Satellite, model and ground based observations of tides:

Results from the Second CAWSES Global Tidal Campaign Workshop

Presented on behalf of the

2007 CAWSES Tidal Workshop Participants

TIMED Workshop

September 18, 2007

2007 Workshop Participants

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• Back row: Dr. Norbert Greiger, Alexander Haefele, Dr. Jens Oberheide, Aaron Power, Dr. William Ward, Dr. Ding Yi Wang.

• Front row: Dr. Takuji Nakamura, Jian Du, Dr. Larisa Goncharenko, Loren Chang, Dr. Peter Hoffmann.

Background & Motivation

• Atmospheric tides are the dominant global scale dynamical feature of the mesosphere and lower thermosphere region.

• The global perspective required to understand the sources, variability, propagation, and interactions of the tides requires satellite data in conjunction with a global ground based network.

• Computer models are required to understand tidal structures and processes.

• The CAWSES tidal campaigns are intended to bring together the observational and modeling community for periods of concentrated effort to resolve the tidal structures in the atmosphere.

… and 100+ scientists from 30+ institutions!

Map courtesy of J. Oberheide

Campaign Overview

• 1-2 month observational campaigns:– 1st Campaign: September 1 - October 31, 2005.

– 2nd Campaign: March 1 - April 30, 2007.

– 3rd Campaign: June 1 - August 15, 2007.

– 4th Campaign: December 1, 2007 - January 31, 2008.

• 2 Workshops for coordinated data and model analysis:– August 27 - 30, 2007: Emphasis on observational data analysis.

– August 25 - 29, 2008: Emphasis on modeling and understanding observations.

• Web based data center and further information available at:

http://www.unb.ca/physics/CAWSES_GTC

Some Objectives

• Are the various datasets consistent with one another?

• What is the role of nonmigrating tides in spatial and temporal variation of ground-based observations?

• Can the sources of observed components be identified?

• Total diurnal tidal amplitudes from TIDI. Reconstructed from the analyzed nonmigrating components(W4, W3, W2, S0, E1, E2, E3) and the the migrating tide W1. Migrating tide reconstructed from SABER temperature observations.

• Significant longitude modulation from nonmigrating tides.

• Diurnal tide amplitude at Platteville MF radar is relatively small.Data courtesy of J. Oberheide.

• Monthly mean diurnal tide measurements from TIDI and Platteville MF radar during 1st tidal campaign.

• Differences between TIDI and radar amplitudes and phases are small.

• Similar situation for zonal wind field amplitudes.

TIDI / Radar Comparison(Platteville 24h Meridional Wind: 42.6N, 105W)

Data courtesy of J. Oberheide, A. Manson, C. Meek, D. Thorsen, and S. Avery.

Lidar / ISR ComparisonsNorthern Hemisphere Midlatitudes (September / October 2005)

• Fort Collins lidar (41N, 105W) + Millstone Hill ISR (42.6N, 71.5W) averaged over 1st tidal campaign.

• Both instruments show high day to day variability.

• Good agreement between lidar and ISR measurements in both U and V, as well as with TIDI 24h component.

Courtesy of L. Goncharenko, lidar data from C.Y. She.

CMAM / WACCM3 ComparisonPlatteville Meridional Winds (September)

• Monthly mean 24-h amplitudes and phases at gridpoint nearest to Platteville from general runs of WACCM3 and CMAM. TIDI monthly means for 24-h.

• Tidal amplitudes considerably weaker in WACCM3 compared to CMAM below 100 km during March (difference ~ 20 m/s).

• WACCM3 24-h vertical wavelengths very long (evanescent) compared to CMAM and TIDI (propagating).

CMAM results courtesy of J. Du

• Equatorial zonal wind tides at Kototabang are relatively large.

Data courtesy of J. Oberheide.

• Monthly mean diurnal tide measurements from TIDI and Kototabang MR radar during 2nd tidal campaign.

• Good agreement below 95 km, amplitude discrepancy above 95 km in V.

TIDI / Radar Comparison(Kototabang 24h Zonal Wind: 0N, 100E)

Data courtesy of J. Oberheide and T. Nakamura.

