Solar thermal tidal waves
observations from ground
based Na lidar and
Spaceborne SABER/TIMED
instrument
Titus Yuan
Center for Atmospheric and Space
Sciences
Utah State University
Outline
•
•
•
•
Na lidar diurnal cycle observations
SABER tidal observations
Temperature diurnal tide comparison
Temperature semidiurnal tide
comparisons
• Summary
This is the
longest Na lidar
campaign (Sep.
21-29, 2003).
Temperature
(top)
Zonal wind
(middle)
Meridional wind
(bottom)
Linear Least squares fitting of
Lidar Diurnal Cycle Observation
Raw data
(T, U&V)
Mean fields
(T, U&V)
 2j

 ( z , t )     A j ( z ) cos 
(t   j )  R ( z , t )
 24

j 1
4
Amplitudes
Phase
j=1 for diurnal tide (24-hour)
j=2 for semidiurnal tide (12-hour)
j=3 for terdiurnal tide (8-hour)
j=4 for quarterdiurnal tide (6-hour)
TIMED/SABER Diurnal Tide
Migrating
tidal
component
TIMED/SABER Semidiurnal Tide
Migrating
tidal
component
LIDAR, HAMMONIA and
SABER
Thanks J. Forbes and X. Zhang for
SABER tidal wave data and H.
Schmit for HAMMONIA data
Diurnal Tidal Amplitude (K)
SABER
HAMMONIA
Na lidar
Diurnal tidal phase (Hr-LT)
Semidiurnal Tidal Amplitude
Semidiurnal Tidal Phase (Hr-Lt)
Summary
• The diurnal tide comparison shows good agreement among the
three (two experimental observations and model simulation) in
spring, late summer and early fall season. The different tidal
behavior in winter revealed by lidar is most likely induced by
nonmigrating tide that has short term variability.
• The semidiurnal tide comparison shows extremely well
agreement among the three.
• This study shows both experimental instruments are capable of
capturing the major features of solar thermal tides. While
SABER is more suitable for tidal wave global distribution, lidar
can observe short-term tidal wave variability and reveal the
dynamics behind.