high spatial resolution studies of epithermal neutron emission from the lunar poles constraints on hydrogen mobility 1 the data from the collimated sensors of the lend instrument are shown to be of exceptionally high quality counting uncertainties are about 0 3 relative and are shown to be the only significant source of random error thus conclusions based on small differences in count rates are valid by comparison with the topography of shoemaker crater the spatial resolution of the instrument is shown to be consistent with the design value of 5 km for the radius of the circle over which half the counts from the lunar surface would be determined the observed epithermal neutron suppression factor due to the hydrogen deposit in shoemaker crater of 0 25 0 04 cps is consistent with the collimated field of view rate of 1 7 cps estimated by mitrofanov et al 2010a the statistical significance of the neutron suppressed regions nsrs relative to the larger surrounding polar region is demonstrated and it is shown that they are not closely related to the permanently shadowed regions there is a significant increase in h content in the polar regions independent of the h content of the nsrs the non nsr h content increases directly with latitude and the rate of increase is virtually identical at both poles there is little or no increase with latitude outside the polar region various mechanisms to explain this steep increase in the non nsr polar h with latitude are investigated and it is suggested that thermal volatilization is responsible for the increase because it is minimized at the low surface temperatures close to the poles

anticipated electrical environment within permanently shadowed lunar craters 1 shadowed locations near the lunar poles are almost certainly electrically complex regions at these locations near the terminator the local solar wind flows nearly tangential to the surface and interacts with large scale topographic features such as mountains and deep large craters in this work we study the solar wind orographic effects from topographic obstructions along a rough lunar surface on the leeward side of large obstructions plasma voids are formed in the solar wind because of the absorption of plasma on the upstream surface of these obstacles solar wind plasma expands into such voids producing an ambipolar potential that diverts ion flow into the void region a surface potential is established on these leeward surfaces in order to balance the currents from the expansion limited electron and ion populations we find that there are regions near the leeward wall of the craters and leeward mountain faces where solar wind ions cannot access the surface leaving an electron rich plasma previously identified as an electron cloud in this case some new current is required to complete the closure for current balance at the surface and we propose herein that lofted negatively charged dust is one possible nonunique compensating current source given models for both ambipolar and surface plasma processes we consider the electrical environment around the large topographic features of the south pole including shoemaker crater and the highly varied terrain near nobile crater as derived from goldstone radar data we also apply our model to moving and stationary objects of differing compositions located on the surface and consider the impact of the deflected ion flow on possible hydrogen resources within the craters

models of the distribution and abundance of hydrogen at the lunar south pole 1 permanently shadowed locations at the lunar poles are potential sites for significant concentrations of cold trapped volatiles including water ice hydrogen enhancements are seen at the poles but the physical form abundance and distribution of this hydrogen remains controversial using a pixon based image reconstruction algorithm to effectively improve spatial resolution we derive maps of the lunar south polar water equivalent hydrogen concentration that are fully consistent with the orbital neutron measurements with abundances greater than 0 5 wt in some permanently shadowed locations this is much greater than the highest solar wind hydrogen abundance in returned lunar samples and may indicate ice between regolith grains if the hydrogen distribution is inhomogeneous within a permanently shadowed crater then even higher abundances are implied in shackleton crater for example the derived count rates are consistent with 10 of the crater floor area having 20 wt water equivalent hydrogen and the remainder at 0 25 wt

a geosat altimeter wind speed algorithm and a method for altimeter wind speed algorithm development a geosat altimeter wind speed algorithm is derived by cross calibrating geosat and seasat altimeter estimates of the normalized radar cross section 0 and modifying an existing seasat altimeter wind speed model function to obtain a model function appropriate for geosat observations it is argued that the 0 distribution measured by an altimeter is relatively stable over a sufficiently large geographical region and a long enough time period systematic differences between 0 estimates from two altimeters can therefore be identified based on comparisons of their 0 histograms any such systematic differences can then be corrected using independent 0 estimates when this method is applied to the geosat and seasat altimeters a systematic difference between the two 0 histograms is shown to be consistent with differences between seasat altimeter and nadir seasat scatterometer estimates of 0 deduced independently by a previous study this supports the conclusions that 1 the 0 distribution is stable and 2 the seasat altimeter estimates of 0 were miscalibrated after modifying the existing seasat altimeter wind speed algorithm to account for this apparent 0 error the resulting geosat estimates of wind speed agree with high quality buoy observations to within an rms difference of less than 2 m s

interannual and decadal variability of the subsurface thermal structure in the pacific ocean 1961 90 heat content anomalies are analyzed to understand subsurface variability on both aparticular focus on the evolving basinwide patterns and oceanic connections between the extratropics and tropics various analyses indicate two distinct modes one interannual and the other decadal that involve the tropics and the north pacific subtropical gyre respectively interannual variability is associated with el nino in the tropics with a prominent see saw pattern alternately on and off the equator and in the east and west respectively the interannual cycle features a coherent propagation of subsurface signals around the tropical pacific eastward along the equator but westward off the equator at 10 15 n decadal signals are dominant in the subtropics and midlatitudes but also have a tropical component that appears to be independent of interannual variations an oceanic connection can be seen between subsurface anomalies in the midlatitudes in the subtropics and tropics on decadal time scales subsurface thermal anomalies associated with midlatitude decadal variability can propagate through the subtropics into the tropics which may modulate the intensity of interannual variability in the tropics for example in the middle and late 1970s a significant warm temperature anomaly appeared to penetrate into the western and central tropics at depth warming the tropical upper ocean and depressing the thermocline during the development of el nino therefore an extratropically preconditioned subsurface state e g an enhanced positive heat content anomaly in the western and central tropical pacific would favor a warmer sea surface temperature anomaly in the eastern equatorial pacific potentially increasing the intensity of ocean atmosphere coupling these changes in the thermocline structure and possibly in the coupling strength can further alter the very character of tropical air sea interactions this may help to explain decadal variability of el nino evolution in the tropical pacific as observed in the 1980s our subsurface variability analysis presents observational evidence for the detailed space time structure of decadal oceanic links between the extratropics and the tropics

how different wind stress patterns affect the tropical subtropical circulations of the upper ocean abstract an oceanic gcm is used to investigate the response of the tropical and subtropical thermocline circulation and structure to different wind stress patterns although the subtropical winds do not affect the transport or the speed of the equatorial undercurrent significantly they do change the equatorial temperature field in the lower part of the equatorial thermocline significantly a weaker subtropical wind curl causes a cooling of the subsurface equatorial region and hence an intensification of the equatorial thermocline a weakening of the subtropical wind curl by a factor of 2 cools the equatorial lower thermocline water by 2 c

analyzing the ages of south polar craters on the moon implications for the sources and evolution of surface water ice abstract surface water ice in the permanently shadowed polar regions of the moon has a patchy surficial distribution and is not found within all available cold trapping areas to date it is not well understood when the ice was delivered which has important implications for the surficial characteristics of the ice as well as for possible delivery mechanisms here we present absolute model ages for 20 south polar craters that host surface water ice providing maximum estimates of the ages of surface ice contained within these craters we quantify the amount of available cold trapping surface area that is occupied by water ice in order to examine the relationship between the patchiness of ice within each crater and the age of each host crater the majority of surface ice is contained in old craters 3 1 gyr where the majority of cold trapping area on the pole exists the ice is these ancient craters is very patchy in surficial distribution occupying siegler et al 2016 if true polar wander did occur on the moon then the ages of ice bearing craters presented here set an upper limit for the age of post true polar wander hydrogen emplacement of 4 1 0 1 gyr

