Heat storage and energy balance fluxes for a temperate deciduous forest

Oliphant, A. J.; Grimmond, Sue; Zutter, H.N.; Schmid, Hans‐Peter; Su, Hong-Bing; Scott, Steve; Offerle, Brian; Randolph, J. C.; Ehman, Jeffrey L.

doi:10.1016/j.agrformet.2004.07.003

Cited by 200 publications

(177 citation statements)

References 33 publications

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“…2). Similar mean diurnal patterns are reported in Vogt et al (1996) and Oliphant et al (2004). Calculations using only the humidity measurement just above the canopy (z=30 m and z=24 m, respectively) decreased the maximum in the morning and increased the maximum in the evening for all sites slightly.…”

Section: Latent Heat Storage Change J Esupporting

confidence: 58%

“…Air density ρ a and specific heat capacity of air c p is assumed to be constant over the whole canopy layer, following former studies (e.g. McCaughey 1985; Oliphant et al 2004). …”

Section: Sensible Heat Storage Change J Hmentioning

confidence: 99%

“…McCaughey 1985;McCaughey and Saxton 1988;Moore and Fisch 1986;Vogt et al 1996) and only few studies use more than one measurement level (e.g. Oliphant et al 2004). For reasons of consistency, J E was calculated in the same way as J H on half-hourly basis, i.e.…”

Section: Latent Heat Storage Change J Ementioning

confidence: 99%

“…For c veg , a value of 2,958 J kg −1 K −1 was chosen which was used in several studies (e.g. McCaughey 1985;McCaughey and Saxton 1988;Oliphant et al 2004) following Thom (1975) that c veg is approximately 70% of the corresponding value for water.…”

Section: Biomass Heat Storage Change J Vegmentioning

confidence: 99%

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Available energy and energy balance closure at four coniferous forest sites across Europe

Moderow

Aubinet

Feigenwinter

et al. 2009

Theor Appl Climatol

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The available energy (AE), driving the turbulent fluxes of sensible heat and latent heat at the earth surface, was estimated at four partly complex coniferous forest sites across Europe (Tharandt, Germany; Ritten/Renon, Italy; Wetzstein, Germany; Norunda, Sweden). Existing data of net radiation were used as well as storage change rates calculated from temperature and humidity measurements to finally calculate the AE of all forest sites with uncertainty bounds. Data of the advection experiments MORE II (Tharandt) and ADVEX (Renon, Wetzstein, Norunda) served as the main basis. On-site data for referencing and cross-checking of the available energy were limited. Applied cross checks for net radiation (modelling, referencing to nearby stations and ratio of net radiation to global radiation) did not reveal relevant uncertainties. Heat storage of sensible heat J H , latent heat J E , heat storage of biomass J veg and heat storage due to photosynthesis J C were of minor importance during day but of some importance during night, where J veg turned out to be the most important one. Comparisons of calculated storage terms (J E , J H ) at different towers of one site showed good agreement indicating that storage change calculated at a single point is representative for the whole canopy at sites with moderate heterogeneity. The uncertainty in AE was assessed on the basis of literature values and the results of the applied cross checks for net radiation. The absolute mean uncertainty of AE was estimated to be between 41 and 52 W m −2 (10-11 W m −2 for the sum of the storage terms J and soil heat flux G) during mid-day (approximately 12% of AE). At night, the absolute mean uncertainty of AE varied from 20 to about 30 W m −2 (approximately 6 W m −2 for J plus G) resulting in large relative uncertainties as AE itself is small. An inspection of the energy balance showed an improvement of closure when storage terms were included and that the imbalance cannot be attributed to the uncertainties in AE alone.

