what spatial scale is a typical extratropical cyclone

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How big is a typical extratropical cyclone quizlet?

What is a typical size of an area affected by a mature extratropical cyclone? Several hundred to a thousand miles across, up to a third the area of the contiguous U.S.

What is the direction of the Coriolis force acting upon the air mass?

Currents Tutorial Because the Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere. This deflection is called the Coriolis effect.

Why Coriolis force is zero at Equator?

Because there is no turning of the surface of the Earth (sense of rotation) underneath a horizontally and freely moving object at the equator, there is no curving of the object's path as measured relative to Earth's surface. The object's path is straight, that is, there is no Coriolis effect.

What is the other name term for Coriolis forces?

Coriolis force, also called Coriolis effect, in classical mechanics, an inertial force described by the 19th-century French engineer-mathematician Gustave-Gaspard Coriolis in 1835.

Which direction does Coriolis force act on the wind?

The Earth's rotation means that we experience an apparent force known as the Coriolis force. This deflects the direction of the wind to the right in the northern hemisphere and to the left in the southern hemisphere.

How does the Coriolis effect affect air travel?

In simple terms, the Coriolis Effect makes things (like planes or currents of air) traveling long distances around the Earth appear to move at a curve as opposed to a straight line. It's a pretty weird phenomenon, but the cause is simple: Different parts of the Earth move at different speeds.

Which way will the Coriolis effect deflect a parcel of air that is moving along the Earth's surface toward the equator from higher latitudes?

objects moving in the northern hemisphere get deflected to the right as you look in the direction of motion; objects moving in the southern hemisphere get deflected to the left as you look in the direction of motion; the strength of this effect, this deflection, is greater as you approach the poles; and.

How does the Coriolis effect influence the direction of moving objects How does it affect the speed of moving objects explain?

Therefore, when an object moving in a straight path is viewed from Earth, it appears to lose its course because of Earth's rotation. Simply put, the Coriolis effect makes planes and air currents that travel long distances around the earth appear to move at a curve instead of a straight line.

Storm and Cloud Dynamics

William R. Cotton, ... Susan C. van den Heever, in International Geophysics, 2011

The Science of Hydrology

Extratropical cyclones are synoptic scale low-pressure systems that occur in the middle latitudes (i.e., pole-ward of about 30° latitude) and have length scales of the order of 500–2500 km (e.g., Hakim, 2003 ).

Significant Water Vapor Imagery Features Associated With Synoptic Thermodynamic Structures

Christo G. Georgiev, ... Karine Maynard, in Weather Analysis and Forecasting (Second Edition), 2016

Mesoscale Meteorological Modeling

In extratropical cyclones, along synoptic-scale fronts and associated with tropical weather systems, precipitation is often not uniformly distributed, but occurs in well-organized mesoscale-sized bands of heavier snow or rain (e.g., Akiyama 1978 ).

CYCLONES EXTRA TROPICAL

A. Joly, ... S. Malardel, in Encyclopedia of Atmospheric Sciences, 2003

High Frequency Trends in the Isotopic Composition of Superstorm Sandy

Stephen P. Good, ... Gabriel J. Bowen, in Learning from the Impacts of Superstorm Sandy, 2015

Mesoscale Meteorological Modeling

Throughout the troposphere, an extratropical cyclone is characterized by the following during its development stage:

What causes storm surges?

Storm surges are caused primarily by high winds pushing on the ocean’s surface. The wind causes the water to pile up higher than the ordinary sea level. Low pressure at the center of a weather system also has a small secondary effect, as can the bathymetry of the body of water. It is this combined effect of low pressure and persistent wind over a shallow water body that is the most common cause of storm surge flooding problems. The term ‘storm surge’ in casual (nonscientific) use is storm tide; that is, it refers to the rise of water associated with the storm, plus tide, wave run-up, and freshwater flooding.

What are the effects of pressure gradients on Florida?

Thus, pressure gradients and wind velocity with different magnitudes affect Florida and Venice, causing enhanced flooding phenomena. Florida is typically characterized by low-frequency, very intense vertical pressure gradients that form in the ocean and moves inland with high speed in the summer season. On the contrary, Venice is characterized by medium low-frequency pressure gradients over a large area and moderate wind speed in the winter season.

