Different Climatic Effects of the Arctic and Antarctic ice Covers on Land Surface Temperature in the Northern Hemisphere: Application of Liang-Kleeman Information Flow Method and CAM4.0

2021 ◽  
Author(s):  
Shunyu Jiang ◽  
Haibo HU ◽  
William Perrie ◽  
Ning Zhang ◽  
Haokun Bai ◽  
...  
Keyword(s):  
North America ◽  
East Asia ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Information Flow ◽  
Air Temperature ◽  
The Arctic ◽  
High Latitudes ◽  
Flow Method ◽  
The Antarctic

Abstract Ice covers in high latitudes play important role in the global atmospheric circulation and abnormal temperature distribution. The observations have revealed the differences in the interannual variability of the Arctic and Antarctic ice covers, but their respective climate effect is not clear. The Liang-Kleeman information flow method is used to reveal the causal relationships from the sea ices of the Arctic and Antarctic to the global air temperature. The results point out that changes of the Arctic or Antarctic sea ices both have significant impacts on the global air temperature. Especially for the air temperature in East Asia and North America, the interannual variation of the Antarctic sea ice has an even stronger impact than the Arctic ice covers. This causality is further proved by the General Atmospheric Circulation Model (CAM4.0). In the numerical experiments, the ice covers in Arctic and Antarctic are changed individually or simultaneously as the forcing fields, and then the respective climate effects are analyzed. The results show that both the Arctic and Antarctic ice cover variations can change the intensity of atmospheric baroclinic disturbance in mid-high latitudes of individual hemisphere, generating wave energy transmission across the equator in the meridional direction, and eventually causing air temperature anomalies in both hemispheres. Furthermore, the Antarctic ice covers are closer to the mid-high latitude atmospheric jets in the southern hemisphere. Therefore, the changes of Antarctic ice covers lead to a larger atmospheric wave-activity flux response, and quickly spread to the northern hemisphere, causing more significant temperature anomalies over the East Asia and North America.

scholarly journals Continentality and Oceanity in the Mid and High Latitudes of the Northern Hemisphere and Their Links to Atmospheric Circulation

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Edvinas Stonevicius ◽  
Gintautas Stankunavicius ◽  
Egidijus Rimkus
Keyword(s):  
North America ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climatic Conditions ◽  
High Latitudes ◽  
Teleconnection Patterns ◽  
The Pacific ◽  
The Impact

The climate continentality or oceanity is one of the main characteristics of the local climatic conditions, which varies with global and regional climate change. This paper analyzes indexes of continentality and oceanity, as well as their variations in the middle and high latitudes of the Northern Hemisphere in the period 1950–2015. Climatology and changes in continentality and oceanity are examined using Conrad’s Continentality Index (CCI) and Kerner’s Oceanity Index (KOI). The impact of Northern Hemisphere teleconnection patterns on continentality/oceanity conditions was also evaluated. According to CCI, continentality is more significant in Northeast Siberia and lower along the Pacific coast of North America as well as in coastal areas in the northern part of the Atlantic Ocean. However, according to KOI, areas of high continentality do not precisely correspond with those of low oceanity, appearing to the south and west of those identified by CCI. The spatial patterns of changes in continentality thus seem to be different. According to CCI, a statistically significant increase in continentality has only been found in Northeast Siberia. In contrast, in the western part of North America and the majority of Asia, continentality has weakened. According to KOI, the climate has become increasingly continental in Northern Europe and the majority of North America and East Asia. Oceanity has increased in the Canadian Arctic Archipelago and in some parts of the Mediterranean region. Changes in continentality were primarily related to the increased temperature of the coldest month as a consequence of changes in atmospheric circulation: the positive phase of North Atlantic Oscillation (NAO) and East Atlantic (EA) patterns has dominated in winter in recent decades. Trends in oceanity may be connected with the diminishing extent of seasonal sea ice and an associated increase in sea surface temperature.

Predictable Patterns of Wintertime Surface Air Temperature in Northern Hemisphere and Their Predictability Sources in the SEAS5

2020 ◽  
Vol 33 (24) ◽  
pp. 10743-10754
Author(s):  
Hongdou Fan ◽  
Lin Wang ◽  
Yang Zhang ◽  
Youmin Tang ◽  
Wansuo Duan ◽  
...  
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Southern Oscillation ◽  
Arctic Sea Ice ◽  
Prediction Skill ◽  
The Arctic ◽  
The Tibetan Plateau ◽  
Central Pacific ◽  
The Pacific

