Patterned ground in Southeastern Newfoundland

1968 ◽  
Vol 5 (6) ◽  
pp. 1443-1453 ◽  
Author(s):  
E. P. Henderson

Patterned ground is present and active on the Avalon Peninsula of Newfoundland, though in the main it is restricted to higher exposed areas of the southern half of that peninsula. The patterned ground forms resemble types previously considered confined, if at low elevations, to more northerly latitudes. Also, a permafrost base had been assumed necessary for construction of certain of the structures, but there presently is no permafrost anywhere on the Avalon Peninsula. Formation of the patterned ground was caused largely by low summer temperatures, general thinness or absence of snow cover in winter, and a strongly maritime climate. Those factors, where combined with sparse vegetation and a hard till underlying the frost-churned soils, can produce most typical patterned ground forms.Presence of such well-developed features on the Avalon Peninsula indicates that fossil frost structures elsewhere should not everywhere be assumed to indicate much more severe climate, perhaps with permafrost, in the past. They may merely indicate an earlier, intensely maritime-type climate with a moderate winter, but a low mean, annual temperature.

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 728
Author(s):  
Xuejiao Wu ◽  
Yongping Shen ◽  
Wei Zhang ◽  
Yinping Long

With snow cover changing worldwide in several worrisome ways, it is imperative to determine both the variability in snow cover in greater detail and its relationship with ongoing climate change. Here, we used the satellite-based snow cover extent (SCE) dataset of National Oceanic and Atmospheric Administration (NOAA) to detect SCE variability and its linkages to climate over the 1967–2018 periods across the Northern Hemisphere (NH). Interannually, the time series of SCE across the NH reveal a substantial decline in both spring and summer (−0.54 and −0.71 million km2/decade, respectively), and this decreasing trend corresponded with rising spring and summer temperatures over high-latitude NH regions. Among the four seasons, the temperature rise over the NH was the highest in winter (0.39 °C/decade, p < 0.01). More precipitation in winter was closely related to an increase of winter SCE in mid-latitude areas of NH. Summer precipitation over the NH increased at a significant rate (1.1 mm/decade, p < 0.01), which likely contribute to the accelerated reduction of summer’s SCE across the NH. However, seasonal sensitivity of SCE to temperature changes differed between the Eurasian and North American continents. Thus, this study provides a better understanding of seasonal SCE variability and climatic changes that occurred at regional and hemispheric spatial scales in the past 52 years.


2021 ◽  
Vol 13 (9) ◽  
pp. 1843
Author(s):  
Xiaona Chen ◽  
Yaping Yang ◽  
Yingzhao Ma ◽  
Huan Li

Snow cover phenology has exhibited dramatic changes in the past decades. However, the distribution and attribution of the hemispheric scale snow cover phenology anomalies remain unclear. Using satellite-retrieved snow cover products, ground observations, and reanalysis climate variables, this study explored the distribution and attribution of snow onset date, snow end date, and snow duration days over the Northern Hemisphere from 2001 to 2020. The latitudinal and altitudinal distributions of the 20-year averaged snow onset date, snow end date, and snow duration days are well represented by satellite-retrieved snow cover phenology matrixes. The validation results by using 850 ground snow stations demonstrated that satellite-retrieved snow cover phenology matrixes capture the spatial variability of the snow onset date, snow end date, and snow duration days at the 95% significance level during the overlapping period of 2001–2017. Moreover, a delayed snow onset date and an earlier snow end date (1.12 days decade−1, p < 0.05) are detected over the Northern Hemisphere during 2001–2020 based on the satellite-retrieved snow cover phenology matrixes. In addition, the attribution analysis indicated that snow end date dominates snow cover phenology changes and that an increased melting season temperature is the key driving factor of snow end date anomalies over the NH during 2001–2020. These results are helpful in understanding recent snow cover change and can contribute to climate projection studies.


2021 ◽  
pp. 1-9
Author(s):  
Feng Shi ◽  
Anmin Duan ◽  
Qiuzhen Yin ◽  
John T Bruun ◽  
Cunde Xiao ◽  
...  

Abstract The Qinghai–Tibetan Plateau and Arctic both have an important influence on global climate, but the correlation between climate variations in these two regions remains unclear. Here we reconstructed and compared the summer temperature anomalies over the past 1,120 yr (900–2019 CE) in the Qinghai–Tibetan Plateau and Arctic. The temperature correlation during the past millennium in these two regions has a distinct centennial variation caused by volcanic eruptions. Furthermore, the abrupt weak-to-strong transition in the temperature correlation during the sixteenth century could be analogous to this type of transition during the Modern Warm Period. The former was forced by volcanic eruptions, while the latter was controlled by changes in greenhouse gases. This implies that anthropogenic, as opposed to natural, forcing has acted to amplify the teleconnection between the Qinghai–Tibetan Plateau and Arctic during the Modern Warm Period.


