Comparison of latent and sensible heat fluxes over boreal lakes with concurrent fluxes over a forest: implications for regional averaging

Venäläinen, Ari; Frech, Michael; Heikinheimo, Martti; Grelle, Achim

doi:10.1016/s0168-1923(99)00100-8

Cited by 41 publications

(30 citation statements)

References 14 publications

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“…Such difference must be associated to the flooded Pantanal's differentiated behavior in night period, as discussed on [38], on wh ich flooded Pantanal's NBL is mo re turbulent than NBL in dry period. This difference is possibly associated to the mechanism described by [39,40], in wh ich water body causes heat absorption during the day and acts as heat source during the night. Therefore, flooded Pantanal shows such characteristics, allo wing this observed energy distribution in small length scales.…”

Section: Intensification and Spectral Peak Shift Induced Bymentioning

confidence: 98%

“…Beyond these physically relevant aspects, others were also highlighted in study of reference [40], regarding the peculiarities of surface energy balance in such conditions. In addition to water having a high heat capacity, energy exchange between lake surface and its deeper water layers is more effective than that between the surface and deeper soil layers.…”

Section: Effect Of Modification Of Surface Roughnessmentioning

confidence: 99%

“…It is true that they present mult iple d imensions, though is not known fro m art icle in literature that statistically approaches its distribution. However, experimental sites located in landscapes where exists lakes with several dimensions had already been object of study [40]. As the authors say, the properties of these lakes differ fro m those of the surrounding terrain, as in the albedo case (usually s maller) and superficial roughness (which decreases above the water masses), with notable consequences to generation of local circulat ions.…”

Section: Effect Of Modification Of Surface Roughnessmentioning

confidence: 99%

“…The smallest surface roughness caused by the existence of a water layer, in the flooded season, possibly inhibited the presence of energy peaks for T variance in s maller length scales [41]. That is, results seen to reflect the horizontal heterogeneity in mechanical and thermal roughness elements, in addition to present contributions, both mechanical forcing and buoyancy, to generate turbulent kinetic energy and temperature variance [39,40,43,44].…”

Section: Effect Of Modification Of Surface Roughnessmentioning

confidence: 99%

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Low Level Jets in the Pantanal Wetland Nocturnal Boundary Layer – Case Studies

Martins¹,

Sá²,

Moraes³

2013

AJEE

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Situated in South America midwest region, Pantanal is a unique biome, alternating dry and flooded periods. An important seasonal variability characteristic fro m Pantanal's energy balance is the occurrence of situations in which sensible heat flu x is positive (bottom-up) during night-time, when the region is flooded enough. In this study it is investigated an interesting aspect of Nocturnal Boundary Layer's (NBL) structure seasonal variability above Pantanal, that is, how Low-Level Jets (LLJ) occurrence and associated turbulent structure. For th is, scale action of different Low-Leve l Jets (LLJ) types on Pantanal's Nocturnal Boundary Layer was investigated through case studies. Six events, distributed the following way, were used: Two events without LLJ's, two events LLJ's weak shear and two events LLJ's strong shear. Fro m the two events without LLJ's, one of them is observed during the dry season and the other, during the flooded one. The same procedure was applied to other events (LLJ's weak shear and LLJ's strong shear). Vertical wind velocity and temperature variance, as well as the covariance among these variables were analyzed and investigated in scale via Wavelet Transform. Remarkab le differences were observed among turbulence in NBL characteristics during the "dry" and "flooded" periods. It was observed that LLJ weak shear acts like a forcing that generates action of top-down mechanisms in the Pantanal's Nocturnal Boundary-layer. On the other hand, LLJ strong shear causes eddies blocking situations with length scales greater than the LLJ height. The decrease of the surface roughness at the flooded season, compared to the dry season, reduces remarkably the temperature variance in the lowest length scales below 350m. Such results are useful for a better understanding of seasonal variability in the Pantanal's Nocturnal Boundary-layer, as well as to other regions with similar environmental characteristics and must be taken into consideration in nu merical simu lations of the flow structure above the region.

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Section: Intensification and Spectral Peak Shift Induced Bymentioning

confidence: 98%

Section: Effect Of Modification Of Surface Roughnessmentioning

confidence: 99%

Section: Effect Of Modification Of Surface Roughnessmentioning

confidence: 99%

Section: Effect Of Modification Of Surface Roughnessmentioning

confidence: 99%

See 2 more Smart Citations

Low Level Jets in the Pantanal Wetland Nocturnal Boundary Layer – Case Studies

Martins¹,

Sá²,

Moraes³

2013

AJEE

View full text Add to dashboard Cite

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“…Field measurements from mangrove forests in Thailand were slightly higher (200-425 W m −2 ; Monji et al, 2002). When compared to other forest types, mangroves are on par with satellite-based E estimates from coniferous forests (100-180 W m −2 ; Venalainen et al, 1999) and within the wide range of temperature deciduous forests (40-400 W m −2 ; Baldocchi and Wilson, 2001) (Table 3) …”

Section: Forest Latent Heat Comparisonsmentioning

confidence: 95%

Spatial and temporal variability in spectral-based surface energy evapotranspiration measured from Landsat 5TM across two mangrove ecotones

Lagomasino

Price

Whitman

et al. 2015

Agricultural and Forest Meteorology

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Observation and simulation of lake‐air heat and water transfer processes in a high‐altitude shallow lake on the Tibetan Plateau

Wang

Chen

et al. 2015

JGR Atmospheres

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Lakes are an important part of the landscape on the Tibetan Plateau. Most of the Plateau lakes' area has been expanding in recent years, but lake‐atmosphere energy and water interaction is poorly understood because of a lack of observational data and adequate modeling systems. Based on the eddy covariance observation over a high‐altitude shallow and small lake (the small Nam Co Lake) during an ice‐free period from 10 April to 30 August 2012, this study analyzes the lake‐air heat and water vapor turbulent transfer processes and evaluates two popular lake‐air exchange models: a bulk aerodynamic transfer model (B model) and a multilayer model (M model). Our main results are as follows: (1) observations show that the bulk transfer coefficient (CE) and roughness length (zoq) for water are higher than those for heat (CH and z0h), especially under low wind speed; (2) both models underestimate turbulent fluxes due to inaccurate values of the Charnock coefficient (α) and the roughness Reynolds number (Rr) which are both important parameters for calculating the roughness length for momentum (z0m) over water; (3) α within a reasonable range of 0.013–0.035 for rough flow and Rr for smooth flow (Rr = 0.11) are 0.031 and 0.54, respectively, by our observation. The wave pattern of shorter wavelength gives a larger z0m in the small and shallow lake; and (4) the B model and the M model gave consistent results, and both models are more suitable for simulation of turbulent flux exchange after z0m optimization.

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Comparison of latent and sensible heat fluxes over boreal lakes with concurrent fluxes over a forest: implications for regional averaging

Cited by 41 publications

References 14 publications

Low Level Jets in the Pantanal Wetland Nocturnal Boundary Layer – Case Studies

Low Level Jets in the Pantanal Wetland Nocturnal Boundary Layer – Case Studies

Spatial and temporal variability in spectral-based surface energy evapotranspiration measured from Landsat 5TM across two mangrove ecotones

Observation and simulation of lake‐air heat and water transfer processes in a high‐altitude shallow lake on the Tibetan Plateau

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