共查询到20条相似文献，搜索用时 62 毫秒
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通过分析西北地区气候生产力与玉米产量的关系、土壤水分与降水量以及土壤水分与降水量和土壤初始含水量之和的关系表明:西北地区降水气候生产力与玉米产量、土壤水分与降水量和土壤初始含水量之和有着显著的相关性。在此基础上，利用玉米生长季内的降水量和播种期的土壤水分含量对Miami降水模型进行了改进，应用改进后的Miami降水模型开展以月为时间步长的玉米产量动态趋势预报，具有较为理想的业务服务效果。同时，利用此方法评价西北地区降水对玉米生长发育和产量形成的影响也非常适用。但是，由于此方法没有考虑灌溉水的作用，故不适用于灌溉农区。 相似文献
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一、引言我县1200—1500米的高山区,粮食主要以玉米为主.本文队分析1961年以来制约我县玉米产量的主要气候障碍入手,提出高山地区玉米增产的主要措施.二、影响我县玉米产量的主要气候因素及玉米生育期对积温的要求影响我县玉米产量的主要气候因素如表1所示. 相似文献
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气象因子对白城地区玉米产量的影响 总被引：1，自引：0，他引：1
本文是利用玉米的气候产量与玉米生育期间的积温、土壤重量含水率，建立了玉米气候产量和气象因子之间的回归模式，通过此模式可以计算出玉米产量的预报值。其结果与生产实践基本相符，具有比较好的实用性，可用于生产服务。 相似文献
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利用卫星资料和实时天气资料预测玉米产量 总被引：1，自引：0，他引：1
在作物收获之前进行大范围作物状况评价，对于提前估测产量是非常关键的。卫星和天气资料为近实时的作物监测提供了条件。研究的目的就是利用这些信息建立作物产量业务评估系统，在占全美国玉米产量 ６０％ 的玉米带，对预测 ４２ 个作物报告区的玉米生产进行评估。收集了１９８５～１９９２ 年共８ 年的卫星、气候和农业资料，建立了每个作物报告区标准化玉米产量预测模式，其自变量包括：卫星资料┐植被状况指数，气候资料┐作物水分指数。该模式大约解释了被观测到的标准化产量变化的３／４，对其估产准确性和时效性亦进行了检验。将整个玉米带研究区域预测的玉米产量与美国农业部在玉米收获后几个月的统计结果相比较，发现８ 个生长季的预测误差低于１０％ 。此外，该预测可在玉米收获前 ２ 个月完成。该系统具有为人类经济活动提供及时的区域或全球农业生产信息的潜力。 相似文献
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本文根据1983年4月—1986年3月三年山区梯度观测资料，综合考虑山区光、热、水农业的气候资源匹配关系，建立不同山区、坡向、高度的作物气候生产力估算模式。模式中对山区温度、降水、日照等气象要素进行了修正。运用模式估算了不同山区、坡向、高度的水稻、玉米、冬小麦气候生产力。计算结果:亚热带东部丘陵山区单、双季稻、夏玉米气候生产力一般南坡大于北坡，西坡大于东坡；春玉米、冬小麦一般北坡大于南坡，东坡大于西坡。双季晚稻气候生产力大于双季早稻，夏玉米大于春玉米（神农架山区除外）。应该指出，目前高产典型水稻产量可达其气候生产力的60%以上，玉米和冬小麦仅达到30%—50%左右，表明山区农业气候资源可开发潜力很大。本文为合理开发山区气候资源、调整农业布局及提高单位面积产量提供了定量的科学依据。 相似文献
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Going to the Extremes 总被引：8，自引：1，他引：8
Claudia Tebaldi Katharinec Hayhoe Julie M. Arblaster Gerald A. Meehl 《Climatic change》2006,79(3-4):185-211
Projections of changes in climate extremes are critical to assessing the potential impacts of climate change on human and
natural systems. Modeling advances now provide the opportunity of utilizing global general circulation models (GCMs) for projections
of extreme temperature and precipitation indicators. We analyze historical and future simulations of ten such indicators as
derived from an ensemble of 9 GCMs contributing to the Fourth Assessment Report of the Intergovernmental Panel on Climate
Change (IPCC-AR4), under a range of emissions scenarios. Our focus is on the consensus from the GCM ensemble, in terms of
direction and significance of the changes, at the global average and geographical scale. The climate extremes described by
the ten indices range from heat-wave frequency to frost-day occurrence, from dry-spell length to heavy rainfall amounts. Historical
trends generally agree with previous observational studies, providing a basic sense of reliability for the GCM simulations.
