Study on the uncertainties of methods and precision of net radiation flux measurement

More and more scientists are conscious of the uncertainties of net radiation flux measurements.It has relation not only to the measuring method,but also to the calibrating and maintaining methods of radiometers,especially long-wave radiometer.In this paper,two common measuring methods,which are net pyrradiometer measurement (NPM) and 4-way component system measurement (4CSM) were used to contrast in the fields.The results show that there are uncertainties in error between two measurements,and its precision changes with time and weather condition.Temperature change and unconsistency of windshield penetrant light spectrum of pyrradiometer are reasons on uncertainty of pyrradiometer.