is being continually reworked

themis high resolution digital terrain topographic and thermophysical mapping of gusev crater mars 1 we discuss a new technique to generate high resolution digital terrain models dtms and to quantitatively derive and map slope corrected thermophysical properties such as albedo thermal inertia and surface temperatures this investigation is a continuation of work started by kirk et al 2005 who empirically deconvolved thermal emission imaging system themis visible and thermal infrared data of this area isolating topographic information that produced an accurate dtm surface temperatures change as a function of many variables such as slope albedo thermal inertia time season and atmospheric opacity we constrain each of these variables to construct a dtm and maps of slope corrected albedo slope and albedo corrected thermal inertia and surface temperatures across the scene for any time of day or year and at any atmospheric opacity dtms greatly facilitate analyses of the martian surface and the mola global data set is not finely scaled enough 128 pixels per degree 0 5 km per pixel near the equator to be combined with newer data sets e g high resolution imaging science experiment context camera and compact reconnaissance imaging spectrometer for mars at 0 25 6 and 20 m per pixel respectively so new techniques to derive high resolution dtms are always being explored this paper discusses our technique of combining a set of themis visible and thermal infrared observations such that albedo and thermal inertia variations within the scene are eliminated and only topographic variations remain this enables us to produce a high resolution dtm via photoclinometry techniques that are largely free of albedo induced errors with this dtm themis observations and a subsurface thermal diffusion model we generate slope corrected maps of albedo thermal inertia and surface temperatures in addition to greater accuracy these products allow thermophysical properties to be directly compared with topography

mantled and exhumed terrains in terra meridiani mars 1 hematite bearing deposits in the terra meridiani region of mars constitute the top stratum of a partially eroded layered complex that covers dissected noachian aged cratered terrain the hematite unit consists of dark plains and dunes covering a bright substrate this substrate is fully exposed beyond the borders of the hematite bearing deposit and consists of polygonal ground separated by ridges or valleys together with layered deposits that have been eroded into a variety of landforms the complex is partially covered by a regional scale aeolian mantle that thickens toward the north the hematite bearing stratum exhibits low albedoes pulse widths and intermediate thermal inertias whereas the underlying unit exhibits high values of these parameters both units have spectral emissivity signatures similar to those for the low albedo cratered terrain to the south with the addition of hematite for the top stratum the complex is interpreted to consist of extensive plains forming lava flows and tephra deposits emplaced during an extensional regime and at least partially buried by an aeolian mantle aeolian stripping of the mantle exposed much of the complex and differentially eroded the deposits to produce the landforms existent today exploration of the hematite bearing deposits by the 2003 mars exploration rover opportunity will allow testing of the hypotheses presented since this stratum has been locally reworked into dunes that only partially cover the underlying brighter portion of the complex in particular the rover based measurements will allow us to test the extent to which the unusual remote sensing properties of the units indicate aqueous alteration

water ice at low to midlatitudes on mars 1 in this paper we analyze water ice occurrences at the surface of mars using near infrared observations and we study their distribution with a climate model latitudes between 45 s and 50 n are considered data from the observatoire pour la mineralogie l eau les glaces et l actitite and the compact reconnaissance imaging spectrometer for mars are used to assess the presence of surface water ice as a function of location and season a modeling approach combining the 1 d and 3 d versions of the general circulation model of the laboratoire de meteorologie dynamique de jussieu is developed and successfully compared to observations ice deposits 2 200 m thick are observed during the day on pole facing slopes in local fall winter and early spring ice extends down to 13 latitude in the southern hemisphere but is restricted to latitudes higher than 32 in the north on a given slope the pattern of ice observations at the surface is mainly controlled by the global variability of atmospheric water precipitation and vapor with local ground properties playing a lower role only seasonal surface ice is observed no exposed patches of perennial ground ice have been detected surface seasonal ice is however sensitive to subsurface properties the results presented in this study are consistent with the recent discovery of low latitude subsurface ice obtained through the analysis of co 2 frost

