080904 Electromagnetics and Microwave Engineering - Radar Remote Sensing

Dr. Yang Lei received the B.Eng. degree (Hons.) in Electrical engineering from Beihang University, Beijing, China, in 2008, and the M.Sc. and Ph.D. (Hons.) degrees in electrical engineering from the University of Massachusetts Amherst, Amherst, MA, USA, in 2010 and 2016, respectively. From 2016 to 2018, he was a NASA Postdoctoral Fellow with the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. From 2018 to 2021, he was a Postdoctoral Scholar from 2018 to 2019 and an Associate Research Scientist from 2019 to 2021 with the Division of Geological and Planetary Sciences, California Institute of Technology. Starting from 2022, he has been employed as a Research Scientist/Professor by the Earth Science Section and Laboratory of Microwave Remote Sensing of the National Space Science Center, Chinese Academy of Sciences. 

Dr. Lei has extensive experience in radar signal processing, development of parameter inversion algorithms, and electromagnetic scattering modeling, in particular, processing, interpreting, and modeling the Interferometric SAR (InSAR) data from spaceborne sensors (e.g. JAXA’s ALOS, ALOS-2, ESA’s Sentinel-1, and DLR’s TanDEM-X). His research interests include advanced radar remote-sensing techniques (such as SAR, InSAR, polarimetric InSAR, and SAR tomography) for mapping environmental resources (primarily vegetation, snow, ice, and planetary sub-surface), as well as applied electromagnetics modeling and simulation for the earth and planetary remote-sensing applications. 

Dr. Lei was a recipient of the prestigious NASA Earth and Space Science Fellowship (NESSF) from 2012 to 2015 and the NASA Postdoctoral Program (NPP) from 2016 to 2018 for his primary contribution to forest height and disturbance retrieval using spaceborne InSAR sensors. He participated in multiple international research projects, such as those related to the NISAR and Europa Clipper missions as well as the ITS_LIVE project. He was awarded the NISAR Team Award on tropospheric model down-selection by NASA/JPL. He also serves as the data proposal PI for JAXA’s 3rd Research Announcement on the Earth Observations (EO-RA3) and DLR’s TanDEM-X science proposal. He is the recipient of the Excellent Young Scientists Fund Program from 2022 to 2025 by the National Natural Science Foundation of China. He serves as the Topical Associate Editor of IEEE Transactions of Geoscience and Remote Sensing.

University of Massachusetts, Amherst MA  Ph.D.   Electrical & Computer Engineering 2010-2016    GPA: 4.0

University of Massachusetts, Amherst MA  M.S.    Electrical & Computer Engineering 2008-2010    GPA: 4.0

Beihang University, Beijing, China              B.E.     Electrical & Computer Engineering 2004-2008    GPA: 3.9

02/2022-present                         Research Scientist / Professor

                                                    National Space Science Center, Chinese Academy of Sciences

    Beijing, China

• Lead the newly-founded group on advanced radar remote sensing of natural environment (vegetation, snow and ice) in the Earth Science Section and Laboratory of Microwave Remote Sensing 

02/2019-12/2021                         Associate Research Scientist

Supervisor: Charles Elachi      California Institute of Technology, Pasadena CA

• Developed offset/feature tracking algorithms and Python-based software autonomous Repeat Image Feature Tracking (autoRIFT) for JPL’s InSAR Scientific Computing Environment (ISCE) in the application of mapping global ice motion velocity, and validate using European Space Agency’s (ESA) Sentinel-1/-2, NASA’s Landsat-8 and NASA’s future NISAR data

• Developed Python-based software for tropospheric phase correction of NASA’s NISAR interferometric products, and evaluate the quality of the correction with different weather models 

• Validate the Pseudospectral Time-domain (PSTD) simulator with real planetary radar sounding data (e.g. SHARAD for Mars)

• Developed a new algorithm for simultaneously retrieving forest height and underlying topography using German Aerospace Center’s (DLR) TanDEM-X InSAR data, and validate with airborne lidar and field inventory data over a Brazilian tropical forest

04/2018-01/2019                           Postdoctoral Scholar

Supervisor: Charles Elachi        California Institute of Technology, Pasadena CA

• Developed computational electromagnetics algorithms and radar scattering models for full-wave radar sounding simulations in planetary science applications, e.g. the composition of Europa’s (Jupiter’s moon) icy shell.

