scholarly journals Intercomparison between Lagrangian and Eulerian simulations of the development of mid-latitude streamers as observed by CRISTA

2005 ◽  
Vol 5 (1) ◽  
pp. 85-95 ◽  
Author(s):  
F. Khosrawi ◽  
J.-U. Grooß ◽  
R. Müller ◽  
P. Konopka ◽  
W. Kouker ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Transport Processes ◽  
Lagrangian Model ◽  
Function Technique ◽  
Small Scale ◽  
Mixing Ratios ◽  
Infrared Spectrometer ◽  
The Impact ◽  
Small Scale Structures

Abstract. During the CRISTA-1 mission three pronounced fingerlike structures reaching from the lower latitudes to the mid-latitudes, so-called streamers, were observed in the measurements of several trace gases in early November 1994. A simulation of these streamers in previous studies employing the KASIMA (Karlsruhe Simulation Model of the Middle Atmosphere) and ROSE (Research on Ozone in the Stratosphere and its Evolution) model, both being Eulerian models, show that their formation is due to adiabatic transport processes. Here, the impact of mixing on the development of these streamers is investigated. These streamers were simulated with the CLaMS model (Chemical Lagrangian Model of the Stratosphere), a Lagrangian model, using N2O as long-lived tracer. Using several different initialisations the results were compared to the KASIMA simulations and CRISTA (Cryogenic Infrared Spectrometer and Telescope for the Atmosphere) observations. Further, since the KASIMA model was employed to derive a 9-year climatology, the quality of the reproduction of streamers from such a study was tested by the comparison of the KASIMA results with CLaMS and CRISTA. The streamers are reproduced well for the Northern Hemisphere in the simulations of CLaMS and KASIMA for the 6 November 1994. However, in the CLaMS simulation a stronger filamentation is found while larger discrepancies between KASIMA and CRISTA were found especially for the Southern Hemisphere. Further, compared to the CRISTA observations the mixing ratios of N2O are in general underestimated in the KASIMA simulations. An improvement of the simulations with KASIMA was obtained for a simulation time according to the length of the CLaMS simulation. To quantify the differences between the simulations with CLaMS and KASIMA, and the CRISTA observations, the probability density function technique (PDF) is used to interpret the tracer distributions. While in the PDF of the KASIMA simulation the small scale structures observed by CRISTA are smoothed out due to the numerical diffusion in the model, the PDFs derived from CRISTA observations can be reproduced by CLaMS by optimising the mixing parameterisation. Further, this procedure gives information on small-scale variabilities not resolved by the CRISTA observations.

scholarly journals Intercomparison between Lagrangian and Eulerian simulations of the development of mid-latitude streamers as observed by CRISTA

2004 ◽  
Vol 4 (5) ◽  
pp. 6185-6212
Author(s):  
F. Khosrawi ◽  
J.-U. Grooß ◽  
R. Müller ◽  
P. Konopka ◽  
W. Kouker ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Transport Processes ◽  
Lagrangian Model ◽  
Function Technique ◽  
Small Scale ◽  
Mixing Ratios ◽  
Infrared Spectrometer ◽  
The Impact ◽  
Small Scale Structures

