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71.
采用作物模型与数理统计相结合的方法,利用长期历史气象资料,以作物模型和地理信息系统技术为工具,系统分析了河南地区旱稻生育期水分盈亏情况。以模型模拟的雨养条件下实际蒸散量相对于潜在条件下的蒸散量(即需水量)的亏缺率,即水分亏缺指数,以雨养条件下产量相对于潜在产量的损失率(即灾损指数)作为产量灾损强度评价指标,从受旱程度和产量损失两个角度构建干旱风险评估模型,进行干旱风险评估。结果表明:河南省旱稻生育期集中在6—9月,水分亏缺最多的阶段为出苗—穗分化阶段,水分亏缺指数变化在0.50~0.60,其次是开花—成熟阶段和穗分化—开花阶段,水分亏缺指数变化在0.11~0.43;全生育期水分亏缺指数在0.36~0.50。出苗—穗分化阶段干旱发生的风险最大,其次是开花—成熟阶段,穗分化—开花阶段的最小。河南旱稻生育期干旱风险呈现为由东南向西北逐渐升高的分布,其中三门峡、济源西部一带风险最高,洛阳南部和南阳西北部一带最低,黄河以北大部地区和豫东、豫南地区风险居中。  相似文献   
72.
农业遥感研究应用进展与展望   总被引:22,自引:0,他引:22  
得益于中国自主遥感卫星、无人机遥感和物联网等技术的发展,中国农业遥感研究与应用在过去20年取得了显著进步,中国农业遥感信息获取呈现出天地网一体化的趋势;农业定量遥感在关键参数遥感反演技术方法与应用方面取得进展;作物面积、长势、产量、灾害遥感监测的理论与技术方法取得突破,农业遥感技术应用领域不断拓展。本文从农业遥感信息获取、农业定量遥感、农业灾害遥感、作物遥感识别与制图、作物长势遥感监测与产量预测、农业土地资源遥感等方面对中国农业遥感科研与应用进行了总结综述。  相似文献   
73.
变化环境下渭河流域水文干旱演变特征剖析   总被引:4,自引:0,他引:4       下载免费PDF全文
环境变化影响区域水资源的可持续开发利用,导致水文过程出现非平稳特征,需发展非平稳水文干旱评估方法。选取渭河流域为研究区,依据流域内2个水文站、62个雨量站和24个气象站1961-2013年数据,基于可变下渗容量模型定量分离气候变化和人类活动对径流衰减的贡献;采用标准化径流指数(Standardized Runoff Index, SRI)剖析水文干旱时空演变特征;提出多种SRI参数化方案,对比评定各方案表征非平稳干旱的合理性以及环境变化对干旱演变的影响作用。结果表明:自1991年以来渭河流域年径流量呈显著衰减趋势,人类活动是径流演变的主要因素,对咸阳和华县站径流量变化的贡献率分别为-66.7%和-71.0%;时变参数方案计算的干旱指数能合理重建历史水文干旱序列;人类活动是渭河流域1991年以来短历时水文干旱发生的主导因素,气候变化主要影响长历时旱涝的演变趋势。  相似文献   
74.
中国历史极端干旱研究进展   总被引:1,自引:0,他引:1       下载免费PDF全文
中国现有抗旱相关法规、规划、标准和制度等均是按常态干旱考虑的,几乎没有考虑大范围、长历时极端干旱的问题。一旦发生类似崇祯大旱和光绪大旱等极端干旱,将对中国经济社会产生深刻影响。从历史旱涝序列重建、极端干旱事件复原和重演3个方面论述了相关研究进展,发现重建方面缺乏重建方法对比研究、重建序列时空分辨率较低等,复原方面缺乏干旱灾害双重属性的考虑等,重演方面缺乏对抗旱减灾能力以及全球气候变化的考虑等。对未来研究重点和实践需求进行了展望,指出需在不同重建方法交叉检验、高时空分辨率旱涝序列重建、基于自然灾害双重属性的历史极端干旱事件复原、历史极端干旱事件定量化重演和干旱巨灾风险应对战略等方面取得突破性进展。  相似文献   
75.
At present, flash drought occurs globally and regionally and causes a lot of socio-economic loss in a very short time. Therefore, flash drought has been regarded as one of the hottest issues in drought research. However, flash drought monitoring, prediction and decision-making have encountered a lot of challenges due to its multiple driven factors and complex spatio-temporal process. Aiming at this problem, this paper focused on the agricultural land in China, and analyzed the spatio-temporal distribution of three kinds of flash droughts (i.e., precipitation-deficit, high-temperature, and composite flash droughts) from 1983 to 2015. We studied the occurrences, duration, spatial distribution, temporal distribution, and trend of all three kinds of flash droughts. Our results demonstrated that, the occurrences of flash drought agricultural land in China increased year by year, among which high-temperature flash drought increased dramatically; duration of flash droughts had different trends, but the variations were relatively smooth; Northeast China was identified as a vulnerable area of flash drought, indicating more flash drought events and longer duration; flash droughts in China were found to concentrate in spring (high-temperature drought) and summer seasons (precipitation-deficit drought). This study is helpful for building new flash drought monitoring method and system, and it is also valuable for flash drought preparedness on regional scale.  相似文献   
76.
The majority of emissions of nitrous oxide – a potent greenhouse gas (GHG) – are from agricultural sources, particularly nitrogen fertilizer applications. A growing focus on these emission sources has led to the development in the United States of GHG offset protocols that could enable payment to farmers for reducing fertilizer use or implementing other nitrogen management strategies. Despite the development of several protocols, the current regional scope is narrow, adoption by farmers is low, and policy implementation of protocols has a significant time lag. Here we utilize existing research and policy structures to propose an ‘umbrella’ approach for nitrogen management GHG emissions protocols that has the potential to streamline the policy implementation and acceptance of such protocols. We suggest that the umbrella protocol could set forth standard definitions common across multiple protocol options, and then modules could be further developed as scientific evidence advances. Modules could be developed for specific crops, regions, and practices. We identify a policy process that could facilitate this development in concert with emerging scientific research and conclude by acknowledging potential benefits and limitations of the approach.

