hide
Free keywords:
-
Abstract:
Air pressure readings and their variations are commonly used to make
inferences about storm activity. More precisely, it is assumed that the
variation of annual and seasonal statistics of several pressure-based
proxies describes changes in the past storm climate qualitatively, an
assumption that has yet to be proven.
A systematic evaluation of the informational content of five
pressure-based proxies for storm activity based on single-station
observations of air pressure is presented. The number of deep lows,
lower percentiles of pressure, the frequency of absolute pressure
tendencies above certain thresholds, as well as mean values and high
percentiles of absolute pressure tendencies is examined. Such an
evaluation needs long and homogeneous records of wind speed, something
that is not available from observations. Consequently, the proxies are
examined by using datasets of ground-level wind speeds and air pressure
from the NCEP-driven and spectrally nudged regional model, REMO. The
proxies are gauged against the 95th and 99th percentile time series of
ground-level wind speeds to quantify the relation between pressure-based
proxies and storminess. These analyses rely on bootstrap and binomial
hypothesis testing. The analyses of single-station-based proxies
indicate that the proxies are generally linearly linked to storm
activity, and that absolute pressure tendencies have the highest
informational content. Further, it is investigated as to whether the
proxies have the potential for describing storminess over larger areas,
also with regard to surface conditions. It is found that absolute
pressure tendencies have improved informational value when describing
storm activity over larger areas, while low pressure readings do not
show improved informational value.