How often do exceptional tides occur in Venice?

Mark’s Square ( Carbognin et al. 2010 )) statistically occur once every 4 years. Exceptional tides are caused by a combination of various factors, such as the astronomical tide, low pressure on the Tyrrhenian Sea, strong south wind (‘Scirocco’), and the Adriatic seiche. Further, two larger phenomena also contribute to the increase in the water level: eustasy and the subsidence of the Venetian Lagoon, which, together, have caused an altimetric loss of about 26 cm in the past century ( Gambolati et al. 1974; Rinaldo et al. 2008; Carbognin et al. 2010 ). High water depends on the tide cycle (the alternation of high and low tides happens every 6 h): when there is ‘acqua alta’ (high water) on the streets, it lasts only a few hours during the peak of the high tide (usually 3–4 h). Once water goes down, things go back to normality. On average, Venice is characterized by a semidiurnal tide (tidal period T = 12.4 h) and lagoon microtidal (tidal amplitude a = 0.5 m) extending over an area of roughly 550 km 2 ( Rinaldo et al. 2008; Toffolon and Lanzoni 2010 ). Four big flooding events are in the memory of Venice inhabitants ( Rinaldo 2009 ): the 194-cm high water (meteorological tidal level) event in November 1966 at 12:00 p.m., the 158-cm event in February 1986 at 00:00 a.m., the 142-cm event on 8 December 1992 at 00:00 a.m., and the 144-cm event in November 2000 at 6:00 p.m. In 1966, an unusual combination of high tides and a relentless sirocco wind sent floodwaters surging through the city’s canals and spilling over into its historic palaces and piazzas. Priceless art works were ruined, and thousands of people were trapped in their homes ( Rinaldo 2009 ). Another 5000 were left homeless. The ‘great flood’ in 1966 sparked an intense debate on how to save the World Heritage city from the ravages of flooding ( Gambolati et al. 1974; Harleman et al. 2000; Bras et al. 2001; Pirazzoli and Umgiesser 2003; Comerlati et al. 2004; Castelletto et al. 2008; Rinaldo 2009 ). The final solution was the design and construction of the ‘Mo.S.E’ (‘Modulo Sperimentale Elettromeccanico’; in English, ‘Experimental Electromechanical Module’) consisting of rows of mobile gates able to isolate the Venetian Lagoon from the Adriatic Sea when the tide reaches above an established level (110 cm) and up to a maximum of 3 m. The Mo.S.E. is going to be in fully operative in 2012 ( Carbognin et al. 2010 ). We considered the 1966, 1986, 1992, and 2000 events in our analysis. Two other events, which happened on 1 December 2008 and 25 December 2009, registered a tidal level of 156 cm and 145 cm, respectively. However, the latter events were not considered for the lack of wind data. Figures 2 and 3 show the global circulation patterns of pressure and wind velocity for the 1966 high-water event.

Who created the first modern meteorology model?

Modern meteorology was founded by Vilhelm Bjerknes and his ‘Bergen school’ in Norway. He visualized the atmosphere as consisting of three-dimensional air masses moving around the globe, varying in temperature, density, and humidity. An important step was achieved by Bjerknes' son Jacob, who developed a model of the extratropical cyclone and how it moves. Bjerknes was able to exploit an existing military observational network for weather forecasting in western Norway, which enabled him to follow the movement of the cyclones. The model also brought him considerable popular support in the area. The major breakthrough occurred in 1919, when the concept of the ‘polar front’ was born. It would take several decades before the world's meteorologists were persuaded to ‘see’ a battle line, separating cold air masses from the north and warm air masses from the south. Bjerknes thought that this line stretched along the entire Atlantic, or indeed around the entire globe. Along the polar front, the cyclones, or low-pressure areas, were formed, which would hit the coasts of Europe with rain and storm. Bjerknes placed weather forecasting on a new footing, as the analysis of polar fronts for the purpose of forecasting relied on large networks for atmospheric data gathering (Friedman, 1989; Edwards, 2010 ).

