The JSTIM-DARA product derived from the TSI Observations Recorded by the FY3E/JTSIM/DARA Radiometer

Since the late 1970s, successive satellite missions have been monitoring solar activity and recording Total Solar Irradiance (TSI) data. The Digital Absolute
Radiometer (DARA) on board the Chinese FY3E spacecraft was launched on July 4, 2021, and  has since been recording TSI observations. Here, we analyze these observations and assess the performance of DARA, including sensor degradation of 5 ppm after 2 years in orbit, resulting from exposure to ultraviolet and extreme ultraviolet radiation. Comparing the new dataset’s mean values with observations from active  instruments on other spacecraft (i.e., PMO6 on board the VIRGO/SOHO and the TIM/TSIS), along with the Solar Irradiance Absolute Radiometer (SIAR) also on board  FY3E/JTSIM, we find that DARA observations closely align with TIM/TSIS, with a difference of approximately 0.07 W/m2. Based on these findings, we generate a new TSI dataset (JTSIM-DARA product) at a 6-hour sampling interval. Finally, we have incorporated this new dataset into the TSI composite time series released by the PMOD/WRC. The results indicate that the inclusion of DARA-recorded observations does not alter the consistency, reliability, and stability of the time series.