Multidecadal Recession of Grinnell and Terra Nivea Ice Caps, Baffin Island, Canada

Multi-temporal satellite imagery and historical aerial photography reveal that two southern Arctic ice caps on Baffin Island have shrunk considerably over the past several decades. Satellite remote sensing shows that over the past three decades, the Grinnell and Terra Nivea ice caps, the southernmost ice caps in the eastern Canadian Arctic, have decreased in area by 18% and 22% respectively, which corresponds to a total area decline of 68 km2 since the inventory done in the late 1950s. Cumulative ice loss since the mid-1970s has occurred at a rate of −1.69 km2/yr. The Grinnell ice cap has declined in area by −0.57 km2/yr, while the larger Terra Nivea ice cap has lost ice at a rate of −1.1 km2/yr. Interior thinning has led to the exposure of nunataks far from ice margins, and outlet glaciers have retreated substantial distances up-valley. The rapid reduction in ice area is linked directly to increasing summer air temperatures and suggests that these ice caps are in disequilibrium with current climate. Projections suggest that if the observed ice decline continues to AD 2100, the total area covered by ice at present will be reduced by more than 57%.L’imagerie satellitaire multitemporelle et la photographie aérienne historique révèlent que deux calottes glaciaires du sud de l’Arctique, dans l’île de Baffin, ont rétréci considérablement au cours des dernières décennies. La télédétection par satellite montre qu’au cours des trois dernières décennies, l’étendue des calottes glaciaires Grinnell et Terra Nivea, soit les calottes glaciaires les plus au sud de l’Arctique canadien de l’est, a diminué dans une mesure de 18 % et de 22 % respectivement, ce qui correspond à un déclin total de l’étendue de 68 km2 depuis que l’inventaire a été dressé vers la fin des années 1950. Depuis le milieu des années 1970, la perte cumulative de glace s’est produite au taux de −1,69 km2/an. L’étendue de la calotte glaciaire Grinnell a diminué de −0,57 km2/an, tandis que la calotte glaciaire Terra Nivea, dont l’étendue est plus grande, a enregistré une perte de glace de l’ordre de −1,1 km2/an. L’amincissement intérieur a donné lieu à l’exposition de nunataks loin des marges glaciaires, et les glaciers émissaires ont reculé sur d’importantes distances en amont de la vallée. La réduction rapide de l’étendue de la glace est directement liée à l’augmentation de la température de l’air d’été, ce qui suggère que ces calottes glaciaires sont en déséquilibre par rapport au climat actuel. Selon les projections, si la réduction observée de la glace se poursuit jusqu’en l’an 2100 A.D., l’étendue totale actuellement couverte par la glace diminuera de plus de 57 %

Record Size Female Coyote, Canis latrans

On 11 March 2004 we recaptured and re-radio-collared an 8-9 yr old, 25.1 kg (55.3 lb), 157 cm long (tip of nose to tail tip) female Eastern Coyote (Canis latrans) in the town of Barnstable on Cape Cod, Massachusetts, that was originally captured in November 1998. This is believed to be the largest female Coyote ever recorded

A METHOD FOR ASSESSING BLACKBIRD DAMAGE TO RIPENING RICE

A method for measuring and mapping the location of blackbird (Icterinae) damage to ripening rice over time was developed and employed in 7 commercial rice fields ranging from 20.6 to 47.4 ha in Matagorda County, Texas, during the 1985 and 1986 growing seasons. Ten evenly-spaced transects were established perpendicular to the longest side of the field and each transect was sampled at pre-determined distances. Transects were subdivided into edge (\u3c= 60 m from field border) and middle (\u3e 60 m from the field border) strata. The measured percent damage was compared to visual estimates for 3 samplings to assess the accuracy and precision of the latter. Measuring the percent damage to individual panicles appears to be valid, but damage may be underestimated. This sampling method may be useful for assessing the efficacy of current and proposed damage control techniques. Visual estimates were too high at low (\u3c 5%) damage levels and too low at higher (\u3e 5%) levels compared to measured damage

A Method for Assessing Blackbird Damage to Ripening Rice

A method for measuring and mapping the location of blackbird (Icterinae) damage to ripening rice over time was developed and employed in 7 commercial rice fields ranging from 20.6 to 47.4 ha in Matagorda County, Texas, during the 1985 and 1986 growing seasons. Ten evenly-spaced transects were established perpendicular to the longest side of the field and each transect was sampled at pre-determined distances. Transects were subdivided into edge ( \u3c = 60 m from field border) and middle ( \u3e 60 m from the field border) strata. The measured percent damage was compared to visual estimates for 3 samplings to assess the accuracy and precision of the latter. Measuring the percent damage to individual panicles appears to be valid, but damage may be underestimated. This sampling method may be useful for assessing the efficacy of current and proposed damage control techniques. Visual estimates were too high at low ( \u3c 5%) damage levels and too low at higher ( \u3e 5%) levels compared to measured damage

Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada)

The Torngat Mountains National Park, northern Labrador, Canada, contains more than 120 small glaciers: the only remaining glaciers in continental northeast North America. These small cirque glaciers exist in a unique topo-climatic setting, experiencing temperate maritime summer conditions yet very cold and dry winters, and may provide insights into the deglaciation dynamics of similar small glaciers in temperate mountain settings. Due to their size and remote location, very little information exists regarding the health of these glaciers. Just a single study has been published on the contemporary glaciology of the Torngat Mountains, focusing on net mass balances from 1981 to 1984. This paper addresses the extent to which glaciologically relevant climate variables have changed in northern Labrador in concert with 20th-century Arctic warming, and how these changes have affected Torngat Mountain glaciers. Field surveys and remote-sensing analyses were used to measure regional glacier area loss of 27 % from 1950 to 2005, substantial rates of ice surface thinning (up to 6 m yr⁻¹) and volume losses at Abraham, Hidden, and Minaret glaciers, between 2005 and 2011. Glacier mass balances appear to be controlled by variations in winter precipitation and, increasingly, by strong summer and autumn atmospheric warming since the early 1990s, though further observations are required to fully understand mass balance sensitivities. This study provides the first comprehensive contemporary assessment of Labrador glaciers and will inform both regional impact assessments and syntheses of global glacier mass balance

Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends

Incomplete global coverage is a potential source of bias in global temperature reconstructions if the unsampled regions are not uniformly distributed over the planet's surface. The widely used Hadley Centre-Climatic Reseach Unit Version 4 (HadCRUT4) dataset covers on average about 84% of the globe over recent decades, with the unsampled regions being concentrated at the poles and over Africa. Three existing reconstructions with near-global coverage are examined, each suggesting that HadCRUT4 is subject to bias due to its treatment of unobserved regions. Two alternative approaches for reconstructing global temperatures are explored, one based on an optimal interpolation algorithm and the other a hybrid method incorporating additional information from the satellite temperature record. The methods are validated on the basis of their skill at reconstructing omitted sets of observations. Both methods provide results superior to excluding the unsampled regions, with the hybrid method showing particular skill around the regions where no observations are available. Temperature trends are compared for the hybrid global temperature reconstruction and the raw HadCRUT4 data. The widely quoted trend since 1997 in the hybrid global reconstruction is two and a half times greater than the corresponding trend in the coverage-biased HadCRUT4 data. Coverage bias causes a cool bias in recent temperatures relative to the late 1990s, which increases from around 1998 to the present. Trends starting in 1997 or 1998 are particularly biased with respect to the global trend. The issue is exacerbated by the strong El Niño event of 1997-1998, which also tends to suppress trends starting during those years

On a minimal model for estimating climate sensitivity

In a recent issue of this journal, Loehle (2014) presents a "minimal model" for estimating climate sensitivity, identical to that previously published by Loehle and Scafetta (2011). The novelty in the more recent paper lies in the straightforward calculation of an estimate of transient climate response based on the model and an estimate of equilibrium climate sensitivity derived therefrom, via a flawed methodology. We demonstrate that the Loehle and Scafetta model systematically underestimates the transient climate response, due to a number of unsupportable assumptions regarding the climate system. Once the flaws in Loehle and Scafetta's model are addressed, the estimates of transient climate response and equilibrium climate sensitivity derived from the model are entirely consistent with those obtained from general circulation models, and indeed exclude the possibility of low climate sensitivity, directly contradicting the principal conclusion drawn by Loehle. Further, we present an even more parsimonious model for estimating climate sensitivity. Our model is based on observed changes in radiative forcings, and is therefore constrained by physics, unlike the Loehle model, which is little more than a curve-fitting exercise

Northern Hemisphere permafrost map based on TTOP modelling for 2000-2016 at 1 km²scale

Permafrost is a key element of the cryosphere and an essential climate variable in the Global Climate Observing System. There is no remote-sensing method available to reliably monitor the permafrost thermal state. To estimate permafrost distribution at a hemispheric scale, we employ an equilibrium state model for the temperature at the top of the permafrost (TTOP model) for the 2000–2016 period, driven by remotely-sensed land surface temperatures, down-scaled ERA-Interim climate reanalysis data, tundra wetness classes and landcover map from the ESA Landcover Climate Change Initiative (CCI) project. Subgrid variability of ground temperatures due to snow and landcover variability is represented in the model using subpixel statistics. The results are validated against borehole measurements and reviewed regionally. The accuracy of the modelled mean annual ground temperature (MAGT) at the top of the permafrost is ±2 °C when compared to permafrost borehole data. The modelled permafrost area (MAGT 0) is around 21 × 106 km2 (22% of exposed land area), which is approximately 2 × 106 km2 less than estimated previously. Detailed comparisons at a regional scale show that the model performs well in sparsely vegetated tundra regions and mountains, but is less accurate in densely vegetated boreal spruce and larch forests