scholarly journals On the Long-Term Climate Memory in the Surface Air Temperature Records over Antarctica: A Nonnegligible Factor for Trend Evaluation

2015 ◽  
Vol 28 (15) ◽  
pp. 5922-5934 ◽  
Author(s):  
Naiming Yuan ◽  
Minghu Ding ◽  
Yan Huang ◽  
Zuntao Fu ◽  
Elena Xoplaki ◽  
...  
Keyword(s):  
White Noise ◽  
Surface Air Temperature ◽  
Fluctuation Analysis ◽  
The West ◽  
Weather System ◽  
Air Temperatures ◽  
Antarctic Continent ◽  
Temperature Records ◽  
The Antarctic

Abstract In this study, observed temperature records of 12 stations from Antarctica island, coastline, and continental areas are analyzed by means of detrended fluctuation analysis (DFA). After Monte Carlo significance tests, different long-term climate memory (LTM) behaviors are found: temperatures from coastal and island stations are characterized by significant long-term climate memory whereas temperatures over the Antarctic continent behave more like white noise, except for the Byrd station, which is located in the West Antarctica. It is argued that the emergence of LTM may be dominated by the interactions between local weather system and external slow-varying systems (ocean), and therefore the different LTM behaviors between temperatures over the Byrd station and that over other continental stations can be considered as a reflection of the different climatic environments between West and East Antarctica. By calculating the trend significance with the effect of LTM taken into account, and further comparing the results with those obtained from assumptions of autoregressive (AR) process and white noise, it is found that 1) most of the Antarctic stations do not show any significant trends over the past several decades, and 2) more rigorous trend evaluation can be obtained if the effect of LTM is considered. Therefore, it is emphasized that for air temperatures over Antarctica, especially for the Antarctica coastline, island, and the west continental areas, LTM is nonnegligible for trend evaluation.

scholarly journals Climate change in the western Antarctic Peninsula since 1945: observations and possible causes

1998 ◽  
Vol 27 ◽  
pp. 571-575 ◽  
Author(s):  
J. C. King ◽  
S. A. Harangozo
Keyword(s):  
Sea Ice ◽  
Atmospheric Circulation ◽  
Antarctic Peninsula ◽  
The West ◽  
Sea Ice Extent ◽  
The North ◽  
Ultimate Cause ◽  
Temperature Records ◽  
High Level ◽  
The Antarctic

Temperature records from slations on the west roast of the Antarctic Peninsula show a very high level of interannual variability and, over the last 50 years, larger warming trends than are seen elsewhere in Antarctica. in this paper we investigate the role of atmospheric circulation variability and sea-ice extent variations in driving these changes. Owing to a lack of independent data, the reliability of Antarctic atmospheric analyses produced in the 1950s and 1960s cannot be readily established, but examination of the available data suggests that there has been an increase in the northerly component of the circulation over the Peninsula since the late 1950s. Few observations of sea-ice extent are available prior to 1973, but the limited data available indicate that the ice edge to the west of the Peninsula lay to the north of recently observed extremes during the very cold conditions prevailing in the late 1950s. The ultimate cause of the atmospheric-circulation changes remains to be determined and may lie outside the Antarctic region.

Life history strategy of Lepraria borealis at an Antarctic inland site, Coal Nunatak

2010 ◽  
Vol 42 (3) ◽  
pp. 339-346 ◽  
Author(s):  
Andreas ENGELEN ◽  
Peter CONVEY ◽  
Sieglinde OTT
Keyword(s):  
Life History ◽  
Environmental Conditions ◽  
Life History Strategy ◽  
Sequence Polymorphism ◽  
Internal Transcribed Spacer Region ◽  
The West ◽  
Distinctive Features ◽  
Dna Sequence Polymorphism ◽  
Antarctic Continent ◽  
The Antarctic

