Location of Stromboli volcano July 2019 paroxysm event based on long-range infrasound detections in several IMS stations

Stromboli is one of the most active volcanoes on Earth with a continuous explosive activity and persistent degassing since at least 3-7 AD (Rossi et al., 2000). Being an open conduit volcano, its spectacular basaltic explosions interspersed by lava fountains occurring every &#8776;10 minutes (Ripepe et al., 2002) make it probably the world's best-know and best-monitored volcano.On 3rd July 2019 at the 14:45:43 UTC a paroxysmal explosion occurred with an ash column that rose almost 5 km above the volcano. This very strong explosive event was detected in several IMS infrasound stations, including IS42, located in the Azores islands in the middle of the North-Atlantic, at a distance of about 3,700 km.We present the long-range infrasound detections that allowed us to locate the source based only in infrasound with an estimated error of less than 55 km from the ground truth event.Keywords: Stromboli volcano, paroxysm, infrasound, IMS, IS42

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Lagrangian formation pathways of moist anomalies in the trade-wind region during the dry season: two case studies from EUREC4A

10.5194/wcd-2021-42 ◽

2021 ◽

Author(s):

Leonie Villiger ◽

Heini Wernli ◽

Maxi Boettcher ◽

Martin Hagen ◽

Franziska Aemisegger

Keyword(s):

Long Range ◽

North Atlantic ◽

Large Scale ◽

Cold Front ◽

Trade Wind ◽

Long Range Transport ◽

The North ◽

Range Transport ◽

The North Atlantic ◽

The Tropics

Abstract. Shallow clouds in the trade-wind region over the North Atlantic contribute substantially to the global radiative budget. In the vicinity of the Caribbean island Barbados, they appear in different mesoscale organisation patterns with distinct net cloud radiative effects (CRE). Cloud formation processes in this region are typically controlled by the prevailing large-scale subsidence. However, occasionally weather systems from remote origin cause significant disturbances. This study investigates the complex cloud-circulation interactions during the field campaign EUREC4A (Elucidate the Couplings Between Clouds, Convection and Circulation) from 16 January to 20 February 2020, using a combination of Eulerian and Lagrangian diagnostics. Based on observations and ERA5 reanalyses, we identify the relevant processes and characterise the formation pathways of two moist anomalies above the Barbados Cloud Observatory (BCO), one in the lower (~1000–650 hPa) and one in the middle troposphere (~650–300 hPa). These moist anomalies are associated with strongly negative CRE values and with contrasting long-range transport processes from the extratropics and the tropics, respectively. The low-level moist anomaly is characterised by an unusually thick cloud layer, high precipitation totals and a strongly negative CRE. Its formation is connected to an “extratropical dry intrusion” (EDI) that interacts with a trailing cold front. A quasi-climatological (2010–2020) analysis reveals that EDIs lead to different conditions at the BCO depending on how they interact with the associated cold front. Based on this climatology, we discuss the relevance of the strong large-scale forcing by EDIs for the low-cloud patterns near the BCO and the related CRE. The second case study about the mid-tropospheric moist anomaly is associated with an extended and persistent mixed-phase shelf cloud and the lowest daily CRE value observed during the campaign. Its formation is linked to “tropical mid-level detrainment” (TMD), which refers to detrainment from tropical deep convection near the melting layer. The quasi-climatological analysis shows that TMDs consistently lead to mid-tropospheric moist anomalies over the BCO and that the detrainment height controls the magnitude of the anomaly. However, no systematic relationship was found between the amplitude of this mid-tropospheric moist anomaly and the CRE at the BCO. Overall, this study reveals the important impact of the long-range transport, driven by dynamical processes either in the extratropics or the tropics, on the variability of the vertical structure of moisture and clouds, and on the resulting CRE in the North Atlantic winter trades.

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The Evaluation and Use of the Dectra Navigation System

Journal of Navigation ◽

10.1017/s0373463300017768 ◽

1958 ◽

Vol 11 (4) ◽

pp. 377-384

Author(s):

E. W. Hare

Keyword(s):

Long Range ◽

North Atlantic ◽

Navigation System ◽

Radio Navigation ◽

The North ◽

Radio Navigation System ◽

Accurate Position ◽

The North Atlantic

Dectra is a long-range radio navigation system designed to give accurate position fixing coverage over specific areas, and in particular over long trans-oceanic crossings. The position of an aircraft or ship equipped with a Dectra receiver is continuously available in the form of dial indications relating to coordinates of a Dectra lattice, and in addition this information can be presented pictorially on a normal Decca flight log. The system is at present functioning over the North Atlantic, and flight trials have been in progress since May 1957. This paper discusses the experience gained and the results obtained in the trials.

