Yakun Liu

• Massachusetts Institute of Technology

Plain Language Summary Noteworthy global reductions in pollution emission are evident in the COVID pandemic year 2020 with the sharp decrease of anthropogenic activity and attendant reduction in energy consumption. A globally averaged reduction of 7.6% in Aerosol Optical Depth (AOD) is identified from MODIS satellite observations. Aerosol effects a...

The importance of lightning has long been recognized from the point of view of climate‐related phenomena. However, the detailed investigation of lightning on global scales is currently hindered by the incomplete and spatially uneven detection efficiency of ground‐based global lightning detection networks and by the restricted spatio‐temporal covera...

The importance of lightning has long been recognized from the point of view of climate-related phenomena. However, the detailed investigation of lightning on global scales is currently hindered by the incomplete and spatially uneven detection efficiency of ground-based global lightning detection networks and by the restricted spatio-temporal covera...

This book highlights the essential theoretical and practical aspects of lightning, lightning protection, safety and education. Additionally, several auxiliary topics that are required to understand the core themes are also included. The main objective of the contents is to enlighten the scientists, researchers, engineers and social activists (inclu...

This chapter is concerned with the remote detection and analysis of thunderstorms and lightning flashes by electrostatic, electromagnetic and photographic means, and the use of these methods for public warning of hazardous conditions. Section 1 addresses the measurement of electrostatic fields in fair weather and in response to the stronger fields...

Plain Language Summary The notorious 2019–2020 Australian wildfire devastated >46 million acres of land and heavily contaminated the atmosphere over the Australian continent and offshore regions. In conditions of moist convection over the polluted ocean, massive heat from wildfires on land is ineffectual and aerosol effects can be disentangled from...

The laboratory lightning testing commonly uses an indirect electrode as the current injection configuration to restraint the electrode jet for evaluation of lightning strike damage tolerance of aircraft materials. Such an indirect electrode configuration requires using a conductive ignition wire to initiate the arc. This work discusses the influenc...

The damage depth of a material is a key parameter for industrial objects in consideration of the lightning threat. The continuing current component in a multiple lightning sequence features a large charge transfer, which often leads to the dominant damage depth for electrically conductive materials. Laboratory simulation of the lightning continuing...

Multistation observations of Schumann resonance (SR) intensity document common behavior in the evolution of continental‐scale lightning activity in two super El Niño events, occurring in 1997/98 and 2015/16. The vertical electric field component of SR at Nagycenk, Hungary and the two horizontal magnetic field components in Rhode Island, USA in 1997...

Understanding the damage mechanisms of fiber-reinforced polymer matrix composite materials under high voltage conditions is of great significance for lightning strike protection and high voltage insulation applications of composite structures. In this paper, we investigated effects of the lightning impulse (LI) voltage and high voltage alternating...

Plain Language Summary Over adjacent oceanic regions, the thermodynamic contrast is indistinct, and this makes oceanic lightning a sensitive indicator of aerosol effects. The southern South China Sea, surrounded by wideband electric‐field sensors in Earth Networks Total Lightning Network, is focused on the response of both intracloud (IC) and cloud...

Investigating the effects of single impulse current (SIC) and multiwaveform multipulse currents (MWMPCs) on metal contributes to the body of knowledge on lightning damage characteristics and mechanisms. This information is the basis for lightning protection of metal-made structures such as oil tanks, wires, and aircraft. In this article, three typi...

The micro ablation characteristics of steel inflicted by the lightning currents and the influence of anti-corrosion coating on these characteristics are seldom investigated, even though fundamental to applications of steel. In this work, ablation tests on uncoated and coated mild steel plates were conducted with the 2 ms rectangular current simulat...

This paper elucidates the damage characteristics, microstructure response and temperature rise of steel alloy Q235B suffered from lightning currents, which is the basis for lightning protection of oil tanks. Damage is inflicted in the designed Q235B specimens by using the multi-waveform multi-pulse impulse current generator to characterize the dama...

The front-face temperature rise of Al alloy subjected to the high-energy long continuing current (LCC) component in lightning is important but difficult to measure. Therefore, a numerical inversion model based on the control volume finite element method is proposed to analyse the front-face temperature rise of Al alloy deduced from the rear-face te...

The understanding on the response of aluminum alloy to direct lightning currents is needed for lightning protection. Four typical lightning current components, which are the first return stroke current, subsequent return stroke current, continuing current in the stroke intervals, and long continuing current, are simulated to investigate their damag...

The damage of two typical metal materials, Al alloy 3003 and steel alloy Q235B, subjected to four representative lightning current components are investigated by laboratory and analytical studies to provide fundamental data for lightning protection. The four lightning components simulating the natural lightning consist of the first return stroke, t...

Research on damage characteristics and mechanisms of aluminum alloy struck by lightning is one of the basis for lightning protection of oil tanks. Thus, using the simulated lightning current experiment method, we experimentally investigated 3003 aluminum alloy material, which is widely used in oil storage, with different components of lightning cur...

Due to the lack of reseaeching the influential factors of experiment on metal materials struck by simulated lightning currents in China and at abroad, we investigated the influences of electrode shape, copper fuse, and experiment distance on metal damage results based on experimental and theoretical methods. The results show that, in the metal dama...

Metal ablation area and depth are affected by electrodes used in simulated lightning metal ablation experiment. In this study, electrode materials are firstly investigated to decrease electrode jet. Then nine different shapes of experiment electrodes, which are hemisphere electrode, semi-ellipsoid electrode and cone electrode with three different d...

Research on ablation damage and temperature rise of the metal oil tanks struck by direct lightning is the basis for lightning protection of metal oil tanks. We experimentally researched the ablation damage and temperature rise of metal oil tank's common materials steel alloy Q235B and aluminum alloy 3003 caused by direct lightning. Moreover, we ana...

Lightning is one of the major hazards for large floating oil tanks. In order to research the effect of indirect lightning on floating roof oil tanks, this paper proposes a numerical procedure based on finite difference time domain (FDTD) method to analyze the electric field strength distribution on large floating oil tanks and calculate the lightni...

According to the statistical data, lightning strike is the major cause of the large floating oil tanks ignition. The accident is usually caused by the direct and indirect lightning stroke. The effects of direct lightning stroke on floating oil tank have been studied a lot in previous works and there is little research on the influence of lightning...