scholarly journals Observed and Simulated Lake Effect Precipitation Over the Tibetan Plateau: An Initial Study at Nam Co Lake

2018 ◽  
Vol 123 (13) ◽  
pp. 6746-6759 ◽  
Author(s):  
Yufeng Dai ◽  
Lei Wang ◽  
Tandong Yao ◽  
Xiangyu Li ◽  
Lingjing Zhu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Initial Study ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Lake Effect ◽  
Nam Co Lake

Evaporation variability of Nam Co Lake in the Tibetan Plateau and its role in recent rapid lake expansion

2016 ◽  
Vol 537 ◽  
pp. 27-35 ◽  
Author(s):  
Ning Ma ◽  
Jozsef Szilagyi ◽  
Guo-Yue Niu ◽  
Yinsheng Zhang ◽  
Teng Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Nam Co Lake

Long-Term Changes of Lake Level and Water Budget in the Nam Co Lake Basin, Central Tibetan Plateau

2014 ◽  
Vol 15 (3) ◽  
pp. 1312-1322 ◽  
Author(s):  
Yanhong Wu ◽  
Hongxing Zheng ◽  
Bing Zhang ◽  
Dongmei Chen ◽  
Liping Lei
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Water Budget ◽  
Lake Level ◽  
Lake Basin ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Long Term Changes ◽  
Nam Co Lake

Abstract Long-term changes in the water budget of lakes in the Tibetan Plateau due to climate change are of great interest not only for the importance of water management, but also for the critical challenge due to the lack of observations. In this paper, the water budget of Nam Co Lake during 1980–2010 is simulated using a dynamical monthly water balance model. The simulated lake level is in good agreement with field investigations and the remotely sensed lake level. The long-term hydrological simulation shows that from 1980 to 2010, lake level rose from 4718.34 to 4724.93 m, accompanied by an increase of lake water storage volume from 77.33 × 109 to 83.66 × 109 m3. For the net lake level rise (5.93 m) during the period 1980–2010, the proportional contributions of rainfall–runoff, glacier melt, precipitation on the lake, lake percolation, and evaporation are 104.7%, 56.6%, 41.7%, −22.2%, and −80.9%, respectively. A positive but diminishing annual water surplus is found in Nam Co Lake, implying a continuous but slowing rise in lake level as a hydrological consequence of climate change.

scholarly journals Turbulent flux modelling with a simple 2-layer soil model and extrapolated surface temperature applied at Nam Co Lake basin on the Tibetan Plateau

2012 ◽  
Vol 16 (4) ◽  
pp. 1095-1110 ◽  
Author(s):  
T. Gerken ◽  
W. Babel ◽  
A. Hoffmann ◽  
T. Biermann ◽  
M. Herzog ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Surface Temperature ◽  
Temperature Profile ◽  
Circulation Model ◽  
Surface Model ◽  
Lake Basin ◽  
Base Temperature ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Nam Co Lake

Abstract. This paper introduces a surface model with two soil-layers for use in a high-resolution circulation model that has been modified with an extrapolated surface temperature, to be used for the calculation of turbulent fluxes. A quadratic temperature profile based on the layer mean and base temperature is assumed in each layer and extended to the surface. The model is tested at two sites on the Tibetan Plateau near Nam Co Lake during four days during the 2009 Monsoon season. In comparison to a two-layer model without explicit surface temperature estimate, there is a greatly reduced delay in diurnal flux cycles and the modelled surface temperature is much closer to observations. Comparison with a SVAT model and eddy covariance measurements shows an overall reasonable model performance based on RMSD and cross correlation comparisons between the modified and original model. A potential limitation of the model is the need for careful initialisation of the initial soil temperature profile, that requires field measurements. We show that the modified model is capable of reproducing fluxes of similar magnitudes and dynamics when compared to more complex methods chosen as a reference.

scholarly journals Black Carbon: The Concentration and Sources Study at the Nam Co Lake, the Tibetan Plateau from 2015 to 2016

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 624 ◽  
Author(s):  
Feiteng Wang ◽  
Xin Zhang ◽  
Xiaoying Yue ◽  
Mengyuan Song ◽  
Guoshuai Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Black Carbon ◽  
Animal Manure ◽  
Average Concentration ◽  
Tourism Industry ◽  
Atmospheric Environment ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Long Distance ◽  
Nam Co Lake

We measured black carbon (BC) with a seven-wavelength aethalometer (AE-31) at the Nam Co Lake (NCL), the hinterland of the Tibetan Plateau (TP) from May 2015 to April 2016. The daily average concentration of BC was 145 ± 85 ng m−3, increasing by 50% since 2006. The seasonal variation of BC shows higher concentrations in spring and summer and lower concentrations in autumn and winter, dominated by the adjacent sources and meteorological conditions. The diurnal variation of BC showed that its concentrations peaked at 9:00–16:00 (UTC + 8), significantly related to local human activities (e.g., animal-manure burning and nearby traffic due to the tourism industry). The concentration-weighted trajectory (CWT) analysis showed that the long-distance transport of BC from South Asia could also be a potential contributor to BC at the NCL, as well as the biomass burning by the surrounding residents. The analyses of the absorption coefficient and absorption Ångström exponent show the consistency of sourcing the BC at the NCL. We suggest here that urgent measures should be taken to protect the atmospheric environment at the NCL, considering the fast-increasing concentrations of BC as an indicator of fuel combustion.

