Department of Meteorology
Montgomery Research Group
This page descibes the methodology behind the PREDICT field program. For weather products for 2010 storms, please go to the Storms 2010 page.
Recent years have seen several field campaigns aimed at understanding the dynamics of tropical cyclone formation. These include the Tropical Cloud Systems and Processes (TCSP) in 2005 (Halverson et al. 2007) and the NASA AMMA project in 2006. Adding in the results of earlier efforts such as the Tropical Experiment in Mexico (TEXMEX; Bister and Emanuel 1997, Raymond et al. 1998) and even serendipitous observations of the early development of hurricane Ophelia in RAINEX (Houze et al. 2006, 2009) and occasionally from reconnaissance aircraft (Reasor et al. 2005), and we have a collection of studies that have sampled pieces of a large and complex scientific puzzle. As discussed in DMW08, the puzzle begins with the formation of a tropical depression, a necessary meteorological precursor that results, in most cases, in the subsequent formation of a tropical cyclone.
So why should there be a new effort? (1) The problem of tropical depression formation remains unanswered and is one of the great remaining mysteries of the tropical atmosphere. Perhaps the greatest shortcoming of previous campaigns is the limited sampling, both in space and in time.(2) It is difficult to piece together snapshots of tropical disturbances taken at different times. “Genesis” (the formation of a tropical depression-strength vortex at sub-synoptic scales) often occurs between sampling times, or after disturbances move out of range.(3) There are very few observations of both precursors to genesis and the ensuing tropical cyclone formation process. The limited range of previous projects has also meant a limited phenomenological scope, regarding precursors to genesis and the multi-scale interactions needed for TC formation. We now know that synoptic-scale precursors take many forms (tropical waves, monsoon troughs, upper-tropospheric PV features, etc.). DMW08 argued that the genesis process itself should be relatively invariant on mesoscale and sub-synoptic scales in spite of these differences in synoptic precursor patterns. But we do not know if this is correct.(4) The marsupial paradigm of tropical cyclogenesis proposed by DMW08 embodies several new, unifying hypotheses that must be tested in order to confront the issues raised above.(5) Finally, the combination of technological resources at our disposal is unprecedented.
As discussed in DMW08 and the subsequent papers in 2009, a key ingredient in the marsupial paradigm is the role of rotating deep moist convection and how convective organization in a rotating environment differs from that of typical mesoscale convective systems in the tropics. Differences in cloud systems arising from the unique nature of the proto-vortex environment imply a different pathway of dynamical evolution than what might otherwise occur in the absence of this environment. The construction of a hurricane is a marvellous event, one that cannot be taken for granted in the current climate of Earth, nor in the perturbed climates to come. A unique cloud system structure and dynamical evolution, and a key role of precursor waves, contribute to this marvel in its early stages. The mesoscale aspects of this structure and evolution remain poorly understood.
To address limitations of previous campaigns, the proposed PRE-Depression Investigation of Cloud-systems in the Tropics (PREDICT) aims to dramatically increase the spatial and temporal sampling of tropical disturbances prior to, and during, genesis. The PREDICT experiment is envisioned as a close collaboration between the Unites States National Science Foundation (NSF), the National Oceanic and Atmospheric Administration (NOAA) and the Naval Postgraduate School in Monterey, California. The primary research tools needed are the NCAR G-V aircraft, with altitude and range advantages over previous aircraft, and two NOAA WP-3D aircraft each equipped with a tail Doppler radar, a lower fuselage (weather surveillance) radar, and the standard suite of flight-level and dropwindsonde observations that accompany normal hurricane and pre-hurricane reconnaissance. For the NCAR G-V aircraft, we propose to double-crew the aircraft for a portion of the field phase to allow sampling disturbances for as much as 16 out of 24 hours. The project will cover the majority of the Atlantic sector, including the Caribbean, and therefore will be poised to observe many forms of precursor disturbances and be positioned to uncover the common physical processes of genesis on the mesoscale. Finally, the project aims to fully integrate the plethora of satellite data and derived products now available, coordinating the aircraft missions to maximize the total data coverage and physical interpretation.
Download the Experimental Design Overview document for PREDICT 2010: Download [PDF]
Download the Scientific Program Overview document for PREDICT 2010: Download [PDF]
