scholarly journals COMPARISON OF CRYOSAT-2 AND ICESAT-2 ON WATER LEVEL MONITORING OF NAM CO LAKE

2021 ◽  
Vol XLIII-B3-2021 ◽  
pp. 527-532
Author(s):  
H. Zhao ◽  
R. Xu ◽  
G. Qiao
Keyword(s):  
Water Level ◽  
Lake Level ◽  
The Tibetan Plateau ◽  
Lake Levels ◽  
Nam Co ◽  
Important Indicator ◽  
Annual Changes ◽  
Nam Co Lake ◽  
Level Monitoring ◽  
Water Level Monitoring

Abstract. There are more than 1,000 lakes (> 1 km2) on the Tibetan Plateau and lake level is an important physical feature of lake changes. Lake level change is an important indicator to reflect changes of climate and environment in a certain area. The development of satellite altimetry has provided data support for the monitoring of lake level and effectively compensated for the deficiencies of traditional water level monitoring in alpine regions. In this study, the laser altimeter of ICESat-2 and the radar altimeter of CryoSat-2 are used to provide lake level of the Nam Co lake during the period of 2010–2020. The result showed that the standard deviation (SD) of ICESat-2 (0.0895 m) was lower than the SD of CryoSat-2 (0.2556 m) and the months with higher SD values were mostly during the ice period of Nam Co lake. ICESat-2 had a considerably decreased measurement uncertainty. There are systematic differences in lake levels extracted by different altimetry satellites and the mean bias between ICESat-2 and CryoSat-2 was around 0.45 m. After removing inter-altimeter biases, the continuous lake levels from 2010 to 2020 were constructed. The inter-annual changes in lake levels were flat or even slightly decreased and the lake level has dropped by about 0.80 m in general. The water level generally reached the highest from September to October of the year in terms of intra-annual changes. Besides, temperature and precipitation changes were closely related to lake level tendency.

scholarly journals Variations in water level and glacier mass balance in Nam Co lake, Nyainqentanglha range, Tibetan Plateau, based on ICESat data for 2003-09

2014 ◽  
Vol 55 (66) ◽  
pp. 239-247 ◽  
Author(s):  
Hongbo Wu ◽  
Ninglian Wang ◽  
Xi Jiang ◽  
Zhongming Guo
Keyword(s):  
Tibetan Plateau ◽  
Mass Balance ◽  
Water Level ◽  
Lake Level ◽  
Altimeter Data ◽  
Glacier Mass Balance ◽  
Lake Area ◽  
Nam Co ◽  
Glacier Meltwater ◽  
Nam Co Lake

AbstractWater level fluctuations of inland lakes are related to regional-scale climate changes, and reflect variations in evaporation, precipitation and glacier meltwater flowing into the lake area in its catchment. In this paper, Ice, Cloud and land Elevation Satellite (ICESat) altimeter data and Landsat imagery (2002-09) are used to estimate Nam Co lake (Nyainqentanglha range, Tibetan Plateau) water elevation changes during 2002-09. In 2003 Nam Co lake covered an area of ~1998.8 ± 4.2 km2 and was situated at 4723 m a.s.l. Over such inland water bodies, ICESat altimeter data offer both wide coverage and spatial and temporal accuracy. We combine remote-sensing and GIS technology to map and reconstruct lake area and increased volume changes during a 7 year time series. Nam Co lake water level increased by 2.4±0.12m (0.33ma–1) between 23 February 2003 and 1 October 2009, and lake volume increased by 4.9 ±0.5 km3. In the past 7 years, Nam Co lake area has increased from 1998.78 ±5.4 to 2023.8 ±3.4 km2, the glacier-covered area has decreased from 832.34 to 821.0 km2 and the drainage basin area has decreased from 201.1 ±4.2 to 196.1 ±2.3 km2. However, the most spectacular feature is the continual water level rise from 2003 to 2009 without an obvious associated increase in precipitation. Based on digital elevation models (DEMs) from Shuttle Radar Topography Mission (SRTM) DEM data and corrected ICESat elevation data, significant changes to glacier mass balance in the western Nyainqentanglha mountains are indicated. Nyainqentanglha mountain glacier surface elevations decreased by 8.39 ± 0.45 m during 2003-09. Over the same period, at least 1.01 km3 of glacial meltwater flowed into Nam Co lake, assuming a glacial runoff coefficient of 0.6. The mean glacier mass-balance value is -490mmw.e. over the corresponding period, indicating that glacier meltwater in the catchment contributes to lake level rise. The contribution rate of glacial meltwater to lake water volume rise is 20.75%. The temporal lake level fluctuation correlates with temperature variations over the same time span.

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.

