cross season relation of the south china sea precipitation variability between winter and summer the present study reveals cross season connections of rainfall variability in the south china sea scs region between winter and summer rainfall anomalies over northern south china sea in boreal summer tend to be preceded by the same sign rainfall anomalies over southern south china sea in boreal winter denoted as in phase relation and succeeded by opposite sign rainfall anomalies over southern south china sea in the following winter denoted as out of phase relation analysis shows that the in phase relation from winter to summer occurs more often in el nino la nina decaying years and the out of phase relation from summer to winter appears more frequently in el nino la nina developing years in the summer during the el nino la nina decaying years cold warm and warm cold sea surface temperature sst anomalies develop in tropical central north pacific and the north indian ocean respectively forming an east west contrast pattern the in phase relation is associated with the influence of anomalous heating cooling over the equatorial central pacific during the mature phase of el nino la nina events that suppresses enhances precipitation over southern south china sea and the impact of the above east west sst anomaly pattern that reduces increases precipitation over northern south china sea during the following summer the impact of the east west contrast sst anomaly pattern is confirmed by numerical experiments with specified sst anomalies in the el nino la nina developing years regional air sea interactions induce cold warm sst anomalies in the equatorial western north pacific the out of phase relation is associated with a rossby wave type response to anomalous heating cooling over the equatorial central pacific during summer and the combined effect of warm cold sst anomalies in the equatorial central pacific and cold warm sst anomalies in the western north pacific during the mature phase of el nino la nina events

spectral mixture modeling a new analysis of rock and soil types at the viking lander 1 site a viking lander 1 image was modeled as mixtures of reflectance spectra of palagonite dust gray andesitelike rock and a coarse rocklike soil the rocks are covered to varying degrees by dust but otherwise appear unweathered rocklike soil occurs as lag deposits in deflation zones around stones and on top of a drift and as a layer in a trench dug by the lander this soil probably is derived from the rocks by wind abrasion and or spallation dust is the major component of the soil and covers most of the surface the dust is unrelated spectrally to the rock but is equivalent to the global scale dust observed telescopically a new method was developed to model a multispectral image as mixtures of end member spectra and to compare image spectra directly with laboratory reference spectra the method for the first time uses shade and secondary illumination effects as spectral end members thus the effects of topography and illumination on all scales can be isolated or removed the image was calibrated absolutely from the laboratory spectra in close agreement with direct calibrations the method has broad applications to interpreting multispectral images including satellite images

sst anomalies of enso and the madden julian oscillation in the equatorial pacific this study explores whether anomalies of sea surface temperature sst in the equatorial pacific during warm events of el nino southern oscillation enso are related to the madden julian oscillation mjo an index is derived from surface wind data of a global model reanalysis to measure forcing of oceanic kelvin waves by wind stress associated with the mjo this kelvin wave forcing index of the mjo is used to relate interannual anomalies in seasonal activity of the mjo to interannual anomalies in equatorial sst for the 1980 99 time period evidence is found showing that during enso warm events stronger kelvin wave forcing in the western pacific precedes greater sst anomalies in the eastern pacific by 6 12 months no such evidence however can be found for the period of 1950 79 the result suggests that during enso warm events amplitudes of sst anomalies in the eastern pacific can be affected by the mjo at least for the 1980 99 period through its seasonal activity of kelvin wave forcing a possible mechanism for such an mjo enso relationship is described how enso prediction can be benefited from the precursory signals of the mjo is discussed

effects of intraseasonal oscillation on south china sea summer monsoon onset understanding of south china sea scs summer monsoon scssm onset response to tropical intraseasonal oscillation iso is critical for extended range prediction of scssm onset in this study we investigate the effect of iso on scssm onset for the period of 1980 2013 the 34 onset cases are classified into three groups early onsets around may 6th normal onsets around may 21st and late onsets around june 8th and the late onsets are even later than the indian monsoon onsets before each onset the scs experiences a dry iso phase to precondition the convective energy due to the easterly wind anomalies of the wet iso phase over the tropical indian ocean for the group of early onsets over the southern bay of bengal monsoon region for the group of normal onsets and over the southern indian monsoon region for the group of late onsets after each onset the scssm is supported by the westerly wind anomalies of the dry iso phase over these associated regions each early scssm onset is triggered by the northwestward propagating rossby wave of the wet iso in the western pacific which comes from the indian ocean for each normal late onset the scssm is triggered by synoptic scale low level westerlies in conjunction with seasonal low level westerlies when the wet iso moves to the northern bay of bengal region indian monsoon region since this convection to the north of 10 n cannot excite the easterly wind anomalies associated with kelvin wave responses over the scs to suppress the convection the mechanisms explaining the mean state controlled iso scssm onset relationship are also discussed

viking landing sites remote sensing observations and physical properties of martian surface materials abstract important problems that confront future scientific exploration of mars include the physical properties of martian surface materials and the geologic processes that formed the materials the design of landing spacecraft roving vehicles and sampling devices and the selection of landing sites vehicle traverses and sample sites will be in part guided by the physical properties of the materials four materials occur in the sample fields of the viking landers 1 drift 2 crusty to cloddy 3 blocky and 4 rock the first three are soillike drift materials is weak loose and porous we estimate that it has a dielectric constant near 2 4 and a thermal inertia near 1 10 3 to 3 10 3 cal cm 2 sec 1 2 k 1 because of its low bulk density fine grain size and small cohesion crusty to cloddy material is expected to have a dielectric constant near 2 8 and a thermal inertia near 4 10 3 to 7 10 3 because of its moderate bulk density and cementation of grains blocky material should have a dielectric constant near 3 3 and a thermal inertia near 7 10 3 to 9 10 3 because of its moderate bulk density and cementation common basaltic rocks have dielectric constans near 8 and thermal inertias near 30 10 3 to 60 10 3 comparisons of estimated dielectric constants and thermal inertias of the materials at the landing sites with those obtained remotely by earth based radars and viking orbiter thermal sensors suggest that the materials at the landing sites are good analogs for materials elsewhere on mars correlation of remotely estimated dielectric constant and thermal inertias indicates two modal values for paired values of dielectric constants and thermal inertias near a 2 and 2 10 3 and b 3 and 6 10 3 respectively these two modes are comparable to the dielectric constants and thermal inertias for drift and crusty to cloddy material respectively dielectric constants and thermal inertias for blocky material are larger but conistent with values in the northern plains our interprertations are compatible with an aeolian origin for drift and similar materials elsewhere on mars the postulate that moderate dielectric constants and thermal inertias larger than 3 or 4 10 3 are produced by cementation of soillike materials is partly consistent with the data the average dielectric constant and thermal inertia and their correlation with one another suggest that most of the surface of mars should present few difficulties to future surface exploration but some surfaces may present difficulties for spacecraft that are not suitably designed

