Monday, 3 June 2002
Statistical properties of small-scale structure of temperature and LWC fields in marine stratocumulus observed in DYCOMS II field campaign.
In the Dycoms II experiment two very fast cloud probes: 1) Ultra Fast Temperature sensor (UFT-F), sampling at 1kHz and 10kHz, 2) PVM liquid water content probe (PVM), sampling at 1kHz, were located within 6m from each other under the wing of NCAR C-130 research aircraft. The small time constant of both sensors allows to investigate cloud structure down to scale of tens and even single centimeters. Unfortunately, due to the relative position of both sensors, no direct comparision of the small-scale properties of the temperature LWC fields are possible. In the presentation statistical properties of temperature and LWC fluctuations in the same region of cloud are analyzed and compared. Three types of cloud regions: one characterized by substantial LWC fluctuations with virtually constant temperature inside the cloud, second type with both: temperature and LWC fluctuations close to the cloud top, and third type with high temperature fluctuations and virtually no LWC at and above the cloud top are distinguished. Power spectra, structure functions and autocorrelatios of LWC and T fields characterising these regions will be presented and discussed in order to describe physical processes at the cloud top.