scholarly journals Dominant Modes of Wintertime Upper-Tropospheric Temperature Variations over Asia and Links to Surface Climate

2013 ◽  
Vol 26 (22) ◽  
pp. 9043-9060 ◽  
Author(s):  
Xingwen Jiang ◽  
Song Yang ◽  
Yueqing Li ◽  
Zongjian Ke ◽  
Jianping Li ◽  
...  
Keyword(s):  
Southern Oscillation ◽  
Southern China ◽  
The Arctic ◽  
The Sea Of Japan ◽  
Tropospheric Temperature ◽  
The Third ◽  
Surface Climate ◽  
Negative Center ◽  
Second Mode ◽  
Positive Center

Abstract In this study, the authors investigate the variations and predictability of wintertime upper-tropospheric temperature (UTT) over Asia, which are often linked to severe climate anomalies, and the associated features of large-scale circulation and surface climate. The ECMWF Interim Re-Analysis (ERA-Interim) and hindcast of the NCEP Climate Forecast System, version 2 (CFSv2), are mainly analyzed. The first empirical orthogonal function mode of UTT shows a dipole structure, with a strong positive center over southern China and a weak negative center over Mongolia. The second mode is featured by a monopole variation, with a positive center appearing from the northwestern Tibetan Plateau (TP) to Japan. The third mode exhibits a tripole pattern, with two positive centers over Pakistan and the Sea of Japan and a negative center over central Asia. The first mode is linked to El Niño–Southern Oscillation, accompanied by surface warming over the southeastern TP and deficient precipitation over southern China, the Korean Peninsula, and from equatorial East Africa to the east of the TP. The second mode is associated with circulation anomalies similar to those associated with the Arctic Oscillation, with significant warming over East Asia. The third mode features two wave trains and is linked to the Middle East jet stream, and is associated with excessive precipitation from the eastern TP to southern Japan. The CFSv2 can predict the first mode skillfully by several months in advance, but it shows little skill in predicting the second and third modes.

scholarly journals Interannual Variability and Trends in Sea Surface Temperature, Lower and Middle Atmosphere Temperature at Different Latitudes for 1980–2019

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 454
Author(s):  
Andrew R. Jakovlev ◽  
Sergei P. Smyshlyaev ◽  
Vener Y. Galin
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Lower Stratosphere ◽  
Middle Atmosphere ◽  
Southern Oscillation ◽  
Lower Troposphere ◽  
Reanalysis Data ◽  
Sea Surface ◽  
The Arctic ◽  
The Impact

The influence of sea-surface temperature (SST) on the lower troposphere and lower stratosphere temperature in the tropical, middle, and polar latitudes is studied for 1980–2019 based on the MERRA2, ERA5, and Met Office reanalysis data, and numerical modeling with a chemistry-climate model (CCM) of the lower and middle atmosphere. The variability of SST is analyzed according to Met Office and ERA5 data, while the variability of atmospheric temperature is investigated according to MERRA2 and ERA5 data. Analysis of sea surface temperature trends based on reanalysis data revealed that a significant positive SST trend of about 0.1 degrees per decade is observed over the globe. In the middle latitudes of the Northern Hemisphere, the trend (about 0.2 degrees per decade) is 2 times higher than the global average, and 5 times higher than in the Southern Hemisphere (about 0.04 degrees per decade). At polar latitudes, opposite SST trends are observed in the Arctic (positive) and Antarctic (negative). The impact of the El Niño Southern Oscillation phenomenon on the temperature of the lower and middle atmosphere in the middle and polar latitudes of the Northern and Southern Hemispheres is discussed. To assess the relative influence of SST, CO2, and other greenhouse gases’ variability on the temperature of the lower troposphere and lower stratosphere, numerical calculations with a CCM were performed for several scenarios of accounting for the SST and carbon dioxide variability. The results of numerical experiments with a CCM demonstrated that the influence of SST prevails in the troposphere, while for the stratosphere, an increase in the CO2 content plays the most important role.

