Stratospheric Gravity Waves as a Proxy for Hurricane Intensification: a Case Study of Mesoscale Simulations for Hurricane Joaquin

<table><tbody><tr><td> Planetary waves disturbed the hitherto stable Arctic stratospheric polar vortex mid of January 2016 in such a way that unique tropospheric and stratospheric flow conditions for vertically and horizontally propagating mountain waves developed. Co-existing strong low-level westerly winds across almost all European mountain ranges plus the almost zonally-aligned polar front jet created these favorable conditions for deeply propagating gravity waves. Furthermore, the northward displacement of the polar night jet resulted in a wide-spread coverage of stratospheric mountain waves trailling across northern Europe. This paper describes the particular meteorological setting by analyzing the tropospheric and stratospheric flows based on the ERA5 data. The potential of the flow for exciting internal gravity waves from non-orographic sources is evaluated across all altitudes by considering various instability indices as &#948; , Ro, Ro &#950; , Ro&#8869; , and &#916; NBE. The analyzed gravity waves are described and characterized in terms of commonly used parameters. The main finding of this case study is the exceptionally vast extension of the mountain waves trailing to high latitudes originating from the flow across the mountainous sources that are located at about 45 N. As a useful addition to the case study, tracks for potential research flights are proposed that sample the waves by a vertically pointing airborne remote-sensing instrument. Benefits and drawbacks of the different approaches to observe the meridional focussing of the mountain waves into the polar night jet are discussed. </td> </tr></tbody></table>&#160;

Download Full-text

VISIR-1.b: ocean surface gravity waves and currents for energy-efficient navigation

Geoscientific Model Development ◽

10.5194/gmd-12-3449-2019 ◽

2019 ◽

Vol 12 (8) ◽

pp. 3449-3480 ◽

Cited By ~ 2

Author(s):

Gianandrea Mannarini ◽

Lorenzo Carelli

Keyword(s):

Energy Efficiency ◽

Gravity Waves ◽

Ocean Surface ◽

Surface Gravity ◽

Ocean Current ◽

Ship Routing ◽

Surface Gravity Waves ◽

Waves And Currents ◽

The Impact

Abstract. The latest development of the ship-routing model published in Mannarini et al. (2016a) is VISIR-1.b, which is presented here. The new version of the model targets large ocean-going vessels by considering both ocean surface gravity waves and currents. To effectively analyse currents in a graph-search method, new equations are derived and validated against an analytical benchmark. A case study in the Atlantic Ocean is presented, focussing on a route from the Chesapeake Bay to the Mediterranean Sea and vice versa. Ocean analysis fields from data-assimilative models (for both ocean state and hydrodynamics) are used. The impact of waves and currents on transatlantic crossings is assessed through mapping of the spatial variability in the tracks, an analysis of their kinematics, and their impact on the Energy Efficiency Operational Indicator (EEOI) of the International Maritime Organization. Sailing with or against the main ocean current is distinguished. The seasonal dependence of the EEOI savings is evaluated, and greater savings with a higher intra-monthly variability during winter crossings are indicated in the case study. The total monthly mean savings are between 2 % and 12 %, while the contribution of ocean currents is between 1 % and 4 %. Several other ocean routes are also considered, providing a pan-Atlantic scenario assessment of the potential gains in energy efficiency from optimal tracks, linking them to regional meteo-oceanographic features.

Download Full-text

Orographic and convective gravity waves above the Alps and Andes mountains during GPS radio occultation events – a case study

10.5194/amt-2017-245-ac2 ◽

2018 ◽

Author(s):

Anonymous

Keyword(s):

Gravity Waves ◽

Radio Occultation ◽

Andes Mountains ◽

Gps Radio Occultation ◽

The Alps ◽

Convective Gravity Waves

Download Full-text

Detection of gravity waves across the USArray: A case study

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2013.06.042 ◽

2014 ◽

Vol 402 ◽

pp. 346-352 ◽

Cited By ~ 16

Author(s):

Catherine D. de Groot-Hedlin ◽

Michael A.H. Hedlin ◽

Kristoffer T. Walker

Keyword(s):

Gravity Waves

Download Full-text

Gravity waves generated by a tropical cyclone during the STEP tropical field program: A case study

Journal of Geophysical Research Atmospheres ◽

10.1029/92jd01679 ◽

1993 ◽

Vol 98 (D5) ◽

pp. 8611-8638 ◽

Cited By ~ 148

Author(s):

L. Pfister ◽

K. R. Chan ◽

T. P. Bui ◽

S. Bowen ◽

M. Legg ◽

...

