Recent marginal changes of the Mittivakkat Glacier,Southeast Greenland and the discovery of remains of reindeer (Rangifer tarandus), polar bear (Ursus maritimus) and peaty material

Geografisk Tidsskrift, Danish Journal of Geography 108(1):137–142, 2008

During field observations in August 2005 antler remains of a reindeer were found at a recently deglaciated site at about 500 m asl., and bones from a polar bear were found at about 300 m asl. along the margin of Mittivakkat Glacier, Southeast Greenland. Radio carbon dating determined the age of the samples to 720 ¹⁴C years and 350 ¹⁴C years, respectively. In August 2006 old surface vegetation covering peaty material became exposed due to ice recession close to the site where the antler was found. The radio carbon age of small roots from the material was determined to 1530 ¹⁴C years, and is in agreement with dating of woody remains of Salix glauca found close by, at the top of a nearby nunatak in 1999. The antler indicates that reindeer lived in the area when the glacier began to advance from a position where it was close to or smaller than today. The vegetation surface and peaty material indicate that the climate was warmer before the onset of the Little Ice Age in Southeast Greenland than today.     

The Emergence of Standardized,Idealized, and Placeless Landscapes in Midwestern Main Street Postcards

Although Main Streets line small towns from Florida to Alaska, Main Street is more than just a street name; it is a place imbued with local pride, regional identity, and national virtues. This symbolic connection derives from the Midwestern Main Streets of the first half of the twentieth century, a time that coincides with the golden age of the picture postcard. This article explores how the connotative and denotative symbols from this golden age overlap. A sample of 140 postcards from small towns in Kansas and Nebraska with a viable Main Street from 1900 to 1945 was selected from books, personal collections, and Internet auction sites. Our discovery of a disconnect between picture postcard and reality was not surprising, but there was a shift from the significance of basic denotative signs and the particularities of individual Main Streets in the early part of the twentieth century to an increased importance of connotative signs unifying a homogeneous Main Street ideal. Three distinct eras of postcard manipulation emerged from the data: A slightly manipulated 1900–1911 era, a 1912–1930 era emphasizing a corridor of progress, and a 1931–1945 era that displayed a growing detachment from reality and moved from the unique characteristics of a particular town toward a homogenized and idealized “Main Street view.” This article offers empirical evidence for the theoretical propositions of humanist and critical geographers that the representations of the American landscape are becoming increasingly homogenized, contrived, and placeless.     

A case study of the mesoscale dynamics in the North-Western Mediterranean Sea: a combined data–model approach

The Northern current is the main circulation feature of the North-Western Mediterranean Sea. While the large-scale to mesoscale variability of the northern current (NC) is well known and widely documented for the Ligurian region, off Nice or along the Gulf of Lions shelf, few is known about the current instabilities and its associated mesoscale dynamics in the intermediate area, off Toulon. Here, we took advantage of an oceanographic cruise of opportunity, the start of a HF radar monitoring programme in the Toulon area and the availability of regular satellite sea surface temperature and chlorophyll a data, to evaluate the realism of a NEMO-based regional high-resolution model and the added value brought by HF radar. The combined analysis of a 1/64° configuration, named GLAZUR64, and of all data sets revealed the occurrence of an anticyclonic coastal trapped eddy, generated inside a NC meander and passing the Toulon area during the field campaign. We show that this anticyclonic eddy is advected downstream along the French Riviera up to the study region and disturbs the Northern current flow. This study aims to show the importance of combining observations and modelling when dealing with mesoscale processes, as well as the importance of high-resolution modelling.     

Geochemistry of groundwater in front of a warm‐based glacier in Southeast Greenland

Groundwater in front of warm‐based glaciers is likely to become a more integrated part of the future proglacial hydrological system at high latitudes due to global warming. Here, we present the first monitoring results of shallow groundwater chemistry and geochemical fingerprinting of glacier meltwater in front of a warm‐based glacier in Southeast Greenland (Mittivakkat Gletscher, 65° 41′ N, 37° 48′ W). The groundwater temperature, electrical conductivity and pressure head were monitored from August 2009 to August 2011, and water samples were collected in 2009 and analyzed for major ions and water isotopes (δD, δ¹⁸O). The 2 yrs of monitoring revealed that major outbursts of glacier water during the ablation season flushed the proglacial aquifer and determined the groundwater quality for the next 2–8 weeks until stable chemical conditions were reached again. Water isotope composition shows that isotopic fractionation occurs in both groundwater and glacier meltwater, but fractionation due to evaporation from near‐surface soil moisture prior to infiltration has the most significant effect. This study shows that groundwater in Low Arctic Greenland is likely to possess a combined geochemical and isotopic composition, which is distinguishable from other water sources in the proglacial environment. However, the shallow groundwater composition at a given time is highly dependent on major outbursts of glacier water in the previous months.     

