geochemical modelling of the principal source rocks of the barinas and maracaibo basins western venezuela this study presents a geochemical modelling of the principal source rocks in the western venezuelan basins the area covers more than 100 000 km sup 2 and includes lake maracaibo and barinas basins the geochemical modelling recognizes three source rocks 1 a principal k3 k4 k5 cretaceous sequences represented by la luna capacho and navay formations 2 a secondary corresponding to the t4 oligocene sequence represent by the carbonera formation and 3 an accessory source rock k7 k8 paleocene sequences represented by the carbonaceous shales and coals of the orocue group and marcelina formation three periods of hydrocarbon expulsion were defined for la luna formation early eocene late eocene middle miocene early miocene and early miocene holocene and a principal period of hydrocarbon expulsion for orocue group and carbonera formation plio pleistocene and middle miocene plio pleistocene the 90 of hydrocarbons generated correspond to the principal source rock la luna formation and the 10 to tertiary source rocks carbonera formation and orocue group five petroleum systems were identified lake maracaibo southwest of the lake maracaibo basin the lara nappes the extensive basins of eastern zulia and the barinas subbasin

a spectrum analysis of synoptic scale disturbances in the itcz abstract spectral characteristics of convective signals in synoptic scale disturbances along the intertropical convergence zone itcz are examined using a 20 yr daily outgoing longwave radiation dataset a new analysis method which combines conventional wavenumber frequency spectrum analysis and wavelet analysis is developed to explore the longitudinal seasonal and interannual variations in these disturbances within the itcz whose seasonal migration varies in different parts of the tropics the analysis focuses on three longitudinal sectors where the itcz can be clearly identified the western central pacific the central eastern pacific and the atlantic west africa the most striking results are the evident zonal variability in the spectral properties of westward propagating synoptic scale disturbances the zonal variability exists not only in their dominant frequencies and zonal wavenumbers but also in their seasonal and interannual variations eastward propagating synoptic scale disturbances in

the structure and annual variation of antisymmetric fluctuations of tropical convection and their association with rossby gravity waves abstract the signature of 4 5 day period rossby gravity waves is searched for in the tropical convection field across the indian pacific oceans the convergence divergence field of these waves in the lower troposphere is anticipated to produce an antisymmetric fluctuation in tropical convection antisymmetric fluctuations of tropical convection are shown to exhibit a pronounced spectral peak at a 4 5 day period only during boreal fall and only within about 30 longitude of the date line the peak amplitude occurs around 7 5 latitude these fluctuations propagate westward at 15 20 m s 1 with zonal wavelength of about 7000 9000 km the fluctuations of convection are coherent and out of phase with the equatorial meridional wind which also exhibits a pronounced spectral peak at a 4 5 day period in the lower troposphere near the date line the antisymmetric zonal wind also is strongly coherent with the antisymmetric convective fluctuations in this region the horizontal distributions of the 4 5 day power an

biodegradation of sedimentary organic matter associated with coalbed methane in the powder river and san juan basins u s a the powder river basin and san juan basin u s a are two of the most productive coalbed methane reserves in the world of particular interest is the microbial biodegradation of coal beds associated with this natural gas production biogenic methane production is indicated as a significant component to the total gas resources in the san juan basin and as the nearly sole source for the shallow coals of the powder river basin molecular and isotopic signatures indicate a microbial origin for the gas geochemical characteristics of formation waters such as elevated alkalinity and 13c enriched dissolved inorganic carbon dic further support extensive microbial degradation of coal organic matter associated with methanogenesis extractable organic matter isolated from coals in both basins point to patterns of hydrocarbon biodegradation in coals restricted to specific depths to some extent biodegradation patterns are similar to those observed in methanogenic biodegraded black shales of the mid continent of the united states specifically both coals and shales exhibit near quantitative removal of straight chain and acyclic isoprenoid hydrocarbons however loss of aromatic hydrocarbons in the coals proceeds prior to the extensive removal of the saturated hydrocarbons in contrast to what is conventionally observed in biodegraded petroleum systems or in black shales in addition previous thermal maturation histories in both the fruitland and fort union coalbed methane systems have little impact on more recent hydrocarbon biodegradation instead localized hydrologic conditions and subsurface geology likely play important roles in controlling the extents of biodegradation and methanogenesis these results suggest that biodegradation of hydrocarbons coupled with methanogenesis may develop regardless of organic matter source across a range of inherited thermal maturities

upscale impact of mesoscale disturbances of tropical convection on 2 day waves abstractwestward propagating 2 day waves with embedded mesoscale disturbances contribute a large portion of synoptic variability of tropical convection over the western pacific it is of crucial im

a case study of an outbreak of twin tropical cyclones abstract previous studies have found that twin tropical cyclogenesis typically occurs 2 3 times a year in the pacific ocean during october 1997 however three sets of twin tropical cyclones developed in the central pacific within a single month tropical cyclone archives indicate that this is the only such outbreak from 1969 to 2006 this case study explores the background and synoptic conditions that led to this unique event all three twin tropical cyclogenesis events occurred within a broad and long lasting envelope of warm water low surface pressure active convection and weak or easterly vertical shear westerly winds at the equator and trade easterlies farther poleward created strips of cyclonic vorticity through a deep layer a low pass filter showed that these favorable conditions shifted eastward with time at 1 2 m s 1 in addition to the gradual eastward movement the equatorial westerlies and convection were modulated by higher frequency westward propagation these anomalies appear to have

resonant forcing of mixed layer inertial motions by atmospheric easterly waves in the northeast tropical pacific abstract westward propagating atmospheric easterly waves contribute to much of the variability of the low level wind fields within the northeast tropical pacific with the dominant period of these waves 3 5 days close to the local inertial period 2 4 days at 12 n to 5 7 days at 5 n there is the expectation that the associated winds may resonantly force mixed layer inertial motions in this region the authors test this hypothesis using a simple slab model and roughly 4 yr of wind data from four noaa tropical atmosphere ocean eastern pacific investigation of climate processes tao epic buoys along 95 w at 12 10 8 and 5 n the degree of resonance is determined by comparing model simulations using observed wind stress with simulations forced with reversed rotation wind stress results strongly indicate that pacific easterly waves pews resonantly force inertial motions in the region this resonance shows both significant seasonality and latitudinal dependence that appears to be related to the me

tracking and mean structure of easterly waves over the intra americas sea abstract easterly waves ews are prominent features of the intertropical convergence zone itcz found in both the atlantic and pacific during the northern hemisphere summer and fall where they commonly serve as precursors to hurricanes over both basins a large proportion of atlantic ews are known to form over africa but the origin of ews over the caribbean and east pacific in particular has not been established in detail in this study reanalyses are used to examine the coherence of the large scale wave signatures and to obtain track statistics and energy conversion terms for ews across this region regression analysis demonstrates that some ew kinematic structures readily propagate between the atlantic and east pacific with the highest correlations observed across costa rica and panama track statistics are consistent with this analysis and suggest that some individual waves are maintained as they pass from the atlantic into the east pacific whereas others are generated locally in the caribbean a

relationships among geochemical indices of coal and carbonaceous materials and implication for hydrocarbon potential evaluation a worldwide dataset of organic material from 553 samples belonging to coal and carbonaceous materials was used to analyze the evolution of hydrogen index hi and bitumen index bi with increasing thermal maturity basic statistical analyses were applied to detect the boundary lines of himax and bimax in delineating the upper and lower limits of the hi and bi bands for the majority of samples in addition cross plots of hi or bi versus maturity ro and tmax also provide criteria for defining the himax and bimax boundary lines the constructed hi and bi bands are broad at low maturities and become narrower with increasing thermal maturities the petroleum generation potential is completely exhausted at the vitrinite reflectance of 2 0 2 2 or tmax of 510 520 c an increase in hi implies extra petroleum generation which was related to changes in structure of organic materials a declining bi means that the oil expulsion window starts to occur at the vitrinite reflectance range of 0 75 1 05 the petroleum potential can be divided into four different areas based on the cross plot of hi versus ro the highest petroleum potential area is located in section ii with ro 0 6 1 0 and hi 100 the oil generation potential is rapidly exhausted at section iii with ro 1 0 this result is also in accordance with the result of curve regression of hi versus ro based on 80 samples with ro 1 02 3 43 r2 0 72 overall the total oil window can be extended up to ro 1 25 1 95 finally in the cross plots of s1 versus s2 shale or c shale exhibits a higher and slowly decreased slope compared with a lower and then sharply increased slope of coal samples which is attributable to their compositional difference in organic material

effects of zonal flows on equatorially trapped waves abstract linear shallow water equations are employed to study the effects of basic zonal flows on equatorially trapped waves analytical solutions are obtained for constant basic zonal flows it is shown that changes in the wave structures due to the non doppler effect of the basic zonal flow are considerable for the rossby wave moderate for the westward propagating mixed rossby gravity wave but negligible for the other equatorial waves the rossby wave and the westward propagating mixed rossby gravity wave possess greater eigenfrequencies and are less trapped in westerlies than in easterlies the dependence of the rossby wave structure upon the basic zonal flow is interpreted in terms of potential vorticity conservation in basic zonal flows with meridional shears the eigenfrequencies are found to be larger in equatorial easterlies than in equatorial westerlies for the westward propagating waves but smaller for the eastward propagating waves while the meridional structures of the eastward propagating

