scholarly journals GPS radio occultation with CHAMP and SAC-C: global monitoring of thermal tropopause parameters

2005 ◽  
Vol 5 (6) ◽  
pp. 1473-1488 ◽  
Author(s):  
T. Schmidt ◽  
S. Heise ◽  
J. Wickert ◽  
G. Beyerle ◽  
C. Reigber
Keyword(s):  
Standard Deviation ◽  
Potential Temperature ◽  
Weather Forecast ◽  
Lapse Rate ◽  
Radiosonde Data ◽  
Temperature Profiles ◽  
Quasi Biennial Oscillation ◽  
Data Set ◽  
Medium Range Weather Forecast ◽  
Satellite Missions

Abstract. In this study the global lapse-rate tropopause (LRT) pressure, temperature, potential temperature, and sharpness are discussed based on Global Positioning System (GPS) radio occultations (RO) from the German CHAMP (CHAllenging Minisatellite Payload) and the U.S.-Argentinian SAC-C (Satelite de Aplicaciones Cientificas-C) satellite missions. Results with respect to seasonal variations are compared with operational radiosonde data and ECMWF (European Centre for Medium-Range Weather Forecast) operational analyses. Results on the tropical quasi-biennial oscillation (QBO) are updated from an earlier study. CHAMP RO data are available continuously since May 2001 with on average 150 high resolution temperature profiles per day. SAC-C data are available for several periods in 2001 and 2002. In this study temperature data from CHAMP for the period May 2001-December 2004 and SAC-C data from August 2001-October 2001 and March 2002-November 2002 were used, respectively. The bias between GPS RO temperature profiles and radiosonde data was found to be less than 1.5K between 300 and 10hPa with a standard deviation of 2-3K. Between 200-20hPa the bias is even less than 0.5K (2K standard deviation). The mean deviations based on 167699 comparisons between CHAMP/SAC-C and ECMWF LRT parameters are (-2.1±37.1)hPa for pressure and (0.1±4.2)K for temperature. Comparisons of LRT pressure and temperature between CHAMP and nearby radiosondes (13230) resulted in (5.8±19.8)hPa and (-0.1±3.3)K, respectively. The comparisons between CHAMP/SAC-C and ECMWF show on average the largest differences in the vicinity of the jet streams with up to 700m in LRT altitude and 3K in LRT temperature, respectively. The CHAMP mission generates the first long-term RO data set. Other satellite missions will follow (GRACE, COSMIC, MetOp, TerraSAR-X, EQUARS) generating together some thousand temperature profiles daily.

scholarly journals Two decades of in-situ temperature measurements in the upper troposphere and lowermost stratosphere from IAGOS long-term routine observation

2017 ◽  
Author(s):  
Florian Berkes ◽  
Patrick Neis ◽  
Martin G. Schultz ◽  
Ulrich Bundke ◽  
Susanne Rohs ◽  
...  
Keyword(s):  
Weather Forecast ◽  
Global Scale ◽  
Temperature Trend ◽  
Data Set ◽  
Medium Range Weather Forecast ◽  
Upper Troposphere ◽  
Temperature Trends ◽  
Geographical Regions

Abstract. Despite several studies on temperature trends in the tropopause region, a comprehensive understanding of the evolution of temperatures in this climate-sensitive region of the atmosphere remains elusive. Here we present a unique global-scale, long-term data set of high-resolution in-situ temperature data measured aboard passenger aircraft within the European Research Infrastructure IAGOS (In-service Aircraft for a Global Observing System, www.iagos.org). This data set is used to investigate temperature trends within the global upper troposphere and lowermost stratosphere (UTLS) for the period 1995 to 2012 in different geographical regions and vertical layers of the UTLS. The largest amount of observations is available over the North Atlantic. Here, a neutral temperature trend is found within the lowermost stratosphere. This contradicts the temperature trend in the European Centre for Medium Range Weather Forecast (ECMWF) ERA-Interim reanalysis, where a significant (95 % confidence) temperature increase of +0.56 K/decade is obtained. Differences between trends derived from observations and reanalysis data can be traced back to changes in the temperature bias between observation and model data over the studied period. This study demonstrates the value of the IAGOS temperature observations as anchor point for the evaluation of reanalyses and its suitability for independent trend analyses.

scholarly journals Widespread polar stratospheric ice clouds in the 2015/2016 Arctic winter – Implications for ice nucleation

