scholarly journals What are the key drivers of regional differences in the water balance on the Tibetan Plateau?

2015 ◽  
Vol 12 (4) ◽  
pp. 4271-4314 ◽  
Author(s):  
S. Biskop ◽  
F. Maussion ◽  
P. Krause ◽  
M. Fink
Keyword(s):  
Tibetan Plateau ◽  
Water Balance ◽  
Hydrological Modeling ◽  
Integrated Approach ◽  
Water Levels ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Water Balance Components ◽  
South Central ◽  
Lake Basins

Abstract. Lake-level fluctuations in closed basins on the Tibetan Plateau (TP) indicate climate-induced changes in the regional water balance. However, little is known about the region's key hydrological parameters, hampering the interpretation of these changes. The purpose of this study is to contribute to a more quantitative understanding of these controls. Four lakes in the south-central part of the TP were selected to analyze the spatiotemporal variations of water-balance components: Nam Co and Tangra Yumco (indicating increasing water levels), and Mapam Yumco and Paiku Co (indicating stable or slightly decreasing water levels). We present the results of an integrated approach combining hydrological modeling, atmospheric-model output and remote-sensing data. The hydrological model J2000g was adapted and extended according to the specific characteristics of closed lake basins on the TP and driven with "High Asia Refined analysis (HAR)" data at 10 km resolution for the period 2001–2010. Our results reveal that because of the small portion of glacier areas (1 to 7% of the total basin area) the contribution of glacier melt water accounts for only 14–30% of total runoff during the study period. Precipitation is found to be the principal factor controlling the water-balance in the four studied basins. The positive water balance in the Nam Co and Tangra Yumco basins was primarily related to larger precipitation amounts and thus higher runoff rates in comparison with the Paiku Co and Mapam Yumco basins. This study highlights the benefits of combining atmospheric and hydrological modeling. The presented approach can be readily transferred to other ungauged lake basins on the TP, opening new directions of research. Future work should go towards increasing the atmospheric model's spatial resolution and a better assessment of the model-chain uncertainties, especially in this region where observational data is missing.

scholarly journals Differences in the water-balance components of four lakes in the southern-central Tibetan Plateau

2016 ◽  
Vol 20 (1) ◽  
pp. 209-225 ◽  
Author(s):  
S. Biskop ◽  
F. Maussion ◽  
P. Krause ◽  
M. Fink
Keyword(s):  
Water Balance ◽  
Hydrological Modeling ◽  
Hydrological Model ◽  
Atmospheric Model ◽  
Water Levels ◽  
Model Output ◽  
Runoff Generation ◽  
Nam Co ◽  
Southern Central ◽  
Closed Lake

Abstract. The contrasting patterns of lake-level fluctuations across the Tibetan Plateau (TP) are indicators of differences in the water balance over the TP. However, little is known about the key hydrological factors controlling this variability. The purpose of this study is to contribute to a more quantitative understanding of these factors for four selected lakes in the southern-central part of the TP: Nam Co and Tangra Yumco (increasing water levels), and Mapam Yumco and Paiku Co (stable or slightly decreasing water levels). We present the results of an integrated approach combining hydrological modeling, atmospheric-model output and remote-sensing data. The J2000g hydrological model was adapted and extended according to the specific characteristics of closed-lake basins on the TP and driven with High Asia Refined analysis (HAR) data at 10 km resolution for the period 2001–2010. Differences in the mean annual water balances among the four basins are primarily related to higher precipitation totals and attributed runoff generation in the Nam Co and Tangra Yumco basins. Precipitation and associated runoff are the main driving forces for inter-annual lake variations. The glacier-meltwater contribution to the total basin runoff volume (between 14 and 30 % averaged over the 10-year period) plays a less important role compared to runoff generation from rainfall and snowmelt in non-glacierized land areas. Nevertheless, using a hypothetical ice-free scenario in the hydrological model, we indicate that ice-melt water constitutes an important water-supply component for Mapam Yumco and Paiku Co, in order to maintain a state close to equilibrium, whereas the water balance in the Nam Co and Tangra Yumco basins remains positive under ice-free conditions. These results highlight the benefits of linking hydrological modeling with atmospheric-model output and satellite-derived data, and the presented approach can be readily transferred to other data-scarce closed lake basins, opening new directions of research. Future work should go towards a better assessment of the model-chain uncertainties, especially in this region where observation data are scarce.

