DYNAMICAL CHARACTERISTICS OF CIRRUS CLOUDS FROM AIRCRAFT AND RADAR OBSERVATIONS IN MICRO AND MESO-GAMMA SCALES

Cirrus clouds that formed on 26 November and 6 December 1991 during th e First International Satellite Cloud Climatology Project Regional Exp eriment (FIRE) II, which took place over the Kansas region, are studie d because of significant dynamic activity in the micro (< 1 km) and me so gamma (< 25 km) scales within the cloud. Observations are obtained from the NCAR King Air, NOAA Doppler, and PSU conventional radar. For this reason coherent structures (e.g., cells, vortex) that transfer si gnificant heat, moisture, and turbulence are analyzed using aircraft a nd radar observations. Aircraft data is collected at 20 Hz, and calcul ations are made at two different scales. Scale separation is chosen at about 1 km. A coherence analysis technique is used to specify the cor relation between temperature and vertical velocity w fluctuations. A s wirling coefficient, indicating spirality, is calculated to better und erstand cloud dynamics. Sensible heat, latent heat, and radiative flux es are compared with each other in two scales. Results showed that dyn amic activity, including w about +/- 1.5 m s(-1), and mean sensible he at fluxes (SHFs) and latent heat fluxes (LHFs) similar to 10 W m(-2), is estimated to be much larger for the 26 November case compared to th e 6 December case. The swirling coefficient is estimated to be larger in upper and lower levels compared to those in middle levels for both days. Individual values of SHFs and LHFs are also found to be comparab le with those of FIRE I. The size of coherent structures is estimated from aircraft and radar measurements to be about 0.5 and 3.5 km.