effects of rupture complexity on local tsunami inundation implications for probabilistic tsunami hazard assessment by example we investigated the influence of earthquake source complexity on the extent of inundation caused by the resulting tsunami we simulated 100 scenarios with collocated sources of variable slip on the hikurangi subduction interface in the vicinity of hawke s bay and poverty bay in new zealand and investigated the tsunami effects on the cities of napier and gisborne rupture complexity was found to have a first order effect on flow depth and inundation extent for local tsunami sources the position of individual asperities in the slip distribution on the rupture interface control to some extent how severe inundation will be however predicting inundation extent in detail from investigating the distribution of slip on the rupture interface proves difficult assuming uniform slip on the rupture interface in tsunami models can underestimate the potential impact and extent of inundation for example simulation of an mw 8 7 to mw 8 8 earthquake with uniform slip reproduced the area that could potentially be inundated by equivalent nonuniform slip events of mw 8 4 deaggregation to establish the contribution of different sources with different slip distributions to the probabilistic hazard cannot be performed based on magnitude considerations alone we propose two predictors for inundation severity based on the offshore tsunami wavefield using the linear wave equations in an attempt to keep costly simulations of full inundation to a minimum

simulation of tsunami hazards affecting the east cape region new zealand the east coast of new zealand is known for being exposed to a variety of tsunami sources both those arising from the nearby hikurangi subduction zone and its associated crustal faults and those arising from more distant parts of the pacific using numerical simulations with a parallelized computer model we assess the tsunami inundation hazard posed to the most populated coastal communities on the east coast of the east cape region new zealand which had not been evaluated before our tsunami inundation hazard study is based on severe but realistic scenario events from a selection of local and distant earthquake tsunami sources such modelling covers a gap in knowledge caused by the short historical record of tsunamis in this region covering 200 years and the sparse observations of historical tsunamis due to a largely rural population we identify that the worst flooding is often not associated with the first wave arrivals and that coastal oscillations can last a long time in distant events the modelling results allow us to determine typical characteristics of the pattern of flooding specific to an area this information is important for emergency planning and preparedness

a full coverage high resolution topographic model of greenland computed from a variety of digital elevation data in this paper a new high resolution elevation model of greenland including the ice sheet as well as the ice free regions is presented it is the first published full coverage model computed with an average resolution of 2 km and providing an unprecedented degree of detail the topography is modeled from a wide selection of data sources including satellite radar altimetry from geosat and ers 1 airborne radar altimetry and airborne laser altimetry over the ice sheet and photogrammetric and manual map scannings in the ice free region the ice sheet model accuracy is evaluated by omitting airborne laser data from the analysis and treating them as ground truth observations the mean accuracy of the ice sheet elevations is estimated to be 12 13 m and it is found that on surfaces of a slope between 0 2 and 0 8 corresponding to approximately 50 of the ice sheet the model presents a 40 improvement over models based on satellite altimetry alone on coastal bedrock the model is compared with stereo triangulated reference points and it is found that the model accuracy is of the order of 25 35 m in areas covered by stereo photogrammetry scannings and between 200 and 250 m elsewhere

explicit numerical diffusion in the wrf model abstract diffusion that is implicit in the odd ordered advection schemes in early versions of the advanced research core of the weather research and forecasting wrf model is sometimes insufficient to remove noise from kinematical fields the problem is worst when grid relative wind speeds are low and when stratification is nearly neutral or unstable such as in weakly forced daytime boundary layers where noise can grow until it competes with the physical phenomena being simulated one solution to this problem is an explicit sixth order numerical diffusion scheme that preserves the wrf model s high effective resolution and uses a flux limiter to ensure monotonicity the scheme and how it was added to the wrf model are explained the scheme is then demonstrated in an idealized framework and in simulations of salt breezes and lake breezes in northwestern utah

