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Purpose of Observation:

The soil moisture and soil temperature networks are setup for two primary purposes:

understanding physical process (e.g. facilitating the development of physics-based LSMs)
validating remote sensing products (e.g. facilitating the development of remote sensing retrieval algorithms)

The Tibet-Obs networks were primarily designed to serve both aims. The building up of Tibet-Obs started from 2006 at Naqu, while it was only completed after 2010. Before May 2008, only the Naqu network was equipped with five observation stations. After that, 20 more stations were installed in the Maqu network. It was not until August 2010 both Ali and Shiquanhe networks were equipped with an extra 20 stations, which leads to the Tibet-Obs crossing over three different typical climate conditions over the Tibetan Plateau (Su et al. 2011).

The Tibet-Obs was envisioned to be maintained and operated for providing long-term consistent soil moisture soil temperature climate data records over the TP. Such vision requires the adherence to guidelines/principles for climate monitoring, which includes the site selection(e.g characteristics), International System of Unites (SI) traceability (e.g. instruments), maintenance, data ingest, quality assurance/quality control (QA/QC), and timely delivery of the data.

The long-term consistent SMST climate data records over the TP will inevitably promote fundamental contributions to the understanding of land-atmosphere interaction over the TP, as well as the understanding of physical mechanisms involved in the high-latitude/high-mountain land surface processes that are most sensitive to climate changes).

Other than the compliance of each single SMST station with climate monitoring principles, for the validation of satellite soil moisture products, there is a specific requirement on the number of sites located in one pixel. For example, SMAP specified that a 36-km CVS should have at least 8 stations (70% confidence for 0.03 m3/m3 soil moisture uncertainty with 0.07 m3/m3 variability), a 9-km core site at least 5 stations (70% confidence for 0.03 m3/m3 soil moisture uncertainty with 0.05 m3/m3 variability), and a 3-km core site at least 3 stations (70% confidence for 0.05 m3/m3 soil moisture uncertainty with 0.05 m3/m3 variability). There are similar requirements for SMOS, AMSRE and ESA CCI products.

Participation in (Inter)National Programme/Campaigns:

Third Pole Environment
SMOS/SMAP CalVal Core-Site

Collaboration:

European Space Agency, Paris, France
European Centre for Medium-range Weather Forecast, Reading, United Kingdom
CESBIO, Center for the Study of the Biosphere from Space, Toulouse, France
National Aeronautics and Space Administration, Washington D.C., United States of America
National Center for Atmospheric Research, Boulder, United States of America
Institute of Tibetan Plateau Research, Beijing, Chinese Academy of Science

Externally Funded Projects:

CEOP-AGIS (EU-FP7)
CORE-CLIMAX (EU-FP7)
SMAP Freeze/Thaw (The Netherlands-NWO)
Dragon Advanced Training courses I, II, II and IV (EU-ESA)

Major Scientific Achievements:

The major achievements reached by using data collected at the Tibetan Plateau Earth Observation site are provided in the publication of several PhD dissertations, MSc theses and peer reviewed articles.

PhD Dissertations:

Dr. Rogier van der Velde
van der Velde, R. (2010). Soil moisture remote sensing using active microwaves and land surface modeling. PhD dissertation, Enschede: University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC).
-Dr. Laura Dente
Dente, L. (2016). Microwave remote sensing for soil moisture monitoring : synergy of active and passive observations and validation of retrieved products. PhD dissertation, Enschede: University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC). https://doi.org/10.3990/1.9789036541121
Dr. Donghai Zheng
Zheng, D. (2015). Water and heat exchanges on the Tibetan Plateau: observation and modeling of the yellow river source region. PhD dissertation, Enschede: University of Twente. https://doi.org/10.3990/1.9789036539883
Dr. Qiang Wang
Wang, Q. (2018). Soil moisture estimation by synergetic use of Aquarius active and passive I-band microwave observations. PhD dissertation, Enschede: University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC).
Dr. Shaoning Lv
Lv, S. (2019). Soil effective temperature and its application in passive remote sensing of soil moisture at L-band. PhD dissertation, Enschede: University of Twente, Faculty of Geo-Information Science and Earth Observation (ITC).

