Campaign : CRYSTAL-FACE
2002.06.26 - 2002.08.01
Lead Scientist : James Mather
Data is available to the general public at the ARM Archive. Questions regarding CRYSTAL-FACE or the PARSL data set may be directed to Jim Mather at the Pacific Northwest National Laboratory (Jim.Mather@pnl.gov) or visit the CRYSTAL-FACE web site at http://cloud1.arc.nasa.gov/crystalface/
For data sets, see below.
From July 3-29, 2002 ARM took part in CRYSTAL-FACE (The Cirrus Regional Study of Tropical Anvils and Cirrus Layers -Florida Area Cirrus Experiment). CRYSTAL-FACE was organized by NASA but many agencies and institutions also played roles. The purpose of CRYSTAL-FACE was to study tropical convection and cirrus. Ultimately, there was great interest in carrying out such an experiment in the Tropical Western Pacific and it was likely that a future phase of CRYSTAL would be held in that region. Florida was chosen for the initial phase of CRYSTAL because it offered frequent deep convection and the logistics for holding an experiment there were much simpler than in the equatorial Pacific.
Much of the emphasis of CRYSTAL-FACE was on the aircraft component. There were six aircraft that were all based in Key West Florida and flew missions throughout the month over south Florida and on several occasions over the Carribean to study convection in the deep tropics. The aircraft included (in approximate order of maximum ceiling): the Twin Otter, Citation, P3, WB-57, Proteus, and ER-2. The experiment also included extensive satellite and modelling components as well as two fully instrumented ground sites.
ARM participated primarily by sponsoring the deployment of PARSL (The Pacific Northwest National Laboratory Atmospheric Remote Sensing Laboratory) in southwest Florida. PARSL is a mobile suite of instruments designed to measure the surface radiation budget and the atmospheric state and closely matches the instrumenation found at an ARM site. PARSL instruments included broad and narrowband radiometers, a sky imager, two cloud radars (94 and 35 GHz), a cloud lidar, surface meteorology sensors and a balloon borne sounding system.
PARSL was stationed at the Everglads National Park Visitor's Center in Everglades City. This site was located along the Gulf Coast, 120 km East of Miami and 150 km NNE of Key West. The PARSL site was referred to within CRYSTAL-FACE as the western ground site. The eastern ground site was located near Miami and included participants from NOAA/ETL, NASA Goddard, and the University of Miami. The site at Everglades City ground site was chosen because study of July convection patterns indicated that rainfall was more likely to inland than along the coast but upper level winds typically advected anvils over the southwest coast. This expectation was borne out during CRYSTAL-FACE. During CRYSTAL-FACE, the PARSL 94 GHz radar was operated over 150 hours, primarily between dawn and dusk when continental convection is active. Clouds were observed above 7 km approximately 40% of the time. Convective cores with accompanying high rain rates passed over the site on only two occasions during the month.
Not surprisingly, the south florida convection exhibited a strong diurnal cycle. PARSL radar data in combination with satellite images provided a detailed view of this timing. The western ground site was affected by near-shore maritime convection during the early morning and by continental
sea-breeze convection in the late afternoon. Cloud occurrence was least prevalent during the late morning and early afternoon. The timing of the diurnal cycle was often out of synch with aircraft missions which often flew earlier in the afternoon. Some potential cases for ground/aircraft comparison include a cirrus anvil on July 16, thin cirrus on July 23, and maritime convection on July 9.
Going into CRYSTAL-FACE much of the emphasis for the ground site participants was on comparisons of remote sensing retrievals of cloud properties with in situ observations from the aircraft. This will continue to be an area of emphasis; however, the limited amount of overpass time has caused us to spend more time than we might have otherwise, on other applications of the data. An important application will be providing a better view of the overall environment than can be provided by the aircraft.
During the CRYSTAL-FACE experiment, PARSL observed a variety of convective clouds at the western ground site in Everglades City. The radar-derived cloud properties as well as the surface radiation data clearly show the timing of the diurnal convective cycle. The radar data also provides details regarding the levels at which cirrus outflow typically occur. Although CRYSTAL-FACE was only a one month experiment, the south Florida area experienced several distinct meteorological regimes during this period. The PARSL sondes as well as the surface meteorological sensors show the transition between these periods. Meanwhile, cloud characteristics obtained from the radar and broadband radiometers change along with the meteorological forcing. Thus the PARSL data set, along
with the instruments stationed near Miami, will provide an important context for the in situ measurements obtained by the aircraft.
Campaign Data Sets
|IOP Participant||Data Source Description||Final Data|