Open AccessModeling the air‐sea feedback system of Madeira Island
Author(s) -
Pullen Julie,
Caldeira Rui,
Doyle James D.,
May Paul,
Tomé Ricardo
Publication year - 2017
Publication title -
journal of advances in modeling earth systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.03
H-Index - 58
ISSN - 1942-2466
DOI - 10.1002/2016ms000861
Subject(s) - advection , planetary boundary layer , wake , environmental science , atmosphere (unit) , diurnal cycle , sea surface temperature , boundary current , atmospheric sciences , atmospheric model , climatology , boundary layer , geology , ocean current , meteorology , oceanography , geography , aerospace engineering , physics , engineering , thermodynamics
A realistic nested data‐assimilating two‐way coupled ocean/atmosphere modeling study (highest resolution 2 km) of Madeira Island was conducted for June 2011, when conditions were favorable for atmospheric vortex shedding. The simulation's island lee region exhibited relatively cloud‐free conditions, promoting warmer ocean temperatures (∼2°C higher than adjacent waters). The model reasonably reproduced measured fields at 14 meteorological stations, and matched the dimensions and magnitude of the warm sea surface temperature (SST) wake imaged by satellite. The warm SSTs in the wake are shown to imprint onto the atmospheric boundary layer (ABL) over several diurnal cycles by modulating the ABL depth up to ∼200–500 m. The erosion and dissipation of the warm ocean wake overnight was aided by atmospheric drainage flow and offshore advection of cold air (ΔT = 2°C) that produced strong upward heat fluxes (∼50 W/m 2 sensible and ∼250 W/m 2 latent) on an episodic basis. Nevertheless, the warm wake was never entirely eroded at night due to the cumulative effect of the diurnal cycle. The spatial pattern of the diurnal warming varied day‐to‐day in location and extent. Significant mutual interaction of the oceanic and atmospheric boundary layers was diagnosed via fluxes and temperature cross sections and reinforced by sensitivity runs. The simulation produces for the first time the interactive nature of the ocean and atmosphere boundary layers in the warm wake region of an island with complex terrain.