光热型电测日照计测量仿真研究

日照时数对天气监测、农业生产、能源开发等有重要作用,是地面气象观测的基本内容之一。基于热电偶测温原理,设计了一种光热型电测日照计。利用金属丝的辐射升温和热传导的基本理论,建立热电偶冷热端的温差和直接太阳辐照度的响应关系,并研究了热电偶金属丝粗细、长短比例、比热、导热系数对测量响应的影响,仿真了直接太阳辐照度恒定不变时的响应关系和太阳间断性直射的响应关系,并进行了对比试验。结果显示：金属丝粗细、长短比例、比热、导热系数均是该日照计的关键影响参数；直接太阳辐照度与热电偶冷热端温差呈良好的线性关系；光热型电测日照计的测量响应时间小于15 s,满足WMO要求。

Measurement Simulation of Photo-Thermal Sunshine Recorder

Sunshine duration plays an important role in weather monitoring,agricultural production and energy de-velopment. It’s one of basic items of the surface meteorological observation. A new photo-thermal sunshine recorder is constructed based on thermocouple temperature measuring principle. Starting from the thermal radiation theory and heat conduction theory,a relationship between the temperature difference of thermocouple and the direct solar irradiance is established. This paper also studies the influence of thermocouple wire thickness,ratio,specific heat and thermal conductivity on measurement;the response of constant direct solar irradiance and intermittent solar irra-diance is simulated;at last the filed comparative experiments are conducted. The results show that,wire thickness, ratio,specific heat and thermal conductivity are crucial parameters of the thermocouple;the direct solar irradiance and the temperature difference of thermocouple show good linear correlation,the response time is less than 15 s, which meets the requirements of WMO.