surface mass balance of the greenland ice sheet from climate analysis data and accumulation runoff models we used surface climate fields from high resolution 0 56 0 56 european centre for medium range weather forecasts ecmwf operational analyses 1992 98 together with meteorological and glaciological models of snow accumulation and surface meltwater runoff retention to produce novel maps of greenland ice sheet gis net accumulation net runoff and surface mass balance smb we compared our runoff maps with similar scaled runoff melt minus refreezing maps based on passive microwave satellite data our gross spatial temporal patterns of runoff compared well with those from the satellite data although amounts of modelled runoff are likely too low mean accumulation was 0 287 0 307 m a 1 and mean runoff was 0 128 0 151 m a 1 averaged across the w abdalati t l mote gis mask corresponding mean smb was 0 159 0 156 m a 1 with considerable interannual variability standard deviation 0 11 m a 1 primarily due to variations in runoff considering best estimates of current iceberg calving overall the gis is probably currently losing mass our study shows great promise for meaningfully modelling smb based on forthcoming second generation ecmwf re analysis era 40 data and comparing the results with ongoing laser radar measurements of surface elevation this should help elucidate to what extent surface elevation changes are caused by short term smb variations or other factors e g ice dynamics

the effects of thermal maturity on distributions of dimethylnaphthalenes and trimethylnaphthalenes in some ancient sediments and petroleums abstract the distributions of di and trimethylnaphthalenes in two sedimentary sequences from western australia have been examined by capillary gas chromatography and combined gas chromatography mass spectrometry a general decrease was observed in the relative proportions of dimethylnaphthalenes and trimethylnaphthalenes with increasing thermal maturity similar trends were also observed for six crude oils which have very different ratios of ethylcholestane epimers indicating very different thermal histories these results suggest that changes in the relative abundances of certain methyl substituted naphthalenes may be useful indicators of thermal maturity of sedimentary organic matter and the use of a number of isomer ratios is illustrated

global to regional nested grid climate simulations in the gfdl high resolution atmospheric model abstracta two way nested grid version of the geophysical fluid dynamics laboratory high resolution atmosphere model hiram has been developed that uses simple methods for providing nested grid boundary conditions and mass conserving nested to global communication nested grid simulations over the maritime continent and over north america were performed each at two different resolutions a 110 km mean grid cell width refined by a factor of 3 and a 50 km mean grid cell width refined by a factor of 2 nested grid simulations were compared against uniform resolution simulations and against reanalyses to determine the effect of grid nesting on both the modeled global climate and the simulation of small scale features orographically forced precipitation was robustly found to be simulated with more detail and greater realism in a nested grid simulation compared with when only the coarse grids were simulated alone tropical precipitation biases were reduced in the maritime continent region when a nested grid

precipitation over greenland and its relation to the north atlantic oscillation the equation method based on an equivalent isobaric geopotential height in coordinates has been used to retrieve the precipitation over greenland this approach is designed to accurately represent the topographic effects of the greenland ice sheet on atmospheric motion and precipitation the 11 year mean precipitation from 1985 to 1996 over all of greenland is 376 mm yr 1 which is close to the long term mean precipitation of 346 mm yr 1 estimated from glaciological data the precipitation over all of greenland shows that the largest value in 1986 is 472 mm yr 1 and the smallest value in 1995 is 309 mm yr 1 the major interannual variability of the atmospheric circulation in the north atlantic can be represented by the variation of the north atlantic oscillation nao index which is most pronounced during winter it is found that if the nao index increases the total precipitation over greenland decreases and vice versa the correlation coefficient between these two series for 1985 1995 is 0 75 the mean precipitation over southern greenland where the majority of precipitation falls is more closely related to the nao index in winter and their correlation coefficient is 0 80 this relationship can be understood from the composite maps of sea level pressure and greenland precipitation for the high and low index months during months of high nao index values the icelandic low is strong during months of low nao index values the monthly mean low is located to the southwest of greenland over the labrador sea precipitation amounts over the southeast coast of greenland are about 100 mm larger during the low nao index months than the high nao index months precipitation over all of greenland during the low nao index months is higher there are significant downward trends in annual precipitation from 1985 1995 for all of greenland and its southern and central west coastal regions amounting to about 3 per year

a grid refinement based approach for modeling the convective boundary layer in the gray zone algorithm implementation and testing abstracta grid refinement based method is implemented in a community atmospheric model to improve the representation of convective boundary layer cbl turbulence on gray zone i e o 1 km grids at this resolution cbl convection is partially resolved and partially subgrid scale sgs such that neither traditional mesoscale planetary boundary layer pbl schemes nor sgs closures for large eddy simulations less are appropriate the proposed method utilizes two way interactive nesting to refine the horizontal resolution of the unstable surface layer of the daytime cbl sgs turbulent mixing in the fine nest and coarse parent grids are parameterized by an les turbulence closure and a pbl scheme respectively the method does not rely on predetermined empirical functions to introduce grid scale dependency and in theory works with any pbl scheme compared to the stand alone gray zone simulation the proposed approach shows improvements in terms of higher order statistics the timing of the onset of re