Ongoing:

PhD Candidate Hong Zhao :Soil Hydraulic and Thermal Properties Estimated from Remote Sensing
PhD Candidate Lianyu Yu: Investigating Freeze/Thaw Process of Permafrost over Tibetan Plateau under Climate Change
PhD Candidate Mengna Li: Retrieving Aquifer Parameters from Satellite Measurements and In-situ Measurements

MSc Theses:

Amos Tabalia: (2016) Evaluation of l-band brightness temperature products using cmem modelled in-situ observations and SMAP brightness temperature;
Hongyi Chen: (2016) Numerical analysis of freeze-thaw processes over seasonal frozen grounds: a case study over maqu, Tibetan Plateau;
Jinbang Peng: (2017) Application of cosmic-ray probe for the detection of freezing-thawing process over Tibetan Plateau;
Jiaqi Yang: (2017) Automated quality control of in situ soil moisture and soil temperature data from the Tibet-Obs networks; (MSc CumLaude)
Ruodan Zhuang: (2018) Quantifying Land Surface and Subsurface Soil Moisture over Tibetan Plateau; (granted with ITC Excellence Programme)
Samuel Mwangi: (2019) Assimilation of CRP Measurements for the Detection of Freezing-Thawing Process using the STEMMUS Model at Maqu Site, Tibetan Plateau; (granted with ITC Excellence Programme, MSc CumLaude)

Publications:

Wang, Q., van der Velde, R., Ferrazzoli, P., Chen, X., Bai, X., & Su, Z. (2019). Mapping soil moisture across the Tibetan Plateau plains using Aquarius active and passive L-band microwave observations. International Journal of Applied Earth Observation and Geoinformation, 77, 108-118. https://doi.org/10.1016/j.jag.2019.01.005
Bai, X., Zeng, J., Chen, K. S., Li, Z., Zeng, Y., Wen, J., ... Su, Z. (2019). Parameter Optimization of a Discrete Scattering Model by Integration of Global Sensitivity Analysis Using SMAP Active and Passive Observations. IEEE transactions on geoscience and remote sensing, 57(2), 1084-1099. [8457483]. https://doi.org/10.1109/TGRS.2018.2864689
Wang, Q., Van Der Velde, R., & Su, Z. (2018). Use of a discrete electromagnetic model for simulating Aquarius L-band active/passive observations and soil moisture retrieval. Remote sensing of environment, 205, 434-452. https://doi.org/10.1016/j.rse.2017.10.044
Dente, L., Ferrazzoli, P., Su, Z., van der Velde, R., & Guerriero, L. (2014). Combined use of active and passive microwave satellite data to constrain a discrete scattering model. Remote sensing of environment, 155, 222-238. https://doi.org/10.1016/j.rse.2014.08.031
Zheng, D., Li, X., Wang, X., Wang, Z., Wen, J., van der Velde, R., ... Su, Z. (2019). Sampling depth of L-band radiometer measurements of soil moisture and freeze-thaw dynamics on the Tibetan Plateau. Remote sensing of environment, 226, 16-25. https://doi.org/10.1016/j.rse.2019.03.029
Zheng, D., van der Velde, R., Su, Z., Wen, J., Wang, X., & Yang, K. (2018). Impact of soil freeze-thaw mechanism on the runoff dynamics of two Tibetan rivers. Journal of hydrology, 563, 382-394. https://doi.org/10.1016/j.jhydrol.2018.06.024
Zheng, D., van der Velde, R., Su, Z., & Zeng, Y. (2017). L-Band Microwave Emission of Soil Freeze-Thaw Process in the Third Pole Environment. IEEE transactions on geoscience and remote sensing, 55(9), 5324-5338. https://doi.org/10.1109/TGRS.2017.2705248
Zhao, H., Zeng, Y., Lv, S., & Su, Z. (2018). Analysis of soil hydraulic and thermal properties for land surface modeling over the Tibetan Plateau. Earth system science data, 10(2), 1031-1061. https://doi.org/10.5194/essd-10-1031-2018
Yu, L., Zeng, Y., Wen, J., & Su, Z. (2018). Liquid-Vapor-Air Flow in the Frozen Soil. Journal of geophysical research : Atmospheres, 123(14), 7393-7415. https://doi.org/10.1029/2018JD028502
Zheng, D., van der Velde, R., Su, Z., Wen, J., & Wang, X. (2017). Assessment of Noah land surface model with various runoff parameterizations over a Tibetan river. Journal of geophysical research : Atmospheres, 122(3), 1488-1504. https://doi.org/10.1002/2016JD025572
Zheng, D., Van Der Velde, R., Su, B., Wen, J., Wang, X., & Yang, K. (2017). Evaluation of Noah Frozen Soil Parameterization for Application to a Tibetan Meadow Ecosystem. Journal of hydrometeorology, 18(6), 1749-1763. https://doi.org/10.1175/JHM-D-16-0199.1
Zheng, D., van der Velde, R., Su, Z., Wen, J., Wang, X., Booij, M. J., ... Ek, M. B. (2016). Impacts of Noah model physics on catchment-scale runoff simulations. Journal of geophysical research : Atmospheres, 121(2), 807-832. https://doi.org/10.1002/2015JD023695
Zheng, D., van der Velde, R., Su, Z., Wang, X., Wen, J., Booij, M. J., ... Chen, Y. (2015). Augmentations to the Noah model physics for application to the Yellow River source area. Part I: Soil water flow. Journal of hydrometeorology, 16(6), 2659-2676. https://doi.org/10.1175/JHM-D-14-0198.1
Zheng, D., van der Velde, R., Su, Z., Wang, X., Wen, J., Booij, M. J., ... Chen, Y. (2015). Augmentations to the Noah model physics for application to the Yellow River source area. Part II: Turbulent heat fluxes and soil heat transport. Journal of hydrometeorology, 16(6), 2677-2694. https://doi.org/10.1175/JHM-D-14-0199.1
Zheng, D., van der Velde, R., Su, Z., Wen, J., Booij, M. J., Hoekstra, A. Y., & Wang, X. (2015). Under-canopy turbulence and root water uptake of a Tibetan meadow ecosystem modeled by Noah-MP. Water resources research, 51(7), 5735-5755. https://doi.org/10.1002/2015WR017115
Zheng, D., van der Velde, R., Su, Z., Booij, M. J., Hoekstra, A. Y., & Wen, J. (2014). Assessment of roughness length schemes implemented within the Noah land surface model for high-altitude regions. Journal of hydrometeorology, 15(3), 921-937. https://doi.org/10.1175/JHM-D-13-0102.1