testing polar spots of water rich permafrost on the moon lend observations onboard lro 1 results are presented for the lend instrument onboard lro for the detection of local spots of suppression and excess of epithermal neutron emission at the lunar poles twelve local neutron suppression regions nsrs and neutron excess regions ners are detected it is shown using the data from the lola and diviner instruments that six nsrs have the empirical property less local irradiation and lower temperature fewer local neutrons these nsrs may be identified with spots of water ice rich permafrost on the moon it is shown that detected nsrs are include in both permanently shadowed and illuminated areas and they are not coincident with permanently shadowed regions psrs at the bottom of polar craters as has been commonly expected before lend presented neutron data with high spatial resolution

interdecadal sea surface temperature variability in the equatorial pacific ocean part ii the role of equatorial off equatorial wind stresses in a hybrid coupled model abstract many modeling studies have been carried out to investigate the role of oceanic rossby waves linking the off equatorial and equatorial pacific ocean although the equatorial ocean response to off equatorial wind stress forcing alone tends to be relatively small it is clear that off equatorial oceanic rossby waves affect equatorial pacific ocean variability on interannual through to interdecadal time scales in the present study a hybrid coupled model hcm of the equatorial pacific between 12 5 s and 12 5 n was developed and is used to estimate the magnitude of equatorial region variability arising from off equatorial poleward of 12 5 latitude wind stress forcing the hcm utilizes a reduced gravity ocean shallow water model and a statistical atmosphere derived from monthly output from a 100 yr australian bureau of meteorology research centre now the centre for australian weather and climate research coupled general circulation model integration the equatorial region wind stress forcing i

the seasat a satellite scatterometer the geophysical evaluation of remotely sensed wind vectors over the ocean on the seasat a satellite a microwave scatterometer was used to determine the vector wind over the world s oceans the technique is based on the sensitivity of microwave radar backscatter to the centimeter length ocean waves created by the action of the surface wind this paper describes the algorithm used to convert the scatterometer s measurements of ocean normalized radar cross section to the neutral stability vector wind at 19 5 m height and the comparison of these winds with high quality surface observations the wind vector algorithm used an empirical model function to describe the dependence of the ocean 0 on the 19 5 m neutral stability wind vector two model functions developed from a limited base of aircraft and satellite measurements were evaluated by using an independent set of in situ surface wind observations from the joint air sea interaction experiment jasin although these model functions were found to have some weaknesses the results of these comparisons produced better results than the seasat specifications of wind speed accuracy of 2 m s and wind direction accuracy of 20 over the 0 16 m s range of winds observed during jasin an improved model function was later developed by tuning to these jasin data so that the remaining biases between the observed surface winds and the scatterometer derived winds were minimized results are presented for this model function compared against other surface wind observations from the gulf of alaska seasat experiment and the seasat storms hurricane experiment

ventilation of the subtropical north pacific abstract the ventilation of the subtropical north pacific is studied using a simple analytical model the model is forced by winter mixed layer density and depth calculated from the levitus climatology and wind stress curl from the hellerman and rosenstein wind stress data the wind driven gyre in the north pacific is shallow no more than 1 4 km the gross feature of the subduction rate is very similar to the results by huang and qiu based on data analysis of the levitus climatology with a total ventilation rate of 31 3 sv sv 106 m3 s 1 including 20 8 sv due to the vertical pumping and 10 5 sv due to lateral induction the age of water within the ventilated thermocline is relatively young it is no more than 10 years old except near the southeast corner of the basin the young age indicates a fast communication between the atmosphere and the upper ocean on a timescale of less than 10 years the vertical mass partition is slightly different from the results based on analysing climatology by huang a

effects of orbital evolution on lunar ice stability 1 many regions near the lunar poles are currently cold enough that surface water ice would be stable against sublimation losses for billions of years however most of these environments are currently too cold to efficiently drive ice downward by thermal diffusion leaving impact burial as the primary means of protection from surface loss processes in this respect most of the present near surface thermal environments on the moon may actually be quite poor traps for water ice this was not always the case long term orbital changes have dramatically altered the lunar polar thermal environment we develop a simple model of the evolution of the lunar orbit and spin axis to examine the thermal environments available for volatile deposition and retention in the past our calculations show that some early lunar polar environments were in the right temperature regime to have collected subsurface ice if a supply were available however a high obliquity period which occurred when the moon was at about half its present distance from the earth would either have driven this ice out into space or deep into the lunar subsurface since that time as the lunar obliquity has slowly decreased to its present value environments have undergone their own thermal evolution and each of the current cold traps experienced a period when they were most efficient at thermally burying ice we examine the thermal history of a lunar polar crater to provide a framework for examining other processes effecting volatiles in the moon s near surface cold traps

the nature of lunar volatiles as revealed by mini rf observations of the lcross impact site 1 on 9 october 2009 the lunar crater observation and sensing satellite lcross impacted cabeus crater located near the south pole of the moon prior to that impact the mini rf instruments on isro s chandrayaan 1 and nasa s lunar reconnaissance orbiter lro obtained s band 12 6 cm synthetic aperture radar images of the impact site at 150 and 30 m resolution respectively these observations show that the floor of cabeus has a circular polarization ratio cpr comparable to or less than the average of nearby terrain in the southern lunar highlands furthermore 2 of the pixels in cabeus crater have cpr values greater than unity this observation is not consistent with the presence of thick deposits of nearly pure water ice within a few meters of the lunar surface but it does not rule out the presence of small 10 cm discrete pieces of ice mixed in with the regolith in addition mini rf on lro acquired a postimpact s band image of the region surrounding the lcross impact site providing important geologic context for the site registering the lro image to a near infrared nir image taken by the lcross shepherding spacecraft we find that the impactor landed in the ray of a fresh radar bright 1 km crater however the difference between preimpact and postimpact images is not above the speckle noise this implies that the size of the lcross impact crater is less than mini rf s resolution 30 m and or that the impact did not excavate more decimeter size blocks than were already present at the impact site

satellite altimeter measurements of surface wind recent analyses of wind speed measurements by the geosat altimeter showed that the radar cross section is affected by oceanographic factors particularly by the degree of sea development which are not directly accounted for in the geophysical model functions gmf in the present work two new gmfs which account for the effects of the actual degree of sea development are proposed along with the radar cross section these models use significant wave height information one particular version is recommended for applications in oceanographic and climate studies where wind speed or wind stress data have to be binned i e averaged over time and or space intervals the accuracy of this gmf overall bias of 0 1 m s and rms error of about 1 6 m s is higher than the accuracy of commonly employed gmfs while the wave age related trend is reduced to a geophysically insignificant level finally the wind speed histograms for the collocated data set are derived and compared with the ground truth data as well as with the histograms yielded by presently known gmfs it is also shown that the accuracy of altimeter measurements could be increased even further if some additional information on the wave field were available from independent sources e g the dominant wavelength from synthetic aperture radar images

