Radar Observations of a Frontal Storm

The development of frontal precipitation as observed by radar is illustrated by data taken on a particular storm. This storm presents a typical sequence of precipitation patterns found to be associated with a warm front and a following cold front.

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Precipitation associated with extra-tropical cyclones: response to uniform global warming and to polar amplification

10.5194/ems2021-340 ◽

2021 ◽

Author(s):

Victoria Sinclair ◽

Jennifer Catto

Keyword(s):

Tropical Cyclones ◽

Cold Front ◽

Precipitation Pattern ◽

Large Sample Size ◽

Precipitation Patterns ◽

Polar Amplification ◽

Warm Front ◽

Precipitation Decrease ◽

The Future ◽

The Relationship

<p>Extra-tropical cyclones constitute a large part of the circulation in the mid-latitudes and can lead to high impact weather. Therefore, it is beneficial to society to determine how these storms and their associated weather may change in the future. We focus on precipitation associated with extra-tropical cyclones (ETCs) and first aim to determine how the relationship between dynamical measures (e.g. maximum relative vorticity) of cyclone intensity and ETC related precipitation will response to climate change. Secondly, because not all ETCs are the same, we investigate whether the relationship between ETC precipitation and ETC intensity depends on the type of cyclone. Finally, we examine whether certain types of ETCs, in terms of their precipitation patterns, are likely to become more or less common in the future. We address these questions using aqua-planet simulations performed using an atmosphere-only model (OpenIFS) with fixed sea surface temperatures (SSTs). The simulations are run at T255 resolution (~ 80 km) and are 10 years long which generates a very large sample size of ETCs (> 14,000). The three simulations differ only in terms of the specific SST distribution: a control simulation is performed with the well-known &#8220;QObs&#8221; SST distributions, the second simulation has a uniform warming of 4K applied everywhere, and the third simulation is a polar amplification experiment with a 5K warming poleward of 45 degrees. In each experiment, all ETCs are objectively identified and tracked. Different types of cyclones are identified by applying k-means clustering to the precipitation pattern within a 12-degree radius of the cyclone centre. In all three experiments, more dynamically intense ETCs have more precipitation associated with them but there is considerable spread. Uniform warming strengthens this relationship and hence a ETC of a certain dynamical intensity will have more precipitation associated with it in a warmer climate. Clustering identifies 4 distinct types of ETCs in terms of their precipitation patterns: ETCs with most precipitation associated with the warm front; ETCs dominated by cold front precipitation; ETCs dominated by cyclone-centred precipitation; ETCs with very little precipitation. All 4 cyclone types appear in each experiment. Uniform warming causes a notable increase in the number of ETCs with precipitation concentrated on the warm front and a decrease in the number of ETCs with weak precipitation. In contrast, polar warming causes a large increase in the number of ETCs with weak precipitation and ETCs dominated by cold front precipitation decrease in number. These results, and others, will be presented along with dynamical interpretations.</p>

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Associations of weather fronts with pig reproduction and mortality

10.1101/2021.02.01.428991 ◽

2021 ◽

Author(s):

Tamás Reibling ◽

Linnea Hagstrand ◽

Ákos Maróti-Agóts ◽

Zoltán Barcza ◽

Norbert Solymosi

Keyword(s):

Scientific Literature ◽

Cold Front ◽

Animal Health ◽

Population Based ◽

Temperature Decrease ◽

Atmospheric Front ◽

Quantitative Studies ◽

Warm Front ◽

The Impact ◽

Weather Fronts

ABSTRACTFarmers and practising veterinarians have long suspected the impact of weather fronts on production and animal health. A common impression is that sows will farrow earlier in connection with a cold front. There might be a correlation between daily mortality and the occurrence of a strong atmospheric front. Population-based quantitative studies on weather fronts’ effects on animal health and production are very sparse in the scientific literature. In this study, the associations between the weather fronts and daily farrowing incidence, the pregnancy length and the daily death incidence were analysed. The results show that cold front increased the odds of more than daily six farrowings on the day of the front (with at least 3°C cooling OR: 4.79, 95%CI: 1.08-21.21, p=0.039). On the day of the front, with at least 3°C temperature change both the cold and the warm front increased the odds of the farrowing on the day ≥ 118th day of the gestation (OR: 3.10, 95%CI: 1.04-9.30, p=0.43 and OR: 4.39, 95%CI: 1.73-11.15, p=0.002, respectively). On the day after the day of front, the odds of farrowing on the ≤ 113th day of gestation are increased, if the temperature decrease was at least 2°C the OR: 2.30 (95%CI: 1.04-5.06, p=0.039). On the day after the warm front with at least 1°C temperature increase the odds of more than daily three deaths is increased (OR: 5.44, 95%CI: 1.23-24.05, p=0.025).