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Section: Latent Heat Storage Change J Esupporting

confidence: 58%

“…Air density ρ a and specific heat capacity of air c p is assumed to be constant over the whole canopy layer, following former studies (e.g. McCaughey 1985; Oliphant et al 2004). …”

Section: Sensible Heat Storage Change J Hmentioning

confidence: 99%

Section: Latent Heat Storage Change J Ementioning

confidence: 99%

Section: Biomass Heat Storage Change J Vegmentioning

confidence: 99%

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Available energy and energy balance closure at four coniferous forest sites across Europe

Moderow

Aubinet

Feigenwinter

et al. 2009

Theor Appl Climatol

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“…Over vegetated surfaces, the intercept of the regression is not attributed to a physical cause (Wilson et al, 2002;Oliphant et al, 2004). Here, as noted, if we assume that the anthropogenic fluxes represent a relatively constant addition to the available energy, then the intercept can be interpreted as Q F + ε.…”

Section: Energy Balance Closurementioning

confidence: 98%

Heat storage and anthropogenic heat flux in relation to the energy balance of a central European city centre

Offerle

Grimmond

Fortuniak

2005

Intl Journal of Climatology

Self Cite

191

151

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The role of net heat storage Q S and anthropogenic heat Q F are considered in the surface energy balance for a downtown area in Łódź, Poland, for a 2 year period. Eddy covariance measurements provide estimates of the turbulent heat fluxes and radiometric measurements of the net all-wave radiation. A method to determine Q S based on representative surface temperature sampling is employed and compared with results from two other models. Results show that Q S is an important flux on the scale of hours to days and that it can be more than 10 W m −2 , on average, for periods of a week or more. By incorporating Q S estimates over hourly intervals, Q F was then determined as the residual of the energy balance. Using the approach, Q F averaged 32 W m −2 from October to March (60% of available energy), and −3 W m −2 from June to August. The physically unrealistic negative values for the summer period may suggest underestimation of turbulent fluxes, but no causal factor was identified. Although energy balance closure was close to 100% throughout the year, there was weaker agreement in the winter. This is attributed to errors in estimates of Q S and variation in Q F . Results highlight the need for future investigations of the urban surface energy balance to incorporate more complete measurements and estimates of Q S .

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Evaluating the complementary relationship of evapotranspiration in the alpine steppe of the Tibetan Plateau

Zhang

Szilágyi

et al. 2015

Water Resources Research

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The complementary relationship (CR) of evapotranspiration allows the estimation of the actual evapotranspiration rate (ET a ) of the land surface using only routine meteorological data, which is of great importance in the Tibetan Plateau (TP) due to its sparse observation network. With the highest in situ automatic climate observation system in a typical semiarid alpine steppe region of the TP, the wind function of Penman was replaced by one based on the Monin-Obukhov Similarity theory for calculating the potential evapotranspiration rate (ET p ); the Priestley-Taylor coefficient, a, was estimated using observations in wet days; and the slope of the saturation vapor pressure curve was evaluated at an estimate of the wet surface temperature, provided the latter was smaller than the actual air temperature. A symmetric CR was obtained between the observed daily actual and potential evapotranspiration. Local calibration of the parameter value (in this order) is key to obtaining a symmetric CR: a, wet environment air temperature (T wea ), and wind function. Also, present symmetric CR contradicts previous research that used default parameter values for claiming an asymmetric CR in arid and semiarid regions of the TP. The effectiveness of estimating the daily ET a via symmetric CR was greatly improved when local calibrations were implemented. At the same time, an asymmetric CR was found between the observed daily ET a and pan evaporation rates (E pan ), both for D20 aboveground and E601B sunken pans. The daily ET a could also be estimated by coupling the E pan of D20 aboveground and/or E601B sunken pan through CR. The former provided good descriptors for observed ET a , while the latter still tended to overestimate it to some extent.

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Heat storage and energy balance fluxes for a temperate deciduous forest

Cited by 200 publications

References 33 publications

Available energy and energy balance closure at four coniferous forest sites across Europe

Available energy and energy balance closure at four coniferous forest sites across Europe

Heat storage and anthropogenic heat flux in relation to the energy balance of a central European city centre

Evaluating the complementary relationship of evapotranspiration in the alpine steppe of the Tibetan Plateau

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