|NOAA/National Severe Storms Laboratory|
November 18-19, 1997, Norman OK
Opening Remarks (Schneider)
A. Goals for the meeting
Presentation of Hypotheses (moderated by Rasmussen, Ziegler, and Schneider)
Candidate Experiment Designs (moderated by Rasmussen)
Observational resource requirements (moderated by Ziegler) Each presenter to define the following:
A. What resources will be needed?
Discussion of experiment timetable (moderated by Schneider)
A. Competing field projects?
A. Topics and concerns not yet addressed.
Roger Wakimoto (UCLA): 1 hypothesis
SPECIAL MESOSCALE FACILITIES REPRESENTATIVES:
Josh Wurman (OU/SOM): DOW radars
OTHER FACILITIES REPRESENTATIVES:
Vince Wong (CAPS): ARPS model
OTHER PARTICIPANTS AND OBSERVERS
Meeting Introduction (by J. Schneider)
Goals for the meeting:
Philosophy of TIMEX Planning:
We're taking the VORTEX approach a bit further, in a direction we believe
will improve our chances of:
- clear link between proposed activities and gain in knowledge;
- requires a lot of thinking up front.
Outline of philosophy:
My own vision continues to evolve with discussion. Instead of a single effort, Iím beginning to think in terms of a continuing series of linked efforts. The collection of hypotheses will grow (see Figure 1) and each will evolve with development of the experiment designs and discussion. Hypotheses with identical or overlapping observational requirements should be fielded simultaneously (for example, Hyp. B, D, and E might be tested together). Lessons learned from early field efforts will generate revised (and better) hypotheses. We plan to use a web page to act as virtual meeting room for discussion and planning, and to provide support during proposal writing.
- just convective initiation
TIMEx Field Area:
Generally, the degree of interest was even higher than we had expected. It is obvious that the general problem of convective initiation is quite complex, and poorly understood. This relative immaturity of understanding makes it difficult to phrase good testable hypotheses. As expected, there was a large variety in development of the presented hypotheses and related experiment plans. Plans from PIs with related field work tended to be focused on one or more specific aspects of candidate initiation processes, and were usually more advanced. Proposed locations to test this first generation of hypotheses tended to be in the Southern Great Plains, west of the tree line. This was primarily the result of the density of observing systems in this region, and challenges of observing surface-based initiation processes. It was broadly acknowledged that similar investigations may be required for regions with different climates and dominant initiation mechanisms, but none are currently expressed as hypotheses.
There was also a fair amount of resistance expressed on the first day relative to our hypothesis-based approach. Not all who are interested in the subject of convective initiation are prepared to tackle the problem within this framework. Participation in TIMEx is completely voluntary, and we welcome all who are willing to collaborate. Otherwise, we expect individual scientists to continue to pursue their goals in the manner they deem best outside of TIMEx.
In the process of discussion, several considerations became clear. First, the hypotheses posted and shared to date break down roughly into two kinds: elevated initiation processes (e.g., related to LLJ dynamics); and surface-based initiation processes (e.g., dry lines, outflow boundaries). The logistical and observational challenges involved in testing hypotheses are quite different for the two groups.
For elevated initiation processes, it appeared that some research could be performed immediately using either archived data, or operational and research network data. Testing of other hypotheses would require directed programs using existing instrument systems. Coordination and logistics would be quite similar to that of previous field programs (i.e., no new paradigms were required). For these hypotheses, the draft timeline for operations was reasonable.
The heavier demands arose relative to hypotheses on surface-based initiation. A number of scientists with related field experience presented strong arguments articulating a need to observe the evolution of the 3-D water vapor field, analagous to our ability to observe the wind field (e.g., portable scanning Doppler radars). Further, observation of moving surface boundaries presents an entirely different set of coordination and logistical challenges, of a higher degree of difficulty than has been previously managed (even in VORTEX). For these hypotheses, field operations will depend on developing:
- the required observational systems;
With these points in mind, it wasnít clear whether the draft timeline was reasonable or not. Presentations on existing and possible observing systems were tantalizing (especially water vapor DIAL and mobile Raman lidar systems), but did not resolve the basic question of whether systems capable of observing the spatially and temporally complex water vapor field near the surface would be available. Interested PIs left the meeting with an agenda to explore and define the observational opportunities and challenges related to surface-based initiation.