Donnelly
Jeffrey P.
Donnelly
Jeffrey P.
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ArticleHow unique was Hurricane Sandy? Sedimentary reconstructions of extreme flooding from New York Harbor(Nature Publishing Group, 2014-12-08) Brandon, Christine M. ; Woodruff, Jonathan D. ; Donnelly, Jeffrey P. ; Sullivan, Richard M.The magnitude of flooding in New York City by Hurricane Sandy is commonly believed to be extremely rare, with estimated return periods near or greater than 1000 years. However, the brevity of tide gauge records result in significant uncertainties when estimating the uniqueness of such an event. Here we compare resultant deposition by Hurricane Sandy to earlier storm-induced flood layers in order to extend records of flooding to the city beyond the instrumental dataset. Inversely modeled storm conditions from grain size trends show that a more compact yet more intense hurricane in 1821 CE probably resulted in a similar storm tide and a significantly larger storm surge. Our results indicate the occurrence of additional flood events like Hurricane Sandy in recent centuries, and highlight the inadequacies of the instrumental record in estimating current flood risk by such extreme events.
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ArticleClimate forcing of unprecedented intense-hurricane activity in the last 2000 years(John Wiley & Sons, 2015-02-23) Donnelly, Jeffrey P. ; Hawkes, Andrea D. ; Lane, D. Philip ; MacDonald, Dana ; Shuman, Bryan N. ; Toomey, Michael R. ; van Hengstum, Peter J. ; Woodruff, Jonathan D.How climate controls hurricane variability has critical implications for society is not well understood. In part, our understanding is hampered by the short and incomplete observational hurricane record. Here we present a synthesis of intense-hurricane activity from the western North Atlantic over the past two millennia, which is supported by a new, exceptionally well-resolved record from Salt Pond, Massachusetts (USA). At Salt Pond, three coarse grained event beds deposited in the historical interval are consistent with severe hurricanes in 1991 (Bob), 1675, and 1635 C.E., and provide modern analogs for 32 other prehistoric event beds. Two intervals of heightened frequency of event bed deposition between 1400 and 1675 C.E. (10 events) and 150 and 1150 C.E. (23 events), represent the local expression of coherent regional patterns in intense-hurricane–induced event beds. Our synthesis indicates that much of the western North Atlantic appears to have been active between 250 and 1150 C.E., with high levels of activity persisting in the Caribbean and Gulf of Mexico until 1400 C.E. This interval was one with relatively warm sea surface temperatures (SSTs) in the main development region (MDR). A shift in activity to the North American east coast occurred ca. 1400 C.E., with more frequent severe hurricane strikes recorded from The Bahamas to New England between 1400 and 1675 C.E. A warm SST anomaly along the western North Atlantic, rather than within the MDR, likely contributed to the later active interval being restricted to the east coast.
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ArticleAssessing sedimentary records of paleohurricane activity using modeled hurricane climatology(American Geophysical Union, 2008-09-18) Woodruff, Jonathan D. ; Donnelly, Jeffrey P. ; Emanuel, Kerry A. ; Lane, D. PhilipPatterns of overwash deposition observed within back-barrier sediment archives can indicate past changes in tropical cyclone activity; however, it is necessary to evaluate the significance of observed trends in the context of the full range of variability under modern climate conditions. Here we present a method for assessing the statistical significance of patterns observed within a sedimentary hurricane-overwash reconstruction. To alleviate restrictions associated with the limited number of historical hurricanes affecting a specific site, we apply a recently published technique for generating a large number of synthetic storms using a coupled ocean-atmosphere hurricane model set to simulate modern climatology. Thousands of overwash records are generated for a site using a random draw of these synthetic hurricanes, a prescribed threshold for overwash, and a specified temporal resolution based on sedimentation rates observed at a particular site. As a test case we apply this Monte Carlo technique to a hurricane-induced overwash reconstruction developed from Laguna Playa Grande (LPG), a coastal lagoon located on the island of Vieques, Puerto Rico in the northeastern Caribbean. Apparent overwash rates in the LPG overwash record are observed to be four times lower between 2500 and 1000 years B.P. when compared to apparent overwash rates during the last 300 years. However, probability distributions based on Monte Carlo simulations indicate that as much as 65% of this drop can be explained by a reduction in the temporal resolution for older sediments due to a decrease in sedimentation rates. Periods of no apparent overwash activity at LPG between 2500 and 3600 years B.P. and 500–1000 years B.P. are exceptionally long and are unlikely to occur (above 99% confidence) under the current climate conditions. In addition, breaks in activity are difficult to produce even when the hurricane model is forced to a constant El Niño state. Results from this study continue to support the interpretation that the western North Atlantic has exhibited significant changes in hurricane climatology over the last 5500 years.
