scholarly journals Moisture sources and synoptic conditions of summer precipitation in the glacial zone of the East Sayan Range

2020 ◽  
Vol 17 ◽  
pp. 1-8
Author(s):  
Eduard Y. Osipov ◽  
Olga P. Osipova
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Summer Precipitation ◽  
Reanalysis Data ◽  
High Mountain ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Precipitation Record ◽  
Macro Scale ◽  
Synoptic Conditions

Abstract. Precipitation in high-mountain regions is characterized by a strong heterogeneity due to complex interaction between atmospheric circulation and steep topography, however, extremely rare network of high elevation stations hampers the adequate high resolution regional climate modeling. In this study we present new data of precipitation directly measured in high-mountain catchment, on the continental glacier (East Sayan Range, south of East Siberia) during the summer periods of 2015–2017 using automatic weather station. The precipitation record was compared with near located weather stations and ERA Interim and NCEP/NCAR reanalysis data. Precipitation mode similar to the glacier site was found at the stations located west and northwest, while ERA Interim and NCEP/NCAR reanalysis data underestimated the precipitation by 40 % and 70 %, respectively. Atmospheric circulation patterns in days with precipitation were analyzed by using mean sea level pressure, geopotential height at 700 and 500 hPa and classification of macro scale atmospheric processes of the Northern Hemisphere by Dzerdzeevskii. Summer precipitation was mostly associated with meridional southern group of large scale circulation the Northern Hemisphere, while at synoptic scale it basically fell in cyclonic (49 % of precipitation) and low-gradient cyclonic (30 %) baric fields. Six typical atmospheric circulation patterns over the East Sayan were identified for days with precipitation. The sources and atmospheric moisture transfer to the glacier was defined by using the HYSPLIT trajectory model. The most of summer precipitation (70 %) was related with western cyclones, while about 25 % of rainfalls (mainly of moderate to strong intensity) was originated from the south-east (Pacific monsoon influence).

scholarly journals Storylines of the 2018 Northern Hemisphere heat wave at pre-industrial and higher global warming levels

2020 ◽  
Author(s):  
Kathrin Wehrli ◽  
Mathias Hauser ◽  
Sonia I. Seneviratne
Keyword(s):  
Global Warming ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
System Model ◽  
Boreal Summer ◽  
Extreme Temperatures ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Anomalous Atmospheric Circulation ◽  
Maximum Temperatures

Abstract. Extreme temperatures were experienced over a large part of the Northern Hemisphere during the 2018 boreal summer (hereafter referred to as NH2018 event), leading to major impacts to agriculture and society in the affected countries. Previous studies highlighted both the anomalous atmospheric circulation patterns during the event and the background warming due to human greenhouse gas emissions as main drivers for the event. In this study, we present Earth System Model experiments investigating different storylines of the NH2018 event given the same atmospheric circulation and alternative background global warming for: no human imprint, the 2018 conditions, and different mean global warming levels (1.5 °C, 2 °C, 3 °C, and 4 °C). The results reveal that the human-induced background warming was a strong contributor to the intensity of the NH2018 event, and that resulting extremes under similar atmospheric circulation conditions at higher levels of global warming would reach very dangerous levels. About 32 % (61 %) of the inhabited or agricultural area in the investigated region would reach maximum temperatures over 40 °C under 2 °C (4 °C) of global warming and similar atmospheric circulation conditions.

Impact of Rossby waves on Norther-Hemisphere continental climate

2020 ◽  
Author(s):  
Rune Grand Graversen
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Energy Transport ◽  
Rossby Waves ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Weather And Climate ◽  
Static Energy ◽  
Arctic Temperature ◽  
Continental Climate

