Linking hydrological variations at local scales to regional climatic
teleconnection patterns
Abstract
Interactions between the land surface and the atmosphere play essential
roles in hydrological variations at local scales. Variations of regional
climate patterns over preceding years have key effects on the seasonal
water and moisture conditions in the following year. The linkage between
regional climate and local hydrology is challenging due to scale
differences, both spatially and temporally. In this study, multiple
hydroclimatic phases were identified to relate climatic teleconnection
patterns to hydrological processes in a small headwater basin within
Reynolds Creek Experiment Watershed, Idaho, USA. A singular spectrum
analysis and a combination of hydrological observations and outputs from
a physically based hydrological model were used for this purpose.
Results showed that a positive phase of North Atlantic Oscillation (NAO)
is more influential than a positive phase of the Pacific North American
(PNA) pattern on the observed annual runoff and the modeled rain on snow
runoff in the study area. Specifically, we found a 43% and 26% shift
below normal in annual runoff and rain on snow runoff from NAO and a
29% and 9% below normal from PNA. More frequent rain on snow events
were observed under a positive phase of Antarctic Oscillation, leading
to a 45% increase in the rain on snow runoff, which accounts for
one-third of the mean annual runoff. A high runoff-to-precipitation
ratio was observed in the study area under negative phases of Arctic
Oscillation and Sea Surface Temperature in the Niño 3.4 region of the
Equatorial Pacific Ocean. A switch in the phase of the teleconnection
patterns of NAO and PNA in 2012 was concomitant with a transition from
wet to dry conditions in the basin, suggesting the importance of the
regional teleconnections in affecting snow and runoff regimes at local
scales. The identified hydroclimatic phases can be implemented in
operational models to improve uncertainties in hydrological forecasts,
climate projections, and water resources planning.