scholarly journals The dynamical impact of Rossby wave breaking upon UK PM<sub>10</sub> concentration

2017 ◽  
Vol 17 (2) ◽  
pp. 867-881 ◽  
Author(s):  
Christopher P. Webber ◽  
Helen F. Dacre ◽  
William J. Collins ◽  
Giacomo Masato
Keyword(s):  
Rossby Wave ◽  
Wave Breaking ◽  
Ground Level ◽  
Reanalysis Data ◽  
Synoptic Scale ◽  
Urban Background ◽  
Air Masses ◽  
Rossby Wave Breaking ◽  
Coarse Particulate Matter ◽  
The Uk

Abstract. Coarse particulate matter (PM10) has long been understood to be hazardous to human health, with mortality rates increasing as a result of raised ground level concentrations. We explore the influence of synoptic-scale meteorology on daily mean observed PM10 concentration ([PM10]) using Rossby wave breaking (RWB). Meteorological reanalysis data for the winter months (DJF) between January 1999 and December 2008 and observed PM10 data for three urban background UK (Midland) sites were analysed. Three RWB diagnostics were used to identify RWB that had significant influence on UK Midland PM10. RWB events were classified according to whether the RWB was cyclonic or anticyclonic in its direction of breaking and whether the RWB event was influenced more by poleward or equatorial air masses. We find that there is a strong link between RWB events and UK [PM10]. Significant increases (p  <  0.01) in UK [PM10] were seen 1 day following RWB occurring in spatially constrained northeast Atlantic–European regions. Analysis into episodic PM10 exceedance events shows increased probability of [PM10] exceedance associated with all RWB subsets. The greatest probability of exceeding the UK [PM10] threshold was associated with cyclonic RWB preceded by anticyclonic RWB forming an Ω block synoptic pattern. This mechanism suggests an easterly advection of European PM10 followed by prolonged stagnant conditions within the UK and led to an almost threefold increase in the probability of the UK Midlands exceeding a hazardous [PM10] threshold (0.383), when compared to days where no RWB was detected (0.129).

scholarly journals The Dynamical Impact of Rossby Wave Breaking upon UK PM10 Concentration

2016 ◽  
Author(s):  
C. P. Webber ◽  
H. F. Dacre ◽  
W. J. Collins ◽  
G. Masato
Keyword(s):  
Rossby Wave ◽  
Wave Breaking ◽  
Ground Level ◽  
Analysis Data ◽  
Pm10 Concentration ◽  
Synoptic Scale ◽  
Urban Background ◽  
Air Masses ◽  
Rossby Wave Breaking ◽  
Coarse Particulate Matter

Abstract. Coarse particulate matter (PM10) has long been understood to be hazardous to human health with mortality rates increasing as a result of raised ground level concentrations. We explore the influence of synoptic scale meteorology on observed PM10 concentration ([PM10]) using Rossby Wave Breaking (RWB). Meteorological re-analysis data for the winter months (DJF) between January 1999 and December 2008 and observed PM10 data for three urban background UK (Midland) sites, were analysed. Three RWB diagnostics were used to identify RWB that had significant influence on UK Midland PM10. RWB events were classified according to whether the RWB was cyclonic or anticyclonic in its direction of breaking and whether the RWB event was influenced more by poleward or equatorial air masses. We find that there is a strong link between RWB events and UK [PM10]. Significant increases (p 

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.

3-D tomographic observations of Rossby wave breaking over the Northern Atlantic during the WISE aircraft campaign in 2017

2021 ◽  
Author(s):  
Lukas Krasauskas ◽  
Jörn Ungermann ◽  
Peter Preusse ◽  
Felix Friedl-Vallon ◽  
Andreas Zahn ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Water Vapour ◽  
Rossby Wave ◽  
Wave Breaking ◽  
Thin Filament ◽  
Small Scale ◽  
Data Sets ◽  
Mixing Processes ◽  
Air Masses ◽  
Rossby Wave Breaking

