TROPICAL GEOGRAPHY ›› 2015, Vol. 35 ›› Issue (3): 315-323.

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Empirical Curves of Rubber Tree Fragility to Tropical Cyclone Wind in Hainan

WU Xiaoning,FANG Weihua,LIN Wei,YE Yanting   

  1. (Academy of Disaster Reduction and Emergency Management,Ministry of Civil Affairs & Ministry of Education,Beijing Normal University//Key Laboratory of Environmental Change and Natural Disaster,Ministry of Education of China,Beijing Normal University,Beijing 100875,China)
  • Online:2015-06-05 Published:2015-06-05

Abstract:

Hainan Island, located in the tropical and sub-tropical areas of South China, has been the largest base for rubber tree (Hevea brasiliensis) plantation and rubber production in China. Rubber trees are fragile to high wind, and therefore they have been suffering from the frequent tropical cyclones (TC) impacting Hainan. The quantitative evaluation of rubber tree fragility to TC wind is of vital importance to risk management, especially for catastrophe risk modeling. In this paper, firstly, the footprints of 16 TCs (1971-2010) are simulated at 1km grids with parametric TC windfield models considering both topographic and land use roughness effects. Then, the damage ratios of 2 rubber tree age groups (mature and young) from 5 damage types (overthrown, trunk snapped below 2 m, trunk snapped above 2 m, half-overthrown, and sheared) at farm scale are calculated based on rubber tree historical exposure and damage data. Thirdly, 3s peak gust wind (V3s) is selected to reflect wind hazard intensity, and the fragility curves for the 2 age groups and their 5 damage types are estimated through Beaufort Scale 6~14. In addition, the uncertainty of damage ratios is also quantitatively expressed. It is found that mature (young) rubber tree damage begins at Beaufort Scale 6 (7) and then increases with the wind speed, leading to almost 70% (55%) total damage ratio at Beaufort Scale 14; mature trees demonstrate a higher fragility than young trees; the uncertainty of the 10 vulnerability curves varies with wind speed interval, tree age group, and damage type. Fragility curves developed in this study have been applied in a catastrophe risk model for designing a parametric wind insurance scheme on rubber tree TC disasters in Hainan Province.

Key words: rubber tree, fragility, tropical cyclone, Hainan