#ENSO BOZEMAN DRIVER#

This is the first clear evidence that strong upwelling winds can depress local recruitment of.

Poorly constrained meteorological and hydrological data do not seem to explain fully these вЂњexcessвЂќ rivers changed seasonality in discharge, decreased storage and/or decreased evapotranspiration also may play important roles.ДЄbstract In this analysis, an atypical northward shift in the distribution of age-1 ocean shrimp (Pandalus jordani) recruits off Oregon in 20вЂ“2004 was linked to anomolously strong coastal upwelling winds off southern Oregon (42В°N latitude) in AprilвЂ“July of the year of larval release (tв€’1). A number of high-latitude and high-altitude rivers experienced increased discharge despite generally declining precipitation. Cumulative discharge from many mid-latitude rivers, in contrast, decreased by 60%, reflecting in large part impacts due to damming, irrigation and interbasin water transfers. Discharge trends for many rivers reflected mostly changes in precipitation, primarily in response to short- and longer-term atmosphericвЂ“oceanic signals with the notable exception of the Parana, Mississippi, Niger and Cunene rivers, few of these вЂњnormal' rivers experienced significant changes in either discharge or precipitation. We suggest that it may be coastal surface water temperature, perhaps combined with wind direction and intensity.Дuring the last half of the 20th century, cumulative annual discharge from 137 representative rivers (watershed areas ranging from 0.3 to 6300 Г— 103 km2) to the global ocean remained constant, although annual discharge from about one-third of these rivers changed by more than 30%.

#ENSO BOZEMAN DRIVER#

Clearly another climatic signal must be a major driver in precipitation and river runoff. As an extreme example, mean annual discharge of the Nehalem (Oregon) and Skagit (Washington) rivers is essentially the same during El Nino and La Nina years, as well as during cold and warm PDO years. While event discharge (defined as the top 1% daily discharges over the past 50 years) reflects the above climatic signals, mean annual discharges do not. These correlation coefficients, however, explain only a relatively small portion of the interannual variability. Central and northern Californian rivers represent a transition from southern to northern climates. Discharge of southern Californian rivers is positively correlated with El Nino and warm PDO, whereas northwest rivers are positively correlated with La Nina and cold PDO. River discharge of west coast rivers is strongly tied to both ENSO and PDO.

Enso bozeman