Surface turbulent fluxes over pack ice inferred from TOVS observations

A one-dimensional, atmospheric boundary-layer model is coupled to a thermodynamic ice model to estimate the surface turbulent fluxes over thick sea ice. The principal forcing parameters in this time-dependent model are the air temperature, humidity, and wind speed at a specified level (either at 2 m or at 850 mb) and the down-welling surface radiative fluxes, The free parameters are the air temperature, humidity, and wind-speed profiles below the specified level, the surface skin temperature and ice-temperature profile, and the surface turbulent fluxes. The goal is to determine how well we can estimate the turbulent surface heat and momentum fluxes using forcing parameters from atmospheric temperatures and radiative fluxes retrieved Irom the TlROS-N Operational Vertical Sounder TOVS) data.Meteorological observations from the Lead Experiment (LeadEx, April 1992) ice camp are used to validate turbulent fluxes computed with the surface observations, and the results are used to compare with estimates based on radiosonde observations or with estimates based on TOVS data. We and that the TOVS-based estimates of the stress are significantly more accurate than those found with a constant geostrophic drag coefficient, with a rool mean square error about half as large. This improvement is due to stratification effects included in the boundary-layer model. The errors in the sensible heat flux estimates, however, are large compared Io the small mean values observed during the field experiment.

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Further Development of the Regional Boundary Layer Model to Study the Impacts of Greenery on the Urban Thermal Environment

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-14-0057.1 ◽

2015 ◽

Vol 54 (1) ◽

pp. 137-152 ◽

Cited By ~ 7

Author(s):

Jianbo Yang ◽

Hongnian Liu ◽

Jianning Sun ◽

Yan Zhu ◽

Xueyuan Wang ◽

...

Keyword(s):

Boundary Layer ◽

Air Temperature ◽

Thermal Environment ◽

Tree Planting ◽

Cooling Effect ◽

Layer Model ◽

Boundary Layer Model ◽

Urban Greenery ◽

Tree Coverage ◽

Regional Boundary

AbstractA forest canopy model is developed and coupled into the Regional Boundary Layer Model (RBLM) to fully consider the vertical structure of tree morphology. Instead of a slab surface model formerly used to represent trees in RBLM, the new version allows refinement of the radiation budgets as well as sensible and latent heat fluxes and, hence, more precise simulation of the thermal impacts of tree plantings on urban meteorological behavior. By applying this new version of RBLM, sensitivity tests are conducted to explore the potential impacts of different greenery scenarios on the thermal environment in an eastern Chinese city, Suzhou, during hot summer days. Greenings, both tree planting and grass surfacing, are beneficial in cooling the ambient air temperature. In general, tree planting is more beneficial than grass surfacing with the same coverage. In terms of surface energy balance, with tree coverage increasing from 0% to 20%, and then to 40%, the average surface net radiation fluxes at noon (1200 LST) are 591, 512, and 421 W m−2, respectively. Correspondingly, the Bowen ratio is reduced from 8.78 to 1.20 and then to 0.43 as result of the redistribution of solar energy absorbed at the ground. The cooling effect of trees is more significant at noontime and can remarkably lower the daily maximum air temperature in urban areas. The cooling effect of urban greenery increases with its coverage. Using the study results, a tree coverage of around 40% may be a feasible and optimized urban greenery scheme.

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CheapAML: A Simple, Atmospheric Boundary Layer Model for Use in Ocean-Only Model Calculations

Monthly Weather Review ◽

10.1175/mwr-d-11-00254.1 ◽

2013 ◽

Vol 141 (2) ◽

pp. 809-821 ◽

Cited By ~ 12

Author(s):

Bruno Deremble ◽

N. Wienders ◽

W. K. Dewar

Keyword(s):

Boundary Layer ◽

Atmospheric Boundary Layer ◽

Wind Field ◽

Turbulent Fluxes ◽

Test Cases ◽

Marine Atmospheric Boundary Layer ◽

Layer Model ◽

Global Modeling ◽

Model Calculations ◽

Radiative Fluxes

Abstract A model of the marine atmospheric boundary layer is developed for ocean-only modeling in order to better represent air–sea exchanges. This model computes the evolution of the atmospheric boundary layer temperature and humidity using a prescribed wind field. These quantities react to the underlying ocean through turbulent and radiative fluxes. With two examples, the authors illustrate that this formulation is accurate for regional and global modeling purposes and that turbulent fluxes are well reproduced in test cases when compared to reanalysis products. The model builds upon and is an extension of Seager et al.

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