Surface wind and vertical extent features of the explosive cyclones in the Northern Hemisphere based on the ERA‐I reanalysis data

2021 ◽  
Author(s):  
Li‐Zhi Jiang ◽  
Shen‐Ming Fu ◽  
Jian‐Hua Sun ◽  
Rui Fu ◽  
Wan‐Li Li ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Surface Wind ◽  
Reanalysis Data ◽  
Vertical Extent ◽  
Explosive Cyclones

Vertical extent related characteristics of the explosive cyclones in the Northern Hemisphere: A 40-yr climatology study based on the ERA-I reanalysis

2020 ◽  
Author(s):  
Shenming Fu ◽  
Lizhi Jiang ◽  
Jianhua Sun
Keyword(s):  
Northern Hemisphere ◽  
Three Dimensional ◽  
Reanalysis Data ◽  
Dimensional System ◽  
Weather System ◽  
New Findings ◽  
Explosive Cyclones ◽  
Northern Atlantic ◽  
Northern Pacific ◽  
Three Dimensional System

<p>The explosive cyclone (EC), which is the most destructive subcategory of the extratropical cyclone, has been a research center for decades. Many key features of this type of cyclone have been shown, however, as a three-dimensional system, their vertical extents and associated important characteristics still remain vague. This study attempts to fill this vacancy by focusing on ECs’ vertical extents related features in the Northern Hemisphere on the basis of the ERA-I reanalysis data during a 40-yr period. Some new findings are reached: (i) overall, the EC is a type of deep weather system, as more than 63% of them reach an upmost level above 300 hPa, whereas only less than 12% of them maintain below 500 hPa during their whole life spans. (ii) ECs’ vertical extents show remarkable latitude dependent features (maximum vertical extents appear in the zone of 55oN-65oN), and they also show obvious seasonal changes, with the minimum vertical extents appeared in January. (iii) ECs’ maximum vertical extents show a significant positive correlation with their minimum central pressure, whereas, their maximum vertical extents show no obvious relationship to the ECs’ maximum deepening rates and maximum 10-m winds. (iv) in general, ECs over the northern Pacific Ocean have larger intensity, longer life spans, and thicker vertical extents than those of the ECs over the northern Atlantic Ocean.</p>

scholarly journals The concurrence of Atmospheric Rivers and explosive cyclogenesis in the North Atlantic and North Pacific basins

2017 ◽  
Author(s):  
Jorge Eiras-Barca ◽  
Alexandre M. Ramos ◽  
Joaquim G. Pinto ◽  
Ricardo M. Trigo ◽  
Margarida L. R. Liberato ◽  
...  
Keyword(s):  
North Atlantic ◽  
North Pacific ◽  
Reanalysis Data ◽  
Water Vapour Flux ◽  
Atmospheric Rivers ◽  
The North ◽  
Explosive Cyclones ◽  
The North Atlantic ◽  
Characteristic Features ◽  
Western Side

Abstract. The explosive cyclogenesis of extra-tropical cyclones and the occurrence of atmospheric rivers are characteristic features of baroclinic atmospheres, and are both closely related to extreme hydrometeorological events in the mid-latitudes, particularly on coastal areas on the western side of the continents. The potential role of atmospheric rivers in the explosive cyclone deepening has been previously analysed for selected case studies, but a general assessment from the climatological perspective is still missing. Using ERA-Interim reanalysis data for 1979–2011, we analyse the concurrence of atmospheric rivers and explosive cyclogenesis over the North Atlantic and North Pacific Basins for the extended winter months (ONDJFM). Atmospheric rivers are identified for almost 80 % of explosive deepening cyclones. For non-explosive cyclones, atmospheric rivers are found only in roughly 40 % of the cases. The analysis of the time evolution of the high values of water vapour flux associated with the atmospheric river during the cyclone development phase leads us to hypothesize that the identified relationship is the fingerprint of a mechanism that raises the odds of an explosive cyclogenesis occurrence and not merely a statistical relationship. This insight can be helpful for the predictability of high impact weather associated with explosive cyclones and atmospheric rivers.

scholarly journals Meridional energy transport extremes and the general circulation of NH mid-latitudes: dominant weather regimes and preferred zonal wavenumbers