scholarly journals Effects of Climatic Drivers and Teleconnections on Late 20th Century Trends in Spring Freshet of Four Major Arctic-Draining Rivers

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 179
Author(s):  
Roxanne Ahmed ◽  
Terry Prowse ◽  
Yonas Dibike ◽  
Barrie Bonsal
Keyword(s):  
Arctic Ocean ◽  
Large Scale ◽  
Southern Oscillation ◽  
Rate Of Change ◽  
The Arctic ◽  
Late 20Th Century ◽  
Basin Scale ◽  
The Arctic Ocean ◽  
Spring Freshet ◽  
Climatic Drivers

Spring freshet is the dominant annual discharge event in all major Arctic draining rivers with large contributions to freshwater inflow to the Arctic Ocean. Research has shown that the total freshwater influx to the Arctic Ocean has been increasing, while at the same time, the rate of change in the Arctic climate is significantly higher than in other parts of the globe. This study assesses the large-scale atmospheric and surface climatic conditions affecting the magnitude, timing and regional variability of the spring freshets by analyzing historic daily discharges from sub-basins within the four largest Arctic-draining watersheds (Mackenzie, Ob, Lena and Yenisei). Results reveal that climatic variations closely match the observed regional trends of increasing cold-season flows and earlier freshets. Flow regulation appears to suppress the effects of climatic drivers on freshet volume but does not have a significant impact on peak freshet magnitude or timing measures. Spring freshet characteristics are also influenced by El Niño-Southern Oscillation, the Pacific Decadal Oscillation, the Arctic Oscillation and the North Atlantic Oscillation, particularly in their positive phases. The majority of significant relationships are found in unregulated stations. This study provides a key insight into the climatic drivers of observed trends in freshet characteristics, whilst clarifying the effects of regulation versus climate at the sub-basin scale.

The present and future competence of the European Union in the Arctic

Polar Record ◽  
2011 ◽  
Vol 48 (4) ◽  
pp. 361-371 ◽  
Author(s):  
Timo Koivurova ◽  
Kai Kokko ◽  
Sebastien Duyck ◽  
Nikolas Sellheim ◽  
Adam Stepien
Keyword(s):  
International Negotiations ◽  
The Arctic ◽  
The European Union ◽  
Crucial Importance ◽  
Arctic Council ◽  
The Third ◽  
Broad Array ◽  
The Subject ◽  
Arctic Policy ◽  
The Eu

ABSTRACTThe European Union's (EU's) intention of becoming a permanent observer in the Arctic Council and the reluctance of Arctic actors to grant it that status have made the union's aspirations in the Arctic the subject of a continuing debate. The discussion appears to be dominated by geographical considerations and the EU's gradually emerging Arctic policy. This article puts forward a different view of the EU's presence in the region, one drawing on an analysis of relevant EU competences. As a complex international actor, the EU has acquired a broad array of decision-making powers from its member states, powers that partly extend to Iceland and Norway via the EEA Agreement. Moreover, the EU has in many cases become a relevant actor in international negotiations and treaty making processes the outcomes of which are of crucial importance for the governance of the Arctic. Our argument in the third and concluding section is that only by including the EU in Arctic governance can the international community provide better prospects for the union to sensitise its policies and discourses to the Arctic realities and for other Arctic actors to understand how the union functions. This argument is supported by an analysis of the EU's restrictions on the import of seal products and the ensuing litigation.

