Greater flood risks in response to slowdown of tropical cyclones over the coast of China

Abstract

<jats:p>The total amount of rainfall associated with tropical cyclones (TCs) over a given region is proportional to rainfall intensity and the inverse of TC translation speed. Although the contributions of increase in rainfall intensity to larger total rainfall amounts have been extensively examined, observational evidence on impacts of the recently reported but still debated long-term slowdown of TCs on local total rainfall amounts is limited. Here, we find that both observations and the multimodel ensemble of Global Climate Model simulations show a significant slowdown of TCs (11% in observations and 10% in simulations, respectively) from 1961 to 2017 over the coast of China. Our analyses of long-term observations find a significant increase in the 90th percentile of TC-induced local rainfall totals and significant inverse relationships between TC translation speeds and local rainfall totals over the study period. The study also shows that TCs with lower translation speed and higher rainfall totals occurred more frequently after 1990 in the Pearl River Delta in southern China. Our probability analysis indicates that slow-moving TCs are more likely to generate heavy rainfall of higher total amounts than fast-moving TCs. Our findings suggest that slowdown of TCs tends to elevate local rainfall totals and thus impose greater flood risks at the regional scale.</jats:p>

Compound flood potential from storm surge and heavy precipitation in coastal China

“…Meanwhile, other flood drivers, such as precipitation, river discharge, waves, and TCs, can also exhibit nonstationarity leading to increased (compound) flood risk (Kundzewicz et al, 2019). Observations from the last five decades and numerical model studies (Lai et al, 2020) indicate a slowdown of TCs, which would likely favour more extreme rainfall during the events as compared to fast-moving TCs.…”

Tropical Cyclone Impacts on Cities: A Case of Hong Kong

“…Yet, it is still difficult to say for sure if the increase in TC-related damages in Hong Kong is due to this phenomenon as the significant TC hazard for economic losses in Hong Kong is found to be rainfall ( Table 2). TC rainfall is likely to intensify in a warmer climate and with a possible reduction in the translational speed of landfalling TCs, cities that are the most sensitive to rainfall (i.e., Hong Kong) are expected to experience higher TC rainfalls, and consequently a larger threat of flooding, particularly in the most active TC basins and the most developed coastlines in the world (Geert-Jan-Van et al, 2017;Kossin, 2018;Trenberth, 2018;Lai et al, 2020).…”

Four-dimensional evaluation and forecasting of marine carrying capacity in China: Empirical analysis based on the entropy method and grey Verhulst model

“…Limitations remain in this study. Although we scientifically select the evaluation index of the marine carrying capacity, but due to limited data, it fails to include more influencing factors, such as the economic loss caused by marine disasters ( Lai et al, 2020 ) as well as the resilience of coastal areas ( Tessler et al, 2015 ; Liu et al, 2017 ). Moreover, other commonly-used prediction method could be applied, such as the scenario-based analysis ( Niu et al, 2020 ), it is a method of making predictions about the likely occurrence or consequences of a predicted object on the premise that a phenomenon or trend will continue into the future.…”

“…Therefore, marine carrying capacity can be understood as actually conveying the largest support degree for human activities ( Liao et al, 2013 ; Tian et al, 2020 ). In this light, two aspects of the connotations of marine carrying capacity can be illustrated: on the one hand, oceans provide many resources necessary to support human society and to build the ocean-related industries, such as marine fisheries, exploitation of oil, gas, and minerals; on the other hand, oceans can accommodate a variety of pollutants produced by land-based economies, and this too is an important function provided by oceans ( Lai et al, 2020 ). Further, as marine carrying capacity includes both the productivity of the ocean and management ability, according to the China Sustainable Development Strategy Report 2000 ( Niu, 2000 ), enhancing marine carrying capacity has become a requirement for sustainable development in coastal regions, while the ongoing augmentation of marine carrying capacity facilitates oceans' sustainable development.…”