宁夏中部干旱带压砂地与荒漠草原辐射特征研究

Study on Radiation Characteristics of Gravel-Mulched Fields and Desert Grassland in the Central Arid Zone of Ningxia

摘要:

利用2021年压砂地和荒漠草原（简称“草地”）逐小时净辐射通量、土壤热通量资料，基于常规气象统计方法，对比分析不同时间尺度净辐射通量和土壤热通量的变化特征，探讨不同下垫面能量平衡分量的变化规律。结果表明：（1）压砂地、草地净辐射通量在一年内总体上呈现“两头低、中间高”的变化规律，且压砂地的净辐射通量总体上高于草地；两种下垫面土壤热通量变化平缓，春、夏季压砂地土壤热通量低于草地，而秋冬季则正好相反。（2）压砂地、草地净辐射通量月总量在年内呈现先升后降的趋势，最大值均出现在7月，最小值分别出现在12月和1月；土壤热通量变化平缓，最大值均出现在5月，最小值分别出现在11月和12月。（3）不同月份压砂地、草地净辐射通量和土壤热通量月平均日变化均呈单峰型，土壤热通量日峰值较净辐射通量滞后1～2小时；压砂地净辐射通量日峰值高于草地，且不同月份差异很大，而土壤热通量日峰值差异较小。（4）在不同类型天气条件下，压砂地、草地的净辐射通量和土壤热通量具有明显不同的日变化特征，且日变化趋势和幅度有明显的季节差异。此外，两种下垫面的净辐射通量和土壤热通量波动幅度均表现出晴天＞阴天、扬沙/沙尘暴＞雨/雪天。

Abstract:

Using the hourly data of net radiation flux and soil heat flux in gravel-mulched fields and desert grassland in 2021, based on conventional meteorological statistical methods, the change characteristics of net radiation flux and soil heat flux at different time scales were compared and analyzed, and the change rules of energy balance components of different underlying surfaces were discussed. The results indicate that: (1) the net radiation flux of gravel-mulched fields and grassland is lower at two ends and higher in the middle, and the net radiation flux of gravel-mulched fields is higher than that of grassland. The soil heat flux of the two types of underlying surface changes gently, and the soil heat flux of the gravel-mulched fields in spring and summer is lower than that of the grassland, but it is just the opposite in autumn and winter. (2) The monthly total net radiation flux of gravel-mulched fields and grassland shows a trend of first increasing and then decreasing, with the maximum value appearing in July and the minimum value appearing in December and January, respectively. The variation of soil heat flux is gentle, with the maximum value appearing in May and the minimum value appearing in November and December respectively. (3) The monthly average daily changes of net radiation flux and soil heat flux in different months are unimodal, and the daily peak value of soil heat flux lags behind the net radiation flux by 1 ~ 2 hours. The daily peak value of net radiation flux in gravel-mulched fields is higher than that in grassland, and the difference is great in different months, while the daily peak value of soil heat flux is small. (4) Under different weather conditions, the net radiation flux and soil heat flux of gravel-mulched fields and grassland have different diurnal variation characteristics, and the diurnal variation trend and amplitude have obvious seasonal differences. In addition, the fluctuation amplitude of net radiation flux and soil heat flux of the two types of underlying surface is the largest in sunny days, followed by cloudy days, sand blowing/sandstorm, and the smallest in rain/snow days.