comment on temporal and spatial precursors in ionospheric total electron content of the 16 october 1999 mw 7 1 hector mine earthquake by su et al 2013 we review the recent paper by su et al 2013 using global position system and global ionospheric maps data su et al claimed to have found ionospheric precursors a few days before the 16 october 1999 hector mine california earthquake they proposed that this type of analysis of ionospheric data may be useful for locating forthcoming large earthquakes in this comment we reexamine these data and show that ionospheric anomalies reported by su et al were not precursors to the hector mine earthquake therefore their proposed analysis is not useful in the context of earthquake prediction

kinematic and precipitation characteristics of convective systems observed by airborne doppler radar during the life cycle of a madden julian oscillation in the indian ocean abstractthis study presents characteristics of convective systems observed during the dynamics of the madden julian oscillation dynamo experiment by the instrumented noaa wp 3d aircraft nine separate missions with a focus on observing mesoscale convective systems mcss were executed to obtain data in the active and inactive phase of a madden julian oscillation mjo in the indian ocean doppler radar and in situ thermodynamic data are used to contrast the convective system characteristics during the evolution of the mjo isolated convection was prominent during the inactive phases of the mjo with deepening convection during the onset of the mjo during the mjo peak convection and stratiform precipitation became more widespread a larger population of deep convective elements led to a larger area of stratiform precipitation as the mjo decayed convective system top heights increased though the number of convective systems decreased eventually transitioning back to isolated convection a distinct

the transition zone and secondary maximum of radar reflectivity behind a midlatitude squall line results retrieved from doppler radar data abstract thermodynamic and microphysical retrieval techniques are applied to dual doppler synthesized air motion fields for a midlatitude squall line which passed through the oklahoma kansas preliminary regional experiment for the stormscale operational and research meteorology program pre storm observational array in kansas and oklahoma on 10 11 june 1985 the retrieved pressure and potential temperature fields are consistent with surface network and sounding data while the retrieved microphysical fields show the characteristic secondary maximum of radar reflectivity in the stratiform region and the band of low reflectivity or transition zone lying between the leading convective line and the secondary maximum the retrieved fields indicate the processes producing the secondary maximum and transition zone minimum of radar reflectivity more quantitatively than has been possible in previous studies the primary processes accounting for these features of the radar reflectivity pattern were 1 the subst

zonal and vertical structure of the madden julian oscillation abstract a statistical study of the three dimensional structure of the madden julian oscillation mjo is carried out by projecting dynamical fields from reanalysis and radiosonde data onto space time filtered outgoing longwave radiation olr data mjo convection is generally preceded by low level convergence and upward motion in the lower troposphere while subsidence cooling and drying prevail aloft this leads to moistening of the boundary layer and the development of shallow convection followed by a gradual and then more rapid lofting of moisture into the middle troposphere at the onset of deep convection after the passage of the heaviest rainfall a westerly wind burst region is accompanied by stratiform precipitation where lower tropospheric subsidence and drying coincide with continuing upper tropospheric upward motion the evolution of the heating field leads to a temperature structure that favors the growth of the mjo the analysis also reveals distinct differences in the vertical structure

the precipitating cloud population of the madden julian oscillation over the indian and west pacific oceans 1 the variability of the precipitating cloud population of the madden julian oscillation mjo is represented by statistics of echo features seen by the tropical rainfall measuring mission s precipitation radar over the central indian and west pacific oceans echo features include isolated shallow echoes deep convective cores wide convective cores and broad stratiform regions isolated shallow echoes are ever present but most numerous during suppressed mjo phases broad stratiform regions dominate variability in areal coverage and maximize during active phases deep convective and wide convective cores are more common and variable in number than broad stratiform regions the magnitude of variability is similar in both regions in the central indian ocean active mjo phases have synchronous maximization of deep convective entities in the west pacific broad stratiform regions maximize prior to wide convective cores reanalysis indicates that isolated shallow echoes are most numerous in dry mid tropospheric conditions and strong low level 1000 750 hpa shear mid tropospheric moisture increases before deeper convective features increase in number maximizes as deep convective features maximize and decreases as wide convective cores and broad stratiform regions decline in population active stage deep and wide convective cores occur preferentially with moist mid tropospheric conditions and strong low level shear acute shear may favor downdraft momentum transport and consequently more robust gust front convective triggering broad stratiform regions maximize with a moist mid troposphere strong low level shear and moderate upper level 750 500 hpa shear that is not so strong that the stratiform region disconnects from its convective moisture source

