NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Terral De Vicuna, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit TreesThe terral de Vicuña is a warm and dry wind that flows down the Elqui Valley in north-central Chile typically at dawn and early morning. Given that most terral episodes occur in austral winter when chill accumulation by deciduous fruit trees proceeds, negative effects on agriculture may be expected. During 11 (2004-14) winters a meteorological characterization of terral winds and the assessment of their impact on chill accumulation, by the modified Utah Model and the Dynamic Model, were performed. Within this period, 67 terral days (TD) were identified as those in which nighttime to early morning wind direction and speed, air temperature, and relative humidity reached defined thresholds on an hourly basis (terral hours). Most frequent TD featured 6-9 consecutive terral hours; duration is considered here as a proxy for their intensity. Synoptic-scale meteorological analysis shows that 65% of moderate and strong terral events develop as a cold, migratory anticyclone drifts poleward of the study area, coinciding with the onset of a midtropospheric ridge over central Chile, bringing southwest winds on top of the Andes (approximately 500-hPa level). The remaining 35% are either associated with 500-hPa easterlies (foehn like), with prefrontal conditions ahead of a trough driving northwest 500-hPa winds, or with transitional 500-hPa westerlies.Assessments of chill accumulation during TD show that, although present average and cold winter conditions do not represent a major TD hazard to local agriculture, lower chill accumulation associated with anomalously high nocturnal temperatures could be significantly more important during present and future warmer winters.
Document ID
20160007480
Document Type
Reprint (Version printed in journal)
Authors
Montes, Carlo (Universities Space Research Association United States)
Rutllant, Jose A. (Universidad de La Serena Santiago, Chile)
Aguirre, Anita (Universidad de Aconcagua La Serena, Chile)
Bascunan-Godoy, Luisa (Universidad de La Serena Santiago, Chile)
Julia, Cristobal (Universidad de La Serena Santiago, Chile)
Date Acquired
June 13, 2016
Publication Date
May 6, 2016
Publication Information
Publication: Journal of Applied Meteorology and Climatology
Volume: 55
Issue: 5
ISSN: 1558-8424
Subject Category
Meteorology and Climatology
Report/Patent Number
GSFC-E-DAA-TN32579
Funding Number(s)
CONTRACT_GRANT: NNH15CO48B
Distribution Limits
Public
Copyright
Other
Keywords
agriculture
cooling
morning
drying
winter
Chile