scholarly journals High-ozone layers in the middle and upper troposphere above Central Europe: potential import from the stratosphere along the subtropical jet stream

2010 ◽  
Vol 10 (12) ◽  
pp. 30473-30537
Author(s):  
T. Trickl ◽  
N. Bärtsch-Ritter ◽  
H. Eisele ◽  
M. Furger ◽  
R. Mücke ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Transport Model ◽  
Dispersion Model ◽  
Warm Season ◽  
Particle Dispersion ◽  
Jet Stream ◽  
Upper Troposphere ◽  
North West ◽  
Subtropical Jet Stream ◽  
Subtropical Jet

Abstract. Specific very dry high-ozone layers have been repeatedly observed in the middle and upper troposphere with the ozone lidar in Garmisch-Partenkirchen (Germany), starting roughly two days after the onset of high-pressure periods during the warm season. These episodes, previously not understood, were recently analysed based on extended simulations with the FLEXPART particle dispersion model and jet-stream analyses with the LAGRANTO transport model. The model results indicate import from the stratosphere along the subtropical jet stream over the Pacific Ocean and all the way back to the Atlantic Ocean, in some cases mixed with stratospheric air from intrusions over the North-West Pacific Ocean. Occasionally, also air from the boundary layers of East Asia and North America was admixed. The analysis suggests that stratospheric influence is the most important factor for the increase in ozone and is related to a rather shallow transfer of air from the stratosphere into the rapid upper-and mid-tropospheric air streams observed with the lidar. The in part considerable vertical and temporal extent of these layers and peak ozone mixing ratios between 80 and 150 \\unit{ppb} suggest this to be an important mechanism for stratosphere-to-troposphere transport.

scholarly journals High-ozone layers in the middle and upper troposphere above Central Europe: potential import from the stratosphere along the subtropical jet stream

2011 ◽  
Vol 11 (17) ◽  
pp. 9343-9366 ◽  
Author(s):  
T. Trickl ◽  
N. Bärtsch-Ritter ◽  
H. Eisele ◽  
M. Furger ◽  
R. Mücke ◽  
...  
Keyword(s):  
Transport Model ◽  
Dispersion Model ◽  
Warm Season ◽  
Particle Dispersion ◽  
Jet Stream ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Subtropical Jet Stream ◽  
Subtropical Jet ◽  
The Pacific

Abstract. Specific very dry high-ozone layers, starting roughly two days after the onset of high-pressure periods during the warm season, have been reproducibly observed in the middle and upper troposphere with the ozone lidar in Garmisch-Partenkirchen (Germany). These episodes, previously not understood, were recently analysed based on extending backward simulations with the FLEXPART particle dispersion model to as many as twenty days and on jet-stream analyses including calculations with the LAGRANTO transport model. In all six cases analysed the model results indicate ozone import from the stratosphere on an extremely long path along the subtropical jet stream over the Pacific Ocean, Asia and, in part, all the way back to the Atlantic Ocean. The analysis suggests that stratospheric influence is the most important factor for the increase in ozone and is related to rather shallow transfer of air from the stratosphere into the upper- and mid-tropospheric air streams observed with the lidar. Contributions from the boundary layers of East Asia and North America are just occasionally present, in one case documented by a very dense aerosol plume from the Asian deserts. The considerable vertical and temporal extent of many of these layers and peak ozone mixing ratios between 80 and 150 ppb suggest that the observations are related to an important mechanism for stratosphere-to-troposphere transport (STT) and also confirm the model predictions of pronounced and persistent STT along the subtropical jet stream.

scholarly journals High-ozone layers in the middle and upper troposphere above Central Europe: strong import from the stratosphere over the Pacific Ocean

2009 ◽  
Vol 9 (1) ◽  
pp. 3113-3166 ◽  
Author(s):  
T. Trickl ◽  
N. Bärtsch-Ritter ◽  
H. Eisele ◽  
M. Furger ◽  
R. Mücke ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Dispersion Model ◽  
Warm Season ◽  
Particle Dispersion ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Trajectory Calculations ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Air Streams