an estimate of the geosat altimeter wind speed algorithm at high wind speeds existing wind speed algorithms for satellite altimeters have been developed from data in the range 0 to 20 m s at higher wind speeds the available algorithms diverge alarmingly by comparing geosat altimeter values of the radar cross section with model predictions of the surface winds during satellite overpasses of tropical cyclones a wind speed algorithm valid for wind speeds between 20 and 40 m s is developed there is however considerable scatter in these data an error analysis shows that this observed scatter is consistent with the accuracy to which the tropical cyclone wind fields can be inferred an approximately linear dependence of the radar cross section on wind speed is however clearly evident within these data at the lower limit of its applicability u10 20 m s these data are consistent with the previously derived algorithms at its upper limit u10 40 m s mean squared slope values inferred from the radar cross section are consistent with the theoretical upper limit

origin of upper ocean warming and el nino change on decadal scales in the tropical pacific ocean the cause of decadal scale variability in the tropical pacific ocean such as that marked by the 1976 77 shift in the el nino southern oscillation1 2 3 4 5 6 7 is poorly understood unravelling the mechanism of the recent decade long warming in the tropical upper ocean is a particularly important challenge given the link to el nino variability but establishing the hypothesized interannual decadal oceanic connections between middle latitudes and tropics has proved elusive8 here we present observational evidence that pacific upper ocean warming and decadal changes in the el nino southern oscillation after 1976 may originate from decadal mid latitude variability in the middle 1970s the north pacific ocean is observed to have undergone a clear phase transition a see saw subsurface temperature anomaly pattern that rotates clockwise around the subtropical gyre at middle latitudes a subsurface warm anomaly formed in the early 1970s from subducted surface waters and penetrated through the subtropics and into the tropics thus perturbing the tropical thermocline and driving the formation of a warm surface water anomaly that may have influenced el nino in the 1980s the identification of this teleconnection of extratropical thermal anomalies to the tropics through a subsurface ocean bridge may enable improved prediction of decadal scale climate variability

the migration of volatiles on the surfaces of mercury and the moon radar observations of mercury have provided the startling discovery of the probable existence of substantial deposits of ices in permanently shaded polar regions butler et al 1993 harmon et al 1994 this has renewed the old argument about the existence of such deposits in the polar regions of the moon it is most likely necessary for volatiles to be able to migrate to the polar regions of these bodies in order to build up such deposits this paper presents the results of the extension of a monte carlo simulation of the migration of molecules on the surface of mercury by butler et al 1993 the results of the simulations show that for typical conditions on mercury 5 15 of all h 2 o which is placed randomly on the surface migrates to stable permanently shaded polar regions for the moon the numbers are 20 50 the numbers for the migration of co 2 are 2 for mercury and 13 for the moon these percentages are similar to those previously calculated and support the idea of ice deposits in the polar regions of both mercury and the moon

evidence for water ice near the lunar poles improved versions of lunar prospector thermal and epithermal neutron data were studied to help discriminate between potential delivery and retention mechanisms for hydrogen on the moon improved spatial resolution at both poles shows that the largest concentrations of hydrogen overlay regions in permanent shade in the north these regions consist of a heavily cratered terrain containing many small less than 10 km diameter isolated craters these border circular areas of hydrogen abundance h that is only modestly enhanced above the average equatorial value but that falls within large flat bottomed and sunlit polar craters near the south pole h is enhanced within several 30 km scale craters that are in permanent shade but is only modestly enhanced within their sunlit neighbors we show that delivery by the solar wind cannot account for these observations because the diffusivity of hydrogen at the temperatures within both sunlit and permanently shaded craters near both poles is sufficiently low that a solar wind origin cannot explain their differences we conclude that a significant portion of the enhanced hydrogen near both poles is most likely in the form of water molecules

fluxes of fast and epithermal neutrons from lunar prospector evidence for water ice at the lunar poles maps of epithermal and fast neutron fluxes measured by lunar prospector were used to search for deposits enriched in hydrogen at both lunar poles depressions in epithermal fluxes were observed close to permanently shaded areas at both poles the peak depression at the north pole is 4 6 percent below the average epithermal flux intensity at lower latitudes and that at the south pole is 3 0 percent below the low latitude average no measurable depression in fast neutrons is seen at either pole these data are consistent with deposits of hydrogen in the form of water ice that are covered by as much as 40 centimeters of desiccated regolith within permanently shaded craters near both poles

a significant wave height dependent function for topex poseidon wind speed retrieval the ocean surface roughness affects the radar cross section measured by altimeters the wind speed is responsible for this roughness and most of present algorithms use the radar cross section rcs to infer it a few authors monaldo and dobson 1989 glazman and greysukh 1993 emphasized the influence of the sea maturity on satellite measurements they found a marginal improvement in wind speed retrieval by including significant wave height in their algorithm in this paper several previously established algorithms relating altimeter radar cross section to ocean surface wind speed are first analyzed the shapes of the rcs versus wind speed curves are shown to depend mainly on the minimization methods used to generate the model functions an empirical wind speed algorithm is then derived from the two altimeters alt and ssalt on board topex poseidon t p satellite using a quality controlled data set in which north atlantic operational surface wind and wave analyses are collocated with altimeter alt measurements unlike usual algorithms this new function depends on both the radar cross section and the significant wave height the improvement in the t p wind speed estimate seems significant at the 99 9 level the accuracy of the derived function is evaluated using an independent collocated ssalt and numerical weather prediction models data set here again the improvement is significant but at the 90 level because of the smaller amount of data available the t p wind speed estimates are furthermore compared to collocated estimates from national oceanic and atmospheric administration data buoys the new algorithm retrieves wind speed from geosat measurements with an accuracy compatible with usual algorithms

the relationship between wind vector and normalized radar cross section used to derive seasat a satellite scatterometer winds the dependence of ocean normalized radar cross section nrcs or 0 on the 19 5 m neutral stability wind vector for the seasat a satellite scatterometer sass is described for the sass wind vector algorithm this dependence is specified in the form nrcs u where is the radar incidence angle is the angle between wind direction and radar azimuth and u is the neutral stability wind speed in meters per second at a height of 19 5 m the development of models to express this relationship and to provide the basis for inversion of nrcs to sass winds is traced from its initial form based on aircraft scatterometer measurements through the seasat field validation experiments goasex storms and jasin to its final form comparison of the model nrcs versus surface wind speed with sass data from these experiments are made

ice in the polar regions of the moon recent laboratory measurements of the erosion of h2o ice are used to estimate the loss rates of possible trapped volatiles in the cold lunar polar regions we conclude that a significant accumulation of water ice is unlikely to occur

long term hydrographic changes at 52 and 66 w in the north atlantic subtropical gyre caribbean abstract in july september 1997 two hydrographic lines were done in the western n atlantic along longitudes of 52 and 66 w as part of the woce one time hydrographic survey of the oceans each of these two lines approximately repeated earlier ones done during the international geophysical year s igy and the mid 1980s because of this repeated sampling long term hydrographic changes in the water masses can be examined in this report we focus on temperature and salinity changes within the subtropical gyre mainly between latitudes of 20 and 35 n and compare our results to those presented by bryden et al 1996 who examined changes along a zonal line at 24 n most recently occupied in 1992 since this most recent 24 n section in 1992 substantial changes have occurred in the western part of the subtropical gyre at the depths of the labrador sea water lsw in particular we see clear evidence for colder fresher labrador sea water throughout the gyre on our two recent sections that was not yet present in 1992 at similar longitudes along 24 n at shallower depths inhabited by waters that are an admixture of mediterranean mw and antarctic intermediate waters aaiw our recent survey shows an increase in salinity which can only be attributed to changes in water masses on potential temperature or neutral density surfaces furthermore waters above the mw aaiw layer and into the deeper part of the main pycnocline have continued to become saltier and warmer throughout the 40 year period spanned by our sections these latter changes have been dominantly due to a vertical sinking of density surfaces as t s changes in density surfaces are small but depths of individual t s horizons have increased with time the net change since the igy shows a mean temperature increase between 800 and 2500 m depth at a rate of 0 57 c century with a corresponding steric sea level rise of 1 mm yr and a net downward heave with small values near the top and bottom and a maximum rate of 2 7 m yr at 1800 m depth changes in the deep caribbean indicate a warming since the igy due to temperature increases of the inflowing source waters in the subtropical gyre at 1800m depth but no significant change in the deep salinity