the dynamics of the west african monsoon part v the detection and role of the dominant modes of convectively coupled equatorial rossby waves abstract this study is the last in a series of papers addressing the dynamics of the west african summer monsoon at intraseasonal time scales between 10 and 90 days the signals of convectively coupled equatorial rossby er waves within the summer african monsoon have been investigated after filtering noaa outgoing longwave radiation olr data within a box delineated by the dispersion curves of the theoretical er waves two families of waves have been detected in the 10 100 day periodicity band by performing a singular spectrum analysis on a regional index of er filtered olr for each family the first eof mode has been retained to focus on the main convective variability signal within the periodicity band of 30 100 days an er wave pattern with an approximate wavelength of 13 500 km has been depicted this er wave links the mjo mode in the indian monsoon sector with the main mode of convective variability over west and central africa this confirms the investigations carried out in previous studies wi

synoptic scale disturbances near the equator abstract a spectral analysis of winds analyzed and initialized at the european centre for medium range weather forecasts reveals an abundance of power in the 850 mb meridional wind along the equator with periods near four days the power is mostly in the westward propagating component using high pass filtered data it is shown that the waves have westward phase and eastward group propagation relative to the mean wind the longest wavelengths are found over the pacific ocean while the shortest are found over the convectively variable regions of indonesia south america and africa mean phase speeds at 850 mb are positively correlated with the mean wind on the equator at 500 mb and below and negatively correlated with the mean wind above that level the effective advecting zonal wind of the disturbances seems to be the density weighted average of the lower troposphere the structure of the disturbances bears resemblance to the expected structure of an equatorially trapped mixed rossby gravity wave over t

horizontal and vertical structure of easterly waves in the pacific itcz abstract outgoing longwave radiation olr and low level wind fields in the atlantic and pacific intertropical convergence zone itcz are dominated by variability on synoptic time scales primarily associated with easterly waves during boreal summer and fall this study uses spectral filtering of observed olr data to capture the convective variability coupled to pacific easterly waves filtered olr is then used as an independent variable to isolate easterly wave structure in wind temperature and humidity fields from open ocean buoys radiosondes and gridded reanalysis products the analysis shows that while some pacific easterly waves originate in the atlantic most of the waves appear to form and strengthen within the pacific pacific easterly waves have wavelengths of 4200 5900 km westward phase speeds of 11 3 13 6 m s 1 and maximum meridional wind anomalies at about 600 hpa a warm moist boundary layer is observed ahead of the waves with moisture lofted quickly through the troposphere by deep co

multiscale organization of convection simulated with explicit cloud processes on an aquaplanet abstract this study investigated the multiscale organization of tropical convection on an aquaplanet in a model experiment with a horizontal mesh size of 3 5 km for a 10 day simulation and 7 km for a 40 day simulation the numerical experiment used the nonhydrostatic icosahedral atmospheric model nicam with explicit cloud physics the simulation realistically reproduced multiscale cloud systems eastward propagating super cloud clusters sccs contained westward propagating cloud clusters ccs sccs ccs had zonal sizes of several thousand hundred kilometers typical propagation speed was 17 10 m s 1 smaller convective structures such as mesoscale cloud systems mcs of o 10 km and cloud scale elements 16 km of o 100 km area was also reproduced planetary scale equatorial waves with wavelengths of 10 000 and 40 000 km had a major influence on the eastward propagation of the simulated scc destabilization east of the

impact of the madden julian oscillation on the summer west african monsoon in amip simulations at intraseasonal timescales convection over west africa is modulated by the madden julian oscillation mjo in this work we investigate the simulation of such relationship by 11 state of the art atmospheric general circulation models runs with prescribed observed sea surface temperatures in general the atmospheric model intercomparison project simulations show good skill in capturing the main characteristics of the summer mjo as well as its influence on convection and rainfall over west africa most models simulate an eastward spatiotemporal propagation of enhanced and suppressed convection similar to the observed mjo although their signal over west africa is weaker in some models in addition the ensemble average of models composites gives a better performance in reproducing the main features and timing of the mjo and its impact over west africa the influence on rainfall is well captured in both sahel and guinea regions thereby adequately producing the transition between positive and negative rainfall anomalies through the different phases as in the observations furthermore the results show that a strong active convection phase is clearly associated with a stronger african easterly jet aej but the weak convective phase is associated with a much weaker aej our analysis of the equatorial waves suggests that the main impact over west africa is established by the propagation of low frequency waves within the mjo and rossby spectral peaks results from the simulations confirm that it may be possible to predict anomalous convection over west africa with a time lead of 15 20 day

the madden julian oscillation recorded in early observations from the tropical rainfall measuring mission trmm a satellite data analysis is performed to explore the madden julian oscillation mjo focusing on the potential roles of the equatorial rossby er and kelvin waves measurements from the tropical rainfall measuring mission trmm precipitation radar pr and visible infrared scanner virs are analyzed in the frequency wavenumber domain to identify and ultimately filter primary low frequency modes in the tropics the space time spectrum of deep storm fraction estimated by pr and virs exhibits notable kelvin wave signals at wavenumbers 5 8 a distinct mjo peak at wavenumbers 1 7 and periods of about 40 days and a signal corresponding to the er wave these modes are separately filtered to study the individual modes and possible relationship among them in the time longitude space in 10 cases analyzed here an mjo event is often collocated with a group of consecutive kelvin waves as well as an intruding er wave accompanied with the occasional onset of a stationary convective phase the spatial and temporal relationship between the mjo and kelvin wave is clearly visible in a lag composite diagram while the ubiquity of the er wave leads to a less pronounced relation between the mjo and er wave a case study based on the geostationary meteorological satellite gms imagery together with associated dynamic field captures the substructure of the planetary scale waves a cross correlation analysis confirms the mjo related cycle that involves surface and atmospheric parameters such as sea surface temperature water vapor low clouds shallow convection and near surface wind as proposed in past studies the findings suggest the possibility that a sequence of convective events coupled with the linear waves may play a critical role in mjo propagation an intraseasonal radiative hydrological cycle inherent in the local thermodynamic conditions could be also a potential factor responsible for the mjo by loosely modulating the envelope of the entire propagation system

geochemical truths in large data sets i geochemical screening data abstract organic geochemistry especially when undertaken on a well by well or outcrop by outcrop basis arguably lacks statistically significant numbers of analyses to establish reliable trends can a reliable vitrinite reflectance vs depth trend be established from say 12 analysed samples when the number of analysed samples are in the hundreds or even thousands much clearer general trends are established and anomalous measurements more readily recognised interpretation of anomalies is itself highly instructive but forms another paper in this paper a global data set of some 5000 source rock samples is assembled from the open literature and released data e g open file reports and the results discussed to produce practical oil industry interpretations from basic screening data a complex conclusion can be extracted from simple data sets and are supported by mass balance and kinetic theory it is concluded that interpretation always falls back on a comparison of new data with pre existing knowledge in the form of tables and plots total organic carbon toc values are generally log normally distributed so that using mean standard deviation values will under estimate the upside potential when fed into risked probabilistic hydrocarbon charge prediction models kerogen type is initially best determined using plots of rock eval s 2 vs toc rather than the hydrogen index hi s 2 toc vs oxygen index oi s 3 toc or pseudo van krevelen plot the intercept of the s 2 vs toc plot predicts the average dead carbon inertinite content of the source rock set with the slope corresponding to the hydrogen index of the labile component hi l maturity trends of the hydrogen index vs t max or r o show reversals at high maturities as supported by the kinetics of the thermal breakdown of the three standard kerogen types at elevated maturities type iii kerogens have higher hydrogen indices than types i and ii kerogens a feature that must be taken into account when correcting mature kerogens to their original hi values hi o the reduction in hydrogen index is a measure of generation with the corresponding increase in production index pi s 1 s 1 s 2 being effectively a measure of hydrocarbon retention a cross plot of hi vs pi can be interpreted in terms of expulsion efficiencies expelled generated minus retained hydrocarbon measured data support a pore saturation and or generation pressure driven process for expulsion and indicate a limiting pore saturation equivalent to a production index of 0 6 for rich 2 toc source rocks

combining palynofacies and petrography in the study of sub bituminous tropical coals a case history from lower tertiary coals in colombia abstract colombia contains large coal reserves of late cretaceous to cenozoic age in various sedimentary basins but little is known about their potential to generate hydrocarbons in western venezuela coals are known to be potential source rocks for oil and the vicinity of these coals with coal bearing basins in colombia has prompted new studies in colombian tropical coals to develop concepts about their hydrocarbon generating potential the paleogene amaga formation studied here although of limited geographical extension is an ideal field laboratory which contains low rank coal seams in which the transformation and preservation state of organic matter permits the assessment of environment and vegetation types existing at the time of peat formation several seams up to 1 m thick have been analyzed using both bulk seam samples and ply or lithotype samples it is demonstrated that bulk seam samples are not representative for a proper evaluation of the hydrocarbon generation potential of seams one needs to evaluate all lithotype assemblages within a seam proximate analysis and rock eval pyrolysis provide a rapid and cheap way to assess the generation potential of each lithotype the potentially interesting lithotypes can be further analyzed through the combination of petrographic and palynological observations these methods permit the comparison of coal macerals with the equivalent palynofacies constituents provided that a preparation technique especially designed for tropical sub bituminous tertiary coals is used the palynofacies technique has proved to be more accurate than petrography in determining the relative proportion of the potentially oil prone constituents macerals which can be hidden or difficult to identify in petrographic polished section moreover the comparison between resinite oil observed in petrography and resins identified in palynofacies may yield indications of early hydrocarbon generation this methodology provides a fully detailed inventory of coal properties with respect to hydrocarbon generation potential the use of palynofacies is an additional tool to apprehend the floral composition and paleoenvironment of coals thereby increasing the geological and geochemical database needed to evaluate their potential such a methodology may prove very important to assess the petroleum potential of thicker coal deposits in prospective petroleum provinces such as the cerrejon coals in northern colombia