&lt;p&gt;We present measurements of ozone, water vapour and nitric acid in the upper troposphere/lower stratosphere (UTLS) over North Atlantic and Europe. The measurements were acquired with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the Wave Driven Isentropic Exchange (WISE) campaign in October 2017. GLORIA is an airborne limb imager capable of acquiring both 2-D data sets (curtains along the flight path) and, when the carrier aircraft is flying around the observed air mass, spatially highly resolved 3-D tomographic data. We show a case study of a Rossby wave (RW) breaking event observed during two subsequent flights two days apart. RW breaking is known to steepen tracer gradients and facilitate stratosphere-troposphere exchange (STE). Our measurements reveal complex spatial structures in stratospheric tracers (ozone and nitric acid) with multiple vertically stacked filaments. Backward trajectory analysis is used to demonstrate that these features are related to several previous Rossby wave breaking events and that the small-scale structure of the UTLS in the Rossby wave breaking region, which is otherwise very hard to observe, can be understood as stirring and mixing of air masses of tropospheric and stratospheric origin. It is also shown that a strong nitric acid enhancement observed just above the tropopause is likely a result of NO&lt;sub&gt;x&lt;/sub&gt; production by lightning activity. The measurements showed signatures of enhanced mixing between stratospheric and tropospheric air near the polar jet with some transport of water vapour into the stratosphere. Some of the air masses seen in 3-D data were encountered again two days later, stretched to very thin filament (horizontal thickness down to 30&amp;#8201;km at some altitudes) rich in stratospheric tracers. This repeated measurement allowed us to directly observe and analyse the progress of mixing processes in a thin filament over two days. Our results provide direct insight into small-scale dynamics of the UTLS in the Rossby wave breaking region, witch is of great importance to understanding STE and poleward transport in the UTLS.&lt;/p&gt;

scholarly journals A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

2021 ◽  
Author(s):  
Andries Jan De Vries
Keyword(s):  
Rossby Wave ◽  
Extreme Precipitation ◽  
Wave Breaking ◽  
Moisture Transport ◽  
Synoptic Scale ◽  
Rossby Wave Breaking ◽  
Extreme Precipitation Events ◽  
The World ◽  
Upper Level ◽  
Precipitation Events

&lt;p&gt;Extreme precipitation events (EPEs) frequently cause flooding with dramatic socioeconomic impacts in many parts of the world. Previous studies considered two synoptic-scale processes, Rossby wave breaking and intense moisture transport, typically in isolation, and their linkage to such EPEs in several regions. This study presents for the first time a global and systematic climatological analysis of these two synoptic-scale processes, in tandem and in isolation, for the occurrence of EPEs. To this end, we use 40-year ERA-Interim reanalysis data (1979-2018) and apply object-based identification methods for (i) daily EPEs, (ii) stratospheric potential vorticity (PV) streamers as indicators of Rossby wave breaking, and (iii) structures of high vertically integrated horizontal water vapor transport (IVT). First, the importance of these two synoptic-scale processes is demonstrated by case studies of previously documented flood events that inflicted catastrophic impacts in different parts of the world. Next, a climatological quantification shows that Rossby wave breaking is associated with &gt; 90 % of EPEs near high topography and over the Mediterranean, whereas intense moisture transport is linked to &gt; 95 % of EPEs over many coastal zones, consistent with findings of atmospheric river-related studies. Combined Rossby wave breaking and intense moisture transport contributes up to 70 % of EPEs in several subtropical and extratropical regions, including (semi)arid desert regions where tropical-extratropical interactions are of key importance for (heavy) rainfall. A detailed analysis shows that five categories with different combinations of wave breaking and intense moisture transport can reflect a large range of EPE-related weather systems across various climate zones. Odds ratios of EPEs linked to the two synoptic-scale processes suggest that intense moisture transport is stronger associated with the occurrence of EPEs than wave breaking. Furthermore, the relationship between the PV and IVT characteristics and the precipitation volumes shows that the depth of the wave breaking and moisture transport intensity are intimately connected with the extreme precipitation severity. Finally, composites reveal that subtropical and extratropical EPEs, linked to Rossby wave breaking, go along with the formation of upper-level troughs and cyclogenetic processes near the surface downstream, reduced static stability beneath the upper-level forcing (only over water), and dynamical lifting ahead (over water and land). This study concludes with a concept that reconciles well-established meteorological principles with the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events. The findings of this study may contribute to an improved understanding of the atmospheric processes that lead to EPEs, and may find application in climatic studies on extreme precipitation changes in a warming climate.&lt;/p&gt;

scholarly journals The Role of Dynamic Tropopause Rossby Wave Breaking for Synoptic-Scale Buildups in Northern Hemisphere Zonal Available Potential Energy