2017 ◽  
Author(s):  
Christiane Voigt ◽  
Andreas Dörnbrack ◽  
Martin Wirth ◽  
Silke M. Groß ◽  
Michael C. Pitts ◽  
...  
Keyword(s):  
Weather Forecast ◽  
Satellite Observation ◽  
Reanalysis Data ◽  
Ice Nucleation ◽  
The Arctic ◽  
Orthogonal Polarization ◽  
Data Set ◽  
Ice Clouds ◽  
Medium Range Weather Forecast ◽  
Cold Temperatures

Abstract. Low planetary wave activity led to a stable vortex with exceptionally cold temperatures in the 2015/2016 Arctic winter. Extended areas with temperatures below the ice frost point Tice persisted over weeks in the Arctic stratosphere as derived from the 36-years temperature climatology of the ERA-Interim reanalysis data set of the European Center for Medium Range Weather Forecast ECMWF. These extreme conditions promoted the formation of widespread polar stratospheric ice clouds (ice PSCs). The space-borne Cloud-Aerosol Lidar with Orthogonal Polarization CALIOP instrument onboard the CALIPSO satellite (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) continuously measured ice PSCs for about a month with maximum extensions of up to 2 × 106 km2 in the stratosphere. On 22 January 2016, the WALES (Water Vapor Lidar Experiment in Space – airborne demonstrator) lidar onboard the High Altitude and Long Range Research Aircraft HALO detected an ice PSC with a horizontal length of more than 1400 km. The ice PSC extended between 18 and 24 km altitude and was surrounded by nitric acid trihydrate (NAT) particles, supercooled ternary solution (STS) droplets and particle mixtures. The ice PSC occurrence in the backscatter ratio to depolarization optical space spanned by WALES observations is best matched by defining the inverse backscatter ratio of 0.3 as 1/Rice|NAT threshold between ice and NAT cloud regions. In addition, the histogram clearly shows two distinct branches in ice PSC occurrence, indicative for two ice formation pathways. In addition to ice nucleation in STSm with meteoric dust inclusions, ice nucleation on pre-existing NAT may play a role in the Arctic winter 2015/2016. This hypothesis is supported by differences in the ECMWF trajectory analysis for the two ice branches. The observation of widespread Arctic ice PSCs can advance our understanding of ice nucleation in cold polar and tropical latitudes. It further provides a new observational data base for the parameterization of ice nucleation schemes in atmospheric models.

Operational predictability of winter blocking at ECMWF: an update

1995 ◽  
Vol 13 (3) ◽  
pp. 305-317 ◽  
Author(s):  
S. Tibaldi ◽  
P. Ruti ◽  
E. Tosi ◽  
M. Maruca
Keyword(s):  
Initial Value Problem ◽  
Weather Forecast ◽  
Model Resolution ◽  
Initial Value ◽  
Atlantic Region ◽  
Data Set ◽  
Medium Range Weather Forecast ◽  
Medium Range ◽  
Limited Length ◽  
Diagnostic Work

Abstract. Seven winters of analyses and forecasts from the operational archives of the European Centre for Medium Range Weather Forecast had been previously analyzed to assess the performance of the model in forecasting blocking events. This work updates some of this previous diagnostic work to the last five winters, from 1987/88 to 1991/92. The data set therefore covers all winter seasons (DJF) from 1980/81 to 1991/92, and consists of daily northern hemisphere 500 hPa geopotential height analyses and of the ten corresponding forecasts verifying on the same day ("Lorenz data"). Local blocking and sector blocking have been defined, using different modifications of the original Lejenas and Økland index. The comparison between the first seven and the last five winters, within the restrictions imposed by limited length of the data set, suggests a much improved situation as far as model climatology of blocking is concerned, especially over the Euro-Atlantic region. Operational predictability of blocking as an initial value problem is also shown to be measurably improved, in both Atlantic and Pacific sectors. All such improvements are shown to have taken place together with a considerable reduction of the model systematic error. Nevertheless, forecasting blocking in the medium range remains a difficult task for the model. More work is needed to understand whether the improvements are to be ascribed to the increased model resolution or to better physical parametrisations.

scholarly journals Validation of COSMIC water vapor data in the upper troposphere and lower stratosphere using MLS, MERRA and ERA-Interim

