Epicrania Fugax with a Novel Sign: Pain Paroxysms with Parallel Forward or Backward Trajectories

Abstract. Heterogeneous ice formation induced by volcanic ash from the Eyjafjallajökull volcano eruption in April 2010 is investigated based on the combination of a cirrus cloud observed with a backscatter lidar over Jülich (Western Germany) and model simulations along backward trajectories. The microphysical properties of the cirrus cloud could only be represented by the microphysical model under the assumption of an enhanced number of efficient ice nuclei originating from the volcanic eruption. The ice nuclei (IN) concentration determined by lidar measurements directly before and after cirrus cloud occurrence implies a value of around 0.1 cm−3 (in comparison clean IN conditions: 0.01 cm−3). This leads to a cirrus cloud with rather small ice crystals having a mean radius of 12 μm and a modification of the ice particle number (0.08 cm−3 instead of 3 × 10−4 cm−3 under clean IN conditions). The effectiveness of ice nuclei was estimated by the use of the microphysical model and the backward trajectories based on ECMWF data, establishing a freezing threshold of around 105% relative humidity with respect to ice in a temperature range from −45 to −55 °C. Only with these highly efficient ice nuclei was it possible for the cirrus cloud to be formed in a slightly supersaturated environment.

Download Full-text

Transport timescales and tracer properties in the extratropical UTLS

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-12953-2010 ◽

2010 ◽

Vol 10 (5) ◽

pp. 12953-12991 ◽

Cited By ~ 1

Author(s):

P. Hoor ◽

H. Wernli ◽

M. I. Hegglin

Keyword(s):

Transit Time ◽

Chemical Structure ◽

Comprehensive Evaluation ◽

Mixing Ratio ◽

Backward Trajectories ◽

Tropical Tropopause ◽

Northern Winter ◽

Cold Point ◽

The Tropics

Abstract. A comprehensive evaluation of seasonal backward trajectories initialized in the Northern Hemisphere lowermost stratosphere (LMS) has been performed to investigate the origin of air parcels and the main mechanisms determining characteristic structures in H2O and CO within the LMS. In particular we explain the fundamental role of the transit time since last tropopause crossing (tTST) for the chemical structure of the LMS as well as the feature of the extra-tropical tropopause transition layer (ExTL) as identified from CO profiles. The distribution of H2O in the background LMS above Θ=320 K and 340 K in northern winter and summer, respectively, is found to be governed mainly by the saturation mixing ratio, which in turn is determined by the Lagrangian Cold Point (LCP) encountered by each trajectory. Most of the backward trajectories from this region in the LMS experienced their LCP in the tropics and sub-tropics. The transit time since crossing the tropopause from the troposphere to the stratosphere (tTST) is independent of the H2O value of the air parcel. TST often occurs 20 days after trajectories have encountered their LCP. CO, on the other hand, depends strongly on tTST due to its finite lifetime. The ExTL as identified from CO measurements is then explained as a layer of air just above the tropopause, which on average encountered TST fairly recently.

Download Full-text

A Three-Dimensional Trajectory Model with Advection Correction for Tropical Cyclones: Algorithm Description and Tests for Accuracy

Monthly Weather Review ◽

10.1175/mwr-d-18-0434.1 ◽

2019 ◽

Vol 147 (9) ◽

pp. 3145-3167 ◽

Cited By ~ 1

Author(s):

William Miller ◽

Da-Lin Zhang

Keyword(s):

Doppler Radar ◽

Three Dimensional ◽

Linear Interpolation ◽

Model Output ◽

Advective Flow ◽

Computational Stability ◽

Time Step ◽

Backward Trajectories ◽

Position Errors ◽

Advective Flows

Abstract When computing trajectories from model output, gridded winds are often temporally interpolated to a time step shorter than model output intervals to satisfy computational stability constraints. This study investigates whether trajectory accuracy may be improved for tropical cyclone (TC) applications by interpolating the model winds using advection correction (AC) instead of the traditional linear interpolation in time (LI) method. Originally developed for Doppler radar processing, AC algorithms interpolate data in a reference frame that moves with the pattern translation, or advective flow velocity. A previously developed trajectory AC implementation is modified here by extending it to three-dimensional (3D) flows, and the advective flows are defined in cylindrical rather than Cartesian coordinates. This AC algorithm is tested on two model-simulated TC cases, Hurricanes Joaquin (2015) and Wilma (2005). Several variations of the AC algorithm are compared to LI on a sample of 10 201 backward trajectories computed from the modeled 5-min output data, using reference trajectories computed from 1-min output to quantify position errors. Results show that AC of 3D wind vectors using advective flows defined as local gridpoint averages improves the accuracy of most trajectories, with more substantial improvements being found in the inner eyewall where the horizontal flows are dominated by rotating cyclonic wind perturbations. Furthermore, AC eliminates oscillations in vertical velocity along LI backward trajectories run through deep convective updrafts, leading to a ~2.5-km correction in parcel height after 20 min of integration.