Can a tropical cyclone cause flooding?

Although the winds can cause serious damage, including broken building windows, the majority of damage is a result of flooding during and after the tropical cyclone.

What scales are used to measure tropical cyclones?

Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index .

What is the wind speed of a tropical cyclone?

Any tropical cyclone that develops within the North Indian Ocean between 100°E and 45°E is monitored by the India Meteorological Department (IMD, RSMC New Delhi). Within the region a tropical cyclone is defined as being a non frontal synoptic scale cyclone, that originates over tropical or subtropical waters with organized convection and a definite cyclonic surface wind circulation. The lowest official classification used in the North Indian Ocean is a Depression, which has 3-minute sustained wind speeds of between 17 and 27 kn (20–31 mph; 31–49 km/h). Should the depression intensify further then it will become a Deep Depression, which has winds between 28 and 33 kn (32–38 mph; 50–61 km/h). The system will be classified as a cyclonic storm and assigned a name by the IMD, if it should develop gale-force wind speeds of between 34 and 47 kn (39–54 mph; 62–88 km/h). Severe Cyclonic Storms have storm force wind speeds of between 48 and 63 kn (55–72 mph; 89–117 km/h), while Very Severe Cyclonic Storms have hurricane-force winds of 64–89 kn (73–102 mph; 118–166 km/h). Extremely Severe Cyclonic Storms have hurricane-force winds of 90–119 kn (166–221 km/h, 104–137 mph). The highest classification used in the North Indian Ocean is a Super Cyclonic Storm, which have hurricane-force winds of above 120 kn (138 mph; 222 km/h).

What are the different types of tropical cyclones?

Between 1924 and 1988, tropical cyclones were classified into four categories: depression, deep depression, cyclonic storms and severe cyclonic storms. However, a change was made during 1988 to introduce the category "severe cyclonic storm with core of hurricane winds" for tropical cyclones, with wind speeds of more than 64 kn (74 mph; 119 km/h). During 1999 the categories Very Severe Cyclonic Storm and Super Cyclonic Storm were introduced, while the severe cyclonic storm with a core of hurricane winds category was eliminated. During 2015 another modification to the intensity scale took place, with the IMD calling a system with 3-minute maximum sustained wind speeds between 90 and 119 kn (166–221 km/h, 104–137 mph): an extremely severe cyclonic storm.

How is cyclone energy calculated?

It is calculated by taking the squares of the estimated maximum sustained velocity of every active tropical storm (wind speed 35 knots or higher) at six-hour intervals. The numbers are usually divided by 10,000 to make them more manageable. The unit of ACE is 10 4 kn 2, and for use as an index the unit is assumed. As well as being squared for ACE, wind speed can also be cubed, which is referred to as the Power Dissipation Index (PDI).

What are tropical storms classified as?

Tropical cyclones or subtropical cyclones that exist within the North Atlantic Ocean or the North-eastern Pacific Ocean are classified as either tropical depressions or tropical storms. Should a system intensify further and become a hurricane, then it will be classified on the Saffir–Simpson hurricane wind scale, and is based on the estimated maximum sustained winds over a 1-minute period. In the Western Pacific, the ESCAP/WMO Typhoon Committee uses four separate classifications for tropical cyclones that exist within the basin, which are based on the estimated maximum sustained winds over a 10-minute period.

How many classifications are there for the North Indian Ocean?

The India Meteorological Department 's scale uses 7 different classifications for systems within the North Indian Ocean, and are based on the systems estimated 3-minute maximum sustained winds. Tropical cyclones that develop in the Southern Hemisphere are only officially classified by the warning centres on one of two scales, ...

Where do tropical cyclones occur?

Tropical cyclones that occur within the Northern Hemisphere to the east of the anti-meridian, are officially monitored by either the National Hurricane Center or the Central Pacific Hurricane Center. Within the region a tropical cyclone is defined to be a warm cored, non-frontal synoptic disturbance, that develops over tropical or subtropical waters, with organized atmospheric convection and a closed well defined circulation centre. The region also defines a subtropical cyclone as a non-frontal low pressure disturbance, that has the characteristics of both tropical and extratropical cyclones. Once either of these classifications are met, then advisories are initiated and the warning centers will classify the system as either a tropical or subtropical depression, if the one-minute sustained winds estimated or measured as less than 34 kn (38 mph; 62 km/h).