2022 ◽  
Author(s):  
Valerio Lembo ◽  
Federico Fabiano ◽  
Vera Melinda Galfi ◽  
Rune Graversen ◽  
Valerio Lucarini ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
General Circulation ◽  
Energy Transport ◽  
Multiple Scales ◽  
Heat Waves ◽  
Reanalysis Data ◽  
Synoptic Scale ◽  
Weather Regimes ◽  
Height Fields ◽  
Atmospheric Circulation Anomalies

Abstract. The extratropical meridional energy transport in the atmosphere is fundamentally intermittent in nature, having extremes large enough to affect the net seasonal transport. Here, we investigate how these extreme transports are associated with the dynamics of the atmosphere at multiple scales, from planetary to synoptic. We use ERA5 reanalysis data to perform a wavenumber decomposition of meridional energy transport in the Northern Hemisphere mid-latitudes during winter and summer. We then relate extreme transport events to atmospheric circulation anomalies and dominant weather regimes, identified by clustering 500 hPa geopotential height fields. In general, planetary-scale waves determine the strength and meridional position of the synoptic-scale baroclinic activity with their phase and amplitude, but important differences emerge between seasons. During winter, large wavenumbers (k = 2 − 3) are key drivers of the meridional energy transport extremes, and planetary and synoptic-scale transport extremes virtually never co-occur. In summer, extremes are associated with higher wavenumbers (k = 4 − 6), identified as synoptic-scale motions. We link these waves and the transport extremes to recent results on exceptionally strong and persistent co-occurring summertime heat waves across the Northern Hemisphere mid-latitudes. We show that these events are typical, in terms of dominant regime patterns associated with extremely strong meridional energy transports.

scholarly journals Observational Evidence of Frontal-Scale Atmospheric Responses to Kuroshio Extension Variability

2015 ◽  
Vol 28 (23) ◽  
pp. 9459-9472 ◽  
Author(s):  
Yi-Hui Wang ◽  
W. Timothy Liu
Keyword(s):  
Kuroshio Extension ◽  
Linear Regression Analysis ◽  
Surface Wind ◽  
Reanalysis Data ◽  
Satellite Observations ◽  
Climate Index ◽  
Boreal Winter ◽  
Atmospheric Response ◽  
Free Atmosphere ◽  
Low Frequencies

Abstract This study investigates the regional atmospheric response to the Kuroshio Extension (KE) using a combination of multiple satellite observations and reanalysis data from boreal winter over a period of at least a decade. The goal is to understand the relationship between KE variations and atmospheric responses at low frequencies. A climate index is used to measure the interannual to decadal KE variability, which leaves remarkable imprints on the mesoscale sea surface temperature (SST). Clear spatial coherence between the SST signals and frontal-scale atmospheric variables, including surface wind convergence, vertical velocity, precipitation, and clouds, is identified by linear regression analysis. Consistent with previous studies, the penetrating effect of the KE variability on the free atmosphere is found. The westward tilt of the atmospheric response above the KE near 500 hPa is revealed. The difference in the associations of frontal-scale air temperature and geopotential height with the KE variability between the satellite observations and the reanalysis data suggests an imperfect interpretation of frontal-scale oceanic forcing on the overlying atmosphere in the reanalysis assimilation system.

scholarly journals Recent Changes in Explosively Developing Extratropical Cyclones over the Winter Northwestern Pacific

2012 ◽  
Vol 25 (20) ◽  
pp. 7282-7296 ◽  
Author(s):  
Koki Iwao ◽  
Masaru Inatsu ◽  
Masahide Kimoto
Keyword(s):  
Reanalysis Data ◽  
Japan Meteorological Agency ◽  
Energy Budgets ◽  
Northwestern Pacific ◽  
Extratropical Cyclones ◽  
Pacific Region ◽  
Climate Data ◽  
Explosive Cyclones ◽  
Dynamical Features ◽  
Data Assimilation System

Abstract This study investigated recent changes in the characteristics of explosively developing extratropical cyclones over the northwestern Pacific region in winter from 1979/80 to 2010/11 by using reanalysis data from the Japanese 25-yr Reanalysis/Japan Meteorological Agency Climate Data Assimilation System (JRA-25/JCDAS). The results showed that the frequency of explosive cyclones increased in the northwestern Pacific region east of Japan. This increase was accompanied by a decrease in the number of slowly developing cyclones, indicating an increase in the cyclone growth rate. Moreover, most of the increased explosive cyclones east of Japan originated southwest of Japan. A comparison of the dynamical features and energy budgets of two composite cyclones in the earlier and later halves of the study period suggested that the increase was due to an enhancement of the low-level baroclinicity to the east of Japan and an increase in humidity associated with sea surface temperature warming and enhanced evaporation along the eastern shore of the Asian continent.