scale interaction between tropical instability waves and low frequency oceanic flows 1 tropical instability waves tiws prevailing in the tropical pacific and atlantic oceans interact with the low frequency oceanic flow it is known that tiws act as negative feedback to enso through a thermal process in this study we examine the dynamical eddy feedback of tiws we show that in terms of physical processes the dynamical tiw feedback is very similar to the atmospheric synoptic eddy feedback in the extratropics for example the mean seasonal eddy vorticity flux of tiws can be largely explained by the left hand rule which states that eddy vorticity fluxes are predominantly directed toward the left hand side of the oceanic flow therefore they act as positive feedback to the low frequency oceanic flow we also show that the positive eddy feedback is obtained from eddy structure changes induced by the low frequency flow

the stratigraphic distribution of inertinite abstract the paper presents the results of an investigation into the stratigraphic distribution of inertinite in humic coals ranging from the silurian to the neogene periods this range equals the time span during which both land plants and atmospheric oxygen evolved the survey is based on a literature study of inertinite in coals covering a variety of depositional environments and climates in all continents the inertinite percentages listed in this paper have been arranged in stratigraphic order they are the mean values based on mineral free whole coal compilations maceral compositions listed in the literature for individual subsections have been averaged to represent complete coal seams beds although this might not have been always possible due to some ambiguity in the published record moreover not all of the published and unpublished information could be used because of poor sample description obscure geographic origin or insufficient stratigraphic information the results show that there have been times in the geological past e g during the late permian in which coals were particularly rich in inertinite compared with other times e g during much of the late tertiary in which many coals contained very little inertinite occasionally such primary global trends were modulated by a diffuse distribution of inertinite percentages that correspond to differences in climate depositional settings e g active orogenic margins versus tectonically inactive shelf margins and other local or regional variations although various mechanisms for the generation of inertinite have been proposed in the past the overall pattern in its stratigraphic distribution supports the notion of incomplete combustion as the main source of inertinite in coal this points to secular variations in the atmospheric oxygen content as an explanation for the global changes in the inertinite distribution while differential subsidence and climatically influenced reaction rates governed regional and local variations in inertinite percentages

organic petrology of paleocene marcelina formation coals paso diablo mine western venezuela tectonic controls on coal type abstract about 7 mt of high volatile bituminous coal are produced annually from the four coal zones of the upper paleocene marcelina formation at the paso diablo open pit mine of western venezuela as part of an ongoing coal quality study we have characterized twenty two coal channel samples from the mine using organic petrology techniques samples also were analyzed for proximate ultimate parameters forms of sulfur free swelling index ash fusion temperatures and calorific value six of the samples represent incremental benches across the 12 13 m thick no 4 bed the stratigraphically lowest mined coal which is also mined at the 10 km distant mina norte open pit organic content of the no 4 bed indicates an upward increase of woody vegetation and or greater preservation of organic material throughout the life of the original mire s an upward increase in telovitrinite and corresponding decrease in detrovitrinite and inertinite illustrate this trend in contrast stratigraphically higher coal groups generally exhibit a dulling upward trend the generally high inertinite content and low ash yield and sulfur content suggest that the paso diablo coals were deposited in rain fed raised mires protected from clastic input and subjected to frequent oxidation and or moisture stress however the two thinnest coal beds both 0 7 m thick are each characterized by lower inertinite and higher telovitrinite content relative to the rest of paso diablo coal beds indicative of less well established raised mire environments prior to drowning foreland basin paleocene coals of western venezuela including the paso diablo deposit and time correlative coal deposits of the tachira and merida andes are characterized by high inertinite and consistently lower ash and sulfur relative to eocene and younger coals of the area we interpret these age delimited coal quality characteristics to be due to water availability as a function of the tectonic control of subsidence rate it is postulated that slower subsidence rates dominated during the paleocene while greater foreland basin subsidence rates during the eocene miocene resulted from the loading of nappe thrust sheets as part of the main construction phases of the andean orogen south southeastward advance and emplacement of the lara nappes during the oblique transpressive collision of the caribbean and south american tectonic plates in the paleocene was further removed from the sites of peat deposition resulting in slower subsidence rates slower subsidence in the paleocene may have favored the growth of raised mires generating higher inertinite concentrations through more frequent moisture stress consistently low ash yield and sulfur content would be due to the protection from clastic input in raised mires in addition to the leaching of mineral matter by rainfall and the development of acidic conditions preventing fixation of sulfur in contrast peat mires of eocene miocene age encountered rapid subsidence due to the proximity of nappe emplacement resulting in lower inertinite content higher and more variable sulfur content and higher ash yield

convectively coupled kelvin waves and tropical cyclogenesis in a semi lagrangian framework abstractthis study examines how convectively coupled kelvin waves interact with the semi lagrangian circulation of easterly waves to modulate tropical cyclogenesis recent studies have shown that fewer tropical cyclones form in the three days before passage of the kelvin wave s peak convection and more develop in the three days thereafter separately other studies have identified the recirculation of moisture and vorticity within easterly waves using a semi lagrangian frame of reference that framework is achieved by subtracting the easterly wave phase speed from the earth relative winds this study combines these recent findings by testing whether the equatorial westerlies from kelvin waves can help close the semi lagrangian circulation past studies have shown that kelvin waves tilt westward with height in the troposphere such that equatorial westerlies build upward from the surface in the days following the convective peak this study shows that the easterly wave s semi lagrangian closed circulation gr

the association of the evolution of intraseasonal oscillations to enso phase abstract the pacific ocean intraseasonal kelvin wave is a leading oceanic mode that links intraseasonal tropical atmospheric variations with interannual variations in the coupled ocean atmosphere system this study considers the premise that these waves may evolve differently with their associated weather patterns during different phases of el nino southern oscillation enso if atmospheric and oceanic intraseasonal modes interact and evolve differently during various stages of enso this result may provide useful information with regard to the role of these intraseasonal processes in enso evolution this work utilizes signals of the oceanic kelvin wave as a statistical basis for a simple composite averaging technique that is applied during different phases of enso to objectively analyze the evolution of oceanic and the associated portions of atmospheric intraseasonal oscillations results confirm the above premise and suggest that coupling between kelvin waves and atmospheric convection evolves differen

characterization of coal derived hydrocarbons and source rock potential of coal beds san juan basin new mexico and colorado u s a coal beds are considered to be a major source of nonassociated gas in the rocky mountain basins of the united states in the san juan basin of northwestern new mexico and southwestern colorado significant quantities of natural gas are being produced from coal beds of the upper cretaceous fruitland formation and from adjacent sandstone reservoirs analysis of gas samples from the various gas producing intervals provided a means of determining their origin and of evaluating coal beds as source rocks the rank of coal beds in the fruitland formation in the central part of the san juan basin where major gas production occurs increases to the northeast and ranges from high volatile b bituminous coal to medium volatile bituminous coal rm values range from 0 70 to 1 45 on the basis of chemical isotopic and coal rank data the gases are interpreted to be thermogenic gases from the coal beds show little isotopic variation 13c1 values range 43 6 to 40 5 ppt are chemically dry c1 c1 5 values are 0 99 and contain significant amounts of co2 as much as 6 these gases are interpreted to have resulted from devolatilization of the humic type bituminous coal that is composed mainly of vitrinite the primary products of this process are ch4 co2 and h2o the coal generated methane rich gas is usually contained in the coal beds of the fruitland formation and has not been expelled and has not migrated into the adjacent sandstone reservoirs in addition the coal bed reservoirs produce a distinctive bicarbonate type connate water and have higher reservoir pressures than adjacent sandstones the combination of these factors indicates that coal beds are a closed reservoir system created by the gases waters and associated pressures in the micropore coal structure in contrast gases produced from overlying sandstones in the fruitland formation and underlying pictured cliffs sandstone have a wider range of isotopic values 13c1 values range from 43 5 to 38 5 ppt are chemically wetter c1 c1 5 values range from 0 85 to 0 95 and contain less co2 2 these gases are interpreted to have been derived from type iii kerogen dispersed in marine shales of the underlying lewis shale and nonmarine shales of the fruitland formation in the underlying upper cretaceous dakota sandstone and tocito sandstone lentil of the mancos shale another gas type is produced this gas is associated with oil at intermediate stages of thermal maturity and is isotopically lighter and chemically wetter at the intermediate stage of thermal maturity as compared with gases derived from dispersed type iii kerogen and coal this gas type is interpreted to have been generated from type ii kerogen organic matter contained in coal beds and carbonaceous shales of the fruitland formation has hydrogen indexes from rock eval pyrolysis between 100 and 350 and atomic h c ratios between 0 8 and 1 2 oxygen indexes and atomic o c values are less than 24 and 0 3 respectively extractable hydrocarbon yields are as high as 7 000 ppm these values indicate that the coal beds and carbonaceous shales have good potential for the generation of liquid hydrocarbons voids in the coal filled with a fluorescent material that is probably bitumen is evidence that liquid hydrocarbon generation has taken place preliminary oil source rock correlations based on gas chromatography and stable carbon isotope ratios of c15 hydrocarbons indicate that the coals and or carbonaceous shales in the fruitland formation may be the source of minor amounts of condensate produced from the coal beds at relatively low levelsof thermal maturity rm 0 7