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P6146Atmospheric front patterns and acute cardiovascular diseases, a new perspective in the cardiovascular threat of global climate change

European Heart Journal ◽

10.1093/eurheartj/ehz746.0752 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

N Boussoussou ◽

M Boussoussou ◽

M Rakovics ◽

L Entz ◽

A Nemes

Keyword(s):

Climate Change ◽

Cardiovascular Diseases ◽

Global Climate Change ◽

Cold Front ◽

Global Climate ◽

Atmospheric Parameters ◽

Atmospheric Front ◽

Warm Front ◽

The Future ◽

The Impact

Abstract Background There is substantial evidence that the health threat of global climate change is real and it could be a medical emergency. The impact of climate change on health is mediated through atmospheric parameters which are direct environmental stressors on the human body and have a potential cardiovascular (CV) morbidity and mortality effect. Acute cardiovascular diseases (ACVDs) are already major public health issues and in the future unfavourable atmospheric situations, such as increasingly volatile fronts and their negative effects can further increase this problem. Despite evidence about the importance of different atmospheric parameters on health outcomes, there have been few results for atmospheric front patterns' CV effects. Weather fronts are the most complex atmospheric phenomena therefore these atmospheric parameters might have the greatest influence on ACVDs. Purpose We aimed to explore the effects of atmospheric front patterns on ACVDs. Methods A time series Poisson-regression analysis was used to analyse 6499 ACVD hospital admissions, during a five-year period (2009–2013), in light of front patterns. Covariates were three-day (target day and the two previous days) front sequence patterns comprised of the five major front types (no front, warm front, occluded front, cold front, stationary front). Relative risk (RR) estimates for front effects were adjusted for seasonality. The relationship on all ACVDs combined and separately on patient groups by major CV risk factors (hypertension, hyperlipidaemia, diabetes, previous CV diseases) was examined. Results We found that in general, front patterns containing warm front days had a detrimental effect. A warm front, when followed by two days with no fronts present, increased RR by 46% (CI: 4–89%, p=0,015). Cold fronts however were protective. A no front – cold front – occluded front pattern corresponded to a 28% (CI: 8–49%, p=0,037) decrease in RR, with this pattern being present in 1.1% of all days of the study period. Out of the group specific results an occluded front, following days with no fronts present, showed to have the largest effect on hyperlipidaemic patients, increasing RR by 144% (CI: 51–295%, p<0.001). Conclusions This work provides both independent evidence of front patterns' CV effects and a novel tool to investigate and help the understanding of complex associations between atmospheric fronts and ACVDs. The importance of our findings is growing in the context that extreme atmospheric conditions and changes are likely to become more common in the future as a result of climate change. Medical meteorology may open up a new horizon and become an important field of preventive cardiology in the future. In conclusion, a better understanding of atmospheric front effects is of particular importance in order to help identify possible targets for future prevention strategies.

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5. Weather systems

10.1093/actrade/9780199571314.003.0005 ◽

2017 ◽

Author(s):

Storm Dunlop

Keyword(s):

High Pressure ◽

Cold Front ◽

Low Pressure ◽

Extratropical Cyclones ◽

British Isles ◽

Polar Lows ◽

Atmospheric Rivers ◽

Warm Sector ◽

Warm Front ◽

Low Pressure Systems

At temperate latitudes, such as those of the British Isles, the most significant changes in the weather, with major changes in wind strength and direction, as well as rainfall, are associated with the passage of depressions (low-pressure systems), more formally known as extratropical cyclones. ‘Weather systems’ describes the development of depressions, the different features within them (the warm front, the warm sector, the cold front, and the occluded front), and the likely weather produced. It also looks at isolated fronts, the sudden deepening of depressions, thermal and polar lows, atmospheric rivers, and the much quieter weather of high-pressure systems.

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The Variability of Cold Front Precipitation

Bulletin of the American Meteorological Society ◽

10.1175/1520-0477-37.9.447 ◽

1956 ◽

Vol 37 (9) ◽

pp. 447-453 ◽

Cited By ~ 2

Author(s):

James M. Austin ◽

R. H. Blackmer

Keyword(s):

Cold Front ◽

Radar Data ◽

Precipitation Variability ◽

Precipitation Patterns ◽

Cold Fronts ◽

Negative Results ◽

Precipitation Type

Radar data are utilized to describe the precipitation patterns with 30 summertime cold fronts in the vicinity of Cambridge, Massachusetts. An attempt to relate the precipitation type and coverage to synoptic parameters which can be obtained from the conventional meteorological charts yielded essentially negative results. Possible causes of the precipitation variability are discussed.

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Environment and morphology of mesoscale convective systems associated with the Changma front during 9–10 July 2007

Annales Geophysicae ◽

10.5194/angeo-30-1235-2012 ◽

2012 ◽

Vol 30 (8) ◽

pp. 1235-1248 ◽

Cited By ~ 15

Author(s):

J.-H. Jeong ◽

D.-I. Lee ◽

C.-C. Wang ◽

S.-M. Jang ◽

C.-H. You ◽

...

