Solar irradiance observations with PREMOS filter radiometers on the PICARD mission: In-flight performance and data release

Abstract

Context. The PREcision Monitoring Sensor (PREMOS) is a solar radiometer on board the French PICARD mission that was launched in June 2010 and decommissioned in April 2014. Aims. The PREMOS radiometer obtains solar irradiance measurements in specific spectral windows in the UV, visible, and nearinfrared. In this paper, the PREMOS data and calibration methods are presented. Methods. Using back-up channels, the degradation can theoretically be assessed to correct operational channels. However, a strong degradation within all PREMOS channels requires the application of additional methods, namely using back-up channels and assessing the degradation via a proxy-based model. Results. The corrected Level 3 PREMOS data are then used in different contexts in order to be validated. First, the signature of the p-mode are retrieved from the PREMOS data. The Venus transit allows us to empirically determine the intrinsic noise level within the PREMOS high cadence data for the visible and near-infrared channels. We then compare the PREMOS data directly to other data sets, namely from the SOLar-STellar Irradiance Comparison Experiment (SOLSTICE) and the Solar Irradiance Monitor (SIM) instruments on board the SOlar Radiation and Climate Experiment (SORCE) spacecraft. Regarding the UV channels, we found an excellent correlation over the lifetime of the PREMOS mission. The ratio between SORCE and PREMOS observations is always less than 1%. Regarding the SSI measurements in the visible and near-infrared, a comparison of short-term variations (i.e. 27-day modulation) shows a rather good correlation by taking into consideration the intrinsic noise within both SIM and PREMOS observations.

A new observational solar irradiance composite

“…Some deviation after, however, can be seen in the 210 nm channel after May 2012 and in the 215 nm channel from early 2013 onward. At 210 nm Cessateur et al [2016] find a similar deviation when comparing the PREMOS data with SORCE/SOLSTICE (see their Figure 13). We emphasize here that for the comparison shown in Figure 5 both data sets are in absolute values, and both the PREMOS channels and the SOLID composite are not detrended; i.e., they include the long-term trend.…”

“…For that period, the SOLID composite compares well with the observations made by the PREcision Monitoring Sensor [Schmutz et al, 2009] on board the PICARD mission [Thuillier et al, 2006]. Figure 5 shows the SOLID composite convolved with the broadband filters of the PREMOS instrument and the PREMOS observations [Cessateur et al, 2016] centered at 210 nm (left) and 215 nm (right). The agreement between both time series for the two wavelength channels is excellent.…”

Improved Aura/OMI Solar Spectral Irradiances: Comparisons With Independent Data Sets and Model Predictions

“…We already compared the operational SORCE (Béland et al, 2013) data to V2 OMI irradiances, finding a good match between the detrended short-term variability patterns (Marchenko et al, 2016). Finally, we incorporate all the available measurements from the PREcision Monitoring Sensor (PREMOS) on board the PICARD mission (Cessateur et al, 2016). We also use the Global Ozone Monitoring Experiment-2 (GOME-2A: Munro et al, 2016), additionally corrected for the instrument degradation (https://www.eumetsat.int/website/home/TechnicalBulletins/GOME2/DAT_3036881.html).…”

“…The correction proves to be quite adequate on a short-term basis, nevertheless severely limiting use of the GOME-2A data on the solar cycle time frame. Finally, we incorporate all the available measurements from the PREcision Monitoring Sensor (PREMOS) on board the PICARD mission (Cessateur et al, 2016). This particular mission, though relatively short term (June 2010 to April 2014), provides a broad wavelength coverage that is important for our validation effort.…”

Characteristics of solar-irradiance spectra from measurements, modeling, and theoretical approach

“…Up to 250 nm, a clear solar minimum is shown on 10 January 2009 (within a few days). However, in the EUV, the minimum found by SolACES 47 is a few months earlier (August 2008). The early 2009 date of minimum is roughly consistent with the study by 48 that found a date of late 2008 for the minimum in TSI, Mg II, and F10.7.…”