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ArticleGrain-size analysis of hurricane-induced event beds in a New England salt marsh, Massachusetts, USA(Coastal Education and Research Foundation, 2021-03-05) Castagno, Katherine ; Donnelly, Jeffrey P. ; Woodruff, Jonathan D.Tropical cyclones pose a growing threat to coastal infrastructure and livelihood. Because instrumental and historic records are too short to help us understand interactions between tropical cyclones and climate on a longer scale, proxy records are the only means for reconstructing millennia of tropical cyclone impacts. This study determines grain-size trends in storm-induced overwash deposits along a transect of sediment cores from a salt marsh in Mattapoisett, Massachusetts, to characterize sorting trends and compare deposits associated with individual storms. The overwash deposits preserved within the high-marsh peat provide a record spanning the last two millennia. Building on a 2010 study, a different approach was used to accurately determine the grain-size distribution of overwash deposits from cores in a transect running perpendicular to the adjacent sandy/gravely barrier. Although maximum grain-size values are expected to decrease as distance from the barrier increases, not all event deposits that were studied follow this trend within uncertainty. Analysis of the storm event beds reveal a significant difference in settling trends between historic and prehistoric deposits, with historic deposits largely displaying landward-fining trends and prehistoric deposits largely displaying landward-coarsening trends. This suggests changes in the hydrodynamic or that geomorphic regime may have altered the way in which storm beds were deposited at this site. This new in-depth, transect-based approach has utility for improving the accuracy of future storm reconstructions, particularly for events for which no historic record exists.
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PreprintAtlantic hurricanes and climate over the past 1,500 years( 2009-06) Mann, Michael E. ; Woodruff, Jonathan D. ; Donnelly, Jeffrey P. ; Zhang, ZhihuaAtlantic Tropical Cyclone (TC) activity, as measured by annual storm counts, reached anomalous levels over the past decade. The short nature of the historical record and potential issues with its reliability in earlier decades, however, has prompted an ongoing debate regarding the reality and significance of the recent rise. Here, we place recent activity in a longer-term context, by comparing two independent estimates of TC activity over the past 1500 years. The first estimate is based on a composite of regional sedimentary evidence of landfalling hurricanes, while the second estimate employs a previously published statistical model of Atlantic TC activity driven by proxy-reconstructions of past climate changes. Both approaches yield consistent evidence of a peak in Atlantic TC activity during Medieval times (around AD 1000) followed by a subsequent lull in activity. The Medieval peak, which rivals or even exceeds (within uncertainties) recent levels of activity, results in the statistical model from a ‘perfect storm’ of La Niña-like climate conditions and relative tropical Atlantic warmth.
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ArticleSeismic evidence of glacial-age river incision into the Tahaa barrier reef, French Polynesia(Elsevier, 2016-04-13) Toomey, Michael R. ; Woodruff, Jonathan D. ; Donnelly, Jeffrey P. ; Ashton, Andrew D. ; Perron, J. TaylorRivers have long been recognized for their ability to shape reef-bound volcanic islands. On the time-scale of glacial–interglacial sea-level cycles, fluvial incision of exposed barrier reef lagoons may compete with constructional coral growth to shape the coastal geomorphology of ocean islands. However, overprinting of Pleistocene landscapes by Holocene erosion or sedimentation has largely obscured the role lowstand river incision may have played in developing the deep lagoons typical of modern barrier reefs. Here we use high-resolution seismic imagery and core stratigraphy to examine how erosion and/or deposition by upland drainage networks has shaped coastal morphology on Tahaa, a barrier reef-bound island located along the Society Islands hotspot chain in French Polynesia. At Tahaa, we find that many channels, incised into the lagoon floor during Pleistocene sea-level lowstands, are located near the mouths of upstream terrestrial drainages. Steeper antecedent topography appears to have enhanced lowstand fluvial erosion along Tahaa's southwestern coast and maintained a deep pass. During highstands, upland drainages appear to contribute little sediment to refilling accommodation space in the lagoon. Rather, the flushing of fine carbonate sediment out of incised fluvial channels by storms and currents appears to have limited lagoonal infilling and further reinforced development of deep barrier reef lagoons during periods of highstand submersion.