diurnally modulated cumulus moistening in the preonset stage of the madden julian oscillation during dynamo abstractatmospheric soundings radar and air sea flux measurements collected during dynamics of the madden julian oscillation dynamo are employed to study mjo convective onset i e the transition from shallow to deep convection in the tropical indian ocean the findings indicate that moistening of the low midtroposphere during the preonset stage of the mjo is achieved by simultaneous changes in the convective cloud population and large scale circulation namely cumuliform clouds deepen and grow in areal coverage as the drying by large scale subsidence and horizontal westerly advection wane the reduction of large scale subsidence is tied to the reduction of column radiative cooling during the preonset stage which ultimately links back to the evolving cloud population while net column moistening in the preonset stage is tied to large scale circulation changes a new finding of this study is the high degree to which the locally driven diurnal cycle invigorates convective clouds and cumulus moiste

the vertical structure of toga coare convection part i radar echo distributions radar data collected by the 5 cm mit radar which was deployed aboard the r v vickers during the intensive observing period of the tropical ocean global atmosphere coupled ocean atmosphere response experiment are partitioned into convective and stratiform cartesian grid columns the vertical structure of convective echo is examined through the use of two variables echo top height and the height of the 30 dbz reflectivity contour the first of these variables has traditionally been used to describe the vertical structure characteristics of convection and the second has recently been linked to internal microphysical properties and lightning histograms of the relative frequency of convective only echo top heights and 30 dbz contour heights were constructed for the three cruises of the vickers with each cruise experiencing different phases of the intraseasonal oscillation iso cruise 1 which was dominated by the convectively inactive phase of the iso was characterized by the highest frequency of shallow convection based on echo top heights whereas cruise 2 which was dominated by a particularly well defined passage of the convective phase of the iso exhibited the tallest echo top heights cruise 3 convection was influenced by moderate westerly surface winds characteristic of postwesterly wind burst conditions and convection was of intermediate height when viewed as a function of internal vertical structure i e 30 db z contour height the frequency distributions vary less from cruise to cruise with cruises 1 and 2 having nearly identical distributions of convective 30 dbz contour heights furthermore when the contribution to convective rainfall is examined as a function of 30 dbz contour height it is seen that relatively more rain fell from vertically intense convection i e convection with tall 30 dbz contours during cruises 1 and 3 than during cruise 2 instantaneous correlations between rainfall rate and radar echo height were highly scattered about a mean value of about 0 55 whereas rainfall rate and 30 dbz contour height correlations peaked at about 0 8 and exhibited much less scatter

climate and biomes in the west mediterranean area during the pliocene a new pollen derived method of climatic quantification based on the mutual climatic range of plant taxa has been applied to 17 pliocene pollen sequences in the west mediterranean area the latitudinal gradient observed in the pollen data was confirmed by the climatic reconstructions there is a gradient from north to south both for temperatures and precipitation at the beginning of the pliocene 5 32 5 ma the climate in the north mediterranean area was on average warmer and more humid than today respectively 1 4oc and 400 700 mm in the south mediterranean region the climate was both warmer and drier than today respectively equal to or 5oc higher and drier or equal humidity the pollen based climate estimates were then used to reconstruct biomes for the region the results show the occurrence of three biomes the broad leaved evergreen warm mixed forest the xerophytic woods scrub biome and the warm grass shrub biome these biomes are still represented today in the mediterranean region despite different thermic and water conditions

precipitation hydrometeor type relative to the mesoscale airflow in mature oceanic deep convection of the madden julian oscillation composite analysis of mature near equatorial oceanic mesoscale convective systems mcss during the active stage of the madden julian oscillation mjo shows where different hydrometeor types occur relative to convective updraft and stratiform midlevel inflow layers the national center for atmospheric research ncar s polka radar observed these mcss during the dynamics of the madden julian oscillation atmospheric radiation measurement mjo investigation experiment dynamo amie ncar s particle identification algorithm pid is applied to s polka s polarimetric data to identify the dominant hydrometeor type in each radar sample volume combining s polka s doppler velocity data with the pid demonstrates that hydrometeors have a systematic relationship to the airflow within mature mcss in the convective region moderate rain occurs within the updraft core the heaviest rain occurs just downwind of the core wet aggregates occur immediately below the melting layer narrow zones containing graupel rimed aggregates occur just downstream of the updraft core at midlevels dry aggregates dominate above the melting level and smaller ice particles occur along the edges of the convective zone in the stratiform region rain intensity decreases toward the anvil melting aggregates occur in horizontally extensive but vertically thin regions at the melting layer intermittent pockets of graupel rimed aggregates occur atop the melting layer dry aggregates and small ice particles occur sequentially above the melting level and horizontally oriented ice crystals occur between 10 c and 20 c in turbulent air above the descending midlevel inflow suggesting enhanced depositional growth of dendrites the organization of hydrometeors within the midlevel inflow layer is insensitive to the presence or absence of a leading convective line

