Based on our observation data and other data, the past runoff trends of mountain cryosphere in China and future trend by CBHM was documented. In the past 50 yr, river runoff has generally shown an increasing trend as a result of increased rainfall, snowfall, and glacial runoff in the cold regions of western China. Because the total glacier decreased by ~18% in area and 28% in volume in western China, Permafrost degradation has mainly increased infiltration and enlarged the groundwater reservoir. This could lead to an increased winter flow in western China. Although the extent of snow cover has decreased slightly over the past 50 yr, snowmelt has shown an increasing trend in most watersheds in the cold regions of western China as a result of the increased snowfall. Along with increasing air temperature, glacial runoff will decrease in the near future, and the rate of this decrease is inversely proportional to the glacial size. According to different receptive concentration pathway (RCP) scenarios, glacial runoff will decrease 60 to 70% and 80 to 90%, compared with their average values in the southern and southeastern Tibet Plateau and western Qilian Mountains, respectively, between 1971 and 2010 under RCP2.6 and RCP 4.5 by the 2090s. Most of the small glaciers will have disappeared, leading to glacial runoff started to decrease.
Serving as a subwatershed of the Heihe watershed allied telemetry experimental research), the Hulu catchment (38°12´–38°17´ N, 99°50´–99°54´ E) is located in the upper reaches of Hei River in the central part of the Qilian Mountains. and it represents a pristine alpine catchment with rugged terrain and little human disturbance on the southeastern region of the Qilian Mountains.Two minor tributaries are sourced from glacier and moraine–talus zones and then merge at the catchment outlet. The elevation fluctuates from 2960 to 4820 m asl, with a span of 1860 m, and it gradually increases from north to south. The slope ranges from 0 to 85°. Because the vertical landscape exhibits obvious spatial differentiation, the catchment was chosen to study the integrated research and observation experiments of hydrological processes in a mountain cryospheric region.
To apply hydrological models in the alpine catchment, we have obtained long-term continuous soil parameter data in the soil pit synchronously with those collected at AWS. Two soil heat flux plates (HFP01SC) (Hukseflux Thermal Sensors) were used to measure soil heat flux at depths of 7, 12, and 17 cm. A set of moisture probes (Sentek Sensor Technologies, Inc.) was placed in soil to measure soil moisture at depths of 10, 20, 30, 40, 50, 60, 80, and 100 cm. A set of 109SS-L probes (Campbell Scientific, Inc.) was installed in soil to measure soil temperature at depths of 20, 40, 60, 80, 100, 120, 160, and 200 cm. An SI-111 infrared radiometer (Apogee Instr. Inc.) was used to measure the LST.
There are three ways to observe evapotranspiration in the CHOICE: automatic and manual weighing minilysimeters and eddy covariance (EC) systems. During the early stage of the CHOICE, evapotranspiration was measured with two manual weighing microlysimeters, which were 40 cm in depth and 31.5 cm in diameter and were installed in the SMF at the Hulu-1 field on 1 July 2009 with an electronic scale of 2 g (0.026 mm) in precision. With the development of the CHOICE, five automatic microlysimeters (CHOICE-LYS40, T&D) were arranged in the same field as the AWS of the Hulu-1 to Hulu-5 field in August 2013. The observation time and interval followed those of the AWS, with a balance of 1 g (0.01 mm) in precision. And an EC150 system (Campbell Scientific Inc.) was installed on a lattice mast at 5.8 m at the Hulu-2 field in September 2011.
The data transmission of the CHOICE involves the integrated use of ZigBee network technology and mobile Internet technology for the implementation of the remote transmission of monitoring data. The data center adopts heterogeneous largedata storage and retrieval technology based on middleware, which guarantees thecomprehensive storage and retrieval of all types of field observation elements. This solves the problem of obtaining continuous high-precision acquisition data for monitoring data.
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CSTR:11738.11.NCDC.ZENODO.DB3960.2023
10.5061/dryad.sh6n0tc