Evaluation of the hourly ERA5 radiation product and its relationship with aerosols over China

Li, Zhigang; Yang, Xin; Tang, Hong

doi:10.1016/j.atmosres.2023.106941

Cited by 5 publications

(2 citation statements)

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“…Similar underestimates of the DHI irradiances and overestimates of the DIRhor irradiances are found for all of the SURFRAD, SOLRAD, and ARM-SGP sites. We note that Wu et al [17], Jiang et al [18], and Li et al [19] also found similar opposing diffuse and direct beam biases in the ERA5 in China, demonstrating the consistency of these errors across diverse geographic regions.…”

Section: Evaluation and Bias Correction Of Era5-derived Solar Capacit...supporting

confidence: 69%

“…Using a network of 17 stations in China, Wu et al [17] found that the ERA5 underestimates the diffuse irradiance, while Jiang et al [18], using an observation network of 39 stations in China, found that the ERA5 underestimates diffuse radiation by 43 Wm −2 , but overestimates the direct radiation by 74 Wm −2 . Using observations from 14 stations, Li et al [19] also found a negative ERA5 bias for diffuse irradiance, and a positive bias for the direct beam, and concluded that, in addition to cloud effects, at least part of these biases can be attributed to aerosols. Finally, Mathews et al [20] demonstrate that, if uncorrected, the solar irradiance errors in reanalysis data sets, including the ERA5, can lead to distortions in the total energy requirement of long-duration energy storage infrastructure in grid planning studies.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation and Bias Correction of the ERA5 Reanalysis over the United States for Wind and Solar Energy Applications

Wilczak,

Akish,

Capotondi

et al. 2024

Energies

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The applicability of the ERA5 reanalysis for estimating wind and solar energy generation over the contiguous United States is evaluated using wind speed and irradiance variables from multiple observational data sets. After converting ERA5 and observed meteorological variables into wind power and solar power, comparisons demonstrate that significant errors in the ERA5 reanalysis exist that limit its direct applicability for a wind and solar energy analysis. Overall, ERA5-derived solar power is biased high, while ERA5-derived wind power is biased low. During winter, the ERA5-derived solar power is biased high by 23% on average, while on an annual basis, the ERA5-derived wind power is biased low by 20%. ERA5-derived solar power errors are found to have consistent characteristics across the contiguous United States. Errors for the shortest duration and most extreme solar negative anomaly events are relatively small in the ERA5 when completely overcast conditions occur in both the ERA5 and observations. However, longer-duration anomaly events on weekly to monthly timescales, which include partially cloudy days or a mix of cloudy and sunny days, have significant ERA5 errors. At 10 days duration, the ERA5-derived average solar power produced during the largest negative anomaly events is 62% greater than observed. The ERA5 wind speed and derived wind power negative biases are largely consistent across the central and northwestern U.S., and offshore, while the northeastern U.S. has an overall small net bias. For the ERA5-derived most extreme negative anomaly wind power events, at some sites at 10 days duration, the ERA5-derived wind power produced can be less than half of that observed. Corrections to ERA5 are derived using a quantile–quantile method for solar power and linear regression of wind speed for wind power. These methods are shown to avoid potential over-inflation of the reanalysis variability resulting from differences between point measurements and the temporally and spatially smoother reanalysis values. The corrections greatly reduce the ERA5 errors, including those for extreme events associated with wind and solar energy droughts, which will be most challenging for electric grid operation.

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Section: Evaluation and Bias Correction Of Era5-derived Solar Capacit...supporting

confidence: 69%