ice in the lunar polar regions revisited 1 the common wisdom that water ice may exist in lunar polar cold traps has become a significant factor in the selection of space research objectives the purpose of this paper is to address two topics that are missing from the discourse on lunar water the effect that the pristine cleanliness of the regolith has on water transport on the moon and the limits on water exposure implied by the extremely high adsorption potentials of the surfaces of soil grains water transport is characterized by chemisorption on soil grains and the mixing of wet grains into the regolith by meteoritic gardening ballistic lateral flow which is generally thought to be an efficient conduit for moving water to the poles is actually a secondary phenomenon that is facilitated by solar wind and micrometeor erosion but not by thermal desorption as is the case for the dominant lunar exospheric gases he and 40ar simulation results show that even under the most optimistic conditions less than 7 of the water accumulated in the regolith resides in the polar cold traps where water concentrations cannot be greater than 350 ppm more important when realistic transport parameters are used in the simulator the polar water concentration is reduced by almost 2 orders of magnitude in a word the concept of water ice at the lunar poles is insupportable

two dimensional distribution of volatiles in the lunar regolith from space weathering simulations 1 we present simulations of space weathering effects on ice deposits in regions of permanent shadow on the moon these monte carlo simulations follow the effects of space weathering processes on the distribution of the volatiles over time the model output constrains the coherence of volatile deposits with depth lateral separation and time the results suggest that ice sheets become broken and buried with time as impacts begin to puncture an initially coherent surficial ice sheet small areas with a deficit of ice compared to surrounding areas are formed first as time progresses holes become prevalent and the anomalous regions are local enhancements of ice concentration in a volume the 3 d distribution is also heterogeneous because the ice is buried to varying depths in different locations analysis of the coherence of ice on 10 cm scales predicts that putative ice sheets in anomalous radar craters are 1000 myr old for future in situ analysis of cold trap volatiles a horizontal range of 10 m is sufficient to acquire surface based measurements of heterogeneously distributed ice these results also support previous analyses that mercury s cold traps are young

intensity of satellite radar altimeter return power over continental ice a potential measurement of katabatic wind intensity au dessus de glace continentale antarctique des mesures d altimetrie radar par seasat commande automatique de gain ont ete effectuees les variations observees sont dues essentiellement a l intensite du vent catabatique

further development of an improved altimeter wind speed algorithm a previous altimeter wind speed retrieval algorithm was developed on the basis of wind speeds in the limited range from about 4 to 14 ms 1 in this paper we use a new approach which gives a wind speed model function applicable over the range 0 to 21 ms 1 the method is based on comparing 50 km along track averages of the altimeter normalized radar cross section measurements with neighboring off nadir scatterometer wind speed measurements the scatterometer winds are constructed from 100 km binned measurements of radar cross section and are located approximately 200 km from the satellite subtrack the new model function agrees very well with earlier versions up to wind speeds of 14 ms 1 but differs significantly at higher wind speeds we discuss the relevance of these results to the geosat altimeter launched in march 1985

recursive plasma wake formation on the moon and its effect on polar volatiles abstract solar wind plasma flows almost horizontally in near terminator regions of the moon one question is how does this plasma flow around topographic features like near terminator mountains and polar craters we present kinetic simulations of plasma inflow into a complicated polar crater having a second child crater within the parent crater i e a crater in a crater model we find that the effect on the inflowing ions of this second child feature is a function of its position downstream relative to the primary crater wall close to the wall where the solar wind is occulted there is little ion inflow and thus not a significant perturbation from the child obstruction however beyond about two crater wall heights downstream there is substantial ion flow and the child obstruction will create a second ambipolar wake region similar to that created by the first obstruction we also present a general analytical formalism that explains the most critical properties of the inflow perturbations finally we consider the effect of the ion inflow into polar craters with 1 water frost mixed within the top micron layers of the regolith we find that in order to maintain equilibrium a persistent frost most likely has to be maintained by a dynamic water source of 10 9 molecules m 2 s 1 in polar craters to offset solar wind ion inflow sputtering losses

monitoring of tropical cyclone structures in ten years of radarsat 2 sar images abstract the cross polarized synthetic aperture radar sar onboard the radarsat 2 satellite has the capability to simultaneously observe the tropical cyclone tc structure and ocean surface winds with high spatial resolution of 1 km and large swath images of 450 450 km we propose a methodology to extract tc centers radius of maximum winds intensities and the azimuthal wave number one asymmetric surface wind structures from 75 radarsat 2 cross polarized sar images over the period from 2008 to 2017 we present a quantitative investigation on both the symmetric mean flow and the asymmetries of azimuthal wave number one in the surface wind fields retrieved from these sar images the results demonstrate that the radius of maximum wind decreases as maximum wind increases which is consistent with the tc dynamic models for axisymmetric convective heating and that tcs are more asymmetric when they are weak and close to symmetric when they are strong

a simple model of the mass exchange between the subtropical and tropical ocean abstract a simple ventilated thermocline model is used to study the subtropical tropical mass exchange it is found that the water subducted in the western subtropical gyre recirculating window tends to recirculate within the subtropical gyre while the water subducted in the eastern part exchange window tends to penetrate equatorward the exchange window expands with an increased easterly wind or basin width on the southern boundary of the subtropical gyre but shrinks with an increased wind curl within the subtropical gyre furthermore the total exchange transport increases with the easterly wind or the width of the basin on the southern boundary of the subtropical gyre but it is independent of subtropical wind the ventilation mechanism is important in supporting the exchange transport for wind with realistic strength at the southern boundary the reduction of the exchange transport is about 15 30 of the ekman transport finally relative to the exchange transport in the interior of the ocean

permanent shadow in simple craters near the lunar poles 1 an analysis of simple craters in the lunar polar regions has produced new values for the minimum amount of permanent shadow in these areas 7500 km2 and 6500 km2 for the north and south pole respectively these values were obtained by conducting illumination simulations of realistically shaped simple craters 20 km in diameter to investigate the size and latitudinal extent of permanently shadowed regions near the lunar poles craters as far as 20 from the pole still contain significant amounts of permanent shadow larger simple craters have slightly more relative permanent shadow than smaller craters seasonal effects are independent of crater size and latitude with a crater having 15 more of its interior shadowed during a lunar day in winter than in summer

how dielectric breakdown may contribute to the global weathering of regolith on the moon abstract space weathering is an important process on airless bodies and it must be considered when interpreting data from planetary missions previous work has shown that solar energetic particles may cause dielectric breakdown in regolith within permanently shadowed regions near the poles of the moon here we predict that dielectric breakdown weathering could have melted and or vaporized 2 9 of gardened i e thoroughly mixed regolith at the equator and 5 11 near the poles if so then 3 10 of all gardened regolith on the moon may have experienced dielectric breakdown and this process must be considered when analyzing remote sensing data or soil samples returned by the luna and apollo missions

