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Observations of a two‐layer soil moisture influence on surface energy dynamics and planetary boundary layer characteristics in a semiarid shrubland
Author(s) -
SanchezMejia Zulia Mayari,
Papuga Shirley A.
Publication year - 2014
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 - 10.1002/2013wr014135
Subject(s) - water content , environmental science , planetary boundary layer , vegetation (pathology) , moisture , albedo (alchemy) , atmospheric sciences , soil science , boundary layer , hydrology (agriculture) , geology , meteorology , geography , medicine , art , physics , geotechnical engineering , pathology , performance art , thermodynamics , art history
We present an observational analysis examining soil moisture control on surface energy dynamics and planetary boundary layer characteristics. Understanding soil moisture control on land‐atmosphere interactions will become increasingly important as climate change continues to alter water availability. In this study, we analyzed 4 years of data from the Santa Rita Creosote Ameriflux site. We categorized our data independently in two ways: (1) wet or dry seasons and (2) one of the four cases within a two‐layer soil moisture framework for the root zone based on the presence or absence of moisture in shallow (0–20 cm) and deep (20–60 cm) soil layers. Using these categorizations, we quantified the soil moisture control on surface energy dynamics and planetary boundary layer characteristics using both average responses and linear regression. Our results highlight the importance of deep soil moisture in land‐atmosphere interactions. The presence of deep soil moisture decreased albedo by about 10%, and significant differences were observed in evaporative fraction even in the absence of shallow moisture. The planetary boundary layer height ( PBL h ) was largest when the whole soil profile was dry, decreasing by about 1 km when the whole profile was wet. Even when shallow moisture was absent but deep moisture was present the PBL h was significantly lower than when the entire profile was dry. The importance of deep moisture is likely site‐specific and modulated through vegetation. Therefore, understanding these relationships also provides important insights into feedbacks between vegetation and the hydrologic cycle and their consequent influence on the climate system.