hurricanes

Focused Study of Interweaving Hazards Across the Caribbean

Braun J.J, Mattioli G.S., Calais E. Focused Study of Interweaving Hazards Across the Caribbean. EOS Vol. 93, No 9, 28 Feb 2012.

Abstract: 
The Caribbean is a region of lush vegetation, beaches, active volcanoes, and significant mountain ranges, all of which create a natural aesthetic that is recognized globally. Yet these very same features, molded through geological, oceanic, and atmospheric processes, also pose natural hazards for the developing countries in the Caribbean. The rise in population density, migration to coastal areas, and substandard building practices, combined with the threat of natural hazards, put the region’s human population at risk for particularly devastating disasters. These demographic and social characteristics exist against a backdrop of the threat of an evolving climate, which produces a more vigorous hurricane environment and a rising average sea level. The 12 January 2010 earthquake in Haiti and Hurricane Ike (2008) both caused widespread destruction and loss of life, illustrating the need for a scientific focus on the underlying natural hazards of the Caribbean. Prompted by these and other events, a new National Science Foundation (NSF)– funded initiative known as the Continuously Operating Caribbean Observation Network (COCONet), which commits roughly $7 million over 5 years to a collaborative natural hazard research team, was formed in 2010. This team includes researchers from UNAVCO, Purdue University, University of Puerto Rico at Mayagüez, and the University Corporation for Atmospheric Research (UCAR)

Stable isotope ratios of rain and vapor in 1995 hurricanes

Lawrence, JR, SD Gedzelman, XP Zhang, and R. Arnold. 1998. Stable isotope ratios of rain and vapor in 1995 hurricanes. Journal of Geophysical Research-Atmospheres 103 (D10) (MAY 27): 11381-400.

Testing coral-based tropical cyclone reconstructions: An example from puerto rico

Kilbourne, K. Halimeda, Ryan P. Moyer, Terrence M. Quinn, and Andrea G. Grottoli. 2011. Testing coral-based tropical cyclone reconstructions: An example from puerto rico. Palaeogeography Palaeoclimatology Palaeoecology 307 (1-4) (JUL 1): 90-7.

Abstract: 
Complimenting modern records of tropical cyclone activity with longer historical and paleoclimatological records would increase our understanding of natural tropical cyclone variability on decadal to centennial time scales. Tropical cyclones produce large amounts of precipitation with significantly lower δ18O values than normal precipitation, and hence may be geochemically identifiable as negative δ18O anomalies in marine carbonate δ18O records. This study investigates the usefulness of coral skeletal δ18O as a means of reconstructing past tropical cyclone events. Isotopic modeling of rainfall mixing with seawater shows that detecting an isotopic signal from a tropical cyclone in a coral requires a salinity of ~33 psu at the time of coral growth, but this threshold is dependent on the isotopic composition of both fresh and saline end-members. A comparison between coral δ18O and historical records of tropical cyclone activity, river discharge, and precipitation from multiple sites in Puerto Rico shows that tropical cyclones are not distinguishable in the coral record from normal rainfall using this approach at these sites.

Tropical cyclones and the flood hydrology of Puerto Rico

Smith, J. A., P. Sturdevant-Rees, M. L. Baeck, and M. C. Larsen (2005), Tropical cyclones and the flood hydrology of
Puerto Rico, Water Resour. Res., 41, W06020, doi:10.1029/2004WR003530.

Abstract: 
Some of the largest unit discharge flood peaks in the stream gaging records of the U.S. Geological Survey (USGS) have occurred in Puerto Rico. Many of these flood peaks are associated with tropical cyclones. Hurricane Georges, which passed directly over the island on 21–22 September 1998, produced record flood peaks at numerous USGS stations in Puerto Rico. The hydrology and hydrometeorology of extreme flood response in Puerto Rico are examined through analyses of rainfall, based on Weather Surveillance Radar–1988 Doppler (WSR-88D) radar reflectivity observations and USGS rain gage observations and discharge from USGS stream gaging stations. Peak rainfall accumulations of more than 700 mm occurred in the central mountain region of the island. The largest unit discharge flood peaks, however, were located in the eastern portion of the island in areas with smaller storm total rainfall accumulations but markedly larger rainfall rates at 5–60 min timescale. Orographic precipitation mechanisms played an important role in rainfall distribution over the island of Puerto Rico. Amplification of rainfall accumulations was associated with areas of upslope motion. Elevated low-level cloud water content in regions of upslope motion played an important role in the maximum rainfall accumulations in the central mountain region of Puerto Rico. The largest unit discharge flood peaks, however, were produced by a decaying eye wall mesovortex, which resulted in a 30–45 min period of extreme rainfall rates over the eastern portion of the island. This storm element was responsible for the record flood peak of the Rı´o Grande de Lo´iza. The role of terrain in development and evolution of the eye wall mesovortex is unclear but is of fundamental importance for assessing extreme flood response from the storm. Hydrologic response is examined through analyses of rainfall and discharge from five pairs of drainage basins, extending from east to west over the island. These analyses point to the importance of short-term rainfall rates for extreme flood response. The hydrologic response of Puerto Rico is compared with two other extreme flood environments, the central Appalachians and Edwards Plateau of Texas. These analyses suggest that the high rainfall environment of Puerto Rico is linked to the development of a hydraulically efficient drainage system.

