Transfer radiometer is the critical calibration facility of remote sensing instruments on satellites to achieve spectral radiometric calibration on-orbit. It’s also the core for spectral calibration with high accuracy in the laboratory on earth. This paper compares the similarities and differences between several transfer radiometers developed by various institutes covering 200~700, 700~2 000 nm spectrum bandwidth separately through describing their construction, design and operational principles and the method of transferring radiometric calibration benchmark. It shows the realizable accuracy of every transfer radiometers by introducing their central technology applied in the calibration procedures of different wavelength range. The advantages and shortcomings together with every transfer radiometer determine the application circumstance. According to the Introduction of the process of the calibration traceability based on radiance standard in international institutes of standard technology,it emphasizes the importance of transfer radiometers in the procedure. It demonstrates the significance of transfer radiometer in radiometric calibration of aeronautics and space through its application of monitoring the calibration light source for spectrometers. Finally, it presents the prospect for the development and crucial issues of transfer radiometer’s technology in the future research through describing the new transfer radiometer designed in internal institute. Simultaneously, it predicts and summarizes difficult problems required to be solved in the future as to high-accuracy calibration transferring system on-orbit against SI-traceable primary standard, which consists of cryogenic radiometers and transfer radiometers.
Download full-text PDF |
Source |
---|
Hum Reprod
December 2024
Department of Public Health, University of Copenhagen, Copenhagen, Denmark.
Solar heating of the upper ocean is a primary energy input to the ocean-atmosphere system, and the vertical heating profile is modified by the concentration of phytoplankton in the water, with consequences for sea surface temperature and upper ocean dynamics. Despite the development of increasingly complex modeling approaches for radiative transfer in the atmosphere and upper ocean, the simple parameterizations of radiant heating used in most ocean models can be significantly improved in cases of near-surface stratification. There remains a need for a parameterization that is accurate in the upper meters and contains an explicitly spectral dependence on the concentration of biogenic material, while maintaining the computational simplicity of the parameterizations currently in use.
View Article and Find Full Text PDFRadiative transfer simulations of measurements performed with the Skylight-Blocked Approach (SBA) for water exhibiting diverse optical properties confirmed the non-negligible impact of the depth z of the radiometer shield in the determination of the water-leaving radiance L. In particular, results showed that the shield-shaded water volume lowers the measured L value by a few up to tens of percent as a function of the depth z, water attenuation, and wavelength. The study also confirmed the potential applicability of an analytical correction scheme based on the sole water absorption and backscattering coefficients to support operational SBA measurements, still at the expense of decreased accuracy with increasing depth z and water turbidity.
View Article and Find Full Text PDFSensors (Basel)
October 2024
School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
The TianQin program is an independently proposed space-borne detection initiative from China. The inertial sensor, as a crucial component, is susceptible to disturbances from temperature fluctuations, the impact of which on acceleration measurements remains elusive. Therefore, a comprehensive analysis on the influence of temperature disturbance is necessary to avoid errors in acceleration measurement.
View Article and Find Full Text PDFThe accuracy of the absolute radiometric calibration (RadCal) for remote sensing instruments is essential to their wide range of applications. The uncertainty associated with the traditional source-based RadCal method is assessed at a 2% (=1) or higher level for radiance measurement. To further improve the accuracy to meet the demands of climate studies, a detector-based approach using tunable lasers as a light source has been devised.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!