kinematics and microphysics of the transition zone of the 10 11 june 1985 squall line abstract a high resolution composite analysis covering the entire breadth of the northern portion of a mature leading line trailing stratiform squall line system reveals that mean subsidence observed in the transition zone consisted of two different types of average downdraft one at upper levels that was mechanically forced and one at lower levels that was microphysically forced both the upper level and lower level mean downdrafts in the transition zone appeared to be the average effect of convective scale vertical drafts associated with convective structures that moved relative to the front edge of the convective line the structure of individual upper level convective scale downdrafts suggested that they may have been partially composed of gravity waves excited by the interaction of the penetrative convective updrafts of the mature and dissipating convective cells with the stable ambient flow the lower level mean downdraft extended from midlevels to near the surface but was maximum near the melting

the vertical structure of toga coare convection part ii modulating influences and implications for diabatic heating abstract the temporal variability of western pacific warm pool convection especially its vertical structure is examined in this study distributions of convective echo top heights and 30 dbz contour heights have been produced from shipboard radar data collected during tropical ocean global atmosphere coupled ocean atmosphere response experiment toga coare elevation and suppression of convective heights was primarily influenced by the phase of the intraseasonal oscillation iso with heights being suppressed during convectively inactive and westerly wind burst wwb phases of the iso echo top heights were greatest during the convective phases and post wwb phases of the iso however at least some very deep convection was always present within the area observed by radar indicating that local conditions were favorable for deep convection even when the large scale environment was not capable of supporting widespread deep convection in addition to the iso echo top and 30 dbz contour heights were als

late miocene to early pliocene sedimentary environments and climatic changes in the alpine carpathian pannonian junction area a case study from the danube basin northern margin slovakia abstract the danube basin situated at the alpine carpathian pannonian junction represents a region of the central paratethys strongly influenced by orogen building processes and climatic changes the geodynamic development mirrors gentle docking of the carpathians into the european platform margin associated with synrift and later postrift subsidence of the back arc area onset of the basin inversion characterized the pliocene evolution the aquatic environments gradually changed from marine brackish to caspibrackish and to freshwater within the lake pannon due to isolation followed by development of ephemeral lakes and alluvial plains the terrestrial record documents the extinction of the middle miocene fauna and the retreat of vegetation with subtropical floral elements at the beginning of the late miocene due to changes in paleogeography and climate between 11 5 and 7 1 ma the immigration of a new hipparion fauna as well as the replacement of swamp vegetation by coniferous forest of the temperate zone can be interpreted as the first appearance of seasonality with lowered humidity at the pannonian pontian boundary the late pontian to early pliocene fauna and flora as well as sedimentary environments support the increase of humidity in warm temperate climate between 7 1 and 5 4 ma

palynological evidence for miocene climate change in the forecarpathian basin central paratethys nw bulgaria abstract we reconstruct quantitatively the middle to upper miocene climate evolution in the southern forecarpathian basin central paratethys area northwest bulgaria by applying the coexistence approach to 101 well dated palynofloras isolated from three cores the climatic evolution is compared with changes in vegetation and palaeogeography the middle miocene was a period of a subtropical warm temperate humid climate with mean annual temperature mat between 16 and 18 c and mean annual precipitation map between 1100 and 1300 mm thereby during the entire middle miocene a trend of slightly decreasing temperatures is observed and only small climate fluctuations occur which are presumably related to palaeogeographic reorganisations the vegetation shows a corresponding trend with a decrease in abundance of palaeotropic and thermophilous elements the upper miocene is characterised by more diverse climatic conditions probably depending on palaeogeographic and global climatic transformations the beginning of this period is marked by a slight cooling and a significant drying of the climate with mat 13 3 17 c and map 652 759 mm after that fluctuations of all palaeoclimate parameters occur displaying cycles of humid dryer and warmer cooler conditions which are again well reflected in the vegetation our study provides a first quantitative model of the middle upper miocene palaeoclimate evolution in southeastern europe and is characterised by a relatively high precision and resolution with respect to the climate data and stratigraphy