Potential forcing mechanisms of Holocene lake-level changes at Nam Co, Tibetan Plateau: Inferred from the stable isotopic composition of shells of the gastropod Radix

The Holocene ◽  
2016 ◽  
Vol 27 (4) ◽  
pp. 594-604 ◽  
Author(s):  
Feng Chen ◽  
Jin-Liang Feng ◽  
Hai-Ping Hu ◽  
Ji-Feng Zhang ◽  
Shao-Peng Gao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Lake Level ◽  
Late Holocene ◽  
Causal Mechanism ◽  
The Tibetan Plateau ◽  
The South ◽  
Large Area ◽  
Nam Co ◽  
Lake Level Changes ◽  
South Central

The timing of lake-level fluctuations on the Tibetan Plateau and their relationship with climatic changes is still under debate, and the main reason for this is the lack of suitable archives for reconstructing the paleohydrology and paleoclimatology of the lakes. Here, we present the results of analyses of the shell geochemistry of Radix sp. from an exposed terrace of Nam Co lake on the south-central Tibetan Plateau. Optically stimulated luminescence (OSL) dating reveals that deep-water lacustrine sediments formed between ca. 4.4 and 2.2 ka, suggesting a high and stable lake level significantly above the present. The results of Sr/Ca, δ13C and δ18O analyses of the fossil shells of Radix sp. indicate that during the mid- to late-Holocene, lake-level variations in Nam Co were mainly controlled by variations in the Indian Summer Monsoon. A trend of decreasing evaporation also played an important role. Comparison with other results suggests a consistent pattern of mid- to late-Holocene lake-level changes across a large area of the Tibetan Plateau and adjacent regions to the south, which had a similar causal mechanism. Finally, our results indicate that fossil shells of the gastropod Radix sp. of the lakes on the Tibetan Plateau are a valuable archive for reconstructing the regional paleohydrology and paleoclimatology.

Rapid growth of the Bar-headed Goose Anser indicus wintering population in Tibet, China: 1991–2017

2021 ◽  
pp. 1-16
Author(s):  
MARY ANNE BISHOP ◽  
DONGPING LIU ◽  
GUOGANG ZHANG ◽  
DROLMA TSAMCHU ◽  
LE YANG ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Winter Wheat ◽  
Population Growth ◽  
Water Levels ◽  
The Tibetan Plateau ◽  
Annual Growth Rate ◽  
South Central ◽  
Tibet Autonomous Region ◽  
Breeding Grounds ◽  
Wintering Population

Summary Four of China’s six wintering populations of “grey” geese Anser spp. declined during the last decade. In contrast, the Bar-headed Goose A. indicus wintering population in China’s Tibet Autonomous Region more than doubled. During six surveys in Tibet over a 27-year period (1991/92 to 2017/18 winters) we documented an annual growth rate of 6.8% in the Bar-headed Goose population – an increase from approximately 10,100 to 68,100 birds. We propose that in addition to the cessation of hunting, the population growth of Bar-headed Goose is being driven by changes in agricultural land use patterns in Tibet, the establishment of protected areas on the wintering and breeding grounds, and the impacts of climate change across the Tibetan Plateau. Consistent with this hypothesis, the sown area of winter wheat in Tibet has increased and geese have shifted from primarily feeding in crop stubble to planted winter wheat fields. We also found that the most rapid population growth coincided with a 1998 climate regime shift across the Tibetan Plateau resulting in warmer temperatures, an increase in net precipitation, the appearance of new lakes and changes in the water levels and surface area of historical lakes. We suggest that warmer temperatures and high-quality forage on the south-central Tibet wintering grounds may be enhancing over-winter survival, while on the breeding grounds the expansion of lakes and wet meadows is augmenting breeding and brood-rearing habitat.

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

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1412
Author(s):  
Tuong Vi Tran ◽  
Johannes Buckel ◽  
Philipp Maurischat ◽  
Handuo Tang ◽  
Zhengliang Yu ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Tibetan Plateau ◽  
Field Experiments ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Field Methods ◽  
Climate Conditions ◽  
South Central

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.

scholarly journals Hydrological system analysis and modelling of the Nam Co basin in Tibet

2010 ◽  
Vol 27 ◽  
pp. 29-36 ◽  
Author(s):  
P. Krause ◽  
S. Biskop ◽  
J. Helmschrot ◽  
W.-A. Flügel ◽  
S. Kang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Water Balance ◽  
Lake Level ◽  
Global Climate ◽  
The Tibetan Plateau ◽  
Nam Co ◽  
Ice Melt ◽  
Hydrological System ◽  
Nam Co Basin ◽  
Snow And Ice Melt