indian ocean capacitor effect on indo western pacific climate during the summer following el nino significant climate anomalies persist through the summer june august after el nino dissipates in spring over the equatorial pacific they include the tropical indian ocean tio sea surface temperature sst warming increased tropical tropospheric temperature an anomalous anticyclone over the subtropical northwest pacific and increased mei yu baiu rainfall over east asia the cause of these lingering el nino effects during summer is investigated using observations and an atmospheric general circulation model gcm the results herein indicate that the tio warming acts like a capacitor anchoring atmospheric anomalies over the indo western pacific oceans it causes tropospheric temperature to increase by a moist adiabatic adjustment in deep convection emanating a baroclinic kelvin wave into the pacific in the northwest pacific this equatorial kelvin wave induces northeasterly surface wind anomalies and the resultant divergence in the subtropics triggers suppressed convection and the anomalous anticyclone the gcm results support this kelvin wave induced ekman divergence mechanism in response to a prescribed sst increase over the tio the model simulates the kelvin wave with low pressure on the equator as well as suppressed convection and the anomalous anticyclone over the subtropical northwest pacific an additional experiment further indicates that the north indian ocean warming is most important for the kelvin wave and northwest pacific anticyclone a result corroborated by observations these results have important implications for the predictability of indo western pacific summer climate the spatial distribution and magnitude of the tio warming rather than simply whether there is an el nino in the preceding winter affect summer climate anomalies over the indo western pacific and east asia

a radar study of the chryse region mars arecibo 12 6 cm delay doppler measurements are used to study the topography and radar scattering properties of the chryse region including the viking 1 and mars pathfinder lander sites and environs the viking 1 lander lies on a gentle 0 13 east facing slope at a 6 1 mbar altitude of 1 35 km the mars pathfinder lander site lies slightly lower 1 7 km on a flat low relief plain quasi specular roughness across chryse is considerably higher than the martian average and shows some strong spatial variation not apparent from older cw observations some of the rougher regions coincide with the distal ends of the tiu and ares vallis channels while another is located just to the northeast of the viking 1 lander chryse shows asymmetric scattering skew similar to that seen in mars southern hemisphere and in recent magellan radar observations of venus comparison of 12 6 cm and 3 5 cm data indicates that chryse s quasi specular reflectivity is strongly wavelength dependent being higher at the longer wavelength suggesting a rapid density increase within the top decimeter of the regolith depolarized reflectivity images of the general chryse area show modest enhancements from decimeter scale roughness or rocks associated with maja and kasei valles and the plateau bordering simud vallis these images indicate that the rock abundance at the proposed mars pathfinder lander site is similar to that at the viking lander sites

contrast of 10 20 day and 30 60 day intraseasonal sst propagation during summer and winter over the south china sea and western north pacific this study documents the structure and propagation of intraseasonal sea surface temperature sst variations and relative contribution of surface latent heat flux and shortwave radiation to the sst propagation in the south china sea scs and western north pacific wnp regions the emphasis is on the contrast of intraseasonal sst propagation between summer and winter and between 10 20 day and 30 60 day time scales the dominant sst pattern during summer displays a tilted southwest northeast band from the scs to the subtropical wnp on both time scales but with a larger value in the subtropical wnp on the 10 20 day time scale and in the scs on the 30 60 day time scale the dominant sst pattern during winter resembles that during summer but with a larger value in the scs in summer the sst anomalies show obvious northwestward and northward propagations in the scs wnp region on the 10 20 day and 30 60 day time scales respectively the cloud radiation effect is a dominant factor for the sst propagation on both time scales in the scs wnp region with a supplementary effect from the wind evaporation effect on the 10 20 day time scale in winter the sst anomalies show southward propagation on both time scales in the scs while the southward propagation in the wnp is weak and confined to the subtropics on the 10 20 day time scale the wind evaporation effect makes a larger contribution to the sst propagation than the cloud radiation effect on both time scales in the scs wnp region

evolution of the madden julian oscillation in two types of el nino abstractevolution characteristics of the madden julian oscillation mjo during the eastern pacific ep and central pacific cp types of el nino have been investigated mjo activities are strengthened over the western pacific during the predeveloping and developing phases of ep el nino but suppressed during the mature and decaying phases in contrast mjo activities do not show a clear relationship with cp el nino before their occurrence over the western pacific but they increase over the central pacific during the mature and decaying phases of cp el nino lag correlation analyses further confirm that mjo activities over the western pacific in boreal spring and early summer are closely related to ep el nino up to 2 11 months later but not for cp el nino ep el nino tends to weaken the mjo and lead to a much shorter range of its eastward propagation anomalous descending motions over the maritime continent and western pacific related to el nino can suppress convection and moisture flux convergence the

global duricrust on mars analysis of remote sensing data global remote sensing data for mars are analyzed to obtain a simple self consistent model for the surface layer the data sets discussed include radar cross section measurements at several wavelengths radio whole disk thermal emission observations at two wavelengths the global distribution of thermal inertia deviations of diurnal temperatures from those of a homogeneous model and thermal spectral estimates of surface rock abundance and of the thermal inertia of the nonrocky component of the surface the data sets which most constrain the interpretation are the rock abundance map and the correlation of thermal inertia with radar cross section these require the rock abundance to not vary significantly from place to place and simultaneously require the density and thermal inertia of the fines to vary in a consistent manner the simplest model which can explain all of the data involves a global case hardened crust duricrust which varies spatially in its degree of formation in general low thermal inertia regions have a poorly developed crust and highinertia regions have a well developed crust there are however regions that consist of coarse particles and which do not fit this model e g chryse this model is consistent with the ages of low inertia regions and with aeolian mechanisms for their development the duricrust is thought to form via the mobilization of salt ions within a layer of water adsorbed within the regolith and its formation may be associated with the exchange of water between the regolith and atmosphere which occurs on the 105 and 106 year time scale