How to view extratropical cyclones?

In the 1960s, satellites began to be used for meteorological purposes and it became possible to view extratropical cyclones from above by their distinctive cloud signatures. From these cloud signatures, upper level flow features can be inferred and, when combined with analysis data, are a powerful tool for understanding extratropical cyclogenesis [e.g., Zillman and Price, 1972; Browning, 1990; Evans et al., 1994 ]. This is especially useful for deep cyclones (those with low central pressure), since cloud features become more distinct in deeper cyclones (when considering cyclones at any point in their life cycle) [ Field and Wood, 2007 ]. Satellite classification has mostly been used to classify the cyclogenesis as an aid to forecasting [e.g., Zillman and Price, 1972; Reed, 1979; Reed and Blier, 1986a, 1986b; Evans et al., 1994; Young, 1993 ]. Others have used satellite data to look at different cyclone life cycles [e.g., Troup and Streten, 1972] or relate cloud features to cyclone intensities [ Junker and Haller, 1980 ].

Why are extratropical cyclones important?

It is therefore important that our current state-of-the-art climate models are able to realistically represent these features , in order that we can have confidence in how they are projected to change in a warming climate . Despite the observation that these cyclones are extremely variable in their structure and features, there have, over the years, been numerous attempts to classify or group them. Such classifications can provide insight into the different cloud structures, airflows, and dynamical forcing mechanisms within the different cyclone types. This review collects and details as many classification techniques as possible, and may therefore act as a reference guide to classifications. These classifications offer the opportunity to improve the way extratropical cyclone evaluation in climate models is currently done by giving more insight into the dynamical and physical processes that occur in climate models (rather than just evaluating the mean state over a broad region as is often done). Examples of where these ideas have been used, or could be used, are reviewed. Finally, the potential impacts of future climate changes on extratropical cyclones are detailed. The ways in which the classification techniques could improve our understanding of future changes in extratropical cyclones and their impacts are given.

What is the primary mechanism by which extratropical cyclones develop?

In almost all discussions on extratropical cyclones, reference will be made to baroclinic instability or baroclinicity. This is the primary mechanism by which extratropical cyclones develop and so it deserves some attention in a review such as this. Another important concept is the so-called PV thinking [ Hoskins et al., 1985 ], and a brief introduction is given here. Readers familiar with these concepts may wish to skip to section 3 .

How do extratropical cyclones affect the environment?

One of the major impacts of extratropical cyclones that has received a lot of attention (in Europe especially) is the wind damage. Synoptic-scale variability in surface winds is strongly related to the midlatitude storm tracks and the regions of maximum atmospheric instability [ Booth et al., 2010 ]. The winds associated with extratropical cyclones can be extreme [e.g., Nissen et al., 2010; Raveh-Rubin and Wernli, 2015] and can cause widespread damage over Europe (and elsewhere) and thus are a very costly natural hazard [e.g., Fink et al., 2009 ]. Losses can be estimated using information on the daily maximum gust wind speeds [ Klawa and Ulbrich, 2003 ]. The gusts themselves can be hard to measure and predict; therefore, methods have been developed to estimate them from larger-scale wind information using dynamical and statistical approaches [ Born et al., 2012; Haas and Pinto, 2012 ]. Roberts et al. [ 2014] produced a catalog of extratropical cyclones with strong winds over Europe containing information on 3 s gusts obtained from high-resolution modeling. The winds associated with extratropical cyclones (especially on the U.S. East Coast) can also cause extensive damage from large storm surges [ Colle et al., 2015, and references therein].

What are extratropical storms?

