Fire numbers, burned areas and return intervals in each large scale forest type with average patch area of 500?km 2 in Heilongjiang Province during the period of 1980 to 1999 were obtained by overlapping the ignition ...Fire numbers, burned areas and return intervals in each large scale forest type with average patch area of 500?km 2 in Heilongjiang Province during the period of 1980 to 1999 were obtained by overlapping the ignition points and areas of 1482 forest fires with the Province’s forest type maps in the same period by means of GIS software ARC/INFO. Analysis on the data indicated that the effects of the forest types on fire occurrence and burned areas in the Province were not significant, thus it was not necessary to take forest types into consideration when forest fire hazard was rated on a large scale. Years long human fire suppression activities increased fire return intervals in the region. Comparison was also made on the effects of forest types on fires at various scales.展开更多
本文根据不同类型云影响地面短波辐射的差异,提出利用地面短波总辐射变化检测识别淡积云以及计算淡积云水平尺度的方法,并对该算法进行误差分析,统计内蒙古草原地区夏季淡积云的水平尺度及其辐射强迫。结果表明:淡积云检测方法能比较好...本文根据不同类型云影响地面短波辐射的差异,提出利用地面短波总辐射变化检测识别淡积云以及计算淡积云水平尺度的方法,并对该算法进行误差分析,统计内蒙古草原地区夏季淡积云的水平尺度及其辐射强迫。结果表明:淡积云检测方法能比较好地识别、筛选出淡积云天。淡积云水平尺度和淡积云所在高度的风速成正比,风速测量的准确性直接影响淡积云水平尺度估算准确性;淡积云水平与垂直尺度比对计算淡积云水平尺度影响最大;云移动经过遮挡太阳直射辐射的时段内,太阳天顶角变化的影响可以忽略不计。内蒙古草原地区夏季淡积云短波辐射强迫小时平均为-134.1 W m-2,水平尺度平均值为1129 m,水平尺度的概率密度呈幂指数分布。展开更多
文摘Fire numbers, burned areas and return intervals in each large scale forest type with average patch area of 500?km 2 in Heilongjiang Province during the period of 1980 to 1999 were obtained by overlapping the ignition points and areas of 1482 forest fires with the Province’s forest type maps in the same period by means of GIS software ARC/INFO. Analysis on the data indicated that the effects of the forest types on fire occurrence and burned areas in the Province were not significant, thus it was not necessary to take forest types into consideration when forest fire hazard was rated on a large scale. Years long human fire suppression activities increased fire return intervals in the region. Comparison was also made on the effects of forest types on fires at various scales.
文摘本文根据不同类型云影响地面短波辐射的差异,提出利用地面短波总辐射变化检测识别淡积云以及计算淡积云水平尺度的方法,并对该算法进行误差分析,统计内蒙古草原地区夏季淡积云的水平尺度及其辐射强迫。结果表明:淡积云检测方法能比较好地识别、筛选出淡积云天。淡积云水平尺度和淡积云所在高度的风速成正比,风速测量的准确性直接影响淡积云水平尺度估算准确性;淡积云水平与垂直尺度比对计算淡积云水平尺度影响最大;云移动经过遮挡太阳直射辐射的时段内,太阳天顶角变化的影响可以忽略不计。内蒙古草原地区夏季淡积云短波辐射强迫小时平均为-134.1 W m-2,水平尺度平均值为1129 m,水平尺度的概率密度呈幂指数分布。