factors for interannual variations of september october rainfall in hainan china the present study investigates the year to year variations of september october rainfall in hainan china for the period 1965 2010 the dominant circulation anomalies feature a cyclone an anticyclone over the indochina peninsula and northern south china sea an anticyclone a cyclone over subtropical western north pacific and lower level convergence divergence over the maritime continent in the wet dry years these circulation anomalies are responses to an east west sea surface temperature sst anomaly pattern withnegative positive sst anomaliesin theequatorialcentralpacificandpositive negative sstanomalies around the maritime continent in the wet dry years although the sst anomaly pattern is similar but with opposite anomaly the sst signal in the equatorial central pacific is more significant in the dry years than in the wet years this difference indicates a larger case to case variability in the wet years than in the dry years thelargevariabilityinthewetyearsisattributedtocontributionsoftropicalcyclones tcs andintraseasonal oscillations isos there are more tcs impinging on hainan and the tc tracks are closer to the island in the wet years than in the dry years the rainfall shows large intraseasonal variations with periods of 10 20 and 30 60 days during september october in the wet years the 10 20 day iso originates from the maritime continent whereas the 30 60 day iso develops over tropical indian ocean and propagates northeastward to northern south china sea in contrast the iso signal is much weaker in the dry years

early silurian radiolaria from northern nevada usa abstract radiolarians recovered from three sites in the early llandoverian cherry spring chert north central nevada provide the first early silurian radiolarian data from the conterminous united states two assemblages were recovered that contain abundant pylomate sphaerellarians rotasphaerids inaniguttids and possible palaeoactinosphaerids the pylomate taxa have an intermediate spine morphology with cessipylorum and aciferopylorum bringing into question the present criteria for distinguishing these two genera rotasphaerids include both species of rotasphaera and secuicollacta that have five primary rods per spine unit similar to those present in ordovician assemblages caradocian ashgillian reported from nevada and australia oriundogutta is another common component shared between the cherry spring and caradocian ashgillian age faunas to a lesser extent the cherry spring fauna resembles late early late silurian wenlockian ludlovian assemblages that contain abundant inaniguttids and rotasphaerids none of the younger species of inaniguttids have been recognized however and younger species of rotasphaerids differ in that they have six primary rods per spine unit and a more diverse spine morphology these preliminary data indicate a stronger similarity between late ordovician and early llandoverian assemblages than between early llandoverian and wenlockian ludlovian assemblages the cherry spring chert faunas contain several distinct forms such as cessipylorum sp a and b that may prove useful for biostratigraphic correlation

rocks and aeolian features in the mars pathfinder landing site region viking infrared thermal mapper observations albedo rock abundance and thermal inertia derived from viking infrared thermal mapper observations provide information about the surface materials within the mars pathfinder landing ellipse in ares vallis relative to the rest of mars the site has an intermediate albedo 0 19 0 23 intermediate to high bulk thermal inertia 410 540 j m 2 s 0 5 k 1 and high rock abundance 18 25 at local scales the actual surface distribution of rocks might be heterogeneous as on terrestrial catastrophic flood surfaces where rocks tend to be concentrated on fluvially armored surfaces and or bars albedo increases and thermal inertia decreases from the northeast to the southwest in the ellipse owing to interpreted windblown dark sand from acidalia planitia if mars pathfinder lands at the southwest end of the landing ellipse the scene is likely to be the most similar to that of the viking 1 lander while a landing at the northeast end of the ellipse is most likely to provide a view that is different from the viking sites because of low albedo material a landing at the center of the ellipse might put the spacecraft near one of two crater clusters that are interpreted to have dark sandy material in or on their ejecta aeolian activity during the 30 day primary mission might be limited because it is mid northern summer a time in which no historic dust storms have been seen in the region and a season when regional winds should be weak relative to other times during the year

an observational study of the south china sea monsoon during the 1979 summer onset and life cycle abstract the onset and life cycle of the 1979 south china sea summer monsoon were examined in the context of the 30 60 and 12 24 day monsoon modes the former intraseasonal mode formed the northward migrating monsoon trough ridge while the latter intraseasonal mode propagated westward in the south china sea the monsoon in this region exhibited three cycles over the summer may august with the onset taking place about one cycle ahead of the onset of the indian and japanese monsoons climatologically a summer trough line radiated out from the indian monsoon trough region across indochina to the northern south china sea the monsoon onset occurred when the 30 60 day monsoon trough and the 12 24 day low center arrived simultaneously at the northern south china sea close to the climatological summer trough line in the middle of may the breaks occurred when the 30 60 day monsoon ridge lines and the 12 24 day high center met near 15 20 n in the northern south china sea the south china sea monsoon wa

the imager for mars pathfinder experiment the imager for mars pathfinder imp a stereoscopic multispectral camera is described in terms of its capabilities for studying the martian environment the camera s two eyes separated by 15 0 cm provide the camera with range finding ability each eye illuminates half of a single ccd detector with a field of view of 14 4 14 0 and has 12 selectable filters the 18 optics have a large depth of field and no focussing mechanism is required a mechanical shutter is avoided by using the frame transfer capability of the 512 512 ccd the resolving power of the camera 0 98 mrad pixel is approximately the same as the viking lander cameras however the signal to noise ratio for imp greatly exceeds viking approaching 350 this feature along with the stable calibration of the filters between 440 and 1000 nm distinguishes imp from viking specially designed targets are positioned on the lander they provide information on the magnetic properties of wind blown dust measure the wind vectors and provide radiometric standard reflectors for calibration also eight low transmission filters are included for imaging the sun directly at multiple wavelengths giving imp the ability to measure dust opacity and potentially the water vapor content several experiments beyond the requisite color panorama are described in detail contour mapping of the local terrain multispectral imaging of the surrounding rock and soil to study local mineralogy viewing of three wind socks measuring atmospheric opacity and water vapor content and estimating the magnetic properties of wind blown dust this paper is intended to serve as a guide to understanding the scientific integrity of the imp data that will be returned from mars starting on july 4 1997