reanalysis of lunar prospector neutron spectrometer observations over the lunar poles 1 components of the neutron energy spectrum measured by instruments on the lunar prospector lp spacecraft have been optimistically interpreted as indicating massive deposits of water ice or other hydrogenic minerals in the polar regions of the moon an independent reanalysis of the theory of leakage neutrons shows that in addition to the observed depressions of the epithermal neutron flux the signature of polar hydrogen in the lunar regolith would have included a distinctive increase in the thermal neutron flux that apparently was not detected other simulations of lp neutron data show that the neutron signature of a mineralogical anomaly as simple as a localized excess of silicate would be about the same as that of hydrogen a deficit of cao would produce the lp result that is a decrease of epithermal neutrons with no noticeable change in the thermal neutron flux other more complicated mineral variants could yield similar effects what is clear is that the existence of polar water ice or hydride deposits has not been proven by analyses of lunar prospector data

adjustment of the ventilated thermocline the time dependence of the ventilated thermocline is examined via analytical and numerical means the original henderschott model is modified such that the outcrops all occur on the same geopotential surface rather than at staggered geopotential surfaces this model has the advantage that the ocean interior can be ventilated directly by the sverdrup flow rather than by western boundary processes the propagation of disturbances governed by linearized forms of the three layer or four layer modified henderschott model nonlinear solutions of the full modified henderschott model and numerical solutions of the planetary geostrophic equations are considered low frequency disturbances are predicted by the linear models to move on characteristics jointly set by advection and wave dynamics it is shown that perturbations due to wind stress anomalies project strongly onto the first mode and propagate westward similarly to the classical first baroclinic rossby mode they do not experience much interaction with the mean flow the so called non doppler effect on the other hand perturbations generated by buoyancy anomalies have strong projections onto the second or third modes and propagate along pathways very close to the mean circulation their speed is somewhat slower than the current speed however these properties appear in the linearized and simplified nonlinear models and their occurrence in planetary geostrophic results argues the relevance of the henderschott model also these properties are consistent with results from other studies

climate variability induced by anomalous buoyancy forcing in a multilayer model of the ventilated thermocline climate variability induced by surface cooling in a four moving layer model of the ventilated thermocline is studied the perturbations propagate within the characteristic cones defined by streamlines in individual layers where the potential vorticity anomaly is created each time the characteristic cones cross a new outcrop line the number of characteristic cones doubles thus climate variability in a multilayer model can have very complicated structure in the horizontal plane with anomalies of alternating sign the vertical structure of such perturbations defines a class of dynamical thermocline modes

on using significant wave height and radar cross section to improve radar altimeter measurements of wind speed wind blowing across the ocean surface generates small centimeter scale roughness the radar cross section rcs measured by spaceborne nadir looking altimeters operating at about 13 5 ghz is responsive to this roughness present altimeter algorithms use rcs to infer wind speed we compare geosat altimeter estimates of wind speed and nearly coincident estimates from noaa data buoys to determine whether altimeter algorithms can be improved by using more of the information available from altimetry we find that a marginal improvement in wind speed retrievals can be obtained by including additional rcs information and significant wave height in the retrieval algorithm perhaps most important results also suggest that wind wave growth is suppressed in the presence of preexisting ocean swell

decadal variability of temperature at a depth of 400 meters in the north pacific ocean the gyre scale structure and evolution of decadal ocean thermocline variability in the north pacific is described by analyzing historical temperature data at a depth of 400 meters decadal thermocline anomalies are characterized by a distinct see saw pattern in the midlatitudes and subtropics that appears to circulate coherently in the north pacific basin with a period on the order of 20 years there are coherent spatial and temporal relationships between temperature anomalies around the subtropical gyre with phase differences at depth and at the sea surface suggesting that thermocline variability evolves independently of local sst anomalies in the subtropics subsurface anomalies can be seen to propagate all the way across the basin and thereby lead sst anomalies providing a possible phase transition mechanism for sst the basinwide anomaly pathways suggest a clockwise advection of subsurface temperature anomalies around the subtropical gyre an active role played by the mean geostrophic flow in decadal variability

upper ocean thermal variations in the north pacific during 1970 1991 abstract a newly available extensive compilation of upper ocean temperature profiles was used to study the vertical structure of thermal anomalies between the surface and 400 m depth in the north pacific during 1970 1991 a prominent decade long perturbation in climate occurred during this time period surface waters cooled by 1 c in the central and western north pacific and warmed by about the same amount along the west coast of north america from late 1976 to 1988 comparison with data from coads suggests that the relatively sparse sampling of the subsurface data is adequate for describing the climate anomaly the vertical structure of seasonal thermal anomalies in the central north pacific shows a series of cold pulses beginning in the fall of 1976 and continuing until late 1988 that appear to originate at the surface and descend with time into the main thermocline to at least 400 m depth individual cold events descend rapidly 100 m yr 1 superimposed upon a slower cooling 15 m yr 1 the inter

subduction of decadal north pacific temperature anomalies observations and dynamics abstract observations of oceanic temperature in the upper 400 m reveal decadal signals that propagate in the thermocline along lines of constant potential vorticity from the ventilation region in the central north pacific to approximately 18 n in the western pacific the propagation path and speed are well described by the geostrophic mean circulation and by a model of the ventilated thermocline the approximate southward speed of the thermal signal of 7 mm s 1 yields a transit time of approximately eight years the thermal anomalies appear to be forced by perturbations of the mixed layer heat budget in the subduction region of the central north pacific east of the date line a warm pulse was generated in the central north pacific by a series of mild winters from 1973 to 1976 and reached 18 n around 1982 after 1978 a succession of colder winters initiated a cold anomaly in the central north pacific that propagated along a similar path and with a similar speed as the warm anomaly then arrived in the west

structure and cycle of decadal variability of upper ocean temperature in the north pacific abstract yearly upper ocean in situ temperature anomaly data for the period 1961 90 are analyzed to reveal spatial structure and evolution of decadal variability in the north pacific ocean an eof analysis has been performed on individual temperature anomaly fields at upper ocean standard levels as well as simultaneously on the entire upper ocean data to depict the combined three dimensional structure in a coherent manner time evolution of anomaly fields is depicted by using a regression analysis the analyses detect the principal basin scale structure of decadal warm period dwp and decadal cold period dcp there is a well defined subsurface thermal anomaly pattern characterized by a prominent seesaw structure with opposite anomaly polarity between the midlatitude north pacific and the subtropical regions during a dwp a positive temperature anomaly is found in the central midlatitude upper ocean with the maximum at about 100 m depth this is accompanied by a corresponding negative anomaly in the

topography of the lunar poles from radar interferometry a survey of cold trap locations detailed topographic maps of the lunar poles have been obtained by earth based radar interferometry with the 3 5 centimeter wavelength goldstone solar system radar the interferometer provided maps 300 kilometers by 1000 kilometers of both polar regions at 150 meter spatial resolution and 50 meter height resolution using ray tracing these digital elevation models were used to locate regions that are in permanent shadow from solar illumination and may harbor ice deposits estimates of the total extent of shadowed areas poleward of 87 5 degrees latitude are 1030 and 2550 square kilometers for the north and south poles respectively