scholarly journals Precipitation Dominates Long-Term Water Storage Changes in Nam Co Lake (Tibetan Plateau) Accompanied by Intensified Cryosphere Melts Revealed by a Basin-Wide Hydrological Modelling

2020 ◽  
Vol 12 (12) ◽  
pp. 1926
Author(s):  
Xiaoyang Zhong ◽  
Lei Wang ◽  
Jing Zhou ◽  
Xiuping Li ◽  
Jia Qi ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Water Storage ◽  
Hydrological Processes ◽  
Lake Basin ◽  
Water Runoff ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Glacier Melting ◽  
Nam Co Lake

Lakes on the Tibetan Plateau (TP) have changed dramatically as a result of climate change during recent decades. Studying the changes in long-term lake water storage (LWS) is of great importance for regional water security and ecosystems. Nam Co Lake is the second largest lake in the central TP. To investigate the long-term changes in LWS, a distributed cryosphere-hydrology model (WEB-DHM) driven by multi-source data was evaluated and then applied to simulate hydrological processes across the whole Nam Co Lake basin from 1980 to 2016. Firstly, a comparison of runoff (lake inflow), land surface temperature, and snow depth between the model simulations and observations or remote sensing products showed that WEB-DHM could accurately simulate hydrological processes in the basin. Meanwhile, the simulated daily LWS was in good agreement with satellite-derived data during 2000–2016. Secondly, long-term simulations showed that LWS increased by 9.26 km3 during 1980–2016, reaching a maximum in 2010 that was 10.25 km3 greater than that in 1980. During this period, LWS firstly decreased (1980–1987), then increased (1988–2008), and decreased again (2009–2016). Thirdly, the contributions of precipitation runoff, melt-water runoff, lake surface precipitation, and lake evaporation to Nam Co LWS were 71%, 33%, 24%, and -28%, respectively. Snow and glacier melting have significantly intensified during recent decades (2.96 m3 s−1/decade on average), contributing a mean proportion of 22% of lake inflows. These findings are consistent with the significant increasing trends of annual precipitation and temperature in the lake basin (25 mm/decade and 0.4 K/decade, respectively). We conclude that long-term variations in Nam Co LWS during 1980–2016 were largely controlled by precipitation; however, the contribution of precipitation runoff to total lake inflow has decreased while the contribution from warming-induced snow and glacier melting has significantly increased.

Ostracod-based environmental reconstruction over the last 8,400 years of Nam Co Lake on the Tibetan plateau

Hydrobiologia ◽  
2010 ◽  
Vol 648 (1) ◽  
pp. 157-174 ◽  
Author(s):  
Liping Zhu ◽  
Ping Peng ◽  
Manping Xie ◽  
Junbo Wang ◽  
Peter Frenzel ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Environmental Reconstruction ◽  
Nam Co ◽  
Nam Co Lake

Hydrothermal pattern of frozen soil in Nam Co lake basin, the Tibetan Plateau

2008 ◽  
Vol 57 (8) ◽  
pp. 1775-1784 ◽  
Author(s):  
Keming Tian ◽  
Jingshi Liu ◽  
Shichang Kang ◽  
Iain B. Campbell ◽  
Fei Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Frozen Soil ◽  
Lake Basin ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Nam Co Lake

scholarly journals Turbulent flux modelling with a simple 2-layer soil model and extrapolated surface temperature applied at Nam Co Lake basin on the Tibetan Plateau

2011 ◽  
Vol 8 (6) ◽  
pp. 10275-10309
Author(s):  
T. Gerken ◽  
W. Babel ◽  
A. Hoffmann ◽  
T. Biermann ◽  
M. Herzog ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Surface Temperature ◽  
Temperature Profile ◽  
Circulation Model ◽  
Surface Model ◽  
Lake Basin ◽  
Base Temperature ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Nam Co Lake

Abstract. This paper introduces a surface model with two soil-layers for use in a high-resolution circulation model that has been modified with an extrapolated surface temperature, to be used for the calculation of turbulent fluxes. A quadratic temperature profile based on the layer mean and base temperature is assumed in each layer and extended to the surface. The model is tested at two sites on the Tibetan Plateau near Nam Co Lake during four days during the 2009 Monsoon season. In comparison to a two-layer model without explicit surface temperature estimate, there is a greatly reduced delay in diurnal flux cycles and the modelled surface temperature is much closer to observations. Comparison with a SVAT model and eddy covariance measurements shows an overall reasonable model performance based on RMSD and cross correlation comparisons between the modified and original model. A potential limitation of the model is the need for careful initialisation of the initial soil temperature profile, that requires field measurements. We show that the modified model is capable of reproducing fluxes of similar magnitudes and dynamics as the more complex methods chosen as reference.

