Humberto COVES Experiment Data Set Analysis & Applications Group GROUP MEMBERS : Sim Aberson (HRD) Mike Black (HRD) Pete Black (HRD) Joe Cione (HRD) Peter Dodge (HRD) John Kaplan (HRD) Frank Marks (HRD) Mark Powell (HRD) Rob Rogers (HRD/UM-CIMAS) Eric Uhlhorn (HRD/UM-CIMAS)

OUTSIDE COLLABORATORS :
Jeff Halverson (NASA/GSFC/MAPB & UMBC-JCET) Andy Heymsfeld (NCAR/MMM) Edward Walsh (NASA/GSFC/WFF) GOALS:

The primary purpose of the Coordinated Observations of Vortex Evolution and Structure (COVES) experiment is to produce two complete snapshots of the three-dimensional structure of a mature TC and its environment by collecting and analyzing simultaneous in situ and remote-sensed observations from several different aircraft and instruments on multiple scales. The observations are to be obtained vertically throughout the depth of the troposphere and down to approximately 200 m below the sea surface and horizontally out to 1000 km from the storm center over two successive days. Ideally, the candidate storm will be undergoing a significant period of strengthening or weakening during the experiment. The snapshots will then be used to document the temporal evolution of the storm and environmental structure and how the features relate to intensity change, which falls under the HRD Hurricane Intensity Change goal. This also fulfills the foremost goal of the U.S. Weather Research Program's (USWRP) Hurricane Landfall 2001 initiative.

The Hurricane Humberto COVES data sets give unprecendented, multi-scale depictions of a hurricane and its environment. These depictions will provide a unique opportunity to improve the basic understanding of how storm structure, internal dynamics, and environmental interactions affect intensification. In order to achieve this, the group will specifically:

The group will then utilize the analyses and derived products in applications to:

Dropsonde, Rawinsonde, P-3 Flight Level, and GOES Satellite Wind Data The dropsonde data are first post-processed to correct for errors and eliminate observational noise. The data from each sonde is then smoothed with a 100 mb low-pass filter and sampled every 50 mb. The rawinsonde data are also smoothed and sampled in a similar manner. A 60 s low-pass filter is applied to P-3 flight level data are filter 60 s, and they are sampled temporally at resolutions similar to the spacing between the dropsonde observations. Processed visible, IR, and water vaport channel GOES satellite wind observations were obtained from Chris Velden of CIMSS at the University of Wisconsin. Wind observations from the dropsonde, rawinsonde, P-3 aircraft, and satellite platforms within plus or minus [substitute symbol here] six hours of the central nominal analysis time were analyzed using the nested HRD spline analysis (HSA) techniques. The HSA procedures are similar to those outlined by Franklin et al. (1996) and Feuer and Kaplan (1995) for analyzing winds in the storm environment and by Franklin et al. (1993) for analyzing winds in the inner core and environment of Hurricane Gloria of 1985. A multiply nested scheme is used to resolve various regions of Humberto and the surrounding atmospheric flow. The filter wavelengths on each mesh are chose to be representative of the desired resolution scale and compatible with the average spacing of the data. Circular arrays of synthetic winds with values determined by a scanning algorithm are employed to constrict the vortex inner core, fill data void regions, and prevent aliasing. In the later stages of the project, detailed kinematic and thermodynamic analyses that integrate all of the data sets from the different probes and instruments will be produced using the full HSA procedure, including the vertical iteration steps. ACCOMPLISHMENTS:

During 23-25 September 2001, HRD under the annual Hurricane Field Program together with NASA under CAMEX-4 conducted the COVES experiment in and around Hurricane Humberto over the Western Atlantic (Feuer et al. 2002). On the first day of the experiment, Humberto steadily strengthened to Category 2 intensity on the Saffir-Simpson scale; by the second day it had weakened to a minimal Category 1 storm. Five research aircraft were employed, including two NOAA WP-3Ds, the NASA DC-8, the NASA ER-2, and the NOAA Gulfstream-IV. Comprehensive data sets were compiled utilizing observations that originated from the research aircraft. They included airborne Doppler radar rainfall and wind data, meteorological measurements from over 120 GPS-dropsondes released from the aircraft each day, upper ocean thermal observations from numerous deployed Airborne Expendable Bathythermographs (AXBTs), ocean surface wind speed and wave height data from airborne passive micrwave radiometers and a scanning radar altimeter (SRA), and flight level meteorological and microphysical observations. By design a greater concentration of dropsondes were released within 150 km of the storm center than in the 150-400 km region in order to more effectively resolve the inner core structure.

MILESTONES:

REFERENCES:

Feuer, S.E., J.F. Gamache, M.L. Black, F.D. Marks, and J.B. Halverson. A multiple aircraft experiment in Hurricane Humberto (2001), Part I: Wind fields. Preprints, 25th Conf. Hurr. Trop. Meteor., San Diego, CA, Amer. Meteor. Soc., 206-207 2002.

Gao, Jidong, Xue, Ming, Shapiro, Alan, Droegemeier, Kelvin K. 1999: A Variational Method for the Analysis of Three-Dimensional Wind Fields from Two Doppler Radars. Mon. Wea. Rev., 127, 2128-2142.