Natural disturbance and human land use as determinants of tropical forest dynamics: results from a forest simulator

Uriarte, M., C. D. Canham, J. Thompson, J. K. Zimmerman,
L. Murphy, A. M. Sabat, N. Fetcher, and B. L.
Haines. 2009. Natural disturbance and human land
use as determinants of tropical forest dynamics:
results from a forest simulator. Ecological Monographs
79:423–443.

Abstract: 
Forests are often subject to multiple, compounded disturbances, representing both natural and human-induced processes. Predicting forest dynamics requires that we consider how these disturbances interact to affect species demography. Here we present results of an individual-based, spatially explicit forest simulator that we developed to analyze the compounded effects of hurricane disturbance and land use legacies on the dynamics of a subtropical forest. We used data from the 16-ha Luquillo Forest Dynamics Plot in Puerto Rico, together with a reconstruction of historical wind damage, to parameterize the simulator. We used the model to ask two questions. (1) What are the implications of variation in hurricane frequency and severity for the long-term dynamics of forest composition, diversity, and structure? Both storm severity and frequency had striking effects on forest dynamics, composition, and structure. The periodicity of disturbance also played an important role, with periods of high hurricane activity fostering the establishment of species that may become rare in the absence of severe storms and quiescent periods allowing these species to reach reproductive size. Species responses to hurricane disturbance could not be predicted from their life history attributes. However, species perceived to be primary forest species exhibited low temporal variation in abundance through the simulations. (2) How do hurricanes and legacies from human land use interact to determine community structure and composition? Our results suggest that, over time, regardless of the storm regime, land use legacies will become less apparent but will lead to a forest community that contains a mixture of secondary and primary forest species formerly dominant in areas of different land use. In the long term, hurricane disturbance generated two communities with slightly greater similarity than those not subject to storms. Thus, the inclusion of hurricane disturbance does not alter the prediction that land use legacies in this tropical forest will diminish over time. Our simulations also highlight the contingent effects of human legacies on subsequent community dynamics, including the response to hurricane disturbance, therefore supporting the notion that compounded disturbances can interact in ways that cannot be predicted by the study of single disturbances. The widespread importance of land use as a large-scale disturbance makes it imperative that it be addressed as a fundamental ecological process.

LANDSCAPE AND REGIONAL IMPACTS OF HURRICANES IN PUERTO RICO

Boose, E.R., Serrano, M.I. & Foster, D.R. (2004) Landscape
and regional impacts of hurricanes in Puerto Rico. Ecological
Monographs, 74, 335–352.

Abstract: 
Puerto Rico is subject to frequent and severe impacts from hurricanes, whose long-term ecological role must be assessed on a scale of centuries. In this study we applied a method for reconstructing hurricane disturbance regimes developed in an earlier study of hurricanes in New England. Patterns of actual wind damage from historical records were analyzed for 85 hurricanes since European settlement in 1508. A simple meteorological model (HURRECON) was used to reconstruct the impacts of 43 hurricanes since 1851. Long-term effects of topography on a landscape scale in the Luquillo Experimental Forest (LEF) were simulated with a simple topographic exposure model (EXPOS). Average return intervals across Puerto Rico for F0 damage (loss of leaves and branches) and F1 damage (scattered blowdowns, small gaps) on the Fujita scale were 4 and 6 years, respectively. At higher damage levels, a gradient was created by the direction of the storm tracks and the weakening of hurricanes over the interior mountains. Average return intervals for F2 damage (extensive blowdowns) and F3 damage (forests leveled) ranged from 15 to 33 years and 50 to 150 years, respectively, from east to west. In the LEF, the combination of steep topography and constrained peak wind directions created a complex mosaic of topographic exposure and protection, with average return intervals for F3 damage ranging from 50 years to .150 years. Actual forest damage was strongly dependent on land-use history and the effects of recent hurricanes. Annual and decadal timing of hurricanes varied widely. There was no clear centennial-scale trend in the number of major hurricanes over the historical period.

Hurricane Effects on Soil Organic Matter Dynamics and Forest Production in the Luquillo Experimental Forest, Puerto Rico: Results of Simulation Modeling

Hurricane Effects on Soil Organic Matter Dynamics and Forest Production in the Luquillo Experimental Forest, Puerto Rico: Results of Simulation Modeling
Robert L. Sanford, Jr., William J. Parton, Dennis S. Ojima and D. Jean Lodge
Biotropica
Vol. 23, No. 4, Part A. Special Issue: Ecosystem, Plant, and Animal Responses to Hurricanes in the Caribbean (Dec., 1991), pp. 364-372

Abstract: 
The forests and soils at Luquillo Experimental Forest (LEF), Puerto Rico, are frequently disturbed by hurricanes occurring at various frequencies and intensities. We have derived a forest version of the Century soil organic matter model to examine the impact of hurricanes on soil nutrient availability and pool sizes, and forest productivity in the tabonuco forest at Luquillo. The model adequately predicted aboveground plant production, soil carbon, and soil nitrogen levels for forest conditions existing before Hurricane Hugo. Simulations of Hurricane Hugo and of an historical sequence of hurricanes indicated a complex pattern of recovery, especially for the first 10 yr after the hurricanes. After repeated hurricanes, forest biomass was reduced, while forest productivity was enhanced. Soil organic matter, and phosphorus and nitrogen mineralization stabilized at higher levels for the LEF than for hurricane-free tabonuco forest, and organic soil phosphorus was substantially increased by hurricanes. Results from these simulations should be regarded as hypotheses. At present there is insufficient data to validate the results of hurricane model simulations.

