Dominant transport pathways in an atmospheric blocking event

Enrico Ser-Giacomi; Ruggero Vasile; Irene Recuerda; Emilio Hernández-García; Cristóbal López

doi:10.1063/1.4928704

3D Variable Coefficient KdV Equation and Atmospheric Dipole Blocking

Advances in Meteorology ◽

10.1155/2018/4329475 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 2

Author(s):

Juanjuan Ji ◽

Yecai Guo ◽

Lanfang Zhang ◽

Lihua Zhang

Keyword(s):

Analytical Solution ◽

Variable Coefficient ◽

Exact Analytical Solution ◽

Kdv Equation ◽

Direct Method ◽

Dimensional Space ◽

Vertical Direction ◽

Atmospheric Blocking ◽

Dimensional Variable ◽

Blocking Event

A (2 + 1)-dimensional variable coefficient Korteweg-de Vries (3D VCKdV) equation is first derived in this paper by means of introducing 2-dimensional space and time slow-varying variables and the multiple-level approximation method from the well-known barotropic and quasi-geostrophic potential vorticity equation without dissipation. The exact analytical solution of the 3D VCKdV equation is obtained successfully by making use of CK’s direct method and the standard Zakharov–Kuznetsov equation. By some arbitrary functions and the analytical solution, a dipole blocking evolution process with twelve days’ lifetime is described, and the result illustrates that the central axis of the dipole is no longer perpendicular to the vertical direction but has a certain angle to vertical direction. The comparisons with the previous researches and Urals dipole blocking event demonstrate that 3D VCKdV equation is more suitable for describing the complex atmospheric blocking phenomenon.

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Identification and characterization of an atmospheric blocking event over the South Pacific from August 31 to September 05, 2019

10.5194/egusphere-egu21-10258 ◽

2021 ◽

Author(s):

Jamyle Magalhães ◽

Ana Cristina Pinto de Almeida Palmeira

Keyword(s):

South Pacific ◽

Zonal Flow ◽

Horizontal Resolution ◽

Atmospheric Blocking ◽

Subjective Analysis ◽

Weather Forecasts ◽

Zonal Index ◽

Blocking High ◽

Blocking Event

<p>Atmospheric circulation in mid-latitudes is characterized by a westerlies zonal flow. On blocking conditions, this flow is interrupted by a large almost-stationary anticyclone. This situation, there is a splitting of the jet stream, what modify zonal flow pattern and change the normal eastward displacement of transients. There are two blocking types frequently observed in South Hemisphere (SH): dipole type blocking &#8211; occurs when a cut-off low is located north of the anticyclone, which characterize a dipole; omega type blocking &#8211; occurs when there is an arrangement of two cut-off lows and the blocking high like Greek letter &#937; (omega, inverted in SH). First, the subjective methods were created to identify these systems, later, aiming at numerical modeling, the objective methods, called zonal index, were created. Thus, the purpose of this study was to identify, through subjective and objective methods, a blocking system that occurred over South Pacific, on the west coast of South America, from August 31 to September 05, 2019. In this study, surface synoptic chart from Navy Hydrography Center (NHC) and images from Geostationary Operational Environmental Satellite (GOES-16) in channel 13 (infrared) were used. In addition, data from Era5 reanalysis of the European Centre for Medium-Range Weather Forecasts (ECMWF), with a horizontal resolution of 0.25&#176;, were used to elaborate meteorological fields and zonal index calculation. The identification criteria proposed by Casarin and Kousky (1982) were used for subjective analysis, and the Leje&#241;as (1984) for objective one. The analyzed fields indicate that the system had persisted for six days. In this period, the flow was split, the blocking high didn&#8217;t move more 25&#186; of longitude and the zonal index remained negative, what satisfied all criteria used. Therefore, this event was characterized as atmospheric blocking of dipole kind.</p>

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Variations of carbon monoxide in the atmosphere during the atmospheric blocking event over European Russia in summer of 2010 (according to AIRS data)

Оптика атмосферы и океана ◽

10.15372/aoo20170305 ◽

2017 ◽

Keyword(s):

Carbon Monoxide ◽

European Russia ◽

Atmospheric Blocking ◽

Blocking Event

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The predictability of northern hemispheric blocking using an ensemble mean forecast system

10.32469/10355/62074 ◽

2017 ◽

Author(s):

◽

Devondria D. Reynolds

Keyword(s):

Large Scale ◽

Weather Conditions ◽

Atmospheric Blocking ◽

Weather Extremes ◽

University Of Missouri ◽

Knowing How ◽

Weather Patterns ◽

Intensity Index ◽

Temperature And Precipitation ◽

Blocking Event

Some weather extremes can be the result of atmospheric blocking. Like atmospheric patterns that tend to repeat themselves, atmospheric blocking leads to the stagnation of weather patterns. This repetition can last for several days to weeks. These large-scale quasi-stationary mid-latitude flow regimes can result in significant temperature and precipitation anomalies in the regions that the blocking event impacts. Being able to predict periods of anomalous weather conditions due to atmospheric blocking is a major problem for medium-range forecasting. Analyzing the NCEP Ensemble 500-mb pressure heights (240 hrs.) ten-day forecasts and using the University of Missouri blocking archive to identify blocking event, the duration of blocks, intensity prediction in comparison to observed blocks. Comparing these differences over a oneyear period across the Northern Hemisphere has shown the possibility for improved predictability of these blocks and their intensity. Having a better understanding of knowing how long each block will last and their associated anomalies can help society prepare for the damage they can cause. Knowing how to correctly identify blocks is important in improving forecast issues. Lastly, it is demonstrated that the Integrated Regional Enstrophy (IRE) for these events correlates with a block intensity index (BI).

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