Abstract. During the CRISTA-1 mission three pronounced fingerlike structures reaching from the lower latitudes to the mid-latitudes, so-called streamers, were observed in the measurements of several trace gases in early November 1994. A simulation of these streamers in previous studies employing the KASIMA (Karlsruhe Simulation Model of the Middle Atmosphere) and ROSE (Research on Ozone in the Stratosphere and its Evolution) model, both being Eulerian models, show that their formation is due to adiabatic transport processes. Here, the impact of mixing on the development of these streamers is investigated. These streamers were simulated with the CLaMS model (Chemical Lagrangian Model of the Stratosphere), a Lagrangian model, using N2O as long-lived tracer. Using several different initialisations the results were compared to the KASIMA simulations and CRISTA (Cryogenic Infrared Spectrometer and Telescope for the Atmosphere) observations. Further, since the KASIMA model was employed to derive a 9-year climatology, the quality of the reproduction of streamers from such a study was tested by the comparison of the KASIMA results with CLaMS and CRISTA. The streamers are reproduced well for the Northern Hemisphere in the simulations of CLaMS and KASIMA for the 6 November 1994. However, in the CLaMS simulation a stronger filamentation is found while larger discrepancies between KASIMA and CRISTA were found especially for the Southern Hemisphere. Further, compared to the CRISTA observations the mixing ratios of N2O are in general underestimated in the KASIMA simulations. An improvement of the simulations with KASIMA was obtained for a simulation time according to the length of the CLaMS simulation. To quantify the differences between the simulations with CLaMS and KASIMA, and the CRISTA observations, the probability density function technique (PDF) is used to interpret the tracer distributions. While in the PDF of the KASIMA simulation the small scale structures observed by CRISTA are smoothed out due to the numerical diffusion in the model, the PDFs derived from CRISTA observations can be reproduced by CLaMS by optimizing the mixing parameterisation. Further, this procedure gives information on small-scale variabilities not resolved by the CRISTA observations.

scholarly journals Nitrification of the lowermost stratosphere during the exceptionally cold Arctic winter 2015–2016

2019 ◽  
Vol 19 (21) ◽  
pp. 13681-13699 ◽  
Author(s):  
Marleen Braun ◽  
Jens-Uwe Grooß ◽  
Wolfgang Woiwode ◽  
Sören Johansson ◽  
Michael Höpfner ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Cross Sections ◽  
Large Scale ◽  
Potential Temperature ◽  
Lagrangian Model ◽  
The Arctic ◽  
Small Scale ◽  
Mixing Ratios ◽  
Fine Structures ◽  
The Impact

Abstract. The Arctic winter 2015–2016 was characterized by exceptionally low stratospheric temperatures, favouring the formation of polar stratospheric clouds (PSCs) from mid-December until the end of February down to low stratospheric altitudes. Observations by GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on HALO (High Altitude and LOng range research aircraft) during the PGS (POLSTRACC–GW-LCYCLE II–SALSA) campaign from December 2015 to March 2016 allow the investigation of the influence of denitrification on the lowermost stratosphere (LMS) with a high spatial resolution. Two-dimensional vertical cross sections of nitric acid (HNO3) along the flight track and tracer–tracer correlations derived from the GLORIA observations document detailed pictures of wide-spread nitrification of the Arctic LMS during the course of an entire winter. GLORIA observations show large-scale structures and local fine structures with enhanced absolute HNO3 volume mixing ratios reaching up to 11 ppbv at altitudes of 13 km in January and nitrified filaments persisting until the middle of March. Narrow coherent structures tilted with altitude of enhanced HNO3, observed in mid-January, are interpreted as regions recently nitrified by sublimating HNO3-containing particles. Overall, extensive nitrification of the LMS between 5.0 and 7.0 ppbv at potential temperature levels between 350 and 380 K is estimated. The GLORIA observations are compared with CLaMS (Chemical Lagrangian Model of the Stratosphere) simulations. The fundamental structures observed by GLORIA are well reproduced, but differences in the fine structures are diagnosed. Further, CLaMS predominantly underestimates the spatial extent of HNO3 maxima derived from the GLORIA observations as well as the overall nitrification of the LMS. Sensitivity simulations with CLaMS including (i) enhanced sedimentation rates in case of ice supersaturation (to resemble ice nucleation on nitric acid trihydrate (NAT)), (ii) a global temperature offset, (iii) modified growth rates (to resemble aspherical particles with larger surfaces) and (iv) temperature fluctuations (to resemble the impact of small-scale mountain waves) slightly improved the agreement with the GLORIA observations of individual flights. However, no parameter could be isolated which resulted in a general improvement for all flights. Still, the sensitivity simulations suggest that details of particle microphysics play a significant role for simulated LMS nitrification in January, while air subsidence, transport and mixing become increasingly important for the simulated HNO3 distributions towards the end of the winter.

scholarly journals Nitrification of the lowermost stratosphere during the exceptionally cold Arctic winter 2015/16

