Identifying leads and lags between high- and low-latitude abrupt climate shifts is needed to understand where and how such events were triggered. Vascular plant biomarkers preserved in Cariaco basin sediments reveal rapid vegetation changes in northern South America during the last deglaciation, 15,000 to 10,000 years ago. Comparing the biomarker records to climate proxies from the same sedimen...

ous problem on the East Coast until the 1980s, when it started killing entire populations of both wild and cultivated trees in the mid-Atlantic region. HWA is now well established in the eastern portion of the range of eastern hemlock, from New Hampshire south to North Carolina,z as well as in most of the range of Carolina hemlock (T. caroliniana). While considerable research has been directed ...

[1] We interpret the distribution of tropical tropospheric ozone columns (TTOCs) from the Total Ozone Mapping Spectrometer (TOMS) by using a global three-dimensional model of tropospheric chemistry (GEOS-CHEM) and additional information from in situ observations. The GEOS-CHEM TTOCs capture 44% of the variance of monthly mean TOMS TTOCs from the convective cloud differential method (CCD) with n...

[1] Observational analyses suggest that the northern North Atlantic is fresher in the late 20th century in comparison to the 1950–60s. Here we examine possible contributors to these observed changes by analyzing a four-member ensemble of 20th century simulations from a coupled climate model. Results show that a weaker meridional freshwater divergence related to a weaker thermohaline circulation...

The European Alps are an effective barrier for meridional moisture transport and are thus uniquely placed to record shifts in the North Atlantic storm track pattern associated with the waxing and waning of Late-Pleistocene Northern Hemisphere ice sheets. The lack of well-dated terrestrial proxy records spanning this time period, however, renders the reconstruction of past atmospheric patterns d...

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...

Titanium and iron concentration data from the anoxic Cariaco Basin, off the Venezuelan coast, can be used to infer variations in the hydrological cycle over northern South America during the past 14,000 years with subdecadal resolution. Following a dry Younger Dryas, a period of increased precipitation and riverine discharge occurred during the Holocene "thermal maximum." Since approximately 54...

Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those from Scandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We ...

The influence of Atlantic sea surface temperature (SST) anomalies on the atmospheric circulation over the North Atlantic sector during winter is investigated by performing experiments with an atmospheric general circulation model (GCM). These consist of a 30-year run with observed SST anomalies for the period 1961–90 confined geographically to the Atlantic Ocean, and of a control run with clima...