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Seasonal long‐term persistence in radar precipitation in complex terrain
Author(s) -
Savina Maurizio,
Molnar Peter,
Burlando Paolo
Publication year - 2011
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2010wr010170
Subject(s) - terrain , precipitation , term (time) , persistence (discontinuity) , radar , environmental science , climatology , meteorology , remote sensing , geology , geography , computer science , cartography , geotechnical engineering , telecommunications , physics , quantum mechanics
Precipitation in complex terrain is subject to orographic enhancement which leads to identifiable signatures in the space‐time precipitation distribution over the long term, for instance the presence of long‐term persistence. Here we quantify long‐term persistence by the scaling exponent H of the increase in the spatial variance of accumulated precipitation with time from high resolution radar data over a 2 year period in a section of the Swiss‐Italian Alps with relief greater than 4000 m. We find that the long‐term persistence signal is strong and seasonal with mean H = 0.87 – 0.99 in the cold season (autumn‐winter), when stratiform precipitation is dominant, and H = 0.73 – 0.81 in the warm season (spring‐summer), when convective events are dominant. H is also significantly correlated with mean altitude and surface variance, suggesting that singularities in the deposition process are partly driven by topography. The correlation is negative in the warm season and positive in the cold season, indicating the different physical origin of precipitation formation, atmospheric stability, and orographic effects in those seasons. By analyzing the binary precipitation occurrence process, we find that a large part of the long‐term persistence signal comes from the space‐time distribution of precipitation occurrence and clustering, regardless of precipitation intensity.