Summer Circulation Patterns, Northern Smith Sound

ARCTIC ◽  
1978 ◽  
Vol 31 (2) ◽  
Author(s):  
Samuel G. Tooma
Keyword(s):  
Summer Circulation ◽  
Circulation Patterns

scholarly journals The Role of Synoptic Cyclones for the Formation of Arctic Summer Circulation Patterns as Clustered by Self-Organizing Maps

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 474 ◽  
Author(s):  
Min-Hee Lee ◽  
Joo-Hong Kim
Keyword(s):  
Arctic Ocean ◽  
Large Scale ◽  
The Arctic ◽  
Cyclone Activity ◽  
Summer Circulation ◽  
Self Organizing Maps ◽  
Weather Patterns ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Self Organizing

Contribution of extra-tropical synoptic cyclones to the formation of mean summer atmospheric circulation patterns in the Arctic domain (≥60° N) was investigated by clustering dominant Arctic circulation patterns based on daily mean sea-level pressure using self-organizing maps (SOMs). Three SOM patterns were identified; one pattern had prevalent low-pressure anomalies in the Arctic Circle (SOM1), while two exhibited opposite dipoles with primary high-pressure anomalies covering the Arctic Ocean (SOM2 and SOM3). The time series of their occurrence frequencies demonstrated the largest inter-annual variation in SOM1, a slight decreasing trend in SOM2, and the abrupt upswing after 2007 in SOM3. Analyses of synoptic cyclone activity using the cyclone track data confirmed the vital contribution of synoptic cyclones to the formation of large-scale patterns. Arctic cyclone activity was enhanced in the SOM1, which was consistent with the meridional temperature gradient increases over the land–Arctic ocean boundaries co-located with major cyclone pathways. The composite daily synoptic evolution of each SOM revealed that all three SOMs persisted for less than five days on average. These evolutionary short-term weather patterns have substantial variability at inter-annual and longer timescales. Therefore, the synoptic-scale activity is central to forming the seasonal-mean climate of the Arctic.

scholarly journals Evaluating Boreal Summer Circulation Patterns of CMIP6 Climate Models Over The Asian Region

2021 ◽  
Author(s):  
Lulei Bu ◽  
Zhiyan Zuo ◽  
Ning An
Keyword(s):  
Extreme Events ◽  
Climate Models ◽  
Model Performance ◽  
Coupled Model ◽  
Boreal Summer ◽  
Self Organizing Map ◽  
Summer Circulation ◽  
Circulation Patterns ◽  
Daily Scale ◽  
Intercomparison Project

Abstract Our confidence in future climate projection depends on the ability of climate models to simulate the current climate, and model performance in simulating atmospheric circulation affects the ability to simulate extreme events. This study uses the self-organizing map (SOM) method to evaluate the frequency, persistence, and transition characteristics of models in the Coupled Model Intercomparison Project Phase 6 (CMIP6) for different ensembles of the 500 hPa daily geopotential height (Z500) in Asia, and then ranks all ensembles according to a comprehensive ranking metric (MR). Our results show that the SOM method is a powerful tool for assessing the daily-scale circulation simulation skills in Asia, and the results are not significantly affected by different map sizes. Positive associations between the performance of ensembles for any two of frequency, persistence, and transition were found, indicating that an ensemble that performs well for one metric is good for the others. The results of the MR ranking show that the r10i1p1f1 ensemble of CanESM5 gives the best overall simulation of 500 hPa circulation in Asia, and this is also the ensemble that best simulates frequency characteristics. The MR simulation skills of the 10 best ensembles for the position of the Western North Pacific Subtropical High (WNPSH) are far better than those of the 10 worst. Such differences may lead to errors in the simulation of extreme events. This study will help future studies in the choice of ensembles with higher circulation simulation skills to improve the credibility of their conclusions.

scholarly journals Precipitation in the Czech Republic in Light of Subjective and Objective Classifications of Circulation Types

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1536
Author(s):  
Jan Řehoř ◽  
Rudolf Brázdil ◽  
Ondřej Lhotka ◽  
Miroslav Trnka ◽  
Jan Balek ◽  
...  
Keyword(s):  
Czech Republic ◽  
Central Europe ◽  
Flow Direction ◽  
Flow Strength ◽  
Summer Circulation ◽  
The Czech Republic ◽  
Circulation Types ◽  
Circulation Patterns ◽  
Objective Classification

