density (calculated at the same height as wind speed), $\rho_{\text{mean}}$ is the mean density over the entire period of record of the reanalysis product, and the exponent $1/3$ is derived from the basic relationship between wind power and wind speed cubed [@manwell2010wind]. To calculate air density at the same height as wind speed, we first extrapolate the reported surface pressure to the wind speed measurement height, assuming hydrostatic equilibrium [@atmosphere1975iso]: $$p = p_{\text{surf}} \: \exp \left[ \frac{g z}{RT_{\text{avg}}} \right]$$ where $p$ is the pressure at the wind speed measurement height, $p_{\text{surf}}$ is the surface pressure, $g$ is the acceleration caused by gravity, $z$ is the wind speed measurement height, $R$ is the gas constant, and $T_{\text{avg}}$ is the average temperature between the reported value at 2 m AGL and at the wind speed measurement height.

![image](f01){width="16cm"}

To lessen the impact of limited and/or poor-quality data on the results of our analysis, we filter for wind plants with a moderate-to-strong correlation with all three reanalysis products ($R^2 >$ 0.6). About 25% of the EIA wind plants are discarded with this filter. We also impose a threshold of eight months of wind plant data availability in order to investigate uncertainty as it 