Coincident Imaging and Spectrometric Observations of Zenith OH Nightglow Structure
During the ALOHA-90 campaign a novel comparative study was made between near infrared wave structure imaged in the zenith using a CCD camera and that detected at infrared wavelengths by a Fourier Transform Spectrometer. Coincident measurements were made briefly on several occasions and for an extended period on 31 March. The temporal variations imaged in the near infrared structure during this night almost completely matched those detected in the OH (3,1) band spectrometer data when similar viewing fields were compared. However, the image data also displayed small scale wave forms that were not resolved by the larger field instrument. These structures exhibited significant changes in brightness and position on a time scale much shorter than the local Brunt-Vaisala period indicating that very high resolution measurements are necessary to investigate short period (<20 min) upper atmospheric wave motions.
Observations of the OH Meinel (6,2) and O2 atmospheric (0,1) Nightglow emissions from Maui during th
Observations are reported from a CCD nightglow camera deployed on Maui during ALOHA-90. These data show that there were periods of both strong and weak gravity wave activity, that background winds in the direction of wave propogation can be derived using airglow data alone, and that there may be a connection between sporadic Na and large-scale wave activity. These data are in fair to good agreement with models of wave induced airglow fluctuations.
The potential vorticity flux through the Yucatan Channel and the Loop Current in the Gulf of Mexico
Two‐year‐long time series of current and density structure measurements across the Yucatan Channel's main section allow the calculation of the time‐dependent potential vorticity flux between the Gulf of Mexico and the Caribbean Sea, which is characterized by alternating periods of positive (cyclonic) and negative (anti‐cyclonic) vorticity influx. Periods of negative cumulative vorticity influx are related to the Loop Current extending into the Gulf of Mexico, whereas periods of positive cumulative vorticity influx relate to a Loop Current retraction, sometimes coincident with the shedding of an anti‐cyclonic eddy.