| The extreme precipitation event induced by the tropical cyclone is one of the most common form of disasters,it poses a great threat to human life and property safety.Therefore,studying the changes of tropical cyclone precipitation can help to understanding its activity rules and improving the forecast skills of the tropical cyclone,and it can reducing the impact of tropical cyclone has great implications,especially under the changing climate.This paper investigates the global tropical cyclone precipitation characteristics from 1998 to 2016 by using the TRMM?Tropical Rainfall Measuring Mission?satellite 3B42 v7 product and IBTrACS?International Best Track Archive for Climate Stewardship?dataset.It is found that there are 81 tropical cyclones generated each year on Earth,mainly in the western North Pacific,the eastern North Pacific,the North Atlantic,the South Indian Ocean,the South Pacific,and the North Indian Ocean.The annual average global Power Dissipation Index?PDI?of tropical cyclones is 1.53×1012 m3 s-2,and the annual average PDI of tropical cyclones in the western North Pacific is 5.05×1011 m3 s-2,accounting for about one-third of the total global PDI.And this work revealed that tropical cyclone PDI in the western North Pacific has a significant regime shift around 1998,and this change was affected by the 1997/98 climate change.During 1998-2016,tropical cyclone PDI increased significantly.The increase trend is mainly affected by the increase of the average intensity of tropical cyclone.Meanwhile,ENSO and PDO both have strong influences on the tropical cyclones over the western North Pacific,the impacts from ENSO is mainly reflected in the interannual scale,while PDO mainly regulates the quasi-decadal scale oscillations of PDI.This study found that there has the largest tropical cyclone precipitation in the Western North Pacific region,mainly concentrated in Taiwan Island,the Philippine Islands,and their adjacent regions,the maximum precipitation is about 500600 mm accounting for 2030%of the total precipitation in this region.However,in the west of Mexico region,the tropical cyclone precipitation concentration are relatively small,but their account for about 40%of the total annual precipitation.In most other ocean basins,the annual average tropical cyclone precipitation accounts for about 1020%of the total annual precipitation.There are also large differences in the spatial distribution of tropical cyclone precipitation with different categories.In the variation of seasonal scale,the tropical cyclone precipitation is the largest in January-March over the Southern Hemisphere,and it is mainly concentrated in July-October over the Northern Hemisphere.By analyzing the trends of the rainfall rate of the tropical cyclone,it is found that the global tropical cyclone rainfall rate has a significant increasing trend from 1998 to 2016,and the increase rate is 0.20 mm h-1 per decade,which is increased by approximately 16.55%in2016 compared with 1998.Globally,the increase rates of precipitation intensity of TSs?Tropical Storms?and CAT 12?Category 1-2?were 0.22 mm h-1 and 0.19 mm h-1 per decade,respectively,while the trend of CAT 35?Category 3-5?was not significant.The instantaneous precipitation of global tropical cyclone decreased slightly?not significant?,while it decreases significantly in the Northern Hemisphere.The instantaneous precipitation reduction rate of CAT 35 in the Northwest Pacific is the largest,about-16.58×103 m3s-1 per year,which is about 46.26%lower in 2016 than 1998.And this work reveals that there is,globally,no obvious trends in tropical cyclone cumulative precipitation,but it is also increasing in the CAT 35 over the Western North Pacific area.Under the warming climate,the rainfall rate of the inner rain-bands of global tropical cyclone has a decreasing rate of 0.59 mm h-1 per decade,21%lower in 2016 than that of1998,and this trend is mainly caused by the increase of atmospheric stability,which results in the weakening of the convective precipitation rate in the tropical cyclone inner rain-bands region.While,there has a 0.25 mm h-1 per decade rate in the outer rain-bands of the tropical cyclone,which is an increase of 24%in 2016 compared with 1998,and the precipitation rate of the outer rain-bands is sensitive to the increased environmental water vapour.These trends of inner and outer rain-bands are basically reflected in all tropical cyclone in different categories and ocean basins.We also find that the instantaneous precipitation of the inner and outer rain-bands decreased during 19982016 period,and the decreasing trends in the inner rain-bands are more obvious;while,the cumulative precipitation of the inner and outer rain-bands of the tropical cyclone is not significant. |
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