2021 ◽  
Vol 13 (4) ◽  
pp. 655
Author(s):  
Animesh Choudhury ◽  
Avinash Chand Yadav ◽  
Stefania Bonafoni

The Himalayan region is one of the most crucial mountain systems across the globe, which has significant importance in terms of the largest depository of snow and glaciers for fresh water supply, river runoff, hydropower, rich biodiversity, climate, and many more socioeconomic developments. This region directly or indirectly affects millions of lives and their livelihoods but has been considered one of the most climatically sensitive parts of the world. This study investigates the spatiotemporal variation in maximum extent of snow cover area (SCA) and its response to temperature, precipitation, and elevation over the northwest Himalaya (NWH) during 2000–2019. The analysis uses Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra 8-day composite snow Cover product (MOD10A2), MODIS/Terra/V6 daily land surface temperature product (MOD11A1), Climate Hazards Infrared Precipitation with Station data (CHIRPS) precipitation product, and Shuttle Radar Topography Mission (SRTM) DEM product for the investigation. Modified Mann-Kendall (mMK) test and Spearman’s correlation methods were employed to examine the trends and the interrelationships between SCA and climatic parameters. Results indicate a significant increasing trend in annual mean SCA (663.88 km2/year) between 2000 and 2019. The seasonal and monthly analyses were also carried out for the study region. The Zone-wise analysis showed that the lower Himalaya (184.5 km2/year) and the middle Himalaya (232.1 km2/year) revealed significant increasing mean annual SCA trends. In contrast, the upper Himalaya showed no trend during the study period over the NWH region. Statistically significant negative correlation (−0.81) was observed between annual SCA and temperature, whereas a nonsignificant positive correlation (0.47) existed between annual SCA and precipitation in the past 20 years. It was also noticed that the SCA variability over the past 20 years has mainly been driven by temperature, whereas the influence of precipitation has been limited. A decline in average annual temperature (−0.039 °C/year) and a rise in precipitation (24.56 mm/year) was detected over the region. The results indicate that climate plays a vital role in controlling the SCA over the NWH region. The maximum and minimum snow cover frequency (SCF) was observed during the winter (74.42%) and monsoon (46.01%) season, respectively, while the average SCF was recorded to be 59.11% during the study period. Of the SCA, 54.81% had a SCF above 60% and could be considered as the perennial snow. The elevation-based analysis showed that 84% of the upper Himalaya (UH) experienced perennial snow, while the seasonal snow mostly dominated over the lower Himalaya (LH) and the middle Himalaya (MH).


1998 ◽  
Vol 164 (1) ◽  
pp. 41 ◽  
Author(s):  
Úna NÍ Chaoimh ◽  
Una NI Chaoimh

Author(s):  
Kenneth M. Hinkel ◽  
Andrew W. Ellis

The cryosphere refers to the Earth’s frozen realm. As such, it includes the 10 percent of the terrestrial surface covered by ice sheets and glaciers, an additional 14 percent characterized by permafrost and/or periglacial processes, and those regions affected by ephemeral and permanent snow cover and sea ice. Although glaciers and permafrost are confined to high latitudes or altitudes, areas seasonally affected by snow cover and sea ice occupy a large portion of Earth’s surface area and have strong spatiotemporal characteristics. Considerable scientific attention has focused on the cryosphere in the past decade. Results from 2 ×CO2 General Circulation Models (GCMs) consistently predict enhanced warming at high latitudes, especially over land (Fitzharris 1996). Since a large volume of ground and surface ice is currently within several degrees of its melting temperature, the cryospheric system is particularly vulnerable to the effects of regional warming. The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) states that there is strong evidence of Arctic air temperature warming over land by as much as 5 °C during the past century (Anisimov et al. 2001). Further, sea-ice extent and thickness has recently decreased, permafrost has generally warmed, spring snow extent over Eurasia has been reduced, and there has been a general warming trend in the Antarctic (e.g. Serreze et al. 2000). Most climate models project a sustained warming and increase in precipitation in these regions over the twenty-first century. Projected impacts include melting of ice sheets and glaciers with consequent increase in sea level, possible collapse of the Antarctic ice shelves, substantial loss of Arctic Ocean sea ice, and thawing of permafrost terrain. Such rapid responses would likely have a substantial impact on marine and terrestrial biota, with attendant disruption of indigenous human communities and infrastructure. Further, such changes can trigger positive feedback effects that influence global climate. For example, melting of organic-rich permafrost and widespread decomposition of peatlands might enhance CO2 and CH4 efflux to the atmosphere. Cryospheric researchers are therefore involved in monitoring and documenting changes in an effort to separate the natural variability from that induced or enhanced by human activity.