relationship of boreal summer 10 20 day and 30 60 day intraseasonal oscillation intensity over the tropical western north pacific to tropical indo pacific sst the present study contrasts interannual variations in the intensity of boreal summer 10 20 day and 30 60 day intraseasonal oscillations isos over the tropical western north pacific and their factors a pronounced difference is found in the relationship of the two isos to el nino southern oscillation the 10 20 day iso intensity is enhanced during el nino developing summer whereas the 30 60 day iso intensity is enhanced during la nina decaying summer the above different relationship is interpreted as follows the equatorial central and eastern pacific sst anomalies modify vertical wind shear lower level moisture and vertical motion in a southeast northwest oriented band from the equatorial western pacific to the tropical western north pacific where the 10 20 day isos originate and propagate these background field changes modulate the amplitude of 10 20 day isos preceding equatorial central and eastern pacific sst anomalies induce sst anomalies in the north indian ocean in summer which in turn modify vertical wind shear and vertical motion over the tropical western north pacific the modified background fields influence the amplitude of the 30 60 day isos when they reach the tropical western north pacific from the equatorial region a feedback of iso intensity on local sst change is identified in the tropical western north pacific likely due to a net effect of isos on surface heat flux anomalies this feedback is more prominent from the 10 20 day than the 30 60 day iso intensity change

influences of northward propagating 25 90 day and quasi biweekly oscillations on eastern china summer rainfall the present study reveals that rainfall anomalies associated with the 25 90 day quasi biweekly tropical convective activity propagates northward northwestward into northern china the yangtze river enhanced rainfall over southern china results directly from enhanced convection propagating northward from the south china sea scs western north pacific wnp strengthened northward water vapor transport and intensified upper level divergence the anomalous anticyclone over scs wnp which is induced by local lower sea surface temperature provides a favorable condition for transporting more moisture to southern china stronger subtropical westerly jet and south asia high strengthen upper level divergence the northward propagating 25 90 day oscillation over eastern china reaches farther north than the quasi biweekly oscillation qbwo the intensity of qbwo in summer rainfall has significantly strengthened over southern china after 1993 but not for the 25 90 day oscillation this is mainly contributed by an interdecadal increase in rainfall over southern china and the yangtze river basin in the wet phases of qbwo the interdecadal enhancement of rainfall associated with the qbwo is attributed to three factors one is lower tropospheric convergence caused by anomalous anticyclone over the wnp and anomalous cyclone over korean peninsula and japan the second is upper tropospheric divergence resulting from strengthening of subtropical westerly jet and the south asia high the last is enhanced ascent over south china through meridional vertical circulation

selection of the mars pathfinder landing site the mars pathfinder spacecraft will land on a depositional fan near the mouth of the catastrophic outflow channel ares vallis 19 5 n 32 8 w this site offers the prospect of analyzing a variety of rock types from the ancient cratered highlands intermediate age ridged plains and reworked channel deposits analyses of these rocks by pathfinder instruments will enable first order scientific questions to be addressed such as differentiation of the crust the development of weathering products and the nature of the early environment as well as their subsequent evolution on mars constraints imposed by 1 spacecraft and rover designs which are robust 2 entry descent and landing 3 scientific potential at various sites and 4 safety were important considerations in site selection engineering constraints require a 70 km by 200 km smooth flat low slopes area located between 10 and 20 n that is below 0 km elevation with average radar reflectivity little dust and moderate rock abundance three regions on mars are between 10 and 20 n and below 0 km elevation chryse amazonis and isidis elysium science considerations favor sites at the mouths of outflow channels grab bag sites offer an assay of rock types on mars highland sites early crustal differentiation and climate and sites covered with dark unoxidized material sites are considered safe if they are clearly below 0 km elevation appear acceptably free of hazards in high resolution 50 m pixel viking orbiter images and have acceptable reflectivity and roughness at radar wavelengths thermal inertia rock abundance red to violet ratio and albedo recent 3 5 cm wavelength radar observations were used to verify elevation reflectivity and roughness within the landing ellipses three sites meet all of these criteria ares vallis tritonis lacus and isidis although isidis appears to be safer than tritonis and ares the greater scientific potential at ares vallis resulted in its selection comparisons of the grand coulee channel and the depositional ephrata fan of the channeled scabland in eastern washington with ares vallis and its depositional fan also suggest the ares vallis landing site is safe and scientifically interesting

a model for the boreal summer intraseasonal oscillation abstract the tropical intraseasonal oscillation iso exhibits pronounced seasonality the boreal summer iso is more complex than its winter counterpart due to the coexistence of equatorial eastward off equatorial westward and northward propagating low frequency modes and their interactions based on observational evidence and results obtained from numerical experiments a mechanism is proposed for the boreal summer iso in which the northern hemisphere summer monsoon nhsm circulation and moist static energy distribution play essential roles with a climatological july mean basic state the life cycle of model low frequency waves consists of four processes an equatorial eastward propagation of a coupled kelvin rossby wave packet an emanation of moist rossby waves in the western pacific a westward propagation and amplification of the rossby waves in south asian monsoon regions and a reinitiation of the equatorial disturbances over the central indian ocean the life cycle spans about one month and p

multi stage onset of the summer monsoon over the western north pacific the climatological summer monsoon onset displays a distinct step wise northeastward movement over the south china sea and the western north pacific wnp 110 160 e 10 20 n monsoon rain commences over the south china sea philippines region in mid may extends abruptly to the southwestern philippine sea in early to mid june and finally penetrates to the northeastern part of the domain around mid july in association three abrupt changes are identified in the atmospheric circulation specifically the wnp subtropical high displays a sudden eastward retreat or quick northward displacement and the monsoon trough pushes abruptly eastward or northeastward at the onset of the three stages the step wise movement of the onset results from the slow northeastward seasonal evolution of large scale circulation and the phase locked intraseasonal oscillation iso the seasonal evolution establishes a large scale background for the development of convection and the iso triggers deep convection the iso over the wnp has a dominant period of about 20 30 days this determines up the time interval between the consecutive stages of the monsoon onset from the atmospheric perspective the seasonal sea surface temperature sst change in the wnp plays a critical role in the northeastward advance of the onset the seasonal northeastward march of the warmest sst tongue sst exceeding 29 5 c favors the northeastward movement of the monsoon trough and the high convective instability region the seasonal sst change in turn is affected by the monsoon through cloud radiation and wind evaporation feedbacks

interannual variability of summer monsoon onset over the western north pacific and the underlying processes climatological summer monsoon onset over the south china sea scs and the western north pacific wnp defined as the region of 108 208n 1208 1608e displays three distinct stages around mid may monsoon rain commences in the scs and the philippines in early to mid june the monsoon rain extends to the southwestern philippine sea after mid july the rainy season starts in the northeastern part of the wnp the onset anomaly however displays an in phase interannual variation across the entire wnp domain the standard deviation of the onset date increases eastward from 3 pentads in the scs to 5 pentads in the northeastern part of the domain the large onset variability in the wnp is mainly attributed to large year to year changes of the seasonal cycle

