J.Peralta, D.Luz, P.MachadoCAAUL/Observatorio Astronómico de Lisboa

(Universidade de Lisboa, PORTUGAL)

Contribution from simultaneous wind measurements with VMC

and ground-based observations

Global-scale Waves: Tides

-Persistent global oscillations found in wind, temperature, pressure, etc…

-Global-scale atmospheric gravity waves excited by different sources.

• K=2 and K=4.

• Mean Amplitudes:~ 2 m/s [K=2]~ 5 m/s [K=4](≤ 20% zonal comp.)

• K=4 dominant at lower latitudes.

• Retrograde acceleration at midday.

Solar Tides in the Zonal Wind

• K=1.

• Mean Amplitudes:~ 6 m/s [K=1](>>100% merid. wind)

• Variations with the Latitude.

• Poleward acceleration at midday.

Solar Tides in the Meridional Wind

Zonal Disturbances:• Effect weaker than meridional.• Absence for Diurnal Tide.

Diurnal Tides: Main implications

Meridional Disturbances:• Strong effect of Diurnal Tide.• DAY: Poleward acceleration• NIGHT:Equatorward acceleration

Diurnal Tides: Spatial Structure

Wave fronts matching lines of constant SZA explains absence of K=1 on Zonal Wind.

Mesoscale Waves: Cloud Tops

Mesoscale Waves: Lower Clouds

Mesoscale Waves: Characterization

Packet LenghtWavelength

Packet Width

Packet OrientationPhase VelocityAverage Zonal WindPacket Location

Role of Ground-based Observationsconcerning the Waves

GLOBAL-SCALE:• Winds from Doppler

technique allow accuracy enough to measure Tidal effects.

• Characterize Solar Tide at lower latitudes.

MESOSCALE WAVES:• Nowadays enough spatial

resolution to resolve mesoscale wave effect on winds.

• Waves could be the reason for the wind disturbances.(Machado, 2012)

Simultaneous Wind MeasurementsGround-based and Remote Sensing (I)

GROUND-BASED:ESPaDOnS high-resolution echelle spectrograph[DOPPLER EFFECT]

REMOTE SENSING (VEX):VMC Camera with an UV filter to sense cloud tops[CLOUD TRACKING]

Simultanous Observations:(ongoing work by Machado et al.)• 2007 May 24 (20 VMC images)• 2007 July 2-4 (8 VMC images)• 2007 Sept 30 (11 VMC images)

Simultaneous Wind MeasurementsGround-based and Remote Sensing (II)

GROUND-BASED:TNG/NICS (NIr Camera Spectrometer) to sense the nightside lower clouds[CLOUD TRACKING]

REMOTE SENSING (VEX):VMC Camera with an UV filter to sense cloud tops[CLOUD TRACKING]

• Principal Investigator: D.Luz• Images to be taken 2012 July 6-21• 3D Winds after VIRTIS-IR failure

Simultaneous Wind MeasurementsGround-based and Remote Sensing (III)

GROUND-BASED:YET TO BE CONFIRMED ! [DOPPLER EFFECT]

REMOTE SENSING (VEX):SOIR IR high-resolution spectrometer to sense cloud tops and mesosphere[DOPPLER EFFECT]

• Ongoing work by J.Peralta, D.Luz, P.Machado, T.Widemann, A.Mahieux and A.C. Vandaele.

• First fine characterization of the circulation in the upper atmosphere.

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