systematic variation of drop size and radar rainfall relations time histories of the characteristics of the drop size distribution of surface disdrometer measurements collected at kapingamarangi atoll were partitioned for several storms using rain rate r reflectivity factor z and median diameter of the distribution of water content d0 this partitioning produced physically based systematic variations of the drop size distribution dsd and z r relations in accord with the precipitation types viewed simultaneously by a collocated radar wind profiler these variations encompass the complete range of scatter around the mean z r relations previously reported by tokay and short 1996 for convective and stratiform rain and demonstrate that the scatter is not random the systematic time or space variations are also consistent with the structure of mesoscale convective complexes with a sequence of convective transition and stratiform rain described by various authors there is a distinct inverse relation between the coefficient a and the exponent of the z r relations which has been obscured in prior work because of the lack of proper discrimination of the rain types contrary to previous practice it is evident that there is also a distinct difference in the dsd and the z r relations between the initial convective and the trailing transition zones the previously reported z r relation for convective rain is primarily representative of the transition rain that was included in the convective class the failure of present algorithms to distinguish between the initial convective and the trailing transition rains causes an erroneous apportionment of the diabatic heating and cooling and defeats the primary intent of discriminating stratiform from convective rains

tertiary palaeogeography and tectonostratigraphic evolution of the northern and southern peri tethys platforms and the intermediate domains of the african eurasian convergent plate boundary zone abstract the increasing effects of african eurasian convergence during the tertiary resulted in the uplift and emergence of the northern and southern peri tethys platforms palaeogeographic maps covering six selected time slices including the middle eocene late early oligocene late early miocene early middle miocene early late miocene and middle to late pliocene illustrate that environmental and depositional differentiations on the northern platform and along the bordering domains of the convergence zone were more pronounced than on the southern platform and its adjacent areas the tectonic evolution of the northern platform included an overall eastward directed trend in the onset of basin uplift and emergence which started at about the eocene oligocene transition at 34 ma tectonostratigraphic analyses indicate a striking contemporaneity of the events which defined the temporal and spatial development of both the domains of the convergent plate boundary zone and the bordering platforms five episodes of major regional change in palaeogeographic and tectonic setting are distinguished they occurred in the late eocene 37 34 ma early late oligocene 30 27 ma latest early to earliest middle miocene 17 15 ma early late miocene 9 8 ma and late early to early middle pliocene 4 3 ma these episodes encompassed changes which were most probably induced by geodynamic events primarily related to the relative motions of the african arabian and eurasian plates in turn the plate motions are assumed to have triggered discrete steps in the regional kinematics and geodynamics that governed the palaeogeographic evolution of the peri tethys platforms and the intermediate domains of the african eurasian plate boundary zone

the role of environmental shear and thermodynamic conditions in determining the structure and evolution of mesoscale convective systems during toga coare abstract a collection of case studies is used to elucidate the influence of environmental soundings on the structure and evolution of the convection in the mesoscale convective systems sampled by the turboprop aircraft in the tropical ocean global atmosphere toga coupled ocean atmosphere response experiment coare the soundings were constructed primarily from aircraft data below 5 6 km and primarily from radiosonde data at higher altitudes the well documented role of the vertical shear of the horizontal wind in determining the mesoscale structure of tropical convection is confirmed and extended as noted by earlier investigators nearly all convective bands occurring in environments with appreciable shear below a low level wind maximum are oriented nearly normal to the shear beneath the wind maximum and propagate in the direction of the low level shear at a speed close to the wind maximum when there is appreciable shear at middle levels 800 400 mb convective bands form parallel to the shear with

convective characteristics of the madden julian oscillation over the central indian ocean observed by shipborne radar during dynamo abstractthis study investigates the convective population and environmental conditions during three mjo events over the central indian ocean in late 2011 using measurements collected from the research vessel r v roger revelle deployed in dynamics of the mjo dynamo radar based rainfall estimates from the revelle c band radar are first placed in the context of larger scale tropical rainfall measuring mission trmm rainfall data to demonstrate that the reduced revelle radar range captured the mjo convective evolution time series analysis and mjo phase based composites of revelle measurements both support the recharge discharge mjo theory time series of echo top heights indicate that convective deepening during the mjo onset occurs over a 12 16 day period composite statistics show evident recharging discharging features in convection and the environment population of shallow isolated convective cells sst cape and the lower tropospheric moisture increase recharge substantially approximately tw

