A Multiscale Soil Moisture and Freeze–Thaw Monitoring Network on the Third Pole

Abstract

SCIENTIFIC BACKGROUND AND OBJECTIVES. As the highest plateau in the world, the Tibetan Plateau (TP) directly impacts its surrounding climate and environment through atmospheric and hydrological processes. Meanwhile, the TP climate changed significantly (such as rapid warming, moistening, solar dimming, and wind stilling) over the past 30 years , which further altered its environment (e.g., glacier retreat, lake expansion, and permafrost degradation, etc.) and brought environmental risks and disasters to the plateau's surrounding regions. The "third pole" was proposed as a geographic element to cover the TP and its adjacent mountains (Qiu 2008), and the "Third Pole Environment" (TPE) was then launched as an international program in 2009, with intension to pool international efforts to reveal and quantify the "water-ice-air-ecosystem-human" interactions in this region (Yao et al. 2012). Among the multisphere interactions on the TP, soil moisture (SM) plays a fundamental role in controlling land surface energy partition, adjusting surface runoff and soil drainage, regulating canopy transpiration and carbon AFFILIATIONS: yang, Qin, y. Chen, anD Tang-key laboratory of tibetan environment changes and land surface Processes, institute of tibetan Plateau research, chinese Academy of sciences, Beijing, china; Zhao, han, LaZhu, Ding, Wu, anD Lin-key laboratory of tibetan environment changes and land surface Processes, institute of tibetan Plateau research, chinese Academy of sciences, and university of chinese Academy of sciences, Beijing, china; Z. Chencollege of global change and earth system science, Beijing normal university, Beijing, china; Lv-state key laboratory of resources and environmental information system, institute of geographic sciences and natural resources research, chinese Academy of sciences, Beijing, china CORRESPONDING AUTHOR: kun Yang, institute of tibetan Plateau research, chinese Academy of sciences, Bldg. 3, courtyard 16, lincui rd., chaoyang district,

Monitoring of Evapotranspiration in a Semi-Arid Inland River Basin by Combining Microwave and Optical Remote Sensing Observations

“…On one hand the AMSR-E soil moisture with rather coarse spatial resolution is a mixing contribution from different land surface elements, which may have smoothed out the spatial variability in land surface soil moisture. On the other hand, other studies have revealed that the AMSR-E soil moisture product exhibits underestimates [73,74]. The MOD16 ETa is overestimated in winter, whereas in the growing season, it is much lower than EC observations at these three sites, especially at the Yingke Oasis station (Figure 5a).…”

“…(2) The soil moisture data derived from passive microwave sensors, such as AMSR-E, Soil Moisture and Ocean Salinity (SMOS), and Fengyun-3 (FY-3) MicroWave Radiation Imager (MWRI) have a coarse spatial resolution (25 km), which is not sufficient for regional scale studies [73,74]. The accuracy and spatial resolution will improve in the near future [81,82].…”

Changes in the timing and duration of the near-surface soil freeze/thaw status from 1956 to 2006 across China

“…NASA is launching the Hydrosphere State Mission as part of the Earth System Science Pathfinder Program (ESSP) to improve satellite monitoring of global land freeze/thaw status and soil moisture (Entekhabi et al, 2004). In China, a multi-scale monitoring network has been established on the Qinghai-Tibetan Plateau (Yang et al, 2013). Fifty-six stations have been installed in cold and high-elevation regions to enhance monitoring of soil temperature and moisture and hence to support remote sensing data and large-scale climate modeling (Su et al, 2011;Yang et al, 2013).…”

“…In China, a multi-scale monitoring network has been established on the Qinghai-Tibetan Plateau (Yang et al, 2013). Fifty-six stations have been installed in cold and high-elevation regions to enhance monitoring of soil temperature and moisture and hence to support remote sensing data and large-scale climate modeling (Su et al, 2011;Yang et al, 2013).…”

Improving soil organic carbon parameterization of land surface model for cold regions in the Northeastern Tibetan Plateau, China

“…However, these retrieval methods perform poorly for estimating soil moisture values in cold regions such as the Tibetan Plateau (TP) area (Chen et al, 2013b;Su et al, 2011;Zeng et al, 2015), and only the value of a few centimeters depth can be derived, which is limited for many applications. Ground measurements are the most accurate soil moisture estimates, and huge efforts have been conducted to establish long-term and largescale soil moisture observation networks in several regions of the world (Dorigo et al, 2011;Yang et al, 2013). Nevertheless, it is still limited and far from sufficient in the TP area, because of the high spatiotemporal variability of soil moisture, the high economic cost and difficulties in practice.…”