Sensible Heat Flux-Radiometric Surface Temperature Relationship for Eight Semiarid Areas

Sensible heat exchange has important consequences for urban meteorology and related applications. Directional radiometric surface temperatures of urban canopies observed by remote sensing platforms have the potential to inform estimations of urban sensible heat flux. An imaging radiometer viewing the surface from nadir cannot capture the complete urban surface temperature, which is defined as the mean surface temperature over all urban facets in three dimensions, which includes building wall surface temperatures and requires an estimation of urban sensible heat flux. In this study, a numerical microclimate model, Temperatures of Urban Facets in 3-D (TUF-3D), was used to model sensible heat flux as well as radiometric and complete surface temperatures. Model data were applied to parameterize an effective resistance for the calculation of urban sensible heat flux from the radiometric (nadir view) surface temperature. The results showed that sensible heat flux was overestimated during daytime when the radiometric surface temperature was used without the effective resistance that accounts for the impact of wall surface temperature on heat flux. Parameterization of this additional resistance enabled reasonably accurate estimates of urban sensible heat flux from the radiometric surface temperature.

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Evaluation of functional properties of various types of vegetation cover using remotely sensed data analysis

Soil and Water Research ◽

10.17221/480-swr ◽

2010 ◽

Vol 4 (Special Issue 2) ◽

pp. S49-S58 ◽

Cited By ~ 4

Author(s):

J. Brom ◽

J. Procházka ◽

A. Rejšková

Keyword(s):

Heat Flux ◽

Surface Temperature ◽

Latent Heat ◽

Latent Heat Flux ◽

Land Surface ◽

Hydrological Cycle ◽

Sensible Heat Flux ◽

Sensible Heat ◽

Remotely Sensed Data ◽

Mean Values

The dissipation of solar energy and consequently the formation of the hydrological cycle are largely dependent on the structural and optical characteristics of the land surface. In our study, we selected seven units with different types of vegetation in the Mlýnský and Horský catchments (South-Eastern part of the Šumava Mountains, Czech Republic) for the assessment of the differences in their functioning expressed through the surface temperature, humidity, and energy dissipation. For our analyses, we used Landsat 5 TM satellite data from June 25<SUP>th</SUP>, 2008. The results showed that the microclimatic characteristics and energy fluxes varied in different units according to their vegetation characteristics. A cluster analysis of the mean values was used to divide the vegetation units into groups according to their functional characteristics. The mown meadows were characterised by the highest surface temperature and sensible heat flux and the lowest humidity and latent heat flux. On the contrary, the lowest surface temperature and sensible heat flux and the highest humidity and latent heat flux were found in the forest. Our results showed that the climatic and energetic features of the land surface are related to the type of vegetation. We state that the spatial distribution of different vegetation units and the amount of biomass are crucial variables influencing the functioning of the landscape.

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Estimation of Sensible Heat Flux from Surface Temperature Wave and One-Time-of-Day Air Temperature Observation

Boundary-Layer Meteorology ◽

10.1023/a:1000659320836 ◽

1998 ◽

Vol 86 (2) ◽

pp. 193-232 ◽

Cited By ~ 8

Author(s):

K. Blümel

Keyword(s):

Heat Flux ◽

Surface Temperature ◽

Air Temperature ◽

Sensible Heat Flux ◽

Time Of Day ◽

Temperature Wave ◽

Sensible Heat ◽

Temperature Observation

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Sensible Heat Flux in Near-Neutral Conditions over the Sea

Journal of Physical Oceanography ◽

10.1175/jpo-d-11-0186.1 ◽

2012 ◽

Vol 42 (7) ◽

pp. 1134-1142 ◽

Cited By ~ 10

Author(s):

L. Mahrt ◽

Dean Vickers ◽

Edgar L Andreas ◽

Djamal Khelif

Keyword(s):

Heat Flux ◽

Wind Speed ◽

Surface Temperature ◽

Sensible Heat Flux ◽

Sea Surface ◽

Sensible Heat ◽

Stable Conditions ◽

Weakly Stable ◽

Weak Winds ◽

Neutral Conditions

Abstract The variation of the sea surface sensible heat flux is investigated using data from the Gulf of Tehuantepec Experiment (GOTEX) and from eight additional aircraft datasets representing a variety of surface conditions. This analysis focuses on near-neutral conditions because these conditions are common over the sea and are normally neglected, partly because of uncertain reliability of measurements of the small air–sea temperature difference. For all of the datasets, upward heat flux is observed for slightly stable conditions. The frequency of this “countergradient” heat flux increases with increasing wind speed and is possibly related to sea spray or microscale variations of surface temperature on the wave scale. Upward area-averaged sensible heat flux for slightly stable conditions can also be generated by mesoscale heterogeneity of the sea surface temperature (SST). Significant measurement errors cannot be ruled out. The countergradient heat flux for weakly stable conditions is least systematic for weaker winds, even though it occurs with weak winds in all of the datasets. In an effort to reduce offset errors and different SST processing and calibration procedures among field programs, the authors adjusted the SST in each field program to minimize the countergradient flux for weak winds. With or without this adjustment for the combined dataset, the extent of the upward heat flux for weakly stable conditions increases with increasing wind speed.

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