Rossby Wave Breaking and Transport between the Tropics and Extratropics above the Subtropical Jet

2013 ◽  
Vol 70 (2) ◽  
pp. 607-626 ◽  
Author(s):  
Cameron R. Homeyer ◽  
Kenneth P. Bowman
Keyword(s):  
Rossby Wave ◽  
Wave Breaking ◽  
Lower Stratosphere ◽  
Potential Temperature ◽  
Breaking Waves ◽  
Breaking Wave ◽  
Mean Flow ◽  
Rossby Wave Breaking ◽  
Subtropical Jet ◽  
The Tropics

Abstract Rossby wave breaking is an important mechanism for the two-way exchange of air between the tropical upper troposphere and lower stratosphere and the extratropical lower stratosphere. The authors present a 30-yr climatology (1981–2010) of anticyclonically and cyclonically sheared wave-breaking events along the boundary of the tropics in the 350–500-K potential temperature range from ECMWF Interim Re-Analysis (ERA-Interim). Lagrangian transport analyses show net equatorward transport from wave breaking near 380 K and poleward transport at altitudes below and above the 370–390-K layer. The finding of poleward transport at lower levels is in disagreement with previous studies and is shown to largely depend on the choice of tropical boundary. In addition, three distinct modes of transport for anticyclonic wave-breaking events are found near the tropical tropopause (380 K): poleward, equatorward, and symmetric. Transport associated with cyclonic wave-breaking events, however, is predominantly poleward. The three transport modes for anticyclonic wave breaking are associated with specific characteristics of the geometry of the mean flow. In particular, composite averages show that poleward transport is associated with a “split” subtropical jet where the jet on the upstream side of the breaking wave extends eastward and lies poleward and at lower altitudes of the subtropical jet on the downstream side, producing a substantial longitudinal overlap between the two jets. Equatorward transport is not associated with a split subtropical jet and is found immediately downstream of stationary anticyclones in the tropics, often associated with monsoon circulations. It is further shown that, in general, the transport direction of breaking waves is determined primarily by the relative positions of the jets.

Method for Identifying and Clustering Rossby Wave Breaking Events in the Northern Hemisphere

2021 ◽  
pp. 17-28
Author(s):  
A. V. Gochakov ◽  
◽  
O. Yu. Antokhina ◽  
V. N. Krupchatnikov ◽  
Yu. V. Martynova ◽  
...  
Keyword(s):  
Rossby Wave ◽  
Potential Vorticity ◽  
Wave Breaking ◽  
Large Scale ◽  
Method Development ◽  
Spatial Clustering ◽  
Potential Temperature ◽  
Reanalysis Data ◽  
Rossby Wave Breaking ◽  
Dynamic Phenomena

Many large-scale dynamic phenomena in the Earth’s atmosphere are associated with the processes of propagation and breaking of Rossby waves. A new method for identifying the Rossby wave breaking (RWB) is proposed. It is based on the detection of breakings centers by analyzing the shape of the contours of potential vorticity or temperature on quasimaterial surfaces: isentropic and iserthelic (surfaces of constant Ertel potential vorticity (PV)), with further RWB center clustering to larger regions. The method is applied to the set of constant PV levels (0.3 to 9.8 PVU with a step of 0.5 PVU) at the level of potential temperature of 350 K for 12:00 UTC. The ERA-Interim reanalysis data from 1979 to 2019 are used for the method development. The type of RWB (cyclonic/anticyclonic), its area and center are determined by analyzing the vortex geometry at each PV level for every day. The RWBs obtained at this stage are designated as elementary breakings. Density-Based Spatial Clustering of Applications with Noise algorithm (DBSCAN) was applied to all elementary breakings for each month. As a result, a graphic dataset describing locations and dynamics of RWBs for every month from 1979 to 2019 is formed. The RWB frequency is also evaluated for each longitude, taking into account the duration of each RWB and the number of levels involved, as well as the anomalies of these parameters.

scholarly journals Stratospheric intrusions induced by a Rossby Wave breaking and its interaction with the subtropical jet during PICO3 campaign

