Flux determination over a smooth surface under strongly unstable conditions

Sugita, Michiaki; Hiyama, Tetsuya; Endo, Noritaka; Tian, Shao-Fen

doi:10.1007/bf00708934

Cited by 14 publications

(4 citation statements)

References 12 publications

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“…Assuming that current parameterizations of canopy effects on the radiation balance and surface energy budget in land surface schemes are adequate, the ability of climate models to accurately predict such influences will rely heavily on suitable representation of surface characteristics (canopy architecture and albedo) of boreal regions prefire and postfire. For smooth surfaces, under strongly unstable conditions, the profile method tends to overestimate sensible heat fluxes [ Sugita et al , 1995]. Roughness lengths for heat and momentum directly affect sensible heat fluxes (and thus boundary layer development) and, through changes in the wind speed profile, fluxes of moisture and other scalars [ Holtslag and Ek , 1996].…”

Section: Discussionmentioning

confidence: 99%

Fire effects on net radiation and energy partitioning: Contrasting responses of tundra and boreal forest ecosystems

et al. 2005

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[1] The net radiation available to drive surface-atmosphere exchange is strongly influenced by albedo and surface temperature. Tower-based microclimatic and eddy covariance measurements in typical Alaskan black spruce and tundra ecosystems before and immediately after fire indicated a 10% decrease in net radiation over the burned spruce stand but a 12% increase in net radiation over the burned tundra surface. In both cases, there was increased partitioning of net radiation into sensible heat flux. In terms of absolute fluxes, however, fire increased average sensible heating over tundra by $50 W m À2 but caused little change in average sensible heat flux over the black spruce forest. This difference in fire effects occurred because fire altered the canopy characteristics (including surface roughness) more strongly in the forest than in the tundra, leading to a greater reduction in surface-atmosphere coupling over the forest.

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Section: Discussionmentioning

confidence: 99%

Fire effects on net radiation and energy partitioning: Contrasting responses of tundra and boreal forest ecosystems

et al. 2005

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“…Re u z     (Nikuradse, 1933, Sugita et al, 1995, so that only rough surface observations were chosen. The value of a = 0.032 clearly falls within the range of previous proposals of a = 0.012 -0.035 (e.g., Garratt 1992) and was used for our analysis, and for the discussion provided below, although the value is higher than the commonly assumed value of a = 0.011 used for the ocean (e.g., Fairall et al 1996Fairall et al , 2003.…”

Section: Wavesmentioning

confidence: 99%

Drag and Bulk Transfer Coefficients Over Water Surfaces in Light Winds

Wei

Miyano

Sugita

2016

Boundary-Layer Meteorol

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The drag coefficient (C D), experimentally determined from observed wind speed and surface stress, has been reported to increase in the low wind-speed range (< 3 m s −1) as wind speed becomes smaller. However, until now, the exact causes for its occurrence have not been determined. Here, possible causes for increased C D values in near-calm conditions are examined using high quality datasets selected from three-year continuous measurements obtained from the centre of Lake Kasumigaura, the second largest lake in Japan. Based on our analysis, suggested causes including (i) measurement errors, (ii) lake currents, (iii) capillary waves, (iv) the possibility of a measurement height within the interfacial/transition sublayer, and (v) a possible mismatch in the representative time scale used for mean and covariance averaging, are not considered major factors. The use of vector-averaged, instead of scalar-averaged, wind speeds and the presence of waves only partially explain the increase in C D under light winds. A small increase in turbulence kinetic energy due to buoyant production at low wind speeds is identified as the likely major cause for this increase in C D in the unstable atmosphere dominant over inland water surfaces.

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“…The form was used of the function for C h of Brutsaert (1992) obtained using both of the proposals of Kader and Yaglöm (1990), and the analysis of Hög-ström (1988) for the atmospheric conditions, since the result of Sugita et al (1995) showed that Brutsaert's function was applicable under strong unstable stability conditions. The general form of C h can be written as …”

Section: Appendix a Footprint Calculationmentioning

confidence: 99%

Observations of Energy Fluxes and Evapotranspiration over Terrestrial Complex Land Covers in the Tropical Monsoon Environment

Toda¹,

Nishida

Ohte

et al. 2002

Journal of the Meteorological Society of Japan

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The surface energy flux balance and total evapotranspiration were estimated using the eddy correlation, and bandpass covariance technique over a tropical monsoon environment within the framework of GEWEX (Global Energy and Water cycle Experiment) Asian Monsoon Experiment (GAME). The aim of this present study is to obtain information on the seasonal variation of heat and water vapor exchanges between the atmosphere and terrestrial land cover (complex area) in tropical monsoon environment.The result indicated the daily integrated values of net radiation, sensible heat, latent heat and ground heat flux during the observation period from July 1998 to February 1999 were 10.76 MJ m À2 , 2.32 MJ m À2 , 5.18 MJ m À2 and 0.03 MJ m À2 , respectively. Sensible and latent heat fluxes were the dominant energy partitioning components throughout the year. The seasonal difference in surface fluxes between wet and dry seasons was seen, and the latent heat flux was dominant in the monsoon, corresponding with the increase of specific humidity after frequent precipitation. Whereas the sensible heat flux increased as the surface temperature increased in the absence of rainfall during the dry season. However, the closure of energy balance remained unresolved as with the foregoing experimental studies. The estimated amount to evapotranspiration was 526 mm versus 641 mm of actual precipitation, and accounted for about 80% of the precipitation during this period.

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Flux determination over a smooth surface under strongly unstable conditions

Cited by 14 publications

References 12 publications

Fire effects on net radiation and energy partitioning: Contrasting responses of tundra and boreal forest ecosystems

Fire effects on net radiation and energy partitioning: Contrasting responses of tundra and boreal forest ecosystems

Drag and Bulk Transfer Coefficients Over Water Surfaces in Light Winds

Observations of Energy Fluxes and Evapotranspiration over Terrestrial Complex Land Covers in the Tropical Monsoon Environment

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