Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau

Wang, Junbo; Huang, Lei; Ju, Jianting; Daut, Gerhard; Ma, Qingfeng; Zhu, Liping; Haberzettl, Torsten; Baade, Jussi; Mäusbacher, Roland; Hamilton, Andrew K.; Graves, KE; Olsthoorn, Jason; Laval, B.

doi:10.1016/j.jhydrol.2020.124668

Cited by 41 publications

(31 citation statements)

References 40 publications

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“…The energy factor is the key that controls ET of the lakes/reservoirs and their surrounding areas (J. B. Wang et al, 2020; W. Wang et al, 2014, 2018); thus, in the long term, increasing air temperature and solar radiation caused by climate change will have important impacts on lakes/reservoirs, which could also lead to an increase in ET of lakes/reservoirs and their surrounding areas (e.g., Lei & Yang, 2017; J. B. Wang et al, 2020; W. Wang et al, 2018).…”

Section: Resultsmentioning

confidence: 99%

Impact of Lake/Reservoir Expansion and Shrinkage on Energy and Water Vapor Fluxes in the Surrounding Area

et al. 2020

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Lakes and reservoirs are important components of freshwater. The expansion and shrinkage of lakes/reservoirs may have impacts on meteorological characteristics and the underlying surface conditions in the surrounding areas, which would further affect energy and water vapor fluxes. In this study, the expansion and shrinkage of the Guanting Reservoir during 2013-2017 were analyzed using remote sensing data. Data collected from the Huailai Remote Sensing Experiment Station were used to analyze the impact of reservoir expansion/shrinkage on energy and water vapor fluxes in the surrounding area. Results showed the annual expansion of the Guanting Reservoir from 2013 to 2017 and a seasonal variation characterized by expansion in spring, shrinkage in summer and autumn, and expansion again in winter was exhibited. Meanwhile, the evapotranspiration (ET) in the surrounding area increased by about 96%, from 446.6 mm in 2013 to 874.7 mm in 2017. In growing season (May to September), the seasonal shrinkage of the reservoir affected ET through net radiation, normalized difference vegetation index (NDVI), and deep soil moisture, while in nongrowing season (January to April and October to December), the seasonal expansion increased ET through the distance between 40-m tower and the reservoir, net radiation, and surface soil moisture. In addition, with the reservoir expanding year by year, the difference in ET between the closer site and further site from the reservoir increased obviously, especially in the nongrowing season during the seasonal expansion of the reservoir. The findings of this study are beneficial for ecosystem restoration and sustainable development of lakes/reservoirs in arid and semiarid areas.

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Section: Resultsmentioning

confidence: 99%

Impact of Lake/Reservoir Expansion and Shrinkage on Energy and Water Vapor Fluxes in the Surrounding Area

et al. 2020

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“…Therefore, climate change will have a greater impact on the aquatic ecology [ 39 – 41 ]. Previous studies have shown that the stratification of lakes in the Qinghai-Tibetan Plateau increased by 6 days every 10 years under the conditions of climate warming [ 68 ]. However, man-made reservoirs formed by dams were similar to lakes and runoff, but their thermal regime and internal mixing mechanisms were different [ 69 ].…”

Section: Resultsmentioning

confidence: 99%

Study of the thermal regime of a reservoir on the Qinghai-Tibetan Plateau, China

et al. 2020

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The Qinghai-Tibetan Plateau region has unique meteorological characteristics, with low air temperature, low air pressure, low humidity, little precipitation, and strong diurnal variation. A two-dimensional hydrodynamic CE-QUAL-W2 model was configured for the Pangduo Reservoir to better understand the thermal structure and diurnal variation inside the reservoir under the local climate and hydrological conditions on the Qinghai-Tibetan Plateau. Observation data were used to verify the model, and the results showed that the average error of the 6 profile measured monthly from August to December 2016 was 0.1°C, and the root-mean-square error (RMSE) was 0.173°C. The water temperature from August 2016 to September 2017 was simulated by inputting measured data as model inputs. The results revealed that the reservoir of the Qinghai-Tibetan Plateau was a typical dimictic reservoir and the water mixed vertically at the end of March and the end of October. During the heating period, thermal stratification occurred, with strong diurnal variation in the epilimnion. The mean variance of the diurnal water temperature was 0.10 within a 5 m water depth but 0.04 in the whole water column. The mixing mode of inflow changed from undercurrent, horizontal-invaded flow and surface layer flow in one day. In winter, the diurnal variation was weak due to the thermal protection of the ice cover, while the mean variance of diurnal water temperature was 0.00 within both 5 m and the whole water column. Compared to reservoirs in areas with low altitude but the same latitude, significant differences occurred between the temperature structure of the low-altitude reservoir and the Pangduo Reservoir (P<0.01). The Pangduo Reservoir presented a shorter stratification period and weaker stratification stability, and the annual average SI value was 26.4 kg/m2, which was only 7.5% that of the low-altitude reservoir. The seasonal changes in the net heat flux received by the surface layers determined the seasonal cycle of stratification and mixing in reservoirs. This study provided a scientific understanding of the thermal changes in stratified reservoirs under the special geographical and meteorological conditions on the Qinghai-Tibetan Plateau. Moreover, this model can serve as a reference for adaptive management of similar dimictic reservoirs in cold and high-altitude areas.

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“…The study area is located on the Tibetan Plateau (Figure 1a), where the Nam Co Lake (lake center at 30 • 340 N, 90 • 30 E, [37]) is the second largest lake (Figure 1b). The selected study area is the Zhagu subcatchment (Figure 1c), inside the eastern Nam Co catchment area.…”

Section: Study Areamentioning

confidence: 99%

Delineation of a Quaternary Aquifer Using Integrated Hydrogeological and Geophysical Estimation of Hydraulic Conductivity on the Tibetan Plateau, China

Tran

Buckel

Maurischat

et al. 2021

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Groundwater is the most unexplored element of the hydrologic cycle on the Tibetan Plateau (TP) due to harsh climate conditions. This study aims at delineating and characterizing the unexplored Zhanongtang–Ganmanong aquifer, situated in the Zhagu subcatchment of the Nam Co catchment, south-central TP. Multiple hydrogeophysical and lithological in situ field and laboratory methods are applied: depth-to-water-table measurements, grain size analysis, hydraulic empirical and field methods to estimate hydraulic conductivity (K), and analysis of electrical resistivity tomography profiles. Integration of these methods revealed the existence of a Quaternary hydrostratigraphic unit that was found to be unconsolidated, laterally heterogeneous and homogeneous over depth. The results revealed consistent K ranges of three K zones, which is in accordance with local lithology. The K ranges are applicable to other locations within the Nam Co catchment with similar lithology as in the study area without further field experiments. Permafrost was found to be absent in the study area ranging from 4730 m a.s.l. to 5200 m a.s.l. altitude. These results provide insight into the hydrogeological conditions of the TP and are useful for conceptual and numerical groundwater flow modeling to predict future changes of water fluxes and water budgets caused by climatic change, especially in remote areas.

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Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau

Cited by 41 publications

References 40 publications

Impact of Lake/Reservoir Expansion and Shrinkage on Energy and Water Vapor Fluxes in the Surrounding Area

Impact of Lake/Reservoir Expansion and Shrinkage on Energy and Water Vapor Fluxes in the Surrounding Area

Study of the thermal regime of a reservoir on the Qinghai-Tibetan Plateau, China

Delineation of a Quaternary Aquifer Using Integrated Hydrogeological and Geophysical Estimation of Hydraulic Conductivity on the Tibetan Plateau, China

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