Abstract. The Tibetan Plateau and the adjacent high mountain regions of the Himalayas play an important role in the global climate dynamic through its impact on the Asian monsoon system, which in turn is impacting the water resources of this extremely vulnerable region. To provide further knowledge about the changing impact of rainfall patterns, spatial and temporal variability of snow cover contribution, amount of snow and ice melt runoff, evapotranspiration as well as dynamics of wetlands and permafrost water balance studies are required. This is of particular importance in terms of global climate change because of a severe gap in the knowledge of the short, mid and long term implications on the hydrological system. This study concentrates on the macroscale catchment of the lake Nam Co, located at 4718 m a.s.l. at the foot of the Nyainqentanglha Mountains in central Tibet (30° N, 90° E). The water balance of the Nam Co basin is dominated by semi-arid climate, snow and ice melt runoff and high evaporation rates due to the high radiation input and the low air humidity. The observed temperature rise, glacier retreat, permafrost decay and lake level increase indicate significant system changes and the high sensitivity of the Tibetan Plateau on global warming. The development of a suitable water balance model and its preliminary application was the main objective of this study. The development was done with the Jena Adaptable Modelling System JAMS along with existing scientific process components of the J2000 module library which were partly further developed to reflect the specific conditions of the high elevation Nam Co basin. The preliminary modelling exercise based on gridded data from a downscaled ECHAM5 data set provided reasonable estimates about the important hydrological water balance components of the Nam Co basin. With the modelling results the observed lake level rise could be reproduced and it could be shown that the runoff from the glaciered areas seems to be the most important component to explain the increasing amount of lake water.

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.

scholarly journals Atmospheric processes of persistent organic pollutants over a remote lake of the central Tibetan Plateau: Implications for regional cycling

2016 ◽  
Author(s):  
Jiao Ren ◽  
Xiaoping Wang ◽  
Chuanfei Wang ◽  
Ping Gong ◽  
Tandong Yao
Keyword(s):  
Tibetan Plateau ◽  
Organic Pollutants ◽  
Persistent Organic Pollutants ◽  
Secondary Source ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
Nam Co ◽  
Surface Exchange ◽  
Atmospheric Processes ◽  
Water Gas

Abstract. Atmospheric processes (air-surface exchange, and atmospheric deposition and degradation) are crucial for understanding the global cycling and fate of persistent organic pollutants (POPs). However, such assessment over the Tibetan Plateau (TP) remains uncertain. More than 50 % of the Chinese lakes are located on the TP, which exerts a remarkable influence on the regional water, energy, and chemical cycling. In this study, air and water samples were simultaneously collected in Nam Co, a large lake on the TP, to test whether the lake is a "secondary source" or "sink" of POPs. Lower concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) were observed in the atmosphere and lake water of Nam Co, while the levels of polycyclic aromatic hydrocarbons (PAHs) were relatively higher. Results of fugacity ratios and chiral signatures both suggest that the lake acted as the net sink of atmospheric hexachlorocyclohexanes (HCHs), following their long-range transport driven by the Indian Monsoon. Different behaviors were observed in the PAHs, which primarily originated from local biomass burning. Acenaphthylene, acenaphthene, and fluorene showed volatilization from the lake to the atmosphere; while other PAHs were deposited into the lake due to the integrated deposition process (wet/dry and air-water gas deposition) and limited atmospheric degradation. As the dominant PAH compound, phenanthrene exhibited a seasonal reversal of air-water gas exchange, which was likely related to the melting of the lake ice in May. The annual input of HCHs from air to the entire lake area (2015 km2) was estimated as 1.9 kg year−1, while those estimated for PAHs can potentially reach up to 550 kg year−1. This study highlights the significance of PAH deposition on the regional carbon cycling in the oligotrophic lakes of the TP.

scholarly journals Air-Lake Interaction Features Found in Heat and Water Exchanges over Nam Co on the Tibetan Plateau

SOLA ◽  
2009 ◽  
Vol 5 ◽  
pp. 172-175 ◽  
Author(s):  
Shigenori Haginoya ◽  
Hideyuki Fujii ◽  
Tsuneo Kuwagata ◽  
Jianqing Xu ◽  
Yasushi Ishigooka ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Nam Co
Sign in / Sign up

Export Citation Format

Share Document