2016 ◽  
Author(s):  
Ming Shangguan ◽  
Katja Matthes ◽  
Wuke Wang ◽  
Tae-Kwon Wee
Keyword(s):  
Water Vapor ◽  
Seasonal Cycle ◽  
Lower Stratosphere ◽  
Southern Oscillation ◽  
Weather Forecast ◽  
Cosmic Radio ◽  
Quasi Biennial Oscillation ◽  
Medium Range Weather Forecast ◽  
Upper Troposphere ◽  
The Antarctic

Abstract. Water vapor is the most important greenhouse gas in the atmosphere with important implications not only for the Earth’s radiation and energy budget but also for various chemical, physical and dynamical processes in the stratosphere. The Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Radio Occultation (RO) dataset from 2007 through 2013 is used for the first time to study the distribution and variability water vapor in the upper troposphere and lower stratosphere (UTLS). The COSMIC data are compared to the Microwave Limb Sounder (MLS) data, and to two global reanalyses: The Modern-Era Retrospective analysis for Research and Application (MERRA) of the National Aeronautics and Space Administration (NASA); and, the latest reanalysis of the European Center for Medium-range Weather Forecast (ECMWF), the ERA-Interim. The MLS data have been assimilated into the MERRA, whereas the COSMIC data are used for the ERA-Interim. As a result, the MERRA agrees well with the MLS data and so does the ERA-Interim with the COSMIC data. While the monthly zonal mean distributions of water vapor from the four datasets show good agreements in northern mid-latitudes, large discrepancies exist in high southern latitudes and tropics. The MERRA shows overall a consistent seasonal cycle with MLS, but has too strong winter dehydration over the Antarctic, and is very weak in the interannual variations. The ERA-Interim fails to properly represent the winter dehydration over the Antarctic, and shows an unrealistic seasonal cycle in the tropical upper troposphere. The COSMIC data shows a good agreement with the MLS data except for the tropical "taper recorder" signal, where the COSMIC data suggest a faster upward motion than the MLS data. The COSMIC data are able to represent the moisture variabilities associated with the Quasi-Biennial Oscillation and the El Niño-Southern Oscillation.

scholarly journals 30 years of upper air soundings on board of R/V <i>POLARSTERN</i>

2016 ◽  
Vol 8 (1) ◽  
pp. 213-220 ◽  
Author(s):  
Amelie Driemel ◽  
Bernd Loose ◽  
Hannes Grobe ◽  
Rainer Sieger ◽  
Gert König-Langlo
Keyword(s):  
Austral Summer ◽  
Weather Forecast ◽  
The Arctic ◽  
Radiosonde Data ◽  
Data Sets ◽  
Polar Regions ◽  
Data Set ◽  
Northern Summer ◽  
Special Value ◽  
Remote Sensing Systems

Abstract. The research vessel and supply icebreaker POLARSTERN is the flagship of the Alfred-Wegener-Institut in Bremerhaven (Germany) and one of the infrastructural pillars of German Antarctic research. Since its commissioning in 1982, POLARSTERN has conducted 30 campaigns to Antarctica (157 legs, mostly austral summer), and 29 to the Arctic (94 legs, northern summer). Usually, POLARSTERN is more than 300 days per year in operation and crosses the Atlantic Ocean in a meridional section twice a year. The first radiosonde on POLARSTERN was released on the 29 December 1982, 2 days after POLARSTERN started on its maiden voyage to the Antarctic. And these daily soundings have continued up to the present. Due to the fact that POLARSTERN has reliably and regularly been providing upper air observations from data sparse regions (oceans and polar regions), the radiosonde data are of special value for researchers and weather forecast services alike. In the course of 30 years (29 December 1982 to 25 November 2012) a total of 12 378 radiosonde balloons were started on POLARSTERN. All radiosonde data can now be found at König-Langlo (2015, doi:10.1594/PANGAEA.810000). Each data set contains the directly measured parameters air temperature, relative humidity and air pressure, and the derived altitude, wind direction and wind speed. 432 data sets additionally contain ozone measurements.Although more sophisticated techniques (meteorological satellites, aircraft observation, remote-sensing systems, etc.) have nowadays become increasingly important, the high vertical resolution and quality of radiosonde data remains paramount for weather forecasts and modelling approaches.

scholarly journals Variability and trends in total and vertically resolved stratospheric ozone

