Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1412.2201

Hurricane Effects on Mangrove Canopies Observed from MODIS and SPOT Imagery

Michael S. Parenti
View original source ↗Read source document ↗Export metadata ↓

Abstract

The effects of two hurricanes (Katrina and Wilma) on protected mangroves in southwest Florida and two hurricanes (Emily and Dean) on protected mangroves in the Yucatan Peninsula were assessed paired sets of 20m multispectral SPOT and 16-day 500m MODIS images. Normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) values were calculated to measure mangrove canopy reflectance using three methods of analysis- 1) mangrove NDVI sample point extraction, 2) qualitative assessment of 500m MODIS NDVI and EVI time series, and 3) transects of NDVI differences before and after storm events. Results show each method effectively captures changes in mangrove canopies consistent with storm effects. However, the extent of damage to mangroves in South Florida and Sian Ka'an was highly variable. Hurricanes Wilma and Katrina produced a large drop in NDVI although NDVI values recovered within a year, suggesting remarkable resilience. Hurricane Emily apparently increased mangrove photosynthetic activity owing to the location of landfall relative to the study area, the size of the wind field and the apparent lack of storm surge. Comparison of SPOT NDVI and MODIS NDVI values revealed that the changes pre- and post-storms were consistent at the different scales of observation.

Explore related subjects

physics.ao-ph

Keep this discovery

BibTeXRIS

Michael S. Parenti. 2014-12-06. Hurricane Effects on Mangrove Canopies Observed from MODIS and SPOT Imagery. https://arxiv.org/abs/1412.2201

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Windowed Envelope Statistics for Time-Domain Significant Wave Height Estimation From HF Radar

Significant wave height (SWH) retrieval from high-frequency (HF) radar typically relies on a weak second-order Doppler continuum that is sensitive to noise, interference, and spectral leakage. This letter presents a Windowed Envelope Statistics Estimator (WESE) that operates directly on beam-formed time-domain voltages. A second-order term obtained from a Neumann expansion of the rough-surface field equation motivates quadratic compensation of localized radar features. WESE extracts the mean, standard deviation, or variance from overlapping windows of the in-phase, quadrature, or envelope-magnitude sequence, followed by quadratic compensation, rank ordering, least-squares regression, and causal smoothing. Evaluation used 335 synchronized hourly observations from a 13.385 MHz, 12-element WERA system at Argentia, Newfoundland and Labrador. The optimal configuration used quadrature variance, a 16-sample window, 896 retained chronological samples, and 30-h smoothing, achieving an RMSE of 0.152 m and a Pearson correlation of 0.978. This represents RMSE reductions of 32.1% and 18.7% relative to previously reported linear and second-order compensated ordered-statistics models, respectively. The results demonstrate robust time-domain SWH estimation without explicit Doppler-spectrum construction.

physics.ao-ph↗
arXiv2026

KiloDA: Reconstructing kilometer-scale near-surface wind states from sparse station observations

Accurate kilometer-scale near-surface winds are important for understanding atmospheric processes over complex terrain, yet remain difficult to reconstruct from sparse and unevenly distributed observations. Here we introduce KiloDA, a diffusion framework for hourly kilometer-scale wind reconstruction from surface stations. KiloDA learns the statistical distribution and spatial structure of wind fields from historical 3-km Weather Research and Forecasting (WRF) model forecasts. At each reconstruction time, no contemporaneous WRF field is used. Instead, station observations provide the only constraints on the current atmospheric state and guide posterior sampling from the learned prior. In idealized WRF experiments, KiloDA recovers localized wind structures when only 0.24% of grid cells are observed and shows an overall advantage over conventional interpolation across terrain conditions and wind speed regimes. This capability largely transfers to real observations. In a fully withheld region, KiloDA reduces the median wind speed root mean square error (RMSE) by 19% relative to ERA5 reanalysis, using only observations outside the region, with the largest improvements over high-elevation and high-relief terrain. A random station holdout further confirms that this advantage extends across different complex-terrain locations and holdout configurations. These results show that historical model archives can provide useful structural knowledge for reconstructing kilometer-scale wind fields from sparse observations without requiring an accurate model estimate of the current atmospheric state.

physics.ao-ph↗