黄土高原半干旱区雨养农田地表辐射和能量通量的季节变化

发布时间：2018-03-12 06:32

本文选题：黄土高原　切入点：辐射　出处：《高原气象》2016年02期 　论文类型：期刊论文

【摘要】：黄土高原陇东地区有着特殊的气候背景和下垫面,对这一地区陆气相互作用特征和影响因素的观测分析对改进和发展陆面过程模式以及气候变化研究有重要意义。利用陇东平凉陆面过程与灾害天气观测研究站连续一年的陆面过程观测资料,分析了雨养农田降水量、土壤含水量、辐射、反照率和能量通量的季节变化,以及降水、土壤含水量和农业生产活动对能量分配的影响。结果表明,陇东地区降水量季节分布不均,土壤含水量有明显季节差异,随降水有明显波动;辐射通量的季节变化较为规律,短波辐射的日均值受天气状况影响,波动较大;地表反照率呈明显的季节变化,全年正午反照率最大值为0.83,出现在降雪后,生长季随着作物的生长,反照率下降至0.2以下,农作物收割以后的裸土反照率随降水变化明显,反照率与土壤体积含水量呈明显的线性相关关系;湍流能量通量日循环和季节变化明显,地表能量分配在很大程度上受降水影响,同时农业生产活动也对其有较大影响,主导能量通量有较大的月际波动,潜热通量月平均日变化峰值最大为240.8 W·m~(-2),出现在5月,感热通量为192.5 W·m~(-2),出现在4月;在年尺度上,正午净辐射多被感热通量消耗,感热通量约占35%,潜热通量约占32%,低于灌溉农田;在冬小麦快速生长季(3-5月),潜热通量约占34%,远低于灌溉的冬小麦田,研究站点的蒸散发过程受到水分限制。
[Abstract]:There is a special climatic background and underlying surface in Longdong region of the Loess Plateau. The observation and analysis of the characteristics of land-atmosphere interaction and influencing factors in this area are of great significance for improving and developing the land surface process model and the study of climate change. Using Pingliang Land Surface process and disaster Weather observation Station in Eastern Gansu Province, China is of great significance. The land surface process observation data for the following year, The seasonal variations of precipitation, soil water content, radiation, albedo and energy flux in rain-fed farmland were analyzed, and the effects of precipitation, soil water content and agricultural activities on energy distribution were also analyzed. The seasonal distribution of precipitation is uneven and the soil water content is obviously different with precipitation, the seasonal variation of radiation flux is more regular, and the daily mean value of shortwave radiation is influenced by the weather condition and fluctuates greatly. The surface albedo shows obvious seasonal variation, and the maximum value of noon albedo is 0.83. after snowfall, the albedo decreases to less than 0.2 in the growing season with the growth of crops, and the albedo of bare soil after crop harvest changes obviously with the precipitation. Albedo has obvious linear correlation with soil volumetric water content, the daily cycle and seasonal variation of turbulent energy flux are obvious, the surface energy distribution is affected by precipitation to a great extent, and the agricultural activities also have great influence on it. The dominant energy flux fluctuated greatly, and the maximum diurnal variation of latent heat flux was 240.8 W 路m-1 ~ (-2), which appeared on May, and the sensible heat flux was 192.5 W 路m-1 ~ (-2), which appeared on April. On the annual scale, the noonday net radiation was mostly consumed by sensible heat flux. Sensible heat flux is about 35%, latent heat flux is about 32%, which is lower than irrigated farmland, and in winter wheat growing season 3 ~ 5 months, latent heat flux is about 34%, which is far lower than irrigated winter wheat field. The evapotranspiration process of the research site is limited by water.
【作者单位】：中国科学院寒区旱区环境与工程研究所寒旱区陆面过程与气候变化重点实验室;中国科学院大学;中国科学院平凉陆面过程与灾害天气观测研究站;
【基金】：国家自然科学基金项目(41175009;41375001)
【分类号】：S161

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