AbstractCoal Nunatak is an ice-free inland nunatak located on southern Alexander Island, adjacent to the west coast of the Antarctic Peninsula. Situated close to the Antarctic continent, it is characterized by harsh environmental conditions. Macroscopic colonization is restricted to micro-niches offering suitable conditions for a small number of lichens and mosses. The extreme environmental conditions place particular pressures on colonizers. Lepraria borealis is the dominant crustose lichen species present on Coal Nunatak, and shows distinctive features in its life history strategy, in particular expressing unusually low selectivity of the mycobiont towards potential photobionts. To assess selectivity, we measured algal DNA sequence polymorphism in a region of 480–660 bp of the nuclear internal transcribed spacer region of ribosomal DNA. We identified three different photobiont species, belonging to two different genera. We interpret this strategy as being advantageous in facilitating the colonization and community dominance of L. borealis under the isolation and extreme environmental conditions of Coal Nunatak.

scholarly journals Multi-periodic climate dynamics: spectral analysis of long-term instrumental and proxy temperature records

2013 ◽  
Vol 9 (1) ◽  
pp. 447-452 ◽  
Author(s):  
H.-J. Lüdecke ◽  
A. Hempelmann ◽  
C. O. Weiss
Keyword(s):  
Pearson Correlation ◽  
Temperature Drop ◽  
Ice Cores ◽  
Climate Dynamics ◽  
Fluctuation Analysis ◽  
Harmonic Decomposition ◽  
The Mean ◽  
Temperature Records ◽  
Instrumental Records

Abstract. The longest six instrumental temperature records of monthly means reach back maximally to 1757 AD and were recorded in Europe. All six show a V-shape, with temperature drop in the 19th and rise in the 20th century. Proxy temperature time series of Antarctic ice cores show this same characteristic shape, indicating this pattern as a global phenomenon. We used the mean of the six instrumental records for analysis by discrete Fourier transform (DFT), wavelets, and the detrended fluctuation analysis (DFA). For comparison, a stalagmite record was also analyzed by DFT. The harmonic decomposition of the abovementioned mean shows only six significant frequencies above periods over 30 yr. The Pearson correlation between the mean, smoothed by a 15-yr running average (boxcar) and the reconstruction using the six significant frequencies, yields r = 0.961. This good agreement has a > 99.9% confidence level confirmed by Monte Carlo simulations. It shows that the climate dynamics is governed at present by periodic oscillations. We find indications that observed periodicities result from intrinsic dynamics.

Long-term variability of Atlantic water temperature in the Svalbard fjords in conditions of past and recent global warming

2015 ◽  
Vol 5 (2) ◽  
pp. 134-142 ◽  
Author(s):  
Daniil I. Tislenko ◽  
Boris V. Ivanov
Keyword(s):  
Global Warming ◽  
Surface Air Temperature ◽  
Atlantic Water ◽  
The Arctic ◽  
Observation Data ◽  
Polar Regions ◽  
Arctic Amplification ◽  
The West ◽  
West Spitsbergen

Within last decades, the climate of our planet has underwent remarkable changes. The most notable are those called "Arctic amplification." is the changes comprise a decrease in the area of ​​multi-years ice in 2007 and 2012 in polar regions of the Northern hemisphere, accompanied by the temperature rise of intermediate Atlantic waters, increasing surface temperature. In this paper, an analysis of long-term variability of temperature transformed Atlantic waters (TAW) in the fjords of the West-Spitsbergen island (Isfjorden, Grnfjorden, Hornsund and Kongsfjorden) in the first period (1920–1940) and modern (1990–2009) warming in the Arctic is reported. It is shown that the instrumental observation data corresponds to the periods of rise in temperature in the layer of the TAW and surface air temperature (SAT) for the area of ​​the Svalbard.