observations of the madden julian oscillation during indian ocean dipole events 1 the characteristics of madden julian oscillation mjo development and propagation during indian ocean dipole iod events are presented in this study we find that mjo activity over the indian ocean and maritime continent is enhanced during negative iod and subdued during positive iod mjo events occurring during positive iod have weaker convection and less organized wind anomalies than those occurring during neutral or negative iod these differences are starkest over the eastern indian ocean where the iod has the greatest effect on low level humidity based on these observations and current mjo theories we posit that the iod primarily influences the mjo through its modulation of local low level moisture

the onset of convection in the madden julian oscillation abstract an observational study of the onset of convection in the madden julian oscillation mjo was performed composites of radiosonde data from the comprehensive aerological reference data set were constructed for an ensemble of tropical stations located in the indian ocean maritime continent and western pacific ocean the composites suggest that for the off equatorial stations used in this study the mjo period may be set by the buildup and discharge of the low level moist static energy this result supports the discharge recharge hypothesis of blade and hartmann mjo events appear to begin when the off equatorial atmosphere has been destabilized through a combination of low level moist static energy buildup and concurrent drying of the middle troposphere by subsidence in the wake of the previous cycle of mjo convection the low level moist static energy buildup is controlled by a corresponding increase in low level moisture the increase in low level moisture is not caused by the 1000 mb convergen

evolution properties and spatial variability of mjo convection near and off the equator during dynamo abstractthis study investigates the evolution structure and spatial variability of madden julian oscillation mjo convection observed during the 2011 12 dynamics of the mjo dynamo field campaign generally the c band radars located in the near equatorial indian ocean shared mobile atmospheric research and teaching radar smart r on addu atoll gan and nasa toga on the r v roger revelle revelle observed similar trends in echo top heights stratiform rain fraction and precipitation feature size across the mjo life cycle these trends are closely related to changes in mid to upper tropospheric moisture sea surface temperature sst zonal wind and diagnosed vertical air motions however the evolution of convection moisture and vertical air motion at the r v mirai mirai located in the intertropical convergence zone itcz at 8 s exhibited a pattern nearly opposite to gan and revelle when the mjo was active over the equator convection was suppressed around mirai owing to induced subsiden

drop size distributions and radar observations of convective and stratiform rain over the equatorial indian and west pacific oceans abstracttwo dimensional video disdrometer 2dvd data were analyzed from two equatorial indian gan and west pacific ocean manus islands where precipitation is primarily organized by the intertropical convergence zone and the madden julian oscillation mjo the 18 3 5 months of 2dvd data from manus gan island show that 1 the two sites have similar drop size distribution dsd spectra of liquid water content median diameter rain rate r radar reflectivity z normalized gamma number concentration nw and other integral rain parameters 2 there is a robust nw based separation between convective c and stratiform s dsds at both sites that produces consistent separation in other parameter spaces the 2dvd data indicate an equatorial maritime average c s rainfall accumulation fraction frequency of 81 19 41 59 at these locations it is hypothesized that convective fraction and frequency estimates are slightly higher than previous radar based studies because the ubiquitous weak shallow convec

evolution of the population of precipitating convective systems over the equatorial indian ocean in active phases of the madden julian oscillation three dimensional radar reflectivity fields from a dual wavelength doppler polarimetric radar s polka deployed in the equatorialindian ocean are used to evaluate the composition of the populationof convective cloud elements during active phases of the mjo rainfall in active periods was intermittent occurring in 11 episodesofabout 2 4days separated byseveralnonrainydays dataforthese 2 dayperiodswerecomposited relative to the time of maximum rainfall analysis of the s polka data shows the makeup of the convective population during the rainfall episodes four types of echo structures were analyzed statistically for the 11 rainfallepisodes shallowconvectiveechoes sce deepconvectivecores dcc wideconvectiveechocores wcc and broad stratiform bsr echo regions sce and dcc events were most frequent before the maximum rainfall with the peak frequency of sce leading that of dccs wccs were most frequent during therainfallmaximum and bsr regionswere most frequentinthe later part oftherainfallepisode composited ecmwf interim re analysis era interim data and 3 hourly atmospheric soundings indicate that the 2 4 day episodes were related to the passage of equatorial waves in the early part of a rainfall episode the wave passageconditionswereunstable favoringdeeppenetratingconvectiveelements whileinthelaterperiod the wave divergence profile was commensurate with convective systems in late anvil producing stages these results support the stretched building block notion of the life cycle of tropical convection and confirm satellitebased interpretations of sce dcc wcc and bsr statistics in the composition of the convective population

