Mado Observatory Summer School Alain Hauchecorne - - PowerPoint PPT Presentation

Maïdo Observatory Summer School

Alain Hauchecorne LATMOS-IPSL, UVSQ, CNRS alain.hauchecorne@latmos.ipsl.fr

Middle atmosphere dynamics

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Middle atmosphere = stratosphere + mesosphere, 12 to 90 km

The middle atmosphere

Middle atmosphere = stratosphere + mesosphere, 12 to 90 km

The middle atmosphere

From Haynes, 2004

From Haynes, 2004

Middle atmosphere radiative balance and general circulation

Observed zonal averaged temperature

Brasseur and Solomon, 2005; based on Fleming et al., 1998

Warm Cold Polar day Polar night

Radiative equilibrium temperature

Brasseur and Solomon, 2005; calculated by Fels, 1985

Cold Warm Polar night Polar day

Adiabatic heating/cooling in the atmosphere

Net adiabatic heating rate (K/day)

Brasseur and Solomon, 2005; from London, 1980

Heating Cooling Polar day Polar night

Residual circulation

Diabatic heating (cooling)  vertical ascent (descent) of air Continuity equation  meridional wind Polar day Polar night

Zonal wind: the geostrophic approximation

Coriolis force equilibrates Pressure gradient force Coriolis force = 2 w sin(latitude) w: Earth rotation rate Wind blows around depression

• anticlockwise in Northern Hemisphere
• clockwise in Southern Hemisphere

Zonal wind

Brasseur and Solomon, 2005; based on Fleming, 1988

Polar day Polar night

Antarctic polar vortex evolution 1996

UKMO analysis

Atmospheric waves in the atmosphere

Transport energy, momentum flux and atmospheric constituants Different kinds of waves:

• planetary waves: global scale
• gravity waves: local scale
• atmospheric tides: global scale, diurnal period, solar heating of

stratospheric ozone and tropospheric water vapour

Planetary Rossby waves

Meridional gradient of Coriolis force Hemispheric extension Upward propagation possible only if zonal wind > 0 (winter conditions in the stratosphere) Interaction with zonal wind: stratospheric warming

Temperature maps at 22 km

Winter 01/02/2010 Non zonal structure Planetary waves Summer 07/01/2010 Zonal structure

Rayleigh lidar observations

Observatoire de Haute-Provence

Backscatter lidar principle

Temperature measurements using Rayleigh Lidar

• Required pure molecular

scattering

• Density and pressure are

relative measurements

• Temperature is absolute

r(z) = f (N(z) dP(z) = -g(z)r(z)dz T(z) = MP(z) Rr(z) T(z) = M R gr(z')dz'

z

å

r(z) = Mg(z) R N(z')dz'

z top

å

N(z)

Temperature lidar profile At Maïdo Observatory, Reunion Island

OHP temperature evolution in winter 1996/97

paper!on!QBO).!The!GW! ,!estimated!in!the!equatorial!band!using!GPSK RO!data!(Fig.!12), is!enhanced!along!the!zero!wind!line!! !

!Evolution!of!the!temperature!at!OHP!during!winter!1996K 1997.!Days!with!measurements are!indicated!with!a!vertical!bar!at!the!top!of!the!figure.!Adapted!from!Hauchecorne!et!al.!(2006).

Temperature variability

Middle latitude (44°N) Tropics 21°N

Leblanc et al.

Non-linear phenomenon Planetary wave forcing in the troposphee Development depending on planetary wave amplitude and stratospheric zonal wind profile

Stratospheric warming 2009 Stratospheric warming: vortex splitting

Lidar profile evolution during a Sudden Stratospheric Warming

!

° ° ° × ° –

Stratosphere-troposphere dynamics coupling

Baldwin and Dunkerton, JASTP, 2005

Pressure and temperature perturbations generated in the upper stratosphere can propagate down to the troposphere and the surface

Stratosphere-troposphere dynamics coupling

Baldwin and Dunkerton, JASTP, 2005

Pressure and temperature perturbations generated in the upper stratosphere can propagate down to the troposphere and the surface

Impact of SSW on medium range weather forecast

Charlton Perez et al., 2015

Surface temperature 15 to 30 days after a Strat Warm event Averaged over 15 SSWs

Gravity waves

Gravity force Local extension (10 à 1000 km) Main sources

• Orography (Lee waves)
• Deep convection
• Jet stream (geostrophic adjustment)

Gravity wave propagation and breaking

Brasseur and Solomon, 2005; from Lindzen, 1981

GW breaking GW breaking

Gravity wave breaking  wind deceleration Vertical and meridional wind  summer mesosphere cooling and winter mesosphere warming