Individual model projections for the 21st century across the three scenarios examined are in agreement in showing greater
temperature extremes consistent with a warmer climate. For any specific temperature index, minor differences appear in the
spatial distribution of the changes across models and across scenarios, while substantial differences appear in the relative
magnitude of the trends under different emissions rates. Depictions of a wetter world and greater precipitation intensity
emerge unequivocally in the global averages of most of the precipitation indices. However, consensus and significance are
less strong when regional patterns are considered. This analysis provides a first overview of projected changes in climate
extremes from the IPCC-AR4 model ensemble, and has significant implications with regard to climate projections for impact
assessments.
An erratum to this article is available at .
An erratum to this article can be found at 相似文献
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雷击电磁干扰对以计算机为主的电子信息系统的影响巨大,本文分析了雷电侵害计算机网络的途径,针对雷击电磁干扰侵害计算机网络的几种途径,主要从机房及布线的要求、等电位连接、瞬态过电压保护器的选择、接地等几方面进行雷击电磁干扰的防护设计。 相似文献
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１引言气象业务网络有一个特点，就是处理的对象大多数是实时资料。因而很多计算机是不需要保留历史资料的（例如：PCVSAT单收站、MICAPS平台等），并且保证业务运行的系统软件和应用软件是固定的。基于这一点，为网络中处理实时资料的计算机做一个永久备份。当这些计算机出现不容易排除的故障时，就可以利用这些备份在几分钟之内恢复正常运行。下面介绍利用GHOST和DiskGenius两个软件来完成这工作的方法。２分区在分区的时候，为GHOST克隆出的映像文件划分一个独立的分区。如果使用的是WINDOWS９８操作系统，这个分区大小为５… 相似文献
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介绍采用W inRoute F irewall软件实现市、县局用户共享上网的方法,使市县局用户既能共享网络资源,又能有效地保障网络安全。 相似文献
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Godefroy Grosjean Sabine Fuss Nicolas Koch Benjamin L. Bodirsky Stéphane De Cara William Acworth 《Climate Policy》2018,18(2):151-169
Although agriculture could contribute substantially to European emission reductions, its mitigation potential lies untapped and dormant. Market-based instruments could be pivotal in incentivizing cost-effective abatement. However, sector specificities in transaction costs, leakage risks and distributional impacts impede its implementation. The significance of such barriers critically hinges on the dimensions of policy design. This article synthesizes the work on emissions pricing in agriculture together with the literature on the design of market-based instruments. To structure the discussion, an options space is suggested to map policy options, focusing on three key dimensions of policy design. More specifically, it examines the role of policy coverage, instruments and transfers to farmers in overcoming the barriers. First, the results show that a significant proportion of agricultural emissions and mitigation potential could be covered by a policy targeting large farms and few emission sources, thereby reducing transaction costs. Second, whether an instrument is voluntary or mandatory influences distributional outcomes and leakage. Voluntary instruments can mitigate distributional concerns and leakage risks but can lead to subsidy lock-in and carbon price distortion. Third, the impact on transfers resulting from the interaction of the Common Agricultural Policy (CAP) with emissions pricing will play a key role in shaping political feasibility and has so far been underappreciated.
POLICY RELEVANCE
Following the 2015 Paris Agreement, European climate policy is at a crossroads. Achieving cost-effectively the 2030 and 2050 European targets requires all sectors to reduce their emissions. Yet, the cornerstone of European climate policy, the European Union Emissions Trading System (EU ETS), covers only about half of European emissions. Major sectors have been so far largely exempted from carbon pricing, in particular transport and agriculture. While transport has been increasingly under the spotlight as a possible candidate for an EU ETS sectoral expansion, policy discussions on pricing agricultural emissions have been virtually absent. This article attempts to fill this gap by investigating options for market-based instruments to reduce agricultural emissions while taking barriers to implementation into account. 相似文献
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Framing the way to relate climate extremes to climate change 总被引：3，自引：1，他引：2
Kevin E. Trenberth 《Climatic change》2012,115(2):283-290
The atmospheric and ocean environment has changed from human activities in ways that affect storms and extreme climate events. The main way climate change is perceived is through changes in extremes because those are outside the bounds of previous weather. The average anthropogenic climate change effect is not negligible, but nor is it large, although a small shift in the mean can lead to very large percentage changes in extremes. Anthropogenic global warming inherently has decadal time scales and can be readily masked by natural variability on short time scales. To the extent that interactions are linear, even places that feature below normal temperatures are still warmer than they otherwise would be. It is when natural variability and climate change develop in the same direction that records get broken. For instance, the rapid transition from El Ni?o prior to May 2010 to La Ni?a by July 2010 along with global warming contributed to the record high sea surface temperatures in the tropical Indian and Atlantic Oceans and in close proximity to places where record flooding subsequently occurred. A commentary is provided on recent climate extremes. The answer to the oft-asked question of whether an event is caused by climate change is that it is the wrong question. All weather events are affected by climate change because the environment in which they occur is warmer and moister than it used to be. 相似文献