geographic and temporal patterns in the late neogene 12 3 ma aridification of europe the use of small mammals as paleoprecipitation proxies abstract present day relations between small mammal community structure and rainfall are used to predict late neogene 12 3 ma precipitation patterns in europe and anatolia new proxy methods are developed which include regressions of mean annual and minimum monthly precipitation on diet invertivory index and locomotion habitat arboreality index a series of precipitation maps and a set of regional precipitation curves through time at 1 myr resolution are presented precipitation curves at a higher temporal resolution are constructed for the region of central spain the miocene results show the existence between 12 and 9 ma of a large wet 800 1200 mm yr zone extending from northern spain to the ukraine and characterized by the whole year penetration of large amounts of moisture far into the continent between 10 9 and 5 ma this european temperate wet zone etwz shrinks and or moves northward resulting in diachronous aridification a coeval northward migration of the subtropical high pressure zone shpz is hypothesized which is also consistent with the predicted onset of seasonal summer dryness between 10 and 8 ma the maximum extension of the etwz at 12 9 ma temporally correlates with northern hemisphere cooling suggesting that climate zonation rather than the global amount of atmospheric moisture controlled european climate at this time the main aridification at 9 8 ma could best be explained by a northward extension shifting of the subtropical high pressure zone and a transition towards less zonal circulation processes which ultimately could have been triggered by uplift of the tibetan plateau a temporary increase of precipitation at 7 6 ma is associated with renewed global cooling the lowest precipitation values less than 400 mm yr occur during the pliocene in southern and eastern europe uplift in eastern europe carpathians shrinking of the paratethys could well explain the aridification in this area and the associated sharpening of east west precipitation gradients across the continent

latent heating characteristics of the mjo computed from trmm observations the tropical rainfall measurement mission s trmm spectral latent heating algorithm shows the contributions of different forms of convection to the latent heating profiles of the madden julian oscillation over the central indian and west pacific oceans in both oceanic regions storms containing broad stratiform regions produce increased upper level heating during active madden julian oscillation mjo phases the largest differences between the central indian and west pacific ocean heating are associated with heating produced by convective elements examination of the most extreme forms of convection shows that mesoscale organized convection often produces at least as much latent heat as young vigorous deep convection heating from nonextreme often midlevel topped convection is an important component of the mjo heating in both regions in all stages of the mjo over the central indian ocean the heating profile changes from having a maximum at 2 km due to nonextreme convection to a profile during the active stage that has two maxima one at 3 km due to nonextreme convection and 6 km owing to numerous mature mesoscale storms with broad stratiform precipitation components over the west pacific the maxima at 3 and 6 km are present in all mjo stages but the magnitude of the 6 km maximum sharply increases in the active mjo stage due to an increase in the number of storms with broad stratiform precipitation areas

late oligocene and miocene climate and vegetation in the eastern paratethys area northeast bulgaria based on pollen data abstract the results of palynological studies of the oligo miocene in the western part of the euxinian basin eastern paratethys are based on the analysis of 57 samples from core c 136a drilled near the town of balchik varna district some samples were barren or contained very little pollen and were not included in the analysis quantitative data are thus confined to 26 polleniferous samples we present results for the upper oligocene as well as the tarkhanian karaganian bessarabian and chersonian stages of the middle to upper miocene mixed deciduous forests were widespread during the time period studied swamp forests are also recorded with distribution maxima observed in the oligocene and in the bessarabian the widest extent of herbaceous vegetation is recorded in the late bessarabian and chersonian when it occupied open landscapes after a marine regressional phase the climatic data reconstructed by the coexistence approach indicate mean annual temperatures mats of ca 15 17 c and mean annual precipitation maps of 800 1300 mm for the upper oligocene the narrowest coexistence intervals of the tarkhanian and karaganian display mats of 14 17 c and maps of 800 1300 mm the most substantial data are for the bessarabian in which the lower part is characterized by mats of 15 6 16 6 c and maps from 800 1200 1300 mm the results for the upper part of the bessarabian are more variable especially with respect to precipitation that is generally lower 700 800 mm the same is true for the chersonian where besides lower precipitation lower annual temperature and temperature of coldest month are observed these results correlate with previous vegetation and palaeoclimate data from the forecarpathian basin nw bulgaria