Key policy insights

  • Agricultural greenhouse gas market options are growing, but are still underutilized

  • Streamlining protocol development through an umbrella process could enable quicker development of protocols across new crops, regions, and practices

  • Effective protocol development must not compromise best available science and should follow a rigorous pathway to ensure appropriate implementation

  相似文献   
77.
Strong and rapid greenhouse gas (GHG) emission reductions, far beyond those currently committed to, are required to meet the goals of the Paris Agreement. This allows no sector to maintain business as usual practices, while application of the precautionary principle requires avoiding a reliance on negative emission technologies. Animal to plant-sourced protein shifts offer substantial potential for GHG emission reductions. Unabated, the livestock sector could take between 37% and 49% of the GHG budget allowable under the 2°C and 1.5°C targets, respectively, by 2030. Inaction in the livestock sector would require substantial GHG reductions, far beyond what are planned or realistic, from other sectors. This outlook article outlines why animal to plant-sourced protein shifts should be taken up by the Conference of the Parties (COP), and how they could feature as part of countries’ mitigation commitments under their updated Nationally Determined Contributions (NDCs) to be adopted from 2020 onwards. The proposed framework includes an acknowledgment of ‘peak livestock’, followed by targets for large and rapid reductions in livestock numbers based on a combined ‘worst first’ and ‘best available food’ approach. Adequate support, including climate finance, is needed to facilitate countries in implementing animal to plant-sourced protein shifts.

Key policy insights

  • Given the livestock sector’s significant contribution to global GHG emissions and methane dominance, animal to plant protein shifts make a necessary contribution to meeting the Paris temperature goals and reducing warming in the short term, while providing a suite of co-benefits.

  • Without action, the livestock sector could take between 37% and 49% of the GHG budget allowable under the 2°C and 1.5°C targets, respectively, by 2030.

  • Failure to implement animal to plant protein shifts increases the risk of exceeding temperate goals; requires additional GHG reductions from other sectors; and increases reliance on negative emissions technologies.

  • COP 24 is an opportunity to bring animal to plant protein shifts to the climate mitigation table.

  • Revised NDCs from 2020 should include animal to plant protein shifts, starting with a declaration of ‘peak livestock’, followed by a ‘worst first’ replacement approach, guided by ‘best available food’.

  相似文献   
78.
基于辽宁省1114个国家级和区域级地面台站1961年以来的逐日气温和降水观测资料,利用距离平方反比法差值生成了1717个乡镇的气象资料序列,采用气象干旱综合监测指数统计分析了辽宁省2017年4—8月精细化到乡镇的气象干旱特征。结果表明:2017年辽宁省春夏季异常高温,同时降水异常偏少,致使气象干旱不断发展;干旱在4月5日前从中部和北部开始,4月末扩展到西部,5—6月再向东南发展,波及88%的乡镇,7月以来气象干旱程度开始减轻;气象干旱持续时间长的乡镇主要集中在中部和北部,最长持续时间153d;受气温偏高和降水过程的影响,中度以上气象干旱面积呈阶段性变化,且极端干旱的发展伴随高温时段。由于气象干旱不同于农业干旱,在开展为农服务时要因地制宜采取应对措施。  相似文献   
79.
利用气候观测数据分析表明,近60a来,百色出现了与全球气候变化背景一致的增暖变化,主要变化特征有:气温明显升高,年降水日数减少,冬季降水量增多,年日照时数减少;高温和干旱频率高,20世纪90年代以来暴雨日数偏多。与广西平均气候变化状况相比,百色的气候变化程度风险低于广西平均水平。预估到本世纪中期,百色气温仍将缓慢升高,干旱和强降水的强度可能加剧。建议科学规划,统筹协调,科学评估城市气候承载力,开展城市适应气候变化风险管理,提升生态气候环境监测及自然灾害预警应急能力,建设生态气候宜居城市。  相似文献   
80.
2016年5月15日清晨河西走廊东部发生区域性强霜冻天气,对农林业生产造成了2004年以来最为严重的灾害。本文利用实时MICAPS常规观测资料、物理量场和河西走廊东部区域内6个国家自动气象观测站和93个区域气象站观测资料,对这次冻害天气过程的天气学成因进行分析,在此基础上分析了霜冻对农业的影响。结果表明强冷空气爆发是造成冻害的直接原因;0 cm地面温度和气温≤0 ℃持续时间长,导致农林作物深度冻伤;前期气温偏高使得农林作物发育期提前,加之霜冻出现时间偏迟,农林作物抵抗冻害的能力明显下降,冻害影响加重;冻害发生后,温度急剧上升、湿度迅速减小,作物水分强烈蒸腾,作物细胞失去受损,导致受灾程度加重。  相似文献   
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