Potential predictability of Southwest US rainfall : role of tropical and high-latitude variability

2021 ◽  
pp. 1-45
Keyword(s):  
Time Scale ◽  
Climate Model ◽  
Southern Oscillation ◽  
Seasonal Prediction ◽  
Seasonal Rainfall ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Potential Predictability ◽  
Subseasonal Variability ◽  
The Tropics

Abstract This study explores the potential predictability of Southwest US (SWUS) precipitation for the November-March season in a set of numerical experiments performed with the Whole Atmospheric Community Climate Model. In addition to the prescription of observed sea surface temperature and sea ice concentration, observed variability from the MERRA-2 reanalysis is prescribed in the tropics and/or the Arctic through nudging of wind and temperature. These experiments reveal how a perfect prediction of tropical and/or Arctic variability in the model would impact the prediction of seasonal rainfall over the SWUS, at various time scales. Imposing tropical variability improves the representation of the observed North Pacific atmospheric circulation, and the associated SWUS seasonal precipitation. This is also the case at the subseasonal time scale due to the inclusion of the Madden-Julian Oscillation (MJO) in the model. When additional nudging is applied in the Arctic, the model skill improves even further, suggesting that improving seasonal predictions in high latitudes may also benefit prediction of SWUS precipitation. An interesting finding of our study is that subseasonal variability represents a source of noise (i.e., limited predictability) for the seasonal time scale. This is because when prescribed in the model, subseasonal variability, mostly the MJO, weakens the El Niño Southern Oscillation (ENSO) teleconnection with SWUS precipitation. Such knowledge may benefit S2S and seasonal prediction as it shows that depending on the amount of subseasonal activity in the tropics on a given year, better skill may be achieved in predicting subseasonal rather than seasonal rainfall anomalies, and conversely.

Comparative Analysis of Nutritional Quality of Dendrobium Officinale Kimura Et Migo After Transplantation of Artificially Cultivated Plants From South to North China During Different Growing Years

2021 ◽  
Author(s):  
Xiaohui Guo ◽  
Shijing Zhang ◽  
Ting Yan ◽  
Guoqiang Yuan ◽  
Yafeng Dai ◽  
...  
Keyword(s):  
Nutritional Quality ◽  
Southern China ◽  
Northern China ◽  
Habitat Destruction ◽  
Dendrobium Officinale ◽  
Cultivated Plants ◽  
Total Phenolic ◽  
The Third ◽  
Nutritional Compounds ◽  
Nutrient Profiles

Abstract Background: Dendrobium officinale Kimura et Migo is a traditional functional food and medicinal plant in China. Due to low natural regeneration rates, habitat destruction, excessive collection and commercial trade, D. officinale is severely threatened, and commercial artificial-sheltered cultivation has been massively used to meet the needs of the market. Aim: To comprehensively compare the accumulation of nutritional compounds during 3-5 years of introduced, artificial-sheltered cultivation from southern to northern China.Methods: D. officinale of the same species were artificially cultivated in the southern traditional cultivation area, Anhui and the new northern cultivation area, Beijing. First, samples were collected in the third, fourth, and fifth years of growth, and nutritional quality indexes, including polysaccharides, alkaloids, flavonoids and total phenolic content, were determined. Second, an untargeted metabolomics method was used to investigate metabolic variations in D. officinale stems between Anhui and Beijing cultures in the fifth year.Results: After comparing the nutrient accumulation in different growing years, the idea harvest time was found in the third growing year in both cultivation areas. Of them, the contents of polysaccharides, flavonoids and total polyphenol were higher in cultivation in Anhui than Beijing, but the accumulation of alkaloid content was much lower in Anhui. The highest amount of polysaccharides of Dendrobium officinale was found in the three-year cultivation in Anhui, which reached 515.75 mg/g. When metabolites were analysed, a total of 272 metabolites were detected in the current study, including 27 up-regulated and 73 down-regulated metabolites in D. officinale cultivated in Beijing compared with samples from Anhui. Conclusion: D. officinale artificially and transplanted cultivated from southern to northern China showed some significant differences in the accumulation of nutrient compounds. Planting in northern China has some specific advantages, but the overall nutritional value is not as good as planting in southern China. Our study contributes to a better understanding of the nutrient profiles of D. officinale through artificial cultivation in different areas.

