Physical changes within a large tropical hydroelectric reservoir induced by wintertime cold front activity

Curtarelli, Marcelo; Alcântara, Enner; Rennó, Camilo Daleles; Stech, José

doi:10.5194/hess-18-3079-2014

Cited by 20 publications

(16 citation statements)

References 51 publications

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“…Compared to surrounding land surfaces, lakes tend to reduce diurnal temperature range [ Samuelsson et al ., ]. Lakes in low latitude which are characterized by high surface temperature increase latent heat flux [ Curtarelli et al ., ]. What is more, the lake‐land contrast at diurnal scale leads to lake‐land breeze circulation, which changes local wind field and even mesoscale flow [ Samuelsson and Tjernstrom , ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the WRF‐lake model over a highland freshwater lake in southwest China

Liu

et al. 2016

JGR Atmospheres

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Evaluation of the Weather Research and Forecasting Model version 3.7.1 lake model performance on lake physical processes and lake‐atmosphere interaction at Erhai Lake was conducted with in situ observation data sets over the lake to verify the model results. The lake model with default parameters presented significant negative bias during the day and positive bias during the night on lake surface temperature. Calibrations of water absorption and extinction coefficients, surface roughness length, and eddy diffusion coefficient were carried out to correct this bias. The added absorption and extinction coefficients increased solar radiation in upper water layer, leading to a little higher surface temperature. Compared to constant surface roughness lengths, parameterization of roughness lengths as functions of friction velocity and fetch length significantly improved simulations of lake surface temperature and sensible heat flux. In Erhai Lake, eddy diffusion coefficient of the Henderson‐Sellers parameterization is smaller than that in deep lakes. The eddy diffusion coefficient was reduced by a factor of 0.05 in dry season and 0.02 in wet season, respectively, to restrict mixing strength, generating a reasonable diurnal range with observed surface temperature. The adjusted parameter simulations matched better with in situ observations in diurnal cycle of temperature and surface heat fluxes but still overestimated wind speed. Topographic correction is effective to correct the bias, indicating that topographic correction over complex terrain was necessary.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the WRF‐lake model over a highland freshwater lake in southwest China

Liu

et al. 2016

JGR Atmospheres

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“…6); it appears this circulation pattern is due to the development of a topographic gyre. When wind stress acts along a long and narrow basin of varying depth, a double gyre pattern develops with coastal currents in the direction of the wind stress and a return flow in the center of the basin in the opposite direction (Csanady 1982). In contrast, a flow pattern characteristic of a topographic gyre was not observed in Ulysses Bay.…”

Section: Exchange Between the Embayments And The Lake Interiormentioning

confidence: 96%

“…One of the challenges in exploring the range of flows that occur within a lake at the right spatial and temporal scales to adequately understand the exchange between the littoral zone and interior is the lack of high‐resolution sampling data (Rueda et al ), and therefore hydrodynamic models are able to fill the gaps in the observational data (Rueda and Schladow ; Marti and Imberger ; Curtarelli et al ). Two‐dimensional numerical analyses of buoyancy‐driven flows have incorporated unsteady forcing and interacting forces such as wind (Farrow ), as well as vegetation shading and drag (Lin ).…”

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confidence: 99%

Wind and buoyancy driven horizontal exchange in shallow embayments of a tropical reservoir: Lake Argyle, Western Australia