2019 ◽  
Vol 147 (2) ◽  
pp. 433-455 ◽  
Author(s):  
Kevin A. Bowley ◽  
John R. Gyakum ◽  
Eyad H. Atallah
Keyword(s):  
Potential Energy ◽  
Northern Hemisphere ◽  
Rossby Wave ◽  
North Pacific ◽  
Wave Breaking ◽  
Synoptic Scale ◽  
Rossby Wave Breaking ◽  
The North ◽  
The North Pacific

Abstract Zonal available potential energy AZ measures the magnitude of meridional temperature gradients and static stability of a domain. Here, the role of Northern Hemisphere dynamic tropopause (2.0-PVU surface) Rossby wave breaking (RWB) in supporting an environment facilitating buildups of AZ on synoptic time scales (3–10 days) is examined. RWB occurs when the phase speed of a Rossby wave slows to the advective speed of the atmosphere, resulting in a cyclonic or anticyclonic RWB event (CWB and AWB, respectively). These events have robust dynamic and thermodynamic feedbacks through the depth of the troposphere that can modulate AZ. Significant synoptic-scale buildups in AZ and RWB events are identified from the National Centers for Environmental Prediction Reanalysis-2 dataset from 1979 to 2011 for 20°–85°N. Anomalies in AWB and CWB are assessed seasonally for buildup periods of AZ. Positive anomalies in AWB and negative anomalies in CWB are found for most AZ buildup periods in the North Pacific and North Atlantic basins and attributed to localized poleward shifts in the jet stream. Less frequent west–east dipoles in wave breaking anomalies for each basin are attributed to elongated and contracted regional jet exit regions. Finally, an analysis of long-duration AWB events for winter AZ buildup periods to an anomalously high AZ state is performed using a quasi-Lagrangian grid-shifting technique. North Pacific AWB events are shown to diabatically intensify the North Pacific jet exit region (increasing Northern Hemisphere AZ) through latent heating equatorward of the jet exit and radiative and evaporative cooling poleward of the jet exit.

A Seasonal Climatology of Rossby Wave Breaking in the 320–2000-K Layer

2007 ◽  
Vol 64 (6) ◽  
pp. 1922-1940 ◽  
Author(s):  
Matthew H. Hitchman ◽  
Amihan S. Huesmann
Keyword(s):  
Rossby Wave ◽  
Wave Breaking ◽  
Reanalysis Data ◽  
Polar Night ◽  
Rossby Wave Breaking ◽  
Polar Stratosphere ◽  
Differential Advection ◽  
Shed Light ◽  
Pv Gradient ◽  
Westerly Jets

Differential advection in Rossby waves can lead to potential vorticity (PV; P) contours on isentropic surfaces folding over in latitude (Py < 0) in a process called Rossby wave breaking (RWB). Exploring the properties of RWB may shed light on underlying dynamics and enable quantification of irreversible transport. A seasonal climatology of Py and RWB statistics is presented for the 320–850-K layer using NCEP reanalysis data during 1979–2005 and for the 320–2000-K layer using the Met Office (UKMO) data during 1991–2003. A primary goal is to depict the spatial extent and seasonality of RWB maxima. This analysis shows seven distinct RWB regimes: poleward and equatorward of the subtropical westerly jets, poleward and equatorward of the stratospheric polar night jets, flanking the equator in the stratosphere and mesosphere, equatorward of subtropical monsoon anticyclones, and the summertime polar stratosphere. A striking PV gradient maximum exists at the equator throughout the layer 360–2000 K, flanked by subtropical RWB maxima, integral components of the Lagrangian cross-equatorial flow. Strong RWB occurs in the polar night vortex where β is small. Over the summer pole, strong poleward RWB associated with synoptic waves decays into small amplitude motions in the upper stratosphere, where heating gradients cause Py < 0. The seven spatial regimes are linked to three different dynamical causes of reversals: wave breaking associated with westerly jets, a combined barotropic/inertial instability in cross-equatorial flow, and on the periphery of monsoon anticyclones.