scholarly journals Influence of Arctic Stratospheric Ozone on Surface Climate in CCMI models

2018 ◽  
Author(s):  
Ohad Harari ◽  
Chaim I. Garfinkel ◽  
Olaf Morgenstern ◽  
Guang Zeng ◽  
Simone Tilmes ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Climate Model ◽  
Southern Oscillation ◽  
Stratospheric Ozone ◽  
Internal Variability ◽  
Tropical Circulation ◽  
Polar Cap ◽  
Sea Level Pressure ◽  
Surface Climate ◽  
Stratospheric Variability

Abstract. The Northern Hemisphere and tropical circulation response to interannual variability in Arctic stratospheric ozone is analyzed in a set of the latest model simulations archived for the Chemistry-Climate Model Initiative (CCMI) project. All models simulate a connection between ozone variability and temperature/geopotential height in the lower stratosphere similar to that observed. A connection between Arctic ozone variability and polar cap sea-level pressure is also found, but additional analysis suggests that it is mediated by the dynamical variability that typically drives the anomalous ozone concentrations. The CCMI models also show a connection between Arctic stratospheric ozone and the El Nino Southern Oscillation (ENSO): the CCMI models show a tendency of Arctic stratospheric ozone variability to lead ENSO variability one to two years later. While this effect is much weaker than that observed, it is still statistically significant. Overall, Arctic stratospheric ozone is related to lower stratospheric variability and may also influence the surface in both polar and tropical latitudes, though these impacts can be masked by internal variability if data is only available for ~ 40 years.

scholarly journals The Interannual Variability of the Haines Index over North America

2013 ◽  
Vol 52 (11) ◽  
pp. 2396-2409 ◽  
Author(s):  
Lejiang Yu ◽  
Shiyuan Zhong ◽  
Xindi Bian ◽  
Warren E. Heilman ◽  
Joseph J. Charney
Keyword(s):  
United States ◽  
Pacific Ocean ◽  
North America ◽  
Interannual Variability ◽  
Large Scale ◽  
Southern Oscillation ◽  
Southeastern United States ◽  
Lower Atmosphere ◽  
The Arctic ◽  
Fire Weather Index

AbstractThe Haines index (HI) is a fire-weather index that is widely used as an indicator of the potential for dry, low-static-stability air in the lower atmosphere to contribute to erratic fire behavior or large fire growth. This study examines the interannual variability of HI over North America and its relationship to indicators of large-scale circulation anomalies. The results show that the first three HI empirical orthogonal function modes are related respectively to El Niño–Southern Oscillation (ENSO), the Arctic Oscillation (AO), and the interdecadal sea surface temperature variation over the tropical Pacific Ocean. During the negative ENSO phase, an anomalous ridge (trough) is evident over the western (eastern) United States, with warm/dry weather and more days with high HI values in the western and southeastern United States. During the negative phase of the AO, an anomalous trough is found over the western United States, with wet/cool weather and fewer days with high HI, while an anomalous ridge occurs over the southern United States–northern Mexico, with an increase in the number of days with high HI. After the early 1990s, the subtropical high over the eastern Pacific Ocean and the Bermuda high were strengthened by a wave train that was excited over the tropical western Pacific Ocean and resulted in warm/dry conditions over the southwestern United States and western Mexico and wet weather in the southeastern United States. The above conditions are reversed during the positive phase of ENSO and AO and before the early 1990s.

scholarly journals Halogenated Greenhouse Gases Made Global Warming Primarily

2022 ◽  
Author(s):  
Qing-Bin Lu
Keyword(s):  
Sea Ice ◽  
Greenhouse Gases ◽  
Land Surface ◽  
Southern Oscillation ◽  
Theoretical Calculations ◽  
Global Climate ◽  
Surface Air Temperature ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Snow Cover Extent