Woodward

Marti

Imberger

et al. 2017

Limnology & Oceanography

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Many factors including depth, vegetation density, wind, and gyres may act to influence the littoral exchange in a water body but very few studies have investigated the interaction between more than two of these factors at any time. To investigate these controls on horizontal exchange in a large tropical reservoir, we conducted a 9‐d intensive field experiment in Lake Argyle, Western Australia. The experiment began with a 7‐d cooling period that generated water in the shallows of the reservoir embayments that was persistently cooler than the interior. This led to an underflow of dense water that moved from the lake boundary toward the center of the reservoir. A three‐dimensional hydrodynamic model (ELCOM) was able to adequately reproduce this thermal structure and was used to demonstrate its sensitivity to wind‐sheltering effects and submerged macrophyte presence. Further analysis of the predictions indicated that when the ratio of the shear and buoyancy force, averaged over 6 h (B6h) and 6‐h averaged wind speed in the direction of the embayment (U6h) was (1) greater than 0.5 ms−1 and 4.5 ms−1 respectively, the exchange was dominated by a topographic gyre formation, (2) when 0.1 < B6h < 0.5 and 2.4 ms−1 < U6h < 4.5 ms−1, the resulting circulation was a combination of differential cooling flows and a topographic gyre circulation, and (3) when U6h fell below 2.4 ms−1, purely buoyancy driven flow occurred but only if the buoyancy forces across the embayments were an order of magnitude greater than wind‐induced velocity shear.

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“…The cold fronts and the meteorological properties of the air masses behind cold fronts (e.g., windy, cold and dry) 25 significantly promoted turbulent exchange of sensible heat (Hs) and latent heat (LE) through enhanced turbulent mixing thermally and mechanically, whereas southerly winds with warm and humid air masses generally suppressed turbulent exchanges of Hs and LE over a mid-latitude large reservoir in Mississippi (Liu et al, 2009;Liu et al, 2012). In response to the changes in the weather conditions, the heat balance over a large tropical reservoir in Brazil is substantially altered, and the heat loss can be 30 twice or threefold greater during cold front days than that during the non-cold-front days (Curtarelli et al, 2014). Consistent diurnal peaks in latent heat flux during the afternoon were observed as a result of strong dry winds coinciding with peak water surface temperatures over a small subtropical reservoir in Australia (McGloin et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

The monsoon effect on energy and carbon exchange processes over a highland lake in southwest of China

Du¹,

Liu²,

Xu³

et al. 2018

Preprint

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Abstract. Lake Erhai is a subtropical highland shallow lake on southeast margin of Tibetan Plateau, 10 which is influenced by both South Asian and East Asian summer monsoon. Based on four years continuous eddy covariance (EC) data over Lake Erhai, the monsoon effect on water-atmosphere exchange process is investigated by comparing the energy and CO 2 fluxes patterns and their main drivers during pre-monsoon (March-April), monsoon (May-October) and post-monsoon (November-December) periods. The results show the atmospheric properties display a large difference 15 for during three different periods. There is a negative difference between water surface and air temperature (△T) during pre-monsoon period, while a positive △T during post-monsoon period. The diurnal sensible heat flux (Hs) is larger during post-monsoon period, while the latent heat flux (LE) is larger during monsoon period. The monthly average Hs and heat storage (△Q) in the lake remain negative during pre-monsoon period and the early monsoon period, and they become positive in the 20 middle monsoon period, which indicates that the lake absorbs heat at first and releases it subsequently. LE plays a dominating role in the energy partitioning of the lake. The Bowen ratio is higher during post-monsoon period. An uptake of CO 2 flux is observed in middle of a day during monsoon and post-monsoon period. The ΔT is the main drivers for Hs and the effect of ΔT is increased as time scales are extended from half-hourly to monthly. The wind speed has a weak effect on Hs but a strong effect 25 on LE and CO 2 fluxes. Similar main drivers for Hs are found during pre-monsoon period and post-monsoon period, which is also found for CO 2 flux, indicating a large impact of monsoon on the heat and carbon exchange process over Lake Erhai.

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Physical changes within a large tropical hydroelectric reservoir induced by wintertime cold front activity

Cited by 20 publications

References 51 publications

Evaluation of the WRF‐lake model over a highland freshwater lake in southwest China

Evaluation of the WRF‐lake model over a highland freshwater lake in southwest China

Wind and buoyancy driven horizontal exchange in shallow embayments of a tropical reservoir: Lake Argyle, Western Australia

The monsoon effect on energy and carbon exchange processes over a highland lake in southwest of China

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