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PreprintA decadally-resolved paleohurricane record archived in the late Holocene sediments of a Florida sinkhole( 2011-07) Lane, D. Philip ; Donnelly, Jeffrey P. ; Woodruff, Jonathan D. ; Hawkes, Andrea D.A 4500-year record of hurricane-induced storm surges is developed from sediment cores collected from a coastal sinkhole near Apalachee Bay, Florida. Recent deposition of sand layers in the upper sediments of the pond was found to be contemporaneous with significant, historic storm surges at the site modeled using SLOSH and the Best Track, post-1851 A.D. dataset. Using the historic portion of the record for calibration, paleohurricane deposits were identified by sand content and dated using radiocarbon-based age models. Marine-indicative foraminifera, some originating at least 5 km offshore, were present in several modern and ancient storm deposits. The presence and long-term preservation of offshore foraminifera suggest that this site and others like it may yield promising microfossil-based paleohurricane reconstructions in the future. Due to the sub-decadal (~ 7 year) resolution of the record and the site’s high susceptibility to hurricane-generated storm surges, the average, local frequency of recorded events, approximately 3.9 storms per century, is greater than that of previously published paleohurricane records from the region. The high incidence of recorded events permitted a time series of local hurricane frequency during the last five millennia to be constructed. Variability in the frequency of the largest storm layers was found to be greater than what would likely occur by chance alone, with intervals of both anomalously high and low storm frequency identified. However, the rate at which smaller layers were deposited was relatively constant over the last five millennia. This may suggest that significant variability in hurricane frequency has occurred only in the highest magnitude events. The frequency of high magnitude events peaked near 6 storms per century between 2800 and 2300 years ago. High magnitude events were relatively rare with about 0-3 storms per century occurring between 1900 to 1600 years ago and between 400 to 150 years ago. A marked decline in the number of large storm deposits, which began around 600 years ago, has persisted through present with below average frequency over the last 150 years when compared to the preceding five millennia.
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Article1,050 years of hurricane strikes on Long Island in the Bahamas(American Geophysical Union, 2016-02-16) Wallace, Elizabeth J. ; Donnelly, Jeffrey P. ; van Hengstum, Peter J. ; Winkler, Tyler S. ; McKeon, Kelly ; MacDonald, Dana ; D'Entremont, Nicole ; Sullivan, Richard M. ; Woodruff, Jonathan D. ; Hawkes, Andrea D. ; Maio, Christopher V.Sedimentary records of past hurricane activity indicate centennial-scale periods over the past millennium with elevated hurricane activity. The search for the underlying mechanism behind these active hurricane periods is confounded by regional variations in their timing. Here, we present a new high resolution paleohurricane record from The Bahamas with a synthesis of published North Atlantic records over the past millennium. We reconstruct hurricane strikes over the past 1,050 years in sediment cores from a blue hole on Long Island in The Bahamas. Coarse-grained deposits in these cores date to the close passage of seven hurricanes over the historical interval. We find that the intensity and angle of approach of these historical storms plays an important role in inducing storm surge near the site. Our new record indicates four active hurricane periods on Long Island that conflict with published records on neighboring islands (Andros and Abaco Island). We demonstrate these three islands do not sample the same storms despite their proximity, and we compile these reconstructions together to create the first regional compilation of annually resolved paleohurricane records in The Bahamas. Integrating our Bahamian compilation with compiled records from the U.S. coastline indicates basin-wide increased storminess during the Medieval Warm Period. Afterward, the hurricane patterns in our Bahamian compilation match those reconstructed along the U.S. East Coast but not in the northeastern Gulf of Mexico. This disconnect may result from shifts in local environmental conditions in the North Atlantic or shifts in hurricane populations from straight-moving to recurving storms over the past millennium.
