Jason Ortegren

ABSTRACT We reconstructed tupelo honey yield-per-hive from AD 1800 to 2010 using tree-ring data from the long-lived nectar-source species, Nyssa ogeche. The composite N. ogeche radial growth chronology and honey yield-per-hive were significantly correlated (r = 0.556; α = 0.009; n = 21), suggesting optimal growth conditions are coincident with increased nectar production and that tree-ring data can be used to reconstruct crop history. Tupelo honey yield-per-hive has oscillated between multidecadal-length periods of low and high yields during the past 211 years and is associated with the Atlantic Multidecadal Oscillation (AMO). The expansion of the honey record suggests that the current decline is within the natural range of variability prior to record-keeping. Multidecadal-length variations in tupelo honey yield illustrate how naturally occurring climatic cycles affect crop productivity beyond the length of high-quality agricultural yield records and may offer additional information to better understand interactions between oceanic and atmospheric climate drivers, non-climatic anthropogenic impacts, and yield variability.

ABSTRACT Droughts and landfalling tropical cyclones (TCs; tropical depressions, tropical storms, and hurricanes) are important features of the hydroclimate of the southeastern USA at seasonal, interannual, and interdecadal scales. The societal impacts and climatological aspects of both droughts and Atlantic TCs have been widely addressed in the scientific literature. However, in general, previous research has assessed the two phenomena separately. Recently, the spatiotemporal patterns and hydroclimatic impacts of drought amelioration by landfalling TCs have been analyzed for the southeastern USA, as well as the large-scale dynamic forcing mechanisms that enhance or suppress drought-TC co-occurrence. At multidecadal time scales, both droughts and TCs in this region vary in association with several leading modes of basin-wide and regional climate variability. These climate modes appear to be coherently linked to a background oceanic–atmospheric pattern that either promotes or suppresses the likelihood of both droughts and TC landfalls. The relative frequency of TC landfalls in drought-stricken areas, the importance of these events in the regional moisture budget, and the potential for future changes in the large-scale forcing environment raise fundamental questions about possible changes in the hydroclimate of the southeastern USA, where population growth and rising water demand already place strain on freshwater resources. In this article, we provide a review and synthesis of the recent research on variability in drought, landfalling TCs, the characteristics of the space–time association between these two phenomena in the southeastern USA, and the coherent large-scale oceanic–atmospheric environment that either promotes or suppresses their co-occurrence. Further, we review Global Climate Model projections related to these factors, and we identify avenues for future research on this important topic.

We present a new method for identifying historic tropical cyclone activity utilizing frequencies of intra-annual density fluctuations in longleaf pine in western Florida. In addition, in this work we provide information about the causal factors that determine the formation of intraannual density fluctuations (IADFs) in longleaf pine latewood. Specifically, we test the viability of using late latewood (L+) IADFs in longleaf pine as a proxy for historic tropical cyclone frequency and precipitation for the period 1950−2017. The stabilized frequency of L+ IADF occurrence is significantly (p < 0.01) associated with the Palmer drought severity index (PDSI) for the months June through October, indicating that high amounts of late growing-season moisture promote the formation of IADFs in latewood. We find the strongest relationships between PDSI and IADF occurrence during September and October, indicating the influence of tropical cyclone (TC)-sourced precipitation on IADF formation. High IADF stabilized frequencies (i.e. >0.50) nearly always (88%) coincide with a TC tracking into the study area, and we find a significant (p < 0.01) relationship between TC-sourced precipitation and the stabilized frequency of L+ IADFs. Via this relationship, reconstruction of historic tropical cyclone frequency and precipitation is probable, which would allow for increased understanding of historic tropical cyclone activity prior to the historic climate record.

We present a new method for identifying historic tropical cyclone activity utilizing frequencies of intra-annual density fluctuations in longleaf pine in western Florida. In addition, in this work we provide information about the causal factors that determine the formation of intraannual density fluctuations (IADFs) in longleaf pine latewood. Specifically, we test the viability of using late latewood (L+) IADFs in longleaf pine as a proxy for historic tropical cyclone frequency and precipitation for the period 1950−2017. The stabilized frequency of L+ IADF occurrence is significantly (p < 0.01) associated with the Palmer drought severity index (PDSI) for the months June through October, indicating that high amounts of late growing-season moisture promote the formation of IADFs in latewood. We find the strongest relationships between PDSI and IADF occurrence during September and October, indicating the influence of tropical cyclone (TC)-sourced precipitation on IADF formation. High IADF stabilized frequencies (i.e. >0.50) nearly always (88%) coincide with a TC tracking into the study area, and we find a significant (p < 0.01) relationship between TC-sourced precipitation and the stabilized frequency of L+ IADFs. Via this relationship, reconstruction of historic tropical cyclone frequency and precipitation is probable, which would allow for increased understanding of historic tropical cyclone activity prior to the historic climate record.