a biomarker study of immature crude oils from the shengli oilfield people s republic of china abstract a suite of crude oils from the shengli oilfield in northwestern china was subjected to detailed chemical analysis crude oils in this suite believed to be derived from source rocks deposited under fresh brackish and saline environments have chemical compositions and biological marker compounds indicative of immature source rocks in this respect the crude oils are unusual apparently having been formed and expelled from source rocks that have been subjected only to mild thermal stress prior to the main zone of petroleum generation

kerogen asphaltene sulfur relationships in sulfur rich monterey oils abstract monterey oils in the santa maria basin onshore and offshore are generally low maturity oils because of low thermal exposure relatively shallow burial for short times they are generated as heavy high sulfur oils because of the composition of the unusual type ii source kerogens which are exceptionally rich in organic sulfur 8 14 these high sulfur kerogens which we designate type ii s appear to generate oil at significantly lower thermal exposures than ordinary type ii kerogens with less than 6 s in contrast to common type ii kerogens which generate oil largely by cleavage at oxygen bridge groups and carbon carbon bonds eliminating co2 h2o and hydrocarbon fragments type ii s kerogens have an additional complement of weak bonds associated with bound sulfur the preferential cleavage at weak sulfur linkages tends to produce larger fragments leading to high initial amounts of asphaltenes resins and sulfur rich aromatics together with smaller amounts of saturated hydrocarbons elemental analyses of monterey kerogens and asphaltenes clearly support the concept that the asphaltenes are essentially fragments of kerogen cleaved sufficiently to be soluble or peptized in this heavy oil system solubilization of asphaltenes is attributed to their interactions with the abundant resins and aromatics this sysstem is sufficiently stable under source and reservoir conditions to allow expulsion and migration for reasonable distance without significant fractionation or changes in gross properties initial asphaltenes have essentially the same atomic h c ratios as the source kerogen but have significantlyy lower o c ratios and slightly lower s c ratios the n c ratios are nearly the same for kerogens and their derived asphaltenes with increasing maturity the h c ratios in asphaltenes decrease much like maturation changes in kerogen the s c ratio also decreases significantly however the o c ratios initially low in asphaltenes and n c ratios increase slightly due to material balance caused by other losses these element composition and atomic ratio relationships allow some important inferences concerning source kerogen composition from analysis of asphaltenes alone this can be useful when potential source rock samples are not available for analysis and or when a choice between alternate source rock possibilities must be made

influence of sea ice treatment in a regional climate model on boundary layer values in the fram strait region abstract the influence of two simple descriptions for the sea ice distribution on boundary layer values is investigated by comparing model results from the regional climate model remo with measured data in the fram strait in april 1999 one method for determining the sea ice distribution in remo is to diagnose the sea ice cover from the prescribed surface temperature and allow each grid cell to be either completely free of ice or completely covered by ice remo original the other one is to employ a partial sea ice concentration in each remo grid cell with the input data derived from satellite data remo partial surface fluxes are average values of the ice and water partial fluxes there is a clearly better agreement between measured and simulated surface and boundary layer temperatures and humidities when using remo partial compared to remo original the closed ice cover in remo original leads to downward sensible heat fluxes over ice whereas the ice cover with leads and polynyas in remo partial lead