Crustal density structure of the Antarctic continent from constrained 3-D gravity inversion

2020 ◽  
Author(s):  
Fei Ji ◽  
Qiao Zhang
Keyword(s):  
Gravity Inversion ◽  
Inversion Method ◽  
Rift System ◽  
Low Density ◽  
Density Structure ◽  
West Antarctica ◽  
The West ◽  
Antarctic Continent ◽  
Crustal Density ◽  
The Antarctic

<p>Crustal density is a fundamental physical parameter that helps to reveal its composition and structure, and is also significantly related to the tectonic evolution and geodynamics. Based on the latest Bouguer gravity anomalies and the constrains of 3-D shear velocity model and surface heat flow data, the 3-D gravity inversion method, incorporating deep weight function, has been used to obtain the refined density structure over the Antarctic continent. Our results show that the density anomalies changes from -0.25 g/cm<sup>3</sup> to 0.20 g/cm<sup>3</sup>. Due to the multi-phase extensional tectonics in Mesozoic and Cenozoic, the low density anomalies dominates in the West Antarctica, while the East Antarctica is characterized by high values of density anomalies. By comparing with the variations of effective elastic thickness, the inverted density structure correlates well with the lithospheric integrated strength. According to the mechanical strength and inverted density structure in the West Antarctic Rift System (WARS), our analysis found that except for the local area affected by the Cenozoic extension and magmatic activity, the crustal thermal structure in the WARS tends to be normal under the effect of heat dissipation. Finally, the low density anomalies features in West Antarctica extend to beneath the Transantarcitc Mountains (TAMs), however, we hypothesize that a single rift mechanism seems not be used to explain the entire TAMs range.</p>

scholarly journals Antarctic climate variability at regional and continental scales over the last 2,000 years

2017 ◽  
Author(s):  
Barbara Stenni ◽  
Mark A. J. Curran ◽  
Nerilie J. Abram ◽  
Anais Orsi ◽  
Sentia Goursaud ◽  
...  
Keyword(s):  
Working Group ◽  
Ice Core ◽  
West Antarctic Ice Sheet ◽  
West Antarctic ◽  
Temperature Reconstructions ◽  
Temperature Scaling ◽  
Antarctic Continent ◽  
Cooling Trend ◽  
The Antarctic

Abstract. Climate trends in the Antarctic region remain poorly characterised, owing to the brevity and scarcity of direct climate observations and the large magnitude of interannual to decadal-scale climate variability. Here, within the framework of the PAGES Antarctica 2k working group, we build an enlarged database of ice core water stable isotope records from Antarctica, consisting of 112 records. We produce both unweighted and weighted isotopic (δ18O) composites and temperature reconstructions since 0 CE, binned at 5 and 10-year resolution, for 7 climatically-distinct regions covering the Antarctic continent. Following earlier work of the Antarctica 2k working group, we also produce composites and reconstructions for the broader regions of East Antarctica, West Antarctica, and the whole continent. We use three methods for our temperature reconstructions: i) a temperature scaling based on the δ18O-temperature relationship output from an ECHAM5-wiso model simulation nudged to ERA-interim atmospheric reanalyses from 1979 to 2013, and adjusted for the West Antarctic Ice Sheet region to borehole temperature data; ii) a temperature scaling of the isotopic normalized anomalies to the variance of the regional reanalysis temperature and iii) a composite-plus-scaling approach used in a previous continental scale reconstruction of Antarctic temperature since 1 CE but applied to the new Antarctic ice core database. Our new reconstructions confirm a significant cooling trend from 0 to 1900 CE across all Antarctic regions where records extend back into the 1st millennium, with the exception of the Wilkes Land coast and Weddell Sea coast regions. Within this long-term cooling trend from 0–1900 CE we find that the warmest period occurs between 300 and 1000 CE, and the coldest interval from 1200 to 1900 CE. Since 1900 CE, significant warming trends are identified for the West Antarctic Ice Sheet, the Dronning Maud Land coast and the Antarctic Peninsula regions, and these trends are robust across the distribution of records that contribute to the unweighted isotopic composites and also significant in the weighted temperature reconstructions. Only for the Antarctic Peninsula is this most recent century-scale trend unusual in the context of natural variability over the last 2000-years. However, projected warming of the Antarctic continent during the 21st Century may soon see significant and unusual warming develop across other parts of the Antarctic continent. The extended Antarctica 2k ice core isotope database developed by this working group opens up many avenues for developing a deeper understanding of the response of Antarctic climate to natural and anthropogenic climate forcings. The first long-term quantification of regional climate in Antarctica presented herein is a basis for data-model comparison and assessments of past, present and future driving factors of Antarctic climate.

