arXiv subjects

Kechi Nzerem

Publications and source records attributed to Kechi Nzerem.

6 recordsLinked to original sources

arXiv2025

The spatially variable effects of mangroves on flood depths and losses from storm surges in Florida

Mangroves modify storm surges with impacts on property damages, but these effects vary spatially and by storm intensity. We use high-resolution, kilometer-scale flood and loss models to examine variability in mangrove effects on surge losses to properties, spatially and by storm intensity, in Florida. We estimate that mangroves reduce property surge losses by $67 million annually in Collier County in southwestern Florida. More than 50% of this reduction occurs for storms with return periods under 30 years. Mangroves in Florida reduced storm surge damages by 14% during Hurricane Irma (2017) and 30% during Hurricane Ian (2022). We show that mangrove presence always reduces flood losses for properties landward of mangroves. Inside mangroves, their effect is a net reduction in damages, though in some locations, especially for more seaward properties, mangroves can increase storm damages. These findings underline the importance of mangrove presence in determining property damages during hurricanes.

q-bio.PE↗

arXiv2007

Predicting landfalling hurricane numbers from basin hurricane numbers: statistical analysis and predictions

One possible method for predicting landfalling hurricane numbers is to first predict the number of hurricanes in the basin and then convert that prediction to a prediction of landfalling hurricane numbers using an estimated proportion. Should this work better than just predicting landfalling hurricane numbers directly? We perform a basic statistical analysis of this question in the context of a simple abstract model, and convert some previous predictions of basin numbers into landfalling numbers.

physics.ao-ph↗

arXiv2007

Predicting basin and landfalling hurricane numbers from sea surface temperature

We are building a hurricane number prediction scheme based on first predicting main development region sea surface temperature (SST), then predicting the number of hurricanes in the Atlantic basin given the SST prediction, and finally predicting the number of US landfalling hurricanes based on the prediction of the number of basin hurricanes. We have described a number of SST prediction methods in previous work. We now investigate the empirical relationship between SST and basin hurricane numbers, and put this together with the SST predictions to make predictions of both basin and landfalling hurricane numbers.

physics.ao-ph↗

arXiv2007

Predicting landfalling hurricane numbers from sea surface temperature: theoretical comparisons of direct and indirect approaches

We consider two ways that one might convert a prediction of sea surface temperature (SST) into a prediction of landfalling hurricane numbers. First, one might regress historical numbers of landfalling hurricanes onto historical SSTs, and use the fitted regression relation to predict future landfalling hurricane numbers given predicted SSTs. We call this the direct approach. Second, one might regress \emph{basin} hurricane numbers onto historical SSTs, estimate the proportion of basin hurricanes that make landfall, and use the fitted regression relation and estimated proportion to predict future landfalling hurricane numbers. We call this the \emph{indirect} approach. Which of these two methods is likely to work better? We answer this question for two simple models. The first model is reasonably realistic, but we have to resort to using simulations to answer the question in the context of this model. The second model is less realistic, but allows us to derive a general analytical result.

physics.ao-ph↗

arXiv2007

Correlations between hurricane numbers and sea surface temperature: why does the correlation disappear at landfall?

There is significant correlation between main development region sea surface temperature and the number of hurricanes that form in the Atlantic basin. The correlation between the same sea surface temperatures and the number of \emph{landfalling} hurricanes is much lower, however. Why is this? Do we need to consider complex physical hypotheses, or is there a simple statistical explanation?

physics.ao-ph↗

arXiv2006

Change-point detection in the historical hurricane number time-series: why can't we detect change-points at US landfall?

The time series of the number of hurricanes per year in the Atlantic basin shows a clear change of level between 1994 and 1995. The time series of the number of hurricanes that make landfall in the US, however, does not show the same obvious change of level. Prima-facie this seems rather surprising, given that the landfalling hurricanes are a subset of the basin hurricanes. We investigate whether it really should be considered surprising or whether there is a simple statistical explanation for the disappearance of this change-point at landfall.

physics.ao-ph↗