AbstractBased on 36-yr hindcasts from the fifth-generation seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (SEAS5), the most predictable patterns of the wintertime 2-m air temperature (T2m) in the extratropical Northern Hemisphere are extracted via the maximum signal-to-noise (MSN) empirical orthogonal function (EOF) analysis, and their associated predictability sources are identified. The MSN EOF1 captures the warming trend that amplifies over the Arctic but misses the associated warm Arctic–cold continent pattern. The MSN EOF2 delineates a wavelike T2m pattern over the Pacific–North America region, which is rooted in the tropical forcing of the eastern Pacific-type El Niño–Southern Oscillation (ENSO). The MSN EOF3 shows a wavelike T2m pattern over the Pacific–North America region, which has an approximately 90° phase difference from that associated with MSN EOF2, and a loading center over midlatitude Eurasia. Its sources of predictability include the central Pacific-type ENSO and Eurasian snow cover. The MSN EOF4 reflects T2m variability surrounding the Tibetan Plateau, which is plausibly linked to the remote forcing of the Arctic sea ice. The information on the leading predictable patterns and their sources of predictability is further used to develop a calibration scheme to improve the prediction skill of T2m. The calibrated prediction skill in terms of the anomaly correlation coefficient improves significantly over midlatitude Eurasia in a leave-one-out cross-validation, implying a possible way to improve the wintertime T2m prediction in the SEAS5.

scholarly journals Unraveling the Teleconnection Mechanisms that Induce Wintertime Temperature Anomalies over the Northern Hemisphere Continents in Response to the MJO

2016 ◽  
Vol 73 (9) ◽  
pp. 3557-3571 ◽  
Author(s):  
Kyong-Hwan Seo ◽  
Hyun-Ju Lee ◽  
Dargan M. W. Frierson
Keyword(s):  
North America ◽  
Eastern Europe ◽  
Northern Hemisphere ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Temperature Variations ◽  
Temperature Anomalies ◽  
Air Temperature Variations

Abstract Significant extratropical surface air temperature variations arise as a result of teleconnections induced by the Madden–Julian oscillation (MJO). The authors elucidate the detailed physical processes responsible for the development of temperature anomalies over Northern Hemisphere continents in response to MJO-induced heating using an intraseasonal perturbation thermodynamic equation and a wave activity tracing technique. A quantitative assessment demonstrates that surface air temperature variations are due to dynamical processes associated with a meridionally propagating Rossby wave train. Over East Asia, a local Hadley circulation causes adiabatic subsidence following MJO phase 3 to be a main driver for the warming. Meanwhile, for North America and eastern Europe, horizontal temperature advection by northerlies or southerlies is the key process for warming or cooling. A ray-tracing analysis illustrates that Rossby waves with zonal wavenumbers 2 and 3 influence the surface warming over North America and a faster wavenumber 4 affects surface temperature over eastern Europe. Although recent studies demonstrate the impacts of the Arctic Oscillation, Arctic sea ice melting, and Eurasian snow cover variations on extremely cold wintertime episodes over the NH extratropics, the weather and climate there are still considerably modulated through teleconnections induced by the tropical heat forcing. In addition, the authors show that the MJO is a real source of predictability for strong warm/cold events over these continents, suggesting a higher possibility of making a skillful forecast of temperature extremes with over 1 month of lead time.

Pathways of Influence of the Northern Hemisphere Mid–high Latitudes on East Asian Climate: A Review

2021 ◽  
Author(s):  
Jianping Li ◽  
Fei Zheng ◽  
Cheng Sun ◽  
Juan Feng ◽  
Jing Wang
Keyword(s):  
East Asia ◽  
Northern Hemisphere ◽  
Synergistic Effects ◽  
East Asian ◽  
Antagonistic Effect ◽  
The Arctic ◽  
Future Research ◽  
High Latitudes ◽  
The North ◽  
East Asian Climate

<p>This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid–high latitudes on East Asian climate within the framework of a “coupled oceanic–atmospheric (land–atmospheric or seaice–atmospheric) bridge” and “chain coupled bridge”. Four major categories of pathways are concentrated upon, as follows: Pathway A—from North Atlantic to East Asia; Pathway B—from the North Pacific to East Asia; Pathway C—from the Arctic to East Asia; and Pathway D—the synergistic effects of the mid–high latitudes and tropics. In addition, definitions of the terms “combined effect”, “synergistic effect” and “antagonistic effect” of two or more factors of influence or processes and their criteria are introduced, so as to objectively investigate those effects in future research.</p>

scholarly journals Trends and regime shifts in climatic conditions and river runoff in Estonia during 1951–2015

2017 ◽  
Vol 8 (4) ◽  
pp. 963-976 ◽  
Author(s):  
Jaak Jaagus ◽  
Mait Sepp ◽  
Toomas Tamm ◽  
Arvo Järvet ◽  
Kiira Mõisja
Keyword(s):  
Time Series ◽  
Snow Cover ◽  
Atmospheric Circulation ◽  
Air Temperature ◽  
Large Scale ◽  
Regime Shifts ◽  
The Arctic ◽  
Dry Period ◽  
Snow Cover Duration ◽  
Large Scale Atmospheric Circulation

