In this study, we investigate the spatiotemporal characteristics of drought in India and its impact on agriculture during the summer season (April-September). In the analysis, we use Standardized Precipitation Evapo...In this study, we investigate the spatiotemporal characteristics of drought in India and its impact on agriculture during the summer season (April-September). In the analysis, we use Standardized Precipitation Evapotranspiration Index (SPEI) datasets between 1982 and 2012 at the six-monthly timescale. Based on the criterion SPEI 〈 -1, we obtain a map of the number of occurrences of drought and find that the humid subtropical Upper Middle Gangetic Plain (UMGP) region is highly drought-prone, with an occurrence frequency of 40%-45%. This UMGP region contributes at least 18%-20% of India's annual cereal production. Not only the probability of drought, but the UMGP region has become increasingly drought-prone in recent decades. Moreover, cereal production in the UMGP region has experienced a gradual declining trend from 2000 onwards, which is consistent with the increase in drought-affected areas from 20%-25% to 50%-60%, before and after 2000, respectively. A higher correlation coefficient (-0.69) between the cereal production changes and drought-affected areas confirms that at least 50% of the agricultural (cereal) losses are associated with drought. While analyzing the individual impact of precipitation and surface temperature on SPEI at 6 month timescale [SPEI (6)] we find that, in the UMGP region, surface temperature plays the primary role in the lowering of the SPEI. The linkage is further confirmed by correlation analysis between SPEI (6) and surface temperature, which exhibits strong negative values in the UMGP region. Higher temperatures may have caused more evaporation and drying, which therefore increased the area affected by drought in recent decades.展开更多
The Greater Hinggan Forest was the world’s largest stand of evergreens,along the Black Dragon River(also known as Amur),which forms the border between Chinese Manchuria and Soviet Siberia.Black Dragon fire ranks as o...The Greater Hinggan Forest was the world’s largest stand of evergreens,along the Black Dragon River(also known as Amur),which forms the border between Chinese Manchuria and Soviet Siberia.Black Dragon fire ranks as one of the worst environmental disasters of the 20th century and it burned about 18 million acres of conifer forest.In the 2nd week of May,1987,we observe more than 10K rise in brightness temperature over a wide region in the China-Russia border.The weekly mean NDVI data shows the changes in greenness after the forest fire broke out.The NDVI value is positive with persistent greenness and vegetation in the Amur River valley,but from the 2nd week of May onwards the reddish patch appears to spread over the entire region,indicates the burned areas.In addition,we observe the impact of Black Dragon forest fire on tropospheric ozone concentration,aerosol index away from the location over North Pacific Ocean.A clear increase in atmospheric pollutants can be noticed after the forest fire event and the long range transports are confirmed with 72 hours NOAA HYSPLIT forward trajectory analysis.展开更多
随着城市化的发展和人均收入的提高,中国居民对猪肉的需求日益增长。猪肉生产耗水量大,其包括饲料作物生长所消耗的水,也包括生猪生产过程所消耗的水。本文从生猪生产的角度计算了2001-2012年生猪生产耗水,结果表明生猪生产水足迹由200...随着城市化的发展和人均收入的提高,中国居民对猪肉的需求日益增长。猪肉生产耗水量大,其包括饲料作物生长所消耗的水,也包括生猪生产过程所消耗的水。本文从生猪生产的角度计算了2001-2012年生猪生产耗水,结果表明生猪生产水足迹由2001年的3.39m^3/kg下降到2012年的3.31m^3/kg,但生猪生产耗水却从2001年的1910亿m^3上升到2012年的2650亿m^3,增长了38.95%。运用对数平均迪氏指数法(Logarithmic Mean Divisia Index,LMDI)对影响生猪生产耗水的因素进行了分析。在影响生猪生产耗水的3个因素中,人口的增长和猪肉消费量的增加导致生猪生产耗水的增加,而生猪生产水足迹的降低则会降低生猪生产耗水,三者中,猪肉消费量对生猪生产耗水的贡献最大。同时,农场耗水所占比例不断增加。本研究第一次揭示了长时间尺度,中国大、中、小规模化及散养养殖情况下,生猪生产水足迹的变化以及生产耗水。这有助于处理中国生猪产业的快速发展和耗水量不断增加的关系,促进生猪产业的可持续发展。展开更多