cenozoic continental climatic evolution of central europe continental climate evolution of central europe has been reconstructed quantitatively for the last 45 million years providing inferred data on mean annual temperature and precipitation and winter and summer temperatures although some regional effects occur the european cenozoic continental climate record correlates well with the global oxygen isotope record from marine environments during the last 45 million years continental cooling is especially pronounced for inferred winter temperatures but hardly observable from summer temperatures correspondingly cenozoic cooling in central europe is directly associated with an increase of seasonality in contrast inferred cenozoic mean annual precipitation remained relatively stable indicating the importance of latent heat transport throughout the cenozoic moreover our data support the concept that changes in atmospheric co2 concentrations although linked to climate changes were not the major driving force of cenozoic cooling

a method for climatic reconstruction of the mediterranean pliocene using pollen data pollen data from numerous sites around the mediterranean sea indicate that several important vegetation and climatic changes occurred during the pliocene these data are in good agreement with pollen records from northwest europe and with 18o curves from mediterranean and atlantic deep sea cores quantitative palaeoclimatic reconstructions from pliocene pollen data of the mediterranean region cannot be based on conventional modern analogue techniques as individual pliocene pollen spectra contain taxa representing temperate warm temperate and subtropical plants that do not grow together today instead we propose a new method that uses a climatic amplitude method modified to take partially into account the relative abundances of the taxa we applied this method to the pliocene garraf 1 palynological sequence from catalonia which provides a long continuous record of climatic change from 5 3 ma to the early pleistocene we estimate that annual temperatures were 1 to 5 c higher than today and the annual precipitation 400 to 1000 mm higher than today prior to the beginning of the late cenozoic glacial interglacial cycles in contrast temperature and precipitation both fell sharply during the glacial phases of the earliest glacial interglacial cycles

microphysical characteristics of mjo convection over the indian ocean during dynamo the microphysical characteristics of precipitating convection occurring in various stages of the madden julian oscillation mjo over the indian ocean are determined from data obtained from the national center for atmospheric research dual polarimetric doppler s band radar s polka deployed as part of the dynamics of the mjo dynamo field experiment active mjo events with increased rainfall occurred in october november and december 2011 during each of these active mjo phases in addition to enhanced rainfall convection became deeper and ice phase microphysics played a greater role s polka consistently showed nonoriented small ice particles dominating the radar echoes at altitudes of 9 10 km dry aggregates concentrated between 7 and 9 km and wet aggregates and graupel near the melting level 5 km graupel occurred mainly in actively convective towers while the wet aggregates occurred almost exclusively in the stratiform regions of mesoscale convective systems mcss during each of the three multiweek mjo active phases the maximum rainfall occurred in short bursts lasting a few days each multiday rainy period began with deepening convective elements and a concurrent increase in occurrence of dry aggregates which maximized just prior to organization into mcss the peak rainfall occurrence coincided with the maximum coverage of the radar domain by mcss reflecting large stratiform regions that exhibited the most frequent occurrence of wet aggregates during the december active mjo phase however the mcss were shallower and had a slightly lower tendency for wet aggregates in the stratiform regions and therefore generally weaker brightbands

mesoscale convective systems 1 mesoscale convective systems mcss have regions of both convective and stratiform precipitation and they develop mesoscale circulations as they mature the upward motion takes the form of a deep layer ascent drawn into the mcs in response to the latent heating and cooling in the convective region the ascending layer overturns as it rises but overall retains a coherent layer structure a middle level layer of inflow enters the stratiform region of the mcs from a direction determined by the large scale flow and descends in response to diabatic cooling at middle to low levels a middle level mesoscale convective vortex mcv develops in the stratiform region prolongs the mcs and may contribute to tropical cyclone development the propagation of an mcs may have a discrete component but may further be influenced by waves and disturbances generated both in response to the mcs and external to the mcs waves of a larger scale may affect the propagation velocity by phase locking with the mcs in a cooperative mode the horizontal scale of an mcs may be limited either by a balance between the formation rate of convective precipitation and dissipation of stratiform precipitation or by the rossby radius of the mcv the vertical redistribution of momentum by an mcs depends on the size of the stratiform region while the net vertical profile of heating of the large scale environment depends on the amount of stratiform rain regional variability of the stratiform rain from mcss affects the large scale circulation s response to mcs heating