2005 ◽  
Vol 5 (5) ◽  
pp. 10301-10337
Author(s):  
A. Carré ◽  
F. Ravetta ◽  
J.-P. Cammas ◽  
P. Mascart ◽  
J. Duron ◽  
...  
Keyword(s):  
Rossby Wave ◽  
Vortex Core ◽  
Wave Breaking ◽  
Mesoscale Model ◽  
Rossby Wave Breaking ◽  
Airborne Measurements ◽  
Subtropical Jet ◽  
Stratospheric Intrusions

Abstract. This study documents several processes of stratosphere-troposphere transport (STT) in the subtropical region. A case study of the interaction between a Rossby Wave breaking over the Canary Islands and a subtropical vortex core situated further south is analysed with ozone airborne measurements (in-situ and Lidar). The investigation is conducted using a Reverse Domain Filling technique to reconstruct high-resolution potential vorticity fields with a Lagrangian approach and with simulations of a mesoscale model. Results show irreversible STT associated with tropopause folding, Rossby Wave Breaking and the filamentation of the subtropical vortex core.

scholarly journals The Shift of the Northern Node of the NAO and Cyclonic Rossby Wave Breaking

2012 ◽  
Vol 25 (22) ◽  
pp. 7973-7982 ◽  
Author(s):  
Yi-Hui Wang ◽  
Gudrun Magnusdottir
Keyword(s):  
Rossby Wave ◽  
Wave Breaking ◽  
Geographical Location ◽  
Mean Flow ◽  
Decadal Time Scale ◽  
Rossby Wave Breaking ◽  
The North ◽  
The Mean ◽  
The Difference ◽  
The North Atlantic Oscillation

Abstract Several studies have found an eastward shift in the northern node of the North Atlantic Oscillation (NAO) during the winters of 1978–97 compared to 1958–77. This study focuses on the connection between this shift of the northern node of the NAO and Rossby wave breaking (RWB) for the period 1958–97. It is found that the region of frequent cyclonic RWB underwent a northeastward shift at high latitudes in the latter 20-yr period. On a year-to-year basis, the cyclonic RWB region moves along a southwest–northeast (SW–NE)-directed axis. Both latitude and longitude of the winter maximum frequency of cyclonic RWB occurrence are positively correlated with the NAO index. To investigate the role of location of cyclonic RWB in influencing the NAO pattern, the geographical location of frequent cyclonic RWB is divided into two subdomains located along the SW–NE axis, to the south (SW domain) and east (NE domain) of Greenland. Two composites are assembled as one cyclonic RWB occurrence is detected in one of the two subdomains in 6-hourly instantaneous data. The forcing of the mean flow due to cyclonic RWB within individual subdomains is found to be locally restricted to where the breaking occurs, which is usually near the jet exit region and far removed from the jet core. The difference in the jet between the NE and SW composites resembles the difference in the mean jet between the 1978–97 and 1958–77 periods, which suggests that the change in cyclonic RWB occurrence in the two subdomains is associated with the wobbling of the jet on the decadal time scale.

scholarly journals Characteristics and Impacts of Extratropical Rossby Wave Breaking during the Atlantic Hurricane Season

2017 ◽  
Vol 30 (7) ◽  
pp. 2363-2379 ◽  
Author(s):  
Gan Zhang ◽  
Zhuo Wang ◽  
Melinda S. Peng ◽  
Gudrun Magnusdottir
Keyword(s):  
Rossby Wave ◽  
North Atlantic ◽  
Wave Breaking ◽  
Vertical Wind Shear ◽  
Breaking Wave ◽  
Western Basin ◽  
Western Atlantic ◽  
Rossby Wave Breaking ◽  
Atlantic Hurricane ◽  
Hurricane Season