Su, Z., de Rosnay, P., Wen, J., Wang, L., & Zeng, Y. (2013). Evaluation of ECMWF's soil moisture analyses using observations on the Tibetan Plateau. Journal of geophysical research : Atmospheres, 118(11), 5304-5318. https://doi.org/10.1002/jgrd.50468
Hofste, J. G., van der Velde, R., Wang, X., Zheng, D., Wen, J., van der Tol, C., & Su, Z. (2018). Broadband Full Polarimetric Scatterometry for Monitoring Soil Moisture and Vegetation Properties Over a Tibetan Meadow. In IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium (pp. 2007-2010). IEEE. https://doi.org/10.1109/IGARSS.2018.8519380
Lv, S., Y. Zeng, Z. Su and J. Wen, "A Closed-Form Expression of Soil Temperature Sensing Depth at L-Band," in IEEE Transactions on Geoscience and Remote Sensing. doi: 10.1109/TGRS.2019.2893687
Lv, S., Zeng, Y., Wen, J., Zhao, H., & Su, Z. (2018). Estimation of Penetration Depth from Soil Effective Temperature in Microwave Radiometry. Remote sensing, 10(4), 1-19. [519]. https://doi.org/10.3390/rs10040519
Lv, S., Zeng, Y., Wen, J., & Su, Z. (2016). A reappraisal of global soil effective temperature schemes. Remote sensing of environment, 183, 144-153. https://doi.org/10.1016/j.rse.2016.05.012
Lv, S., Zeng, Y., Wen, J., Zheng, D., & Su, Z. (2016). Determination of the optimal mounting depth for calculating effective soil temperature at L-band : Maqu case. Remote sensing, 8(6), -. [476]. https://doi.org/10.3390/rs8060476
Lv, S., Wen, J., Zeng, Y., Tian, H., & Su, Z. (2014). An improved two-layer algorithm for estimating effective soil temperature in microwave radiometry using in situ temperature and soil moisture measurements. Remote sensing of environment, 152, 356-363. https://doi.org/10.1016/j.rse.2014.07.007
Colliander, A., Jackson, T. J., Chan, S. K., O'Neill, P., Bindlish, R., Cosh, M. H., ... Yueh, S. H. (2018). An assessment of the differences between spatial resolution and grid size for the SMAP enhanced soil moisture product over homogeneous sites. Remote sensing of environment, 207, 65-70. https://doi.org/10.1016/j.rse.2018.02.006
Zheng, D., van der Velde, R., Wen, J., Wang, X., Ferrazzoli, P., Schwank, M., ... Su, Z. (2018). Assessment of the SMAP Soil Emission Model and Soil Moisture Retrieval Algorithms for a Tibetan Desert Ecosystem. IEEE transactions on geoscience and remote sensing, 56(7), 3786-3799. https://doi.org/10.1109/TGRS.2018.2811318
Rahmati, M., Weihermüller, L., Vanderborght, J., Pachepsky, Y. A., Mao, L., Sadeghi, S. H., ... Zhao, H. (2018). Development and analysis of the Soil Water Infiltration Global database. Earth system science data, 10(3), 1237-1263. https://doi.org/10.5194/essd-10-1237-2018
Bindlish, R., Jackson, T. J., Cosh, M., Koike, T., Fuiji, X., de Jeu, R., ... Walker, J. (2017). AMSR2 Soil Moisture Product Validation. In 2017 IEEE International Geoscience and Remote Sensing Symposium; 37th; 23-28 Jul. 2017; Fort Worth, TX; United States NASA, Goddard Space Flight Center.
Reichle, R. H., De Lannoy, G. J. M., Liu, Q., Ardizzone, J. V., Colliander, A., Conaty, A., ... Zeng, Y. (2017). Assessment of the SMAP Level-4 Surface and Root-Zone Soil Moisture Product Using In Situ Measurements. Journal of hydrometeorology, 18(10), 2621-2645. https://doi.org/10.1175/JHM-D-17-0063.1
O'Neill, P., Chan, S., Bindlish, R., Jackson, T., Chaubell, J., Piepmeijer, J., ... Kerr, Y. H. (2017). Assessment of Version 4 of the SMAP Passive Soil Moisture. In Proceedings of 2017 IEEE International Geoscience and Remote Sensing Symposium; 37th; 23-28 Jul. 2017 NASA, Goddard Space Flight Center.
Chan, S., Bindlish, R., O'neill, P. E., Jackson, T., Chaubell, J., Piepmeijer, J., ... Kerr, Y. H. (2017). Development and Validation of The SMAP Enhanced Passive Soil Moisture Product : open access. In Proceedings of the IEEE International Geoscience and Remote Sensing Symposium 2017; 37th; 23-28 Jul. 2017; Fort Worth, TX; United States Greenbelt: NASA, Goddard Space Flight Center.
Colliander, A., Jackson, T. J., Bindlish, R., Chan, S., Das, N., Kim, S. B., ... Yueh, S. (2017). Validation of SMAP surface soil moisture products with core validation sites. Remote sensing of environment, 191, 215-231. https://doi.org/10.1016/j.rse.2017.01.021
Bai, X., He, B., Li, X., Zeng, J., Wang, X., Wang, Z., ... Su, Z. (2017). First Assessment of Sentinel-1A Data for Surface Soil Moisture Estimations Using a Coupled Water Cloud Model and Advanced Integral Equation Model over the Tibetan Plateau. Remote sensing, 9(7), [714]. https://doi.org/10.3390/rs9070714
