Mr. Xiaoji Shen
Mr. Xiaoji Shen
Dr. Xiaoji Shen is a Research Professor at Tongji University, China. Dr. Xiaoji Shen has made seminal contributions to demonstrating a new state-of-the-art satellite concept that will provide global root-zone moisture information using microwave observations at P-band (lower than 1 GHz), which is a prominent advancement over the less than 5 cm near-surface moisture sensed by existing satellites. His work has led to a number papers published in prestigious journals and gained great interest from NASA and ESA in incorporating his research into the next-generation satellite. His current research interests focus on remote sensing and modelling of the carbon-water cycle in terrestrial ecosystems.
Research Interests
Research Projects
Current projects
P-band microwave radiometry and soil moisture retrieval
Soil moisture is an excellent indicator of climate change. Moreover, it controls various processes in the water, energy, and carbon exchanges between the atmosphere and the land surface. However, soil moisture products derived from passive microwave remote sensing are limited to a relatively shallow moisture retrieval depth, which is commonly held to be within the top 5 cm at L-band (~21 cm wavelength / 1.4 GHz). Moreover, the soil moisture retrieval at L-band is also complicated and degraded by the soil surface roughness and vegetation canopy. It has been reported that longer wavelengths are expected to have not only a greater moisture retrieval depth but also reduced impacts of soil surface roughness and vegetation, which has not yet been verified at P-band (~40 cm wavelength / 0.75 GHz). Consequently, this research aims at demonstrating these potential benefits brought from the longer wavelength of P-band. Ultimately, the P-band Microwave Emission of the Biosphere (P-MEB) model will be developed using extensive tower-based data and tested on independent airborne-based data over a range of soil roughness and vegetation conditions. This will ultimately lead to preparedness for the next generation of soil moisture satellite missions. This research is organized around four key questions:
1. Does P-band have a greater moisture retrieval depth than L-band?
2. Is P-band less impacted by soil surface roughness than L-band?
3. Is P-band less impacted by vegetation effects than L-band?
4. Is P-band able to provide more accurate soil moisture maps than L-band?
| Evaluation of Tau-Omega Model over Bare and Wheat-Covered Flat and Periodic Soil Surfaces at P- and L-band
Shen, X., Walker, J.P., Ye, N., Wu, X., Brakhasi, F., Boopathi, N., Zhu, L., Yeo, I.-Y., Kim, E., Kerr, Y., & Jackson, T. Remote Sensing of Environment, under review |
2022 |
| Impact of random and periodic surface roughness on P- and L-band radiometry
Shen, X., Walker, J.P., Ye, N., Wu, X., Brakhasi, F., Boopathi, N., Zhu, L., Yeo, I.-Y., Kim, E., Kerr, Y., & Jackson, T. Remote Sensing of Environment 269, 112825 |
2022 |
| Soil moisture retrieval depth of P-and L-band radiometry: predictions and observations
Shen, X., Walker, J.P., Ye, N., Wu, X., Boopathi, N., Yeo, I.-Y., Zhang, L., & Zhu, L. IEEE Transactions on Geoscience and Remote Sensing, 59, 6814-6822 |
2021 |
| Stochastic ensemble methods for multi-SAR-mission soil moisture retrieval
Zhu, L., Walker, J.P., & Shen, X. Remote Sensing of Environment, 251, 112099 |
2020 |
| Vegetation changes in the Three-river headwaters region of the Tibetan Plateau of China
Shen, X., An, R., Feng, L., Ye, N., Zhu, L., & Li, M. Ecological Indicators 93, 804-812 |
2018 |
| Evaluation of the European Space Agency climate change initiative soil moisture product over China using variance reduction factor
Shen, X., An, R., Quaye‐Ballard, J.A., Zhang, L., & Wang, Z. JAWRA Journal of the American Water Resources Association 52 (6), 1524-1535 |
2016 |
| Validation of the ESA CCI soil moisture product in China
An, R., Zhang, L., Wang, Z., Quaye-Ballard, J.A., You, J., Shen, X., Gao, W., Huang, L., Zhao, Y., & Ke, Z. International journal of applied earth observation and geoinformation 48, 28-36 |
2016 |