near surface temperatures on mercury and the moon and the stability of polar ice deposits abstract in order to assess the thermal stability of polar ice deposits we present model calculated temperatures of flat surfaces and surfaces within bowl shaped and flat floored polar impact craters on mercury and the moon our model includes appropriate insolation cycles realistic crater shapes multiple scattering of sunlight and infrared radiation and depth and temperature dependent regolith thermophysical properties unshaded water ice deposits on the surface of either body are rapidly lost to thermal sublimation a subsurface water ice deposit is stable within 2 latitude of the moon s poles meter thick water ice deposits require billions of years to sublime if located in the permanently shaded portions of flat floored craters within 10 latitude of the poles of mercury and 13 latitude of the poles of the moon results for craters associated with radar features on mercury are consistent with the presence of stable water ice deposits if a thin regolith layer thermally insulates deposits at lower latitudes and within smaller craters a regolith cover would also reduce losses from diffusion ion sputtering impact vaporization and h ly and is implied independently by the radar observations permanently shaded areas near the moon s poles are generally colder than those near mercury s poles but the moon s obliquity history its orbit through earth s magnetospheric tail and its radar opaque regolith may limit the volume and radar detectability of ice deposits there

a geologic model for lunar ice deposits at mining scales abstract water ice has been detected at the lunar poles but existing and near future orbital datasets do not have the capabilities to determine its horizontal and vertical distribution at meter to hundred meter scales relevant for mining operations additionally there has not yet been a coherent geologic model put forward for how ice deposits have formed and evolved that can be used to assist in planning prospecting campaigns or developing relevant hardware here we propose a system model for understanding these deposits at scales of meters to hectares the model considers sources of water ice capture at and below the surface and retention it focuses heavily on impact gardening as a modifying process that drives changes in how ice is distributed 3 dimensional stochastic impact simulations are then used to test the system model and explore how ice deposits might evolve over an area the size of a potential mining outpost the simulation results showed ice concentrations should eventually become fairly homogeneous at meter to hectare scales due to impact gardening and high concentrations are distributed randomly rather than clustered in earth like ore bodies we found the best ice deposits for extracting likely exist 10s of cm deep or more even in locations where ice is currently stable at the very surface terrestrial mining software was then used to create block models and grade tonnage curves that can inform future in situ resource utilization demonstration missions and future mining operations planning

the sea state correction for geos 3 and seasat satellite altimeter data troughs of the ocean surface reflect more electromagnetic radiation to a satellite altimeter than crests causing an apparent lengthening of the altimeter path this effect called the em bias has been estimated to be 2 10 of significant wave height swh by various authors from geos 3 and aircraft experiments or theoretical analyses for the case of the seasat altimeter born et al 1982 at jet propulsion laboratory jpl made an empirical estimate that gave the total correction to the altimeter path length as 7 of the swh a large value was expected for seasat because an instrumental effect in addition to the em bias is known to exist waveform analyses performed at nasa wallops flight center hayne and hancock 1982 give a correction for the instrument effect but according to the authors their results cannot be compared with results obtained elsewhere for several reasons including the large uncertainty 30 of the jpl result in this paper we resolve the situation for both geos and seasat altimeters by reinterpreting the results of hayne and hancock and making empirical studies using very large data sets to estimate the correction required for the effect of sea state empirical estimates of the correction were made by finding a value that minimized in the sense of least squares the differences of many about 300 repeated pairs of altimetric profiles for each satellite the total correction obtained is 1 9 of significant wave height for geos 3 and 6 4 for seasat the latter result consistent with the analysis done at jpl of a smaller data set and our interpretation of the hayne and hancock waveform analysis

structure and evolution of interannual variability of the tropical pacific upper ocean temperature n n yearly in situ temperature anomaly data for the period 1961 1990 are analyzed to reveal the dominant structure and evolution of interannual variability of the tropical pacific upper ocean we use multivariate empirical orthogonal function eof analyses to detect the principal three dimensional structure related to el nino there are well defined subsurface thermal patterns characterized by a prominent sea saw structure with opposite anomaly polarity in the equatorial and off equatorial tropical north pacific regions during an el nino year a positive temperature anomaly is found in the e astern and central tropical upper ocean this is accompanied by a corresponding negative anomaly at subsurface depths in the west with a maximum at 100 150 m off the equator unlike sea surface temperature whose variations are confined largely to the east with one dominant polarity temperature variations at 50 200 m depths have a dipole pattern with out of phase oscillations in the central equatorial pacific and in the western tropical north pacific a reverse pattern of these anomalies is observed during a la nina year evolution between el nino and la nina involves a significant zonal transfer of anomaly phase across the equatorial basin as well as across the off equatorial tropical north pacific showing consistent and coherent variations from west to east from subsurface to sea surface and from on the equator to off the equator this phase propagation is more evident at subsurface depths than that at the sea surface suggesting a continual movement of anomaly pattern in succession eastward along the equator and westward off the equator of the tropical north pacific with spatial inhomogeneities of zonal propagation in longitude our analyses present evidence of the manner in which temperature anomalies evolve at subsurface ocean depths in the tropical pacific thus providing an observational basis for evaluating theoretical studies and model simulations the dynamical implication of these results is also discussed

subsurface migration of h2o at lunar cold traps 1 permanently shaded areas near the poles of the moon and mercury may harbor water ice we develop a physical model for migration of water molecules in the regolith and discover two pathways that can lead to accumulation of h2o in the subsurface a small fraction of water molecules delivered either continuously or abruptly to permanently cold areas diffuses into the regolith and can remain there longer than on the surface higher temperatures lead to deeper burial at constant temperature this diffusive migration produces less than one molecular layer of volatile h2o on grains because it is driven by differences in surface concentrations the water is therefore expected to be in adsorbed form and the amount stored in this fashion could be at most a few hundred ppm of h2o a second pathway is pumping by diurnal temperature oscillations from a transient ice cover that may have formed during a large comet impact it can lead to high ground ice densities but the ground ice layer lasts not long beyond the disappearance of the ice cover both types of subsurface charging mechanism work best for temperatures typical of permanently shaded areas with sunlit surfaces in their field of view

burial rate of mercury s polar volatile deposits 1 delay doppler images of mercury s polar regions showing enhanced radar backscatter have been interpreted as evidence for water ice in the polar craters and are consistent with pure water ice covered by about 20 cm of regolith in this paper we assume that the volatile at the hermean poles is water ice and that it was initially deposited at one time in a clean layer we constrain the time of such an impact by determining the rate of regolith emplacement the rate of burial of ice deposits in polar craters on mercury is estimated to be 0 43 cm myr if the ice deposits in hermean polar craters are both clean and buried by 20 cm of regolith they must be relatively recently emplaced 50 myr ago the predicted h concentration in the uppermost meter of regolith is calculated as a function of both time since emplacement of the ice and initial thickness of the ice layer the combination of neutron data and radar data can provide additional insight into the size and age of ice deposits at mercury

