长江干线航道东段小时尺度降雨气候态时空特征研究

Spatiotemporal Characteristics of Hourly Rainfall in the Eastern Section of the Yangtze River Main Waterway

摘要: 降水对长江航道上的船舶航行安全及航运的运营成本都有着至关重要的影响。由于复杂的地形地貌，已有研究不能满足长江内河航运在空间上精细化的需求。本研究采用CMORPH和GSMaP两套遥感降水数据在小时尺度上对长江下游航道东段小时尺度降雨气候态特征进行研究分析。研究结果表明：在月尺度上，九月是月降水增加最剧烈的月份，在冷季(12月至次年1月)，GSMaP和CMORPH_ADJ呈现微弱的减弱趋势；在多年日平均小时数据中，除梅雨显著特征外，8月上旬和下旬、9月中旬和9月底、10月上旬和下旬、11月上旬和下旬均出现全航段降水现象；对于降水强度的小时统计，在月尺度不同强度降水时间统计上，GSMaP数据小雨时间降水小时数增加的区域主要集中在江阴至扬中航段。CMORPH_ADJ中，小时数增长趋势发生主要在九月，增幅在0.6 h/yr，其余时段处于减少趋势。GSMaP能够反映在此时间内增加的趋势，CMORPH_ADJ反映出微弱的减少趋势。GSMaP还反映9月中雨小时数呈增加趋势(1 h/yr)。中雨以上的小时数，主要在五月中旬至八月底，这些年有微弱的增加趋势导致夏季航运成本增加显著。综上，本文细致的研究了长江下游航道降水小时气候特征，有助于提高长江黄金水道航运安全性和降低运输成本。

Abstract: Precipitation is a crucial factor affecting shipping safety and transportation costs on the Yangtze River waterway. However, due to the complex terrain of the region, previous research has not been able to provide spatial refinement to meet the demands of inland water transportation. To address this gap, we utilized two remote sensing precipitation datasets, CMORPH and GSMaP, to investigate the hourly climate characteristics of precipitation in the downstream section of the Yangtze River waterway. Our study reveals that September is the month with the strongest increase in monthly precipitation, and there is a slight weakening trend in the cold season (December to January of the following year) based on both GSMaP and CMORPH_ADJ datasets. Furthermore, in addition to the significant characteristics of the Meiyu season, there were precipitation events in the entire section in August early and late, September mid and late, October early and late, and November early and late, as shown in multi-year hourly average scale data. Regarding precipitation intensity, our analysis indicates that the GSMaP data showed an increase in the number of hours of light rain, mainly concentrated in the Jiangyin to Yangzhong navigation section. In CMORPH_ADJ, an increasing trend in the number of hours occurred mainly in September, with an increase of 0.6 h/yr, while in other periods, it showed a decreasing trend. The GSMaP data also reflect an increasing trend (1 h/yr) in the number of hours of moderate rain in September. Moreover, the number of hours of rain above moderate rain mainly occurs from mid-May to late August, with a slight increasing trend in recent years, significantly increasing the cost of summer shipping. In summary, our study provides detailed insights into the hourly climate characteristics of precipitation in the downstream section of the Yangtze River waterway. Our findings can be useful for improving the safety of shipping and reducing transportation costs on this important waterway.