This data set contains the daily values of water temperature and water level change in Ranwu Lake in Tibet from May 15, 2009, to December 31, 2016. Observation instrument model: an automatic HOBO water level and temperature logger U20-001-01; acquisition time: 30 minutes. The data were collected automatically. The observations and data collection were performed in strict accordance with the instrument operating specifications, and the data have been published in relevant academic journals. Data with obvious errors were removed, and the missing data were replaced by null values. Data collection location: Ranwu Lake, southeast Tibet Middle lake outlet: longitude: 96°46'16"; latitude: 29°29'28"; elevation: 3928 m. Lower Lake outlet: longitude: 96°38'52"; latitude: 29°28'52"; elevation: 3923 m. Laigu upper Lake: longitude: 94°49'49"; latitude: 29°18'07"; elevation: 4025 m. This data contains fileds as follows: Field 1: Site Number Data type: Alphanumeric characters (50) Field 2: Time Data type: Date type Field 3: Water temperature, °C Data type: Double-precision floating-point format Field 4: Relative water level, cm Data type: Double-precision floating-point format
The long-term evolution of lakes on the Tibetan Plateau (TP) could be observed from Landsat series of satellite data since the 1970s. However, the seasonal cycles of lakes on the TP have received little attention due to high cloud contamination of the commonly-used optical images. In this study, for the first time, the seasonal cycle of lakes on the TP were detected using Sentinel-1 Synthetic Aperture Radar (SAR) data with a high repeat cycle. A total of approximately 6000 Level-1 scenes were obtained that covered all large lakes (> 50 km2) in the study area. The images were extracted from stripmap (SM) and interferometric wide swath (IW) modes that had a pixel spacing of 40 m in the range and azimuth directions. The lake boundaries extracted from Sentinel-1 data using the algorithm developed in this study were in good agreement with in-situ measurements of lake shoreline, lake outlines delineated from the corresponding Landsat images in 2015 and lake levels for Qinghai Lake. Upon analysis, it was found that the seasonal cycles of lakes exhibited drastically different patterns across the TP. For example, large size lakes (> 100 km2) reached their peaks in August−September while lakes with areas of 50−100 km2 reached their peaks in early June−July. The peaks of seasonal cycles for endorheic lakes were more pronounced than those for exorheic lakes with flat peaks, and glacier-fed lakes with additional supplies of water exhibited delayed peaks in their seasonal cycles relative to those of non-glacier-fed lakes. Large-scale atmospheric circulation systems, such as the westerlies, Indian summer monsoon, transition in between, and East Asian summer monsoon, were also found to affect the seasonal cycles of lakes. The results of this study suggest that Sentinel-1 SAR data are a powerful tool that can be used to fill gaps in intra-annual lake observations.
Lakes on the Tibetan Plateau (TP) are an indicator and sentinel of climatic changes. We extended lake area changes on the TP from 2010 to 2018, and provided a long and dense lake observations between the 1970s and 2018. We found that the number of lakes, with area larger than 1 km2, has increased to ~1400 in 2018 from ~1000 in the 1970s. The total area of these lakes decreased between the 1970s and ~1995, and then showed a robust increase, with the exception of a slight decrease in 2015. This expansion of the lakes on the highest plateau in the world is a response to a hydrological cycle intensified by recent climate changes.
The data set includes the vertical profile of water quality and the multi-parameter data of surface water quality of Selincho Lake during the investigation of the sources of rivers and lakes from June to July of 2017. The main water quality parameters measured are dissolved oxygen, conductivity, pH, water temperature, etc. YSI EXO2 water quality multi-parameter measuring instrument is calibrated according to lake surface elevation and local pressure before each measurement. The time interval of measurement is set at 0.25s, and the speed of putting in is slow, so he high continuity of data acquisition is guaranteed. The original data obtained include the measured data exposed to air above the water surface, which are eliminated in the later processing.
This is the water level observation data of Selincuo Lake. It can be used in Climatology, Environmental Change, Hydrologic Process in Cold Regions and other disciplinary areas. The data is observed from September 17, 2016 to February 15,2017. It is measured by automatic water gauge and a piece of data is recorded every 60 minutes. The data includes the water pressure and water temperature of the water level observation point on the east bank of Selincuo Lake.The original data is precise, with the pressure accurate to 0.001kP and the water temperature 0.001℃. The original data forms a continuous time series after quality control. And the daily mean index data is obtained through calculation. The data is stored as an excel file.
This data set includes the water depth measurement data during the Jianghuyuan expedition from June to July 2017 over the Kering Tso Lake. The measurement time is on July 2, 2017. The data was measured by Lowrance HDS-5 sonar sounder. The original data was generated by surfer 13 software and Kriging difference method. The original data contained more invalid depth data, which had been screened out in the later stage of collation. The survey line is reasonable to ensure that the data cover all depth gradients.
This data set comprises the depth measurements of Co Ngoin Lake during the River and Lake Source Investigation from June to July in 2017. The measurements were obtained on June 24, 2017 using a Lowrance HDS-5 sonar depth finder. The original data are made into the isobath map processed by the Surfer 13 software using the Kriging method. The original measured data contain numerous invalid depth data, all of which has been eliminated in the postselection process. The selected measurement line is reasonable, and the data cover various depth gradients.
This data set is the hydrogen and oxygen isotope ratio data of water samples collected in the Selincuo, Gayringco, and Co Ngoin Lake during the Water Source Study in 2017. The water sample collection time is from June 2017 to July 2017. It can be used in Lake Water Cycle, Lake Environmental Changes, Study of Isotopic Geochemistry and other disciplinary areas.
These are the water quality vertical slope data of Co Ngoin Lake obtained during the River and Lake Source Investigation from June to July in 2017. The main water quality observation data include dissolved oxygen, electrical conductivity, PH, water temperature and others.
This is the water quality data at depth of 2m, 15m, 18m, 28m, and 38m observed in Selincuo Lake from June to July, 2017. The data can be used in many fields, such as the physical and chemical properties of lakes and their climate response and lake environment changes.