Abstract. Very dry high-ozone layers have been repeatedly observed with the ozone lidar in Garmisch-Partenkirchen (Germany) starting one or two days after the onset of high-pressure periods during the warm season. These episodes have been analysed by trajectory calculations and extended simulations with the FLEXPART particle dispersion model. Mixed contributions from the stratosphere over the Pacific Ocean and the boundary layers of East Asia and North America were found. The stratospheric influence is mostly dominating and caused by a rather shallow transfer from the stratosphere into these rapid upper- and mid-tropospheric air streams. The considerable vertical extent of these layers and peak ozone mixing ratios between 80 and 150 ppb suggest an important mechanism for stratosphere-to-troposphere transport.

scholarly journals Ozone-enhanced layers in the troposphere over the equatorial Pacific Ocean and the influence of transport of midlatitude UT/LS air

2007 ◽  
Vol 7 (6) ◽  
pp. 17179-17211
Author(s):  
H. Hayashi ◽  
K. Kita ◽  
S. Taguchi
Keyword(s):  
Pacific Ocean ◽  
American Samoa ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Air Masses ◽  
Upper Troposphere ◽  
Narrow Region ◽  
Subtropical Jet Stream ◽  
Subtropical Jet ◽  
Yearly Average

Abstract. Occurrence of ozone (O3)-enhanced layers in the troposphere over the equatorial Pacific Ocean and their seasonal variation were investigated based on ozonesonde data obtained at three Southern Hemisphere ADditional OZonesondes (SHADOZ) sites, Watukosek, American Samoa and San Cristobal, for 6 years between 1998 and 2003. O3-enhanced layers were found in about 50% of observed O3 profiles at the three sites on yearly average. The formation processes of O3-enhanced layers were investigated by meteorological analyses including backward trajectories. On numerous occasions, O3-enhanced layers resulted from the transport of air masses affected by biomass burning. The contribution of this process was about 30% at San Cristobal during the periods from February to March and from August to September, while it was relatively low, about 10%, at Watukosek and Samoa. A significant number of the O3-enhanced layers were attributed to the transport of midlatitude upper-troposphere and lower-stratosphere (UT/LS) air. Meteorological analyses indicated that these layers originated from equatorward and downward transport of the midlatitude UT/LS air masses through a narrow region between high- and low-pressure systems around the subtropical jet stream. This process accounted for more than 40% at Watukosek between May and December, about 60% or more at Samoa all year around, and about 40% at San Cristobal between November and March, indicating that it was important for O3 budget over the equatorial Pacific Ocean.

scholarly journals Ozone-enhanced layers in the troposphere over the equatorial Pacific Ocean and the influence of transport of midlatitude UT/LS air

2008 ◽  
Vol 8 (10) ◽  
pp. 2609-2621 ◽  
Author(s):  
H. Hayashi ◽  
K. Kita ◽  
S. Taguchi
Keyword(s):  
Pacific Ocean ◽  
American Samoa ◽  
Equatorial Pacific ◽  
Equatorial Pacific Ocean ◽  
Air Masses ◽  
Upper Troposphere ◽  
Narrow Region ◽  
Subtropical Jet Stream ◽  
Subtropical Jet ◽  
Yearly Average