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Incomplete recovery to enhance economic growth losses from US hurricanes under global warming

10.21203/rs.3.rs-654258/v1 ◽

2021 ◽

Author(s):

Christian Otto ◽

Kilian Kuhla ◽

Tobias Geiger ◽

Jacob Schewe ◽

Katja Frieler

Keyword(s):

Economic Growth ◽

Global Warming ◽

North Atlantic ◽

Insurance Coverage ◽

The United States ◽

Response Dynamics ◽

Frequency Increase ◽

Hurricane Impacts ◽

The North ◽

Event Based

Abstract Ongoing global warming is likely to increase the return frequency of very intense hurricanes in the North Atlantic. Here, we analyse how this frequency increase may impact on economic growth. To this end, we introduce an event-based macroeconomic growth model that allows us to assess how growth depends on the heterogeneity of hurricane impacts, by temporally resolving the economic response dynamics to individual hurricanes making landfall. We calibrate the model to hurricane impacts in the United States and find that economic growth losses scale super-linearly with the heterogeneity of hurricane impacts. We explain this by a disproportional increase of indirect losses with event severity which can lead to an incomplete recovery of the economy between consecutive intense landfall events. Based on two different methods to estimate the frequency increase of intense hurricanes, we estimate annual growth losses to increase by moderate 7% up to 146% in a 2°C world compared to the period 1980-2014. Our modelling suggests that higher insurance coverage may be a viable means to mitigate this climate change-induced increase in growth losses.

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A stratospheric prognostic ozone for seamless Earth System Models: performance, impacts and future

10.5194/acp-2020-1261 ◽

2021 ◽

Author(s):

Beatriz M. Monge-Sanz ◽

Alessio Bozzo ◽

Nicholas Byrne ◽

Martyn P. Chipperfield ◽

Michail Diamantakis ◽

...

Keyword(s):

Long Range ◽

North Atlantic ◽

Signal To Noise Ratio ◽

Stratospheric Ozone ◽

Polar Vortex ◽

Atlantic Sector ◽

The North ◽

Medium Range ◽

Antarctic Polar Vortex ◽

The Impact

Abstract. We have implemented a new stratospheric ozone model in the European Centre for Medium-Range Weather Forecasts (ECMWF) system, and tested its performance for different timescales, to assess the impact of stratospheric ozone on meteorological fields. We have used the new ozone model to provide prognostic ozone in medium-range and long-range experiments, showing the feasibility of this ozone scheme for a seamless NWP modelling approach. We find that the stratospheric ozone distribution provided by the new scheme in ECMWF forecast experiments is in very good agreement with observations, even for unusual meteorological conditions such as Arctic stratospheric sudden warmings (SSWs) and Antarctic polar vortex events like the vortex split of year 2002. To assess the impact it has on meteorological variables, we have performed experiments in which the prognostic ozone is interactive with radiation. The new scheme provides a realistic ozone field able to improve the description of the stratosphere in the ECMWF system, we find clear reductions of biases in the stratospheric forecast temperature. The seasonality of the Southern Hemisphere polar vortex is also significantly improved when using the new ozone model. In medium-range simulations we also find improvements in high latitude tropospheric winds during the SSW event considered in this study. In long-range simulations the use of the new ozone model leads to an increase in the winter North Atlantic Oscillation (NAO) index correlation, and an increase in the signal to noise ratio over the North Atlantic sector. In our study we show that by improving the description of the stratospheric ozone in the ECMWF system, the stratosphere-tropospheric coupling improves. This highlights the potential benefits of this new ozone model to exploit stratospheric sources of predictability and improve weather predictions over Europe on a range of time scales.

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Navigational Aspects of Turboprop Operation on the North Atlantic

Journal of Navigation ◽

10.1017/s0373463300016325 ◽

1957 ◽

Vol 10 (1) ◽

pp. 31-49

Author(s):

J. E. D. Williams

Keyword(s):

Sixteenth Century ◽

Long Range ◽

North Atlantic ◽

Fuel Load ◽

The North ◽

The Status ◽

The North Atlantic ◽

Aircraft Type

If navigation were confined to the function of keeping a craft on a desired track, and estimating its progress periodically, then a long-range turboprop would present no features of navigational interest. Navigation, however, is supposed to encompass a wider field than this. In a famous sixteenth-century definition, ‘Navigation demonstrateth how, by the shortest good way, by the aptest direction, and in the shortest time, a sufficient ship between any two places may be conducted’. The economic realities of modern airliner operation give a new emphasis to those phrases ‘By the shortest good way, by the aptest direction, and in the shortest time’. A Britannia 310, for example, which will be the first, probably the cheapest, and possibly the smallest, long-range turbineengined airliner, costs about £1 million and is capable of producing a gross revenue of £1000 per hour. The sum of payload and fuel load is limited in most long-range cases by maximum take-off weight, and the fuel for one hour of flight is equivalent in weight to about 2 5 passengers and their baggage. It is not surprising in the circumstances that quite minor refinements of navigational technique are worth tens of thousands of pounds per aircraft per year, while major improvements can alter the status of an aircraft type as an instrument of transport. Such aircraft should be considered as acutely sensitive instruments to be operated precisely according to scientifically designed techniques.

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