an air sea coupled skeleton model for the madden julian oscillation this work is an extension and improvement of the minimal madden julian oscillation mjo skeleton model developed by majda and stechmann which can capture some important features of the mjo slow eastward propagation quadrupole vortex structure and independence of frequency on wavelength but is unable to produce unstable growth and selection of eastward propagating planetary waves with the addition of planetary boundary layer frictional moisture convergence these deficiencies can be remedied the frictional boundary layer selects the planetary scale eastward propagation as the most unstable mode but the dynamics remains confined to atmospheric processes only here the authors study the role of air sea interaction by implementing an oceanic mixed layer ml model of wang and xie into the mjo skeleton model in this new air sea coupled skeleton model the features of the original skeleton model remain additionally the air sea interaction under mean westerly winds is shown to produce a strong instability that selectively destabilizes the eastward propagating planetary scale waves although the cloud shortwave radiation seasurfacetemperature crs feedbackdestabilizesbotheastwardand westward modes theair sea feedback associated with the evaporation and oceanic entrainment favors planetary scale eastward modes over the western hemisphere where easterly background winds prevail the evaporation and entrainment feedbacks yield damped modes indicating that longitudinal variation of the mean surface winds plays an important role in regulation of the mjo intensity in addition to the longitudinal variation of the mean sea surface temperature or mean moist static stability this theoretical analysis suggests that accurate simulation of the climatological mean state is critical for capturing the realistic air sea interaction and thus the mjo

the influences of convectively coupled kelvin waves on multiscale rainfall variability over the south china sea and maritime continent in december 2016 abstractwe studied the scale interactions of the convectively coupled kelvin waves kws over the south china sea scs and maritime continent mc during december 2016 three kws were observed nea

the role of equatorial rossby waves in tropical cyclogenesis part ii idealized simulations in a monsoon trough environment abstract this is the second of two papers examining the role of equatorial rossby er waves in tropical cyclone tc genesis based on results from part i it is hypothesized that genesis resulting from the circulation of an er wave alone is uncommon and that the majority of er wave related genesis events occur when a sufficiently intense er wave interacts with a favorable background flow environment this paper examines this contention by performing a series of simulations in which er waves are imposed upon idealized background flows the background flows are designed to resemble a region of a monsoon trough mt a flow feature observed at certain times of the year in all of the tc basins and most dramatically in the western north pacific basin it is believed that er wave interactions with the mt may speed up the internal breakdown genesis mechanism of the mt or even result in genesis when the mt is too weak to breakdown from in situ processes alone the latter scenario is examined here when just

observations of a convectively coupled kelvin wave in the eastern pacific itcz abstract a case study of a convectively coupled kelvin wave in the eastern pacific intertropical convergence zone itcz is presented as observed during the 1997 pan american climate studies pacs tropical eastern pacific process study tepps the large scale convective envelope associated with this disturbance with a zonal scale of approximately 1000 2000 km propagates eastward at 15 m s 1 along the mean convective axis of the itcz this envelope consists of many smaller scale westward moving convective elements with zonal scales on the order of 100 500 km as the convectively coupled kelvin wave disturbance propagates eastward it exerts a strong control on local convection radar and vertical profiler data collected aboard the noaa r v ronald h brown during the wave passage show that convection deepens rapidly as the kelvin wave approaches from the west progressing from isolated shallow cumuli to organized deep convective features within just 12 h initially rainfall in the vicinity of the s

a simulation study of kelvin waves interacting with synoptic events during december 2016 in the south china sea and maritime continent abstractthis study evaluates the model simulation of interaction between convectively coupled tropical disturbances in the south china sea scs and maritime contin mc the model for prediction a

evaluating the gas content of coals and isolated maceral concentrates from the paleocene guasare coalfield venezuela abstract this work presents the results from evaluating the gases sorbed by coal samples extracted from the paleocene guasare coalfield marcelina formation northwestern venezuela as well as by their distinct maceral concentrates the aim of this work has been to obtain an initial experimental main value of the gas content per unit weight of high volatile bituminous a coal samples from the open pit paso diablo mine an additional goal was to study differences in the ch 4 storage ability of the distinct maceral groups forming part of the coal matrix both the coal samples and the maceral concentrates were studied by thermogravimetric analysis tga in order to determine the temperature to be used in subsequent experiments on line analyses of hydrocarbons c 1 c 2 c 3 and co 2 yielded gas concentrations plus 13 c values thermogenic gas is prevalent in the guasare coals with vitrinite reflectance r o values from 0 65 to 0 88 the amount of gas retained in the coals and maceral concentrates was measured with a special device that allows determination of the volume of gas sorbed by a solid sample subjected to controlled thermal treatment the average coalbed gas concentration obtained was 0 51 cm 3 g the following list of maceral concentrates shows the relative capacity for the volume of sorbed gas per unit weight inertinite low density vitrinite liptinite high density vitrinite it is concluded that the gas volumes retained in the distinct maceral concentrates are not controlled by porosity but rather by their microscopic morphology

review and update of the applications of organic petrology part 1 geological applications abstract organic petrology developed as coal petrology at the beginning of the 20th century dedicated mainly to the study of coals because of their utilization in industry coal petrology was then considered a branch of coal science later with the development of specialized nomenclature classification of coal components and the standardization and improvement of analytical microscopical methods this discipline expanded in interests and name becoming organic petrology organic petrology carries a broader context being as well a tool applied in the study of dispersed organic matter in sedimentary rocks due to its importance in exploration for fossil fuel resources at present organic petrology is a discipline widely recognized for its role in fundamental and applied research with respect to both coal utilization and in geosciences throughout the 20th century several important monographs have been published on the discipline of organic petrology including stach s textbook of coal petrology 1st edition 1935 2nd 1975 3rd 1982 updated as the more general organic petrology by taylor et al 1998 more recently the text applied coal petrology the role of petrology in coal utilization was published by suarez ruiz and crelling 2008 this review is the first in a two part review series that describes and updates the role of organic petrology in geosciences a second part complementing this one and focused on the applications of organic petrology to other scientific fields will follow

low frequency modes in an equatorial shallow water model with moisture gradients motivated by observations of the mean state of tropical precipitable water pw a moist first baroclinic mode shallow water system on an equatorial plane with a background saturation profile that depends on latitude and longitude is studied in the presence of a latitudinal moisture gradient linear analysis of the non rotating problem reveals large scale symmetric eastward and westward propagating unstable modes the introduction of a zonal moisture gradient breaks the east west symmetry of the unstable modes the effects of rotation are then included by numerically solving the resulting eigenvalue problem on an equatorial plane with a purely meridional moisture gradient the system supports large scale low frequency eastward and westward moving neutral modes some of the similarities and some of the discrepancies of these modes with intraseasonal tropical waves are pointed out finally a zonal moisture gradient in the presence of rotation renders some of the aforementioned neutral modes unstable in particular according to observations of large scale low frequency tropical variability it is seen that regions where the background saturation profile increases decreases to the east favour eastward westward moving moist modes

monsoons itczs and the concept of the global monsoon earth s tropical and subtropical rainbands such as intertropical convergence zones itczs and monsoons are complex systems governed by both large scale constraints on the atmospheric general circulation and regional interactions with continents and orography and coupled to the ocean monsoons have historically been considered as regional large scale sea breeze circulations driven by land sea contrast more recently a perspective has emerged of a global monsoon a global scale solstitial mode that dominates the annual variation of tropical and subtropical precipitation this results from the seasonal variation of the global tropical atmospheric overturning and migration of the associated convergence zone regional subsystems are embedded in this global monsoon localized by surface boundary conditions parallel with this much theoretical progress has been made on the fundamental dynamics of the seasonal hadley cells and convergence zones via the use of hierarchical modeling approaches including aquaplanets here we review the theoretical progress made and explore the extent to which these advances can help synthesize theory with observations to better understand differing characteristics of regional monsoons and their responses to certain forcings after summarizing the dynamical and energetic balances that distinguish an itcz from a monsoon we show that this theoretical framework provides strong support for the migrating convergence zone picture and allows constraints on the circulation to be identified via the momentum and energy budgets limitations of current theories are discussed including the need for a better understanding of the influence of zonal asymmetries and transients on the large scale tropical circulation

origin of convectively coupled kelvin waves over south america convectively coupled kelvin waves over the south american continent are examined through the use of temporal and spatial filtering of reanalysis satellite and gridded rainfall data they are most prominent from november to april the season analyzed herein the following two types of events are isolated those that result from preexisting kelvin waves over the eastern pacific ocean propagating into the continent and those that apparently originate over amazonia forced by disturbances propagating equatorward from central and southern south america the events with precursors in the pacific are mainly upper level disturbances with almost no signal at the surface those events with precursors over south america on the other hand originate as upper level synoptic wave trains that pass over the continent and resemble the cold surges documented by garreaud and wallace as the wave train propagates over the andes it induces a southerly low level wind that advects cold air to the north precipitation associated with a cold front reaches the equator a few days later and subsequently propagates eastward with the characteristics of a kelvin wave the structures of those waves originating over the pacific are quite similar to those originating over south america as they propagate to eastern south america and into the atlantic south america kelvin waves that originate over neither the pacific nor the midlatitudes of south america can also be identified in a composite sense these form over the eastern slope of the andes mountains close to the equator there are also cases of cold surges that reach the equator yet do not form kelvin waves the interannual variability of the pacific originating events is related to sea surface temperatures in the central eastern pacific ocean when equatorial oceanic conditions are warm there tends to be an increase in the number of disturbances that reach south america from the pacific

