scholarly journals Thermal regime, energy budget and lake evaporation at Paiku Co, a deep alpine lake in the central Himalayas

2019 ◽  
Author(s):  
Yanbin Lei ◽  
Tandong Yao ◽  
Kun Yang ◽  
Zhu La ◽  
Yaoming Ma ◽  
...  
Keyword(s):  
Energy Budget ◽  
Lake Water ◽  
Water Budget ◽  
Lake Level ◽  
Thermal Structure ◽  
Seasonal Pattern ◽  
Alpine Lake ◽  
Net Radiation ◽  
Central Himalayas ◽  
Lake Evaporation

Abstract. Evaporation from hydrologically-closed lakes is one of the largest components of their lake water budget, however, its effects on seasonal lake level changes is less investigated due to lack of comprehensive observation of lake water budget. In this study, lake evaporation were determined through energy budget method at Paiku Co, a deep alpine lake in the central Himalayas, based on three years' in-situ observations of thermal structure and hydrometeorology (2015–2018). Results show that Paiku Co was thermally stratified between July and October and fully mixed between November and June. Between April and July when the lake gradually warmed, about 66.5 % of the net radiation was consumed to heat the lake water. Between October and January when the lake cooled, heat released from lake water was about 3 times larger than the net radiation. Changes in lake heat storage largely determined the seasonal pattern of lake evaporation. There was about a 5 month lag between the maximum lake evaporation and maximum net radiation due to the large heat capacity of lake water. Lake evaporation was estimated to be 975 ± 39 mm between May and December during the study period, with low values in spring and early summer, and high values in autumn and early winter. The seasonal pattern of lake evaporation at Paiku Co significantly affects lake level seasonality, that is, significant lake level decrease in post-monsoon season while slight in pre-monsoon. This study may have implications for the different amplitudes of seasonal lake level variations between deep and shallow lakes.

scholarly journals Thermal regime, energy budget and lake evaporation at Paiku Co, a deep alpine lake in the central Himalayas

2020 ◽  
Author(s):  
Yanbin Lei ◽  
Tandong Yao ◽  
Kun Yang ◽  
Yaoming Ma ◽  
Broxton W. Bird ◽  
...  
Keyword(s):  
Lake Water ◽  
Lake Level ◽  
Thermal Structure ◽  
Monsoon Season ◽  
Seasonal Pattern ◽  
Alpine Lake ◽  
The Tibetan Plateau ◽  
Net Radiation ◽  
Central Himalayas ◽  
Lake Evaporation

Abstract. Endorheic lakes on the Tibetan Plateau (TP) experienced dramatic changes in area and volume during the past decades. However, the hydrological processes associated with lake dynamics are still less understood. In this study, lake evaporation and its impact on seasonal lake level changes at Paiku Co, central Himalayas, were investigated based on three years of in-situ observations of lake thermal structure and hydrometeorology (2015–2018). The results show that Paiku Co is a dimictic lake with thermal stratification at the water depth of 15–30 m between July and October. As a deep alpine lake, the large heat storage significantly influenced the seasonal pattern of heat flux over lake surface. Between April and July, when the lake gradually warmed, about 66.5% of the net radiation was consumed to heat lake water. Between October and January, when the lake cooled, heat released from lake water was about 3 times larger than the net radiation. There was ~5 month lag between the maximum lake evaporation and maximum net radiation at Paiku Co. Lake evaporation was estimated to be 975±82 mm between May and December, with low values in spring and early summer, and high values in autumn and early winter. The seasonal pattern of lake evaporation at Paiku Co significantly affected lake level seasonality, that is, a significant lake level decrease of 3.8 mm/day during the post-monsoon season while a slight decrease of 1.3 mm/day during the pre-monsoon season. This study may have implications for the different amplitudes of seasonal lake level variations between deep and shallow lakes.

scholarly journals Contrasting hydrological and thermal intensities determine seasonal lake-level variations – a case study at Paiku Co on the southern Tibetan Plateau