Download Full-text

Paroxysmal headache with extracephalic irradiation: Proposal for a new variant of epicrania fugax in a series of five patients

Cephalalgia ◽

10.1177/0333102420920646 ◽

2020 ◽

Vol 40 (9) ◽

pp. 959-965 ◽

Cited By ~ 2

Author(s):

María Gutiérrez-Sánchez ◽

David García-Azorín ◽

Álvaro Gutiérrez-Viedma ◽

Nuria González-García ◽

Alejandro Horga ◽

...

Keyword(s):

Standard Deviation ◽

Age At Onset ◽

Spontaneous Remission ◽

Complete Response ◽

Descriptive Study ◽

Nummular Headache ◽

New Variant ◽

Epicrania Fugax ◽

The Face ◽

The Mean

Background Epicrania fugax consists of brief paroxysms of pain, which radiate in a line or in zigzag trajectory across the surface of the scalp or the face. Methods A prospective, descriptive study was performed in five patients presenting with an epicrania fugax-type pain with extracephalic irradiation. Results All patients were women, and the mean age at onset was 59.8 (standard deviation, 10.9). They had unilateral paroxysms of electrical pain starting at a particular point in the head (parietal, n = 3; vertex, n = 1; frontal, n = 1) and rapidly radiating downwards in a lineal trajectory to reach extracephalic regions (ipsilateral limbs, n = 2; shoulder, n = 2; low neck, n = 1) in 1–3 seconds. Pain intensity was moderate or severe. Three patients had nummular headache at the point where the paroxysms originated. One patient had spontaneous remission, and four patients achieved complete or almost complete response with therapy (onabotulinumtoxinA, n = 2; indomethacin, n = 1; amitriptyline, n = 1; lamotrigine, n = 1). Conclusion The spectrum of epicrania fugax may include paroxysms with extracephalic irradiation. The propagation of pain beyond the head and the face supports the involvement of central mechanisms in the pathophysiology of this entity.

Download Full-text

Detection of saharan mineral dust aerosol transport over brazilian northeast through a depolarization lidar

EPJ Web of Conferences ◽

10.1051/epjconf/201817605036 ◽

2018 ◽

Vol 176 ◽

pp. 05036 ◽

Cited By ~ 2

Author(s):

Anderson G. Guedes ◽

Eduardo Landulfo ◽

Elena Montilla-Rosero ◽

Fábio J.S. Lopes ◽

Judith J. Hoelzemann ◽

...

Keyword(s):

Satellite Data ◽

Mineral Dust ◽

Dust Aerosol ◽

Saharan Dust ◽

Depolarization Ratio ◽

Aerosol Transport ◽

Half Wave Plate ◽

Backward Trajectories ◽

Half Wave ◽

Brazilian Northeast

In this study we present results of linear volume depolarization ratio profiles obtained by a depolarization lidar in operation in Natal, Brazil. The DUSTER system has 4 channels, namely: 1064, 532 s/p and 355 nm. This system is calibrated with a half-wave plate using the Δ90° methodology. The data obtained from this system is correlated with AERONET sunphotometer data, and, when available, CALIPSO satellite data. In addition a trajectory model (HYSPLIT) is used to calculate backward trajectories to assess the origin of the dust polluted air parcels. The objective is to create a transport database of Saharan dust.

Download Full-text

On the Connection between Atmospheric Moisture Transport and Dry Conditions in Rainfall Climatological Zones of the Niger River Basin

Water ◽

10.3390/w11030622 ◽

2019 ◽

Vol 11 (3) ◽

pp. 622 ◽

Cited By ~ 1

Author(s):

Rogert Sorí ◽

Raquel Nieto ◽

Anita Drumond ◽

Milica Stojanovic ◽

Luis Gimeno

Keyword(s):

