Philip Lewis

I have focused on developing and applying new methods in this area, with a key emphasis on moving the field from loose empirical correlations to making use of physically-based models and combining models and measurements with Bayesian methods/data assimilation.

• Feng Yin
• Wanxin Yang (2nd supervisor)

I have sought to develop a strong, rigorous, capability in modelling which has led to a wide range of fruitful collaborations and data products over the years. My early work on 3D radiative transfer in vegetation canopies is still relevant today, indeed more so as we move to finer resolutions in space and time from EO and need to consider such effects.

I have applied my work to practical monitoring data products from EO for various biophysical parameters. This includes his work developing the NASA MODIS BRDF/albedo product with colleagues at Boston University and others, as well as early work in model-based global fire-affected area mapping from space. I developed the algorithm for the ESA GlobAlbedo product and am currently working on the surface reflectance product algorithm for the proposed ESA TRUTHS mission.

My work within NERC NCEO included robust data assimilation (DA) approaches linking data and models, and the development of Analysis Ready Data (ARD) from Sentinel-2, using a novel atmospheric correction DA approach. With my research group at UCL, we are developing and testing an ARD-LAI product with associated uncertainty to drive crop monitoring and other vegetation monitoring work. I work on the theory to develop this into a wider suite of biophysical products for vegetation (especially agricultural) monitoring.

I have worked with colleagues in radar modelling to explore common links between information in the optical and microwave domains and develop common 3D models. I have undertaken various fundamental work for ESA, STFC and NERC on canopy lidar and related instrumentation modelling.

In recent years, I have worked on agricultural monitoring using EO and data assimilation for yield estimation. I have various national/international collaborations, including current work with colleagues in China, Ghana and South Africa.

Much of my work has been NERC and ESA funded, alongside commercial collaboration. Beneficiaries of this work include scientists in related disciplines (constraining models with EO measurements; DA methods/tracking of uncertainty; new models and simulation tools); users of environmental monitoring data (through involvement in the development of global products for albedo and burned area estimation from NASA and ESA); and policy-makers and Government users such as BIS/DEFRA. 

The MODIS BRDF/Albedo product that I was involved in developing has been continuously generated globally, at 500m resolution since 2000. It is very widely used and has had a range of impacts. 
I was co-awarded to the 2019 Newton Award Chair’s Prize for the impact of my agricultural remote sensing work.
I presented my agricultural work to the conference of parties at COP26.

• 2023-24 ESA/AU EO-AFRICA-RDF BIG-ACE
• 2022-23 EU Sentinel-2 Global Mosaic (S2GM)
• 2021-23 ESA/NPL TRUTHS Mission Accompanying Consolidation Study
• 2014-26 NERC National Centre for Earth Observation ~£500K p.a.
• 2020-22 BEIS Newton Prize: Building Capacity for Crop Monitoring in Ghana £459K
• 2020-22 STFC Advancing MAiZe INformation for Ghana £404K
• 2016-20 STFC Regional crop monitoring with quant. Rem. sens. & data assim. £918K
• 2016-18 EU, MULTiscale Sentinel Land Surface Information Retrieval Platform, £621K
• 2015-16 STFC, Assimilating EO Data into Crop Growth Models, £250K + £45K

• 2014-15 ESA FLEX-Bridge £10K

• 2014-16 ESA Optirad £86K
• 2014-17 EU FP7 QA4ECV £120K
• 2014-17 ESA, SEOM SY-4SCI SYNERGY Th:2 Sentinel-2/3 land products, £100K