the pathfinder microrover an exciting scientific component of the pathfinder mission is the rover which will act as a mini field geologist by providing us with access to samples for chemical analyses and close up images of the martian surface performing active experiments to modify the surface and study the results and exploring the landing site area

active break cycles diagnosis of the intraseasonal variability of the asian summer monsoon in this study various diagnostics have been applied to daily observed outgoing longwave radiation olr and ecmwf reanalysis era products to provide a comprehensive description of the active break cycles associated with the asian summer monsoon and to address the differing behaviour of the two dominant time scales of intraseasonal variability 10 20 days and 30 60 days composite analysis of olr based on filtered daily all india rainfall air for the 40 day 30 60 days intraseasonal mode indicates that during active phases convection is significantly enhanced over the indian continent extending over the bay of bengal maritime continent and equatorial west pacific while convection is suppressed over the equatorial indian ocean and northwest tropical pacific resulting in a quadrapole structure over the asian monsoon domain in response to this heating pattern the large scale hadley lateral and the two east west transverse tropical circulations are enhanced there is also a significant impact on the extra tropical circulation through excitation and propagation of rossby waves in contrast the 15 day mode is more regional to the monsoon domain and has a prominent east west orientation in convection only the local hadley circulation over the monsoon region is modulated by this mode the evolution of these two modes as revealed by pop principal oscillation pattern analysis shows that the 40 day mode originates over the equatorial indian ocean once formed it has poleward propagation on either side of the equator and eastward propagation into the equatorial west pacific from the equatorial west pacific northward propagation over the west pacific and westward propagation into the indian longitudes are prominent the propagative features are complex and interactive and are responsible for the quadrapole structure in convection seen from the composites the interannual variability assessed from the pop coefficient time series indicates that the 40 day mode is strong during the onset phase of the monsoon in all the years but systematic propagation over the entire season depends crucially on the activity of the oceanic tcz tropical convergence zone the pop analysis of the 15 day mode indicates that this event originates over the equatorial west pacific associated with westward propagating rossby waves amplifies over the northwest tropical pacific and modulates both the continental and oceanic tczs over indian longitudes simultaneously this mode is pronounced during the established phase of the monsoon due to the complexity in the propagational features of both the intraseasonal modes it is concluded that understanding the subseasonal variability of one regional component of the asian summer monsoon asm requires understanding the entire asm system

quasi biweekly oscillation of the asian monsoon rainfall in late summer and autumn different types of structure and propagation this study contrasts two types of quasi biweekly oscillations qbwos over tropical asia in late summer and autumn from august to october using a tracking method to calculate the frequency of qbwo events over the asian monsoon region two types of qbwos in monsoon rainfall are revealed one originates from 110 to 140 e and propagates westward to southern china with a notable impact on the regional rainfall while the other initiates from 160 e to the dateline and does not affect southern china rainfall significantly analysis of the vertical structure of moisture flux shows that the moisture source for type 1 events is dominated by the zonal flux component and that for type 2 the meridional flux component the nature of the moisture flux determines whether the oscillation can propagate across 120 e and affect rainfall over southern china results also show that the strength of the south asian high and the western pacific subtropical high differently modulate the generation of the two types of qbwos specifically mutually stronger weaker highs favor the first second type of the oscillation a close relationship also exists between the qbwos and western pacific sea surface temperature sst anomalies suggesting that the sst anomalies can potentially trigger the qbwos

pacific east asian teleconnection how does enso affect east asian climate observational evidence is presented to show a teleconnection between the central pacific and east asia during the extreme phases of enso cycles this pacific east asian teleconnection is confined to the lower troposphere the key system that bridges the warm cold events in the eastern pacific and the weak strong east asian winter monsoons is an anomalous lower tropospheric anticyclone cyclone located in the western north pacific the western north pacific wind anomalies develop rapidly in late fall of the year when a strong warm or cold event matures the anomalies persist until the following spring or early summer causing anomalously wet dry conditions along the east asian polar front stretching from southern china northeastward to the east of japan kuroshio extension using atmospheric general circulation and intermediate models the authors show that the anomalous philippine sea anticyclone results from a rossby wave response to suppressed convective heating which is induced by both the in situ ocean surface cooling and the subsidence forced remotely by the central pacific warming the development of the anticyclone is nearly concurrent with the enhancement of the local sea surface cooling both the anticyclone and the cooling region propagate slowly eastward the development and persistence of the teleconnection is primarily attributed to a positive thermodynamic feedback between the anticyclone and the sea surface cooling in the presence of mean northeasterly trades the rapid establishment of the philippine sea wind and sst anomalies implies the occurrence of extratropical tropical interactions through cold surge induced exchanges of surface buoyancy flux the central pacific warming plays an essential role in the development of the western pacific cooling and the wind anomalies by setting up a favorable environment for the anticyclone sst interaction and midlatitude tropical interaction in the western north pacific

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

intraseasonal variability of the south china sea summer monsoon the objective of this study is to explore based on the national centers for environmental prediction national center for atmospheric research ncep ncar reanalysis data the intraseasonal variability of the south china sea scs summer monsoon sm in terms of its structure and propagation as well as interannual variations a possible mechanism that is responsible for the origin of the 10 20 day oscillation of the scs sm is also proposed the 30 60 day hereafter the 3 6 mode and 10 20 day hereafter the 1 2 mode oscillations are found to be the two intraseasonal modes that control the behavior of the scssm activities for most of the years both the 3 6 and 1 2 modes are distinct but may not always exist simultaneously in a particular year and their contributions to the overall variations differ among different years thus the interannual variability in the intraseasonal oscillation activity of the scs sm may be categorized as follows the 3 6 category in which the 3 6 mode is more significant in terms of the percentage of variance explained than the 1 2 mode the 1 2 category in which the 1 2 mode is dominant and the dual category in which both the 3 6 and 1 2 modes are pronounced composite analyses of the 3 6 category cases indicate that the 30 60 day oscillation of the scs sm exhibits a trough ridge seesaw in which the monsoon trough and subtropical ridge exist alternatively over the scs with anomalous cyclones anticyclones along with enhanced suppressed convection migrating northward from the equator to the midlatitudes the northward migrating 3 6 mode monsoon trough ridge in the lower troposphere is coupled with the eastward propagating 3 6 mode divergence convergence in the upper troposphere it is also found that for the years in the dual category the scs sm activities are basically controlled by the 3 6 mode but modified by the 1 2 mode composite results of the 1 2 mode category cases show that the 10 20 day oscillation is manifest as an anticyclone cyclone system over the western tropical pacific propagating northwestward into the scs a close coupling also exists between the upper level convergence divergence and the low level anticyclone cyclone it is found that the 1 2 mode of the scs sm mainly originates from the equatorial central pacific although a disturbance from the northeast of the scs also contributes to this mode the flow patterns from an inactive to an active period resemble those associated with a mixed rossby gravity wave observed in previous studies