Abstract Time-series observations of global lower stratospheric temperature (GLST), global land surface air temperature (LSAT), global mean surface temperature (GMST), sea ice extent (SIE) and snow cover extent (SCE), together with observations reported in Paper I, combined with theoretical calculations of GLSTs and GMSTs, have provided strong evidence that ozone depletion and global climate changes are dominantly caused by human-made halogen-containing ozone-depleting substances (ODSs) and greenhouse gases (GHGs) respectively. Both GLST and SCE have become constant since the mid-1990s and GMST/LSAT has reached a peak since the mid-2000s, while regional continued warmings at the Arctic coasts (particularly Russia and Alaska) in winter and spring and at some areas of Antarctica are observed and can be well explained by a sea-ice-loss warming amplification mechanism. The calculated GMSTs by the parameter-free warming theory of halogenated GHGs show an excellent agreement with the observed GMSTs after the natural El Niño southern oscillation (ENSO) and volcanic effects are removed. These results provide a convincing mechanism of global climate change and will make profound changes in our understanding of atmospheric processes. This study also emphasizes the critical importance of continued international efforts in phasing out all anthropogenic halogenated ODSs and GHGs.

scholarly journals Tropospheric temperature variation over India and links with the Indian summer monsoon : 1971-2000

MAUSAM ◽  
2022 ◽  
Vol 53 (3) ◽  
pp. 289-308
Author(s):  
D. R. KOTHAWALE ◽  
K. RUPA KUMAR
Keyword(s):  
Summer Monsoon ◽  
Southern Oscillation ◽  
Monsoon Season ◽  
Temporal Variations ◽  
Mean Annual Temperature ◽  
Tropospheric Temperature ◽  
Temperature Variations ◽  
Annual Cycles ◽  
The Mean ◽  
Spatio Temporal

In the context of the ever increasing interest in the regional aspects of global warming, understanding the spatio-temporal variations of tropospheric temperature over India is of great importance. The present study, based on the data from 19 well distributed radiosonde stations for the period 1971-2000, examines the seasonal and annual mean temperature variations at the surface and five selected upper levels, viz., 850, 700, 500, 200 and 150 hPa. An attempt has also been made to bring out the association between tropospheric temperature variations over India and the summer monsoon variability, including the role of its major teleconnection parameter, the El Niño/Southern Oscillation (ENSO).   Seasonal and annual mean all-India temperature series are analyzed for surface and five tropospheric levels.  The mean annual cycles of temperature at different tropospheric levels indicate that the pre-monsoon season is slightly warmer than the monsoon season at the surface, 850 hPa and 150 hPa levels, while it is relatively cooler at all intermediate levels.  The mean annual temperature shows a warming of 0.18° C and 0.3° C per 10 years at the surface and 850 hPa, respectively.   Tropospheric temperature anomaly composites of excess (deficient) monsoon rainfall years show pronounced positive (negative) anomalies during the month of May, at all the levels.  The pre-monsoon pressure of Darwin has significant positive correlation with the monsoon temperature at the surface and 850 hPa.

scholarly journals Arktisk råds rolle i polarpolitikken

Nordlit ◽  
2012 ◽  
Vol 16 (1) ◽  
pp. 205 ◽  
Author(s):  
Torbjørn Pedersen
Keyword(s):  
United States ◽  
Arctic Ocean ◽  
The United States ◽  
The Arctic ◽  
Arctic Council ◽  
The Third ◽  
The Arctic Ocean ◽  
Foreign Policies

This article discusses what role(s) member governments want the Arctic Council to have in Arctic affairs. It compares the foreign policies of the five littoral states of the Arctic Ocean: Canada, Denmark, Norway, Russia, and the United States. It identifies and examines three determining debates on a ministerial level over the Arctic Council and the issues it might address: The first debate preceded the Arctic Council's creation in 1996; the second thrived as the five Arctic littoral states convened in Ilulissat, Greenland in 2008; and the third followed a political shift inthe United States in 2009.

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