2019 ◽  
Author(s):  
Marleen Braun ◽  
Jens-Uwe Grooß ◽  
Wolfgang Woiwode ◽  
Sören Johansson ◽  
Michael Höpfner ◽  
...  
Keyword(s):  
Cross Sections ◽  
Large Scale ◽  
Potential Temperature ◽  
Lagrangian Model ◽  
The Arctic ◽  
Small Scale ◽  
Mountain Waves ◽  
Mixing Ratios ◽  
Fine Structures ◽  
The Impact

Abstract. The Arctic winter 2015/16 was characterized by exceptionally cold stratospheric temperatures, favouring the formation of polar stratospheric clouds (PSCs) from mid-December until the end of February down to low stratospheric altitudes. Observations by GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on HALO (High Altitude and LOng range research aircraft) during the PGS (POLSTRACC/GW-LCYLCE II/SALSA) campaign from December 2015 to March 2016 allow an investigation of the influence of denitrification on the lowermost stratosphere (LMS) with a high spatial resolution. For the first time vertical cross-sections of nitric acid (HNO3) along the flight track and tracer-tracer correlations derived from the GLORIA observations document detailed pictures of wide-spread nitrification of the Arctic LMS during the course of an entire winter. GLORIA observations show large-scale structures and local fine structures with strongly enhanced absolute HNO3 volume mixing ratios reaching up to 11 ppbv at altitudes of 11 km in January and nitrified filaments persisting until the middle of March. Narrow streaks of enhanced HNO3, observed in mid-January, are interpreted as regions recently nitrified by sublimating HNO3-containing particles. Overall, a nitrification of the LMS between 5.0 ppbv and 7.0 ppbv at potential temperature levels between 350 and 380 K is estimated. This extent of nitrification has never been observed before in the Arctic lowermost stratosphere. The GLORIA observations are compared with CLaMS (Chemical Lagrangian Model of the Stratosphere) simulations. The fundamental structures observed by GLORIA are well reproduced, but differences in the fine structures are diagnosed. Further, CLaMS predominantly underestimates the spatial extent of maximum HNO3 mixing ratios derived from the GLORIA observations as well as the enhancement at lower altitudes. Sensitivity simulations with CLaMS including (i) enhanced sedimentation rates in case of ice supersaturation (to resemble ice nucleation on NAT), (ii) a global temperature offset, (iii) modified growth rates (to resemble aspherical particles with larger surfaces) and (iv) temperature fluctuations (to resemble the impact of small-scale mountain waves) mostly improve the agreement with the GLORIA observations. The sensitivity simulations suggest that details of particle microphysics play a significant role for simulated LMS nitrification in January, while air subsidence, transport and mixing become increasingly important towards the end of the winter.

scholarly journals Middle atmospheric water vapour and dynamics in the vicinity of the polar vortex during the Hygrosonde-2 campaign

2009 ◽  
Vol 9 (13) ◽  
pp. 4407-4417 ◽  
Author(s):  
S. Lossow ◽  
M. Khaplanov ◽  
J. Gumbel ◽  
J. Stegman ◽  
G. Witt ◽  
...  
Keyword(s):  
Water Vapour ◽  
Middle Atmosphere ◽  
Polar Vortex ◽  
The Arctic ◽  
Small Scale ◽  
Air Masses ◽  
Mixing Ratios ◽  
Water Vapour Concentration ◽  
Wind Shears

Abstract. The Hygrosonde-2 campaign took place on 16 December 2001 at Esrange/Sweden (68° N, 21° E) with the aim to investigate the small scale distribution of water vapour in the middle atmosphere in the vicinity of the Arctic polar vortex. In situ balloon and rocket-borne measurements of water vapour were performed by means of OH fluorescence hygrometry. The combined measurements yielded a high resolution water vapour profile up to an altitude of 75 km. Using the characteristic of water vapour being a dynamical tracer it was possible to directly relate the water vapour data to the location of the polar vortex edge, which separates air masses of different character inside and outside the polar vortex. The measurements probed extra-vortex air in the altitude range between 45 km and 60 km and vortex air elsewhere. Transitions between vortex and extra-vortex usually coincided with wind shears caused by gravity waves which advect air masses with different water vapour volume mixing ratios. From the combination of the results from the Hygrosonde-2 campaign and the first flight of the optical hygrometer in 1994 (Hygrosonde-1) a clear picture of the characteristic water vapour distribution inside and outside the polar vortex can be drawn. Systematic differences in the water vapour concentration between the inside and outside of the polar vortex can be observed all the way up into the mesosphere. It is also evident that in situ measurements with high spatial resolution are needed to fully account for the small-scale exchange processes in the polar winter middle atmosphere.

