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• 1. [Article] Kelvin waves in stratospheric temperature observed by the Microwave Limb Sounder

  The three-dimensional (3-D) structure of stratospheric Kelvin waves is revealed using data from the Microwave Limb Sounder for the period July 1992 to April 1993. Four Kelvin wave modes are identified, ...

  Citation × Citation Citation Abstract Copy Title: Kelvin waves in stratospheric temperature observed by the Microwave Limb Sounder Author: Dunkerton, Timothy J., Wu, Dong, Mote, Philip W. The three-dimensional (3-D) structure of stratospheric Kelvin waves is revealed using data from the Microwave Limb Sounder for the period July 1992 to April 1993. Four Kelvin wave modes are identified, two for zonal wave number 1 (k = 1) and two for k = 2, using extended empirical orthogonal functions. The 3-D structures of the modes agree with linear theory and satisfy the dispersion relation for Kelvin waves, and with periods ranging from 4.5 to 10 days the modes mostly fall near the boundary between ‘‘fast’’ and ‘‘slow’’ Kelvin waves [Canziani et al., 1998]. The analysis also identifies a feature that may correspond with the ‘‘pancake structures’’ associated with inertial instability. Title: Kelvin waves in stratospheric temperature observed by the Microwave Limb Sounder Author: Dunkerton, Timothy J., Wu, Dong, Mote, Philip W. The three-dimensional (3-D) structure of stratospheric Kelvin waves is revealed using data from the Microwave Limb Sounder for the period July 1992 to April 1993. Four Kelvin wave modes are identified, two for zonal wave number 1 (k = 1) and two for k = 2, using extended empirical orthogonal functions. The 3-D structures of the modes agree with linear theory and satisfy the dispersion relation for Kelvin waves, and with periods ranging from 4.5 to 10 days the modes mostly fall near the boundary between ‘‘fast’’ and ‘‘slow’’ Kelvin waves [Canziani et al., 1998]. The analysis also identifies a feature that may correspond with the ‘‘pancake structures’’ associated with inertial instability. Close

• 2. [Article] Intraseasonal variations of water vapor in the tropical upper troposphere and tropopause region

  We show the signature of the tropical intraseasonal oscillation (TIO) in upper tropospheric moisture and dynamical fields, roughly between 200 and 100 hPa. Relationships among these fields are examined ...

  Citation × Citation Citation Abstract Copy Title: Intraseasonal variations of water vapor in the tropical upper troposphere and tropopause region Author: Clark, Hannah L., Dunkerton, Timothy J., Mote, Philip W., Harwood, Robert S., Pumphrey, Hugh C. We show the signature of the tropical intraseasonal oscillation (TIO) in upper tropospheric moisture and dynamical fields, roughly between 200 and 100 hPa. Relationships among these fields are examined using lag-correlation analysis and using multivariate extended empirical orthogonal functions (MEEOFs), which maximize the shared explained variance among several fields for both spatial and temporal variations. The MEEOFs show that all of the fields respond to the TIO and that the TIO is the dominant factor influencing each of the fields on these timescales. Convection associated with the TIO moistens the upper troposphere up to about 150 hPa, as expected; the behavior at 100 hPa is more complex. Over the longitude range where the TIO is associated with convection, roughly 60°-180°E, 100-hPa temperature and water vapor tend to be reduced above convection on TIO timescales. East of 180°, though, the temperature and water vapor variations at 100 hPa become decoupled. The water vapor variations, like those of 200-hPa velocity potential, appear to speed up at about 180°E. Title: Intraseasonal variations of water vapor in the tropical upper troposphere and tropopause region Author: Clark, Hannah L., Dunkerton, Timothy J., Mote, Philip W., Harwood, Robert S., Pumphrey, Hugh C. We show the signature of the tropical intraseasonal oscillation (TIO) in upper tropospheric moisture and dynamical fields, roughly between 200 and 100 hPa. Relationships among these fields are examined using lag-correlation analysis and using multivariate extended empirical orthogonal functions (MEEOFs), which maximize the shared explained variance among several fields for both spatial and temporal variations. The MEEOFs show that all of the fields respond to the TIO and that the TIO is the dominant factor influencing each of the fields on these timescales. Convection associated with the TIO moistens the upper troposphere up to about 150 hPa, as expected; the behavior at 100 hPa is more complex. Over the longitude range where the TIO is associated with convection, roughly 60°-180°E, 100-hPa temperature and water vapor tend to be reduced above convection on TIO timescales. East of 180°, though, the temperature and water vapor variations at 100 hPa become decoupled. The water vapor variations, like those of 200-hPa velocity potential, appear to speed up at about 180°E. Close

• 3. [Article] Kelvin wave signatures in stratospheric trace constituents

  Connections, sometimes tenuous, have previously been noted between stratospheric Kelvin waves and several stratospheric trace constituents. The present study finds evidence of Kelvin wave signatures in ...

  Citation × Citation Citation Abstract Copy Title: Kelvin wave signatures in stratospheric trace constituents Author: Dunkerton, Timothy J., Mote, Philip W. Connections, sometimes tenuous, have previously been noted between stratospheric Kelvin waves and several stratospheric trace constituents. The present study finds evidence of Kelvin wave signatures in ozone from the Microwave Limb Sounder (MLS) and Cryogenic Limb Array Etalon Spectrometer (CLAES) instruments aboard the Upper Atmosphere Research Satellite. Predominant variations near 10 days are associated with a Kelvin wave mode previously identified in MLS temperature. Variations in CLAES nitrous oxide also show some evidence of influence by this Kelvin mode. The results presented here show that the observing characteristics of the instrument can influence the derived structure and properties of Kelvin waves. Title: Kelvin wave signatures in stratospheric trace constituents Author: Dunkerton, Timothy J., Mote, Philip W. Connections, sometimes tenuous, have previously been noted between stratospheric Kelvin waves and several stratospheric trace constituents. The present study finds evidence of Kelvin wave signatures in ozone from the Microwave Limb Sounder (MLS) and Cryogenic Limb Array Etalon Spectrometer (CLAES) instruments aboard the Upper Atmosphere Research Satellite. Predominant variations near 10 days are associated with a Kelvin wave mode previously identified in MLS temperature. Variations in CLAES nitrous oxide also show some evidence of influence by this Kelvin mode. The results presented here show that the observing characteristics of the instrument can influence the derived structure and properties of Kelvin waves. Close