Wind stress, cumulative wind stress, and spring transition dates:
S. D. Pierce and
J. A. Barth
data products for Oregon upwelling-related research
College of Earth, Ocean, & Atmospheric
Cumulative wind stresses relevant for Oregon coastal upwelling research are publicly
available here. These are similar to the cumulative wind stress
products used in Barth et al. (2007) and Pierce et al. (2006);
some details differ.
Alongshore wind stress cumulative from the spring transition represents energy input
into the upwelling system over the course of each season. This has
been found to
be strongly correlated with a number of different upwelling metrics
(Pierce et al., 2006), eg. NH-line surface-layer temperature (0-30m).
Wind stress here is derived from observed winds
at Newport, Oregon, using the method of Large and Pond (1981).
The hourly data are low-pass filtered to remove diurnal variations.
The spring and fall transitions (Huyer et al., 1979) are estimated
for each year from the alongshore wind stress record, using a CUSUM
algorithm for change-point detection (Page, 1954; Gustafsson, 2000).
The significance (95%) of these two mean-shift change-points within
each year's time series is confirmed using bootstrapping, as suggested
by Hinkley and Schechtman (1987).
We hope that researchers will find it useful to compare their own
upwelling-related data to the general development of upwelling
represented by this cumulative wind stress product. Plots and data
access are available via the links to the left.
Supported by the National Science Foundation (OCE-0435619).
Barth, J. A., B. A. Menge, J. Lubchenco, F. Chan, J. M. Bane, A. R.
M. A. McManus, K. J. Nielsen, S. D. Pierce, and L. Washburn
Delayed upwelling alters nearshore coastal ocean ecosystems in the northern
Proceedings of the National Academy of Sciences, 104,
Gustafsson, F. (2000) Adaptive filtering and change detection,
Hinkley, D. and E. Schechtman (1987) Conditional bootstrap methods in the
mean-shift model. Biometrika, 74, 85-93.
Huyer, A., E. J. C. Sobey, and R. L. Smith (1979) The spring transition
in currents over the Oregon continental shelf. J. Geophys. Res., 84,
Large, W. G. and S. Pond (1981) Open ocean momentum flux measurements
in moderate-to-strong winds. J. Phys. Oc., 11, 324-336.
Page, E. S. (1954) Continuous inspection schemes. Biometrika, 41,
Pierce, S. D., J. A. Barth, R. E. Thomas, and G. W. Fleischer (2006)
Anomalously warm July 2005 in the northern California
context and the significance of cumulative wind stress,
Geophys. Res. Letters, 33,