We analyzed summertime (June–August) cold-front activity via frequency and duration in the southeastern USA during 1973–2020 to summarize and identify the temporal trends of the annual and total number of hours associated with cold fronts, cold-front days, and multi-day cold-front events. Using data from 34 ASOS Network stations, we defined summertime cold fronts as events that lowered the dew point temperature below 15.56 °C (< 60 °F). Additionally, we examined 500 hPa geopotential height anomalies associated with years with cold front frequency/duration deviations of +/− 1.0 SD. The extent of the cold-front activity exhibited a north–south latitudinal gradient with a more southerly latitudinal expression on the east side of the Appalachian Mountains and was negligible south of the 30°N latitude. The cold-front activity was most prominent during the first half of June. Our results suggest that all three metrics of summertime cold-front activity were stable at a regional scale du...

Precipitation from land-falling tropical cyclones (TCs) has a significant hydroclimatic influence in the southeastern United States, particularly during drought years. The frequency with which TCs ended drought conditions was examined for southeastern coastal states fromTexas to North Carolina during 1895–2011. The region was divided into the Gulf Coast states (GCS) and the southeastern Atlantic coast states (ACS). The spatiotemporal patterns of tropical cyclone drought busters (TCDBs) were analyzed. Larger-scale ocean– atmosphere influences on TCDBs were examined using chi-squared analysis. The ACS experienced TCDBs more frequently and farther inland compared to the GCS. The number of TCDBs has significantly increased with time in theACS. TCDBs numbers in theGCS did not exhibit significant increases, but the area alleviated of drought conditions increased significantly in the last 117 years. The dominant larger-scale ocean–atmosphere forcing of TCDBswas a combination of awarmAtlant...

From the 344 state climate divisions in the conterminous United States, nine distinct regions of warmseason drought variability are identified using principal component analysis. The drought metric used is the Palmer hydrological drought index for the period 1895-2008. The focus of this paper is multidecadal drought variability in the Southeast (SEUS) and eastern Gulf South (EGS) regions of the United States, areas in which the low-frequency forcing mechanisms of warm-season drought are still poorly understood. Low-frequency drought variability in the SEUS and EGS is associated with smoothed indexed time series of major oceanatmosphere circulation features, including two indices of spatiotemporal variability in the North Atlantic subtropical anticyclone (Bermuda high). Long-term warm-season drought conditions are significantly out of phase between the two regions. Multidecadal regimes of above-and below-average moisture in the SEUS and EGS are closely associated with slow variabilit...

From the 344 state climate divisions in the conterminous United States, nine distinct regions of warm-season drought variability are identified using principal component analysis. The drought metric used is the Palmer hydrological drought index for the period 1895–2008. The focus of this paper is multidecadal drought variability in the Southeast (SEUS) and eastern Gulf South (EGS) regions of the United States, areas in which the low-frequency forcing mechanisms of warm-season drought are still poorly understood. Low-frequency drought variability in the SEUS and EGS is associated with smoothed indexed time series of major ocean– atmosphere circulation features, including two indices of spatiotemporal variability in the North Atlantic subtropical anticyclone (Bermuda high). Long-term warm-season drought conditions are significantly out of phase between the two regions. Multidecadal regimes of above- and below-average moisture in the SEUS and EGS are closely associated with slow variab...

This paper investigates the differences in temperature trends during a 40-year period in urbanized and urbanizing areas in North Carolina. Urbanized sites are in the urban cores of the selected regions; urbanizing sites are in outlying suburban locations characterized by lower devel-opment intensities than their respective urban cores. We examined maximum and minimum

This paper investigates the differences in temperature trends during a 40-year period in urbanized and urbanizing areas in North Carolina. Urbanized sites are in the urban cores of the selected regions; urbanizing sites are in outlying suburban locations characterized by lower development intensities than their respective urban cores. We examined maximum and minimum temperatures for four seasons represented by the months of March, June, September, and December. This study shows that the heavily urbanized downtown areas did not exhibit significant increasing trend in temperatures. Rather, the significant increases in temperatures occurred in suburban areas that experienced varying degrees of urbanization during the past 40 years. We conclude that although some urbanized areas may have higher temperatures than areas in their surrounding regions, urbanizing locations outside of central cities may be closing that gap, possibly due to the process of urbanization.