Keyword(s):

Tropical Cyclone ◽

Gravity Waves

Download Full-text

Simultaneous lidar observations of temperatures and waves in the polar middle atmosphere on both sides of the Scandinavian mountains: a case study on 19/20 January 2003

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-4-969-2004 ◽

2004 ◽

Vol 4 (1) ◽

pp. 969-989 ◽

Cited By ~ 1

Author(s):

U. Blum ◽

K. H. Fricke ◽

G. Baumgarten ◽

A. Schöch

Keyword(s):

Gravity Waves ◽

Middle Atmosphere ◽

Temperature Structure ◽

Vertical Wavelength ◽

Mountain Ridge ◽

Induced Gravity ◽

Simultaneous Measurements ◽

Wave Patterns ◽

Atmospheric Gravity

Abstract. Atmospheric gravity waves have been the subject of intense research for several decades because of their extensive effects on the atmospheric circulation and the temperature structure. The U. Bonn lidar at the Esrange and the ALOMAR RMR lidar at the Andøya Rocket Range are located in northern Scandinavia 250 km apart on either side of the Scandinavian mountain ridge. During January and February 2003 both lidar systems conducted measurements and retrieved atmospheric temperatures. On 19/20 January 2003 simultaneous measurements for more than 7 h were possible. Although during most of the campaign time the atmosphere was not transparent for the propagation of orographically induced gravity waves, they could propagate and were observed at both lidar stations during these simultaneous measurements. The wave patterns at ALOMAR show a random distribution with time whereas at the Esrange a persistency in the wave patterns is observable. This persistency can also be found in the distribution of the most powerful vertical wavelengths. The mode values are both at about 5 km vertical wavelength, however the distributions are quite different, narrow at the Esrange containing values from λz=2–6 km and broad at ALOMAR, covering λz=1–12 km vertical wavelength. At both stations the waves deposit energy in the atmosphere with increasing altitude, which leads to a decrease of the observed gravity wave potential energy density with altitude. These measurements show unambigiously orographically induced gravity waves on both sides of the mountains as well as a clear difference of the characteristics of these waves, which might be caused by different excitation and propagation conditions on either side of the Scandinavian mountain ridge.

Download Full-text

Formation of ice supersaturation by mesoscale gravity waves

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-67-2005 ◽

2005 ◽

Vol 5 (1) ◽

pp. 67-100 ◽

Cited By ~ 1

Author(s):

P. Spichtinger ◽

K. Gierens ◽

A. Dörnbrack

Keyword(s):

Gravity Waves ◽

Internal Gravity Waves ◽

Specific Humidity ◽

Cirrus Cloud ◽

Weather Forecasts ◽

Medium Range ◽

Formation And Evolution ◽

The Baltic ◽

Wave Induced ◽

Mesoscale Simulations

Abstract. We investigate the formation and evolution of an ice-supersaturated region (ISSR) that was detected by means of an operational radiosonde sounding launched from the meteorological station of Lindenberg on 21 March 2000, 00:00 UTC. The supersaturated layer was 5 situated below the local tropopause, between 320 and 408 hPa altitude. Our investigation uses satellite imagery (METEOSAT, AVHRR) and analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF). Mesoscale simulations reveal that the ISSR was formed by a temporary vertical uplift of upper tropospheric air parcels by 20 to 40 hPa in 1 to 2 h. This resulted in a significant local increase of the 10 specific humidity by the moisture transport from below. The ascent was triggered by the superposition of two internal gravity waves, a mountain wave induced by flow past the Erzgebirge and Riesengebirge south of Lindenberg, and an inertial gravity wave excited by the anticyclonically curved jet stream over the Baltic Sea. The wave-induced ISSR was rather thick with a depth of about 2 km. The wave-induced upward motion 15 causing the supersaturation also triggered the formation of a cirrus cloud. METEOSAT imagery shows that the cirrus cloud got optically thick within two hours. During this period another longer lasting thin but extended cirrus existed just beneath the tropopause. The wave-induced ISSR disappeared after about half a day in accordance with the decaying wave activity.

Download Full-text