CMAM / WACCM3 ComparisonKototabang Zonal Wind (March / April)

• Monthly mean 24-h amplitudes and phases at gridpoint nearest to Kototabang from general runs of WACCM3 and CMAM. TIDI 24-h mean for March.

• Good agreement between WACCM3 and CMAM.

• Amplitudes in both models larger than TIDI. Phases show good agreement.

CMAM results courtesy of J. Du

Conclusion

• A brief summary of results from the 2007 CAWSES Global Tidal Campaign Workshop has been presented.

• Good agreement found between various observation and model datasets during the tidal campaigns.

Future Activities

• 4th Tidal Campaign:

December 1, 2007 -

January 31, 2008

• Tidal Workshop:

August 25 - 29, 2008

• Your participation in the tidal campaigns is encouraged!

• More info at: http://www.unb.ca/physics/CAWSES_GTC

Backup Slides

Steering Committee• W. E. Ward, University of New Brunswick, Canada (Chair)• J. M. Forbes, University of Colorado, USA• N. Grieger, IAP Kühlungsborn, Germany• S. Gurubaran, Indian Institute of Geomagnetism, India• M. E. Hagan, National Center for Atmospheric Research, USA• K. Hamilton, University of Hawaii, USA• R. S. Lieberman, Northwest Research Associates, USA• D. R. Marsh, National Center for Atmospheric Research, USA• M. G. Mlynczak, NASA Langley Research Center, USA• T. Nakamura, Kyoto University, Japan• J. Oberheide, University of Wuppertal, Germany• D. Pancheva, University of Bath, UK• H. Takahashi, INPE, Brasil

Project under Theme 3 of SCOSTEP’s CAWSES program.

TIDI / Radar Comparison(Platteville 24h Meridional Wind: 42.6N, 105W)

• Diurnal tide meridional wind fields from TIDI and Platteville MF radar during 1st campaign (September / October 2005).

• TIDI data uses 60-day running mean, while radar uses 4-day running mean. This explains the smoothness of the TIDI data.

• Radar reveals significant short-term variability (~6.5 day period).

Data courtesy of J. Oberheide, A. Manson, C. Meek, D. Thorsen, and S. Avery.

• Significant day to day variability.

CMAM / WACCM3 Comparison (Platteville 24h Meridional Wind: 42.6N, 105W)

• Monthly mean diurnal tide measurements from TIDI and Kototabang MR radar during 2nd tidal campaign.

• Good agreement below 95 km, amplitude discrepancy above 95 km.

TIDI / Radar Comparison(Kototabang 24h Meridional Wind: 0N, 100E)

Data courtesy of J. Oberheide and T. Nakamura.

TIDI / Radar Comparison(Kototabang 24h Meridional Wind: 0N, 100E)

• Diurnal tide measurements from TIDI and Kototabang MR radar during second tidal campaign (March / April 2007).

• Both datasets fit over 60-day running mean.

• Excellent agreement in time evolution.

• Good agreement below 95 km, amplitude discrepancy above 95 km.

Data courtesy of J. Oberheide and T. Nakamura.

• Similar spatial and temporal structure.

• Phase structure highly variable in CMAM compared to WACCM3.

CMAM / WACCM3 Comparison (Kototabang 24h Meridional Wind: 0N, 100E)

CMAM / WACCM3 ComparisonKototabang Meridional Winds (March / April)

• Monthly mean 24-h and 12-h amplitudes and phases at gridpoint nearest to Kototabang from general runs of WACCM3 and CMAM.

• Tidal amplitudes and phases comparable in both models below 90 km. 24-h V amplitudes disagree above 90 km.

CMAM results courtesy of J. Du

Microwave [H2O] Observations(Bern: 47N, 7E)

• [H2O] from MIAWARA microwave radiometer. Diurnal evolution over 2 days at 64 km.

• Temperatures are climatological monthly means from SABER (2002-2006)

• Strong correlation between [H2O] and temperature, linked by vertical motion and positive vertical [H2O] gradient below the mesospheric [H2O] layer.Microwave data courtesy of A. Haefele.

SABER courtesy of J. Forbes.