evaluation of recent precipitation studies for greenland ice sheet the retrieval of an accurate spatial and temporal record of contemporary greenland precipitation is a uniquely challenging task because of the extreme variability in both atmospheric processes and the resulting precipitation distribution over relatively small spatial scales a comparison of precipitation data sets composed of monthly mean values from recent studies shows a convergence on the general features of the long term spatial patterns but substantial disagreement on the temporal variability both regionally and for all of greenland there is general agreement on a long term greenland average of about 35 cm yr 1 and on long term values for regional scales although differences for outlying data sets exceed 50 of the observed glaciological estimate for particular regions a fundamental problem is the inadequate topographic representation of greenland in the numerical analyses nearly all of the data sets are overly dry for high elevation areas as seen from comparisons with glaciological observations from summit the east central region of greenland is found to be particularly susceptible to the temporal discontinuities in data sets which employ operational analyses in contrast there is strong agreement among all methods on the temporal variability for the west central region over a 15 year period from the comparison it is concluded that none of the data sets is able to capture all of the regional scale features in general however the deficiencies of each data set are readily identifiable from comparison and evaluation in the context of circulation features agreement among the methods on particular regions and timescales gives increased confidence in drawing conclusions related to aspects of greenland s precipitation climatology in particular an enhanced precipitation retrieval method is found to be less susceptible to data artifacts than other methods using operational analyses in the north anomalously high precipitation is associated with cyclonic development near the fram strait for west central greenland the close agreement among methods is related to the dominant contribution of the mean circulation

recent greenland accumulation estimated from regional climate model simulations and ice core analysis the accumulation defined as precipitation minus evaporation over greenland has been simulated with the high resolution limited area regional climate model hirham4 applied over an arctic integration domain this simulation is compared with a revised estimate of annual accumulation rate distribution over greenland taking into account information from a new set of ice core analyses based on surface sample collections from the north greenland traverse the region with accumulation rates below 150 mm yr21 in central northwest greenland is much larger than previously assumed and extends about 500 km farther to the south it is demonstrated that good agreement between modeled and observed regional precipitation and accumulation patterns exists particularly concerning the location and the values of very low accumulation in the middle of greenland the accumulation rates in the northern part of greenland are reduced in comparison to previous estimates these minima are connected with a prevailing blocking high over the greenland ice sheet and katabatic wind systems preventing humidity transports to central greenland the model reasonably represents the synoptic situations that lead to precipitation maxima of precipitation and accumulation occur at the southwestern and southeastern coasts of greenland and are connected with cyclonic activity and the main storm tracks around greenland the central region of the greenland ice sheet acts as a blocking barrier on moving weather systems and prohibits cyclones moving from west to east across this region and thus prevents moisture transports

trimethylnaphthalenes in crude oils and sediments effects of source and maturity abstract three sedimentary sequences and a number of crude oils have been analysed for trimethylnaphthalenes tmns using gas chromatography the sediments were found to contain enhanced relative abundances of 1 2 5 tmn and 1 2 7 tmn in samples of cretaceous age and younger this was especially pronounced in lower maturity sediments containing type iii organic matter older samples containing type iii organic matter were found to contain enhanced relative abundances of 1 2 5 tmn and lower relative abundances of 1 2 7 tmn 1 2 7 tmn appears to be derived directly from the structural degradation of oleanane type triterpenoids present in angiosperms and as such is proposed as a marker for this class of plant and indirectly therefore also for samples deposited since the early cretaceous the crude oils have been classified according to their trimethylnaphthalene compositions this classification enables crudes of higher plant origin to be identified and to be further classified according to whether the organic matter pre dated or post dated the evolution of angiosperms

severe downslope windstorm calculations in two and three spatial dimensions using anelastic interactive grid nesting a possible mechanism for gustiness abstract the clark nonhydrostatic anelastic code is extended to allow for interactive grid nesting in both two and three spatial dimensions tests are presented which investigate the accuracy of three different quadratic interpolation formulae which are used to derive boundary conditions for the fine mesh model application of the conservation condition of kurihara and others is shown to result in significant improvements in the treatment of interactive nesting a significant improvement in the solutions for interactive versus parasitic nesting is also shown in the context of forced gravity wave flow this result for the anelastic system is in agreement with the earlier results of phillips and shukla who considered the hydrostatic shallow water system of equations the interactive nesting model is applied to the simulation of the severe downslope windstorm of 11 january 1972 in boulder using both two and three spatial dimensions the three dimensional simulation results in a gustiness signature in the

a mesoscale analysis method for surface potential temperature in mountainous and coastal terrain abstract a technique is developed to anisotropically spread surface observations in steep valleys the goal is to create an improved objective analysis for the lowest terrain following numerical weather prediction nwp model level in mountainous terrain the method is a mother daughter md approach where the amount of information transferred from one grid point the mother to all neighboring grid points the daughters depends on elevation differences the daughters become mothers and further share information with their neighboring grid points this iterative method allows information to follow valleys around ridges while reducing spread over the ridge top the method is further refined to account for land sea anisotropy this approach is tested in the objective analyses of surface potential temperatures over the steep mountainous and coastal terrain of southwestern british columbia canada analysis results are compared with other existing schemes using the advanced regional prediction system data

