Adjustments for Wind Sampling Errors in an Estimate of the Atmospheric Water Budget of the Mississippi River Basin

Abstract

Abstract The spurious mass divergence found in observed and analyzed atmospheric wind fields causes errors in estimated energy flux divergence. An objective method for correcting these errors in radiosonde-based atmospheric water and energy budgets is developed. The proposed method is compared with other correction methods for estimating the moisture budget over the Mississippi River basin. The proposed method adjusts the spatial weights applied at each radiosonde station in the calculation of divergence. The adjustment is done in a least squares sense to minimize the modification to the weights under the constraint of mass conservation (accounting for surface pressure tendency) by use of Lagrange multipliers. The weight adjustment requires fewer and less arbitrary assumptions than existing methods. The adjustment scheme is particularly useful for diagnosing different components of energy transport (e.g., eddy, mean advection, mean divergence) because the adjustment is applied equally to all terms, unlike...