Extratropical cyclones (also called midlatitude storms) are a vital component of the global circulation [e.g., Chang et al., 2002 ], transporting huge amounts of moisture and energy . The passage of these systems is responsible for much of the day-to-day variability of weather in the midlatitudes, with cyclones and fronts bringing up to 90% of the precipitation [ Catto et al., 2012; Hawcroft et al., 2012] including extremes (for example, as defined by events above the 99th percentile [ Pfahl and Wernli, 2012; Catto and Pfahl, 2013 ]) and causing damage associated with strong winds [e.g., Browning, 2004; Leckebusch et al., 2006 ]. It is therefore of great importance that climate models are able to represent these features so that we can have confidence in projections of how these systems may change in a future climate.

How are extratropical storm tracks evaluated?

The first is using Eulerian measures such as mean sea level pressure variability or eddy kinetic energy [e.g., Blackmon et al., 1977 ]; and the other is the objective identification and tracking of individual cyclones [e.g., Neu et al., 2013 ], which allows a comparison of track statistics and spatial distribution. These methods have been used to show that climate models capture the characteristics of storm tracks [e.g., Ulbrich et al., 2008; Catto et al., 2011; Colle et al., 2013; Zappa et al., 2013] and show improvements over earlier models [ Löptien et al., 2008 ]. The exact systems identified by different objective tracking methods can differ [ Neu et al., 2013 ], and care needs to be taken when comparing results from different studies. The most recent Intergovernmental Panel on Climate Change (IPCC) report (AR5) summarized the evaluation of extratropical storm tracks and cyclones [ Flato et al., 2013] and found that overall the representation of these features in climate models is improving over time.

Where are synoptic cyclones generated?

The conceptual model of cyclogenesis and cyclone life cycles following the work of the Bergen School suggests that synoptic cyclones are generated in the baroclinic environment of the polar front. A second proposed mechanism for cyclogenesis was tested by Petterssen et al. [ 1955] as the hypothesis that “cyclonic development at sea level occurs when and where an area of positive vorticity advection in the upper troposphere becomes superimposed upon a frontal zone at sea level.” Petterssen and Smebye [ 1971] looked in more detail at these two mechanisms and developed a classification of them based on the relative contribution of upper level and lower level forcing in the development of the cyclones. The study of Deveson et al. [ 2002] attempted to quantify the upper level and lower level forcing present through the life cycle in a number of cyclones observed during FASTEX [ Joly et al., 1997, 1999 ]. This was done by using a height-attributable version of the quasi-geostrophic omega equation—this determines the forcing of ascent and descent at 700 hPa attributable to both thermal advection at low levels ( L) and vorticity advection at upper levels ( U ). The ratio of this forcing ( U / L) is used as a measure of the relative forcing, and the horizontal distance between the maximum upper level and lower level forcing is referred to as the vertical tilt. As well as the two types identified by Petterssen and Smebye [ 1971 ], Deveson et al. [ 2002] also identified a third type. The three types are as follows:

What are the extratropical cyclones?

Extra-tropical cyclones (also referred to as mid-latitude cyclones) are a fundamental part of the atmospheric circulation in the mid-latitudes due to their ability to transport large amounts of heat, moisture, and momentum.

How are idealized studies used to study the dynamics of extratropical cyclones?

Idealized studies have been used extensively in the past to understand the dynamics of extra-tropical cyclones. For example, baroclinic wave simulations have been performed to understand the dynamics of extra-tropical cyclones and fronts in the current climate (e.g. Simmons and Hoskins , 1978; Thorncroft et al. , 1993; Schemm et al. , 2013; Sinclair and Keyser , 2015). More recently baroclinic life cycle experiments have also been used to assess, in a highly controlled simulation environment, how the dynamics and structure of extra-tropical cyclones may respond to climate change. Given that diabatic processes, and in particular latent heating due to condensation of water vapour, play a large role in the evolution of extra-tropical cyclones (e.g. Stoelinga , 1996), many idealized studies have focused on how the intensity and structure of extra-tropical cyclones change as temperature and moisture content are varied (e.g Boutle et al. , 2011; Booth et al. , 2013, 2015; Kirshbaum et al. , 2018). These studies show that when moisture is increased from low levels to values typical of today's climate, extra-tropical cyclones become more intense. This is a relatively robust result across many studies and can be understood to be a consequence of an induced low-level cyclonic vorticity anomaly beneath a localized maximum in diabatic heating ( Hoskins et al. , 1985). However, when temperatures and moisture content are increased to values higher than in the current climate, baroclinic life cycle experiments show divergent results. For example, Rantanen et al. ( 2019) found that uniform warming acts to decrease both the eddy kinetic energy and the minimum surface pressure of the cyclone, whereas Kirshbaum et al. ( 2018) showed that for large temperature increases with constant relative humidity the eddy kinetic energy decreases whereas the minimum surface pressure increases. Furthermore, Tierney et al. ( 2018) documented non-monotonic behaviour of the cyclone intensity in terms of both maximum eddy kinetic energy and minimum mean surface pressure with increasing temperature.

