Ce. Konrad, The most extreme precipitation events over the eastern United States from 1950 to 1996: Considerations of scale, J HYDROMETE, 2(3), 2001, pp. 309-325
The intensity or magnitude of a given heavy precipitation event is typicall
y associated with the greatest point precipitation total. The scale or size
of the heavy precipitation region, however, is important because it affect
s the scale of the flooding potential (e.g., local- vs regional-scale basin
s). In this study, a heavy-rain climatological description is constructed t
hat identifies all precipitation events for the period of 1950-96 and estim
ates the heaviest mean 2-day precipitation totals over a range of spatial s
cales (i.e., circular regions from 2500 to 500 000 km(2)). Ranks of the mos
t extreme precipitation events are provided for four regions of the study a
rea for each of the 10 spatial scales. To develop the dataset, daily precip
itation totals from the cooperative observer network are spatially interpol
ated onto a finescale (10 km by 10 km) grid over the eastern two-thirds of
the United States. An automated algorithm is developed 1) to identify regio
ns displaying the greatest mean 2-day precipitation totals over each spatia
l scale and 2) to link nearby regions of different scales together to form
precipitation events. Precipitation events with regional recurrence interva
ls of approximately 1 yr or greater at each spatial scale are examined and
compared across four subregions. The geographical and seasonal distribution
s of these events are provided. The extreme events are also tied to the occ
urrence of tropical cyclones and 500-hPa cyclones. Secular trends are ident
ified in the frequency of extreme events over the different spatial scales.