This study investigates the characteristics of extratropical Rossby wave breaking (RWB) during the Atlantic hurricane season and its impacts on Atlantic tropical cyclone (TC) activity. It was found that RWB perturbs the wind and moisture fields throughout the troposphere in the vicinity of a breaking wave. When RWB occurs more frequently over the North Atlantic, the Atlantic main development region (MDR) is subject to stronger vertical wind shear and reduced tropospheric moisture; the basinwide TC counts are reduced, and TCs are generally less intense, have a shorter lifetime, and are less likely to make landfalls. A significant negative correlation was found between Atlantic TC activity and RWB occurrence during 1979–2013. The correlation is comparable to that with the MDR SST index and stronger than that with the Niño-3.4 index. Further analyses suggest that the variability of RWB occurrence in the western Atlantic is largely independent of that in the eastern Atlantic. The RWB occurrence in the western basin is more closely tied to the environmental variability of the tropical North Atlantic and is more likely to hinder TC intensification or reduce the TC lifetime because of its proximity to the central portion of TC tracks. Consequently, the basinwide TC counts and the accumulated cyclone energy have a strong correlation with western-basin RWB occurrence but only a moderate correlation with eastern-basin RWB occurrence. The results highlight the extratropical impacts on Atlantic TC activity and regional climate via RWB and provide new insights into the variability and predictability of TC activity.

scholarly journals The Influence of the Lower Stratosphere on Ridging Atlantic Ocean Anticyclones over South Africa

2018 ◽  
Vol 31 (15) ◽  
pp. 6175-6187 ◽  
Author(s):  
Thando Ndarana ◽  
Mary-Jane Bopape ◽  
Darryn Waugh ◽  
Liesl Dyson
Keyword(s):  
Atlantic Ocean ◽  
Rossby Wave ◽  
Wave Breaking ◽  
Large Scale ◽  
Lower Stratosphere ◽  
Reanalysis Data ◽  
Positive Anomaly ◽  
Pressure System ◽  
Rossby Wave Breaking ◽  
Vertical Coupling

The link between Rossby wave breaking and ridging Atlantic Ocean anticyclones in the South African domain is examined using NCEP–DOE AMIP-II reanalysis data. A simple composite analysis, which used the duration of ridging events as a basis of averaging, reveals that ridging anticyclones are coupled with Rossby wave breaking at levels higher than the dynamical tropopause. Lower-stratospheric PV anomalies extend to the surface, thus coupling the ridging highs with the lower stratosphere. The anomaly extending from the 70-hPa level to the surface contributes to a southward extension of the surface negative anomaly over the Namibian coast, which induces a cyclonic flow, causing the ridging anticyclone to take a bean-like shape. The surface positive anomaly induces the internal anticyclonic flow within the large-scale pressure system, causing the ridging end to break off and amalgamate with the Indian Ocean high pressure system. Lower-stratospheric Rossby wave breaking lasts for as long as the ridging process, suggesting that the former is critical to the longevity of the latter by maintaining and keeping the vertical coupling intact.

scholarly journals Secondary maxima in ozone profiles

2004 ◽  
Vol 4 (2) ◽  
pp. 1791-1816
Author(s):  
R. Lemoine
Keyword(s):  
Rossby Wave ◽  
Ozone Concentration ◽  
Wave Breaking ◽  
Total Ozone ◽  
Lower Stratosphere ◽  
Rossby Wave Breaking ◽  
Ozone Distribution ◽  
Ozone Trends ◽  
Differential Advection ◽  
Ozone Column

Abstract. Ozone profiles from balloon soundings as well as SAGE II ozone profiles were used to detect anomalous large ozone concentrations of ozone in the lower stratosphere. These secondary ozone maxima are found to be the result of differential advection of ozone-poor and ozone-rich air associated with Rossby wave breaking events. The frequency and intensity of secondary ozone maxima and their geographical distribution is presented. The occurrence and amplitude of ozone secondary maxima is related to ozone trends in the total ozone column and in the lower stratosphere ozone concentration at Uccle and can be used as a measure of the influence of atmospheric circulation on the ozone distribution at mid-latitudes.

scholarly journals Blocking and Rossby Wave Breaking on the Dynamical Tropopause in the Southern Hemisphere

