Ohio Winter Precipitation and Stream Flow Associations to Pacific Atmospheric and Oceanic Teleconnection Patterns
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Date
2004-06
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Abstract
The relationship between the Pacific/North American (PNA) atmospheric circulation teleconnection, equatorial Pacific sea surface temperature anomalies (SSTAs), and Ohio winter (DJF) precipitation and stream flow is described using data for 84 statewide climate stations and 29 rivers.
Maximum correlations between the PNA index (PNAI) and station precipitation reach r = -0.7 in southwestern Ohio (n = 53) and are as high as r = +0.6 (n = 104) using a proxy North Pacific index (NPI) comprised of sea level pressures. The Ohio winter precipitation and streamflow relationship with the PNAI and NPI is strongest in southern and southwestern Ohio, generally decreasing to non-significance over northern Ohio, and particularly the northeastern snow belt. In contrast, NiƱo 3.4 equatorial Pacific correlations reach r = 0.5 when SSTs precede winter by one month. Wettest (driest) Ohio winters occur during relatively zonal (meridional) flow, representing PNAI negative (positive) modes when north Pacific sea level pressure is anomalously high (low). Wet winters are characterized by a 500 hPa trough across the central US east of the Rockies, with surface cyclones and associated frontal activity traversing Ohio after originating in areas such as Colorado and the western Gulf of Mexico. When the meridional flow of the PNA positive mode occurs, Ohio winters are consistently drier than normal and stream flow is typically about 50% of the PNA wet winters. Much higher variability occurs during PNA negative mode winters; precipitation and stream flow are occasionally below normal, but more typically above normal with some extraordinarily wet winters.
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Author Institution: Dept of Geography, The Ohio State University
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Citation
The Ohio Journal of Science, v104, n3 (June, 2004), 51-59.