Atlantic Ocean ◽

River Basin ◽

South Atlantic ◽

South Atlantic Ocean ◽

Moisture Uptake ◽

Backward Trajectories ◽

Standardised Precipitation Index ◽

Average Precipitation ◽

Dry Conditions ◽

Niger River

The hydroclimatology of the Niger River basin, located in West Africa, is very complex. It has been widely studied because of its importance to the socioeconomic activities of the countries that share its natural resources. In this study, to better understand the causes and mechanisms that modulate the rainfall over the Niger River basin, we identified the most relevant moisture sources for precipitation within the basin. The Lagrangian model FLEXPART was utilised to track backward trajectories of air parcels initially losing humidity over climatological rainfall zones of the basin. Along 10-day backward trajectories, we computed the budget of the difference between evaporation and precipitation (E − P) from 1000 to 0.1 hPa, permitting the identification of those regions where moisture uptake ((E − P) > 0) prevail. The study was conducted for the period 1980–2017. Monthly maps of ((E − P) > 0 were developed to illustrate the regions from where moisture is transported, contributing to precipitation in the Niger River basin. The spatial variability of the sources matches the precipitation variability over the basin restricted to surrounding areas of the Niger River basin during months with low average precipitation and widely spreading over the continent and the Atlantic Ocean in months with high average precipitation. During climatological dry months (e.g., December, January and February) the continental sources of West and Northeast Africa and the climatological rainfall zones themselves provide most of the moisture for precipitation. However, during the rainy season, the moisture supplies from oceanic sources increase, becoming greater than the contribution from land-based sources during August (the rainiest month). Dry conditions were identified for each climatological rainfall zone using the Standardised Precipitation Index. Similar to many previous studies, we found that the 1980s were highlighted by dry conditions. Local recycling and particularly moisture uptake from the tropical South Atlantic Ocean seem to be highly related to dry and wet conditions in the basin. A reduction on the moisture uptake from surrounding continental sources and the tropical South Atlantic Ocean is almost persistent during extremely dry conditions. Ascending movements are restricted to the lower troposphere during extremely dry conditions and oscillate latitudinally as well as precipitation.

Download Full-text

Seasonal characteristics of trace gas transport into the extratropical upper troposphere and lower stratosphere

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-7073-2019 ◽

2019 ◽

Vol 19 (10) ◽

pp. 7073-7103 ◽

Cited By ~ 1

Author(s):

Yoichi Inai ◽

Ryo Fujita ◽

Toshinobu Machida ◽

Hidekazu Matsueda ◽

Yousuke Sawa ◽

...

Keyword(s):

Lower Stratosphere ◽

Trace Gases ◽

Source Region ◽

Lower Troposphere ◽

Trace Gas ◽

Air Masses ◽

Backward Trajectories ◽

Upper Troposphere ◽

Passive Behavior ◽

Seasonal Characteristics

Abstract. To investigate the seasonal characteristics of trace gas distributions in the extratropical upper troposphere and lower stratosphere (ExUTLS) as well as stratosphere–troposphere exchange processes, origin fractions of air masses originating in the stratosphere, tropical troposphere, midlatitude lower troposphere (LT), and high-latitude LT in the ExUTLS are estimated using 10-year backward trajectories calculated with European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim data as the meteorological input. Time series of trace gases obtained from ground-based and airborne observations are incorporated into the trajectories, thus reconstructing spatiotemporal distributions of trace gases in the ExUTLS. The reconstructed tracer distributions are analyzed with the origin fractions and the stratospheric age of air (AoA) estimated using the backward trajectories. The reconstructed distributions of SF6 and CO2 in the ExUTLS are linearly correlated with those of AoA because of their chemically passive behavior and quasi-stable increasing trends in the troposphere. Distributions of CH4, N2O, and CO are controlled primarily by chemical decay along the transport path from the source region via the stratosphere and subsequent mixing of such stratospheric air masses with tropospheric air masses in the ExUTLS.

Download Full-text

Lidar derived properties of air-masses advected from Ukraine, Sahara and Carpathian mountains to Warsaw, Poland on 9 - 11 August 2015

EPJ Web of Conferences ◽

10.1051/epjconf/201817605003 ◽

2018 ◽

Vol 176 ◽

pp. 05003

Author(s):

Lucja Janicka ◽

Dominika Szczepanik ◽

Karolina Borek ◽

Birgit Heese ◽

Iwona S. Stachlewska

Keyword(s):

Aerosol Particles ◽

Carpathian Mountains ◽

Air Masses ◽

Backward Trajectories ◽

Derived Properties ◽

Different Sources ◽

Different Origin

The aerosol layers of different origin, suspended in the atmosphere on 9-11 August 2015 were observed with the PollyXT-UW lidar in Warsaw, Poland. The HYSPLIT ensemble backward trajectories indicate that the observed air-masses attribute to a few different sources, among others, possible transport paths from Ukraine, Slovakia, and Africa. In this paper, we attempt to analyse and discuss the properties of aerosol particles of different origin that were suspended over Warsaw during this event.

Download Full-text