• Developed a two-dimensional Pseudospectral Time-domain (PSTD) simulator for large-scale electromagnetic scattering and radar sounding applications

04/2016-04/2018                          NASA Postdoctoral Program (NPP) Fellow

Supervisor: Robert Treuhaft     NASA Jet Propulsion Laboratory, Pasadena CA

• Refined the “single radar satellite technique” for forest height retrieval and the automated Python-based Forest Stand Height (FSH) inversion and mosaicking software, and validated with Japanese Aerospace Exploration Agency’s (JAXA) ALOS-1 and ALOS-2 InSAR data, airborne lidar data and field inventory data over the northeast forest of US

• Developed a new forest disturbance (selective logging) detection approach, and validated with JAXA’s ALOS-1 InSAR data and NASA’s Landsat data over Queensland, Australia

• Developed a new forest change monitoring technique, by combining multi-temporal DLR’s TanDEM-X and JAXA’s ALOS-2 InSAR data, to quantify the status and natural change of forest biomass/height as well as forest disturbance (deforestation, selective logging and fire) for a Brazilian tropical forest, and validated with airborne lidar and field inventory data

• Developed TomoSAR and InSAR/PolInSAR algorithms to image snow vertical structure and measure Snow Water Equivalent (SWE) using JPL’s ground-based multi-frequency full-polarization radar (first U.S. radar for such applications), and engaged in the field work at Fraser, Colorado

• Investigated computational electromagnetics algorithms to simulate full-wave radar scattering from arbitrary dielectric scenes for JPL’s Europa radar sounding project 

09/2015-01/2016                          Senior Research Scientist

Supervisor: Nathan Torbick      Applied GeoSolutions, Newmarket NH

• Developed an automated Python-based Forest Stand Height (FSH) inversion and mosaicking software for the “single radar satellite technique” from PhD work

• Created the first forest height mosaic map for the Northeast US using JAXA’s ALOS-1 InSAR data

03/2015-04/2015                          Visiting student

Supervisor: Robert Treuhaft     NASA Jet Propulsion Laboratory, Pasadena CA

• Worked on electromagnetic InSAR scattering models for snow and vegetation

09/2010-01/2016                          Research assistant, Microwave Remote Sensing Laboratory

Advisor: Paul Siqueira              University of Massachusetts, Amherst MA

• Developed a “single radar satellite technique” (versus the state-of-the-art two radar satellites with $500M cost saving for launching another satellite) for NASA’s next generation radar and lidar satellites, NISAR and GEDI, in large-scale forest height mapping, covering all facets of scattering theory, simulation, data processing, and experimental validation. A forest height mosaic was created for Maine, US for the first time using JAXA’s ALOS-1 InSAR data and a small piece of airborne lidar data as training set. This technique was also verified using electromagnetic scattering simulations by adapting ESA’s PolSARproSim software.

• Developed a new InSAR/PolInSAR technique to measure snow structure (grain size, volume density and depth) as well as SWE.

• Title of dissertation: Electromagnetic Scattering Models for InSAR Correlation Measurements of Vegetation and Snow

• Research Scientist / Professor, Earth Science Section & Laboratory of Microwave Remote Sensing, National Space Science Center (NSSC), Chinese Academy of Sciences (CAS), 2022-present

• Associate Research Scientist, Division of Geological and Planetary Sciences, Caltech, 2019-2021

• Postdoctoral Scholar, Division of Geological and Planetary Sciences, Caltech, 2018-2019

• NASA Postdoctoral Program (NPP) Fellow, Jet Propulsion Laboratory (JPL), Caltech, 2016-2018

• Research assistant, Microwave Remote Sensing Laboratory (MIRSL), University of Massachusetts Amherst, 2010-2016

• Offers the Electrical Engineering course “InSAR Terrestrial Remote Sensing Theory and New Approaches” at the University of Chinese Academy of Sciences (graduate-level; summer school)

• Assisted in teaching two Electrical & Computer Engineering courses at UMass Amherst: “Electromagnetic Field Theory” (graduate-level; Fall 2013) and “Microwave Engineering” (undergraduate/graduate-level; Fall 2014).

• ​Gave an invited lecture in the Department of Geosciences at UMass Amherst on microwave remote sensing for the undergraduate-level course “Remote Sensing and Image Interpretation” (Spring 2012).