palaeogeographic environment during the desiccation of the black sea abstract during the latest chersonian about 10 3 m y ago tectonic movements took place leading to an elevation of the crimean caucasian chain and to an isolation of the fore caucasian part of the black sea basin this part of the basin had been draining the rivers of the russian platform and after the isolation it became desalinized while the main part of the black sea basin was almost desiccated and evaporites mainly dolomites formed in it due to the predominant calcium magnesium carbonate composition of the chersonian sea waters these dolomites are found in the drillings of dsdp leg 42b and are confirmed geophysically the tectonic movements during the latest chersonian led to the formation of a series of grabens along which the mediterranean sea invaded the north aegean area and a little later during the early maeotian the black sea

ice crystal habits and growth processes in stratiform clouds with embedded convection examined through aircraft observation in northern china abstractice crystal habits and growth processes in two cases of stratiform clouds with embedded convection are investigated using data observed simultaneously from three aircraft on 18 april 2009 and 1 may 2009 as part of the beijing cloud experiment bce the results show that the majority of ice crystal habits found in the two cases at temperatures between 0 and 16 c included platelike needle column capped column dendrite and irregular a mixture of several ice crystal habits was identified in all of the clouds studied however the ice crystals recorded in the embedded convection regions contained more dendrites and possessed heavier riming degrees and the ice crystals identified in the stratiform clouds contained more hexagonal plate crystals both riming and aggregation processes played central roles in the broadening of particle size distributions psds and these processes were more active in embedded convection regions than in stratiform regions however riming was more prevalent in the

partitioning tropical oceanic convective and stratiform rains by draft strength the discrimination of convective from stratiform tropical oceanic rains by conventional radar based textural methods is problematic because of the small size and modest horizontal reflectivity gradients of the oceanic convective cells in this work the vertical air motion measured by an aircraft gust probe is used as a discriminator which is independent of the textural methods a threshold draft magnitude of 1 m s 1 separates the two rain types simultaneous airborne in situ observations of drop size distributions dsd made during the tropical ocean global atmosphere coupled ocean atmosphere response experiment toga coare were used to compute z r and other integral parameters the data were quality controlled to minimize misclassifications the convective and stratiform rains observed just below the melting level but adjusted to surface air density are characterized by power law z r relations z 129r1 38 convective and 224r1 28 stratiform however at r 10 mm h 1 the convective population is essentially coincident with the small drop size small z portion of the stratiform population tokay and short 1996 found a similar result when their algorithm did not separate the rain types unambiguously at r 10 mm h 1 the physical reasons for the wide variability of the drop size spectra and z r points in stratiform rain and their overlap with that of convective rain are proposed the subtle distinctions in the microphysical properties and the z r relations by rain type could not be found by yuter and houze yh using the same airborne dsd data set as that in this work and a radar based textural classification algorithm

clouds associated with the madden julian oscillation a new perspective from cloudsat abstractthe evolution of total cloud cover and cloud types is composited across the madden julian oscillation mjo using cloudsat data for june 2006 may 2010 two approaches are used to define mjo phases 1 the local phase is determined at each longitude and time from filtered outgoing longwave radiation and 2 the global phase is defined using a popular real time multivariate mjo rmm index which assigns the tropics to an mjo phase each day in terms of local phase cloudsat results show a familiar evolution of cloud type predominance in the growing stages shallow clouds coexist with deep intense but narrow convective systems widespread cloud coverage and rainfall appear during the active phases becoming more anvil dominated with time and finally suppressed conditions return results are compared to the convectively coupled kelvin wave which has a similar life cycle to the mjo convection in the mjo tends to be modulated more by moisture variations compared to the kelvin wave in terms of globa

late miocene climate in the circum alpine realm a quantitative analysis of terrestrial palaeofloras abstract selected mega and microfloras from central and southern europe have been analysed for the time interval tortonian pannonian mn 9 12 with the coexistence approach to obtain quantitative palaeoclimate data the results give a geographically differentiated picture of the late miocene climate in the circum alpine area spatial patterns are presented in maps for mean annual temperature temperature of the coldest month temperature of the warmest month mean annual precipitation and mean annual range of temperature the obtained data show an overall warm humid and homogenous climate with very low latitudinal and longitudinal gradients there is no indication of a mediterranean type of climate palaeogeographic influences on climate patterns are evident the pannonian lake caused mild winters and a lower seasonality of temperature in the pannonian basin