scholarly journals Observations of filamentary structures near the vortex edge in the Arctic winter lower stratosphere

2013 ◽  
Vol 13 (21) ◽  
pp. 10859-10871 ◽  
Author(s):  
C. Kalicinsky ◽  
J.-U. Grooß ◽  
G. Günther ◽  
J. Ungermann ◽  
J. Blank ◽  
...  
Keyword(s):  
Cross Sections ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Lagrangian Model ◽  
The Arctic ◽  
Small Scale ◽  
Air Mass ◽  
Mixing Ratios ◽  
Passive Tracers

Abstract. The CRISTA-NF (Cryogenic Infrared Spectrometers and Telescope for the Atmosphere – New Frontiers) instrument is an airborne infrared limb sounder operated aboard the Russian research aircraft M55-Geophysica. The instrument successfully participated in a large Arctic aircraft campaign within the RECONCILE (Reconciliation of essential process parameters for an enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) project in Kiruna (Sweden) from January to March 2010. This paper concentrates on the measurements taken during one flight of the campaign, which took place on 2 March in the vicinity of the polar vortex. We present two-dimensional cross-sections of derived volume mixing ratios for the trace gases CFC-11, O3, and ClONO2 with an unprecedented vertical resolution of about 500 to 600 m for a large part of the observed altitude range (≈ 6–19 km) and a dense horizontal sampling along flight direction of ≈ 15 km. The trace gas distributions show several structures, for example a part of the polar vortex and a vortex filament, which can be identified by means of O3–CFC-11 tracer–tracer correlations. The observations made during this flight are interpreted using the chemistry and transport model CLaMS (Chemical Lagrangian Model of the Stratosphere). Comparisons of the observations with the model results are used to assess the performance of the model with respect to advection, mixing, and the chemistry in the polar vortex. These comparisons confirm the capability of CLaMS to reproduce even very small-scale structures in the atmosphere, which partly have a vertical extent of only 1 km. Based on the good agreement between simulation and observation, we use artificial (passive) tracers, which represent different air mass origins (e.g. vortex, tropics), to further analyse the CRISTA-NF observations in terms of the composition of air mass origins. These passive tracers clearly illustrate the observation of filamentary structures that include tropical air masses. A characteristic of the Arctic winter 2009/10 was a sudden stratospheric warming in December that led to a split of the polar vortex. The vortex re-established at the end of December. Our passive tracer simulations suggest that large parts of the re-established vortex consisted to about 45% of high- and mid-latitude air.

scholarly journals Evaluation of CLaMS, KASIMA and ECHAM5/MESSy1 simulations in the lower stratosphere using observations of Odin/SMR and ILAS/ILAS-II

2009 ◽  
Vol 9 (1) ◽  
pp. 1977-2020
Author(s):  
F. Khosrawi ◽  
R. Müller ◽  
M. H. Proffitt ◽  
R. Ruhnke ◽  
O. Kirner ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
General Circulation ◽  
Lower Stratosphere ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Lagrangian Model ◽  
Data Sets ◽  
Data Set ◽  
The Impact

