1. CEDAR Frontiers: Tidal variability and wave interactions in the MLT region
Chiao-Yao (Joe) She
Colorado State University
Richard L. Collins
University of Alaska Fairbanks
In one sentence: It is very much there, yet scientists can’t predict it, nor do they know how to interpret it.
24 h lidar measurements of Na density, temperature (top) and potential temperature (bottom) at ort Collin.

2. Tidal-GW interactions
Planetary-GW interactions
Nine-day continuous observation
Tidal perturbations & variability
She et al., GRL, 2004

3. Some Facts and Questions
Why do tidal models predict semidiurnal tidal amplitudes much smaller than observed amplitudes?
Possible causes: (1) lower atmospheric sources are not resolved correctly, (2) vertical resolution needs to be higher (3) influence of tide-GW interaction unclear.
In view of observed midnight diurnal local heating, to what extent does the phase of temperature tide can be uncorrelated with the phase of horizontal wind tide?
More difficult to handle tidal variability : need to know (1) GW sources (time and space), (2) the presence of PWs and their modes, (3) the prescription of tide, GW and PW interactions.

4. Truely Coordinated Campaigns
PSMOS June-August 1999 Campaign (Pancheva et al., JASTP, 2002) – somewhat coordinated
First CAWSES Tidal Campaign, Sep 01 – Oct 31, 2005 (Leader: W. Ward) – somewhat coordinated
Coordinated campaigns with well-distributed Radars (Meteor, MF and ISR), Lidars (Metals with TUV_24-hr capability, Rayleigh) and Satellite diagnostics will fully characterize large-scale waves and advance our understanding of tidal variability and wave interactions.

5. Proposed Class I Instruments and Coordinated Campaigns
Beef up all 3 sodium lidars in the CRRL to 24-hour capability and large telescope
Mobile lidars in concert with AMISR
More stations (both radar and lidar) to cover minimal longitudes and latitudes as required by modelers
Community designed (led by modelers and wave specialists, reality-checked by instrument “owners”) coordinated campaigns.