How much will the temperature increase in the SST4 experiment?

At low levels, the increase in temperature in the SST4 experiment relative to CNTL is typically of the order of 4 K, which is of similar magnitude to the enforced increase in SSTs. This temperature increase can be put into context by comparison with predictions from CMIP5 models. Under the RCP8.5 scenario, CMIP5 models predict that global mean near-surface temperatures will increase by 2.6 to 4.8 K by the end of the 21st century relative to the 1986–2005 mean. Hence, the aqua-planet simulations performed here have a degree of warming that could be expected to occur by the end of the 21st century under large greenhouse gas emissions.

How are cyclone tracks used in a composite?

The cyclone tracks are then used as the basis to create composites of extra-tropical cyclones following the same method as Catto et al. ( 2010) and Dacre et al. ( 2012). Rather than creating a composite of all identified extra-tropical cyclones, only the 200 strongest cyclones in terms of their maximum 850 hPa relative vorticity are selected from the CNTL and SST4 experiments, and composites of a range of meteorological variables are created for these extreme cyclones at different offset times relative to the time of maximum intensity ( t=0 h). Each composite is created by first determining the values of the relevant meteorological variable, at each offset time, and for each individual cyclone to be included in the composite, on a spherical grid centred on the cyclone centre. The meteorological values are thus interpolated from the native model longitude–latitude grid to this spherical grid, which has a radius of 12 ∘ and is decomposed into 40 grid points in the radial direction and 360 grid points in the angular direction. To reduce smoothing errors, the cyclones are rotated so that all travel due east. To obtain the cyclone composite, the meteorological values on the radial grid are averaged at each offset time. Thus, the composite extra-tropical cyclone is the simple arithmetic mean of the 200 individual, rotated cyclones.

What are the disadvantages of baroclinic life cycle?

A disadvantage of baroclinic life cycle experiments is that often only one cyclone and its response to environmental changes are considered, whereas in reality there is considerable variability in the structure, intensity, size, and lifetime of extra-tropical cyclones. Recent baroclinic life cycle studies have suggested that the response of cyclones to warming in these types of simulations may depend on how the simulation is configured ( Kirshbaum et al. , 2018). An alternative, yet still idealized approach, is to perform multi-year aqua-planet simulations in which thousands of extra-tropical cyclones develop and can be analysed. A benefit of this approach compared to baroclinic life cycle experiments is that experimental set-up and initial conditions have a much weaker influence on the evolution of the model state and thus on the structure and size of the simulated extra-tropical cyclones. Pfahl et al. ( 2015) used a simplified general circulation model in an aqua-planet configuration with a slab ocean to assess how the intensity, size, deepening rates, lifetime, and spatial structure of extra-tropical cyclones respond when the longwave optical thickness is varied in such a way that the global mean near-surface air temperature varies from 270 to 316 K. Their main result was that changes in cyclone characteristics are relatively small except for the intensity of the strongest cyclones, which considerably increased in strength with warming. However, this study was based on an idealized general circulation model, which contained simplified physics parameterizations; for example, the large-scale microphysical parameterization only considers the vapour–liquid phase transition.

What is the Omega equation?

