Research

Satellite-based post-tornado assessments have been widely used for the detection of tornado tracks, which heavily relies on the identification of vegetation changes through observations at visible and near-infrared channels. During the deadly 10–11 December 2021 tornado outbreak, a series of violent tornadoes first touched down over northeastern Arkansas, an area dominated by cropland with rare vegetation coverage in winter. Through the examination of Moderate Resolution Imaging Spectroradiometer multi-spectral observations, this study reveals significant scars on shortwave infrared channels over this region, but none are captured by visible and near-infrared channels. The dominant soil type is aquert (one of vertisols), whose high clay content well preserves the severe changes in soil structure during the tornado passage, when the topmost soil layer was removed and underlying soil with higher moisture content was exposed to the air. This study suggests a quick post-tornado assessment method over less vegetated area by using shortwave infrared channels. 

Wang, J., Lin, Y., McFarquhar, G. M., Park, E., Gu, Y., Su, Q., et al. (2023). Soil moisture observations from shortwave infrared channels reveal tornado tracks: A case in 10–11 December 2021 tornado outbreak. Geophysical Research Letters, 50, e2023GL102984. https://doi.org/10.1029/2023GL102984 

Hail and tornadoes are hazardous weather events that are responsible for significant property damage and economic loss world-wide. The most devastating hail and tornado events are commonly produced by supercells in the United States. However, some hazard-producing supercells may grow upscale into mesoscale convective systems (MCSs) or may be 10 embedded in MCSs. Quantifying the relationship of hail and tornado occurrences with MCSs on the long-term climatology is lacking. In this work, the radar features associated with MCSs are extracted from a 14-year MCS tracking database over the contiguous United States, and the hazard reports are matched to the extracted MCS features. We analyze the characteristics of hail and tornadoes associated with MCS characteristics and consider the seasonal and regional variabilities. On average, about 8-17% of hail and 17-32% of tornado events are associated with MCSs depending on various criteria used to define 15 MCSs. The maximum total and MCS-associated hazard events occur in March-May, but the highest MCS-associated portion (23% for hail and 45% for tornado) occurs in winter (December-February) because MCS is the dominant type of convection due to strong synoptic forcing. In contrast to the decreasing trend in the relationship of MCS-associated fraction with hailstone size, the more severe the tornado event is, the more likely it is associated with an MCS. The different trends indicate the distinct mechanisms for the MCS-associated production of the two types of hazards. 

Wang, Jingyu & Fan, Jiwen & Feng, Zhe. (2023). Climatological occurrences of hail and tornado associated with mesoscale convective systems in the United States. 10.5194/nhess-2023-16. 

The North China Plain (NCP) is globally known for wheat production as well as smoke emission from wheat straw burning after harvest in June. The open straw burning has widespread impacts on climate, biogeochemical cycles, and human well-being through changes in global and regional aerosol concentrations. Although some short-term efforts were successful in suppressing the NCP’s open straw burning in certain years, the Chinese government has been criticized for its ineffective long-term fire management for decades. Triggered by the 2012-2013 winter air pollution crisis, China launched the most stringent legislation to control air pollution. Besides the improvement in air quality, the NCP’s fire carbon emission has been substantially reduced from 4 MtCO2-eq yr-1 in 1997-2016 to 1 MtCO2-eq yr-1 in 2017-2021, while the contemporary global emission from biomass burning has increased by 20 MtCO2-eq yr-1. Noteworthy that this is only one specific type of crop during one harvest season, therefore China’s open straw burning bans may have achieved a much more prodigious triumph in reducing fire carbon emission, which warrants further investigation. 

Wang, Jingyu & Wang, Xianfeng. (2023). A triumph of reducing carbon emission by banning open straw burning. 68. 10.1016/j.scib.2022.12.029.