Storm Surge, Blocking, and Cyclones: A Compound Hazards Analysis for the Northeast United States

Storm surge is a weather hazard that can generate dangerous flooding and is not fully understood in terms of timing and atmospheric forcing. Using observations along the Northeast United States, surge is sorted based on duration and intensity to reveal distinct time-evolving behavior. Long-duration surge events slowly recede, while strong, short-duration events often involve negative surge in quick succession after the maximum. Using Lagrangian track information, the tropical and extratropical cyclones and atmospheric blocks that generate the surge events are identified. There is a linear correlation between surge duration and surge maximum, and the relationship is stronger for surge caused by extratropical cyclones as compared to those events caused by tropical cyclones. For the extremes based on duration, the shortest-duration strong surge events are caused by tropical cyclones, while the longest-duration events are most often caused by extratropical cyclones. At least half of long-duration surge events involve anomalously strong atmospheric blocking poleward of the cyclone, while strong, short-duration events are most often caused by cyclones in the absence of blocking. The dynamical influence of the blocks leads to slow-moving cyclones that take meandering paths. In contrast, for strong, short-duration events, cyclones travel faster and take a more meridional path. These unique dynamical scenarios provide better insight for interpreting the threat of surge in medium-range forecasts.

Range contractions of the Broad-winged Hawk in the Northeast United States

The Broad-winged Hawk (BWHA, Buteo platypterus) is a small, secretive hawk with distinguishing broad black tail bands that breeds in northeastern North America. The hawk nests in deciduous or mixed forest, often near water, and close to clearings or forest edges. Land conversion and fragmentation alters the landscape and reduces the area of contiguous forest used by BWHA. This study seeks to determine the landscape characteristics influencing the apparent breeding range declines of the BWHA at the landscape scale. Landscape characteristics and BWHA presence data from 18,684 Breeding Bird Atlas blocks (each about 25km2) from Ohio, West Virginia, Maryland, Pennsylvania, and New York for two atlas period (1st Atlas: 1980s, 2nd Atlas: 2000s) were analyzed. Bayesian latent Gaussian models were fitted using INLA to determine best fit model for predicting the landscape characteristics associated with BWHA presence. The best models included landscape changes in land cover, including forest, water, urban, barren, farmland, and wetland and fragmentation of the landscape. Trends in loss were especially prevalent around the region's largest cities: New York, Philadelphia, Baltimore and Washington DC. Loss of BWHA at the block-level was associated with areas with less forest in the 2000s, a decline in size of largest forest patches, lower elevations and lower latitudes. We suggest that both habitat loss and climate change may be contributing to the range contraction of the Broad-winged Hawk in the northeast United States.

Ascertaining the initiation of epidemic resurgences: an application to the COVID-19 second surges in Europe and the Northeast United States

Assessing a potential resurgence of an epidemic outbreak with certainty is as important as it is challenging. The low number of infectious individuals after a long regression, and the randomness associated with it, makes it difficult to ascertain whether the infectious population is growing or just fluctuating. We have developed an approach to compute confidence intervals for the switching time from decay to growth and to compute the corresponding multiple-location aggregated quantities over a region to increase the precision of the determination. We estimated the aggregate prevalence over time for Europe and the northeast United States to characterize the COVID-19 second surge in these regions during year 2020. We find a starting date as early as 3 July (95% confidence interval (CI): 1–6 July) for Europe and 19 August (95% CI: 16–23 August) for the northeast United States; subsequent infectious populations that, as of 31 December, have always increased or remained stagnant; and the resurgences being the collective effect of each overall region with no location, either country or state, dominating the regional dynamics by itself.