JOURNAL PUBLICATIONS

1. Y. Lei, A. Gardner, P. Agram, “Processing Methodology for the ITS_LIVE Sentinel-1 ice velocity product,” Earth System Science Data, 2022, https://doi.org/10.5194/essd-2021-393. (Preprint)
2. Y. Lei, X. Xu, C. Baldi, J.W. De Bleser, S. Yueh, D. Esteban-Fernandez, K. Elder, B. Starr, and P. Siqueira, “Dry Snow Parameter Retrieval with Ground-based Single-Pass Synthetic Aperture Radar Interferometry”, IEEE Transactions on Geoscience and Remote Sensing, 2022, doi: 10.1109/TGRS.2022.3171269. 
3. Y. Lei, M. Raguso, M. Mastrogiuseppe; C. Elachi, M. Haynes, “Validation of a Pseudospectral Time-Domain (PSTD) Planetary Radar Sounding Simulator with SHARAD radar sounding data”, IEEE Transactions on Geoscience and Remote Sensing, 2022, 60, 1-15, Art no. 2004515, doi: 10.1109/TGRS.2022.3168283.
4. H.B. Parache, T. Mayer, K.E. Herndon, A.I. Flores-Anderson, Y. Lei, Q. Nguyen, T. Kunlamai and R. Griffin, “Estimating Forest Stand Height in Savannakhet, Lao PDR Using InSAR and Backscatter Methods with L-Band SAR Data”, Remote Sensing, 2021, 13(22), 4516.
5. Y. Lei, A. Gardner, P. Agram, “autonomous Repeat Image Feature Tracking (autoRIFT) and its application for tracking ice displacement,” Remote Sensing, 2021, 13(4), 749.
6. Y. Lei, R. Treuhaft, F. Goncalves, “Automated estimation of forest height and underlying topography over a Brazilian tropical forest with single-baseline single-polarization TanDEM-X SAR interferometry,” Remote Sensing of Environment, 2021, 252, 112132.
7. Y. Lei, M. Haynes, D. Arumugam, C. Elachi, “A 2-D Pseudospectral Time-domain (PSTD) simulator for large-scale electromagnetic scattering and radar sounding applications,” IEEE Transactions on Geoscience and Remote Sensing, 2020, 58(6), 4076-4098.
8. Y. Lei, P. Siqueira, N. Torbick, M. Ducey, D. Chowdhury, W. Salas, “Generation of large-scale moderate-resolution forest height mosaic with spaceborne repeat-pass SAR interferometry and lidar,” IEEE Transactions on Geoscience and Remote Sensing, 2018, 57(2), 770-787.
9. Y. Lei, R. Treuhaft, M. Keller, M. dos-Santos, M. Neumann, F. Goncalves, “Quantification of selective logging in tropical forest with spaceborne SAR interferometry,” Remote Sensing of Environment, 2018, 211, 167-183.
10. Y. Lei, R. Lucas, P. Siqueira, M. Schmidt, R. Treuhaft, “Detection of forest disturbance with spaceborne repeat-pass SAR interferometry,” IEEE Transactions on Geoscience and Remote Sensing, 2018, 56(4), 2424-2439 (journal cover page).
11. R. Treuhaft, Y. Lei, F. Goncalves, M. Keller, J. dos Santos, M. Neumann, “Tropical-Forest Structure and Biomass Dynamics from TanDEM-X Radar Interferometry,” Forests, 2017, 8, 277.
12. Y. Lei, P. Siqueira, R. Treuhaft, “A physical scattering model of repeat-pass InSAR correlation for vegetation,” Waves in Random and Complex Media, 2017, 27(1), 129-152.
13. Y. Lei, P. Siqueira, R. Treuhaft, “A dense-medium electromagnetic scattering model for the InSAR correlation of snow,” Radio Science, 2016, 51(5), 461-480.
14. Y. Lei, P. Siqueira, “An automatic mosaicking algorithm for the generation of a large-scale forest height map using spaceborne repeat-pass InSAR correlation magnitude,” Remote Sensing, 2015, 7(5), 5639-5659.
15. Y. Lei, P. Siqueira, “Estimation of forest height using spaceborne repeat-pass L-band InSAR correlation magnitude over the US state of Maine,” Remote Sensing, 2014, 6(11), 10252-10285.

