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600
Broadband Instruments in the Field
Future
Commitments
500
Series1
400
Number of Instruments
300
200
100
0
Figure 38. History of the short-period instrument pool. The reduction
in short-period stations between 1995 and 2000 reflects retirement of
three-channel, controlled-source experiments that were replaced by
the TEXAN instruments in 2000.
Overall, new projects each year have remained constant
while the size and duration (and number of PIs) for a typical
experiment continues to grow. In the past, PASSCAL
has been able to manage these trends with an increasing
yearly inventory (Figure 38). If the total equipment inventory
reaches a stable level, the net effect will manifest itself
predictably into longer wait times for instruments. This
trend can be seen in Figures 39 and 40, where the cumulative
number of experiments and future equipment requests are
plotted versus the total inventory of equipment.
Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan- Jan-
90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10
Figure 39. PASSCAL broadband experiment history. Histogram of
all experiments through time plotted as a total of stations. Current
broadband inventory is approximately 460 sensors. Average wait time
for equipment has remained constant at approximately 2.5 years.
Actual experiments are plotted before the current time, equipment
requests after 2007.
available to fund field programs. Indirectly, the pressure
of wait times may also influence the number of proposals
submitted. A reasonable delay between the funding decision
and the start of field programs can sometimes be an
advantage in planning and logistical preparation, but significant
delays are problematic, especially for young faculty,
students, and postdocs.
PASSCAL Broadband Experiments
PASSCAL Broadband Experiments
The “wait time” for instruments—the time
between NSF’s or some other agency’s decision
to fund a proposal and when the full
complement of instruments are available for
deployment—has been a constant source of
concern for the user community. As noted
above, in spite of increasing numbers of
instruments, the general growth in experiment
size has meant that the broadband pool
remains in continual use—and there has not
been a decrease in wait time. For most of
the lifetime of PASSCAL, the wait time has
remained at 2–2.5 years. The length of the
wait time depends on a complex interaction
among the number of instruments available,
the desired size of arrays, the number of
proposals funded, and the level of resources
Number of Instruments
Figure 40. Time history of PASSCAL broadband experiments. Each experiment is one
line. The earliest experiments are in the front; recent and proposed experiments are
in the back. The size of each box shows experiment duration (length on the time axis)
and number of instruments (vertical axis). The trend toward longer experiments (wider
boxes) with more instruments (higher boxes) is clearly seen.
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