This paper presents a comprehensive total vertical uncertainty

(TVU) model for topo-bathymetric Light Detection and

Ranging (LIDAR) systems. The TVU model consists of a combination

of analytical uncertainty propagation for the subaerial

(above water) portion and Monte Carlo simulation models

for the subaqueous portion (water surface to seafloor). The

TVU model was tested on a topo-bathymetric LIDAR data set

collected by National Oceanic and Atmospheric Administration’s

National Geodetic Survey (NGS) in Southwest Florida,

U.S., in May 2016 using a Riegl VQ-880-G topo-bathymetric

LIDAR system. The TVU values were compared against the

empirical standard deviation and were found to capture the

variability of uncertainty with depth while providing (slightly)

conservative estimates of uncertainty. The results may be

used to inform data acquisition protocols and data processing

models. The model implementation is now beginning to be

used operationally at NGS for topo-bathymetric LIDAR projects.