CONFERENCE PUBLICATIONS

1. Y. Lei, P. Siqueira, “Refined forest stand height inversion approach using spaceborne repeat-pass L-band SAR interferometry and GEDI lidar data,” IEEE International Geoscience and Remote Sensing Symposium (IGARSS), Kuala Lumpur, 2022.
2.  Y. Lei, A. Gardner, and P. Agram, “A fast dense feature tracking routine with its application in cryosphere remote sensing using Sentinel-1 and Landsat-8 data,” IGARSS, Hawaii, 2020.
3. Y. Lei, M. Haynes, D. Arumugam, and C. Elachi, “A pseudospectral time-domain simulator for large-scale half-space electromagnetic scattering and radar sounding applications,” IGARSS, Hawaii, 2020.
4. Y. Lei, R. Robert, and F. Goncalves, “Tropical forest height and underlying topography from TanDEM-X SAR Interferometry,” IGARSS, Hawaii, 2020.
5. X. Xu, C. Baldi, J.W. De Bleser, Y. Lei (lead for SAR data processing and snow inversion algorithms), S. Yueh, and D. Esteban-Fernandez, “Multi-frequency Tomography Radar Observations of Snow Stratigraphy at Fraser during SnowEx,” IGARSS, Valencia, 2018.
6. Y. Lei, R. Treuhaft, R. Lucas, P. Siqueira, M. Keller, M. Schmidt, “Large-scale fine-resolution products of forest disturbance using new approaches from spaceborne SAR interferometry,” IGARSS, Fort Worth, 2017.
7. Y. Lei, P. Siqueira, Nathan Torbick, D. Chowdhury, W. Salas, R. Treuhaft, “Large-scale fine-resolution product of forest height using a new approach from spaceborne repeat-pass SAR interferometry and lidar,” IGARSS, Fort Worth, 2017(session chair).
8. Y. Lei, P. Siqueira, D. Chowdhury, Nathan Torbick, “Generation of large-scale forest height mosaic and forest disturbance map through the combination of spaceborne repeat-pass InSAR coherence and airborne lidar,” IGARSS, Beijing, 2016.
9. Y. Lei, P. Siqueira, “A dense-medium InSAR correlation model with its application to the problem of snow characteristics retrieval,” IGARSS, Milan, 2015.
10. Y. Lei, P. Siqueira, “An automatic mosaicking algorithm for generating a large-scale forest stand height map using spaceborne repeat-pass InSAR coherence,” IGARSS, Quebec, 2014.
11. Y. Lei, P. Siqueira, D. Clewley, and R. Lucas, “Observation of vegetation vertical structure and distribution using L-band InSAR over the Injune region in Australia,” IGARSS, Munich, 2012.
12. Y. Lei, R. Mettu, “A confidence measure for model fitting with X-ray crystallography data,” ACM Conference on Bioinformatics, Computational Biology and Biomedical Informatics, Washington DC, 2013.
13. Y. Lei, X. Xu, “Spectrum-Division Analysis of Precursor Fields Propagating in Dispersive Media”, IET International Radar Conference, Guilin, China, April, 2009.

• Synthetic Aperture Radar (SAR), Interferometric SAR (InSAR), Polarimetric InSAR (PolInSAR) and Tomographic SAR (TomoSAR) data processing with remote sensing applications;

• Physics-based retrieval algorithm development for radar remote sensing observations of random and complex medium (e.g. vegetation, snow, ice, planetary subsurface);

• Radar remote sensing theory (e.g. electromagnetic scattering modeling and simulation) for earth and planetary remote sensing applications;

• Development of automated radar remote sensing software;

• Large-scale algorithm/product validation with multi-type/sensor remote sensing dataset (e.g. spaceborne/airborne radar, lidar, passive optical sensor, and field inventory data).

INVITED TALKS 

1. Y. Lei, “Large-scale forest height and disturbance mapping through spaceborne SAR interferometry (InSAR): on the fusion of NISAR and GEDI along with TanDEM-X/L,” NASA/JPL Carbon Club, Radar Forum and Postdoc Seminar Series (presented at three events), Pasadena, 2018.
2. Y. Lei, R. Treuhaft, P. Siqueira, N. Torbick, R. Lucas, M. Keller, M. Schmidt, M. Ducey, W. Salas, “Generation of large-scale forest height and disturbance maps through the fusion of NISAR and GEDI along with TanDEM-X/L,” AGU Fall Meeting, New Orleans, 2017.
3. C. Baldi, J.W. De Bleser, K. Elder, D. Esteban-Fernandez, B. Starr, X. Xu, Y. Lei (presenting author and lead for SAR data processing and snow inversion algorithms) and S. Yueh, “Preliminary Results from Fielding an In Situ Three-Frequency Tomographic Radar on Snowpack,” NASA SnowEx Workshop, Longmont, Colorado, 2017.
4. Y. Lei, “Automated generation of large-scale high-resolution forest height and disturbance maps for NISAR-like missions,” NASA/JPL NISAR Science Definition Team Meeting, Pasadena, 2017.
5. Y. Lei, R. Treuhaft, P. Siqueira, R. Lucas, M. Keller, M. Schmidt, M. Neumann, F. Goncalves, “Detection of forest disturbance using spaceborne single-pass and repeat-pass SAR interferometry,” ESA PolInSAR meeting, Rome, Italy, 2017.
6. Y. Lei, “Electromagnetic scattering models of InSAR correlation for vegetation and snow,” NASA/JPL Radar Forum, Pasadena, 2015.
7. P. Siqueira, Y. Lei (presenting author), “Repeat-pass InSAR processing for Vegetation Height Calculation: Theory and a validated example,” AGU Fall Meeting, San Francisco, 2014.