early paleozoic radiolarian biozonation current knowledge of early paleozoic radiolarians permits the recognition of faunal assemblages and zones that constitute a biozonation this new zonation utilizes robust and relatively common easily recognized morphotypes it will facilitate rapid acquisition of previously unavailable age constraints for marine siliceous sedimentary successions in hitherto poorly understood early paleozoic orogenic collages

seasonal dependence of the mjo enso relationship abstract observations of the development of recent el nino events suggest a pivotal role for the madden julian oscillation mjo previous attempts to uncover a systematic relationship between mjo activity and the el nino southern oscillation enso however have yielded conflicting results in this study the mjo enso relationship is stratified by season and the focus is on mjo activity in the equatorial western pacific the results demonstrate that mjo activity in late boreal spring leads el nino in the subsequent autumn winter for the period 1979 2005 spring is the season when mjo activity is least asymmetric with respect to the equator and displays the most sensitivity to sst variations at the eastern edge of the warm pool enhanced mjo activity in the western pacific in spring is associated with an eastward expanded warm pool and low frequency westerly surface zonal wind anomalies these sustained westerly anomalies in the western pacific are hypothesized to project favorably onto a developing el n

seasonal modulation of tropical intraseasonal oscillations on tropical cyclone geneses in the western north pacific the seasonal modulationof tropicalintraseasonal oscillation tiso on tropicalcyclone tc geneses over the western north pacific ocean wnp is investigated in three periods of the wnp tc season may june mj july september jas and october december ond the modulation of the tiso tc geneses over the wnp is strong in mj while it appears weaker in jas and ond in mj tiso propagates northward via two routes the west route through the south china sea and the east route through the wnp monsoon trough region which are two clustering locations of tc geneses tiso can synchronously influence most tc geneses overthese two regions in jas however the modulation is out of phase betweenthe monsoontrough region and the east asian summer monsoon region as well as the wnp subtropical high region as a result of further northward propagation of tiso and scattered tc geneses the tiso tc genesis modulation in each individual region is comparable to that in mj although the modulation over the entire wnp in jas appears weaker in ond tiso has a stronger influence on tc geneses west than east of 1508e because tiso decays and its convection center located at the equator is out of the tc genesis region when propagating eastward into east of 1508e midlevel relative humidity is the primary contribution to the modulations of tiso on the genesis environment while vorticity could contribute to the modulation over the subtropics in jas

applied geochemistry geology and mineralogy of the northernmost carlin trend nevada investigations in the northernmost carlin trend were undertaken to advance understanding of the geochemical signatures and genesis of precious metal deposits in the trend two fundamental geologic relationships near the trend significantly affect regional geochemical distributions a remarkably intact lower paleozoic stratigraphic sequence of siliceous rocks in the upper plate of the middle paleozoic roberts mountains thrust and the widespread repetition of rocks high in the upper plate during late paleozoic thrusting that thickens the cover above mineralized rock in the lower plate a compilation of previously published chemical analyses of 440 stream sediment samples and 115 rocks from two 7 minute quadrangles as well as new chemical analyses of approximately 1 000 drill core samples in a 1 514 m 4 970 ft hole through the rodeo creek deposit were used to construct three dimensional element distribution models that highlight metal zonation in the mineralized systems the rodeo creek deposit comprises deep ag base metal au mineralized rock below the roberts mountains thrust and contains an unusually high ag au ratio greater than 30 stacked geochemical halos related to the deposit are confined to the lower plate of the roberts mountains thrust and include two horizons of hg cu and zn anomalies as much as 180 m above the deposit that mostly result from mercurian sphalerite extremely subtle indications of mineralization in the upper plate of the roberts mountains thrust above the deposit include arsenopyrite overgrowths on small pyrite crystals in 50 to 75 m wide clay carbonate veinlets that lack alteration halos arsenical rims on small disseminated crystals of recrystallized diagenetic pyrite and partial replacement of diagenetic pyrite by tennantite some of these minerals contain anomalously high au however these as au bearing rocks most likely represent another locus of largely untested mineralized rock rather than distal halos related to either the rodeo creek or the nearby dee and storm gold deposits application of micromineralogic techniques helped to identify mineral assemblages that are specific to mineralization and provided an empirical foundation for interpretations of geochemical halos in the carlin trend district scale geochemical patterns of several elements in stream sediments and surface rocks coincide with the northernmost carlin trend and can be used to explore for carlin type deposits concentrations of elevated as and sb in stream sediments as much as 54 ppm as have northwest elongate lobate patterns that clearly outline the trend across a width of approximately 4 km arsenic contents of exposed rocks as much as 90 ppm as strongly correlate with as contents of derivative stream sediments and rock contents of sb show a somewhat lesser but nonetheless strong and similar correspondence factor analysis of stream sediment data shows that those factor scores that are correlated with as sb au and pb also are high along the trend and suggest that mineralized rocks may be present although as was not detected by scanning electron microscope energy dispersive spectrometer sem eds studies in heavy mineral concentrates of high as stream sediments in the carlin trend x ray absorption near edge spectra xanes of selected light fractions of stream sediment samples indicate that al bearing phases such as gibbsite amorphous al oxyhydroxides or aluminosilicate clay minerals host most of the as v the best fit visually and in terms of the lowest residual was obtained by a model compound of as v sorbed to gibbsite thus most as in stream sediments derived from altered rock within the carlin trend apparently is contained in light fractions the geochemical character of young unconsolidated postmineral deposits that cover mineralized rocks on the carlin trend partly results from mineralized sources along the trend concentration of as in the miocene carlin formation shows an exceptionally well developed progressive increase to about 30 ppm as as altered rock surrounding the trend is approached mineralized and or altered rock fragments probably have been shed directly into the sedimentary basin of the carlin formation and migration of as now fixed as as v also may have occurred in the supergene environment after material was recycled out of the carlin formation and into present day gulleys

