Connectivity between Historical Great Basin Precipitation and Pacific Ocean Variability A CMIP5 Model Evaluation

• Published in: Journal of climate Vol. 28; no. 15; pp. 6096 - 6112
• Main Authors: Smith, Kimberly, Strong, Courtenay, Wang, Shih-Yu
• Format: Journal Article
• Language: English
• Published: Boston American Meteorological Society 01.08.2015
• Subjects: 20th century; Atmospheric models; Climate; Climate change; Climate models; Correlations; Drought; El Nino; El Nino phenomena; El Nino-Southern Oscillation event; Evaluation; Freshwater; Global climate models; Hydrology; Intercomparison; Lakes; Marine; Meteorology; Modeling; Modelling; Oceans; Pacific Decadal Oscillation; Precipitation; Sea surface; Sea surface temperature; Southern Oscillation; Spatial models; Studies; Surface temperature; Time; Variability; Water management; Watersheds; United States > US; Pacific Ocean; Wasatch Range; Great Salt Lake; Utah; Great Basin; USA, Utah, Great Salt L; USA, Great Basin; USA; IN, North Pacific
• ISSN: 0894-8755; 1520-0442
• DOI: 10.1175/JCLI-D-14-00488.1

The eastern Great Basin (GB) in the western United States is strongly affected by droughts that influence water management decisions. Precipitation that falls in the GB, particularly in the Great Salt Lake (GSL) basin encompassed by the GB, provides water for millions of people living along the Wasatch Front Range. Western U.S. precipitation is known to be influenced by El Niño–Southern Oscillation (ENSO) as well as the Pacific decadal oscillation (PDO) in the North Pacific. Historical connectivity between GB precipitation and Pacific Ocean sea surface temperatures (SSTs) on interannual to multidecadal time scales is evaluated for 20 models that participated in phase 5 of the Coupled Model Intercomparison Project (CMIP5). While the majority of the models had realistic ENSO and PDO spatial patterns in the SSTs, the simulated influence of these two modes on GB precipitation tended to be too strong for ENSO and too weak for PDO. Few models captured the connectivity at a quasi-decadal period influenced by the transition phase of the Pacific quasi-decadal oscillation (QDO; a recently identified climate mode that influences GB precipitation). Some of the discrepancies appear to stem from models not capturing the observed tendency for the PDO to modulate the sign of the ENSO–GB precipitation teleconnection. Of all of the models, CCSM4 most consistently captured observed connections between Pacific SST variability and GB precipitation on the examined time scales.