2006 ◽  
Vol 6 (4) ◽  
pp. 6317-6368 ◽  
Author(s):  
D. Brunner ◽  
J. Staehelin ◽  
J. A. Maeder ◽  
I. Wohltmann ◽  
G. E. Bodeker
Keyword(s):  
Solar Cycle ◽  
Regression Model ◽  
Ozone Depletion ◽  
Lower Stratosphere ◽  
Potential Temperature ◽  
Three Dimensional ◽  
Volcanic Eruptions ◽  
Quasi Biennial Oscillation ◽  
Data Set ◽  
Total Column Ozone

Abstract. Trends in ozone columns and vertical distributions were calculated for the period 1979–2004 based on the three-dimensional ozone data set CATO (Candidoz Assimilated Three-dimensional Ozone) using a multiple linear regression model. CATO has been reconstructed from TOMS, GOME and SBUV total column ozone observations in an equivalent latitude and potential temperature framework and offers a pole to pole coverage of the stratosphere on 15 potential temperature levels. The regression model includes explanatory variables describing the influence of the quasi-biennial oscillation, volcanic eruptions, the solar cycle, the Brewer-Dobson circulation, Arctic ozone depletion, and the increase in stratospheric chlorine. The effects of displacements of the polar vortex and jet streams due to planetary waves, which may significantly affect trends at a given geographical latitude, are eliminated in the equivalent latitude framework. Ozone variability is largely explained by the QBO and stratospheric aerosol loading and the spatial structure of their influence is in good agreement with previous studies. The solar cycle signal peaks at about 30 to 35 km altitude which is lower than reported previously, and no negative signal is found in the tropical lower stratosphere. The Brewer-Dobson circulation shows a dominant contribution to interannual variability at both high and low latitudes and accounts for some of the ozone increase seen in the northern hemisphere since the mid-1990s. Arctic ozone depletion significantly affects the high northern latitudes between January and March and extends its influence to the mid-latitudes during later months. The vertical distribution of the ozone trend shows distinct negative trends at about 18 km in the lower stratosphere with largest declines over the poles, and above 35 km in the upper stratosphere. A narrow band of large negative trends extends into the tropical lower stratosphere. Assuming that the observed negative trend before 1995 continued to 2004 cannot explain the ozone changes since 1996. A model accounting for recent changes in EESC, aerosols and Eliassen-Palm flux, on the other hand, closely tracks ozone changes since 1995.

scholarly journals Variability and trends in total and vertically resolved stratospheric ozone based on the CATO ozone data set

2006 ◽  
Vol 6 (12) ◽  
pp. 4985-5008 ◽  
Author(s):  
D. Brunner ◽  
J. Staehelin ◽  
J. A. Maeder ◽  
I. Wohltmann ◽  
G. E. Bodeker
Keyword(s):  
Regression Model ◽  
Ozone Depletion ◽  
Lower Stratosphere ◽  
Stratospheric Ozone ◽  
Potential Temperature ◽  
Volcanic Eruptions ◽  
Quasi Biennial Oscillation ◽  
Data Set ◽  
Lower Altitude ◽  
Ozone Data

Abstract. Trends in ozone columns and vertical distributions were calculated for the period 1979–2004 based on the ozone data set CATO (Candidoz Assimilated Three-dimensional Ozone) using a multiple linear regression model. CATO has been reconstructed from TOMS, GOME and SBUV total column ozone observations in an equivalent latitude and potential temperature framework and offers a pole to pole coverage of the stratosphere on 15 potential temperature levels. The regression model includes explanatory variables describing the influence of the quasi-biennial oscillation (QBO), volcanic eruptions, the solar cycle, the Brewer-Dobson circulation, Arctic ozone depletion, and the increase in stratospheric chlorine. The effects of displacements of the polar vortex and jet streams due to planetary waves, which may significantly affect trends at a given geographical latitude, are eliminated in the equivalent latitude framework. The QBO shows a strong signal throughout most of the lower stratosphere with peak amplitudes in the tropics of the order of 10–20% (peak to valley). The eruption of Pinatubo led to annual mean ozone reductions of 15–25% between the tropopause and 23 km in northern mid-latitudes and to similar percentage changes in the southern hemisphere but concentrated at altitudes below 17 km. Stratospheric ozone is elevated over a broad latitude range by up to 5% during solar maximum compared to solar minimum, the largest increase being observed around 30 km. This is at a lower altitude than reported previously, and no negative signal is found in the tropical lower stratosphere. The Brewer-Dobson circulation shows a dominant contribution to interannual variability at both high and low latitudes and accounts for some of the ozone increase seen in the northern hemisphere since the mid-1990s. Arctic ozone depletion significantly affects the high northern latitudes between January and March and extends its influence to the mid-latitudes during later months. The vertical distribution of the ozone trend shows distinct negative trends at about 18 km in the lower stratosphere with largest declines over the poles, and above 35 km in the upper stratosphere. A narrow band of large negative trends extends into the tropical lower stratosphere. Assuming that the observed negative trend before 1995 continued to 2004 cannot explain the ozone changes since 1996. A model accounting for recent changes in equivalent effective stratospheric chlorine, aerosols and Eliassen-Palm flux, on the other hand, closely tracks ozone changes since 1995.