anticorrelated intensity change of the quasi biweekly and 30 50 day oscillations over the south china sea 1 over the south china sea the year to year variations in the intensity of the quasi biweekly qbw and 30 50 day oscillations during june july are anti correlated an explanation is offered for the out of phase relationship we found during strong qbw years the june july mean convection and easterly vertical shear are enhanced over the equatorial western central pacific with corresponding low level cyclonic meridional shear to the northwest these conditions concurring with the equatorial eastern pacific warming are favorable for emanation of moist rossby waves from the equatorial western pacific on the other hand the 30 50 day becomes active when the mean convection is enhanced over the eastern indian ocean and maritime continent where this mode stems from and develops which often corresponds to cold western io one of these two large scale settings often occurs in the absence of the other so that when one mode is strong during june july the other mode tends to be weak

impact of interannually varying background circulation on summertime wave patterns and tropical cyclone tracks in the western north pacific this study analyzed summertime wave patterns in the western north pacific by separating them into those during el nino en and la nina ln years for 1979 2015 the background flow revealed that in the en years the subtropical high was weaker and the east asian summer monsoon trough was deeper and extended farther southeastward the composite results indicated that in the en years tropical cyclone tc tracks were more solid and stably associated with wave pattern propagation routes because the circulation anomalies were significantly stronger however in the ln years when the wave patterns were weak under the shorter and less organized monsoon trough due to the enhanced subtropical high the tc tracks and cyclonic anomalies were irregular and sporadic further background flow analyses indicated that the en circulation favored the development of the monsoon trough and east west expansion and contraction of the subtropical ridge whereas the stronger subtropical ridge dominated most western north pacific areas in the ln years therefore the monsoon trough was weaker in the ln years and induced recurving tcs to take more scattered routes near taiwan and china s east coast therefore taiwan experienced more rainfall during recurving tc periods in the ln years than in the en years for the straight moving tcs passing through taiwan rainfall was concentrated over southern taiwan in the en years but more evenly distributed in the ln years thus background flow changes strongly affect wave patterns and tcs

the weakened intensity of the atmospheric quasi biweekly oscillation over the western north pacific during late summer around the late 1990s abstractthe interdecadal pacific oscillation ipo shifted to a negative phase around the late 1990s its impact on the atmospheric quasi biweekly oscillation qbwo intensity over the western north pacific wnp during late summer was investigated corresponding to the phase transition of the ipo la nina like sst anomalies and an enhanced walker circulation appeared in the tropical pacific which led to decreased precipitation over the equatorial central and eastern pacific the decreased precipitation induced a gill response with an anomalous anticyclone cyclone in the lower upper troposphere over the wnp this resulted in anomalous background westerly vertical shear over the tropical wnp furthermore the anomalous anticyclone induced anomalous horizontal divergence and descent motion in the planetary boundary layer which led to decreased background surface moisture over the tropical wnp these changes in background atmospheric conditions suppressed the development of qbwo perturbations over the

relationship between enso and northward propagating intraseasonal oscillation in the east asian summer monsoon system 1 observational studies are presented on the relationship between el nino southern oscillation enso and the northward propagating intraseasonal oscillation npiso in the east asian summer monsoon easm system the summer npiso activity shows a significant correlation with the preceding winter extreme phase of enso cycles a higher correlation appears during late summer which is consistent with frequent heavy rainfall events at that time as revealed in some previous case studies the westward expansion of broad anticyclonic circulation over the western north pacific and the smaller cyclonic circulation around korea and japan are found to be associated with the npiso activity enso affects the late summer npiso activity through an atmospheric bridge and wave propagation the springtime indian ocean sea surface temperature warming induced by enso through the walker circulation leads to the downward motion and suppressed convection over the philippine sea and this generates the forced rossby wave train forming the above south to north low level circulation anomalies

intraseasonal behavior of clouds temperature and motion in the tropics abstract the spectral character of tropical convection is investigated in an 11 yr record of outgoing longwave radiation from the advanced very high resolution radiometer to identify interaction with the tropical circulation along the equator in the eastern hemisphere the space time spectrum of convection possesses a broad peak at wave numbers 1 3 and eastward periods of 35 95 days significantly broader than the dynamical signal of the madden julian oscillation mjo this quasi discrete convective signal is associated with a large scale anomaly that propagates across and modulates time mean or climatological convection over the equatorial indian ocean and western pacific outside that region the convective signal is small even though under amplified conditions coherence can be found east of the date line and in the subtropics having a zonal scale of approximately wavenumber 2 anomalous convection propagates eastward at some 5 m s 1 and suppresses as well as reinforces climatological convection

visual and infrared observations of wind streaks on mars abstract estimation of surface properties and physical setting of three common martian wind streak types bright dark and splotch related provides constraints on models of the formation and variability of streaks bright streaks form independently of surface properties other than local topography this is consistent with their formation being due to deposition of atmospheric dust in the lee of topographic features although they are widespread on mars dark streaks are noted as variable only in regions near 30 s latitude and elevations between 3 and 7 km and are associated with dark surfaces that have relatively high thermal inertias splotch related streaks occur at elevations between 0 and 6 km and in regions of relatively high thermal inertia splotch related streaks occur near the boundaries of thermally defined regions such as the south polar cap and other areas of either low or high thermal inertia these thermal conditions are responsible for the production of surface winds which form and modify these streaks the source of sidements which form splotch related streaks varies from dunes to well indurated stratified deposits regional studies of the various types in syrtis major syria planum claritas fossae oxia palus mesogea and pettit craters and noachis confirm that the correlations found at the global level occur at regional scales