2007 ◽  
Vol 64 (8) ◽  
pp. 2881-2898 ◽  
Author(s):  
P. Berrisford ◽  
B. J. Hoskins ◽  
E. Tyrlis
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Rossby Wave ◽  
Wave Breaking ◽  
Large Scale ◽  
Potential Temperature ◽  
Upper Troposphere ◽  
Rossby Wave Breaking ◽  
The Pacific ◽  
Westerly Flow

Rossby wave breaking on the dynamical tropopause in the Southern Hemisphere (the −2-PVU surface) is investigated using the ERA-40 dataset. The indication of wave breaking is based on reversal in the meridional gradient of potential temperature, and persistent large-scale wave breaking is taken as a strong indication that blocking may be present. Blocking in the midlatitudes is found to occur predominantly during wintertime in the Pacific and is most vigorous in the east Pacific, while during summertime, the frequency of blocking weakens and its extent becomes confined to the west Pacific. The interannual variability of blocking is found to be high. Wave breaking occurs most frequently on the poleward side of the polar jet and has some, but not all, of the signatures of blocking, so it is referred to as high-latitude blocking. In general, cyclonic wave breaking occurs on the poleward side of the polar jet, otherwise anticyclonic breaking occurs. However, at least in wintertime, wave breaking in the New Zealand/west to mid-Pacific sector between the polar and subtropical jets is a mixture between cyclonic and anticyclonic types. Together, episodes of wave breaking and enhanced westerly flow describe much of the variability in the seasonal Antarctic Oscillation (AnO) index and give a synoptic manifestation of it with a focus on the date line and Indian Ocean that is in agreement with the centers of action for the AnO. During summertime, anticyclonic wave breaking in the upper troposphere is also to be found near 30°S in both the Pacific and Atlantic, and appears to be associated with Rossby waves propagating into the subtropics from the New Zealand region.

scholarly journals A New Perspective toward Cataloging Northern Hemisphere Rossby Wave Breaking on the Dynamic Tropopause

2019 ◽  
Vol 147 (2) ◽  
pp. 409-431 ◽  
Author(s):  
Kevin A. Bowley ◽  
John R. Gyakum ◽  
Eyad H. Atallah
Keyword(s):  
Rossby Wave ◽  
North Pacific ◽  
Wave Breaking ◽  
Potential Temperature ◽  
Low Frequency ◽  
The Arctic ◽  
Rossby Wave Breaking ◽  
Modes Of Variability ◽  
The North ◽  
The North Atlantic Oscillation

Abstract Rossby wave breaking (RWB) events are a common feature on the dynamic tropopause and act to modulate synoptic-scale jet dynamics. These events are characterized on the dynamic tropopause by an irreversible overturning of isentropes and are coupled to troposphere-deep vertical motions and geopotential height anomalies. Prior climatologies have focused on the poleward streamer, the equatorward streamer, or the reversal in potential temperature gradient between the streamers, resulting in differences in the frequencies of RWB. Here, a new approach toward cataloging these events that captures both streamers is applied to the National Centers for Environmental Prediction Reanalysis-2 dataset for 1979–2011. Anticyclonic RWB (AWB) events are found to be nearly twice as frequent as cyclonic RWB (CWB) events. Seasonal decompositions of the annual mean find AWB to be most common in summer (40% occurrence), which is likely due to the Asian monsoon, while CWB is most frequent in winter (22.5%) and is likely due to the equatorward shift in mean baroclinicity. Trends in RWB from 1980 to 2010 illustrate a westward shift in North Pacific AWB during winter and summer (up to 0.4% yr−1), while CWB in the North Pacific increases in winter and spring (up to 0.2% yr−1). These changes are hypothesized to be associated with localized changes in the two-way interaction between the jet and RWB. The interannual variability of AWB and CWB is also explored, and a notable modality to the frequency of RWB is found that may be attributable to known low-frequency modes of variability including the Arctic Oscillation, the North Atlantic Oscillation, and the Pacific–North American pattern.

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