J.Peralta, D.Luz, P.Machado CAAUL/Observatorio Astronmico de Lisboa (Universidade de Lisboa,...
-
Upload
asher-shepherd -
Category
Documents
-
view
214 -
download
0
description
Transcript of J.Peralta, D.Luz, P.Machado CAAUL/Observatorio Astronmico de Lisboa (Universidade de Lisboa,...
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.
?