the spatial distribution of rocks on mars abstract the spatial distribution of rocks exposed at the surface of mars has been mapped using viking infrared thermal mapper irtm observations overall there are no regions on the surface of mars at a scale of 1 1 in latitude and longitude that are rock free the modal value of rock abundance is 6 areal coverage with no areas having more than 30 35 rock cover the model developed to determine rock abundance relates the thermal emission in each of the four surface sensing irtm bands to temperature contrasts within the field of view non unit thermal emissivity due to absorption bands in the surface materials and the absorption and scattering of the outgoing energy by atmospheric dust and water ice each of these effects produce characteristic spectral and diurnal signatures allowing them to be separated the temperature contrasts provide a means to determine both the abundance of exposed rocks and the fine component thermal intertia rock abundance alone does not produce the observed variation in bulk thermal inertia of the surface low inertia fine bright surfaces have fewer rocks exposed than do high inertia coarse dark surfaces rock abundance does not correlate well with the rms slope nor reflectivity determined from delay doppler radar measurements there is however a possible correlation between rms slope determined from continuous wave radar observations dual polarization radar measurements which provide the best radar measure of small scale roughness indicate that the tharsis volcanic region is very rough whereas thermal measurements indicate very few rocks and a covering of dust together these observations suggest an approximately 1 m thick mantle of fines covering a very rough subsurface this fine material may be an aeolian deposit of dust storm fallout valles marineris together with several major channels and chaotic terrains have high rock abundances as does the acidalia planitia basin this observed distribution may reflect the initial deposition of coarse material associated with channel formation syrtis major is unique in having a high inertia but a very low rock abundance together with low radar roughness these observations are consistent with mantling of rocks by sand the observed distribution of rocks and fines indicates that aeolian processes both erosional and depositional play a dominant role in shaping the present martian surface

low temperature specific heat capacity measurements and application to mars thermal modeling abstract data returned from martian missions have revealed a wide diversity of surface mineralogies including in geological structures interpreted to be sedimentary or altered by liquid water these terrains are of great interest because of their potential to document the environment at a time when life may have appeared intriguingly martian sedimentary rocks show distinctly low thermal inertia values i e 300 700 jm 2k 1s 1 2 indicative of a combination of low thermal conductivity specific heat capacity and density these low values are difficult to reconcile with their competent bedrock morphologies whereas hundreds of bedrock occurrences interpreted as volcanic in origin have been mapped globally and display thermal inertia values 1200 jm 2k 1s 1 2 bedrock thermal inertia values are generally assumed to be driven by their bulk thermal conductivity which in turn is controlled by their micro and macro physical properties i e degree and style of cementation in the case of detritic rocks horizontal fractures and layering etc and not by their density well known from terrestrial analog measurements and with modest variability or specific heat capacity generally uncharacterized for non basaltic materials below room temperature in this paper we demonstrate that specific heat capacity cannot be a potential cause for the differential thermophysical behavior between magmatic and sedimentary rocks through a series of experimental cp t measurements at 100 350 k using differential scanning calorimetry the results on 20 martian relevant minerals investigated in this work indicate that these materials exhibit very similar specific heats ranging from 0 3 0 7 jg 1k 1 at 100 k to 0 6 1 7 jg 1k 1 at 350 k when used in a martian thermal model this range of cp values translate to very small surface temperature differences indicating that uncertainty in composition and its effect on the specific heat is not a noticeable source of thermal inertia variability for indurated units on mars we therefore conclude that the low thermal inertia value of sedimentary rocks compared to magmatic volcanic rocks is likely due to their low apparent bulk conductivity which bears information on their internal physical structure future work combining the analysis of thermal observations acquired at various local times and seasons will help further characterize this heterogeneity

thermal behavior of horizontally mixed surfaces on mars abstract current methods for deriving thermal inertia from spacecraft observations of planetary brightness temperature generally assume that surface properties are uniform for any given observation or co located set of observations as a result of this assumption and the nonlinear relationship between temperature and thermal inertia sub pixel horizontal heterogeneity may yield different apparent thermal inertia at different times of day or seasons we examine the effects of horizontal heterogeneity on mars by modeling the thermal behavior of various idealized mixed surfaces containing differing proportions of either dust sand duricrust and rock or slope facets at different angles and azimuths latitudinal effects on mixed surface thermal behavior are also investigated we find large several 100 j m 2 k 1 s 1 2 diurnal and seasonal variations in apparent thermal inertia even for small 10 admixtures of materials with moderately contrasting thermal properties or slope angles together with similar results for layered surfaces mellon m t putzig n e 2007 lunar planet sci xxxviii abstract 2184 this work shows that the effects of heterogeneity on the thermal behavior of the martian surface are substantial and may be expected to result in large variations in apparent thermal inertia as derived from spacecraft instruments while our results caution against the over interpretation of thermal inertia taken from median or average maps or derived from single temperature measurements they also suggest the possibility of using a suite of apparent thermal inertia values derived from single observations over a range of times of day and seasons to constrain the heterogeneity of the martian surface