The omega equation is a diagnostic equation from which the vertical motion ( ω) resulting from different physical processes can be calculated. Different forms of the omega equation with differing degrees of complexity exist and range from the simplest “standard” quasi-geostrophic (QG) form with friction and diabatic heating neglected ( Holton and Hakim , 2012) to the complex generalized omega equation ( Räisänen , 1995; Rantanen et al. , 2017). Here we solve the following version of the QG omega equation in pressure ( p) coordinates:

How does the troposphere respond to warming?

1. The temperature increases everywhere in the troposphere with the largest warming in the tropical upper troposphere , where temperature increases by up to 7 K. Cooling takes place in the polar stratosphere, which acts to increase the upper-level meridional temperature gradient. The tropopause height increases at most latitudes with warming. The spatial pattern of these changes in zonal mean temperature is similar to those found in more complex climate models (e.g. Fig. 12.12, Collins et al. , 2013). However, the warming in the low to mid-troposphere is relatively uniform with latitude. The lack of enhanced warming in the Northern Hemisphere polar regions (polar amplification) and hence no decrease in low-level baroclinicity is the most notable difference in the atmosphere's response to warming in these aqua-planet experiments compared to in complex climate model simulations.

How are cyclones clustered?

This means that in this type of analysis cyclones are clustered according to their track location, orientation or genesis region. For example, cyclones travelling in similar locations can be used to identify the major storm tracks 9. Furthermore, within a single storm track, cyclones can be clustered according to whether they travel preferentially in a zonal, tilted or meridional orientation 10. An early example of this approach is the cyclone paths based on early weather data/charts 11, 12. van Bebber 12 related particular cyclone paths with specific weather impacts, most notably meridionally travelling Mediterranean cyclones (Vb cyclones), which can lead to heavy precipitation in the Alpine region. More recently, clustering by locality has been applied to cyclone tracks to analyse their links to the large-scale flow 10, 13, 14. For example, Gaffney et al. 13 found that, in reanalysis data, wintertime North Atlantic cyclone tracks occurring during the positive phase of the North Atlantic Oscillation (NAO) are preferentially in the SW-NE orientated cluster, whereas for the negative NAO phase they are typically more zonal and slower moving.

What is serial clustering?

Serial clustering of extratropical cyclones describes the passage of multiple cyclones over a fixed location within a given time period. Such periods often result in high precipitation totals and accumulated wind damage, leading to large societal and financial impacts. Here, we define the terminology to differentiate between several types of cyclone clustering and review multiple approaches used to quantify it. We provide an overview of current research activities including a review of serial cyclone clustering climatologies used to identify where clustering occurs. We review the dynamical mechanisms determining when and why serial cyclone clustering occurs for different timescales of interest. On daily timescales, serial cyclone clustering is often associated with a cyclone family and secondary cyclogenesis mechanisms. At longer timescales, active or inactive seasons are often associated with persistent large-scale flow patterns and their interaction with successive Rossby wave-breaking events. Finally, we discuss the knowledge gaps and current research opportunities.

What happens if the Rockies tilt east?

In addition, if this tilt occurs east of the Rockies in the U.S., there will be CAA aloft and warm, moist air at the surface • With the development of extratropical cyclones, it is most common for upper-level troughs to be positively tilted initially and end up neutrally or negatively tilted.

What is the occluded stage?

The occluded stage is characterized by an increase in the occlusion, which cuts off the supply of warm, moist air and leads to dissipation.

What are jet streaks?

Jet Streaks. • Right entrance and left exit regions of jet streaks are preferred areas of storm formation and extratropical cyclone development. Air Masses. • Air masses are large bodies of air that take on the properties of the underlying surface • Air masses are classified according to their location of origin – essentially their temperature ...

Overview

Background

Tropical cyclones are defined as being warm cored, non-frontal synoptic cyclones, that develop over tropical or subtropical waters, with organized atmospheric convection and have a definite cyclonic surface wind circulation. They are classified by the wind speeds located around the circulation centre and are ranked, by the World Meteorological Organization's Regional Specialized Meteorological Centers on one of five tropical cyclone scales. The scale used for a particular tro…

Atlantic, Eastern and Central Pacific

Western Pacific

North Indian Ocean

South-West Indian Ocean

Australia and Fiji

Alternative scales