interdecadal variability of the pacific ocean model response to observed heat flux and wind stress anomalies variability of the pacific ocean is examined in numerical simulations with an ocean general circulation model forced by observed anomalies of surface heat flux wind stress and turbulent kinetic energy tke over the period 1970 88 the model captures the 1976 77 winter time climate shift in sea surface temperature as well as its monthly seasonal and longer term variability as evidenced in regional time series and empirical orthogonal function analyses examination of the surface mixed layer heat budget reveals that the 1976 77 shift was caused by a unique concurrance of sustained heat flux input anomalies and very strong horizontal advection anomalies during a multi month period preceding the shift in both the central pacific region where cooling occurred and the california coastal region where warming occurred in the central pacific the warm conditions preceding and the cold conditions following the shift tend to be maintained by anomalous vertical mixing due to increases in the atmospheric momentum flux tke input into the mixed layer which deepens in the model after the shift from the early 1970s to the late 1970s and 1980s since the ocean model does not contain feedback to the atmosphere and it succeeds in capturing the major features of the 1976 77 shift it appears that the midlatitude part of the shift was driven by the atmosphere although effects of midlatitude ocean atmosphere feedback are still possible the surface mixed layer heat budget also reveals that in the central pacific the effects of heat flux input and vertical mixing anomalies are comparable in amplitude while horizontal advection anomalies are roughly half that size in the california coastal region in contrast where wind variability is much weaker than in the central pacific horizontal advection and vertical mixing effects on the mixed layer heat budget are only one quarter the size of typical heat flux input anomalies

a statistical comparison of wind speed wave height and wave period derived from satellite altimeters and ocean buoys in the gulf of mexico region the capability of spaceborne altimeters to provide precise measurement of significant wave height and wind speed has been demonstrated repeatedly it is shown in this paper that in addition to the significant wave height and wind speed the wave period can be calculated from the semiempirical functions established from earlier wave research the calculated characteristic wave period using the altimeter derived wind speed and wave height are found to be in excellent agreement with the peak wave period and average wave period from the ocean buoy measurements in the gulf of mexico also with the long time series of collocated data set it is possible to compare altimeter output of wind and wave parameters with ocean buoy measurements taking into consideration the spatial lags between the buoy locations and the altimeter footprints and the temporal lags between the two sensor systems it is found that when the spatial lags are less than 10 km the rms difference of the significant wave height is approximately 0 1 m which is the digitization resolution of the output from both altimeter and ocean buoy for the wind speed the rms difference approaches 1 2 m s in the gulf of mexico using the empirical algorithms the wind speed agreement is significantly improved to 0 8 m s when the tilting effect on the altimeter cross section is accounted for in contrast to the spatial lags temporal lags of up to 1 hour do not appear to produce significant difference in the statistics of comparison based on this study

lack of exposed ice inside lunar south pole shackleton crater the inside of shackleton crater at the lunar south pole is permanently shadowed it has been inferred to hold water ice deposits the terrain camera tc a 10 meter resolution stereo camera onboard the selenological and engineering explorer selene spacecraft succeeded in imaging the inside of the crater which was faintly lit by sunlight scattered from the upper inner wall near the rim the estimated temperature of the crater floor based on the crater shape model derived from the tc data is less than 90 kelvin cold enough to hold water ice however at the tc s spatial resolution the derived albedo indicates that exposed relatively pure water ice deposits are not on the crater floor water ice may be disseminated and mixed with soil over a small percentage of the area or may not exist at all

space weathering effects on lunar cold trap deposits 1 both steady and episodic sources have been proposed as sources of hydrogen observed by lunar prospector in association with the regions of permanent shadow at the poles of the moon either source could supply significant quantities of water to the poles however space weathering processes affect the retention of water in the cold traps we investigate those effects by simulating the evolution of a column of regolith in the region of permanent shadow over time we determine the hydrogen concentration as a function of depth using a monte carlo model of discrete impacts and of delivery from the solar wind we treat the delivery sublimation sputtering and very small scale impacts as continual processes comparing the amount of water delivered to the poles to the amount remaining after space weathering we find a retention efficiency of 5 6 the retention efficiency of the polar cold traps is adequate for preserving volatile deposits over long periods of time the average hydrogen concentration in the regolith column is 4100 ppm in the top meter after 1 gyr this is a saturation level in the regolith increasing the amount of time deepens the enriched layer but does not lead to increased concentrations in 1 gyr about 1 6 m of the regolith is gardened therefore the top meter which is probed by the neutron spectroscopy technique has reached steady state in the simulations the 4100 ppm saturation level is about half of the amount of hydrogen inferred from the lunar prospector neutron data

an empirical determination of the effects of sea state bias on seasat altimetry a simple linear empirical model has been developed to allow the user of seasat altimetry data to correct the altitude measurements for sea state bias effects this bias is the result of two separate effects one relating to instrumental effects and the other relating to a bias in the electromagnetic mean sea level relative to the geometric mean sea level the electromagnetic bias is caused by the fact that the troughs of the ocean waves reflect the altimeter signal more strongly than the crests thus causing the altimeter determined mean sea level to shift toward the wave troughs an additional but independent instrument related bias is introduced because height corrections applied in the ground processor are not sufficient to compensate for simplifying assumptions made for the processor aboard seasat this altitude bias also is predominately wave height dependent and directed toward the wave trough the sum of these two effects is referred to as sea state bias after applying appropriate corrections to the altimetry data an empirical model for the sea state bias is obtained by differencing significant wave height and height measurements from coincident ground tracks ignoring small temporal variations in surface topography the height differences on a given track should be zero consequently any residual height difference is attributed to sea state bias the height differences are minimized by solving for the coefficient of a linear relationship between height differences and wave height differences that minimize the height differences it is concluded that for the altimeter data released by the jet propulsion laboratory 7 of the value of significant wave height should be subtracted from the seasat height measurements to correct for sea state bias this correction reduced biases in the seasat data by more than 50 in the 36 cases examined here

late winter generation of spiciness on subducted isopycnals the origins of density compensating anomalies of temperature and salinity spice are investigated using a model forced with the most realistic surface products available over the 40 years 1958 97 in this hindcast the largest interannual spiciness anomalies are found in the pacific ocean near the isopycnal s 0 5 25 5 where deviations as great as 1 28c and 0 6 psu are generated equatorward of winter outcropping in the eastern subtropics in both hemispheres these source regions are characterized by very unstable salinity gradients and low mean density stratification in winter two related signatures of winter mixing in the southeast pacific sep are density that is well mixed deeper than either temperature or salinity and subsurface density ratios that approach 1 all ocean basins in the model are shown to have regions with these characteristics and signatures however the resultant spiciness signals are focused on different isopycnals ranging from s 0 5 25 0 in the northeast pacific to s 0 5 26 5 in the south indian ocean a detailed examination of the sep finds that large positive anomalies are generated by diapycnal mixing across subducted isopycnals e g s 0 5 25 5 whereas negative anomalies are the result of a steady isopycnal advection moderated by vertical advection and heave there is considerable interannual variability in the strength of anomalies and in the density on which they occur historical observations are consistent with the model results but are insufficient to verify all aspects of the hindcast including the processes of anomaly generation in the sep it was not possible to relate isopycnal anomaly genesis to local surface forcing of any kind a complex scenario involving basinwide circulation of both the ocean and atmosphere especially of surface water through the subtropical evaporation zones is put forward to explain the decadal time scale evident in sep salinity anomalies on s 0 5 25 5 pacific anomalies generated on s 0 5 25 5 can be traced along mean geostrophic streamlines to the western boundary where decadal salinity variations at 78s are about 2 times as large order 60 1 psu as at 128n although there may be more variance on shallower isopycnals in the north at least portions of the s 0 5 25 5 signals appear to continue along the boundary to a convergence at the equator suggesting that the most robust sources of pacific spiciness variance coincide with equatorial exchange pathways