apparent thermal inertia and the surface heterogeneity of mars abstract thermal inertia derivation techniques generally assume that surface properties are uniform at horizontal scales below the footprint of the observing instrument and to depths of several decimeters consequently surfaces with horizontal or vertical heterogeneity may yield apparent thermal inertia which varies with time of day and season to investigate these temporal variations we processed three mars years of mars global surveyor thermal emission spectrometer observations and produced global nightside and dayside seasonal maps of apparent thermal inertia these maps show broad regions with diurnal and seasonal differences up to 200 j m 2 k 1 s 1 2 at mid latitudes 60 s to 60 n and 600 j m 2 k 1 s 1 2 or greater in the polar regions we compared the seasonal mapping results with modeled apparent thermal inertia and created new maps of surface heterogeneity at 5 resolution delineating regions that have thermal characteristics consistent with horizontal mixtures or layers of two materials the thermal behavior of most regions on mars appears to be dominated by layering with upper layers of higher thermal inertia e g duricrusts or desert pavements over fines prevailing in mid latitudes and upper layers of lower thermal inertia e g dust covered rock soils with an ice table at shallow depths prevailing in polar regions less common are regions dominated by horizontal mixtures such as those containing differing proportions of rocks sand dust and duricrust or surfaces with divergent local slopes other regions show thermal behavior that is more complex and not well represented by two component surface models these results have important implications for mars surface geology climate modeling landing site selection and other endeavors that employ thermal inertia as a tool for characterizing surface properties

effects of surface roughness and graybody emissivity on martian thermal infrared spectra slopes are present in martian apparent surface emissivity observations collected by the thermal emission spectrometer tes and the thermal emission imaging system themis these slopes are attributed to misrepresenting the surface temperature either through incorrect assumptions about the maximum emissivity of surface materials or the presumption of a uniform surface temperature within the field of view these incorrect assumptions leave distinct characteristics in the resulting apparent emissivity data that can be used to gain a better understanding of the surface properties surfaces with steep slopes typically have a variable surface temperatures within the field of view that cause distinct and highly variable slopes in apparent emissivity spectra based on the observing conditions these properties are documented on the southwestern flank of apollinaris patera and can be reasonably approximated by modeled data this spectral behavior is associated with extremely rough martian surfaces and includes surfaces south of arsia mons and near warrego valles that also appear to have high slopes in high resolution images surfaces with low maximum values of emissivity have apparent emissivity spectra with more consistent spectral slopes that do not vary greatly based on observing conditions this spectral surface type is documented in terra serenum and is consistent with associated high resolution images that do not indicate the presence of a surface significantly rougher that the surrounding terrain

global distribution of bedrock exposures on mars using themis high resolution thermal inertia 1 we investigate high thermal inertia surfaces using the mars odyssey thermal emission imaging system themis nighttime temperature images 100 m pixel spatial sampling for this study we interpret any pixel in a themis image with a thermal inertia over 1200 j m 2 k 1 s 1 2 as bedrock which represents either in situ rock exposures or rock dominated surfaces three distinct morphologies ranked from most to least common are associated with these high thermal inertia surfaces 1 valley and crater walls associated with mass wasting and high surface slope angles 2 floors of craters with diameters 25 km and containing melt or volcanics associated with larger high energy impacts and 3 intercrater surfaces with compositions significantly more mafic than the surrounding regolith in general bedrock instances on mars occur as small exposures less than several square kilometers situated in lower albedo 350 j m 2 k 1 s 1 2 and relatively dust free dust cover index 0 95 regions however there are instances that do not follow these generalizations most instances are concentrated in the southern highlands with very few located at high latitudes poleward of 45 n and 58 s suggesting enhanced mechanical breakdown probably associated with permafrost overall mars has very little exposed bedrock with only 960 instances identified from 75 s to 75 n with likely 3500 km 2 exposed representing 1 ofthe total surface area these data indicate that mars has likely undergone large scale surface processing and reworking both chemically and mechanically either destroying or masking a majority of the bedrock exposures on the planet