Abstract. Time series of monthly, seasonal and annual mean air temperature, precipitation, snow cover duration and specific runoff of rivers in Estonia are analysed for detecting of trends and regime shifts during 1951–2015. Trend analysis is realised using the Mann–Kendall test and regime shifts are detected with the Rodionov test (sequential t-test analysis of regime shifts). The results from Estonia are related to trends and regime shifts in time series of indices of large-scale atmospheric circulation. Annual mean air temperature has significantly increased at all 12 stations by 0.3–0.4 K decade−1. The warming trend was detected in all seasons but with the higher magnitude in spring and winter. Snow cover duration has decreased in Estonia by 3–4 days decade−1. Changes in precipitation are not clear and uniform due to their very high spatial and temporal variability. The most significant increase in precipitation was observed during the cold half-year, from November to March and also in June. A time series of specific runoff measured at 21 stations had significant seasonal changes during the study period. Winter values have increased by 0.4–0.9 L s−1 km−2 decade−1, while stronger changes are typical for western Estonia and weaker changes for eastern Estonia. At the same time, specific runoff in April and May have notably decreased indicating the shift of the runoff maximum to the earlier time, i.e. from April to March. Air temperature, precipitation, snow cover duration and specific runoff of rivers are highly correlated in winter determined by the large-scale atmospheric circulation. Correlation coefficients between the Arctic Oscillation (AO) and North Atlantic Oscillation (NAO) indices reflecting the intensity of westerlies, and the studied variables were 0.5–0.8. The main result of the analysis of regime shifts was the detection of coherent shifts for air temperature, snow cover duration and specific runoff in the late 1980s, mostly since the winter of 1988/1989, which are, in turn, synchronous with the shifts in winter circulation. For example, runoff abruptly increased in January, February and March but decreased in April. Regime shifts in annual specific runoff correspond to the alternation of wet and dry periods. A dry period started in 1964 or 1963, a wet period in 1978 and the next dry period at the beginning of the 21st century.

Fossil flower of Staphylea L. from the Miocene amber of Mexico: New evidence of the Boreotropical Flora in low-latitude North America

2017 ◽  
Vol 108 (4) ◽  
pp. 471-478 ◽  
Author(s):  
Ana L. Hernández-Damián ◽  
Sergio R. S. Cevallos-Ferriz ◽  
Alma R. Huerta-Vergara
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
Fossil Record ◽  
First Record ◽  
High Latitudes ◽  
Low Latitude ◽  
Southern Mexico ◽  
Apparent Lack ◽  
History Of ◽  
New Evidence

ABSTRACTA new flower preserved in amber in sediments of Simojovel de Allende, México, is identified as an extinct member of Staphyleaceae, a family of angiosperms consisting of only three genera (Staphylea, Turpinia and Euscaphis), which has a large and abundant fossil record and is today distributed over the Northern Hemisphere. Staphylea ochoterenae sp. nov. is the first record of a flower for this group, which is small, pedicelled, pentamer, bisexual, with sepals and petals with similar size, dorsifixed anthers and superior ovary. Furthermore, the presence of stamens with pubescent filaments allows close comparison with extant flowers of Staphylea bulmada and S. forresti, species currently growing in Asia. However, their different number of style (one vs. three) and the apparent lack of a floral disc distinguish them from S. ochoterenae. The presence of Staphyleaceae in southern Mexico ca. 23 to 15My ago is evidence of the long history of integration of vegetation in low-latitude North America, in which some lineages, such as Staphylea, could move southwards from high latitudes of the Northern Hemisphere, as part of the Boreotropical Flora. In Mexico it grew in association with tropical elements, as suggested by the fossil record of the area.

Typification of the Mediterranean endemic conifer Juniperus turbinata (Cupressaceae)

Phytotaxa ◽  
2017 ◽  
Vol 302 (2) ◽  
pp. 165 ◽  
Author(s):  
PEDRO PABLO FERRER-GALLEGO ◽  
ROBERTO NAZZARO ◽  
INMACULADA FERRANDO ◽  
EMILIO LAGUNA
Keyword(s):  
North America ◽  
East Asia ◽  
Northern Hemisphere ◽  
Canary Islands ◽  
Mediterranean Region ◽  
The Mediterranean ◽  
Semi Arid

The genus Juniperus Linnaeus (1753: 1038) (Cupressaceae Gray, nom. cons.) is a major component of arid and semi-arid tree/shrub ecosystems throughout the Northern Hemisphere (Thorne 1972, Adams 2004, 2008, 2014, Farjon 2005). The genus is monophyletic (Adams 2004, 2008, 2014, Little 2006, Mao et al. 2010), and three monophyletic sections are currently recognized: J. sect. Caryocedrus Endlicher (1847: 2), with one species in the Mediterranean; J. sect. Juniperus, with nine species in East Asia and the Mediterranean plus the circumboreal J. communis Linnaeus (1753: 1040); and J. sect. Sabina Spach (1841: 291), with 56 species distributed in southwestern North America, Asia and the Mediterranean region, with outliers in Africa and the Canary Islands.

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