Abnormal Gravity Wave Activity in the Stratosphere Prior to the 2016 Kumamoto Earthquakes

2019 ◽  
Vol 124 (2) ◽  
pp. 1410-1425 ◽  
Author(s):  
Shih‐Sian Yang ◽  
Tomokazu Asano ◽  
Masashi Hayakawa
Keyword(s):  
Gravity Wave ◽  
Wave Activity ◽  
The 2016 Kumamoto Earthquakes ◽  
2016 Kumamoto Earthquakes

scholarly journals Influence of the cloud-level neutral layer on the vertical propagation of topographically generated gravity waves on Venus

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Takeru Yamada ◽  
Takeshi Imamura ◽  
Tetsuya Fukuhara ◽  
Makoto Taguchi
Keyword(s):  
Layer Thickness ◽  
Gravity Wave ◽  
Local Time ◽  
Gravity Waves ◽  
Analytical Approach ◽  
Wave Activity ◽  
Neutral Layer ◽  
Low Latitudes ◽  
Vertical Propagation ◽  
The Waves

AbstractThe reason for stationary gravity waves at Venus’ cloud top to appear mostly at low latitudes in the afternoon is not understood. Since a neutral layer exists in the lower part of the cloud layer, the waves should be affected by the neutral layer before reaching the cloud top. To what extent gravity waves can propagate vertically through the neutral layer has been unclear. To examine the possibility that the variation of the neutral layer thickness is responsible for the dependence of the gravity wave activity on the latitude and the local time, we investigated the sensitivity of the vertical propagation of gravity waves on the neutral layer thickness using a numerical model. The results showed that stationary gravity waves with zonal wavelengths longer than 1000 km can propagate to the cloud-top level without notable attenuation in the neutral layer with realistic thicknesses of 5–15 km. This suggests that the observed latitudinal and local time variation of the gravity wave activity should be attributed to processes below the cloud. An analytical approach also showed that gravity waves with horizontal wavelengths shorter than tens of kilometers would be strongly attenuated in the neutral layer; such waves should originate in the altitude region above the neutral layer.

Long-Term Prevalence of Disaster-Related Deep Vein Thrombosis in Minamiaso Village After the 2016 Kumamoto Earthquakes: A Prospective Cross-Sectional Analysis

2021 ◽  
pp. 1-8
Author(s):  
Hidenori Onishi ◽  
Osamu Yamamura ◽  
Hiromasa Tsubouchi ◽  
Takeshi Hirobe ◽  
Ikuko Kosugi ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Recovery Phase ◽  
Cross Sectional ◽  
Portable Ultrasound ◽  
Entire Cohort ◽  
Vein Thrombosis ◽  
The 2016 Kumamoto Earthquakes ◽  
Long Time ◽  
Deep Vein ◽  
2016 Kumamoto Earthquakes

Abstract Objective: This study aimed to examine the prevalence of deep vein thrombosis (DVT) among evacuees in Minamiaso, a village which was temporarily isolated after the earthquakes, from the acute to recovery phase after the 2016 Kumamoto Earthquakes (GLIDE no: EQ-2016-000033-JPN). Methods: This prospective study, which was approved by Fukui University Medical Research Ethics Committee (approval no. 20160024 and 20160089), enrolled 181 evacuees (73.9 ± 11.6 y) who participated in a series of 3 DVT screenings using portable ultrasound machines conducted over 19 mo. All participants completed a questionnaire before the screenings, and none of the participants attended all 3 screenings. Data analysis was performed using EZR version 1.41. Results: The DVT prevalence was 14.3% (79.4 ± 8.2 y) at first screening of evacuees staying in shelters and 18.5% (71.5 ± 13.1 y) and 12.2% (72.8 ± 10.9 y) in second and third screenings of evacuees staying in temporary housing, respectively. Multivariate analysis revealed age ≥75 y and alcohol consumption as independent risk factors in the entire cohort and in patients aged ≤74 y, respectively. Conclusions: A high DVT prevalence over a long time period of 19 mo was observed where survivors were temporarily isolated after the disaster.

scholarly journals 11 Years of Rayleigh Lidar Observations of Gravity Wave Activity Above the Southern Tip of South America

2019 ◽  
Vol 124 (2) ◽  
pp. 451-467 ◽  
Author(s):  
P. Llamedo ◽  
J. Salvador ◽  
A. Torre ◽  
J. Quiroga ◽  
P. Alexander ◽  
...  
Keyword(s):  
South America ◽  
Gravity Wave ◽  
Wave Activity ◽  
Rayleigh Lidar ◽  
Lidar Observations

scholarly journals Rayleigh/Raman lidar observations of gravity wave activity from 15 to 70 km altitude over Syowa (69°S, 40°E), the Antarctic

2017 ◽  
Vol 122 (15) ◽  
pp. 7869-7880 ◽  
Author(s):  
Masaru Kogure ◽  
Takuji Nakamura ◽  
Mitsumu K. Ejiri ◽  
Takanori Nishiyama ◽  
Yoshihiro Tomikawa ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Wave Activity ◽  
Raman Lidar ◽  
The Antarctic ◽  
Lidar Observations

scholarly journals Enhanced gravity-wave activity and interhemispheric coupling during the MaCWAVE/MIDAS northern summer program 2002

2006 ◽  
Vol 24 (4) ◽  
pp. 1175-1188 ◽  
Author(s):  
E. Becker ◽  
D. C. Fritts
Keyword(s):  
Gravity Wave ◽  
Rossby Wave ◽  
Lower Thermosphere ◽  
Wave Activity ◽  
Lower Atmosphere ◽  
Summer Program ◽  
Latent Heating ◽  
Austral Winter ◽  
Northern Summer ◽  
Mesosphere And Lower Thermosphere

Abstract. We present new sensitivity experiments that link observed anomalies of the mesosphere and lower thermosphere at high latitudes during the MaCWAVE/MIDAS summer program 2002 to enhanced planetary Rossby-wave activity in the austral winter troposphere. We employ the same general concept of a GCM having simplified representations of radiative and latent heating as in a previous study by Becker et al. (2004). In the present version, however, the model includes no gravity wave (GW) parameterization. Instead we employ a high vertical and a moderate horizontal resolution in order to describe GW effects explicitly. This is supported by advanced, nonlinear momentum diffusion schemes that allow for a self-consistent generation of inertia and mid-frequency GWs in the lower atmosphere, their vertical propagation into the mesosphere and lower thermosphere, and their subsequent dissipation which is induced by prescribed horizontal and vertical mixing lengths as functions of height. The main anomalies in northern summer 2002 consist of higher temperatures than usual above 82 km, an anomalous eastward mean zonal wind between 70 and 90 km, an altered meridional flow, enhanced turbulent dissipation below 80 km, and enhanced temperature variations associated with GWs. These signals are all reasonably described by differences between two long-integration perpetual model runs, one with normal July conditions, and another run with modified latent heating in the tropics and Southern Hemisphere to mimic conditions that correspond to the unusual austral winter 2002. The model response to the enhanced winter hemisphere Rossby-wave activity has resulted in both an interhemispheric coupling through a downward shift of the GW-driven branch of the residual circulation and an increased GW activity at high summer latitudes. Thus a quantitative explanation of the dynamical state of the northern mesosphere and lower thermosphere during June-August 2002 requires an enhanced Lorenz energy cycle and correspondingly enhanced GW sources in the troposphere, which in the model show up in both hemispheres.

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