scholarly journals Contrasting ice formation in Arctic clouds: surface-coupled vs. surface-decoupled clouds

2021 ◽  
Vol 21 (13) ◽  
pp. 10357-10374
Author(s):  
Hannes J. Griesche ◽  
Kevin Ohneiser ◽  
Patric Seifert ◽  
Martin Radenz ◽  
Ronny Engelmann ◽  
...  
Keyword(s):  
Potential Temperature ◽  
The Arctic ◽  
Radiosonde Data ◽  
Ice Formation ◽  
Cloud Base ◽  
Data Set ◽  
Thermodynamic Structure ◽  
Cloud Radar ◽  
Lower Magnitude ◽  
Surface Coupling

Abstract. In the Arctic summer of 2017 (1 June to 16 July) measurements with the OCEANET-Atmosphere facility were performed during the Polarstern cruise PS106. OCEANET comprises amongst other instruments the multiwavelength polarization lidar PollyXT_OCEANET and for PS106 was complemented with a vertically pointed 35 GHz cloud radar. In the scope of the presented study, the influence of cloud height and surface coupling on the probability of clouds to contain and form ice is investigated. Polarimetric lidar data were used for the detection of the cloud base and the identification of the thermodynamic phase. Both radar and lidar were used to detect cloud top. Radiosonde data were used to derive the thermodynamic structure of the atmosphere and the clouds. The analyzed data set shows a significant impact of the surface-coupling state on the probability of ice formation. Surface-coupled clouds were identified by a quasi-constant potential temperature profile from the surface up to liquid layer base. Within the same minimum cloud temperature range, ice-containing clouds have been observed more frequently than surface-decoupled clouds by a factor of up to 6 (temperature intervals between −7.5 and −5 ∘C, 164 vs. 27 analyzed intervals of 30 min). The frequency of occurrence of surface-coupled ice-containing clouds was found to be 2–3 times higher (e.g., 82 % vs. 35 % between −7.5 and −5 ∘C). These findings provide evidence that above −10 ∘C heterogeneous ice formation in Arctic mixed-phase clouds occurs by a factor of 2–6 more often when the cloud layer is coupled to the surface. In turn, for minimum cloud temperatures below −15 ∘C, the frequency of ice-containing clouds for coupled and decoupled conditions approached the respective curve for the central European site of Leipzig, Germany (51∘ N, 12∘ E). This corroborates the hypothesis that the free-tropospheric ice nucleating particle (INP) reservoir over the Arctic is controlled by continental aerosol. Two sensitivity studies, also using the cloud radar for detection of ice particles and applying a modified coupling state detection, both confirmed the findings, albeit with a lower magnitude. Possible explanations for the observations are discussed by considering recent in situ measurements of INP in the Arctic, of which much higher concentrations were found in the surface-coupled atmosphere in close vicinity to the ice shore.

scholarly journals Mesoscale temperature fluctuations in the stratosphere

2006 ◽  
Vol 6 (4) ◽  
pp. 7369-7406
Author(s):  
B. L. Gary
Keyword(s):  
Cross Sections ◽  
Potential Temperature ◽  
Temperature Fluctuations ◽  
Vertical Displacement ◽  
Horizontal Resolution ◽  
Lapse Rate ◽  
Back Trajectory ◽  
Temperature Profiles ◽  
Synoptic Scale ◽  
Jet Streams