Abstract. 1-year data sets of monthly averaged nitrous oxide (N2O) and ozone (O3) derived from satellite measurements were used as a tool for the evaluation of atmospheric photochemical models. Two 1-year data sets, one derived from the Improved Limb Atmospheric Spectrometer (ILAS and ILAS-II) and one from the Odin Sub-Millimetre Radiometer (Odin/SMR) were employed. Here, these data sets are used for the evaluation of two Chemical Transport Models (CTMs), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA) and the Chemical Lagrangian Model of the Stratosphere (CLaMS) as well as for one Chemistry-Climate Model (CCM), the atmospheric chemistry general circulation model ECHAM5/MESSy1 (E5M1) in the lower stratosphere with focus on the Northern Hemisphere. Since the Odin/SMR measurements cover the entire hemisphere, the evaluation is performed for the entire hemisphere as well as for the low latitudes, midlatitudes and high latitudes using the Odin/SMR 1-year data set as reference. To assess the impact of using different data sets for such an evaluation study we repeat the evaluation for the polar lower stratosphere using the ILAS/ILAS-II data set. Only small differences were found using ILAS/ILAS-II instead of Odin/SMR as a reference, thus, showing that the results are not influenced by the particular satellite data set used for the evaluation. The evaluation of CLaMS, KASIMA and E5M1 shows that all models are in good agreement with Odin/SMR and ILAS/ILAS-II. Differences are generally in the range of ±20%. Larger differences (up to −40%) are found in all models at 500±25 K for N2O mixing ratios greater than 200 ppb. Generally, the largest differences were found for the tropics and the lowest for the polar regions. However, an underestimation of polar winter ozone loss was found both in KASIMA and E5M1 both in the Northern and Southern Hemisphere.

scholarly journals The Influence of Temperature on Changes in the Distinguishing Features of the Usable Quality of Soybean Meal

2018 ◽  
Vol 1 (1) ◽  
pp. 377-383
Author(s):  
Beata Drzewieniecka ◽  
Jan Drzewieniecki ◽  
Miroslav Blatnický
Keyword(s):  
Fatty Acid ◽  
Soybean Meal ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Transport Processes ◽  
Influence Of Temperature ◽  
Influence Of Temperature On ◽  
The Impact ◽  
Distinguishing Features

Abstract Soybean meal is one of the fodder components. It is a by-product of the production of soybean oil. Soybean meal is a specific cargo due to changes that may occur in it during transport processes. These changes are subject to many distinguishing features of usable quality inter alia fat and fatty acid content. The temperature and size of the soybean meal particles are among the factors influencing the transformations. The article presents the results of research on soybean meal and its individual fractions and the impact of selected indicators on the quality changes of this cargo. The results depend on the conditions corresponding to those that occur during the storage, handling and transport processes. The dependencies between them have been determined. The performed research allowed to determine the type and scope of changes taking place in this cargo under the influence of temperature. The results of the study showed that as the temperature rises, the fatty acid content in the soybean meal decreased during storage for a given period of 30 days.

scholarly journals Impact of Lagrangian transport on lower-stratospheric transport timescales in a climate model

2020 ◽  
Vol 20 (23) ◽  
pp. 15227-15245
Author(s):  
Edward J. Charlesworth ◽  
Ann-Kristin Dugstad ◽  
Frauke Fritsch ◽  
Patrick Jöckel ◽  
Felix Plöger
Keyword(s):  
Atmospheric Chemistry ◽  
Large Scale ◽  
Climate Model ◽  
Polar Vortex ◽  
Transport Processes ◽  
Lagrangian Model ◽  
Trace Gas ◽  
Lagrangian Transport ◽  
Transport Barriers ◽  
The Impact

Abstract. We investigate the impact of model trace gas transport schemes on the representation of transport processes in the upper troposphere and lower stratosphere. Towards this end, the Chemical Lagrangian Model of the Stratosphere (CLaMS) was coupled to the ECHAM/MESSy Atmospheric Chemistry (EMAC) model and results from the two transport schemes (Lagrangian critical Lyapunov scheme and flux-form semi-Lagrangian, respectively) were compared. Advection in CLaMS was driven by the EMAC simulation winds, and thereby the only differences in transport between the two sets of results were caused by differences in the transport schemes. To analyze the timescales of large-scale transport, multiple tropical-surface-emitted tracer pulses were performed to calculate age of air spectra, while smaller-scale transport was analyzed via idealized, radioactively decaying tracers emitted in smaller regions (nine grid cells) within the stratosphere. The results show that stratospheric transport barriers are significantly stronger for Lagrangian EMAC-CLaMS transport due to reduced numerical diffusion. In particular, stronger tracer gradients emerge around the polar vortex, at the subtropical jets, and at the edge of the tropical pipe. Inside the polar vortex, the more diffusive EMAC flux-form semi-Lagrangian transport scheme results in a substantially higher amount of air with ages from 0 to 2 years (up to a factor of 5 higher). In the lowermost stratosphere, mean age of air is much smaller in EMAC, owing to stronger diffusive cross-tropopause transport. Conversely, EMAC-CLaMS shows a summertime lowermost stratosphere age inversion – a layer of older air residing below younger air (an “eave”). This pattern is caused by strong poleward transport above the subtropical jet and is entirely blurred by diffusive cross-tropopause transport in EMAC. Potential consequences from the choice of the transport scheme on chemistry–climate and geoengineering simulations are discussed.