Keyword(s):

Cold Front ◽

Low Pressure ◽

Convective Cell ◽

Mesoscale Convective Systems ◽

Low Level ◽

Convective Systems ◽

Warm Front ◽

Synoptic Conditions ◽

Mesoscale Convective ◽

Convective Cells

Abstract. To understand the different environment and morphology for heavy rainfall during 9–10 July 2007, over the Korean Peninsula, mesoscale convective systems (MCSs) that accompanied the Changma front in two different regions were investigated. The sub-synoptic conditions were analysed using mesoscale analysis data (MANAL), reanalysis data, weather charts and Multi-functional Transport Satellite (MTSAT-IR) data. Dual-Doppler radar observations were used to analyse the wind fields within the precipitation systems. During both the case periods, the surface low-pressure field intensified and moved northeastward along the Changma front. A low-level warm front gradually formed with an east-west orientation, and the cold front near the low pressure was aligned from northeast to southwest. The northern convective systems (meso-α-scale) were embedded within an area of stratiform cloud north of the warm front. The development of low-level pressure resulted in horizontal and vertical wind shear due to cyclonic circulation. The wind direction was apparently different across the warm front. In addition, the southeasterly flow (below 4 km) played an important role in generating new convective cells behind the prevailing convective cell. Each isolated southern convective cell (meso-β-scale) moved along the line ahead of the cold front within the prefrontal warm sector. These convective cells developed when a strong southwesterly low-level jet (LLJ) intensified and moisture was deeply advected into the sloping frontal zone. A high equivalent potential temperature region transported warm moist air in a strong southwesterly flow, where the convectively unstable air led to updraft and downdraft with a strong reflectivity core.

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Airborne Radar Observations of a Warm Front during FASTEX

Monthly Weather Review ◽

10.1175/1520-0493(2001)129<0254:arooaw>2.0.co;2 ◽

2001 ◽

Vol 129 (2) ◽

pp. 254-274 ◽

Cited By ~ 14

Author(s):

Roger M. Wakimoto ◽

Brian L. Bosart

Keyword(s):

Airborne Radar ◽

Radar Observations ◽

Warm Front

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Systematic assessment of the diabatic processes that modify low-level potential vorticity in extratropical cyclones

10.5194/wcd-2021-37 ◽

2021 ◽

Author(s):

Roman Attinger ◽

Elisa Spreitzer ◽

Maxi Boettcher ◽

Heini Wernli ◽

Hanna Joos

Keyword(s):

Temperature Difference ◽

Cold Front ◽

Warm Season ◽

Cold Season ◽

Radiative Heating ◽

Extratropical Cyclones ◽

Sea Temperature ◽

Long Wave ◽

Warm Front ◽

Diabatic Processes

Abstract. Diabatic processes significantly affect the development and structure of extratropical cyclones. Previous studies quantified the dynamical relevance of selected diabatic processes by studying their influence on potential vorticity (PV) in individual cyclones. However, a more general assessment of the relevance of all PV-modifying processes in a larger ensemble of cyclones is currently missing. Based on a series of twelve 35-day model simulations using the Integrated Forecasting System (IFS) of the European Centre for Medium-range Weather Forecasts (ECMWF), this study systematically quantifies the relevance of individual diabatic processes for the dynamics of 288 rapidly intensifying extratropical cyclones. To this end, PV tendencies associated with each parametrized process in the model are accumulated along 15 h backward trajectories. The investigation focuses on regions of high PV (≥ 1 PVU) along the cold front, warm front, and in the cyclone center, as well as of negative PV (≤ −0.1 PVU) along the cold and warm front in the lower troposphere. On average, the primary processes that modify PV during the 24 h period of most rapid cyclone intensification remain temporally consistent for all anomalies considered. However, a pronounced case-to-case variability is found when comparing the dominant processes across individual cyclones. Along the cold front, PV is primarily generated by condensation in half of the investigated cyclones. For the remaining cyclones, convection or long-wave radiative cooling become the dominant process depending on environmental conditions. Results are similar for both seasons, with a reduced role of convection for the generation of PV along the cold front in the warm season. Negative PV west of the cold front is produced by turbulent exchange of momentum and temperature as well as long-wave radiative heating. The relevance of long-wave radiative heating is reduced during summer. The positive PV anomaly at the warm front is predominantly generated by condensation in the cold season, whereas turbulent mixing becomes the prevalent process during the warm season. Convection only plays a minor role for the generation of PV at the warm front. Negative PV along the warm front is produced by long-wave radiative heating, turbulent temperature tendencies, or melting of snow in the cold season. Turbulent temperature tendencies become the dominant process decreasing PV at the warm front in the warm season, together with melting of snow and turbulent exchange of momentum. The positive PV anomaly in the cyclone center is primarily produced by condensation, with only few cyclones where PV production is mainly associated with turbulent mixing or convection. A composite analysis further reveals that PV anomalies generated by convection require a negative air-sea temperature difference in the warm sector of the cyclone, which promotes a heat flux directed into the atmosphere and destabilizes the boundary layer. These cyclones primarily occur over warm ocean currents in the cold season. On the other hand, cyclones that occur in a significantly colder environment are often associated with a positive air-sea temperature difference in the warm sector, leading to PV generation by long-wave radiative cooling. Finally, long-wave radiative heating due to a negative air-sea temperature difference in the cold sector can produce negative PV along the cold and warm front. The general agreement between accumulated PV tendencies and the net PV change along trajectories is good. Therefore, the approach used in this study yields valuable insight regarding the specific physical processes that modify low-level PV in rapidly deepening extratropical cyclones.

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