organic geochemistry and petrology of coals and carbonaceous shales from western venezuela abstract the aim of this study is to provide geochemical and petrological data to characterize coals and carbonaceous shales from western venezuela in terms of both compositional and thermal maturity parameters the samples collected in outcrop belong to the paleocene marcelina formation the eocene oligocene carbonera formation the paleocene orocue group and the lower miocene cerro pelado formation geochemical results are based on total organic carbon toc content rock eval pyrolysis and proximate analyses whereas petrographic data include vitrinite reflectance rr and maceral composition thermal evolution of all samples is low varying from immature to early mature coals and carbonaceous shales from the marcelina and cerro pelado formations are humic the former having larger amounts of inertinite nevertheless both groups of samples are compositionally homogeneous samples from the carbonera formation and orocue group show a great compositional scatter varying from humic to sapropelic our geochemical profile for marcelina formation coals allowed the detection of the first coalification jump whereas the cerro pelado formation profile shows an abrupt decrease of organic matter content toward the top of the studied interval results shown here confirm data from previous studies relative to the high oil source rock potential of carbonera formation and orocue group coals and carbonaceous shales

convectively coupled kelvin waves in cmip5 coupled climate models this study provided a quantitative evaluation of convectively coupled kelvin waves cckws over the indian ocean and the pacific ocean simulated by 20 coupled climate models that participated in coupled model intercomparison project phase 5 the two leading empirical orthogonal function eof modes of filtered daily precipitation anomalies are used to represent the eastward propagating cckws in both observations and simulations the eigenvectors and eigenvalues of the eof modes represent the spatial patterns and intensity of cckws respectively and the lead lag relationship between the two eof principle components describe the phase propagation of cckws a non dimensional metric was designed in consideration of all the three factors i e pattern amplitude and phase propagation for evaluation the relative rankings of the models based on the skill scores calculated by the metric are conducted for the indian ocean and the pacific ocean respectively two models noresm1 m and mpi esm lr are ranked among the best 20 for both the regions three models inmcm4 mri cgcm3 and hadgem2 es are ranked among the worst 20 for both the regions while the observed cckw amplitude is greater north of the equator in the pacific some models overestimate the cckw ampliutde in the southern hemisphere this bias is related to the mean state precipitation bias along the south pacific convergence zone

structure and characteristics of submonthly scale waves along the indian ocean itcz this study examines wave disturbances on submonthly 6 30 day timescales over the tropical indian ocean during southern hemisphere summer using japanese reanalysis jra25 jcdas products and national oceanic and atmospheric administration outgoing longwave radiation data the analysis period is december february for the 29 years from 1979 1980 through 2007 2008 an extended empirical orthogonal function eeof analysis of daily 850 hpa meridional wind anomalies reveals a well organized wave train pattern as a dominant mode of variability over the tropical indian ocean daily lagged composite analyses for various atmospheric variables based on the eeof result show the structure and evolution of a wave train consisting of meridionally elongated troughs and ridges along the indian ocean intertropical convergence zone itcz the wave train is oriented in a northeast southwest direction from sumatra toward madagascar the waves have zonal wavelengths of about 3 000 5 000 km and exhibit westward and southwestward phase propagation individual troughs and ridges as part of the wave train sequentially travel westward and southwestward from the west of sumatra into madagascar meanwhile eastward and northeastward amplification of the wave train occurs associated with the successive growth of new troughs and ridges over the equatorial eastern indian ocean this could be induced by eastward and northeastward wave energy dispersion from the southwestern to eastern indian ocean along the mean monsoon westerly flow in addition the waves modulate the itcz convection correlation statistics show the average behavior of the wave disturbances over the tropical indian ocean these statistics and other diagnostic measures are used to characterize the waves obtained from the composite analysis the waves appear to be connected to the monsoon westerly flow the waves tend to propagate through a band of the large meridional gradient of absolute vorticity produced by the mean monsoon westerly flow this suggests that the monsoon westerly flow provides favorable background conditions for the propagation and maintenance of the waves and acts as a waveguide over the tropical indian ocean the horizontal structure of the wave train may be interpreted as that of a mixture of equatorial rossby waves and mixed rossby gravity wavelike gyres

source rock potential of the lowest coal seams of the marcelina formation at the paso diablo mine in the venezuelan guasare basin evidence for the correlation of amana oils with these paleocene coals abstract the aims of this work were to carry out a combined petrographic palynofacies and organic geochemical study of twelve drill core samples collected from the lowest coal seams in the paleocene marcelina formation paso diablo mine guasare basin northwestern venezuela to characterize crude oil samples from three wells in the nearby amana field and to evaluate oil source correlations of these crude oils with the paso diablo coal extracts the coals under study were classified as high volatile bituminous a or at the b a boundary and showed vitrinite contents between 50 0 and 89 4 vol liptinites ranging from 1 4 to 24 2 vol and inertinites in the 6 2 30 8 vol range results from organic geochemical investigations indicate that the guasare coals were generated in a limno telmatic to telmatic zone under fluctuating oxygen conditions a type iii kerogen with relatively high hydrogen content and a thermal maturity corresponding to the early oil window are proposed for these coals as supported by rock eval and petrographic data as well as biomarker interpretations oil generation potential from marcelina formation coals is probably due to the perhydrous nature of the vitrinite high bitumen contents and considerable liptinite concentrations mainly oil prone resinites and exsudatinites palynofacies observations denote a dominance of psilate pollen grains related to angiosperm plants and as expected type iii kerogens or humic coals in the studied seams the parent material of which contained a significant contribution of algae the non detection of 18 h oleanane does not preclude the fact that angiosperms are the dominant plants in the guasare paleomire on the other hand the characterization of the amana oils suggests that they all fall into a unique oil family the presence of 25 norhopanes in them could indicate paleobiodegradation and mixing from various hydrocarbon charges in the reservoir thus the crude oils from the amana field seem to be a mixture of one or more oil charges from the early mature marine carbonate source rocks of the la luna formation deposited under anoxic reducing conditions and a later pulse of hydrocarbon generation which originated from an unknown so far nonmarine source rock in this regard hydrocarbon liquid derived from the lowest marcelina coal seams may be tentatively identified as the latter oil charge also this work delineates some components of a currently subcommercial and hypothetical tertiary petroleum system identified and named as marcelina misoa c5 in the lake maracaibo region finally the coalbed gas contents of sampled coals were determined

mixed rossby gravity waves and western pacific tropical cyclogenesis part i synoptic evolution abstract a large amplitude mixed rossby gravity wave packet is identified in the western pacific using 6 10 day bandpass filtered winds individual disturbances of 2300 3000 km wavelength propagated westward as the packet moved slowly eastward the packet first appeared and subsequently amplified within a region of active convection associated with the madden julian oscillation mjo which was isolated by low pass filtered outgoing longwave radiation the packet lasted about 5 weeks then rapidly dispersed as the active mjo moved away from it to the east west of 150 e individual disturbances within the packet turned northwestward away from the equator indicating an apparent transition from mixed rossby gravity waves to off equatorial tropical depression td type disturbances cyclones filled with cloud and anticyclones cleared during the transition nevertheless convective structure consistent with mixed rossby gravity waves remained outside the circulation centers and three tropical cyclones for

tropical cyclogenesis within an equatorial rossby wave packet a packet of equatorial rossby er waves that lasted 2 5 months is identified in the lower troposphere of the northwest pacific waves within the packet had a period of 22 days a wavelength of 3600 km a westward phase speed of 1 9 m s 1 and a near zero group speed the wave properties followed the er wave dispersion relation with an equivalent depth near 25 m the packet was associated with the development of at least 8 of the 13 tropical cyclones that formed during the period a composite was constructed around the genesis locations tropical cyclones formed east of the center of the composite er wave low in a region of strong convection and a separate 850 hpa vorticity maximum the background flow during the life of the packet was characterized by 850 hpa zonal wind convergence and easterly vertical wind shear wave amplitude peaked at the west end of the convergent region suggesting that wave accumulation played a significant role in the growth of the packet the presence of easterly vertical wind shear provided an environment that trapped energy in the lower troposphere each of these processes increases wave amplitude and thus the likelihood of tropical cyclone formation within the waves the initial low pressure region within the wave packet met lander s definition of a monsoon gyre it developed to the west of persistent localized convection that followed the penetration of an uppertropospheric trough into the subtropics it is argued that the monsoon gyre represented the initial er wave low within the packet

analysis of convectively coupled kelvin waves in the indian ocean mjo abstract the active convective phase of the madden julian oscillation hereafter active mjo comprises enhanced moist deep convection on its own temporal and spatial scales as well as increased variance in convection associated with higher frequency modes synoptic scale cloud superclusters apparently associated with convectively coupled kelvin waves occur within the active convective envelopes of most mjo events these convectively coupled kelvin waves also occur during the suppressed convective phase of the mjo hereafter suppressed mjo this observational study presents an analysis of outgoing longwave radiation and reanalysis data to determine how these waves behave differently as they propagate through the active and suppressed mjo time indices of the mjo and kelvin waves are derived for over the equatorial indian ocean dates of local extrema in these indices are used to composite data to discern how the waves and associated circulations behave on average then further composites are made based o

a climatology of waves in the equatorial region abstract propagating anomalies of moisture and moist deep convection in the tropics are organized into a variety of large scale modes these include but are not limited to the so called intraseasonal oscillations convectively coupled waves similar to those predicted by shallow water theory on the equatorial beta plane and tropical depression type disturbances along with the annual and diurnal cycles these modes act and interact to control much of the variance of tropical convection analyses of 10 yr of outgoing longwave radiation olr and precipitable water pw data are carried out to develop comparative climatologies of these wavelike modes the analysis relaxes the commonly used cross equatorial symmetry constraints which allows study of the portions of the wavelike processes that are asymmetric across the equator mean background states are found for olr and for pw as functions of day of the year examination of anomalies together with the background reveals much about how the waves are affec

