[1] Recent historical Northern Hemisphere (NH) tropical cyclone (TC) inactivity is compared with strikingly large observed variability during the past three decades. Yearly totals of the combined active-basin NH accumulated cyclone energy (ACE) are highly correlated with boreal spring seasurface temperature (SST) in the North Pacific Ocean and are representative of an evolving dual-gyre, trans-...

Four regional Scots pine ring-width chronologies at the northern forest-limit, and in the northern, middle and southern boreal forest belts in Finland cover the last fourteen centuries. Tree-ring statistics and response functions were examined, and tree-ring width variation was also compared to North Atlantic Oscillation (NAO) and volcanic forcing. The tree-ring statistics show evidence of an e...

[1] Aircraft flying through cold ice-supersaturated air produce persistent contrails which contribute to the climate impact of aviation. Here, we demonstrate the importance of the weather situation, together with the route and altitude of the aircraft through this, on estimating contrail coverage. The results have implications for determining the climate impact of contrails as well as potential...

The European green crab, Carcinus maenas, has a native distribution that extends from Norway to Mauritania. It has attracted attention because of its recent invasions of Australia, Tasmania, South Africa, Japan and both coasts of North America. To examine the population structure of this global invader in its native range, we analysed a 502-base-pair fragment of the mitochondrial cytochrome c o...

The ecological and conservation status of the geographically isolated Black Sea harbour porpoise is currently unknown. Although it has been suggested that Black Sea harbour porpoises are distinct from other populations, the implementation of specific conservation plans has been hindered by the absence of a genetic and morphological study with large sample sizes. We sought to test the hypothesis...

Droughts in the Southern Great Plains (SGP) have been attributed to the cold phase of El Niño–Southern Oscillation or La Niña. While La Niña events have been clearly linked to winter droughts, their link to summer droughts has remained unclear. We analyze the difference in precipitation between dry and nondry summers over the SGP during La Niña years. Anomalously high geopotential height and su...

Air-water exchange gradients of selected polychlorinated biphenyl (PCB) congeners across a large section of the tropical Atlantic suggested net volatilization of PCBs to the atmosphere. Only for the higher chlorinated PCB 153 and hexachlorobenzene (HCB) were gradients near equilibrium detected. The use of passive samplers also enabled the detection of dichlorodiphenyltrichloroethane (DDT) and i...

A tangent linear adjoint for a low-resolution dynamical model of the atmosphere is used to derive the optimal forcing perturbations for all state variables such that after a specified lead time the model response has a given projection, in terms of an energy norm, on the pattern associated with the 51-yr trend in the Northern Hemisphere winter tropospheric circulation, 1948/49–1998/99. A featur...