Wang, Q., van der Velde, R., Su, Z., & Wen, J. (2016). Aquarius L-band scatterometer and radiometer observations over a Tibetan Plateau site. International Journal of Applied Earth Observation and Geoinformation (JAG), 45(B), 165-177. https://doi.org/10.1016/j.jag.2015.06.010
Bindlish, R., Jackson, T. J., Cosh, M., Milak, S., Njoku, E., Chan, S., ... Martinez, J. (2016). Development and validation of the GCOM-W AMSR2 soil moisture product. In Proceedings of International Geoscience and Remote Sensing Symposium (IGARSS) : Advancing the understanding of our living planet, 10-15 July 2016, Beijing, China (pp. 1647-1650). (IGARSS; No. 2016). IEEE. https://doi.org/10.1109/IGARSS.2016.7729421
van der Velde, R., Salama, M. S., Pellarin, T., Ofwono, M., Ma, Y., & Su, Z. (2014). Long term soil moisture mapping over the Tibetan Plateau using Special Sensor Microwave/Imager. Hydrology and earth system sciences, 18(4), 1323-1337. https://doi.org/10.5194/hess-18-1323-2014
van der Velde, R., Su, Z., & Wen, J. (2014). Roughness determination from multi - angular ASAR Wide Swath mode observations for soil moisture retrieval over the Tibetan Plateau. In Proceedings of EUSAR 2014 : 10th European conference on synthetic aperture radar, 3-5 June 2014, Berlin, Germany (pp. 163-165). Berlin: VDE Verlag.
Zheng, D., Wang, X., Van Der Velde, R., Ferrazzoli, P., Wen, J., Wang, Z., ... Su, Z. (2018). Impact of surface roughness, vegetation opacity and soil permittivity on L-band microwave emission and soil moisture retrieval in the third pole environment. Remote sensing of environment, 209, 633-647. https://doi.org/10.1016/j.rse.2018.03.011
Zeng, Y., Su, Z., van der Velde, R., Wang, L., Xu, K., Wang, X., & Wen, J. (2016). Blending satellite observed, model simulated, and in situ measured soil moisture over Tibetan Plateau. Remote sensing, 8(3), -. [268]. https://doi.org/10.3390/rs8030268
van der Velde, R., Salama, M. S., van Helvoirt, M., & Su, Z. (2012). Decomposition of uncertainties between coarse MM5 - Noah - Simulated and fine ASAR - retrieved soil moisture over Central Tibet. Journal of hydrometeorology, 13(6), 1925-1938. https://doi.org/10.1175/JHM-D-11-0133.1
van der Velde, R., & Su, Z. (2009). Dynamics in land - surface conditions on the Tibetan Plateau observed by advanced synthetic aperture radar, ASAR. Hydrological sciences journal, 54(6), 1079-1093. https://doi.org/10.1623/hysj.54.6.1079
Dente, L., Vekerdy, Z., de Jeu, R., & Su, Z. (2013). Seasonality and autocorrelation of satellite - derived soil moisture products. International journal of remote sensing, 34(9-10), 3231-3247. https://doi.org/10.1080/01431161.2012.716923
Dente, L., Vekerdy, Z., Wen, J., & Su, Z. (2012). Maqu network for validation of satellite - derived soil moisture products. International Journal of Applied Earth Observation and Geoinformation (JAG), 17, 55-65. https://doi.org/10.1016/j.jag.2011.11.004
van der Velde, R., Su, Z., van Oevelen, P., Wen, J., Ma, Y., & Salama, M. S. (2012). Soil moisture mapping over the central part of the Tibetan Plateau using a series of ASAR WS images. Remote sensing of environment, 120, 175-187. https://doi.org/10.1016/j.rse.2011.05.029
Dente, L., Su, Z., & Wen, J. (2012). Validation of SMOS soil moisture products over the Maqu and Twente regions. Sensors (Switserland), 12(8), 9965-9986. https://doi.org/10.3390/s120809965
Su, Z., Wen, J., Dente, L., van der Velde, R., Wang, Y., Ma, K., & Hu, Z. (2011). The Tibetan plateau observatory of plateau scale soil moisture and soil temperature, Tibet - Obs, for quantifying uncertainties in coarse resolution satellite and model products. Hydrology and earth system sciences, 15(7), 2303-2316. https://doi.org/10.5194/hess-15-2303-2011
van der Velde, R., Su, Z., Ek, M., Rodell, M., & Ma, Y. (2009). Influence of thermodynamic soil and vegetation parameterizations on the simulation of soil temperature states and surface fluxes by the Noah LSM over a Tibetan plateau site. Hydrology and earth system sciences (HESS) : open access, 13(1), 759-777.
van der Velde, R., Su, Z., & Ma, Y. (2008). Impact of soil moisture dynamics on ASAR sigma degrees signatures and its spatial variability observed over the Tibetan plateau. Sensors (Switserland), 8(9), 5479-5491. https://doi.org/10.3390/s8095479

Tibetan Plateau, Peoples Republic of China