2021 ◽  
Vol 25 (6) ◽  
pp. 3163-3177
Author(s):  
Yanbin Lei ◽  
Tandong Yao ◽  
Kun Yang ◽  
Yaoming Ma ◽  
Broxton W. Bird ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Lake Level ◽  
Thermal Structure ◽  
Monsoon Season ◽  
Seasonal Pattern ◽  
The Tibetan Plateau ◽  
Post Monsoon ◽  
Level Increase ◽  
Post Monsoon Season ◽  
Lake Evaporation

Abstract. Evaporation from hydrologically closed lakes is one of the largest components of the lake water budget; however, its effects on seasonal lake-level variations remain unclear on the Tibetan Plateau (TP) due to a lack of comprehensive observations. In this study, weekly lake evaporation and its effects on seasonal lake-level variations are investigated at Paiku Co on the southern TP using in situ observations of thermal structure and hydrometeorology (2015–2018). Lake evaporation from Paiku Co was estimated to be 975±142 mm during the ice-free period (May to December), characterized by low values of 1.7 ± 0.6 mm d−1 during the pre-monsoon season (May to June), high values of 5.5±0.6 mm d−1 during the post-monsoon season (October to December), and intermediate values of 4.0±0.6 mm d−1 during the monsoon season (July to September). There was a ∼ 5-month lag between the maximum net radiation (June) and maximum lake evaporation (November). These results indicate that the seasonal pattern of lake evaporation from Paiku Co was significantly affected by the large lake heat storage. Contrasting hydrological and thermal intensities may play an important role in the large amplitude of seasonal lake-level variations at deep lakes like Paiku Co. High inflow from monsoon precipitation and glacier melting and moderate lake evaporation, for instance, drove rapid lake-level increase during the monsoon season. In contrast, high lake evaporation and reduced inflow caused lake level to decrease significantly during the post-monsoon season. This study implies that lake evaporation may play an important role in the different amplitudes of seasonal lake-level variations on the TP.

scholarly journals Dead Sea evaporation by eddy covariance measurements vs. aerodynamic, energy budget, Priestley–Taylor, and Penman estimates

2018 ◽  
Vol 22 (2) ◽  
pp. 1135-1155 ◽  
Author(s):  
Jutta Metzger ◽  
Manuela Nied ◽  
Ulrich Corsmeier ◽  
Jörg Kleffmann ◽  
Christoph Kottmeier
Keyword(s):  
Energy Budget ◽  
Water Budget ◽  
Heat Storage ◽  
Sea Water ◽  
Correlation Coefficients ◽  
Dead Sea ◽  
Eddy Covariance Measurements ◽  
Lake Evaporation ◽  
The Dead ◽  
Storage Term

Abstract. The Dead Sea is a terminal lake, located in an arid environment. Evaporation is the key component of the Dead Sea water budget and accounts for the main loss of water. So far, lake evaporation has been determined by indirect methods only and not measured directly. Consequently, the governing factors of evaporation are unknown. For the first time, long-term eddy covariance measurements were performed at the western Dead Sea shore for a period of 1 year by implementing a new concept for onshore lake evaporation measurements. To account for lake evaporation during offshore wind conditions, a robust and reliable multiple regression model was developed using the identified governing factors wind velocity and water vapour pressure deficit. An overall regression coefficient of 0.8 is achieved. The measurements show that the diurnal evaporation cycle is governed by three local wind systems: a lake breeze during daytime, strong downslope winds in the evening, and strong northerly along-valley flows during the night. After sunset, the strong winds cause half-hourly evaporation rates which are up to 100 % higher than during daytime. The median daily evaporation is 4.3 mm d−1 in July and 1.1 mm d−1 in December. The annual evaporation of the water surface at the measurement location was 994±88 mm a−1 from March 2014 until March 2015. Furthermore, the performance of indirect evaporation approaches was tested and compared to the measurements. The aerodynamic approach is applicable for sub-daily and multi-day calculations and attains correlation coefficients between 0.85 and 0.99. For the application of the Bowen ratio energy budget method and the Priestley–Taylor method, measurements of the heat storage term are inevitable on timescales up to 1 month. Otherwise strong seasonal biases occur. The Penman equation was adapted to calculate realistic evaporation, by using an empirically gained linear function for the heat storage term, achieving correlation coefficients between 0.92 and 0.97. In summary, this study introduces a new approach to measure lake evaporation with a station located at the shoreline, which is also transferable to other lakes. It provides the first directly measured Dead Sea evaporation rates as well as applicable methods for evaporation calculation. The first one enables us to further close the Dead Sea water budget, and the latter one enables us to facilitate water management in the region.

