气候变化情景下新疆地区作物需水量空间分布规律的研究, 可作为农业用水规划的参考依据。基于新疆维吾尔自治区41个气象站1961-2010年逐日气象数据,分别采用FAO-56 Penman-Monteith公式和单作物系数法计算各站参考作物腾发量和作物系数,由两者的乘积获得棉花和甜菜需水量(crop water requirement,ET_c);运用统计降尺度模型SDSM4.2软件,预测2015-2099年高排放和低排放两种气候情景下各站棉花和甜菜的日ET_c时间序列。结果表明,新疆地区1961-2010年棉花和甜菜在不同生育阶段作物系数变化范围为0.58~1.08,棉花和甜菜生育期多年平均ET_c的空间分布由南部向北部逐渐减小。统计降尺度预测过程中的26个预报因子中,地表平均比湿和地表平均气温与ET_c在多数站点相关性较好。2015-2099年高排放和低排放情景下的ET_c空间分布规律与1961-2010年的类似,但数值小的多。总体上,全疆历史和未来的棉花和甜菜ET_c均以不同程度下降。该研究可为新疆地区灌溉决策及节水规划提供依据。
英文摘要:
Information on the spatial distribution characteristics of crop water requirements in Xinjiang Weiwuer Autonomous Region under the climate change scenarios can be used as references for the agricultural water use planning. Previous research on climate change mainly focuses on the temporal changes analysis of temperature, precipitation, or reference crop evapotranspiration under certain emission scenarios. The effects of climate change on variations of crop water requirements in Xinjiang are limited because the methods are more complex and require participation of multi-disciplinary team. In this study, daily meteorological data from 41 weather stations were collected from 1961 to 2010 in Xinjiang region. There were typical geographical and meteorological differences among the selected 41 sites. Reference crop evapotranspiration and crop coefficients were calculated for each site using the FAO-56 Penman-Monteith equation and the single-crop coefficient method, respectively. Crop water requirement of cotton and sugar beet were obtained through reference crop evapotranspiration multiplied by crop coefficient. The statistical downscaling model (SDSM 4.2 software) was applied to each site of the region to project daily crop water requirement sequence of cotton and sugar beet from year 2015 to 2099 under two emission scenarios of high and low emission. The results showed that crop water requirement for cotton and sugar beet ranged from 0.11 to 1.04 at the initial growth stage, 0.98 to 1.05 at the middle growth stage, and 0.58 and 0.7 at the final growth stage during the period of 1961 to 2010 in Xinjiang. The multi-year average reference crop evapotranspiration over 1961-2010 in Xinjiang area varied from 1.84-2.76 mm/d, and the difference in reference crop evapotranspiration at different geographical locations was obvious. The spatial distributions of multi-year average crop water requirement for cotton and sugar beet during growth stage decreased gradually from the south to the north. crop water requirement of cotton varied from 573.9 to 2 853.2 mm/a and generally decreased from the south to the north of Xinjiang except stations of Yiwu and Wuqia in which there were large values of crop water requirement. Crop water requirement of sugar beet varied from 261.4 to 1 300.8 mm/a and the spatial distributions crop water requirement of sugar beet also decreased from the south to the north gradually. For SDSM projections, among the 26 predictors, the average surface specific humidity and average surface temperature respectively correlated to crop water requirement well (P<0.01) at most of the sites. During 2015-2099 under high and low emission scenarios, multi-year mean crop water requirement values of sugar beet in Xinjiang area were from 93.4 to 576.9 and 87.4 to 574.5 mm/a. The projected multi-year mean crop water requirement values of cotton were from 303.6 to 1 608.0 and 305.0 to 1 640.4 mm/a, which were all smaller than those calculated for the period of 1961-2010. Crop water requirement under both emission scenarios decreased gradually from the south to the north. The spatial distributions of crop water requirement from 2015 to 2099 under high and low emission scenarios were similar to that of crop water requirement over 1961-2010, but were generally smaller in values. Overall, crop water requirement of cotton and sugar beet during the historical and future periods decreased at various extents. This research provides possible changes of crop water requirement in the future in Xinjiang region, which can be useful as a reference for irrigation decision and agricultural water management planning.