scholarly journals A QBO-signal in mesospheric water vapor measurements at ALOMAR (69.29° N, 16.03° E) and in model calculations by LIMA over a solar cycle

2009 ◽  
Vol 9 (1) ◽  
pp. 883-903 ◽  
Author(s):  
G. R. Sonnemann ◽  
P. Hartogh ◽  
S. Li ◽  
M. Grygalashvyly ◽  
U. Berger
Keyword(s):  
Water Vapor ◽  
Solar Cycle ◽  
Middle Atmosphere ◽  
Transport Processes ◽  
Domain Model ◽  
Time Interval ◽  
High Latitudes ◽  
Model Calculations ◽  
The Real ◽  
Mixing Ratios

Abstract. Microwave water vapor measurements between 40 and 80 km over a solar cycle (1996–2006) were carried out in high latitudes at ALOMAR (69.29° N, 16.03° E), Norway. Three larger interuptions in the winters of 1996/97 and 2005/06, and from spring 2001 to spring 2002, a few smaller interruptions of monitoring occurred during this period. The observed year-to-year variability is not directly related to the solar activity. The analysis of the observations by the Fast Fourier Transform (FFT) method revealed peaks close to two years, particularly in the upper monitoring domain. Model calculations by means of the real date model LIMA, Leibniz-Institute Middle Atmosphere model, reflect essential patterns of the water vapor variation. The FFT-analysis of the calculated water vapor mixing ratios also showed peaks of around two years. The real period of the QBO during the monitoring period ranged quite close to two years within the time interval considered, with the exception of the years 2001/02 when the period was essentially longer. Although the QBO is a phenomenon occurring in the zonal wind of the tropical stratosphere, we suppose an influence of the QBO on the water vapor distribution of the mesosphere of high latitudes controlled by transport processes. A possible link could be given by the planetary wave activity triggered by the QBO.

scholarly journals From City- to Site-Dimension: Assessing the Urban Ecosystem Services of Different Types of Green Infrastructure

Land ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 150 ◽  
Author(s):  
Patrycia Brzoska ◽  
Aiga Spāģe
Keyword(s):  
Ecosystem Services ◽  
Urban Planning ◽  
Green Infrastructure ◽  
Green Roofs ◽  
Well Being ◽  
Urban Ecosystem ◽  
Primary Data ◽  
Small Scale ◽  
Small Scale Structures

Cities have a wide variety of green infrastructure types, such as parks and gardens. These structures can provide important ecosystem services (ES) with a major impact on human well-being. With respect to urban planning, special consideration must be given to such green infrastructure types when implementing measures to maintain and enhance the quality of life. Therefore, generating knowledge on the urban ES of differently scaled green infrastructure types is important. This systematic literature review provides an overview of existing studies which have explicitly investigated the urban ES of differently spatial-scaled green infrastructure types. By reviewing 76 publications, we confirm rising academic interest in this topic. The most frequently assessed urban ES belong to the category Regulating and Maintenance. Only a few have considered individual small structures such as green roofs or single gardens; green spaces are often aggregated into one, mostly city-wide, object of investigation, with resulting oversimplifications. Moreover, generalizing methods are mostly applied. Simultaneously, many studies have applied methods to evaluate location-specific primary data. More research is needed on small-scale structures, in particular to consider site-, and thus location-specific, parameters in order to successfully implement the ES concept into urban planning and to obtain realistic results for ES assessments.

Sign in / Sign up

Export Citation Format

Share Document