Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wetness grades. Further, a drought area index was proposed to study c...Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wetness grades. Further, a drought area index was proposed to study changes in drought severity in northern China. The results revealed that the different severity of droughts all showed expanding trends in northern China's main agricultural area. Moreover, the area coverage of droughts in different seasons and different regions displayed different trends.展开更多
Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss...Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China.展开更多
近年来随着全球变暖,干旱事件的增加对植被的光合作用产生更加重要的影响,同时也严重影响了陆地生态系统的平衡。本文基于标准化降水蒸散指数(SPEI base v.2.7)和总初级生产力数据集(GOSIF GPP)研究了干旱对中国北方草原GPP的累积和时...近年来随着全球变暖,干旱事件的增加对植被的光合作用产生更加重要的影响,同时也严重影响了陆地生态系统的平衡。本文基于标准化降水蒸散指数(SPEI base v.2.7)和总初级生产力数据集(GOSIF GPP)研究了干旱对中国北方草原GPP的累积和时滞效应,利用Sen’s斜率、Mann-Kendall(MK)趋势检验、Mann-Kendall突变检验研究了GPP和SPEI在研究期内的时空变化,利用Pearson相关分析方法探究了干旱对北方草原GPP的累积和时滞效应。结果表明:(1)2001—2020年期间北方草原多年平均GPP呈现东北地区高、西南地区低的空间分布格局,多年平均SPEI呈现东北地区低、西南地区高的空间分布格局,且SPEI和GPP的年平均值都随时间变化呈现上升趋势。(2)干旱对北方草原84.99%的区域有累积效应,最长累积时间尺度主要集中在3~4个月,覆盖北方草原的39.82%;干旱对北方草原63.11%的区域有滞后效应,且主要发生在7个月,覆盖北方草原的19.73%。(3)通过对比不同水分条件下二者的变化趋势,发现干旱对草原GPP的累积效应强于时滞效应。展开更多
北方地区是中国主要的玉米种植区，在中国玉米总产和播种面积中占有较大比例，同时也是中国易发生干旱的地区，北方地区干旱常态化严重制约着该地区玉米的稳定发展。该文基于北方地区14个省（市、自治区）217个气象台站1961－2010年的...北方地区是中国主要的玉米种植区，在中国玉米总产和播种面积中占有较大比例，同时也是中国易发生干旱的地区，北方地区干旱常态化严重制约着该地区玉米的稳定发展。该文基于北方地区14个省（市、自治区）217个气象台站1961－2010年的逐日气象数据以及作物、土壤和田间管理资料，依据春玉米生长季内降水量并以100 mm为间隔将全区划分为6个区域（Ⅰ～Ⅵ），选取作物水分亏缺指数为农业干旱指标，基于验证后的农业生产系统模型（agricultural production systems simulator，APSIM），明确了各生育阶段不同等级干旱对春玉米产量的影响。研究结果表明，北方地区干旱造成春玉米减产率在空间上呈由西向东下降趋势，降水的空间分布直接导致了灾损程度在各区的差异，其中西部灌溉绿洲农业区雨养种植春玉米干旱风险非常大，需大力发展节水灌溉，而东部雨养农业区自然降水已基本满足春玉米生长发育需要，干旱对春玉米产量影响较小，在模拟过程中很难准确的反映出旱级对产量造成的差异影响。春玉米在拔节—抽雄阶段发生干旱会对产量造成比较严重的影响，该阶段4个等级干旱造成春玉米减产率的四分位区间分别为特旱（20.1%～33.6%）、重旱（12.0%～20.3%）、中旱（6.3%～15.2%）、轻旱（4.7%～11.6%）。展开更多
基金The Project of the Ministry of Science and Technology,No.2001BA611B-01National Meteorological Center,ZK2002C-04
文摘Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wetness grades. Further, a drought area index was proposed to study changes in drought severity in northern China. The results revealed that the different severity of droughts all showed expanding trends in northern China's main agricultural area. Moreover, the area coverage of droughts in different seasons and different regions displayed different trends.
基金supported by the National Basic Research Program of China (No. 2009CB421300): "The Processes of Oasifica-tion-Desertification and their Responding to Human Activities & Climatic Change and their Regulation in the Arid Region of China"
文摘Aeolian desertification has rapidly developed in the past 50 years in Northern China,covered an area of 0.386 million km2 by 2000,affected nearly 170 million population,and caused the direct and indirect economic loss of about $6.75(U.S.dollar) billion per year.Here we present several lines of evidence to demonstrate that human activities guided by policy shifts have been a major force to drive aeolian desertification via changes in land-use patterns and intensity.It is suggested that the desertification can be curbed or even reversed by adopting prevention and control measures with ecologically sound land-use practices in China.
文摘近年来随着全球变暖,干旱事件的增加对植被的光合作用产生更加重要的影响,同时也严重影响了陆地生态系统的平衡。本文基于标准化降水蒸散指数(SPEI base v.2.7)和总初级生产力数据集(GOSIF GPP)研究了干旱对中国北方草原GPP的累积和时滞效应,利用Sen’s斜率、Mann-Kendall(MK)趋势检验、Mann-Kendall突变检验研究了GPP和SPEI在研究期内的时空变化,利用Pearson相关分析方法探究了干旱对北方草原GPP的累积和时滞效应。结果表明:(1)2001—2020年期间北方草原多年平均GPP呈现东北地区高、西南地区低的空间分布格局,多年平均SPEI呈现东北地区低、西南地区高的空间分布格局,且SPEI和GPP的年平均值都随时间变化呈现上升趋势。(2)干旱对北方草原84.99%的区域有累积效应,最长累积时间尺度主要集中在3~4个月,覆盖北方草原的39.82%;干旱对北方草原63.11%的区域有滞后效应,且主要发生在7个月,覆盖北方草原的19.73%。(3)通过对比不同水分条件下二者的变化趋势,发现干旱对草原GPP的累积效应强于时滞效应。
文摘北方地区是中国主要的玉米种植区，在中国玉米总产和播种面积中占有较大比例，同时也是中国易发生干旱的地区，北方地区干旱常态化严重制约着该地区玉米的稳定发展。该文基于北方地区14个省（市、自治区）217个气象台站1961－2010年的逐日气象数据以及作物、土壤和田间管理资料，依据春玉米生长季内降水量并以100 mm为间隔将全区划分为6个区域（Ⅰ～Ⅵ），选取作物水分亏缺指数为农业干旱指标，基于验证后的农业生产系统模型（agricultural production systems simulator，APSIM），明确了各生育阶段不同等级干旱对春玉米产量的影响。研究结果表明，北方地区干旱造成春玉米减产率在空间上呈由西向东下降趋势，降水的空间分布直接导致了灾损程度在各区的差异，其中西部灌溉绿洲农业区雨养种植春玉米干旱风险非常大，需大力发展节水灌溉，而东部雨养农业区自然降水已基本满足春玉米生长发育需要，干旱对春玉米产量影响较小，在模拟过程中很难准确的反映出旱级对产量造成的差异影响。春玉米在拔节—抽雄阶段发生干旱会对产量造成比较严重的影响，该阶段4个等级干旱造成春玉米减产率的四分位区间分别为特旱（20.1%～33.6%）、重旱（12.0%～20.3%）、中旱（6.3%～15.2%）、轻旱（4.7%～11.6%）。