gravity anomalies of 2 d bodies with variable density contrast a new method is presented to compute gravity anomalies that result from 2 d bodies with variable density contrast the cross section of a body is approximated by a polygon density is assumed to vary as any order of polynomial function with depth and lateral position results calculated by the proposed method for models with variable density contrast compare well with other methods liaohe basin northeast china is modeled from field gravity anomalies using the formulas given showing the method is valid and effective

effects of low frequency wave interactions on intraseasonal oscillations abstract intraseasonal oscillations isos control much of the large scale variability of convection in the tropics on time scales of about 15 100 days these disturbances are often thought to be dominated by eastward propagating modes especially during austral summer but disturbances that propagate westward are also important this work demonstrates by means of a multiple linear regression model and a brief case study that eastward and westward moving intraseasonal modes often cooperatively interact with one another to produce many of the characteristics of the observed southern hemisphere summer iso these interactions appear to be facilitated by topography and or by the convective anomalies that are cooperatively induced by the eastward and the westward moving components of the oscillations these interactions do not occur during every period of intraseasonal convective activity but they do commonly occur during periods of high amplitude convective anomalies this analysis shows that eastward and

multiscale interactions in an idealized walker cell analysis with isentropic streamfunctions abstracta new approach for analyzing multiscale properties of the atmospheric flow is proposed in this study for that the recently introduced isentropic streamfunctions are employed here for scale decomposition with haar wavelets this method is applied subsequently to a cloud resolving simulation of a planetary walker cell characterized by pronounced multiscale flow the resulting set of isentropic streamfunctions obtained at the convective meso synoptic and planetary scales capture many important features of the across scale interactions within an idealized walker circulation the convective scale is associated with the shallow congestus and deep clouds which jointly dominate the upward mass flux in the lower troposphere the synoptic and planetary scales play important roles in extending mass transport to the upper troposphere where the corresponding streamfunctions mainly capture the first baroclinic mode associated with large scale overturning circulation the intermediate scale features of

the petroleum generation potential and effective oil window of humic coals related to coal composition and age abstract a worldwide data set of more than 500 humic coals from the major coal forming geological periods has been used to analyse the evolution in the remaining hydrogen index hi and total quality index qi generation potentials with increasing thermal maturity and the effective oil window oil expulsion window all samples describe hi and qi bands that are broad at low maturities and that gradually narrow with increasing maturity the oil generation potential is completely exhausted at a vitrinite reflectance of 2 0 2 2 ro or tmax of 500 510 c the initial large variation in the generation potential is related to the original depositional conditions particularly the degree of marine influence and the formation of hydrogen enriched vitrinite as suggested by increased sulphur and hydrogen contents during initial thermal maturation the hi increases to a maximum value himax similarly qi increases to a maximum value qimax this increase in hi and qi is related to the formation of an additional generation potential in the coal structure the decline in qi with further maturation is indicating onset of initial oil expulsion which precedes efficient expulsion liquid petroleum generation from humic coals is thus a complex three phase process i onset of petroleum generation ii petroleum build up in the coal and iii initial oil expulsion followed by efficient oil expulsion corresponding to the effective oil window efficient oil expulsion is indicated by a decline in the bitumen index bi when plotted against vitrinite reflectance or tmax this means that in humic coals the vitrinite reflectance or tmax values at which onset of petroleum generation occurs cannot be used to establish the start of the effective oil window the start of the effective oil window occurs within the vitrinite reflectance range 0 85 1 05 ro or tmax range 440 455 c and the oil window extends to 1 5 2 0 ro or 470 510 c for general use an effective oil window is proposed to occur from 0 85 to 1 7 ro or from 440 to 490 c specific ranges for himax and the effective oil window can be defined for cenozoic jurassic permian and carboniferous coals cenozoic coals reach the highest himax values 220 370 mg hc g toc and for the most oil prone cenozoic coals the effective oil window may possibly range from 0 65 to 2 0 ro or 430 to 510 c in contrast the most oil prone jurassic permian and carboniferous coals reach the expulsion threshold at a vitrinite reflectance of 0 85 0 9 ro or tmax of 440 445 c

a modeling study of the effect of the andes on the summertime circulation of tropical south america abstract a simple linear two level model of the atmosphere is developed which has a reasonable representation of the external and tropically important baroclinic modes by blocking the lower layer of the model with a meridional wall the interaction between diabatic forcing centered in the amazon basin and the andes is studied this forcing can be considered a source of rossby waves that scatter from the above partial barrier the scattering process is examined analytically by making the long wave approximation with the conclusion that transmission of external rossby waves reflection of baroclinic kelvin waves and the creation of topographic jets are likely to be important numerical solutions without the long wave approximation are then considered and the effects of the above scattering process are examined the upper level circulation is shown to be qualitatively similar to that obtained without a barrier the low level circulation west of the barrier is weak in the winds and consists of a positive g

the west african monsoon dynamics part iii the quasi biweekly zonal dipole abstract this paper presents an investigation of the mechanisms giving rise to the main intraseasonal mode of convection in the african monsoon during northern summer here identified as the quasi biweekly zonal dipole qbzd the qbzd is primarily characterized by a quasi stationary zonal dipole of convection whose dimension is larger than the west african monsoon domain with its two poles centered along the guinean coast and between 30 and 60 w in the equatorial atlantic the qbzd dynamical processes within the atlantic africa domain are examined in some detail the qbzd has a dipole pattern associated with a walker type circulation in the near equatorial zonal plane it is controlled both by equatorial atmospheric dynamics through a kelvin wave like disturbance propagating eastward between its two poles and by land surface processes over africa inducing combined fluctuations in surface temperatures surface pressure and low level zonal winds off the coast of west africa when convection is at a min

a multi scale analysis of the extreme rain event of ouagadougou in 2009 this study presents a multi scale analysis of an extreme rain event that occurred in burkina faso on 1st september 2009 with an absolute record of 263 mm rainfall observed at ouagadougou this high impact weather system results from the combination of several favourable ingredients at different scales the sea surface temperature anomaly patterns in july august 2009 of both the atlantic cold tongue the tropical atlantic dipole and the mediterranean sea are favourable factors for the northward penetration of the west african monsoon the intense convective activity of the last 10 day period in august is associated with the crossing of a convectively coupled kelvin wave increasing the african easterly wave aew activity and of an equatorial rossby wave at the synoptic scale this event corresponds to the passage of a train of 3 aews with increasing magnitude behind the 1st aew trough axis an intense and deep southerly monsoon burst develops it contributes to the amplification of the 2nd aew and its breaking associated with the formation of an intense meso vortex on the southern flank of the african easterly jet compared to the fast moving squall line the dominant type of precipitating weather system over the sahel the ouagadougou precipitating system appears to be a moist vortex propagating slowly allowing rainfall accumulation without wind gusts or convective cold pools observed at the surface the main precipitation area is located about 2 longitude downshear westward due to the african easterly jet of the centre of this strong meso vortex

maintenance of the intertropical convergence zones and the large scale tropical circulation on a water covered earth abstract how the surface boundary heating sea surface temperature and cumulus adjustment process affect the location structure energetics and dynamics of the intertropical convergence zones itczs is investigated a series of experiments is performed with a general circulation model where the lower boundary is specified to be water at a fixed sea surface temperature sst an aqua planet all experiments are run using equinoctal insolation with no longitudinal variation in sst two different convective parameterization schemes kuo and moist convective adjustment and several different zonally symmetric sst distributions are used in these experiments the location of the itcz is found to be sensitive to the convective parameterization scheme and the sst distribution the model with the moist convective adjustment scheme produces an itcz over the tropical sst maximum even under conditions where the sst gradient is weak by contrast the model with the kuo convective parameterization is not as sensit

a combined wave number frequency and time extended eof approach for tracking the progress of modes of large scale organized tropical convection an algorithm combining filtering in the wave number frequency domain with time extended empirical orthogonal function eeof analysis is developed and applied to diagnose and track signals associated with modes of organized moist deep convection in the tropics the wave number frequency spectrum of outgoing long wave radiation olr is broken down into five broad filter bands in order to concentrate signals associated with the madden julian oscillation convectively coupled equatorial rossby kelvin and mixed rossby gravity waves easterly waves and low frequency variations such as the el nino southern oscillation enso the eeof patterns are obtained from analysis of the filtered data and principal component pc time series are generated by projection of temporally smoothed but otherwise unfiltered data onto the eeof patterns filtered data are reconstructed by taking the product of the eeof patterns and the corresponding pcs these reconstructed data compare well with unfiltered olr anomalies and with olr anomalies filtered in the wave number frequency domain for the same modes the method is easily applied in real time since results are not influenced by the proximity to the end of the dataset copyright 2009 royal meteorological society

modulation of the convectively coupled kelvin waves over south america and the tropical atlantic ocean in association with the madden julian oscillation abstractin this study evidence of the strong modulation of the convectively coupled kelvin wave cckw activity by the madden julian oscillation mjo is presented with a particular focus over the south america and tropical atlantic region the mjo impacts on cckws over this region as noted in anomalous fields of rainfall as well as vertical profiles of wind moisture and temperature are primarily through the modulation of kelvin wave amplitude with secondary effects on vertical structure and little impact on wavenumber cckw activity is enhanced during mjo phases 8 1 and 2 and damped during mjo phases 4 5 and 6 further analyses reveal that the strong modulation of the mjo on the cckw activity could be largely through two factors namely the vertical zonal wind shear and the lower to middle tropospheric specific humidity the cckw activity tends to be enhanced during mjo phases when the easterly vertical wind shear and positive low to midtroposphere moisture anomalies are present and vice ve

