In this paper, we propose a novel forecast method which addresses the difficulty in short-term solar irradiance forecasting that arises due to rapidly evolving environmental factors over short time periods. This involves the forecasting of Global Horizontal Irradiance (GHI) that combines prediction sky images with a Radiative Transfer Model (RTM). The prediction images (up to 10 min ahead) are produced by a non-local optical flow method, which is used to calculate the cloud motion for each pixel, with consecutive sky images at 1 min intervals. The Direct Normal Irradiance (DNI) and the diffuse radiation intensity field under clear sky and overcast conditions obtained from the RTM are then mapped to the sky images. Through combining the cloud locations on the prediction image with the corresponding instance of image-based DNI and diffuse radiation intensity fields, the GHI can be quantitatively forecasted for time horizons of 1–10 min ahead. The solar forecasts are evaluated in terms of root mean square error (RMSE) and mean absolute error (MAE) in relation to in-situ measurements and compared to the performance of the persistence model. The results of our experiment show that GHI forecasts using the proposed method perform better than the persistence model.
In order to real-time online monitoring the reaction substrates for biological processes, we designed an on-line Fourier transform infrared spectrometer measurement system, which has the advantages of low cost, simple and compact structure, good reliability, and strong shock resistance compared with the traditional Fourier transform infrared spectrometer. This system consists of two core components, i.e., a high-performance interferometer and an attenuated total reflectance (ATR) probe. In the interferometer, we 1) combined corner cube mirrors and flat mirrors to avoid tilting of the moving mirror; 2) set 60° incident angle to the ZnSe beam splitter to improve the luminous flux; 3) shared folded optical path with both the infrared light and the reference laser to improve compactness in structure; and 4) drive the moving mirror by a parallelogram swing flexible support module to make it move smoothly. In the ATR probe, we utilized two large diameter and inner coating light pipes to transmit the incident and outgoing light to enhance the luminous flux further. We also simulated the optical system and did some off-line and online measurement experiments. The results show the spectrometer has satisfactory reliability, large luminous flux, and online measurement capability. It can be real-time online monitoring the biological process through measuring the concentration of the related bioreactor reactant. The online analysis has wide application prospects in biological, chemical testing, material analysis, and many other fields.
Aerosols and clouds play important roles in the climate system through their radiative effects and their vital link in the hydrological cycle. Accurate measurements of aerosol and cloud optical and microphysical properties are crucial for the study of climate and climate change. This study develops/improves retrieval algorithms for aerosol single scattering albedo (SSA) and low liquid water path (LWP) cloud optical properties, evaluates a new spectrometer, and applies long-term measurements to establish climatology of aerosol and cloud optical properties. The following results were obtained.