nature and distribution of surficial deposits in chryse planitia and vicinity mars color images of bright red dust deposits at the mutch memorial station were acquired at variable incidence angles during sol 611 subsolar longitude 70 northern spring season after removing effects due to atmospheric scattering and absorption the data were used to estimate the independent variables in the hapke 1986 photometric function in blue green and red coordinates the vector representing the space radiance factor of the landing site extracted from viking orbiter images acquired on sol 609 is separated by a euclidean distance of only 0 022 units and an angle of only 1 5 from the vector estimated from the station data for the orbiter lighting and viewing geometries this result implies that light reflected from dust exposures dominates the orbiter signal multiplicative and additive atmospheric terms cancel one another and surface roughness is a second order effect in the orbiter data dust radiance factors computed from station data are most like laboratory spectra for fine grained hawaiian palagonite and are indistinguishable from earth based spectra of classical bright areas color composites of orbiter images show that the dust is found immediately south of acidalia planitia and in association with topographic barriers such as craters and cliffs examination of viking infrared thermal mapper data shows that the dust deposits typically do not have distinctive thermal inertia signatures implying that the deposits are optically thick hundreds of micrometers but thinner than the diurnal thermal skin depth centimeters dark gray material with thermal inertia values 8 12 10 3 cal cm 2 s 1 2 k 1 indicative of sand grain sizes 0 5 1 5 mm dominates the acidalia planitia lowlands and parts of kasei vallis this material also occurs as dark streaks extending from craters in xanthe terra and oxia palus space radiance factors of dark gray material are similar to spectra of mafic rock mixed with a minor amount of palagonitelike material material that is darker than but just as red as the dust deposits occurs in lunae planum xanthe terra and oxia palus areas of intermediate elevation multiple phase angle orbiter images suggest that the dark red exposures are a mixture of bright red and dark gray materials with the dark red exposures being relatively rough at a subpixel scale as compared to exposures of the other two materials thus only two types of materials can be detected in the data covering the study area palagonitelike dust and mafic rock fragments thermal inertia values 4 8 10 3 cal cm 2 s 1 2 k 1 for the dark red material are consistent with the presence of fine to medium sand size particles 0 10 0 5 mm such material should be easily moved by winds the lack of aeolian features implies that the dark red deposits are not composed of loose material rather they are probably more eroded versions of blocky soil or duricrust cemented dust and rock fragments exposed at the station both bright red dust aeolian suspension load and dark gray materials saltation traction loads migrate over the dark red substrate the overall distribution of the surficial units is controlled by topography at a variety of length scales lower wind threshold friction velocities associated with higher atmospheric densities in lowlands keep dust from accumulating and duricrust from forming while higher threshold velocities in highlands lead to net accumulation of dust local topographic obstacles craters walls ridges perturb wind flow and lead to local accumulation or erosion at a variety of elevations in addition the bright red dust ubiquitously found between exposures of dark gray and dark red materials may accumulate as the wind velocity gradient decreases at the transition from smoother dark gray exposures to rougher dark red exposures the distribution of the materials must also be modulated by climatic variations induced by quasi periodic oscillations in obliquity eccentricity and spin axis direction constraining these surficial deposits to be 1 ma

surface geology from viking landers on mars a second look aside from reddish dust products of martian weathering are not abundantly obvious on viking lander images surface stones appear sound spalls and disintegration fragments are largely lacking pitting of stones is probably not due to differential weathering and reddish stone colors more likely result from adhered dust than from patination judging from wind scoured drifts deflated ground rippled bed forms lee side tails basal scours fretted rocks and ubiquitous dust wind is currently the most effective transportive and erosive agent the dogma that martian eolian material is almost exclusively of 10 100 size is challenged by granule ripples and the possibility that wind drifted deposits consist largely of sand sized particles fretting is more common than faceting on martian ventifacts crusts on martian surface fines are more akin to case hardened rinds than to true duricrust crusting a possibly continuing process may be the product of atmospheric breathing of the regolith pits on surfaces of many martian stones are probably vesicles modified by eolian erosion pits on nonvesicular rocks may be solely the product of wind blasting vesicular lava dense lava and breccias are the most likely rocks among surface stones around the landers the bedrock outcrops near vl 1 may be large boulders embedded in a breccia substrate pyroclastics seem a likely constituent of surface deposits

catastrophic flood sediments in chryse basin mars and quincy basin washington application of sandar facies model viking visible and thermal infrared observations and terrestrial catastrophic flood deposits provide clues to identify the outflow channel sediments that went into chryse basin on mars on earth sandar outwash plains formed by coalescence of many jokulhlaup floods are described in terms of three laterally adjacent facies proximal midfan and distal the missoula flood sediments deposited in quincy basin washington comprise a miniature analog of chryse basin the terminology and general characteristics of the sandar facies model are applied to quincy basin although the depositional environment and clast sizes are somewhat different higher energy flood larger clasts subaqueous rather than subaerial deposition for example the ephrata fan a deposit of boulders cobbles and pebbles forms the midfan facies analog a downfan sandy deposit reworked into a dune field comprises the distal facies analog in chryse basin the midfan is defined by a heterogeneous rocky 0 25 intermediate albedo 0 21 0 26 intermediate thermal inertia 260 460 j m 2 s 0 5 k 1 surface while the distal facies has a low albedo 0 14 0 16 and higher thermal inertia 340 700 j m 2 s 0 5 k 1 the chryse midfan unit has rocks and windblown dust exposed at the surface the sand of the distal facies in chryse acidalia is reworked by the wind as in quincy basin the viking 1 and mars pathfinder landing sites are located on the midfan unit observations that can be made at the mars pathfinder site might help in reevaluating whether or not viking 1 landed on outflow channel sediments

the influence of sea surface temperature on the tropical intraseasonal oscillation a numerical study abstract the development and movement of the tropical intraseasonal system tis exhibit remarkable annual variations it was hypothesized that spatial and temporal variation in sea surface temperature sst is one of the primary climatic factors that are responsible for the annual variation of tiss this paper examines possible influences of sst on the tis through numerical experiments with a 2 5 layer atmospheric model on an equatorial plane in which sst affects atmospheric heating via control of the horizontal distribution of moist static energy and the degree of convective instability the gradient of the antisymmetric with respect to the equator component of sst causes a southward propagation of the model tis toward northern australia in boreal winter and a northward propagation over the indian and western pacific oceans in boreal summer the phase speed of the meridional propagation increases with the magnitude of antisymmetric sst gradients the poleward propagation of the equatorial disturba

impact of the madden julian oscillation on summer rainfall in southeast china abstract the impact of the madden julian oscillation mjo on summer rainfall in southeast china is investigated using the real time multivariate mjo rmm index and the observational rainfall data a marked transition of rainfall patterns from being enhanced to being suppressed is found in southeast china east of 105 e and south of 35 n on intraseasonal time scales as the mjo convective center moves from the indian ocean to the western pacific ocean the maximum positive and negative anomalies of regional mean rainfall are in excess of 10 relative to the climatological regional mean such different rainfall regimes are associated with the corresponding changes in physical fields such as the western pacific subtropical high wpsh moisture and vertical motions when the mjo is mainly over the indian ocean the wpsh shifts farther westward and the moisture and upward motions in southeast china are increased in contrast when the mjo enters the western pacific the wpsh retreats eastward and the moi