近30年中国主要农业气象灾害典型场时空格局分异特征

在全球气候变暖,气象灾害频发重发的背景下,农业生产受到日益严重的气象灾害影响。研究中国农业气象灾害的时空格局对于降低灾害风险、减轻灾害损失十分重要。本文利用1978—2013年主要省、直辖市及自治区的农业灾害受灾、成灾面积和播种面积资料,以受灾率和成灾率作为指标,利用经验正交函数(Empirical Orthogonal Function,EOF)等统计分析,对影响我国农业生产的主要农业气象灾害(干旱灾害、洪涝灾害、低温冻害和风雹灾害)的时空变化进行分析并得到典型场。结果表明,近几年除洪涝灾害没有明显的升降趋势以外,干旱、风雹和低温冻害受灾率成灾率均呈下降趋势。干旱受灾率和成灾率典型场较为相似,北方因灾损失情况明显重于南方;全国大部分地区均有轻微的因风雹灾害造成损失的情况,西部和西北部容易受到风雹灾害的影响;洪涝灾害受灾率和成灾率典型场存在差异,全国普遍受到洪涝灾害轻微影响,但长江流域和东北三省情况较重。低温冻害受灾、成灾率的典型场不明显,北方因灾损失程度重于南方。另外,干旱和洪涝灾害不会持续影响东北地区;风雹灾害在我国西北部容易造成持续且严重的影响。总之,各灾害的受灾、成灾率时间变化也不是完全同步的,空间分布也不相同,二者并不是完全匹配的。

Spatio-temporal patterns of typical agro-meteorological disasters in China in the past 30 years

Even though China, like any other country, is vulnerable to the adverse effects of climate change, agriculture is a vital industry in the country. In the context of global warming and frequent extreme weather and climate events, agricultural production in China has been affected by the increasingly severe meteorological disasters. It is very important to study the spatio-temporal patterns of agro-meteorological disasters in China in order to mitigate disaster risks and reduce disaster losses. In this paper, the spatial and temporal changes and the typical patterns of main meteorological disasters (i.e., drought, flood, low-temperature and hailstorm disasters) affecting agriculture in China from 1978 to 2013 were analyzed using Empirical Orthogonal Function (EOF) method. The results showed that drought (starting in 2000), hailstorm (beginning in 2001) and low temperature (starting in 2008) all decreased in trend. However, there was no obvious trend in flooding. The EOFs of drought that caused 10% and 30% yield losses were similar, and the losses in the North were obviously higher than those in the South. The EOFs of flood that caused 10% and 30% yield loss were quite different. Flood area with 30% yield loss was mainly distributed in the Yangtze River Basin and the Northeast. However, flood area with 10% yield loss was widely distributed throughout the country. The low temperature disaster in the northern area was more severe than in the southern area. Hailstorm in the western area and the northern area was much serious. Droughts and floods did not affect the northeastern plain throughout the year, but caused serious yield losses. Low temperature disaster persistently affected most areas of China, but with little serious losses. Hailstorm caused persistent and serious losses. Combined with statistical and EOFs analyses, we found that the spatial and temporal patterns and the dynamics of the four disasters with 10% and 30% yield loss were not consistent in disaster degree, affected areas and disaster duration.