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PreprintExploring typhoon variability over the mid-to-late Holocene : evidence of extreme coastal flooding from Kamikoshiki, Japan( 2009-01) Woodruff, Jonathan D. ; Donnelly, Jeffrey P. ; Okusu, AkikoSediment cores from two coastal lakes located on the island of Kamikoshiki in southwestern Japan (Lake Namakoike and Lake Kaiike) provide evidence for the response of a backbarrier beach system to episodic coastal inundation over the last 6400 years. Subbottom seismic surveys exhibit acoustically laminated, parallel to subparallel seismic reflectors, intermittently truncated by erosional unconformities. Sediment cores collected from targeted depocenters in both lakes contain finely laminated organic mud interbedded with coarse grained units, with depths of coarse deposits concurrent with prominent seismic reflectors. The timing of the youngest deposit at Kamikoshiki correlates to the most recently documented breach in the barrier during a typhoon in 1951 AD. Assuming this modern deposit provides an analog for identifying past events, paleo typhoons may be reconstructed from layers exhibiting an increase in grain-size, a break in fine-scale stratigraphy, and elevated Sr concentrations. Periods of barrier breaching are concurrent with an increase in El Niño frequency, indicating that the El Niño/Southern Oscillation has potentially played a key role in governing typhoon variability during the mid-to-late Holocene. An inverse correlation is observed between tropical cyclone reconstructions from the western North Atlantic and the Kamikoshiki site, which may indicate an oscillating pattern in tropical cyclone activity between the western Northern Atlantic and the western North Pacific, or at least between the western Northern Atlantic and regions encompassing southern Japan. The two kamikaze typhoons which contributed to the failed Mongol invasions of Japan in 1274 AD and 1281 AD occur during a period with more frequent marine-sourced deposition at the site, suggesting the events took place during a period of greater regional typhoon activity.
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ArticleHistorically unprecedented Northern Gulf of Mexico hurricane activity from 650 to 1250 CE(Nature Research, 2020-11-05) Rodysill, Jessica R. ; Donnelly, Jeffrey P. ; Sullivan, Richard M. ; Lane, D. Philip ; Toomey, Michael R. ; Woodruff, Jonathan D. ; Hawkes, Andrea D. ; MacDonald, Dana ; D'Entremont, Nicole ; McKeon, Kelly ; Wallace, Elizabeth J. ; van Hengstum, Peter J.Hurricane Michael (2018) was the first Category 5 storm on record to make landfall on the Florida panhandle since at least 1851 CE (Common Era), and it resulted in the loss of 59 lives and $25 billion in damages across the southeastern U.S. This event placed a spotlight on recent intense (exceeding Category 4 or 5 on the Saffir-Simpson Hurricane Wind Scale) hurricane landfalls, prompting questions about the natural range in variability of hurricane activity that the instrumental record is too short to address. Of particular interest is determining whether the frequency of recent intense hurricane landfalls in the northern Gulf of Mexico (GOM) is within or outside the natural range of intense hurricane activity prior to 1851 CE. In this study, we identify intense hurricane landfalls in northwest Florida during the past 2000 years based on coarse anomaly event detection from two coastal lacustrine sediment archives. We identified a historically unprecedented period of heightened storm activity common to four Florida panhandle localities from 650 to 1250 CE and a shift to a relatively quiescent storm climate in the GOM spanning the past six centuries. Our study provides long-term context for events like Hurricane Michael and suggests that the observational period 1851 CE to present may underrepresent the natural range in landfalling hurricane activity.
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ArticleTropical cyclone wind speed constraints from resultant storm surge deposition : a 2500 year reconstruction of hurricane activity from St. Marks, FL(John Wiley & Sons, 2013-08-22) Brandon, Christine M. ; Woodruff, Jonathan D. ; Lane, D. Philip ; Donnelly, Jeffrey P.Recent work suggests that the patterns of intense (≥category 3 on the Saffir-Simpson scale) hurricane strikes over the last few millennia might differ from that of overall hurricane activity during this period. Prior studies typically rely on assigning a threshold storm intensity required to produce a sedimentological overwash signal at a particular coastal site based on historical analogs. Here, we improve on this approach by presenting a new inverse-model technique that constrains the most likely wind speeds required to transport the maximum grain size within resultant storm deposits. As a case study, the technique is applied to event layers observed in sediments collected from a coastal sinkhole in northwestern Florida. We find that (1) simulated wind speeds for modern deposits are consistent with the intensities for historical hurricanes affecting the site, (2) all deposits throughout the ∼2500 year record are capable of being produced by hurricanes, and (3) a period of increased intense hurricane frequency is observed between ∼1700 and ∼600 years B.P. and decreased intense storm frequency is observed from ∼2500 to ∼1700 and ∼600 years B.P. to the present. This is consistent with prior reconstructions from nearby sites. Changes in the frequency of intense hurricane strikes may be related to the degree of penetration of the Loop Current in the Gulf of Mexico.