Aquifer parameter estimation for the Zhagu subcatchment (Tibetan Plateau) based on geophysical methods

2020 ◽  
Author(s):  
Tuong Vi Tran ◽  
Johannes Buckel ◽  
Philipp Maurischat ◽  
Handuo Tang ◽  
Zhengliang Yu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Water Supply ◽  
Pore Water ◽  
Geophysical Methods ◽  
Field Work ◽  
The Tibetan Plateau ◽  
Sediment Layer ◽  
Nam Co ◽  
Aquifer Parameter ◽  
Nam Co Lake

<p>The aquifers on the Tibetan Plateau (TP) constitute as origin for major river systems, which are supplying millions of people all over Asia. Increasing population and tourism activities leading to larger water consumption. Hence, water supply is getting increasingly important. The TP is a sensitive system and is noticeable reacting climate change. Past decades are marked with, increasing trends of precipitation, melting of glaciers and degradation of permafrost and have generally lead to rising water levels in lakes on the TP. To ensure future water supply, aquifer characterisation and future prognosis on groundwater behavior are therefore necessary. However, due to the remote character of the TP, knowledge according to hydrogeological parameter is scarce. The aim of this study is therefore to estimate a range for aquifer parameter based on geophysical methods. The Zhagu basin, situated in the Nam Co Lake basin (second largest lake on the TP), is used as a case study. This project is part of the International Research Training Group “Geoecosystems in transition on the Tibetan Plateau” (TransTiP), funded by the DFG.</p><p>During several field work campaign in July 2018, May 2019 and September 2019 disturbed sediment samples were taken and were analyzed for grain size distribution. Selected sediment layer in the laboratory were tested. Outcome of this analysis is the porosity for each selected sediment layer. Another measurement during field work has been conducted, namely electrical resistivity tomography measurements (ERT). To get better approximation of porosity and sediment characteristics, Archie’s Law is used as model to estimate those properties and later on to compare it to field and laboratory results. Two approaches are implemented (i) calculates the bulk resistivity based on known porosity from the laboratory and known conductivity of pore water measured during field work (ii) calculates the porosity with known conductivity of pore water and the bulk conductivity. For analysis saturated sediment layers were chosen.</p><p>The investigation shows that both approaches are largely applicable and leading to almost same results and trends of each sediment layer. The best percentage deviation of the modeled bulk resistivity results to the measurement in the field could be achieved by position D11 which is situated near the Nam Co Lake showing a deviation of around 7%. Inside the catchment the percentage deviation is largely increasing. However, the application of Archie’s Law in combination with field and laboratory measurements allows to construct a porosity ranges for future groundwater flow calibration. In addition, the results emphasising the zonation of the subsurface in (un)saturated zones due to the small amount of resistivity.</p><p>Sediment profiles, ERT measurements, observations, interpretation and conclusion including the comparison of simulated resistivity and simulated porosity to field resistivity and porosity based on laboratory analysis will be shown and discussed in the contribution.</p>

scholarly journals Surface ozone at Nam Co (4730 m a.s.l.) in the inland Tibetan Plateau: variation, synthesis comparison and regional representativeness

2017 ◽  
Author(s):  
Xiufeng Yin ◽  
Shichang Kang ◽  
Benjamin de Foy ◽  
Zhiyuan Cong ◽  
Jiali Luo ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Surface Ozone ◽  
Early Morning ◽  
Photochemical Reactions ◽  
Transport Processes ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Mixing Ratios ◽  
Northern Tibetan Plateau ◽  
Ozone Levels

Abstract. Ozone is an important pollutant and greenhouse gas, and tropospheric ozone variations are generally associated with both natural and anthropogenic processes. As one of the most pristine and inaccessible regions in the world, the Tibetan Plateau has been considered as an ideal region for studying processes of the background atmosphere. Due to the vast area of the Tibetan Plateau, sites in the southern, northern and central regions exhibit different patterns of variation in surface ozone. Here, we present long-term measurements for ~ 5 years (January 2011 to October 2015) of surface ozone mixing ratios at Nam Co Station, which is a regional background site in the inland Tibetan Plateau. An average surface ozone mixing ratio of 47.6 ± 11.6 ppb was recorded, and a large annual cycle was observed with maximum ozone mixing ratios in the spring and minimum ratios during the winter. The diurnal cycle is characterized by a minimum in the early morning and a maximum in the late afternoon. Nam Co Station represents a background region where surface ozone receives negligible local anthropogenic emissions. Surface ozone at Nam Co Station is mainly dominated by natural processes involving photochemical reactions and potential local vertical mixing. Model results indicate that the study site is affected by the surrounding areas in different seasons and that air masses from the northern Tibetan Plateau lead to increased ozone levels in the summer. In contrast to the surface ozone levels at the edges of the Tibetan Plateau, those at Nam Co Station are less affected by stratospheric intrusions and human activities which makes Nam Co Station representative of vast background areas in the central Tibetan Plateau. By comparing measurements at Nam Co Station with those from other sites in the Tibetan Plateau and beyond, we aim to expand the understanding of ozone cycles and transport processes over the Tibetan Plateau. This work may provide a reference for model simulations in the future.

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