Abstract. Occurrence of ozone (O3)-enhanced layers in the troposphere over the equatorial Pacific Ocean and their seasonal variation were investigated based on ozonesonde data obtained at three Southern Hemisphere ADditional OZonesondes (SHADOZ) sites, Watukosek, American Samoa and San Cristobal, for 6 years between 1998 and 2003. O3-enhanced layers were found in about 50% of observed O3 profiles at the three sites. The formation processes of O3-enhanced layers were investigated by meteorological analyses including backward trajectories. On numerous occasions, O3-enhanced layers resulted from the transport of air masses affected by biomass burning. The contribution of this process was about 30% at San Cristobal during the periods from February to March and from August to September, while it was relatively low, about 10%, at Watukosek and Samoa. A significant number of the O3-enhanced layers were attributed to the transport of midlatitude upper-troposphere and lower-stratosphere (UT/LS) air. Meteorological analyses indicated that these layers originated from equatorward and downward transport of the midlatitude UT/LS air masses through a narrow region between high- and low-pressure systems around the subtropical jet stream. This process accounted for 50–80% at Watukosek between May and December, about 80% at Samoa on yearly average, and 40–70% at San Cristobal between November and March, indicating that it was important for O3 budget over the equatorial Pacific Ocean.

scholarly journals Characteristics of mid-latitude planetary waves in the lower atmosphere derived from radiosonde data

2012 ◽  
Vol 30 (10) ◽  
pp. 1463-1477 ◽  
Author(s):  
R. Wang ◽  
S. D. Zhang ◽  
H. G. Yang ◽  
K. M. Huang
Keyword(s):  
Standing Wave ◽  
Zonal Wind ◽  
Lower Stratosphere ◽  
Radiosonde Data ◽  
Wind Component ◽  
Jet Stream ◽  
Fort Worth ◽  
Vertical Wavelength ◽  
Subtropical Jet Stream ◽  
Subtropical Jet

Abstract. The activities of mid-latitude planetary waves (PWs) in the troposphere and lower stratosphere (TLS) are presented by using the radiosonde data from 2000 to 2004 over four American stations (Miramar Nas, 32.9° N, 117.2° W; Santa Teresa, 31.9° N, 106.7° W; Fort Worth, 32.8° N, 97.3° W; and Birmingham, 33.1° N, 86.7° W) and one Chinese station (Wuhan, 30.5° N, 114.4° E). Statistically, strong PWs mainly appear around subtropical jet stream in the troposphere and lower stratosphere. In the troposphere, the activities of the mid-latitude PWs are strong around the centre of the subtropical jet stream in winter and become small near the tropopause, which indicates that the subtropical jet stream may strengthen the propagation of PWs or even be one of the PW excitation sources. Among the three disturbance components of temperature, zonal and meridional winds, PWs at Wuhan are stronger in the temperature component, but weaker in the zonal wind component than at the other four American stations. While in the meridional wind component, the strengths of PW spectral amplitudes at the four American stations decrease from west to east, and their amplitudes are all larger than that of Wuhan. However, the PWs are much weaker in the stratosphere and only the lower frequency parts remain. The amplitudes of the PWs in the stratosphere increase with height and are strong in winter with the zonal wind component being the strongest. Using the refractive index, we found that whether the PWs could propagate upward to the stratosphere depends on the thickness of the tropopause reflection layer. In the case study of the 2000/2001 winter, it is observed that the quasi 16-day wave in the troposphere is a quasi standing wave in the vertical direction and propagates upward slowly with vertical wavelength greater than 24 km in the meridional component. It propagates eastward with the zonal numbers between 5 and 8, and the quasi 16-day wave at Wuhan is probably the same quasi 16-day wave at the three American stations (Miramar Nas, Santa Teresa and Fort Worth), which propagates steadily along the latitude. The quasi 16-day wave in the stratosphere is also a standing wave with vertical wavelength larger than 10 km in the zonal wind component, and it is westward with the zonal number 1–2. However, the quasi 16-day wave in the stratosphere may not come from the troposphere because of the different concurrent times, propagation directions and velocities. By using the global dataset of NCEP/NCAR reanalysis data, the zonal propagation parameters of 16-day waves in the troposphere and stratosphere are calculated. It is found that the tropospheric 16-day wave propagates eastward with the zonal number 6, while the stratospheric 16-day wave propagates westward with the zonal number 2, which matches well with the results of radiosonde data.

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