Influence on Rice Production in Japan from Cool and Hot Summers after Global Warming
Influence on Rice Production in Japan from Cool and Hot Summers after Global Warming
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DOI：
10.2480/agrmet.63.11
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发表时间：
2007
影响因子：
1.3
通讯作者：
T. Iizumi;Y. Hayashi;F. Kimura
中科院分区：
文献类型：
--
作者：
T. Iizumi;Y. Hayashi;F. Kimura
在目前的气候条件下，凉爽的夏季严重损害了日本的水稻产量。另一方面，在全球变暖后的气候中，由于开花期的热应力，极端炎热的夏季可能会减少产量。需要可靠的影响预测，以掌握生产变异的危害。然而，大气环流模式（GCM）产品的准确性限制阻碍了对特别极端年份的影响预测。本文提出了一种新的动态降尺度方法，该方法有助于从GCM产品中估计更高分辨率的气候，同时减少GCM偏差。偏差是指模拟值与观测值之间的差异，是影响预测可靠性的最主要因素。本研究旨在揭示全球变暖后，凉夏年和热夏年在（1）区域尺度气候变化和（2）对水稻生产的影响方面的差异。区域气候模式（RCM）根据GCM产品在排放情景特别报告-A2情景下缩小了日本气候变化的尺度。模拟的日最高/最低温度、日总太阳辐射和月总降水量的变化因目标月份和地区而异。作物模型模拟表明，气候变化减少了整个日本凉爽夏季造成的损害。另一方面，气候变化增强了日本中部至西南部的热胁迫造成的损害，但即使在炎热的夏季，也没有发现日本北方的损害。由于全球变暖，凉爽的夏季对产量的损害减轻;然而，在后全球变暖的气候中，热胁迫的损害扩大。
A cool summer seriously damages rice production in Japan under the present climate. On the other hand, an extremely hot summer may reduce production because of heat stress during the flowering period in a post-global warming climate. Reliable impact projections are required to grasp the hazards of production variability. However, accuracy limitations of the General Circulation Model (GCM) products obstruct impact projections in a particularly extreme year. A new dynamic downscaling method is suggested by the current study, which contributes to estimating a higher-resolution climate from GCM products while reducing the GCM bias. The bias means the difference between the simulated value and observations, and is the most serious factor in decreasing the reliability of impact projections. This study aims to show the difference in (1) the region-scale climate change and (2) the influence on rice production between a cool summer year and a hot summer year after global warming. A Regional Climate Model (RCM) downscales the change in climate over Japan based on GCM products under the Special Report for Emission Scenario-A2 scenario. Simulated changes in daily maximum/minimum temperatures, daily total solar radiation and monthly total precipitation vary depending on the target month and the area. Crop model simulations show that climate changes reduce the damage caused by a cool summer throughout Japan. On the other hand, climate changes enhance the damage caused by heat stress in central to southwestern Japan, but the damage is not found in northern Japan even in a hot summer year. As the result of global warming, the damage to yield from a cool summer is mitigated; however, damage from heat stress is enlarged in a post-global warming climate.