martian surface mineralogy from observatoire pour la mineralogie l eau les glaces et l activite on board the mars express spacecraft omega mex global mineral maps 1 after 2 years of operation the observatoire pour la mineralogie l eau les glaces et l activite omega imaging spectrometer on board mars express has acquired data coverage of the martian surface with spatial resolution varying between 300 m and 4 8 km depending on the pericenter altitude of the spacecraft s elliptical orbit we report the global surface distributions of some minerals using the omega observations in the visible and near infrared vnir wavelength domains 0 35 2 5 m global maps of ferric phases mafic minerals pyroxenes and olivines and hydrated minerals have been derived from spectral parameters the limits of detection in terms of abundance for some minerals of different grain size distributions are given the distribution of pyroxenes is in general agreement with the mineral maps of previous telescopic and space observations the fe3 absorption feature in the visible wavelength region is present everywhere on the surface the spectra of the bright regions compare with anhydrous nanophase ferric oxides terrains with water bearing minerals cover a very small fraction of the martian surface olivine mg rich compositions is detected in more extensive regions of the pyroxene rich zones than previously reported olivine with higher iron content and or larger grain size 100 m is only detected in isolated areas the mineralogy of the northern low albedo regions is discussed in the light of these mineral maps chemical alteration or oxidation during extrusion producing a coating or varnish of anhydrous ferric phases over a dark basaltic surface best accounts for the vnir spectral properties of these regions although a glassy composition resulting from impact is also considered

water in the martian regolith from omega mars express here we discuss one of the current reservoirs of water on mars the regolith and rocks exposed at the surface this reservoir is characterized by the presence of h2o and oh bearing phases that produce a broad absorption at a wavelength of 3 m in near infrared nir reflectance spectra this absorption is present in every ice free spectrum of the martian surface obtained thus far by orbital nir spectrometers we present a quantitative analysis of the global distribution of the 3 m absorption using the observatoire pour la mineralogie l eau les glaces et l activite omega imaging spectrometer that has been mapping the surface of mars at kilometer scale for more than 10 years based on laboratory reflectance spectra of a wide range of hydrous minerals and phases we estimate a model dependent water content of 4 1 wt in the equatorial and midlatitudes surface hydration increases with latitude with an asymmetry in water content between the northern and southern hemispheres the surface hydration is compared to various parameters albedo dust geological units time relative humidity atmospheric water pressure and in situ measurements performed by phoenix and curiosity to constrain the nature of the reservoir we conclude that the nature of the surface hydration of the martian low latitudes is not adsorbed water but rather more tightly bound water molecules and hydroxyl groups in the structure of the materials of the near top surface a frost related process best explains the implementation of water into and onto the first microns of the high latitude martian regolith

global maps of anhydrous minerals at the surface of mars from omega mex 1 we here reassess the global distribution of several key mineral species using the entire omega mars express vis nir imaging spectrometer data set acquired from orbit insertion in january 2004 to august 2010 thirty two pixels per degree global maps of ferric oxides pyroxenes and olivines have been derived a significant filtering process was applied in order to exclude data acquired with unfavorable observation geometries or partial surface coverage with water and co2 frosts because of strong atmospheric variations over the 3 6 martian years of observations primarily due to the interannual variability of the aerosol opacity a new filter based on the atmospheric dust opacity calibrated by the mars exploration rovers measurements has also been implemented the fe3 absorption features are present everywhere on the surface with a variety of intensities indicating distinct formation processes the pyroxene bearing regions are localized in low albedo regions while the bright regions are spectrally comparable to anhydrous nanophase ferric oxides the expanded data set increases by a factor of about 2 the number of olivine detections reported in previous omega based studies olivine is mainly detected in three types of areas over the martian surface discontinuous patches on the terraces of the three main basins smooth inter crater plains and smooth crater floors throughout the southern highlands and crater sand dunes crater ejectas and extended bedrock exposures in the northern plains olivine is also detected in the low albedo pyroxene bearing dunes surrounding the northern polar cap

