Using EOF Analysis to Identify Important Surface Wind Patterns in Mountain Valleys

Journal Article · Thu Jul 01 04:00:00 EDT 2004 · Journal of Applied Meteorology

DOI:https://doi.org/10.1175/1520-0450(2004)043<0969:ueatii>2.0.co;2· OSTI ID:15020842

Ludwig, F. L.; Horel, John; Whiteman, C. David

Empirical orthogonal functions (EOF) have been determined for three wind data sets from stations in valleys south of the Great Salt Lake in Utah. Two of the data sets were for summer months, with individual days selected from the MesoWest archive to represent conditions conducive to well-developed thermally driven flows. The remaining data set was for the month of October 2000 and was derived from a combination of MesoWest data and data collected during intensive observation periods of the Vertical Transport and Mixing eXperiment (VTMX) conducted in the Salt Lake area in October 2000. This experiment investigated stable atmospheric conditions in the complex urban terrain around Salt Lake City, Utah. In all three data sets, the primary EOFs represented flows that were directed predominantly along valley axes and were caused by channeled or thermally driven flow. Diurnal variations in EOF intensity showed that thermal effects were the most common causal mechanism. These along-valley EOFs accounted for 43 to 58 percent of the variance in the wind component data sets (8 or 10 stations each). The second EOFs accounted for 13 to 18 percent of the variance. In the summer data sets, the second EOF appeared to represent day-night transition periods; there was evidence of side canyon flows and day-night transitional effects in the October data set. The EOF approach has promise for classifying wind patterns and selecting cases for simulation or for further detailed analysis.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 15020842
• Report Number(s): PNNL-SA-39628; KP1202010
• Journal Information: Journal of Applied Meteorology, Journal Name: Journal of Applied Meteorology Journal Issue: 7 Vol. 43; ISSN 0894-8763
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
COMPUTERIZED SIMULATION
DAILY VARIATIONS
FLOW MODELS
PATTERN RECOGNITION
TEMPERATURE DEPENDENCE
UTAH
VALLEYS
WIND