1960 ◽  
Vol 3 (27) ◽  
pp. 610-625
Author(s):  
G. Hattersley-Smith

AbstractGlaciological research on the ice cap to the north of Lake Hazen in northern Ellesmere Island was one of the main objectives of the Canadian I.G.Y. expedition to this area in 1957–1958. The method of nourishment of this ice cap and of Gilman Glacier, one of its southward-flowing outlets, was studied in pit and bore hole profiles above and below the equilibrium line, which was found at an elevation of about 1,200 m. Between an elevation of about 1,450 and 2,000 m. accumulation is by firn formation, while between about 1,280 and 1,450 m. interfingering of firn and superimposed ice occurs. At 1,800 m. the mean annual accumulation over the past twenty years is estimated as 12.8 g. cm.–2. On Gilman Glacier below the equilibrium line variations in density and crystal structure in an ice core to a depth of 25 m. are seen to depend on the proportion of firn to superimposed ice formed during accumulation. These variations correspond to past changes in the position of the equilibrium line. Englacial temperature measurements indicate a mean annual temperature of about –18.5° C. at an elevation of 1 ,040 m. A budget deficit for Gilman Glacier during two years of observations may be related to the increased summer melting of the last 20 years, deduced from pit studies at 1,800 m.


1995 ◽  
Vol 21 ◽  
pp. 71-76 ◽  
Author(s):  
David A. Robinson ◽  
Allan Frei ◽  
Mark C. Serreze

An analysis of snow-cover variability over Northern Hemisphere land masses reveals a continuation of the subnormal coverage that began in the late 1980s (relative to the 1972–present interval). While the 1994 snow year (September 1993–August 1994) exhibited a return to near-normal hemispheric extent, only three months during this period had above-normal coverage. Only 11 of the past 88 months (through October 1994) have been above the norm. Deficits have been most common in spring, over both the Eurasian and North American continents. This is a hemisphere-wide situation; positive correlations are identified between hemispheric and regional snow extents in spring, as well as in fall and winter. A number of significant associations are also recognized between regions during these three seasons; however, it is uncommon to see more than 50% of the variance in one region explained by another. These correlations are most common between adjacent regions, but some are found between regions on different continents. Only in spring are significant positive relationships between non-adjacent regions on the same continent observed.


1972 ◽  
Vol 29 (8) ◽  
pp. 1221-1225 ◽  
Author(s):  
J. M. Flowers ◽  
S. B. Saila

In the past, water temperature has been utilized in combination with some measure of fishing effort in the development of economic estimator or predictor equations for the yield of the lobster Homarus americanus. The hypothesis that the inshore lobster fishery in the United States has been overfished since the end of World War II to the point where increases in fishing effort since that time have had only minor effects on the yields was examined. It was shown that suitable yield prediction equations could be developed using only lagged and present temperatures as the independent variables. Comparisons were made of equations developed for the Maine fishery and sections of the Canadian fishery. Further analyses were done comparing equations developed using winter vs. summer temperatures and surface vs. bottom temperatures.


1985 ◽  
Vol 24 (1) ◽  
pp. 60-72 ◽  
Author(s):  
Linda E. Heusser ◽  
Joseph J. Morley

Using modern pollen and radiolarian distributions in sediments from the northwest Pacific and seas adjacent to Japan to interpret floral and faunal changes in core RC14-103 (44°02′N, 152°56′E), we recognize two major responses of the biota of eastern Hokkaido and the northwest Pacific to climatic changes since the last interglaciation. Relatively stable glacial environments (∼80,000–20,000 yr B.P.) were basically cold and wet (<4°C and ∼1000 mm mean annual temperature and precipitation, respectively) with boreal conijers and tundra/park-tundra on Hokkaido, and cool (<16°C) summer and cold (<1.0°C) winter surface temperatures offshore. Contrasting nonglacial environments (∼10,000–4000 yr B.P.) were warm and humid (>8°C and >1200 mm mean annual temperature and precipitation, respectively), supporting climax broadleaf deciduous forest with Quercus and Ulmus/Zelkova, with surface waters in the northwest Pacific characterized by warm (>1.5°C) winter and cold (10.4°–14.3°C) summer temperatures. Climatic evidence from RC14-103 shows a high degree of local and regional variation within the context of global climatic change. Correlative ocean and land records provide the detailed input necessary to assess local/regional responses to variations in other key elements (i.e., solar radiation, monsoonal variations) of the northeast Asian climate system.


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