25 research outputs found
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Sensitivity of a Continuum-Scale Porous Media Heat and Mass Transfer Model to the Spatial-Discretization Length-Scale of Applied Atmospheric Forcing Data
Fundamental process understanding and description of heat, mass, and momentum exchanges across the land-atmosphere interface in model boundary forcing parameterizations is critical to the simulation of near-surface soil moisture dynamics (e.g., bare-soil evaporation). This study explores the sensitivity of a continuum-scale porous media heat and mass transfer model to the spatial-discretization length-scales (i.e., spatial-resolution) of near-surface atmospheric data; the goal is to determine how much data are needed to force the model and adequately capture evaporative water losses and subsurface state variable distributions. The requisite atmospheric forcing data were taken from the high-resolution, precision bare-soil evaporation experiments of Trautz et al. (2018, https://doi.org/10.1029/2018WR023102). Simulation results demonstrated that shallow subsurface mass and heat transfer dynamics can be adequately captured with forcing data averaged over large length-scales, or a minimal number of measurements, provided that soil conditions are properly described. The soil moisture spatial distributions were found to be insensitive to horizontal variations in the forcing data. The model failed to capture small-scale trends observed experimentally; this did not impact the accuracy of total evaporative water loss estimates however. These results indicate that in future physical experimental efforts conducted at 1–10-m length-scales, there is no need to focus on the generation of high-spatial resolution atmospheric measurements—time and effort would be better spent in characterizing soil conditions and properties. Even though a theoretical foundation was not provided to directly extrapolate this work to the field scale, these findings have practical value in designing field data collection strategies
Recommended from our members
Sensitivity of a Continuum-Scale Porous Media Heat and Mass Transfer Model to the Spatial-Discretization Length-Scale of Applied Atmospheric Forcing Data
Fundamental process understanding and description of heat, mass, and momentum exchanges across the land-atmosphere interface in model boundary forcing parameterizations is critical to the simulation of near-surface soil moisture dynamics (e.g., bare-soil evaporation). This study explores the sensitivity of a continuum-scale porous media heat and mass transfer model to the spatial-discretization length-scales (i.e., spatial-resolution) of near-surface atmospheric data; the goal is to determine how much data are needed to force the model and adequately capture evaporative water losses and subsurface state variable distributions. The requisite atmospheric forcing data were taken from the high-resolution, precision bare-soil evaporation experiments of Trautz et al. (2018, https://doi.org/10.1029/2018WR023102). Simulation results demonstrated that shallow subsurface mass and heat transfer dynamics can be adequately captured with forcing data averaged over large length-scales, or a minimal number of measurements, provided that soil conditions are properly described. The soil moisture spatial distributions were found to be insensitive to horizontal variations in the forcing data. The model failed to capture small-scale trends observed experimentally; this did not impact the accuracy of total evaporative water loss estimates however. These results indicate that in future physical experimental efforts conducted at 1–10-m length-scales, there is no need to focus on the generation of high-spatial resolution atmospheric measurements—time and effort would be better spent in characterizing soil conditions and properties. Even though a theoretical foundation was not provided to directly extrapolate this work to the field scale, these findings have practical value in designing field data collection strategies
Complete surgical resolution of bilateral total opthalmoplegia without visual field defect in an acromegalic patient presented with pituitary apoplexy.
Pituitary apoplexy (PA), which is one of the most serious life-threatening complications of pituitary adenoma, is characterized by abrupt onset of headache, nausea, vomiting, visual disturbances and oculomotor paresis. Combination of oculomotor cranial nerve paralysis with normal visual fields is very rare in PA. We report a 60-year-old acromegalic mail presented with panhypopituitarism and bilateral total opthalmoplegia without a visual field defect. At initial evaluation his clinical findings were compatible with adrenal crisis and eye examination revealed total opthalmoplegia, bilateral ptosis and normal vision. MRI showed a large heterogeneous mass in the pituitary fossa. Although clinical findings due to adrenal crisis improved after glucocorticoid therapy there was no improvement in opthalmoplegia and ptosis. The patient underwent transsphenoidal excision of the pituitary mass. Histological examination revealed all adenoma with large areas of hemorrhagic infarction and most of the cells were positive for GH in immunohistochemical analysis. Although opthalmoplegia was severe at presentation, total recovery was achieved 3 months after transsphenoidal surgery. Therefore the presented case clearly demonstrates that opthalmoplegia without a visual field defect due to PA has a good prognosis and early diagnosis and treatment including surgical decompression are crucially important