Aspects of modern Antarctic meteorology and climatology

2005 ◽  
Vol 32 (2) ◽  
pp. 334-345
Author(s):  
John Turner
Keyword(s):  
Southern Ocean ◽  
Southern Oscillation ◽  
Coastal Region ◽  
First Century ◽  
Near Surface ◽  
Weather Forecasts ◽  
Air Temperatures ◽  
Oceanic Climate ◽  
Antarctic Continent ◽  
The Antarctic

Great advances have been made in recent years in our understanding of the weather of the Antarctic and how the climate of the continent varies on a range of time-scales. The observations from the stations are still the most accurate meteorological measurements that we have, but satellites have been important in providing data for remote parts of the continent and the Southern Ocean. With the large amount of data that is available today weather forecasts are much more accurate than just a few years ago and can provide valuable guidance up to several days ahead over the Southern Ocean and Antarctic coastal region. However, predicting the weather for the interior of the Antarctic is still very difficult. Recent research has shown that the climate of the Antarctic is affected by tropical atmospheric and oceanic climate cycles, such as the El Niño-Southern Oscillation, but the links are complex. The picture of climate change across the Antarctic during the last 50 years is complex, with only the Antarctic Peninsula showing a significant warming. By the end of the twenty-first century near-surface air temperatures across much of the Antarctic continent are expected to increase by several degrees. A small increase in precipitation is also expected.

Spatial and temporal variation of surface air temperature at different altitude zone in recent 30 years over Nepal

MAUSAM ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 417-428
Author(s):  
JANAK LAL NAYAVA ◽  
SUNIL ADHIKARY ◽  
OM RATNA BAJRACHARYA
Keyword(s):  
Air Temperature ◽  
Surface Air Temperature ◽  
Temperature Data ◽  
Lapse Rate ◽  
Spatial And Temporal Variation ◽  
Mountain Regions ◽  
Temperature Lapse Rate ◽  
Air Temperatures ◽  
Long Term Trend

This paper investigates long term (30 yrs) altitudinal variations of surface air temperatures based on air temperature data of countrywide scattered 22 stations (15 synoptic and 7 climate stations) in Nepal. Several researchers have reported that rate of air temperature rise (long term trend of atmospheric warming) in Nepal is highest in the Himalayan region (~ 3500 m asl or higher) compared to the Hills and Terai regions. Contrary to the results of previous researchers, however this study found that the increment of annual mean temperature is much higher in the Hills (1000 to 2000 m asl) than in the Terai and Mountain Regions. The temperature lapse rate in a wide altitudinal range of Nepal (70 to 5050 m asl) is -5.65 °C km-1. Warming rates in Terai and Trans-Himalayas (Jomsom) are 0.024 and 0.029 °C/year respectively.  

An analysis of a 34-year air temperature record from Fossil Bluff (71°S, 68°W), Antarctica

1997 ◽  
Vol 9 (3) ◽  
pp. 355-363 ◽  
Author(s):  
Stephen A. Harangozo ◽  
Steven R. Colwell ◽  
John C. King
Keyword(s):  
Air Temperature ◽  
Antarctic Peninsula ◽  
Surface Air Temperature ◽  
Temperature Record ◽  
West Antarctic ◽  
Air Temperatures ◽  
Marguerite Bay ◽  
First Time ◽  
Snow Temperature

An analysis of a long-term surface air temperature record for Fossil Bluff in the George VI Sound, West Antarctic Peninsula (WAP) documents in detail some important aspects of the climate of this area for the first time. The analysis identifies the close dependency of air temperatures on latitude in the WAP but reveals that the strength of this dependency is greatest in winter. This result along with others leads to the Fossil Bluff climate regime being characterized as ‘continental’ rather than ‘maritime’ as found further north. The WAP as a whole displays large interannual temperature variability but this is greatest in Marguerite Bay rather than the Fossil Bluff area. Evidence is also provided for secular climatic change appearing in summer throughout the WAP over the last few decades. The representativeness of existing Antarctic Peninsula annual air temperature climatologies, based mainly on snow temperature measurements, for the winter and summer periods is also noted.

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