The development of summer drought reconstructions for 12 Piedmont and Coastal Plain climate divisions in the southeastern U.S. from existing and original tree-ring chronologies is described. The drought metric reconstructed is the Palmer Meteorological Drought Index (PMDI), a modification of the Palmer Drought Severity Index (PDSI). A composite chronology of average yearly growth index values from individual chronologies covers the common period 1690-1984. The reconstructions have been tested for validity using PMDI data not included in regression modeling. The reconstructions included 6 periods of sustained (> 4 yr) summer drought in the study area during the period 1690-1900. The instrumental record (1900-2006) contains 5 such droughts. Two periods of multi-year summer drought more severe than any in the observed record were found in the reconstructions, the most recent of which ended around 1821. After 1900, prolonged summer droughts in the Piedmont exhibited similar severity ...

Tropical cyclones (TCs) are an important source of precipitation for much of the eastern United States. However, our understanding of the spatiotemporal variability of tropical cyclone precipitation (TCP) and the connections to large-scale atmospheric circulation is limited by irregularly distributed rain gauges and short records of satellite measurements. To address this, we developed a new gridded (0.25° x 0.25°) publicly available dataset of TCP (1948–2015; Tropical Cyclone Precipitation Dataset, or TCPDat) using TC tracks to identify TCP within an existing gridded precipitation dataset. TCPDat was used to characterize total June–November TCP and percent contribution to total June–November precipitation. TCP totals and contributions had maxima on the Louisiana, North Carolina, and Texas coasts, substantially decreasing farther inland at rates of approximately 6.2 to 6.7 mm km-1. Few statistically significant trends were discovered in either TCP totals or percent contribution. TCP...

The Florida Department of Health, Environmental Public Health Tracking Program, in collaboration with the
Escambia County Health Department and the University of West Florida, used the Health Impact Assessment Framework to examine adverse health outcomes that may be related to an extreme flood event in Pensacola, Florida (Escambia County) during April 29 to May 3, 2014. In this 2014 flood event, portions of Pensacola received more than 15.5 in of rain in a single
day. Infrastructure impacts from this extreme event included destroyed bridges and roads and the failure of many sewage lift stations.

Objective: To determine whether there were associated increases in injury, illness, and death, data on reportable diseases, hospitalizations, emergency department (ED) visits, and deaths that occurred during the impact period in 2014 were compared with a control period in 2008.

Design: We used an ecological design to compare impact and control periods and examined the proportion of hospitalizations, ED visits, and deaths potentially attributable to the extreme flood event.

Results: The results of this comparison were mixed, with some Escambia County zip codes showing increased hospitalizations and ED visits, and some zip codes showing a decrease. However, countywide, there were increases in the proportion of both injury- and respiratory-related hospitalizations and ED visits during the impact period.

Conclusions: It is challenging to characterize human health impacts from natural disasters such as extreme floods. Still, it is believed that specific policy changes could result in fewer health impacts during future flood events. For example, this study recommended raising the electric panels on lift stations above the flood elevation to keep them operational during extreme rainfall events. For more maps and tables, consult the complete project report available online at http://
www.floridatracking.com/HealthTrackFL/document/Escambia_HIA_Report.pdf.

We present a new method for identifying historic tropical cyclone activity utilizing
frequencies of intra-annual density fluctuations in longleaf pine in western Florida. In addition, in this work we provide information about the causal factors that determine the formation of intraannual density fluctuations (IADFs) in longleaf pine latewood. Specifically, we test the viability of using late latewood (L+) IADFs in longleaf pine as a proxy for historic tropical cyclone frequency and precipitation for the period 1950−2017. The stabilized frequency of L+ IADF occurrence is significantly
(p < 0.01) associated with the Palmer drought severity index (PDSI) for the months June through October, indicating that high amounts of late growing-season moisture promote the formation of IADFs in latewood. We find the strongest relationships between PDSI and IADF occurrence during September and October, indicating the influence of tropical cyclone (TC)-sourced precipitation on IADF formation. High IADF stabilized frequencies (i.e. >0.50) nearly always (88%) coincide with a TC tracking into the study area, and we find a significant (p < 0.01) relationship between TC-sourced precipitation and the stabilized frequency of L+ IADFs. Via this relationship,
reconstruction of historic tropical cyclone frequency and precipitation is probable, which would allow for increased understanding of historic tropical cyclone activity prior to the historic climate record.