Evaporation from a pine forest - using the aerodynamic method and bowen ratio method

Vogt, Roland; Jaeger, L.

doi:10.1016/0168-1923(90)90137-u

Cited by 22 publications

(13 citation statements)

References 12 publications

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“…Schott (1980) found z o to increase and d to become smaller with growing wind speed values using 1975 data. Vogt and Jaeger (1990) confirm these results. Fig.…”

Section: The Parameters Of the Wind Profilesupporting

confidence: 81%

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Twenty years of heat and water balance climatology at the Hartheim pine forest, Germany

Jaeger

Kessler

1997

Agricultural and Forest Meteorology

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The Hartheim pine forest is an ecosystem in the dry region of the southern upper Rhine valley in Germany. A project "Monitoring the Hartheim pine forest" was initiated in 1973 and is continuing. One of its objectives is to provide long-term measurements of the net radiation and its components, to calculate the energy fluxes and other hydrological parameters.Sufficient studies on the climatology of the 'primitive' elements of climate exist in central Europe. But long-term series of measurements of the physical processes controlling these elements above different characteristic surface types are missing. The study of heat balance monographies (e.g. Budyko, 1974;Miller, 1981;Kessler, 1985;Hantel, 1989;Baumgartner, 1990) illustrates this deficit drastically. An aspect of our investigations is to study the long-term behaviour of the above-mentioned complex physical variables in relation to weather and climate. Furthermore, we examine whether it is possible to distinguish between the changes, for example, of the ratio of net radiation to global radiation caused by the dynamics of climate and the changes caused by alterations of the ecosystem. Natural and human influences on the pine stand at Hartheim led to an 8-m growth in height during the monitoring period.We present some examples showing that the dynamics of the weather hide other effects within the frame of 20 years of measurements. On the other hand, evident changes in interception and transpiration are due to a changing forest ecosystem.

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“…Schott (1980) found z o to increase and d to become smaller with growing wind speed values using 1975 data. Vogt and Jaeger (1990) confirm these results. Fig.…”

Section: The Parameters Of the Wind Profilesupporting

confidence: 81%

“…The problems of the wind profile measurements at Hartheim forest are described by Vogt and Jaeger (1990). The question is answered by means of a data set beginning in 1985 (Fig.…”

Section: The Parameters Of the Wind Profilementioning

confidence: 99%

Twenty years of heat and water balance climatology at the Hartheim pine forest, Germany

Jaeger

Kessler

1997

Agricultural and Forest Meteorology

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“…Relation (14) and (15) indicate that with the increase of drag coefficient, z 0 increases. And the increase of u * means the increase of friction, which indicates that the resistance increases and leads to the increase of z 0 .…”

Section: Discussionmentioning

confidence: 94%

“…The higher the wind speed is, the more strenuous the turbulence is, and the lower z 0 is [13] . Vogt et al [14] found that the relationship of z 0 , d with wind speed is influenced by wind speed of the lowest level above vegetation, and the heights of wind profile. The relationship would change by changing the heights of wind profile, and the relationship needs further study.…”

Section: Discussionmentioning

confidence: 99%

“…Specifically, in Qianyanzhou and Changbai Mountains Experimental Station, with the increase of wind speed, z 0 decreases, and in Yucheng Experimental Station, z 0 does not change with wind speed. The phenomenon can be explained by the following relation (13) and (14), which are relations for aerodynamic roughness length in neutral atmospheric stability based on Monin-Obukhov similarity theory:…”

Section: Discussionmentioning

confidence: 99%

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Surface roughness length dynamic over several different surfaces and its effects on modeling fluxes

et al. 2006

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Roughness length and zero-plane displacement over three typical surfaces were calculated iteratively by least-square method, which are Yucheng Experimental Station for agriculture surfaces, Qianyanzhou Experimental Station for complex and undulant surfaces, and Changbai Mountains Experimental Station for forest surfaces. On the basis of roughness length dynamic, the effects of roughness length dynamic on fluxes were analyzed with SEBS model. The results indicate that, aerodynamic roughness length changes with vegetation conditions (such as vegetation height, LAI), wind speed, friction velocity and some other factors. In Yucheng and Changbai Mountains Experimental Station, aerodynamic roughness length over the fetch of flux tower changes with vegetation height and LAI obviously, that is, with the increase of LAI, roughness length increases to the peak value firstly, and then decreases.

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Seasonal modelling of catchment water balance: A two-levle cascading modification of TOPMODEL to increase the realism of spatio-temporal processes

Ostendorf

Manderscheid

1997

Hydrol. Process.

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A general problem of hydrological modelling is parameter identi®cation for the driving processes. To examine the longterm dynamics of the water balance of a small (4 . 2 km 2 ) forested catchment in south-east Germany (Lehstenbach), TOPMODEL has been adapted as a two-level cascading approach. Only the lower cascade is allowed to respond dynamically. This modi®ed TOPMODEL version accounts for the observations that surface runo only takes place in a small portion of the catchment and that water¯ow in large portions of the catchment occurs through groundwater aquifers with a lateral recharge to the downslope regions. Water from an upper catchment region is transferred to a lower storage. The border between the two areas is represented as a topographic index (ATB) threshold that can be varied in the model. The best ®ts are obtained if only 60% of the catchment area is allowed to react dynamically. A substantial improvement of the runo description has been achieved by a moderate increase of model complexity. Results of a Monte Carlo simulation showed that the model structure has a¯at global optimal solution.In order to quantify the boundary conditions, we combined direct estimates of tree and understorey transpiration, maps of tree age and understorey cover to estimate empirically the total catchment evapotranspiration. The context of a dynamic hydrological model allows an evaluation of ecological data in the context of catchment scale dynamics. Vapour pressure de®cit can be assumed to be the major driver of vegetation±atmosphere water transfer. Soil moisture does not aect tree transpiration in this catchment. The results show that transpiration measurements can be scaled to the catchment scale in spite of variations between sites of up to 100%.

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Evaporation from a pine forest - using the aerodynamic method and bowen ratio method

Cited by 22 publications

References 12 publications

Twenty years of heat and water balance climatology at the Hartheim pine forest, Germany

Twenty years of heat and water balance climatology at the Hartheim pine forest, Germany

Surface roughness length dynamic over several different surfaces and its effects on modeling fluxes

Seasonal modelling of catchment water balance: A two-levle cascading modification of TOPMODEL to increase the realism of spatio-temporal processes

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