Various aspects of tropical cyclones (TCs) fluctuate with the diurnal cycle. TC size is critical to the extent of its damage, but diurnal variations in the growth of the outer region size have largely remained unexplored. This paper examines the diurnal variations in the growth of the radius of gale-force winds (34 kt; R34) by analyzing best-track data from 2001 to 2019 for both North Atlantic TCs and global TCs outside of the North Atlantic region. Statistically significant diurnal variations was found for R34 growth, with the maximum 6-h growth rate occurring at 2100–0300 local solar time (LST) for North Atlantic TCs, and at 0300–0900 LST for global TCs excluding the North Atlantic which experienced rapid intensification (≥30 knots within 24 h). The higher R34 6-h growth rates during the night were linked to a larger extent of very deep convective clouds with infrared brightness temperatures <208 K during this time.

中文翻译：

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热带气旋外围区域大小增长的日变化

热带气旋 (TC) 的各个方面随着昼夜周期而波动。热带气旋的大小对其损害程度至关重要，但外部区域大小增长的日变化在很大程度上仍未被探索。本文通过分析 2001 年至 2019 年北大西洋热带气旋和北大西洋地区以外的全球热带气旋的最佳轨迹数据，研究了大风（34 节；R34）半径增长的日变化。R34 生长具有统计上显着的日变化，北大西洋 TC 的最大 6 小时增长率出现在当地太阳时 (LST) 2100-0300，全球 TC 出现在 0300-0900 LST（不包括北大西洋）。强度（24小时内≥30节）。夜间较高的 R34 6 小时增长率与在此期间红外亮度温度 <208 K 的较大范围的极深对流云有关。