DOI: 10.1175/JCLI-D-11-00679.1
Scopus记录号: 2-s2.0-84867654794
论文题名: Assessing the influence of the MJO on strong precipitation events in subtropical, semi-arid north-central Chile (30°S)
作者: Juliá C. ; Rahn D.A. ; Rutllant J.A.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2012
卷: 25, 期: 20 起始页码: 7003
结束页码: 7013
语种: 英语
Scopus关键词: Intraseasonal variability
; Madden-Julian oscillation
; Seasonal forecasting
; South America
; Surface observation
; Atmospheric pressure
; Climate change
; Errors
; Precipitation (chemical)
; Precipitation (meteorology)
; Alarm systems
; Antarctic Oscillation
; climate prediction
; Madden-Julian oscillation
; precipitation (climatology)
; rainfall
; seasonal variation
; semiarid region
; Southern Oscillation
; subtropical region
; synoptic meteorology
; Chile
; Coquimbo
; Elqui Valley
; La Serena
英文摘要: Annual precipitation in subtropical, semiarid north-central Chile (308S) during rainy years comprises a few (3-5) strong events in the fall and winter, which are presumably modulated by the Madden-Julian oscillation (MJO). Precipitation from 1979-2009 was recorded daily at three stations along the Elqui Valley. The relationship between the MJO and precipitation is investigated from two perspectives: 1) examining a MJO index (MJOI) based on the actual precipitation events and 2) examining the likelihood of precipitation based on a favorable MJOI. About 80% of the strong precipitation events at the coast in La Serena are related to an active MJOnear the central equatorial Pacific. These events are often typified by broad, slow moving synoptic systems in phase with the MJO propagation. Blocking in the far southeast Pacific is associated with precipitation 75% of the time, while deep troughs make up the rest. A relationship between a MJOI and strong rainfall suggests that, though it could be used as a potential diagnostic, the number of cases where there is a favorable MJOI but no precipitation (i.e., false alarms) limits its utility. Additional criteria such as the Southern Oscillation (SO) and Antarctic Oscillation (AAO) phases were used to reject false alarms. Rejecting cases with positive values of the SO index reduced the number of false alarms from 70% to 58%, leaving about two false alarms for every correctly diagnosed event. The AAO index could not discriminate between false alarms and real cases. While a favorable MJOI increases the likelihood of precipitation in the Elqui Valley, false alarms remain problematic. © 2012 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/52210
Appears in Collections: 气候变化事实与影响
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作者单位: Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile; Departamento de Geofísica, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago, Chile
Recommended Citation:
Juliá C.,Rahn D.A.,Rutllant J.A.. Assessing the influence of the MJO on strong precipitation events in subtropical, semi-arid north-central Chile (30°S)[J]. Journal of Climate,2012-01-01,25(20)