<p>Mid-latitude continental weather and climate are strongly affected by the atmospheric circulation patterns such as Rossby waves and cyclones. For instance these patterns may lead to warm- and humid-air advection over western part of the continents in winter and cold-air advection in these regions during summer. By applying a newly developed method for splitting the atmospheric latent and dry-static energy transport into waves, hereby decomposing the energy transport into parts accomplished by e.g. Rossby waves and synoptic-scale weather systems, the effect of different atmospheric circulation patterns on Northern-Hemisphere continental climate is investigated.</p><p>Climate change and the associated Arctic temperature amplification may impact mid-latitude atmospheric circulation. Here we investigate the effect on Northern-Hemisphere continental climate from changes over recent decades in the atmospheric circulation patterns using the above-mentioned method.</p>

scholarly journals Storylines of the 2018 Northern Hemisphere heatwave at pre-industrial and higher global warming levels

2020 ◽  
Vol 11 (4) ◽  
pp. 855-873
Author(s):  
Kathrin Wehrli ◽  
Mathias Hauser ◽  
Sonia I. Seneviratne
Keyword(s):  
Global Warming ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
System Model ◽  
Boreal Summer ◽  
Daily Maximum ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Anomalous Atmospheric Circulation ◽  
Maximum Temperatures

Abstract. Extreme temperatures were experienced over a large part of the Northern Hemisphere during the 2018 boreal summer (hereafter referred to as “NH2018 event”), leading to major impacts on agriculture and society in the affected countries. Previous studies highlighted both the anomalous atmospheric circulation patterns during the event and the background warming due to human greenhouse gas emissions as main drivers of the event. In this study, we present Earth system model experiments investigating different storylines of the NH2018 event given the same atmospheric circulation and alternative background global warming for no human imprint, the 2018 conditions, and different mean global warming levels 1.5, 2, 3 and 4 ∘C. The results reveal that the human-induced background warming was a strong contributor to the intensity of the NH2018 event, and that resulting extremes under similar atmospheric circulation conditions at higher levels of global warming would reach dangerous levels. Compared to 9 % during the NH2018 event, about 13 % (34 %) of the inhabited or agricultural area in the investigated region would reach daily maximum temperatures over 40 ∘C under 2 ∘C (4 ∘C) of global warming and similar atmospheric circulation conditions.

scholarly journals Spatio-temporal variability of precipitation over the Western Balkan countries and its links with the atmospheric circulation patterns

2021 ◽  
Vol 71 (1) ◽  
pp. 29-42
Author(s):  
Dragan Milosevic ◽  
Rastislav Stojsavljevic ◽  
Szilárd Szabó ◽  
Ugljesa Stankov ◽  
Stevan Savic ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Bosnia And Herzegovina ◽  
Summer Precipitation ◽  
The Arctic ◽  
Annual Precipitation ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Precipitation Decrease ◽  
Precipitation Increase ◽  
Mediterranean Oscillation

Temporal and spatial variability of annual and seasonal precipitation from 71 stations located in Western Balkan (WB) countries (Serbia, Bosnia and Herzegovina, and Montenegro) and their correlations with nine atmospheric circulation patterns was examined for the period 1950-2016. Annual precipitation increased significantly throughout the WB (from 2% to 8% per decade) on 20% of stations located mainly in the mountainous western Serbia and eastern Bosnia and Herzegovina. Winter was characterized by non?significant precipitation changes in most of the studied area, with only a few stations characterized by significant precipitation increase (up to 12% per decade) in the mountainous area of WB, and a few stations characterized by significant decrease (up to -6% per decade) in the Pannonian plain. Significant precipitation increase was noticed on 15% of the stations in spring, while it was noticed on 17% of the stations in autumn. Summer precipitation decreased significantly (up to -5% per decade) on a limited area of northern Serbia (6% of the stations), while the majority of stations showed non?significant increase. The strongest influences on annual precipitation in WB region are of the Arctic Oscillation (AO) and Mediterranean Oscillation (MO), leading to the precipitation decrease during their positive phases. Winter precipitation is significantly negatively correlated with AO, East Atlantic/Western Russia oscillation (EA/WR), and North Atlantic Oscillation (NAO) and has a significant positive correlation with Western Mediterranean Oscillation (WeMO) on the majority of stations. MO has the strongest influence on summer precipitation in WB region leading to precipitation decrease, while AO has the dominant influence on precipitation in the region during autumn.

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