Increasing risk from landfalling tropical cyclone-heatwave compound events to coastal and inland China

Tropical cyclones (TCs) and heatwaves are amongst the most deadly and costly natural hazards. Despite considerable advances in understanding each of them, their occurrences in rapid sequence (e.g. in a week) that introduce disproportionately large impacts to infrastructure and human health have received far less attention. Based on dynamical downscaling simulations, we project that currently rare landfalling TC-heatwave compound events would be five to ten times more frequent in coastal Southeast China, and migrate northward and westward to the intact interior. It is the substantial increase in heatwaves that contributes most to the projected increase in frequency and novel emergence of compound events. There would be higher fraction of severer compound events composed of either intense TCs (in the top 10% historically) or exceptional heatwaves (above the historical 99.9th percentile), with coastal Southeast China even bracing for out-of-ordinary combinations of the two. On top of the unprecedented frequency, intensity and land exposure, future emergence of unseasonal compound events in South and Southeast China would further overwhelm local adaptive capacities

Water Hammer Protection Characteristics and Hydraulic Performance of a Novel Air Chamber with an Adjustable Central Standpipe in a Pressurized Water Supply System

Water scarcity is an urgent issue for social and economic development in arid and semi-arid areas. Constructing long-distance pressurized water supply projects is a commonly used measure to solve water scarcity problems in these areas. With the increasing complexity of long-distance pressurized water supply projects, the issue of water hammer protection has become more and more prominent. Air chambers have been widely used to solve the issue of water hammer accidents. In this paper, we propose a novel air chamber with an adjustable central standpipe, and then analyze the hydraulic performance, as well as the water hammer protection characteristics, of the proposed novel air chamber using numerical simulations. The influences of the inner length, the diameter of the central standpipe, and the diameter of the bottom connecting pipe on the hydraulic performance of the air chamber are also studied. Then, the optimization of the relevant parameters of the central standpipe for the proposed air chamber is conducted. In addition, the volumes of the proposed air chamber and conventional air chambers are compared