properties of a martian local dust storm in atlantis chaos from omega mex data abstract in this study we present the analysis of the dust properties of a local storm imaged in the atlantis chaos region on mars by the omega imaging spectrometer on march 2nd 2005 we use the radiative transfer model mitra to study the dust properties at solar wavelengths between 0 5 m and 2 5 m and infer the connection between the local storm dynamics and the topography we retrieve maps of effective grain radius reff optical depth at 9 3 m 9 3 and top altitude ta of the dust layer our results show that large particles reff 1 6 m are gathered in the centre of the storm lat 33 5 s lon 183 5 w where the optical depth is maximum 9 3 7 0 and the top altitude exceeds 18 km outside the storm we obtain 9 3 we speculate that a low thermal inertia region at the western border of atlantis chaos is a possible source of the dust storm moreover we find evidence that topography plays a role in confining the local storm in atlantis chaos the vertical wind component from the gcm does not provide any hint for the triggering of dust lifting on the other hand the combination of the horizontal and vertical wind profiles suggests that the dust once lifted is pushed eastward and then downward and gets confined within the north east ridge of atlantis chaos from our results the thickness of the dust layer collapsed on the surface ranges from about 1 m at the storm boundaries up to more than 100 m at its centre we verify that a layer of dust thicker than 1 m deposited on the surface can prevent the detection of mafic absorption features however such features are still present in omega data of atlantis chaos registered after the storm hence we deduce that once the storm is over the dust deposited on an area larger than the one where it has been observed

derivation of martian surface slope characteristics from directional thermal infrared radiometry abstract directional thermal infrared measurements of the martian surface is one of a variety of methods that may be used to characterize surface roughness and slopes at scales smaller than can be obtained by orbital imagery thermal emission spectrometer tes emission phase function epf observations show distinct apparent temperature variations with azimuth and emission angle that are consistent with the presence of warm sunlit and cool shaded slopes at typically 0 1 m scales a surface model of a gaussian distribution of azimuth independent slopes described by bar is combined with a thermal model to predict surface temperature from each viewing angle and azimuth of the tes epf observation the models can be used to predict surface slopes using the difference in measured apparent temperature from 2 separate 60 70 emission angle observations taken 180 in azimuth relative to each other most martian surfaces are consistent with low to moderate slope distributions the slope distributions display distinct correlations with latitude longitude and albedo exceptionally smooth surfaces are located at lower latitudes in both the southern highlands as well as in high albedo dusty terrains high slopes are associated with southern high latitude patterned ground and north polar sand dunes there is little apparent correlation between high resolution imagery and the derived bar with exceptions such as duneforms this method can be used to characterize potential landing sites by assuming fractal scaling behavior to meter scales more precisely targeted thermal infrared observations from other spacecraft instruments are capable of significantly reducing uncertainty as well as reducing measurement spot size from 10s of kilometers to sub kilometer scales

remote sensing of surface pressure on mars with the mars express omega spectrometer 2 meteorological maps 1 surface pressure measurements help to achieve a better understanding of the main dynamical phenomena occurring in the atmosphere of a planet the use of the mars express omega visible and near ir imaging spectrometer allows us to tentatively perform an unprecedented remote sensing measurement of martian surface pressure omega reflectances in the co2 absorption band at 2 m are used to retrieve a hydrostatic estimation of surface pressure see companion paper by forget et al 2007 with a precision sufficient to draw maps of this field and thus analyze meteorological events in the martian atmosphere prior to any meteorological analysis omega observations have to pass quality controls on insolation and albedo conditions atmosphere dust opacity and occurrence of water ice clouds and frosts for the selected observations registration shifts with the mola reference are corrected sea level surface pressure reduction is then carried out in order to remove the topographical component of the surface pressure field three main phenomena are observed in the resulting omega surface pressure maps horizontal pressure gradients atmospheric oscillations and pressure perturbations in the vicinity of topographical obstacles the observed pressure oscillations are identified as possible signatures of phenomena such as inertia gravity waves or convective rolls the pressure perturbations detected around the martian hills and craters may be the signatures of complex interactions between an incoming flow and topographical obstacles highly idealized mesoscale simulations using the wrf model enable a preliminary study of these complex interactions but more realistic mesoscale simulations are necessary the maps provide valuable insights for future synoptic and mesoscale modeling which will in turn help in the interpretation of observations