01/2022            Excellent Young Scientists by National Natural Science Foundation of China

10/2021            NISAR Team Award on tropospheric model down-selection by NASA/JPL 

10/2015            NASA Postdoctoral Program (NPP) fellowship (2016-2018) by NASA (applicant pool acceptance rate of 2%)

05/2012            NASA Earth and Space Science Fellowship (NESSF) (2012-2015) by NASA (acceptance rate of 18.8%)

05/2017            2017 ECE Departmental Dissertation Prize by UMass Amherst (1 prize every year)

10/2013            Second Prize for the 2013 ECE Departmental PhD Poster Session by UMass Amherst

Topical Associate Editor, IEEE Transactions on Geoscience and Remote Sensing, 2022-present

IEEE Senior Member, IEEE Geoscience and Remote Sensing Society, 2022-present

InSAR Terrestrial Remote Sensing Theory and New Approaches
Radar Remote Sensing
Electromagnetic Field Theory
Microwave Engineering
Introduction to Radar Systems
Radar Signal Processing

Proposal Title: Synthetic Aperture Radar (SAR) Remote Sensing of Terrestrial Environment 
PI: Yang Lei 
Source: National Natural Science Foundation of China’s Excellent Young Scientists Fund Program 
Period: 2022-2025 

Proposal Title: Generation of large-scale forest height/biomass and change/disturbance products by leveraging JAXA’s ALOS-2/ALOS-4 InSAR data in fusion with MOLI lidar data 
PI: Yang Lei 
Source: Japan Aerospace Exploration Agency (JAXA) 3rd Research Announcement on the Earth Observations 
Period: 2022-2025 

Proposal Title: Monitoring large-scale forest change and disturbance with TanDEM-X SAR interferometry 
PI: Yang Lei 
Source: German Aerospace Center (DLR) TerraSAR-X/TanDEM-X CoSSC Data Proposal 
Period: 2021- 

Proposal Title: Multilayer Forward Model Using SnowEx and TomoSAR Datasets at X/Ku-band 
PI: Xiaolan Xu 
Co-I: Yang Lei 
Source: NASA Terrestrial Hydrology Program (ROSES 2017 A.25) 
Period: 2018-2020 

Proposal Title: Generation of the Global Forest Height and Disturbance Maps through the Fusion of NISAR and GEDI: to Regain the Promise of DESDynI 
PI: Robert Treuhaft (Postdoc advisor) 
Postdoc: Yang Lei (author of the proposal) 
Source: NASA Postdoctoral Program (NPP) 
Period: 2016-2018 

Proposal Title: Determination of Vegetation Vertical Structural Profile and Changes for DESDynI-like missions Utilizing InSAR and PolInSAR Techniques 
PI: Paul Siqueira (PhD advisor) 
Graduate Student: Yang Lei (author of the proposal) 
Source: NASA Earth and Space Science Fellowship (NESSF) 
Period: 2012-2015

• Forest Stand Height (FSH) inversion and mosaicking software: https://github.com/leiyangleon/FSH 

• Pseudospectral Time-domain (PSTD) simulator (a large-scale electromagnetic scattering and radar sounding simulator): https://github.com/leiyangleon/PSTD 

• autoRIFT (autonomous Repeat Image Feature Tracking): https://github.com/nasa-jpl/autoRIFT 

• Geogrid (geocoding software for mapping between [pixel index, offset] in radar/optical image coordinates and [geolocation, velocity] in map coordinates): https://github.com/leiyangleon/Geogrid

ResearchGate Profile

https://www.researchgate.net/profile/Yang_Lei23 

GoogleScholar Profile

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