Many studies in Europe have investigated the relationship between climatological variables and circulation patterns expressed by various classifications of circulation types. This study provides new insights based on an analysis of precipitation in the western (Bohemia—BOH) and eastern (Moravia and Silesia—M&S) parts of the Czech Republic with respect to the subjective classification of the Czech Hydrometeorological Institute and objective classification based on the flow strength, flow direction, and vorticity during the 1961–2020 period. Circulation types are investigated in regard to their contributions to the total precipitation, mean daily precipitation totals, and precipitation probability (daily totals ≥ 1.0 mm). Types with a westerly airflow and a trough over Central Europe exhibit the highest proportions in precipitation totals. Types with a cyclone over Central Europe, especially combined with a northwestern (BOH) or northeastern (M&S) airflow, result in the highest daily mean totals and precipitation probability. Types with a southwestern airflow transport more precipitation to BOH, while those with a northeastern airflow transport more precipitation to M&S, with a slight seasonal shift in the gradient axis between winter and summer. Circulation types under both classifications are examined from the perspective of their precipitation representation in BOH and M&S and the differences between these two regions. In addition, the suitability of both classifications for precipitation analysis is investigated.

scholarly journals The Role of Synoptic Cyclones for the Formation of Arctic Summer Circulation Patterns as Clustered by Self-Organizing Maps

2019 ◽  
Author(s):  
Min-Hee Lee ◽  
Joo-Hong Kim
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Summer Circulation ◽  
Self Organizing Maps ◽  
Sea Level Pressure ◽  
Weather Patterns ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Mean Climate ◽  
Self Organizing

The contribution of extra-tropical synoptic cyclones to the formation of summer-mean atmospheric circulation patterns in the Arctic is investigated by clustering the dominant Arctic circulation patterns by the self-organizing maps (SOMs) using the daily mean sea level pressure (MSLP) in the Arctic domain (≥ 60°N). Three SOM patterns are identified: one with prevalent low pressure anomalies in the Arctic Circle (SOM1) and two opposite dipoles with primary high pressure anomalies covering the Arctic Ocean (SOM2 and SOM3). The time series of summertime occurrence frequencies demonstrate the largest inter-annual variation in the SOM1, the slight decreasing trend in the SOM2, and the abrupt upswing after 2007 in the SOM3. The relevant analyses with produced cyclone track data confirm that the vital contribution. The Arctic cyclone activity is enhanced in the SOM1 because the meridional temperature gradient increases over the land–Arctic Ocean boundaries co-located with major extra-tropical cyclone pathways. The composite daily synoptic evolutions for each SOM reveal that the persistence of all the three SOMs is less than 5 days on average. These evolutionary short-term weather patterns have substantial variability at inter-annual and longer timescales. Therefore, the synoptic-scale activity is central to forming the seasonal-mean climate of the Arctic.

The Control of Pollution from River Discharges in the Mediterranean

1986 ◽  
Vol 18 (9) ◽  
pp. 229-242 ◽  
Author(s):  
Khalil H. Mancy
Keyword(s):  
River Basin ◽  
Nile Delta ◽  
River Basin Management ◽  
Management Plan ◽  
Control Measures ◽  
European Continent ◽  
Marine Management ◽  
Circulation Patterns ◽  
Management Schemes ◽  
The Mediterranean

The pollution burden of river discharges in the Mediterranean far exceeds all other sources, e.g. land based sources. The main contributors are the Rhone, Po and Ebro. Contributions from the River Nile are expected to be much less than those from rivers in the European continent. Recent Nile management schemes and irrigation projects in Egypt are posing direct impacts on the Mediterranean. This includes the erosion of the Nile Delta and off-shore pollution due to wastewater discharges. In view of the prevailing circulation patterns in the Mediterranean, these impacts are dominant in the South Levantin region. Cutrent practices of river management do not necessarily include the protection of marine resources. Similarly, sea protection programs do not include pollution from sources in the river basin. Marine management programs are largely concerned with pollution loads at the points of river discharge. In the case of a land-locked sea, such as the Mediterranean, it is particularly important to integrate river basin management schemes in the sea protection program. Under a suitable management plan, it could be possible to determine main sources of sea pollution within the river basin. This should serve as the basis for the implementation of control measures, since the problem is not exclusively within the river basin.

Coliform transport in a pristine reservoir: modeling and field studies

1998 ◽  
Vol 37 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Elisa Garvey ◽  
John E. Tobiason ◽  
Michael Hayes ◽  
Evelyn Wolfram ◽  
David A. Reckhow ◽  
...  
Keyword(s):  
Model Development ◽  
Fate And Transport ◽  
Field Studies ◽  
Meteorological Conditions ◽  
Reservoir Modeling ◽  
Vertical Circulation ◽  
Quality Model ◽  
Circulation Patterns ◽  
In Situ Experiments

This paper reports on field studies and model development aimed at understanding coliform fate and transport in the Quabbin Reservoir, an oligotrophic drinking water supply reservoir. An investigation of reservoir currents suggested the importance of wind driven phenomena, and that both lateral and vertical circulation patterns exist. In-situ experiments of coliform decay suggested dependence on light intensity and yielded an appropriate decay coefficient to be used in CE-QUAL-W2, a two-dimensional hydrodynamic and water quality model. Modeling confirmed the sensitivity of reservoir outlet concentration to vertical variability within the reservoir, meteorological conditions, and location of coliform source.

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