Abstract. An airborne instrument that measures altitude temperature profiles is ideally suited for the task of characterizing statistical properties of the vertical displacement of isentrope surfaces. Prior measurements of temperature fluctuations during level flight could not be used to infer isentrope altitude variations because lapse rate information was missing. The Microwave Temperature Profiler instrument, which includes lapse rate measurements at flight level as a part of temperature profiles, has been used on hundreds of flights to produce altitude versus ground track cross-sections of potential temperature. These cross-sections show isentrope altitude variations with a horizontal resolution of ~3 km for a >6 km altitude region. An airborne isentrope-altitude cross-section (IAC) can be compared with a counterpart IAC generated from synoptic scale data, based on radiosondes and satellite instruments, in order to assess differences between the altitudes of isentrope surfaces sampled at mesoscale versus synoptic scale. It has been found that the synoptic scale isentropes fail to capture a significant component of vertical displacement of isentrope surfaces, especially in the vicinity of jet streams. Under the assumptions that air parcels flow along isentrope surfaces, and change temperature adiabatically while undergoing altitude displacements, it is possible to compute mesoscale temperature fluctuations that are not present in synoptic scale back trajectory parcel temperature histories. It has been found that the magnitude of the mesoscale component of temperature fluctuations varies with altitude, season, latitude and underlying topography. A model for these dependences is presented, which shows, for example, that mesoscale temperature fluctuations increase with altitude in a systematic way, are greatest over mountainous terrain, and are greater at polar latitudes during winter.

scholarly journals Potential vorticity structure of embedded convection in a warm conveyor belt and its relevance for large-scale dynamics

2020 ◽  
Vol 1 (1) ◽  
pp. 127-153 ◽  
Author(s):  
Annika Oertel ◽  
Maxi Boettcher ◽  
Hanna Joos ◽  
Michael Sprenger ◽  
Heini Wernli
Keyword(s):  
Potential Vorticity ◽  
Large Scale ◽  
Potential Temperature ◽  
Weather Forecast ◽  
Conveyor Belt ◽  
Medium Range Weather Forecast ◽  
Cloud Band ◽  
Upper Troposphere ◽  
Surface Precipitation ◽  
Flow Evolution

Abstract. Warm conveyor belts (WCBs) are important airstreams in extratropical cyclones. They can influence large-scale flow evolution by modifying the potential vorticity (PV) distribution during their cross-isentropic ascent. Although WCBs are typically described as slantwise-ascending and stratiform-cloud-producing airstreams, recent studies identified convective activity embedded within the large-scale WCB cloud band. However, the impacts of this WCB-embedded convection have not been investigated in detail. In this study, we systematically analyze the influence of embedded convection in an eastern North Atlantic WCB on the cloud and precipitation structure, on the PV distribution, and on larger-scale flow. For this reason, we apply online trajectories in a high-resolution convection-permitting simulation and perform a composite analysis to compare quasi-vertically ascending convective WCB trajectories with typical slantwise-ascending WCB trajectories. We find that the convective WCB ascent leads to substantially stronger surface precipitation and the formation of graupel in the middle to upper troposphere, which is absent for the slantwise WCB category, indicating the key role of WCB-embedded convection for precipitation extremes. Compared to the slantwise WCB trajectories, the initial equivalent potential temperature of the convective WCB trajectories is higher, and the convective WCB trajectories originate from a region of larger potential instability, which gives rise to more intense cloud diabatic heating and stronger cross-isentropic ascent. Moreover, the signature of embedded convection is distinctly imprinted in the PV structure. The diabatically generated low-level positive PV anomalies, associated with a cyclonic circulation anomaly, are substantially stronger for the convective WCB trajectories. The slantwise WCB trajectories lead to the formation of a widespread region of low-PV air (that still have weakly positive PV values) in the upper troposphere, in agreement with previous studies. In contrast, the convective WCB trajectories form mesoscale horizontal PV dipoles at upper levels, with one pole reaching negative PV values. On a larger scale, these individual mesoscale PV anomalies can aggregate to elongated PV dipole bands extending from the convective updraft region, which are associated with coherent larger-scale circulation anomalies. An illustrative example of such a convectively generated PV dipole band shows that within around 10 h the negative PV pole is advected closer to the upper-level waveguide, where it strengthens the isentropic PV gradient and contributes to the formation of a jet streak. This suggests that the mesoscale PV anomalies produced by embedded convection upstream organize and persist for several hours and therefore can influence the synoptic-scale circulation. They thus can be dynamically relevant, influence the jet stream and (potentially) the downstream flow evolution, which are highly relevant aspects for medium-range weather forecast. Finally, our results imply that a distinction between slantwise and convective WCB trajectories is meaningful because the convective WCB trajectories are characterized by distinct properties.

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