绝对辐射计预测辐射电补偿的快速测量方法

Rapid Measurement Method of Absolute Radiometer by Using Forecast Radiation in Electrically Heating Compensation

绝对辐射计测量光辐射需要接收辐射和电定标两个阶段,这两个阶段都要使辐射计的接收腔达到热平衡才能比较它们的腔温响应,电定标其辐射量值。根据绝对辐射计接收腔在光入射(或电加热)时腔温升响应的指数变化规律,研究出在辐射入射腔之初就动态预测其功率,电加热补偿,使腔的温度在接收辐射和电定标阶段维持恒定的状态下,快速达到平衡进行测量的新方法。为世界辐射中心(PMOD/WRC)研制的两台太阳辐照绝对辐射计SIAR2a和SIAR2b采用了这种快速测量的方法。并在世界辐射中心进行一年半10000多次同世界标准(辐射计)组(WSG)一起同时观测太阳辐照度的比对实验,结果表明其绝对辐射精度达到了0.08%,既保持了原有测量方法(慢速热平衡、测量时间长)的精度,又缩短了秒测量时间。

Two phases of radiation reception and electrical calibration are needed for absolute radiometer to measure radiation. Because absolute radiometer is thermoelectricity detector, at the two phase temperature response of the cavity could be compared after the receive cavity of the absolute radiometer reaches balance, and then the radiation value is electrically calibrated. According to the law that the temperature of the reception cavity rises up exponentially when radiated or heated up, dynamic forecast of the temperature is adopted and then it gets compensation by healing up with electricity. A new method of measurement is worked out under the state that the temperature of the cavity maintains invariable both at the phases of observation and calibration. The rapid measurement method was used on two Solar Irradiance Absolute Radiometers (SIARs) named SIAR-2a and SIAR-2b constructed for Physikalisch-Meteorologisches Observatorium Davos/World Radiometric Center (PMOD/WRC). Comparison experiments were carried at WRC for a year and a half. The sun was observed together with the instruments of WSG more than 10000 times at the same time. The data obtained from PMOD/WRC shows that its absolute precision reaches 0.08%. The precision of the new method is same with the old one (the balance is slower and the measurement time is longer) but the measurement cycle is shorter.