extratropical forcing of convectively coupled kelvin waves during austral winter abstract observations are presented that link extratropical rossby wave disturbances excited in the southern hemisphere subtropical jet to the initiation of convectively coupled kelvin waves in the pacific intertropical convergence zone itcz during austral winter a baroclinic zonal wavenumber 6 eastward propagating rossby wave train in the subtropical jet turns northeastward in the vicinity of australia inducing upper tropospheric divergence and vertical motion fields that spread equatorward and induce cloudiness anomalies in the tropics lower tropospheric pressure surges excited from the extratropics also induce kelvin wave like geopotential height and temperature anomalies at the surface providing additional lower tropospheric convergence and vertical motion forcing the tropical outgoing longwave radiation olr and circulation fields propagate eastward in tandem with the extratropical rossby wave train at approximately 17 m s 1 kelvin wave activity in the central pacific itcz thus appears to

equatorial atmospheric waves and their association to convection equatorial wave systems and their relationships with convective activity are analyzed in the western and central pacific regions during the coupled ocean atmosphere response experiment coare intensive observation periods the study uses geostationary meteorological satellite infrared temperature observations and the operational european centre for medium range weather forecasts analyses supplemented with coare observations spectral and complex principal component analysis are applied to the data using the linear theory of equatorially trapped waves as a guideline the existence of three types of waves is detected in the 7 10 day period range n 5 1 rossby waves are found to the east of the date line in a region of weak convective activity over the western equatorial pacific where intense convection occurs the 7 10 day waves do not possess the general characteristics of linear rossby waves but they are strongly linked to the active phases of westerly wind bursts and of convection analysis of the meridional wind reveals intense mixed rossby gravity waves with a mean 5 day period and westward phase and eastward group velocities over the western pacific the convection is found to be strongly correlated with the antisymmetric structure of the divergent field as predicted by the linear theory in the 200 hpa divergence field n 5 1 gravity waves are visible having periods shorter than 2 5 days they rapidly propagate about 25 m s21 both westward and eastward and have strong correlations with convective clusters

multi scale interactions of equatorial waves associated with tropical cyclogenesis over the western north pacific the tropical cyclone tc centric approach developed in previous studies tends to overemphasize the direct impact of tropical waves and underestimates their large scale modulation of western north pacific wnp tropical cyclogenesis tcg to overcome these limitations this study proposes a new approach based on empirical orthogonal function analyses to re examine associations of multiple waves including the madden julian oscillation mjo quasi biweekly oscillation qbwo convective equatorial rossby er waves and synoptic scale waves ssws with wnp tcg events there is a close association between wnp tcg events total of 273 tcs in this study and ssws 64 mjo 68 qbwo 64 and er 65 waves these suggest that ssw is critical for many tcg events and all of these intra seasonal waves significantly modulate tcg events a majority of tcs 79 were found to be related to more than one wave type indicating an important role for a combination of dynamic and thermodynamic conditions associated with multiple waves in tcg events further analyses show that ssw activity is strongly modulated by the mjo and er waves while the qbwo has no significant impact on ssws during convectively active mjo and er phases stronger ssw trains with more distinct southeast northwestward aligned structures can be found compared to convectively inactive phases similar intra seasonal modulation of the transition from the mixed rossby gravity waves from the equatorial central pacific to the ssw trains over the wnp by the three waves is noted with such transitions largely favored during convectively active mjo and er phases

adapting palynological preparation methods in subbituminous and bituminous coals from colombia to improve palynofacies and hydrocarbon source rock evaluations abstract apart from their potential as fossil fuel bituminous and subbituminous coals in colombia may prove to be potential source rocks for the generation of hydrocarbons the assessment of such properties requires the combination of petrographic and palynofacies studies the latter correspond to the microscopic investigation in transmitted white and reflected uv lights of sedimentary organic matter insoluble in organic and inorganic solvents to date mineral acid and schulze methods have failed to produce good samples of palynofacies constituents from cenozoic coals in colombia so that the latter method had to be modified the main modifications consist in adapting the kclo 3 to hno 3 ratio in the schulze mixture and introducing two extra phases of oxidation with naoh and nh 4 oh which permit the washing off of humic substances this method yields the full spectrum of palynofacies constituents which are not destroyed or damaged by the alkali treatment neither is their fluorescence colour affected by the initial acid treatment on the contrary the particle fluorescence intensity tends to increase because of the dissolution of humic acids making their identification easier the achievements of the modified method are threefold 1 it permits the correlation between macerals in petrographic polished sections and their equivalent in palynofacies slides making the two methods complementary 2 palynofacies provides a better identification of sporomorphs than petrography resulting in better paleoenvironmental interpretations 3 palynofacies tend to give a more precise quantitative evaluation of the liptinitic constituents and consequently of the coal hydrocarbon generation potential

simulation and interpretation of the genesis of tropical storm gert 2005 as part of the nasa tropical cloud systems and processes experiment abstract several hypotheses have been put forward for the mechanisms of generation of surface circulation associated with tropical cyclones this paper examines high resolution simulations of tropical storm gert 2005 which formed in the gulf of mexico during nasa s tropical cloud systems and processes experiment to investigate the development of low level circulation and its relationship to the precipitation evolution two simulations are examined one that better matches available observations but underpredicts the storm s minimum sea level pressure and a second one that somewhat overintensifies the storm but provides a set of simulations that encapsulates the overall genesis and development characteristics of the observed storm the roles of convective and stratiform precipitation processes within the mesoscale precipitation systems that formed gert are discussed during 21 25 july two episodes of convective system development occurred in each precipitation system evolution was characterized by i

assessment of hydrocarbon source rock potential of polish bituminous coals and carbonaceous shales abstract we analyzed 40 coal samples and 45 carbonaceous shale samples of varying thermal maturity vitrinite reflectance 0 59 to 4 28 from the upper carboniferous coal bearing strata of the upper silesian lower silesian and lublin basins poland to evaluate their potential for generation and expulsion of gaseous and liquid hydrocarbons we evaluated source rock potential based on rock eval pyrolysis yield elemental composition atomic h c and o c and solvent extraction yields of bitumen an attempt was made to relate maceral composition to these source rock parameters and to composition of the organic matter and likely biological precursors a few carbonaceous shale samples contain sufficient generation potential pyrolysis assay and elemental composition to be considered potential source rocks although the extractable hydrocarbon and bitumen yields are lower than those reported in previous studies for effective type iii source rocks most samples analysed contain insufficient capacity for generation of hydrocarbons to reach thresholds required for expulsion primary migration to occur in view of these findings it is improbable that any of the coals or carbonaceous shales at the sites sampled in our study would be capable of expelling commercial amounts of oil inasmuch as a few samples contained sufficient generation capacity to be considered potential source rocks it is possible that some locations or stratigraphic zones within the coals and shales could have favourable potential but could not be clearly delimited with the number of samples analysed in our study because of their high heteroatomic content and high amount of asphaltenes the bitumens contained in the coals are less capable of generating hydrocarbons even under optimal thermal conditions than their counterpart bitumens in the shales which have a lower heteroatomic content

interpreting rock eval pyrolysis data using graphs of pyrolizable hydrocarbons vs total organic carbon kerogen the major organic component of sedimentary rocks is commonly analyzed by rock eval pyrolysis plotting the data on a graph of s 2 vs total organic carbon toc and determining the regression equation is the best method for determining the true average hydrogen index and measuring the adsorption of hydrocarbon by the rock matrix such a plot also indicates the type of kerogen present and avoids the problem of increasing hydrogen index with total organic carbon content with the s 2 vs toc diagram the organic component of different suites of samples may be compared and their petroleum generation potentials established as an example the diagrams are used to evaluate the sedimentary environments and petroleum potential of the paleogene evaporitic sediments of the mulhouse basin alsace france

the influence of amazon rainfall on the atlantic itcz through convectively coupled kelvin waves abstract using outgoing longwave radiation olr and tropical rainfall measuring mission trmm daily rain rate data systematic changes in intensity and location of the atlantic intertropical convergence zone itcz were detected along the equator during boreal spring it is found that the changes in convection over the tropical atlantic may be induced by deep convection in equatorial south america lagged regression analyses demonstrate that the anomalies of convection developed over the land propagate eastward across the atlantic and then into africa the eastward propagating disturbances appear to be convectively coupled kelvin waves with a period of 6 7 5 days and a phase speed of around 15 m s 1 these waves modulate the intensity and location of the convection in the tropical atlantic and result in a zonal variation of the atlantic itcz on synoptic time scales the convectively coupled kelvin wave has substantial signals in both the lower and upper troposphere both a reanalysis dataset and the qui

the changing course of the orinoco river during the neogene a review abstract recent studies have revealed that the rich fresh water vertebrate fossil fauna of the urumaco formation in northwestern falcon of late miocene age belongs biogeographically to the orinoco river system this finding together with other evidence can be used to chart the changing course of the orinoco river during the neogene and thus date the uplift of various mountain ranges that affected the change in this course presence of the misoa delta in the middle eocene of the maracaibo basin has been suggested as evidence for a large river running in a south north direction and draining the central cordillera of colombia and the guayana highlands the late middle eocene uplifting of western venezuela changed the paleogeographic setting and a new delta building shifted to the south represented by the extensive carbonera formation of late eocene to oligocene age in the llanos basin of colombia and southwestern venezuela in the earliest miocene the falcon basin situated to the east of the maracaibo basin was primarily the site of marine shale sedimentation stratigraphic and microfaunal evidence suggests the possibility of the presence of the proto orinoco river in the western margin of the basin in any case from the mid early miocene until the end of the middle miocene a fluvio deltaic sequence was deposited in the northwestern falcon with a total thickness of 4 7 km the urumaco formation overlies this sequence and its vertebrate fauna indicates that the river which built the prior delta was definitely the proto orinoco the deformation and uplift of the eastern cordillera of colombia and of the southwestern end of the merida andes caused the distal course of the river to be deflected to a west east direction a late middle miocene age for this change of course is precisely dated on marine microfaunal evidence the late miocene sedimentary record of the orinoco river delta appears east of maturin in the eastern venezuela basin and pliocene and pleistocene deltaic sediments are especially evident in trinidad and the columbus basin

