青海省东部干旱风险及对春小麦种植的影响

发布时间：2018-09-01 09:42

【摘要】：青海省东部农业区气候属大陆性高原气候,降水稀少,干旱频发,加上海拔高,气温低,使得当地农业发展极受自然条件限制。农业气象干旱为制约青海农业发展的首要气象灾害,研究其时空变化特征,进行干旱风险性评估非常重要。本文以青海省东部农业区为研究区,根据研究区12个气象站长期的气象资料与生物气象资料,运用最大熵模型及ArcGIS对研究区降水量、干燥度、综合气象干旱指数等气象变量进行了分析,对研究区农业气象干旱进行了风险性评估,得到了青海东部春小麦种植的脆弱性分布。主要研究结果如下:(1)研究区降水量呈现出向东南和西北方向变异发展的趋势,整体降水量由西北向东南逐渐减少。在研究时段内,各年降水量变化范围在295-570mm之间,呈现出随时间增加不断减少的发展趋势。而降水量年内分布极不均匀,降水主要集中在7月份和8月份,11月份到3月份的降水量较少。(2)研究区东南和西北位置的干燥度呈现出先增加后减小的趋势,各年干燥度变化较大,数值变化范围在1.5-3. 1之间,呈现出随时间增加不断增加的发展趋势。从干燥度逐月变化情况来看,研究区在7月份-9月份三个月内的干燥度相对较小,在11月份-3月份之间干燥度较大。而研究区中部的干旱强度要比其它地区高,南部地区发生干旱的持续时间则较长,特旱为研究区历年日干旱能够达到的最高程度。(3)研究区春季干旱有较大强度,随着季节的推移出现了强度和持续时间逐渐增加的趋势,研究区中部地区更易发生春季干旱事件。夏季研究区的干旱强度相对较小,在连续年份会出现大强度干旱事件,研究区南部更容易发生夏季干旱事件。秋季研究区的干旱强度呈现出逐年增加趋势,干旱发生频率较高,研究区南部更容易发生秋季干旱事件,并且干旱持续时间较长。冬季研究区的干旱强度较小,呈现出大强度干旱事件发生可能性逐年增加的趋势,研究区中部更易发生冬季干旱,并且中部和南部发生干旱的持续时间较长。(4)青海省东部农业干旱风险性南北差异显著,中部地区最高。其中泽库人均收入较低,有效灌溉面积少,加之年降水量少,干旱发生频率高,使得当地干旱风险性高;同德中度干旱发生频率较高,且集中在农作物生育期,而且当地对农业依赖性较高,所以同德农业干旱风险性也很高;河南蒙古族自治县的农业干旱脆弱性较低,且降水较少,干旱发生频率高,所以风险性较高;贵南的耕地所占比重较大,但是农业发展水平较高,水浇地比较多,农业干旱风险性相对较低;兴海的农业干旱脆弱性较高,但是其极度和重度干旱发生频率都比较低,使得总体的风险性小一些;共和农业干旱脆弱性和危害性都很低,风险性自然较低。(5)青海东部农业区春小麦的气候脆弱性很大程度受当地的降水条件影响。分析认为民和、贵德和共和地区春小麦气候脆弱性较高,应对气候变化的能力较差,发生农业气象灾害的风险增加。在春小麦的种植方面应着重考虑春季干旱带来的不利影响,创新农业灌溉措施,提高农业灌溉水平。
[Abstract]:The climate of the eastern agricultural region of Qinghai Province belongs to the continental plateau climate with few precipitation, frequent drought, high altitude and low temperature, which makes the development of local agriculture extremely limited by natural conditions. Based on the long-term meteorological and biometeorological data of 12 meteorological stations in the eastern part of Qinghai Province, the meteorological variables such as precipitation, dryness and comprehensive meteorological drought index were analyzed by using maximum entropy model and ArcGIS. The agricultural meteorological drought risk in the study area was evaluated and Qinghai was obtained. The main results are as follows: (1) The precipitation varies from southeast to northwest, and the precipitation decreases gradually from northwest to southeast. During the study period, the annual precipitation varies from 295 mm to 570 mm, showing a decreasing trend with the increase of time. The annual distribution of precipitation is very uneven, mainly in July and August, and less in November and March. (2) The dryness in the southeast and northwest of the study area shows a trend of increasing first and then decreasing, and the annual dryness changes greatly, the numerical range is between 1.5 and 3.1, showing a continuous increase with time. From the perspective of monthly variation of dryness, the dryness of the study area is relatively small in July-September, and relatively large in November-March. The intensity of drought in the middle of the study area is higher than that in other areas, while the duration of drought in the south is longer. The special drought is the calendar year drought in the study area. (3) Spring drought in the study area has a relatively strong intensity, with the gradual increase in intensity and duration of the season, the central region of the study area is more prone to spring drought events. The drought intensity in autumn is increasing year by year, the frequency of drought is higher, the southern part of the study area is more likely to occur in autumn, and the duration of drought is longer. (4) The agricultural drought risk in the eastern part of Qinghai Province is significantly different from that in the north and south, and the highest in the central part of Qinghai Province. The agricultural drought risk in Tongde is very high because of the high frequency of moderate drought in Tongde and the high dependence on agriculture. The agricultural drought vulnerability in Henan Mongolian Autonomous County is low, and the precipitation is low, and the frequency of drought is high, so the risk is high. The agricultural drought vulnerability in Xinghai is relatively high, but the frequency of extreme and severe drought is relatively low, which makes the overall risk smaller. The vulnerability and harmfulness of agricultural drought in Republican China are very low, and the risk is naturally low. The climate vulnerability of spring wheat in the eastern agricultural region is greatly affected by the local precipitation conditions. The analysis shows that the climate vulnerability of spring wheat in Minhe, Guide and Gonghe regions is relatively high, the ability to cope with climate change is poor, and the risk of agrometeorological disasters increases. Influence, innovate agricultural irrigation measures and raise the level of agricultural irrigation.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S423;S512.12

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