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 3-D tomographic observations of Rossby wave breaking over the North Atlantic during the WISE aircraft campaign in 2017

2021 ◽  
Vol 21 (13) ◽  
pp. 10249-10272
Author(s):  
Lukas Krasauskas ◽  
Jörn Ungermann ◽  
Peter Preusse ◽  
Felix Friedl-Vallon ◽  
Andreas Zahn ◽  
...  
Keyword(s):  
Nitric Acid ◽  
Water Vapour ◽  
Rossby Wave ◽  
North Atlantic ◽  
Wave Breaking ◽  
Thin Filament ◽  
Small Scale ◽  
Mixing Processes ◽  
Air Masses ◽  
Rossby Wave Breaking

Abstract. This paper presents measurements of ozone, water vapour and nitric acid (HNO3) in the upper troposphere/lower stratosphere (UTLS) over North Atlantic and Europe. The measurements were acquired with the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) during the Wave Driven Isentropic Exchange (WISE) campaign in October 2017. GLORIA is an airborne limb imager capable of acquiring both 2-D data sets (curtains along the flight path) and, when the carrier aircraft is flying around the observed air mass, spatially highly resolved 3-D tomographic data. Here, we present a case study of a Rossby wave (RW) breaking event observed during two subsequent flights 2 d apart. RW breaking is known to steepen tracer gradients and facilitate stratosphere–troposphere exchange (STE). Our measurements reveal complex spatial structures in stratospheric tracers (ozone and nitric acid) with multiple vertically stacked filaments. Backward-trajectory analysis is used to demonstrate that these features are related to several previous Rossby wave breaking events and that the small-scale structure of the UTLS in the Rossby wave breaking region, which is otherwise very hard to observe, can be understood as stirring and mixing of air masses of tropospheric and stratospheric origin. It is also shown that a strong nitric acid enhancement observed just above the tropopause is likely a result of NOx production by lightning activity. The measurements showed signatures of enhanced mixing between stratospheric and tropospheric air near the polar jet with some transport of water vapour into the stratosphere. Some of the air masses seen in 3-D data were encountered again 2 d later, stretched to very thin filament (horizontal thickness down to 30 km at some altitudes) rich in stratospheric tracers. This repeated measurement allowed us to directly observe and analyse the progress of mixing processes in a thin filament over 2 d. Our results provide direct insight into small-scale dynamics of the UTLS in the Rossby wave breaking region, which is of great importance to understanding STE and poleward transport in the UTLS.

scholarly journals A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

2020 ◽  
Author(s):  
Andries Jan De Vries
Keyword(s):  
Rossby Wave ◽  
Extreme Precipitation ◽  
Wave Breaking ◽  
Moisture Transport ◽  
Synoptic Scale ◽  
Rossby Wave Breaking ◽  
Extreme Precipitation Events ◽  
Upper Level ◽  
High Topography ◽  
Precipitation Events