an idealized comparison of one way and two way grid nesting abstract most mesoscale models can be run with either one way parasitic or two way interactive grid nesting this paper presents results from a linear 1d shallow water model to determine whether the choice of nesting method can have a significant impact on the solution two way nesting was found to be generally superior to one way nesting the only situation in which one way nesting performs better than two way is when very poorly resolved waves strike the nest boundary a simple filter is proposed for use exclusively on the coarse grid values within the sponge zone of an otherwise conventional sponge boundary condition bc the two way filtered sponge bc gives better results than any of the other methods considered in these tests results for all wavelengths were found to be robust to other changes in the formulation of the sponge boundary particularly with the width of the sponge layer the increased reflection for longer wavelength disturbances in the one way case is due to a phase difference bet

a comparison of mesh refinement in the global mpas a and wrf models using an idealized normal mode baroclinic wave simulation abstractidealized normal mode baroclinic wave simulations are conducted to examine the impact of continuous mesh refinement compared with stepwise changes in resolution using nested grids the nested grid results are produced using the advanced research weather research and forecasting wrf arw model hereafter arw and the continuous refinement results are produced using the atmospheric component of the model for prediction across scales atmosphere mpas a for the nested domain simulations with the arw variants of both one way and two way nesting techniques are examined significant reflection and distortion of waves are evident in results using one way nesting with the error increasing with decreasing boundary update frequency with continuous updating of the boundary conditions in one way and two way nesting wave distortion is still evident near the lateral boundaries but the distortion is much less than with infrequent boundary updates the conformal voronoi meshes in mpas provide a much smoothe

new precipitation and accumulation maps for greenland annual total precipitation and the annual accumulation on the greenland ice sheet are evaluated and presented in two maps the maps are based on accumulation measurements of 25 1 pits and cores obtained from the upper accumulation zone and precipitation measurements made at 35 meteorological stations in the coastal region to construct the accumulation map the annual precipitation was split into solid and liquid precipitation components annual total precipitation exceeding 2500 mm w e occurs on the southeastern tip of greenland while the minimum precipitation is estimated to occur on the northeastern slope of the ice sheet the mean annual precipitation for all of greenland is 340 mm w e the largest annual accumulation of about 1500 mm w e is found on the glaciers in the southeastern corner of greenland while the smallest accumulation is found on the northeastern slope of the ice sheet west of danmarkshavn the mean accumulation on the greenland ice sheet is estimated at 310 mm w e the regional difference in accumulation is examined with respect to the 850 hpa m bar level circulation the present surface topography is found to play an important role in determining regional accumulation on the ice sheet

effects of source thermal maturity and biodegradation on the distribution and isomerization of homohopanes in petroleum abstract the distributions of c31 c35 17 21 h homohopanes in marine petroleums can be used to describe redox conditions in the source rock depositional environment for example high c35 homohopane indices c35 c31 c35 are typical of petroleums generated from source rocks deposited under anoxic marine conditions where the c35 backbone of the precursor bacteriohopanetetrol is preferentially preserved homohopane distributions have been used to distinguish petroleums from different organic facies of the same source rock homohopane distributions are altered by secondary processes for example the c35 homohopane index decreases with increasing api gravity and thermal maturity of related oils from the monterey formation offshore california similar decreases in the homohopane index are observed for expelled oils from monterey source rock during hydrous pyrolysis biodegradation can result in selective loss of high or low molecular weight homologs apparently depending on the bacterial population in the reservoir bacterial demethylation of homohopanes appears necessary to explain 25 norhopanes in at least one biodegraded oil hydrous pyrolysis studies of the phosphatic and siliceous members in the monterey formation show that identical heating conditions result in different homohopane c 22 epimer ratios furthermore a reversal in the trend of the epimer ratio at high experimental temperatures is observed for the phosphatic but not for the siliceous lithology this could be caused by the combined effects of isomerization and differential thermal destruction of epimers at high temperatures possibly mediated by rock mineralogy