Mechanism of Lake Area Variations and Water Level Changes in Nam Co Lake

2013 ◽  
Vol 838-841 ◽  
pp. 1685-1692 ◽  
Author(s):  
Yan Du ◽  
Mo Wen Xie ◽  
Man Hu
Keyword(s):  
Water Level ◽  
Linear Regression Analysis ◽  
Geographical Location ◽  
Seepage Flow ◽  
Tibet Plateau ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
Nam Co ◽  
Long Time ◽  
Nam Co Lake

The Tibetan Plateau is one of the best areas for the study because of its geographical location as well as human disturbance. AS one of the largest lakes in the Qinghai-Tibet Plateau, Nam Co Lake seepage underestimated for a long time. By linear regression analysis of hydrological data from 1970-2005, we qualitatively understands the water level operation mechanism. The result shows that the model deviates from 2000, compared with the actual water level. Correlation analysis indicates the Nam Co Lake seepage flow reduces after 2000. The Three Gorges project resulted in the uplift of the downstream water level, which exacerbates the rise of water level of Nam Co Lake. Owing to the non timeliness of underground seepage recharge, water level of downstream lake is difficult to simulate. According to the result and recent research, underground seepage may be a cycle, affecting the water level of all the lakes.

scholarly journals Recent Abnormal Hydrologic Behavior of Tibetan Lakes Observed by Multi-Mission Altimeters

2020 ◽  
Vol 12 (18) ◽  
pp. 2986
Author(s):  
Pengfei Zhan ◽  
Chunqiao Song ◽  
Jida Wang ◽  
Wenkai Li ◽  
Linghong Ke ◽  
...  
Keyword(s):  
Water Level ◽  
Lake Level ◽  
Average Rate ◽  
Water Levels ◽  
The Tibetan Plateau ◽  
Important Indicator ◽  
Water Level Rise ◽  
Lake Level Changes ◽  
Spatial Differences ◽  
Climate Analysis

Inland lakes in the Tibetan Plateau (TP) with closed catchments and minimal human disturbance are an important indicator of climate change. However, the examination of changes in the spatiotemporal patterns of Tibetan lakes, especially water level variations, is limited due to inadequate access to measurements. This obstacle has been improved by the development of satellite altimetry observations. The more recent studies revealed that the trend of central TP to grow decreased or reversed between 2010 and 2016. However, thus far, this trend has not been investigated to determine whether this pattern would last for the following years. This study aims to combine the traditional (launched before 2010, e.g., TOPEX/POSEIDON, ERS-1, ERS-2, Jason-1/-2, and Envisat) and recently advanced (launched after 2010, e.g., SARAL and Sentinel-3) altimetry observations to understand the Tibetan lake changes further in recent years. Therefore, we acquired information on the continuous lake level changes in Tibetan lakes using the lake level sequence integration method based on multisource altimetry satellites. The results revealed that water level changes in 22 examined lakes showed abrupt rises in 2016–2018, but the onsets and magnitudes of the rises varied among the lakes. During the study period, the water levels of the lakes (except Nam Co) revealed a drastic rising tendency with a mean rate of 0.74 m/a, which was remarkably higher than the average rate of water level rise over the period 2010–2015 (approximately 0.28 m/a). Specifically, the water level of the nine lakes in the Northern TP (NTP) displayed a significant rising trend, with an average rate of 0.82 m/a. In the Central TP (CTP), the lake level changes were generally divided into two categories. The water levels for the lakes in the Western CTP rose rapidly, while, in the Eastern CTP, the lake water levels rose slowly, with an average rising rate less than 0.40 m/a. The water levels for the lakes in the Northeastern TP (NETP) and Northwestern TP (NWTP) kept a stable rising tendency. According to the results of the climate analysis, the spatial differences of the lake level rise rates were primarily caused by the spatial and temporal changes of precipitation over the TP.

AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

2019 ◽  
pp. 95-103
Author(s):  
Krum Videnov ◽  
Vanya Stoykova
Keyword(s):  
Water Level ◽  
Real Time ◽  
Early Warning ◽  
Water Sources ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Level Monitoring ◽  
Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

scholarly journals A High-Accuracy and Power-Efficient Self-Optimizing Wireless Water Level Monitoring IoT Device for Smart City

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1936
Author(s):  
Tsun-Kuang Chi ◽  
Hsiao-Chi Chen ◽  
Shih-Lun Chen ◽  
Patricia Angela R. Abu
Keyword(s):  
Power Consumption ◽  
Water Level ◽  
Smart City ◽  
High Accuracy ◽  
Control Device ◽  
Power Efficient ◽  
Sensor Module ◽  
Monitoring Applications ◽  
Level Monitoring ◽  
Water Level Monitoring

In this paper, a novel self-optimizing water level monitoring methodology is proposed for smart city applications. Considering system maintenance, the efficiency of power consumption and accuracy will be important for Internet of Things (IoT) devices and systems. A multi-step measurement mechanism and power self-charging process are proposed in this study for improving the efficiency of a device for water level monitoring applications. The proposed methodology improved accuracy by 0.16–0.39% by moving the sensor to estimate the distance relative to different locations. Additional power is generated by executing a multi-step measurement while the power self-optimizing process used dynamically adjusts the settings to balance the current of charging and discharging. The battery level can efficiently go over 50% in a stable charging simulation. These methodologies were successfully implemented using an embedded control device, an ultrasonic sensor module, a LORA transmission module, and a stepper motor. According to the experimental results, the proposed multi-step methodology has the benefits of high accuracy and efficient power consumption for water level monitoring applications.

scholarly journals Design of Water Level Monitoring using Ultrasonic Sensor

2021 ◽  
Vol 1772 (1) ◽  
pp. 012001
Author(s):  
Hedy Aditya Baskhara ◽  
Saipul Anwar ◽  
Abdurahman
Keyword(s):  
Water Level ◽  
Ultrasonic Sensor ◽  
Level Monitoring ◽  
Water Level Monitoring
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