I obtained my PhD at Imperial College London's Space & Atmospheric Physics Group with NCEO and the Grantham Institute.

My primary research focuses on atmospheric radiative transfer modelling and satellite retrievals. In particular, I am interested in exploring how we can generate and model spectrally resolved irradiance based from satellite earth observations so that the global availability of solar energy resources can be better understood.

IMG_1779.JPG

on Solar Energy Resources & Satellite Observations

Recorded at EGU 2019, Vienna. Session ESSI1.16 Earth Observations for Sustainable Development (Tuesday 9th April (08:30–12:30))

Recorded at the Joint DTP Conference (Sep 2018) Session 4B: Novel Measurements & Solar.

Recorded at Imperial's Space & Atmospheric Physics Group

Recorded at the NCEO Conference (Sep 2018) Session 6A: Satellite ECV data asset and climate services.

Choi et al. (2020). Developing Automated Methods to Estimate Spectrally Resolved Direct Normal Irradiance for Solar Energy Applications. Renewable Energy. https://doi.org/10.1016/j.renene.2021.03.127


on COVID-19 Lockdown & Solar Energy Resources

Recorded for the PhD Summer Showcase 2020

Recorded at during the virtual NCEO conference 2020 (25 Jun 2020)

Presented at the NCEO Virtual Conference 2020. Using satellite observations of nitrogen dioxide (NO2) and aerosol optical depth during the COVID-19 lockdown, this study illustrates one of the potential hidden benefits of a cleaner atmosphere is more efficient large scale solar energy generation.

We estimate the change in broadband and spectrally resolved solar direct normal irradiance (DNI) at the surface over China from 15 February to 15 March 2019, and the same period in 2020. The latter period was chosen to coincide with the lockdown enforced due to the COVID-19 pandemic. Between the two periods, satellite observations show a widespread reduction in atmospheric NO2 concentrations and some notable changes to aerosol optical depth. Focusing on Wuhan, the first city to be placed under lockdown due to the pandemic, the combined changes in atmospheric species lead to a 19.8% increase in broadband surface DNI, along with a shift in the DNI spectral distribution towards bluer wavelengths. Feeding these changes into a solar cell simulator results in a 29.7% increase in the power output for a typical triple-junction concentrator photovoltaic cell (3J CPV). Around one-third of the increase in power output arises from the improved spectral matching between the input DNI spectrum and the solar cell, which in turn improved the 3J CPV operating efficiency by 2.6%. Similar spectral effects were also observed over Beijing and Shenzhen. Based on satellite observations, we estimate there was up to a 14% increase in 3J CPV efficiency over parts of China during the lockdown.

Choi et. al. (2020). COVID-19 lockdown air quality change implications for solar energy generation over China. Environ. Res. Lett. https://doi.org/10.1088/1748-9326/abd42f


Spatial & temporal Representativeness of AERONET sites

A collection of simple tools and results for quantitatively investigating the spatial and temporal representativeness of select AERONET sites.

spatiotemporal_correlation_for_all_sites.png

Other work

An interactive visualisation developed as part of my on-going PhD work shows the effects of how atmospheric constituents and viewing geometry affect the spectral circumsolar normal irradiance. For more, please refer to one of the presentation videos above.

An interactive playground that allows you to explore the effects of aerosols on the solar direct normal irradiance at ground level.

Can We Tell When COVID-19 Lockdown Began for Major Cities From Columnar Nitrogen Dioxide Observations from Satellite?

Authored articles on earth observations and climate change:

Choi, K. T. (2019). The role of climate services in handling climate change risks: Contributions of UKCP18. Weather, 74(7), 255-256. doi:10.1002/wea.3526

Choi, K. T. (2018). Space, satellite and solutions: Essential climate variables and the future of climate monitoring from space. Weather,73(12), 390-391. doi:10.1002/wea.3306


Outreach Work: RAISING AWAIRNESS: THE BOARD GAME

Raising awAIRness is a simple board game designed to educate young kids about the potential exposure to air pollution as one commute across London. Designed and presented at the Imperial Festival 2018.

Outreach Work: The Climate Action Advocate Programme for Scouts

The Climate Action Advocate Programme is a self-contained, six week, activity-filled programme designed specifically to be a fun and hands-on way to communicate climate change to a new demographic, and to empower them to sustain climate action. Aimed at young teenagers, these activities have been developed by PhD students at the Imperial College London’s Science and Solutions for a Changing Planet Doctoral Training Partnership.