Characteristics and Causes of Extreme Rainfall Induced by Binary Tropical Cyclones over China

Abstract

Binary tropical cyclones (BTC) often bring disastrous rainfall to China. From the viewpoint of the extreme of the BTC maximum daily rainfall, the characteristics of BTC extreme rainfall (BTCER) during 1960-2018 are analyzed, using daily rainfall data; and some representative large-scale mean flows, in which the associated BTCs are embedded, are analyzed. Results show that the frequency of BTCER shows a decreasing trend [−0.49 (10 yr) −1 ] and is mainly distributed within the BTC heavy rainstorm interval (100 mm ≤ BTCER <250 mm). BTCER occurs mostly from July to September with a peak in August. Three BTCER typical regions-Minbei, the Pearl River Delta (PRD), and Taiwan-are identified according to the clustering of stations with high BTCER frequency and large BTCER. A further analysis of the 850-hPa BTC composite horizontal wind and water vapor flux over the PRD region shows the existence of two water vapor transport channels, which transport water vapor to the western tropical cyclone. In the first of these channels, the transport takes place via the southwest monsoon, which accounts for 58% of the total moisture, and an easterly flow associated with eastern tropical cyclone accounts for the remaining 42%.

Temporal and Spatial Impact of Precipitable Water Vapor on GPS Relative Positioning During the Tropical Cyclone Hato (2017) in Hong Kong and Taiwan

“…The normalized magnitude in Hong Kong was smaller than that in Taiwan. That was primarily due to the different terrains of Hong Kong and Taiwan (Bao et al., 2017; Wang et al., 2020; Yeh et al., 2016). The east coast of Taiwan is mountainous, which blocks most of PWV flux from the sea.…”

Rainfall Differences and Possible Causes of Similar-Track Tropical Cyclones Affected and Unaffected by Binary Tropical Cyclones (BTCs) in China

“…In contrast, the PDF curve of Factors such as translation speed and intensity have a significant impact on TC precipitation [39,64,65]. Moreover, many studies have shown that the BTC effect causes the track of TCs to change irregularly and suddenly [23,26,27,29,32]. Therefore, we consider the translation speed (V = distance(P t+1 − P t−1 )/2t, where P t−1 and P t+1 represent the TC positions at the previous and next time steps, respectively), intensity, and direction change (∆θ = abs(θ t − θ t−1 ), where θ t = direction(P t − P t−1 ), θ t = 0 • , 90 moving eastward, northward, westward, and southward, respectively) as factors that may influence typhoon precipitation for diagnostic analysis.…”

More or Less: How Do Inhomogeneous Sea‐Salt Aerosols Affect the Precipitation of Landfalling Tropical Cyclones?

“…Tropical cyclones (TCs) are one of the severe weather systems, which often cause huge economic losses and casualties with extreme winds, storm surges, and/or torrential rainfall in the coastal regions and on some inlands (M. Wang et al., 2021; Yu, 2015). Accurate forecast of TC rainfall is necessary for management of fresh water resources and rainfall‐induced disaster warning system (Wu et al., 2018).…”

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Tropical cyclones (TCs) are one of the severe weather systems, which often cause huge economic losses and casualties with extreme winds, storm surges, and/or torrential rainfall in the coastal regions and on some inlands (M. Wang et al, 2021;Yu, 2015). Accurate forecast of TC rainfall is necessary for management of fresh water resources and rainfall-induced disaster warning system (Wu et al, 2018).In recent years, many progresses have been made in TC track forecasting, owing to the advancements in observational technology, numerical models and our understanding of underlying physics.

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