exospheric transport restrictions on water ice in lunar polar traps there is little doubt that at least 1017 g of water has accreted on the moon as a result of the reduction of ferric iron at the regolith surface by solar wind protons the vaporization of chondrites and perhaps comet impacts lacking an efficient escape mechanism most of this water or its progeny is probably on the moon now if the water were to have migrated to permanently shaded cold traps near the lunar poles ice deposits with densities greater than 1000 g cm 2 would cover the traps providing accessible resources however exospheric transport considerations suggest that the actual amount of water ice in the cold traps is probably too small to be of practical interest the alternative is global assimilation of most of the water into the regolith a process that must account for about 30 micromoles of water per gram of soil

climate variability inferred from a continuously stratified model of the ideal fluid thermocline climate variability in the subtropical gyre interior induced by anomalous surface thermal forcing ekman pumping mixed layer depth variability and anomalous subpolar water formation is examined using a continuously stratified model of the ideal fluid thermocline cooling heating induces a negative positive potential vorticity perturbation in the ventilated thermocline and the associated density perturbations propagate downstream in the form of second and higher baroclinic modes the second baroclinic mode resembles the traditional second baroclinic mode because it has a thermal structure with cooling warming in the upper thermocline and warming cooling in the lower thermocline anomalous ekman pumping can also induce density perturbations that propagate westward in the form of the first baroclinic mode in addition if the outcrop lines are nonzonal there are density perturbations that propagate downstream in the form of the second or third baroclinic modes perturbations in the sea surface elevation are mostly confined to the region of anomalous forcing on the other hand when the low potential vorticity anomaly in the subpolar mode water spreads into the subtropical basin both the unventilated and ventilated thermocline move downward consequently temperature at a given depth seems to increase

evidence for stronger el nino southern oscillation enso events in a mid holocene massive coral we present a 47 year long record of sea surface temperature sst derived from sr ca and u ca analysis of a massive porites coral which grew at 4150 calendar years before present b p in vanuatu southwest tropical pacific ocean mean sst is similar in both the modern instrumental record and paleorecord and both exhibit el nino southern oscillation enso frequency sst oscillations however several strong decadal frequency cooling events and a marked modulation of the seasonal sst cycle with power at both enso and decadal frequencies are observed in the paleorecord which are unprecedented in the modern record

the lunar reconnaissance orbiter mission six years of science and exploration at the moon abstract since entering lunar orbit on june 23 2009 the lunar reconnaissance orbiter lro has made comprehensive measurements of the moon and its environment the seven lro instruments use a variety of primarily remote sensing techniques to obtain a unique set of observations these measurements provide new information regarding the physical properties of the lunar surface the lunar environment and the location of volatiles and other resources scientific interpretation of these observations improves our understanding of the geologic history of the moon its current state and what its history can tell us about the evolution of the solar system scientific results from lro observations overturned existing paradigms and deepened our appreciation of the complex nature of our nearest neighbor this paper summarizes the capabilities measurements and some of the science and exploration results of the first six years of the lro mission

polar hydrogen deposits on the moon neutron and gamma ray data measured using the lunar prospector spectrometers were analyzed to define the enhanced hydrogen deposits near both poles of the moon combining the new low altitude neutron data 30 15 km with previous high altitude 100 20 km neutron data and the results of several recent radar investigations sharply constrains the characteristics of each of the polar deposits the deposits at the north appear to be in the form of many small pockets or of generally distributed hydrogen that average to a 100 ppm weight fraction enhancement over that which exists in regolith at more equatorial latitudes those deposits in the permanently shaded craters near the south pole are consistent with a thick ferroan anorthosite regolith containing an enhancement of 1670 890 ppm hydrogen which if in the form of water ice amounts to 1 5 0 8 weight fraction of h sub 2 o neutron data alone cannot discriminate between hydrogen implanted in lunar soil from the solar wind hydrated minerals or h sub 2 o these craters appear to be surrounded by regolith that either contains small pockets of enhanced hydrogen or is soil that is uniformly impregnated with hydrogen enhanced on average by about 100 ppm above that contained in soils at more equatorial latitudes c more 2000 american geophysical union less

evolution of interdecadal variability in sea level pressure sea surface temperature and upper ocean temperature over the pacific ocean abstract interdecadal variability in sea level pressure slp and sea surface temperature sst anomalies in the pacific ocean was quasiperiodic from 1900 91 the coherent variability of this phenomenon is investigated using gridded observational data from the turn of the century sst and slp and of upper ocean heat content hs from the recent two and a half decades the nominal cycle in atmosphere ocean variables is roughly two decades long but growth and decay can happen on a shorter timescale e g half a cycle or so the authors divide the full cycle into four phases an onset phase during which a weak slp anomaly pattern off japan takes approximately 2 4 yr to expand eastward leads to large slp anomalies in the region of the aleutian low a quasi stationary growth phase with the midlatitude slp anomaly pattern in the eastern ocean intensifies over a 2 4 yr period the persistent slp anomalies evolve in concert with large sst and hs anomalies of the same polarity located to the south sout

validation of geosat altimeter derived wind speeds and significant wave heights using buoy data this paper presents a comparison of geosat radar altimeter derived wind speeds and significant wave heights with those measured by buoys in the national data buoy center ndbc network measurements from a subset of 43 buoys moored in coastal regions and deep ocean including the north pacific north atlantic and gulf of mexico were examined data from other buoys within the ndbc network were not included because of their proximity to land seven months of altimeter comparisons were obtained during the geosat geodetic mission for the periods may august and october december 1985 only geosat data within 150 km of buoy locations were accessed this resulted in 1166 wind speed and significant wave height pairs an error analysis was performed to better understand the differences between altimeter and buoy derived results and to establish consistency between the two sets of measurements the following error sources were identified and quantified in terms of their impact on wind speed and significant wave height uncertainties 1 inaccuracies due to buoy instrumentation 2 errors resulting from temporal and spatial separations 3 errors arising from averaging of the buoy data in time and averaging of altimeter data over its footprint and 4 altimeter instrumentation errors four algorithms relating altimeter radar cross section to ocean surface wind speed were investigated the brown algorithm brown et al 1981 and the smoothed form of the algorithm of brown et al goldhirsh and dobson 1985 were found to give the smallest rms errors these were 1 7 m s and less for a maximum altimeter track buoy separation of 50 km for most cases considered this uncertainty agreed with the error obtained from the error analysis significant wave heights measured by the altimeter were found to be in agreement with buoy derived values to within 0 5 m rms this value was also found to be in agreement with that derived from the error analysis the measurement goals for geosat were 1 8 m s rms for wind speeds from 1 m s to 18 m s and 0 5 m rms for significant wave height or 10 whichever is greater frain et al 1985 these goals were met for the range of wind speeds compared

arecibo radar mapping of the lunar poles a search for ice deposits the arecibo 12 6 centimeter wavelength radar system was used to image the polar regions of the moon at a resolution of 125 meters in a search for ice deposits in areas of possible permanent shadow from the sun no areas greater than 1 square kilometer were found with high radar backscatter cross sections and high circular polarization ratios properties suggestive of the presence of ice a number of areas smaller than 1 square kilometer were found with these properties but optical images from spacecraft missions have shown some of these features to be in sunlight arecibo radar images of sinus iridum at latitude 47 n also showed a number of small features with similar properties the coincidence of some of these features with the radar facing slopes of craters and their presence in sunlit areas suggests that very rough surfaces rather than ice deposits are responsible for their unusual radar properties