scholarly journals Evaluation of WRF microphysics schemes in the simulation of a squall line over IRAN using radar and reanalysis data

2021 ◽  
Vol 34 (02) ◽  
pp. 682-697
Author(s):  
Mahnaz Karimkhani ◽  
Majid Azadi ◽  
Amir Hussain Meshkatee ◽  
Abbas Ranjbar Saadatabadi
Keyword(s):  
Model Simulation ◽  
Wrf Model ◽  
Skill Score ◽  
Reanalysis Data ◽  
Squall Line ◽  
Microphysics Scheme ◽  
Vertical Extent ◽  
Simulated Precipitation ◽  
Storm Cells ◽  
Convective Cells

A squall line was recorded in Dayyer port over southwest of Iran, on 19 Mar 2017. In the present paper, we have simulated the characteristic features associated with the squall line by Weather Research and Forecasting (WRF) model using five different microphysics (MP) schemes. For validating the simulated characteristics of the squall line, the latitude-height and longitude-height cross section reflectivity and precipitation value derived from observed reflectivity gathered by Doppler Weather Radar at Bushehr, synoptic weather station data at Dayyer port along with NCEP-NCAR and ERA-INTERIM reanalyzes data were used. To verify the simulated precipitation, the Fractions Skill Score (FSS) curve was calculated. Examining the simulation results for geopotential and sea level pressure show that the model simulations using different MP schemes, agree well with the verifying reanalyzes. Also, the spatial rainfall distribution of simulations and verifying observations did not show big differences. However, there are significant differences in the details of simulations such as the maximum reflectivity of the convective cells, vertical extent of the storm cells, speed and direction of the wind, rainfall values and FSS curves. Though, all of the simulations have shown convective cells over Dayyer port at the time of occurrence of the squall line, but, only the model simulation using Lin MP scheme is consistent with the corresponding radar reflectivity and vertical extent. The FSS chart showed that the skill changes with spatial scale. Results using Lin microphysics scheme crossed the FSSuniform line at lower scales when compared to other MP schemes.

scholarly journals Impact of Arctic amplification on declining spring dust events in East Asia

2019 ◽  
Vol 54 (3-4) ◽  
pp. 1913-1935 ◽  
Author(s):  
Jun Liu ◽  
Dongyou Wu ◽  
Guangjing Liu ◽  
Rui Mao ◽  
Siyu Chen ◽  
...  
Keyword(s):  
East Asia ◽  
Northern Hemisphere ◽  
Surface Wind ◽  
Northern China ◽  
Temperature Gradients ◽  
Arctic Amplification ◽  
Dust Event ◽  
Snow Cover Extent ◽  
Spring Dust ◽  
Dust Events

AbstractDust aerosols play key roles in affecting regional and global climate through their direct, indirect, and semi-direct effects. Dust events have decreased rapidly since the 1980s in East Asia, particularly over northern China, primarily because of changes in meteorological parameters (e.g. surface wind speed and precipitation). In this study, we found that winter (December–January–February) Arctic amplification associated with weakened temperature gradients along with decreased zonal winds is primarily responsible for the large decline in following spring (March–April–May) dust event occurrences over northern China since the mid-1980s. A dust index was developed for northern China by combining the daily frequency of three types of dust event (dust storm, blowing dust, and floating dust). Using the empirical orthogonal function (EOF) analysis, the first pattern of dust events was obtained for spring dust index anomalies, which accounts for 56.2% of the variability during 1961–2014. Moreover, the enhanced Arctic amplification and stronger Northern Hemisphere annular mode (NAM) in winter can result in the anticyclonic anomalies over Siberia and Mongolia, while cyclonic anomalies over East Europe in spring. These results are significantly correlated with the weakened temperature gradients, increased precipitation and soil moisture, and decreased snow cover extent in the mid-latitude over Northern Hemisphere. Based on the future predictions obtained from the Fifth Climate Models Intercomparison Project (CMIP5), we found that the dust event occurrences may continually decrease over northern China due to the enhanced Arctic amplification in future climate.

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