petrology mineralogy and geochemistry of mined coals western venezuela upper paleocene to middle miocene coal samples collected from active mines in the western venezuelan states of tachira merida and zulia have been characterized through an integrated geochemical mineralogical and petrographic investigation proximate ultimate calorific and forms of sulfur values major and trace element vitrinite reflectance maceral concentrations and mineral matter content have been determined for 16 channel samples from 14 mines ash yield generally is low ranging from b 1 to 17 wt mean 5 wt on a dry basis db total sulfur content is low to moderate ranging from 1 to 6 wt db average 1 7 wt calorific value ranges from 25 21 to 37 21 mj kg 10 840 16 000 btu lb on a moist mineral matter free basis average 33 25 mj kg 14 300 btu lb placing most of the coal samples in the apparent rank classification of high volatile bituminous most of the coal samples exhibit favorable characteristics on the various indices developed to predict combustion and coking behavior and concentrations of possible environmentally sensitive elements as be cd cr co hg mn ni pb sb se th and u generally are similar to the concentrations of these elements in most coals of the world with one or two exceptions concentrations of the liptinite maceral group range from b 1 to 70 vol five samples contain n 20 vol liptinite dominated by the macerals bituminite and sporinite collotelinite dominates the vitrinite group telinite was observed in quantities of v1 vol despite efforts to better quantify this maceral by etching the sample pellets in potassium permanganate and also by exposure in an oxygen plasma chamber inertinite group macerals typically represent b 10 vol of the coal samples and the highest concentrations of inertinite macerals are found in distantly spaced n 400 km upper paleocene coal samples from opposite sides of lago de maracaibo possibly indicating tectonic controls on subsidence related to construction of the andean orogen values of maximum reflectance of vitrinite in oil ro max range between 0 42 and 0 85 and generally are consistent with the high volatile bituminous rank classification obtained through astm methods x ray diffraction analyses of low temperature ash residues indicate that kaolinite quartz illite and pyrite dominate the inorganic fraction of most samples plagioclase potassium feldspar calcite siderite ankerite marcasite rutile anatase and apatite are present in minor or trace concentrations semiquantitative values of volume percent pyrite content show a strong correlation with pyritic sulfur and some sulfide hosted trace element concentrations as and hg this work provides a modern quality dataset for the western

geochemistry of oil seeps and rock samples of the early tertiary section from the northandean flank of the venezuelan andes abstract an organic geochemical study of oil seeps and early to middle tertiary source rocks of the northandean flank naf of the venezuelan andes range was performed to establish the possible contribution of terrestrial source rocks to the oil accumulations in the unexplored southern part of the maracaibo basin source rocks were identified within the paleocene barco and los cuervos formations and the late eocene oligocene carbonera formation biomarker distributions indicate a terrigenous organic source for these units geochemical modeling performed by parnaud et al 1995 indicated plio pleistocene oil generation for the orocue group and middle miocene to plio pleistocene oil generation for the carbonera formation geochemical modeling also indicates that the quantity of crude oil expelled by the carbonera formation is four times that expelled by the orocue group barco and los cuervos formations a northeast to southwest variation from marine to terrestrial oil seeps was identified based on sterane and terpane distributions the marine oil seeps appear to be derived from the la luna source rocks the characteristics of the mixed oils suggest contributions from different sources la luna and a terrestrial source rock most likely the orocue group or carbonera formation coals source facies similar to those in the los cuervos and carbonera formations coals are most likely the main source rocks of terrestrial oil seeps in the naf

eastward propagating 2 to 15 day equatorial convection and its relation to the tropical intraseasonal oscillation anomalies of outgoing longwave radiation olr in 1980 1989 were examined in a narrow latitude band about the equator to elucidate the propagation and interaction of tropical intraseasonal oscillations tios and synoptic scale convective activity hovmoller diagrams of olr data reconstructed from two frequency bands corresponding to periods of 30 60 days and 2 15 days respectively revealed a clear distinction between the phase speed of eastward moving tios 3 7 m s 1 and that of eastward synoptic scale convection 10 13 m s 1 coherent propagation of tios from the indian to the western pacific oceans was often observed with temporary diminution of amplitude over the maritime continent propagation of high frequency anomalies was generally confined to an individual basin dominance of eastward propagating synoptic scale convection in the equatorial zone contrasts sharply with the westward propagation of off equatorial convergence zones interaction between the tio and high frequency activity resolved by daily olr was visible as a modest enhancement of eastward synoptic scale events and of high frequency activity in general during the convectively active phase of the tio

convectively coupled kelvin waves from linear theory to global models abstractthe authors analyze composite structures of tropical convectively coupled kelvin waves cckws in terms of the theory of raymond and fuchs using radiosonde data 3d analysis and reanalysis model output and annual integrations with the ecmwf model on the full planet and on an aquaplanet precipitation anomalies are estimated using the noaa interpolated olr and trmm 3b42 datasets as well as using model olr and rainfall diagnostics derived variables from these datasets are used to examine assumptions of the theory large scale characteristics of wave phenomena are robust in all datasets and models where kelvin wave variance is large indices from the theory representing column moisture and convective inhibition are also robust the results suggest that the cckw is highly dependent on convective inhibition while column moisture does not play an important role

the spectrum of convectively coupled kelvin waves and the madden julian oscillation in regions of low level easterly and westerly background flow abstractthe zonal wavenumber frequency power spectrum of outgoing longwave radiation in the global tropics suggests that power in convectively coupled kelvin waves and the madden julian oscillation mjo is organized into two distinct spectral peaks with a minimum in power in between this work demonstrates that integration of wavelet power in the wavenumber frequency domain over geographical regions of moderate trade winds yields a similar pronounced spectral gap between these peaks in contrast integration over regions of background low level westerly wind yields a continuum of power with no gap between the mjo and kelvin bands results further show that signals in tropical convection are redder in frequency in these low level westerly wind zones confirming that kelvin waves tend to propagate more slowly eastward over the warm pool than other parts of the world results are consistent with the perspective that portions of disturbances labeled as kelvin waves and the mjo that are proximate to kelvin wa

role of multiple equatorial waves on cyclogenesis over bay of bengal tropical variations on intraseasonal time scales like madden julian oscillations mjo tropical depressions and convectively coupled equatorial waves ccews are known to modulate the probability of cyclogenesis over different ocean basins in the present study a detailed analysis of the role of mjo kelvin waves equatorial rossby er waves and combined mixed rossby gravity waves and tropical depressions mt on cyclogenesis over the bay of bengal bob is carried out for a period of 1979 2013 the effect of different waves occurring individually and their combinations on the cyclogenesis over bob is studied it is shown that the cyclogenesis is favoured over bob when multiple waves are present simultaneously than in the presence of a single wave individually er is most favourable for the cyclogenesis followed by mjo while mt is the least favourable a combination of er and mjo is associated with the highest number of cyclogenesis and the least number of cyclones are formed when kelvin and mt are present together modulation of the atmospheric factors contributing to the cyclogenesis potential namely vorticity relative humidity rh and vertical wind shear by different waves is discussed it is shown that the mjo increases the cyclogenesis by increasing rh while the rossby wave contributes by increasing the relative vorticity and mt contributes by reducing the vertical wind shear on the other hand mt has the least rh while kelvin wave is associated with the least vorticity thus contributing to lesser number of cyclogenesis

the role of tropical waves in tropical cyclogenesis abstract this paper analyzes relationships between tropical wave activity and tropical cyclogenesis in all of the earth s major tropical cyclone basins twenty nine years of outgoing longwave radiation data and global reanalysis winds are filtered and analyzed to determine statistical relationships between wave activity in each basin and the corresponding cyclogenesis composite analyses relative to the storm genesis locations show the structures of the waves and their preferred phase relationships with genesis five wave types are examined in this study including mixed rossby gravity waves tropical depression type or easterly waves equatorial rossby waves kelvin waves and the madden julian oscillation the latter is not one of the classical tropical wave types but is a wavelike phenomenon known to have a strong impact on tropical cyclogenesis tropical cyclone formation is strongly related to enhanced activity in all of the wave filter bands except for the kelvin band in each basin the structure o

projection of tropical cyclones on wavenumber frequency filtered equatorial waves theimpactoflocalizedconvectionassociatedwithtropicalcyclones tcs onactivityascribedtoequatorial waves is estimated an algorithm is used to remove outgoing longwave radiation olr signal in the vicinity of observed tropical cyclones and equatorial wave modes are extracted using the standard wavenumber frequency decomposition method the results suggest that climatological activity of convection coupled equatorial waves is overestimated where tc tracks are densest the greatest impact is found for equatorial rossby er and tropical depression td type waves followed by the madden julian oscillation mjo the basins most affected are the eastern and western north pacific ocean where on average tcs may contribute up to 10 15 of the climatological wave amplitude variance in these modes in contrast kelvin waves are least impacted by the projection of tcs the results are likely relevant for studies on the climatology of equatorial waves in observations and global climate model simulations and for those examining individual cases of tc genesis modulated by equatorial wave activity