UNCERTAINTIES IN THE ESTIMATION OF A SHALLOW LAKE WATER BUDGET

2008 ◽  
Author(s):  
TAMÁS WEIDINGER ◽  
ÁRPÁD BORDÁS ◽  
SZILVIA SIMON ◽  
JUDIT MÁDLNÉ SZOŐNYI
Keyword(s):  
Lake Water ◽  
Shallow Lake ◽  
Water Budget

scholarly journals Assessment of the Effects of Climate Change on Evapotranspiration with an Improved Elasticity Method in a Nonhumid Area

2018 ◽  
Vol 10 (12) ◽  
pp. 4589 ◽  
Author(s):  
Lei Tian ◽  
Jiming Jin ◽  
Pute Wu ◽  
Guo-yue Niu
Keyword(s):  
Climate Change ◽  
Wind Speed ◽  
Energy Budget ◽  
Yellow River ◽  
Rate Of Change ◽  
Climatic Variables ◽  
Accurate Estimation ◽  
Net Radiation ◽  
River Watershed ◽  
Significant Downward Trend

Climatic elasticity is a crucial metric to assess the hydrological influence of climate change. Based on the Budyko equation, this study performed an analytical derivation of the climatic elasticity of evapotranspiration (ET). With this derived elasticity, it is possible to quantitatively separate the impacts of precipitation, air temperature, net radiation, relative humidity, and wind speed on ET in a watershed. This method was applied in the Wuding River Watershed (WRW), located in the center of the Yellow River Watershed of China. The estimated rate of change in ET caused by climatic variables is −10.69 mm/decade, which is close to the rate of change in ET (−8.06 mm/decade) derived from observable data. The accurate estimation with the elasticity method demonstrates its reliability. Our analysis shows that ET in the WRW had a significant downward trend, but the ET ratio in the WRW has increased continually over the past 52 years. Decreasing precipitation is the first-order cause for the reduction of ET, and decreasing net radiation is the secondary cause. Weakening wind speed also contributed to this reduction. In contrast, regional warming led to an increase in ET that partly offset the negative contributions from other climatic variables. Moreover, reforestation can affect the energy budget of a watershed by decreasing albedo, compensating for the negative influence of global dimming. The integrated effect from precipitation and temperature can affect the energy budget of a watershed by causing a large fluctuation in winter albedo.

scholarly journals On the surface energy budget of sea ice

1997 ◽  
Vol 43 (143) ◽  
pp. 122-130 ◽  
Author(s):  
Gerd Wendler ◽  
Ute Adolphs ◽  
Adrian Hauser ◽  
Blake Moore
Keyword(s):  
Surface Energy ◽  
Sea Ice ◽  
Energy Budget ◽  
High Surface ◽  
Open Water ◽  
Ice Cover ◽  
Surface Energy Budget ◽  
Net Radiation ◽  
Pack Ice ◽  
Ice Concentration

AbstractThe surface energy budget was investigated during a cruise through the pack ice in the Southern Ocean. The time of observation was close to mid-summer. Some of the more important findings were: The mean albedo varied from 11 % for open water to 59% for 10/10 ice cover. Hourly values span the range from 6% (open water) to 76% (total ice cover).The net heat flux into the ocean (B) was on average 109 W m−2, If this energy were used solely for melting of sea ice, 30 mm could be melted each day.For low surface albedos (ice concentration below 7/10), the net radiation increased with decreasing cloudiness. However, the opposite was the case for a high surface albedo. The last point shows the importance of clouds on the surface energy budget. Not only should their presence or absence be known but also the reflectivity of the underlying surface, as it might change the net radiation in opposite ways.

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