The Bonneville Estates Rockshelter rodent fauna and changes in Late Pleistocene–Middle Holocene climates and biogeography in the Northern Bonneville Basin,USA

Excavations at Bonneville Estates Rockshelter, Nevada recovered rodent remains from stratified deposits spanning the past ca. 12,500 ¹⁴C yr BP (14,800 cal yr BP). Specimens from horizons dating to the late Pleistocene and early Holocene include species adapted to montane and moist and cool habitats, including yellow-bellied marmot (Marmota flaviventris) and bushy-tailed woodrat (Neotoma cinerea). Shortly after 9000 ¹⁴C BP (10,200 cal yr BP) these mammals became locally extinct, or nearly so, taxonomic diversity declined, and the region became dominated by desert woodrats (Neotoma lepida) and other species well-adapted to xeric, low-elevation settings. The timing and nature of changes in the Bonneville Estates rodent fauna are similar to records reported from nearby Homestead and Camels Back caves and provide corroborative data on terminal Pleistocene–early Holocene environments and mammalian responses to middle Holocene desertification. Moreover, the presence of northern pocket gopher (Thomomys talpoides) at Bonneville Estates adds to a sparse regional record for that species and, similar to Homestead Cave, it appears that the ca. 9500 ¹⁴C yr BP (10,800 cal yr BP) replacement of the northern pocket gopher by Botta's pocket gopher in the Great Salt Lake Desert vicinity was also in response to climate change.     

It starts at home? Climate policies targeting household consumption and behavioral decisions are key to low-carbon futures

Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy.     

Submarine Groundwater Discharge-Derived Nutrient Loads to San Francisco Bay: Implications to Future Ecosystem Changes

Submarine groundwater discharge (SGD) was quantified at select sites in San Francisco Bay (SFB) from radium (²²³Ra and ²²⁴Ra) and radon (²²²Rn) activities measured in groundwater and surface water using simple mass balance box models. Based on these models, discharge rates in South and Central Bays were 0.3?C7.4?m³?day^?1?m^?1. Although SGD fluxes at the two regions (Central and South Bays) of SFB were of the same order of magnitude, the dissolved inorganic nitrogen (DIN) species associated with SGD were different. In the South Bay, ammonium (NH ₄ ⁺ ) concentrations in groundwater were three-fold higher than in open bay waters, and NH ₄ ⁺ was the primary DIN form discharged by SGD. At the Central Bay site, the primary DIN form in groundwater and associated discharge was nitrate (NO ₃ ^? ). The stable isotope signatures (??¹⁵N_NO3 and ??¹⁸O_NO3) of NO ₃ ^? in the South Bay groundwater and surface waters were both consistent with NO ₃ ^? derived from NH ₄ ⁺ that was isotopically enriched in ¹⁵N by NH ₄ ⁺ volatilization. Based on the calculated SGD fluxes and groundwater nutrient concentrations, nutrient fluxes associated with SGD can account for up to 16?% of DIN and 22?% of DIP in South and Central Bays. The form of DIN contributed to surface waters from SGD may impact the ratio of NO ₃ ^? to NH ₄ ⁺ available to phytoplankton with implications to bay productivity, phytoplankton species distribution, and nutrient uptake rates. This assessment of nutrient delivery via groundwater discharge in SFB may provide vital information for future bay ecological wellbeing and sensitivity to future environmental stressors.     

Regional Temperature Forecast for the Next Day in Hong Kong

For a century or so, the Hong Kong Observatory (HKO) has been providing temperature forecast for the whole of Hong Kong with the HKO Headquarters as the reference location. In recent decades, due to spreading of population from the main urban center to satellite towns, there is an increasing demand for regional temperature forecasts. To support such provision, the HKO has developed a regression model to provide objective guidance to forecasters in formulating forecasts of maximum and minimum temperatures for the next day at various locations in Hong Kong. In this paper, the regression model is presented, together with the assessment of its performance. Based on the verification of one year of forecasts, it is found that the root mean square errors (RMSEs) of maximum (minimum) temperature forecasts are from about 1.3 to 2.1 (1.1 to 1.4) degrees, respectively. The regression model is shown to have generally out-performed the operational regional spectral model then operated by HKO. Regional temperature forecast methods of other meteorological or research centers are also surveyed. Equipped with the regression model, the HKO has launched an online regional temperature forecast service for the next day in Hong Kong since March 2008.