孟加拉国海岸带近30a红树林变化遥感分析

孟加拉国是21世纪海上丝绸之路沿线重要的支点国家，海岸带广泛分布有红树林，其西南部的松达班地区尤其典型。本研究基于1990、1996、2000、2005、2010和2016年6个时期Landsat TM/OLI中等分辨率卫星遥感影像数据，开展了基于SVM方法的孟加拉国海岸带红树林遥感监测，并应用8 m空间分辨率的GF1-PMS1卫星遥感数据进行结果检验，给出了6个时期孟加拉国海岸带红树林空间分布状况，分析了红树林30 a间的演变趋势。结果表明:1）近30 a孟加拉国海岸带红树林面积整体上呈现缓慢减少的趋势，1990年面积为468218.932 hm2，至2016年红树林面积共减少17077.898 hm2；2）海岸带红树林空间上呈东部和西部减少，中部增加的态势，近30 a间东部吉大港专区红树林面积减少了45.7%，西部库尔纳专区红树林减少了2632.007 hm2，但仅占总面积的0.64%，中部巴里萨尔专区红树林面积增加3108.604 hm2；3）东部吉大港专区红树林面积减少区域主要位于诺阿卡利附近沿岸和佐拉尔甘杰沿岸，主要减少的原因是虾养殖池的建立；西部库尔纳专区红树林减少区域主要分布在松达班地区河口、沿岸附近，主要减少的原因是虾养殖池的建立和人类活动将红树林转换为其他类用地；中部巴里萨尔专区红树林面积增加区域主要分布在戈拉吉博群岛周边，主要增加的原因是人工种植红树林和红树林的自然增长。

Change analysis of mangrove in Bangladesh coastal zone based on remote sensing in the recent 30 years

Bangladesh is an important joint along the Silk Road in the 21st century.The mangroves are widely distributed in the coastal zone, especially in the Sundarbans in the southwest.This study is based on the data of remote sensing images in 1990, 1996, 2000, 2005, 2010 and 2016, six period Landsat TM/OLI moderate resolution satellite was carried out based on the SVM method of Bangladesh coastal mangrove remote monitoring, applying 8 m spatial resolution GF1-PMS1 satellite remote sensing data in the test, given 6 times in Bangladesh coastal mangrove space the distribution, analyzes the evolution trend of mangrove 30 a.The results showed that:1) in the past 30 years, the area of mangrove forest in coastal area of Bangladesh showed a decreasing trend as a whole, with an area of 468218.932 hm2 in 1990 and 17077.898 hm2 in 2016; 2) the western part of the reduction, the central increase in the situation, nearly 30 a Eastern Chittagong area mangrove area decreased by 45.7%, the western Khulna area mangrove reduced by 2632.007 hm2, but only 0.64% of the total area, the central Barisal area Mangrove area increased by 3108.604 hm2; 3) reduced area of mangrove area in the eastern Chittagong area is mainly located along the coast of Noakhali and along the zorarganj, mainly due to the establishment of shrimp ponds; the area of the subtropical forest is mainly distributed in the estuary of the Sundarbans, near the coast, the main reason for the reduction is the establishment of the shrimp and the human activities convert the mangrove forest into other types land; the central mangrove area distributed in the Barisal is mainly increase, the main reason is the natural growth and plants.