| Popis: |
The El Niño Southern Oscillation (ENSO) teleconnection pattern drives interannual changes in winter precipitation across western North America, but these effects are entangled with orographic effects, caused by mountainous terrain, and long-term climate trends. This study employs a novel, spatially distributed non-linear spline model to isolate ENSO impacts from these other factors. We find that topography exaggerates the underlying effect of ENSO, driving larger precipitation changes at high elevations along western slopes. Further, we detected a north-south precipitation dipole, which exhibited incremental ENSO effects in the southern region, but more binary effects in the north. Spatial extents for positive and negative ENSO phases also varied based on topography. Confirmation of precipitation lapse rates and multi-decadal precipitation trends provides greater confidence in disentangling the ENSO signal. Ultimately, these results provide greater nuance regarding ENSO effects on winter precipitation, which is critical for domestic water supplies, ecological flows, and agriculture. |
