Evaluation of the J-OFURO3 Sea Surface Net Radiation and Inconsistency Correction

Abstract

A new satellite-based product containing daily sea surface net radiation () values at a spatial resolution of 0.25° from 1988 to 2013, named the Japanese Ocean Flux Data Sets with Use of Remote Sensing Observations, version 3 (J-OFURO3), was recently generated and released. In this letter, the performance of the J-OFURO3 sea-surface product was fully evaluated by using observations from 55 global moored buoy sites. The overall accuracy was satisfactory, with root-mean-square difference (RMSD) of 24.05 and 10.76 Wm−2 at daily and monthly scales, respectively. However, an inconsistency issue was found in the long-term variations in the J-OFURO3 sea-surface values in approximately 2000; this inconsistency may be due to the replacement of the input dataset. To address this issue, a simple but effective inconsistency correction method was developed and conducted in this study. The analysis results demonstrated that the variations in the corrected J-OFURO3 sea-surface data were more reasonable and that its daily validation accuracy was significantly improved by decreasing the bias from 4.67 to 0.27 Wm−2 before the year 2000. Thereby, it is suggested that the inconsistency correction method should be applied before using the J-OFURO3 sea-surface data. However, the data users still should be cautious about another discontinuity issues caused by the quality of the input dataset itself.

A global long-term ocean surface daily/0.05° net radiation product from 1983–2020

“…It indicates that most oceans underwent a significant change during 1983–2020 with mostly increasing at mid-high latitudes (red color) and only several increasing (e.g., the Indian Ocean and Tropical Center Pacific) and decreasing hot spots (e.g. the seas to northern Australia, western Africa and South America) over tropical seas, which were coincident with the results of previous studies 13 , 68 – 70 . The remarkable increased ocean surface R n over most oceans at high latitudes where the rate was even as large as 2 Wm −2 per year was speculated caused by the increased absorbed solar radiation because of the reduced ocean surface albedo due to the sea ice or glacier melting caused by global warming 71 , but the case was unexpected over the Norway sea (68°N – 80°N, 10°W – 45°E) where the ocean surface R n overly decreased at a rate of ~0.5 Wm −2 per year.…”

“…Specifically, six products covering 1988–2016 were used for fusion including two remotely sensed products (CERES4 and ISCCP-FH) and four reanalysis products (JRA-55, MERRA2, NCEP R2, and ERA5), and five products were used for comparison including one remotely sensed product (GEWEX-SRB), three reconstructed products (TropFlux, OAFlux, and J-OFURO3), and one ship-based product (NOCS V2.0). Note that J-OFURO3 which was thought to be one of the best products in ocean surface R n 13 was mainly considered as a reference. Table 2 lists the characteristics of the 11 used ocean surface R n products.…”

“…Moreover, some products cover only the ice-free oceans (e.g., the Japanese Ocean Flux Data Sets with Use of Remote Sensing Observations, version3 <J-OFURO3> 2 , the Objectively Analyzed Air-Sea Flux <OAFlux> 9 , 10 , and TropFlux 11 ), and the uncertainty in the R n over the coastal seas is large for most products owing to their coarse spatial resolutions 12 . Furthermore, other problems in these products, such as the discrepancy in accuracy, inconsistency 13 , and short duration, also limit the wide use of the ocean surface R n from them. Therefore, a reliable, long-term time series of the ocean surface R n dataset with a high accuracy and high spatio-temporal resolution is needed.…”

“…According to Chen et al . 13 , it is worth considering inconsistencies in the daily ocean surface R n from J-OFURO3 around 2000, which was primarily caused by the change in input datasets from ISCCP-FD to CERES3. We compared GHOSE and J-OFURO3 in terms of the ocean surface R n for 1988–1999 and 2000–2013 based on the independent evaluation samples.…”

Advances in Land–Ocean Heat Fluxes Using Remote Sensing

“…Fourth, Chen et al [36] evaluated the performance of the J-OFURO3 (the Japanese Ocean Flux Data Sets with Use of Remote Sensing Observations, version3) sea-surface net-radiation data set using buoy observations from 55 sites. The validation results showed that the overall accuracy of J-OFURO3 sea-surface net radiation was satisfactory, but an inconsistency issue occurred in long-term sea-surface net radiation variations.…”