scholarly journals Comments to “Thermal regime, energy budget and lake evaporation at Paiku Co, a deep alpine lake in the central Himalayas”　by Lei et al.

2020 ◽  
Author(s):  
Anonymous
Keyword(s):  
Energy Budget ◽  
Thermal Regime ◽  
Alpine Lake ◽  
Central Himalayas ◽  
Lake Evaporation

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 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.

Estimating daily lake evaporation from biweekly energy-budget data

2017 ◽  
Vol 31 (25) ◽  
pp. 4530-4539 ◽  
Author(s):  
Mie Andreasen ◽  
Donald O. Rosenberry ◽  
David I. Stannard
Keyword(s):  
Energy Budget ◽  
Lake Evaporation

scholarly journals The Summer Surface Energy Budget of the Ice-Free Area of Northern James Ross Island and Its Impact on the Ground Thermal Regime

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 877
Author(s):  
Klára Ambrožová ◽  
Filip Hrbáček ◽  
Kamil Láska
Keyword(s):  
Heat Flux ◽  
Surface Energy ◽  
Energy Budget ◽  
Thermal Regime ◽  
Sensible Heat Flux ◽  
Ground Surface ◽  
Surface Energy Budget ◽  
Net Radiation ◽  
Ground Heat Flux ◽  
James Ross Island

Despite the key role of the surface energy budget in the global climate system, such investigations are rare in Antarctica. In this study, the surface energy budget measurements from the largest ice-free area on northern James Ross Island, in Antarctica, were obtained. The components of net radiation were measured by a net radiometer, while sensible heat flux was measured by a sonic anemometer and ground heat flux by heat flux plates. The surface energy budget was compared with the rest of the Antarctic Peninsula Region and selected places in the Arctic and the impact of surface energy budget components on the ground thermal regime was examined. Mean net radiation on James Ross Island during January–March 2018 reached 102.5 W m−2. The main surface energy budget component was the latent heat flux, while the sensible heat flux values were only 0.4 W m−2 lower. Mean ground heat flux was only 0.4 Wm-2, however, it was negative in 47% of January–March 2018, while it was positive in the rest of the time. The ground thermal regime was affected by surface energy budget components to a depth of 50 cm. The strongest relationship was found between ground heat flux and ground surface temperature. Further analysis confirmed that active layer refroze after a sequence of three days with negative ground heat flux even in summer months. Daily mean net radiation and ground heat flux were significantly reduced when cloud amount increased, while the influence of snow cover on ground surface temperature was negligible.

scholarly journals Shift in seasonal snowpack melt-out date due to light-absorbing particles at a high-altitude site in Central Himalaya

2021 ◽  
Author(s):  
Johan Ström ◽  
Jonas Svensson ◽  
Henri Honkanen ◽  
Eija Asmi ◽  
Nathaniel B. Dkhar ◽  
...  
Keyword(s):  
High Altitude ◽  
Snow Cover ◽  
Energy Budget ◽  
Snow Water Equivalent ◽  
Base Case ◽  
Snow Melt ◽  
Central Himalayas ◽  
Seasonal Snow ◽  
The Impact ◽  
Seasonal Snow Cover

Abstract. Snow darkening by deposited light-absorbing particles (LAP) has the potential to accelerate snowmelt and shift the snow melt-out date. Here we investigate the sensitivity of the seasonal snow cover duration to changes in LAP at a high altitude valley site in the Central Himalayas, India. First, the variation of the albedo of the seasonal snow was emulated using two seasons of automatic weather station (AWS) data and applying a constant, but realistic deposition of LAP to the snow. Then, the number of days with snowmelt were evaluated based on the estimated net energy budget of the seasonal snow cover and the derived surface temperature. The impact on the energy budget by LAP combined with the melt-day analysis resulted in very simple relations to determine the contribution of LAP to the number of days with snowmelt of the seasonal snow in Himalaya. Above a concentration of 1 ng g-1 (Elemental Carbon equivalent, ECeq, which in this study includes EC and the absorption equivalent EC contribution by other light absorbing particles, such as mineral dust) in new snow, the number of days with snowmelt can be estimated by; days=0.0109(log⁡(〖EC〗_eq )+1)PP±0.0033(log⁡(〖EC〗_eq )+1)PP, where PP is the seasonal precipitation in mm snow water equivalent. A change in ECeq by a factor of two corresponds to about 1/3 of a day per 100 mm precipitation. Although the change in the number of days with melt caused by the changes in ECeq is small, the estimated total change in the snow melt-out date by LAP can be significant. For our realistic base case scenario for the Sunderdhunga Valley, Central Himalayas, India, of ECeq=100 ng g-1 and PP=400 mm, this yields in an advancement of the melt-out date of about 13 days.

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