Forecasting hurricane-related disasters

Abstract: 
The punch from hurricane-strength winds is quick. In the Caribbean, the storms whip across the islands tearing out trees and shattering buildings. Monitoring hurricanes is a centuries-long tradition. But with all hurricanes, and even with less formidable rain storms, comes the threat of landslides and flooding to the hills and valleys on the islands' mountainous terrain. To help emergency personnel evacuate regions at high risk to these secondary rain-induced hazards, a consolidation of technology is needed, says Randall Updike of the U.S. Geological Survey in Denver. He is working with colleagues at the USGS, along with scientists from the National Oceanic and Atmospheric Association (NOAA) and NASA, to establish a united front on forecasting landfall disasters from hurricanes in the Caribbean. UNESCO (United Nations Educational, Scientific and Cultural Organization) and The World Meteorological Organization also support the proposed idea, Updike added. Currently these organizations operate independently of each other. Updike presented his proposal of bringing the groups together at the annual meeting of the American Association for the Advancement of Science in Denver on Feb. 15.

CONTROLS OF PRIMARY PRODUCTIVITY: LESSONS FROM THE LUQUILLO MOUNTAINS IN PUERTO RICO

Controls of Primary Productivity: Lessons from the Luquillo Mountains in Puerto Rico
Robert B. Waide, Jess K. Zimmerman and F. N. Scatena
Ecology
Vol. 79, No. 1 (Jan., 1998), pp. 31-37

Abstract: 
The Luquillo Mountains of eastern Puerto Rico are used as a case study to evaluate possible single- or multiple-factor controls of productivity in montane forests. A review of published studies from the Luquillo Mountains revealed that canopy height, productivity, and species richness decline while stem density increases with elevation, as is typical of other montane forests. A mid-elevation floodplain palm stand with high levels of productivity provides a notable exception to this pattern. Previous basic and applied studies of productivity in the Luquillo Mountains have consistently considered the overall gradient in productivity to be important in understanding forest structure and function. Recent observational and experimental studies have determined that disturbance of all types is an important factor mediating productivity in both low- and high-elevation (cloud) forests. For example, low-elevation forest recovers more quickly from hurricane disturbance and is more responsive to nutrient additions than is cloud forest. All of the factors proposed for limiting productivity are supported in one way or another by research in the Luquillo Mountains. What is critically lacking is both an appreciation for the way that these factors interact and experiments appropriate to evaluate multiple controls acting simultaneously.

HURRICANE-INDUCED CHANGES IN VEGETATION STRUCTURE, COMPOSITION AND STOICHIOMETRY IN A SUBTROPICAL WET FOREST

Abstract: 
This paper compares aboveground forest structure and macronutrient stoichiometry over 5 15 years of hurricane induced secondary succession by species, life history groups, community 6 species composition, and geomorphic setting. Stem density continually increased after the 7 impact of the Category 4 hurricane Hugo and 15 years later, it was greater than pre-hurricane. 8 There were significant spatial and temporal differences in the number of species, the diversity 9 index per plot, forest structure, and biomass. The greatest compositional differences occurred 10 between the post-Hugo and the 15-year census. Prior to hurricane Hugo most plots had very 11 similar species composition and abundances, and thus occupied a small area in non-metric 12 multidimensional species space. Following the hurricane new species combinations occurred 13 and the location of plots was spread in multidimensional space. Diversity indices were 14 significantly different among geomorphic settings before and immediately after hurricane Hugo. 15 However, these differences were not observed again until the 15-year census where they returned 16 to pre-hurricane levels. Plant associations based on abundance, life history traits, and landscape 17 position had measurable differences in their structure, composition, aboveground nutrient 18 storage, and stoichiometry. However, these differences were reflected in a variety of ways at 19 different spatial scales. At the species level differences in macronutrient tissue concentrations 20 were apparent when comparing co-existing primary forests dominants, early successional 21 dominants, high-light and low-light species, and species whose stem densities are negatively 22 correlated. Community level differences were greater for forest structure and total nutrient 23 storage compared to the mass weighted concentrations of macronutrients. The largest differences observed were in Mg and can be attributed to the succession of pioneer species 2 following the hurricane. Over the entire 15-year period, the watershed average aboveground 3 stoichiometry was relatively consistent and this is linked to the biomass dominance of a few 4 species. The successional history recorded here also suggests that community level differences 5 in species composition, structure, and stoichiometry were well established after 10 to 15 years of 6 secondary succession.
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