Rain catch under wind and vegetal cover effects

Wind effects on a rain gauge can cause a significant underestimation of rai nfall depths and contribute to the inconsistency in rainfall data. To recon struct rainfall data requires a consistent method to quantify the undercatc h. Although some empirical adjustment factors have been recommended, they a re not generalized enough to reflect the variations of wind speed with resp ect to height. This paper presents a model by which the undercatch at an el evated rain gauge can be estimated by the logarithmic wind velocity profile and raindrop terminal velocity. Deficiency percentages of rain catch predi cted by this model agree with field observations and recommended adjustment factors. This approach was further expanded to predict rain undercatch per centage due to vegetal coverage or other obstructions.