Abstract. Extreme precipitation events (EPEs) cause frequently flooding with dramatic socioeconomic impacts in many parts of the world. Previous studies considered two synoptic-scale processes, Rossby wave breaking and intense moisture transport, typically in isolation, and their linkage to such EPEs in several regions. This study presents for the first time a global and systematic climatological analysis of these two synoptic-scale processes, in tandem and in isolation, for the occurrence of EPEs. To this end, we use 40-year ERA-Interim reanalysis data (1979–2018) and apply object-based identification methods for (i) daily EPEs, (ii) stratospheric potential vorticity (PV) streamers as indicators of Rossby wave breaking, and (iii) structures of high vertically integrated horizontal water vapor transport (IVT). First, the importance of these two processes is demonstrated by case studies of previously documented flood events that inflicted catastrophic impacts in different parts of the world. Next, a climatological quantification shows that Rossby wave breaking is associated with > 90 % of EPEs near high topography and over the Mediterranean, intense moisture transport is linked to > 90 % of EPEs over many coastal zones, and their combined occurrence contributes to > 70 % of EPEs in several subtropical and extratropical regions. A more detailed analysis shows that a majority of EPEs associated with (1) only Rossby wave breaking are confined to higher-latitude regions that are deprived from remote moisture supplies by high topography and deserts, (2) only intense moisture transport are found circumglobally at the outer tropics, associated with tropical cyclones, tropical easterly waves, and monsoon lows, (3) combined Rossby wave breaking and intense moisture transport dominate a large part of the globe, in particular over dry subtropical regions where tropical-extratropical interactions are of key relevance, (4) remote, far upstream Rossby wave breaking and intense moisture transport occur over mountainous extratropical west coasts, reminiscent of landfalling atmospheric rivers, and (5) neither of the two synoptic-scale processes are concentrated over the inner tropics and high topography at lower latitudes, where EPEs arise under the influence of local forcing. Accordingly, different combinations of wave breaking and intense moisture transport can reflect a large range of weather systems with relevance to EPEs across various climate zones. Furthermore, the relationship between the PV and IVT characteristics and the precipitation volumes shows that the strength of the wave breaking and moisture transport intensity are intimately connected with the extreme precipitation severity. Finally, composites reveal that subtropical and extratropical EPEs, linked to Rossby wave breaking, go along with the formation of upper-level troughs and cyclogenetic processes near the surface downstream, reduced static stability beneath the upper-level forcing (only over water), and dynamical lifting ahead (over water and land). This study concludes with a concept that reconciles well-established meteorological principles with the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events. The findings of this study may contribute to an improved understanding of the atmospheric processes that lead to EPEs, and may find application in climatic studies on extreme precipitation changes in a warming climate.

North Atlantic Summertime Anticyclonic Rossby Wave Breaking: Climatology, Impacts, and Connections to the Pacific Decadal Oscillation

2018 ◽  
Vol 32 (2) ◽  
pp. 485-500 ◽  
Author(s):  
Breanna L. Zavadoff ◽  
Ben P. Kirtman
Keyword(s):  
Rossby Wave ◽  
North Atlantic ◽  
Pacific Decadal Oscillation ◽  
Wave Breaking ◽  
Reanalysis Data ◽  
Tropical Cyclogenesis ◽  
Rossby Wave Breaking ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation

Abstract Anticyclonic Rossby wave breaking (RWB) is characterized by the rapid and irreversible deformation of potential vorticity (PV) contours on isentropic surfaces manifesting as a pair of meridionally elongated high- and low-PV tongues that transport extratropical stratospheric air equatorward and tropical tropospheric air poleward, respectively. Previous studies have noted connections between different types of RWB and the modulation of localized atmospheric phenomena such as the North Atlantic Oscillation (NAO) and tropical cyclogenesis. Despite being the season in which anticyclonic RWB events are most prevalent, no work has focused solely on the frequency, genesis, or variability of the synoptic environment surrounding the equatorward branch of anticyclonic RWB events during the North Atlantic summertime, providing motivation for this study. Using 58 years (1960–2017) of NCEP–NCAR reanalysis data, a comprehensive spatiotemporal climatology of North Atlantic equatorward anticyclonic RWB identified on the 350-K isentropic surface is developed and the synoptic environment surrounding these events from time- and high-PV-tongue centroid-relative perspectives is investigated. Consistent with previous studies, composites suggest that high-PV tongues associated with equatorward anticyclonic RWB introduce anomalously dry, stable extratropical air into the tropical environment, subsequently inhibiting convection there. Additionally, a connection between atmospheric responses to Pacific decadal oscillation (PDO) sea surface temperature (SST) anomalies and the intrabasin frequency of anticyclonic RWB events is uncovered and explored. Results from this study may aid short- to medium-range forecasts of North Atlantic tropical convection, with applications extending into the field of tropical cyclogenesis forecasting.

Sign in / Sign up

Export Citation Format

Share Document