Lidar temperature profile with a gravity wave

Temperature profile evolution during one night

(21° 55°

!Consecutive!lidar!temperature!profiles!at!Maïdo!Observatory!on!21!November!2013.! profile!is!integrated!during!15!minutes.!A!5!K!shift!is!applied!between!two!consecutive!pro

Temperature anomaly: gravity wave propagation

K K

GW characterization

NDACC Rayleigh Temperature lidars: from the variance of lidar signal fluctuations at OHP COSMIC-GPS radio-occultation: from the fluctuations in temperature profiles in a 10° longitude by 5° latitude box around OHP Radiosoundings: from the fluctuations in temperature profiles at Nîmes (100 km from OHP) GW potential energy per unit of mass

Ep = 1 2 g2 N 2 æ è ç ö ø ÷ T ' T æ è ç ö ø ÷

2

Climatology of GW potential energy from OHP lidar data

Mze et al., JGR, 2014

37

Gravity waves and thunderstorms

Infrasounds COSMIC-GPS WRF model / Lidar WRF

Gravity wave potential energy

Costantino et al., 2015

Seasonal evolution of GW potential energy

Mze et al., JGR, 2014

From http://www.cosmic.ucar.edu/related_papers/GPS_RO_cartoon.jpg

GPS radio-occultation technique

° ° ° × °

Figure 2. Same as Fig. 1b for the period October 2012 – April 2013.

GW potential energy from combined GPS-RO and lidar data in winter 2012-2013 GW potential energy at the Equator and link with the QBO from GPS-RO data

Doppler wind lidar

The Doppler shift is proportionnal to the radial wind Urad ≈ (SA-SB)/(SA+SB)

OHP wind lidar

Doppler wind lidar profile

Zonal wind at Maïdo observed by lidar and radiosonde on 7 June 2016

Gravity wave in Doppler wind

(courtesy of C. Souprayen)

zonal meridional

Gravity waves observed from space

Preusse, 2006

Infrared composite from geostationary satellites

Gravity waves observed from space

Preusse, 2006

GOMOS principle

From 10 km up to 120 km One star spectrum every 0.5 s Scintillation information 1000 Hz

GOMOS scintillation measurements towards visualization of gravity wave breaking

Star scintillation

Turbulence structure CT

2

High resolution temperature profile

Sofieva et al., 2007

The Quasi Biennial Oscillation

QBO cycle Periodic evolution of the equatorial zonal wind, period ≈28 months

Review Baldwin et al., Rev. Geophys. 2001

Equatorial waves

­ β­ ­ ­

Kelvin waves Purely zonal Eastward phase propagation Rossby-gravity waves zonal and meridional Westward phase propagation

From Wheeler et al., 2000

QBO mechanism

Momentum flux deposition from eastward and westward propagating waves

• Kelvin waves  E
• Rossby-gravity waves  W
• Gravity waves  E and W

Disruption of QBO in 2016

Newman et al., GRL, 2016

Disruption of QBO in 2016

Newman et al., GRL, 2016

Conclusion

The middle atmophere dynamics plays an important role in the coupling between the different atmospheric layers and in the transport and mixing of atmospheric constituents Lidars, with other instruments installed at OHP and Maïdo and satellite observations, are very efficient tools for atmospheric dynamics studies

High resolution transport model MIMOSA

Potential vorticity (PV)

In absence of diabatic effects, an air mass is moving along isntropic surfaces and its PV is conserved

V

Danielsen (1968)

First evidence : Increase of ozone and radioactivity in a tropopause folitation

Relation tracer-PV

First use of PV conservation to study the polar vortex dynamicspolaire

McIntyre and Palmer, Nature, 1983

PV and polar vortex

Projet EC-FP5 METRO-THESEO 1999-2000

Objective: to study the meridional transport of ozone in the lower and middle stratosphere (vortex filamentation, tropical intrusions) Tools: Lidar ozone ALTO on board French Falcon IGN-INSU Lidar ozone at Observatoire de Haute-Provence Need to have a isentropic transport model for the planning of aircraft flights and the interpretation

Advection Semi-implicit method Advection during 6 hours Interpolation on initial grid

Advection and regridding

Polar filament seen by the OHP ozone lidar

MIMOSA on AERIS/ESPRI database

475 K ≈ 19 km

MIMOSA service on AERIS/ESPRI

http://ether.ipsl.jussieu.fr/ether/pubipsl/mimosa_fr.jsp

Scientific coordinator: Alain Hauchecorne (LATMOS) Technical coordinator: Cathy Boonne (IPSL)