基金supported by the National Basic Research Development Program of China(Grant No.2015CB953602)National Science Foundation of China(Grant Nos.41271542 and 41661144006)a CAS-TWAS President’s Fellowship,2013
文摘In this study, we investigate the spatiotemporal characteristics of drought in India and its impact on agriculture during the summer season (April-September). In the analysis, we use Standardized Precipitation Evapotranspiration Index (SPEI) datasets between 1982 and 2012 at the six-monthly timescale. Based on the criterion SPEI 〈 -1, we obtain a map of the number of occurrences of drought and find that the humid subtropical Upper Middle Gangetic Plain (UMGP) region is highly drought-prone, with an occurrence frequency of 40%-45%. This UMGP region contributes at least 18%-20% of India's annual cereal production. Not only the probability of drought, but the UMGP region has become increasingly drought-prone in recent decades. Moreover, cereal production in the UMGP region has experienced a gradual declining trend from 2000 onwards, which is consistent with the increase in drought-affected areas from 20%-25% to 50%-60%, before and after 2000, respectively. A higher correlation coefficient (-0.69) between the cereal production changes and drought-affected areas confirms that at least 50% of the agricultural (cereal) losses are associated with drought. While analyzing the individual impact of precipitation and surface temperature on SPEI at 6 month timescale [SPEI (6)] we find that, in the UMGP region, surface temperature plays the primary role in the lowering of the SPEI. The linkage is further confirmed by correlation analysis between SPEI (6) and surface temperature, which exhibits strong negative values in the UMGP region. Higher temperatures may have caused more evaporation and drying, which therefore increased the area affected by drought in recent decades.
基金supported by National Natural Science Foundation of China International Cooperation and Exchange Program(4181101072).
文摘The Greater Hinggan Forest was the world’s largest stand of evergreens,along the Black Dragon River(also known as Amur),which forms the border between Chinese Manchuria and Soviet Siberia.Black Dragon fire ranks as one of the worst environmental disasters of the 20th century and it burned about 18 million acres of conifer forest.In the 2nd week of May,1987,we observe more than 10K rise in brightness temperature over a wide region in the China-Russia border.The weekly mean NDVI data shows the changes in greenness after the forest fire broke out.The NDVI value is positive with persistent greenness and vegetation in the Amur River valley,but from the 2nd week of May onwards the reddish patch appears to spread over the entire region,indicates the burned areas.In addition,we observe the impact of Black Dragon forest fire on tropospheric ozone concentration,aerosol index away from the location over North Pacific Ocean.A clear increase in atmospheric pollutants can be noticed after the forest fire event and the long range transports are confirmed with 72 hours NOAA HYSPLIT forward trajectory analysis.
文摘随着城市化的发展和人均收入的提高,中国居民对猪肉的需求日益增长。猪肉生产耗水量大,其包括饲料作物生长所消耗的水,也包括生猪生产过程所消耗的水。本文从生猪生产的角度计算了2001-2012年生猪生产耗水,结果表明生猪生产水足迹由2001年的3.39m^3/kg下降到2012年的3.31m^3/kg,但生猪生产耗水却从2001年的1910亿m^3上升到2012年的2650亿m^3,增长了38.95%。运用对数平均迪氏指数法(Logarithmic Mean Divisia Index,LMDI)对影响生猪生产耗水的因素进行了分析。在影响生猪生产耗水的3个因素中,人口的增长和猪肉消费量的增加导致生猪生产耗水的增加,而生猪生产水足迹的降低则会降低生猪生产耗水,三者中,猪肉消费量对生猪生产耗水的贡献最大。同时,农场耗水所占比例不断增加。本研究第一次揭示了长时间尺度,中国大、中、小规模化及散养养殖情况下,生猪生产水足迹的变化以及生产耗水。这有助于处理中国生猪产业的快速发展和耗水量不断增加的关系,促进生猪产业的可持续发展。