three decades of martian surface changes 1 the surface of mars has changed dramatically during the three decades spanned by spacecraft exploration comparisons of mars global surveyor images with viking and mariner 9 pictures suggest that more than one third of mars surface area has brightened or darkened by at least 10 such albedo changes could produce significant effects on solar heating and the global circulation of winds across the planet all of the major changes took place in areas of moderate to high thermal inertia and rock abundance consistent with burial of rocky surfaces by thin dust layers deposited during dust storms and subsequent exposure of the rocky surfaces by aeolian erosion several distinct mechanisms contribute to aeolian erosion on mars prevailing winds dominate erosion at low latitudes producing diffuse albedo boundaries and elongated wind streaks generally oriented in the direction of southern summer winds dust devils darken the mid to high latitudes from 45 to 70 degrees during the summer seasons forming irregular albedo patterns consisting of dark linear tracks dust storms produce regional albedo variations with distinct but irregular margins dark sand dunes in southern high latitudes appear to be associated with regional darkening that displays diffuse albedo boundaries no surface changes were observed to repeat regularly on an annual basis but many of the changes took place in areas that alternate episodically between high and low albedo states as thin mantles of dust are deposited and later stripped off hence the face of mars remains recognizable after a century of telescopic observations in spite of the enormous extent of alteration that has taken place during the era of spacecraft exploration

temperature dependent thermal inertia of homogeneous martian regolith 1 past studies of the thermophysical properties of the martian surface layer have assumed temperature independent thermal inertia which is a function of the material density specific heat and bulk conductivity in this paper we evaluate the temperature driven variations of these quantities for particulated and cemented material under martian conditions of atmospheric pressure and temperature temperature driven density variations are negligible the specific heat of a basaltic material is strongly influenced by the temperature 75 increase from 150 to 315 k inducing significant variations of the thermal inertia the thermal conductivity of uncemented martian regolith is weakly controlled by the solid phase conductivity and strongly controlled by the gaseous phase conductivity as a result the conductivity of the solid phase i e composition temperature is unimportant whereas medium to large variations 30 50 of the bulk conductivity are associated with temperature induced fluctuations of the pore filling gas conductivity overall the thermal inertia of uncemented martian soils is predicted to vary significantly 80 throughout the range of the observed surface temperatures in the case of cemented soils the contribution of the gas conductivity is generally small and the solid phase i e grains and cement conductivity i e composition temperature becomes more important consequently the magnitude of the thermal inertia change for cemented soils is variable and smaller than that predicted for uncemented materials 10 50 large diurnal and seasonal temperature variations only occur within the top material and most of the near surface regolith does not experience large thermal inertia variations the shapes of modeled diurnal temperature curves are not significantly modified e g the 0200 lt martian local time apparent thermal inertia of uncemented regolith is up to 15 lower than the average daily inertia of the top material thermally derived grain sizes are usually based on conductivity measurements operated at room temperature or above where the thermal inertia and specific heat are higher than on mars implying that grain size predictions for mars are currently underestimated however in situ observations by the mars exploration rovers and thermal conductivity modeling suggest that this underestimation is not significant

mars surface thermal inertia and heterogeneities from omega mex abstract the thermophysical structure of the martian surface is the result of various processes that have shaped the martian surface through time previous dedicated heliosynchronous measurements of the thermal infrared ir flux of the martian surface have revealed the diversity of martian surface thermal properties as well as its complexity linked to the heterogeneous nature of terrains we present the first retrieval of thermophysical properties of the martian surface using near infrared nir observatoire pour la mineralogie l eau les glaces et l activite omega onboard mars express mex thermal measurements from 5 to 5 1 m mex orbit around mars is elliptical and therefore omega has performed surface temperature measurements at various local times and seasons over more than 4 full martian years we have developed a method to exploit these unprecedented measurements using a one dimensional energy balance code derived from a global climate model that allows retrieval of the thermal properties of the martian surface using omega data regional maps of the thermal inertia at a resolution up to 32 pixels per degree and a global map at 4 pixels per degree are presented omega derived thermal inertia values agree with previous mappings by the thermal emission spectrometer tes onboard mars global surveyor mgs and thermal emission imaging spectrometer themis onboard mars odyssey and highlight the key role of dust for the thermal behavior of the martian surface omega directly reveals for the first time some diurnal variations of apparent ti attributable to surface heterogeneities at macroscopic scale and enables to quantify these heterogeneities in nili patera and tharsis local surface heterogeneities are modeled with layering and horizontal admixture of divergent slopes respectively