Role of gravity waves in the spatial and temporal variability of stratospheric temperature measured by COSMIC/FORMOSAT-3 and Rayleigh lidar observations

2010 ◽  
Vol 115 (D19) ◽  
Author(s):  
Adrian J. McDonald ◽  
Bo Tan ◽  
Xinzhao Chu
Keyword(s):  
Gravity Waves ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Stratospheric Temperature ◽  
Rayleigh Lidar ◽  
Lidar Observations

scholarly journals Night-to-night changes in the characteristics of gravity waves at stratospheric and lower-mesospheric heights

1998 ◽  
Vol 16 (2) ◽  
pp. 229-237 ◽  
Author(s):  
A. J. McDonald ◽  
L. Thomas ◽  
D. P. Wareing
Keyword(s):  
Gravity Waves ◽  
Wave Activity ◽  
Mountain Waves ◽  
Long Period ◽  
Convective Instabilities ◽  
Radar Systems ◽  
Mst Radar ◽  
Vertical Propagation ◽  
Rayleigh Lidar ◽  
Lidar Observations

Abstract. Observations made with the co-located Rayleigh lidar and MST radar systems at Aberystwyth (52.4°N, 4.1°W) in Wales and radiosondes from Valentia (51.9°N, 10.2°W) in Eire are used to investigate the changes in the vertical propagation of gravity waves during periods of 4 days in June 1995 and February 1993. In each month, the lidar observations show that the wave activity in the upper stratosphere and lower mesosphere changes between two pairs of days. The radar and radiosonde measurements indicate that mountain waves make no contribution to the changes in intensity. Instead, the changes seem to arise largely from the presence or absence of long-period waves with vertical wavelengths near 8 and 10 km in June and February, respectively. The influence of such waves on the vertical wavenumber spectra is examined and related to the evidence for convective instabilities provided by the temperature profiles.Key words. Rayleigh lidar · MST radar systems · Radiosondes · Gravity waves

The role of storm movement in controlling flash flood response: an analysis of the 28 September 2012 extreme event in Murcia, southeastern Spain

2021 ◽  
Author(s):  
A. Amengual ◽  
M. Borga ◽  
G. Ravazzani ◽  
S. Crema
Keyword(s):  
Temporal Variability ◽  
Flash Flood ◽  
Spatial And Temporal Variability ◽  
Hydrological Response ◽  
Catchment Scale ◽  
Flash Flooding ◽  
Southeastern Spain ◽  
Flood Response

AbstractFlash flooding is strongly modulated by the spatial and temporal variability in heavy precipitation. Storm motion prompts a continuous change of rainfall space-time variability that interacts with the drainage river system, thus influencing the flood response. The impact of storm motion on hydrological response is assessed for the 28 September 2012 flash flood over the semi-arid and medium-sized Guadalentín catchment in Murcia, southeastern Spain. The influence of storm kinematics on flood response is examined through the concept of ‘catchment-scale storm velocity’. This variable quantifies the interaction between the storm system motion and the river drainage network, assessing its influence on the hydrograph peak. By comparing two hydrological simulations forced by rainfall scenarios of distinct spatial and temporal variability, the role of storm system movement on the flood response is effectively isolated. This case study is the first to: (i) show through the catchment-scale storm velocity how storm motion may strongly affect flood peak and timing; and (ii) assess the influence of storm kinematics on hydrological response at different basin scales. In the end, this extreme flash flooding provides a valuable case study of how the interaction between storm motion and drainage properties modulate hydrological response.

scholarly journals Ice front change of marine-terminating outlet glaciers in northwest and southeast Greenland during the 21st century

2018 ◽  
Vol 64 (246) ◽  
pp. 523-535 ◽  
Author(s):  
CHARLIE BUNCE ◽  
J. RACHEL CARR ◽  
PETER W. NIENOW ◽  
NEIL ROSS ◽  
REBECCA KILLICK
Keyword(s):  
Temporal Variability ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Spatial And Temporal Variability ◽  
Spatial And Temporal Patterns ◽  
Negative Mass ◽  
Position Change ◽  
Specific Factors ◽  
Enhanced Surface

ABSTRACTThe increasingly negative mass balance of the Greenland ice sheet (GrIS) over the last ~25 years has been associated with enhanced surface melt and increased ice loss from marine-terminating outlet glaciers. Accelerated retreat during 2000–2010 was concentrated in the southeast and northwest sectors of the ice sheet; however, there was considerable spatial and temporal variability in the timing and magnitude of retreat both within and between these regions. This behaviour has yet to be quantified and compared for all glaciers in both regions. Furthermore, it is unclear whether retreat has continued after 2010 in the northwest, and whether the documented slowdown in the southeast post-2005 has been sustained. Here, we compare spatial and temporal patterns of frontal change in the northwest and southeast GrIS, for the period 2000–2015. Our results show near-ubiquitous retreat of outlet glaciers across both regions for the study period; however, the timing and magnitude of inter-annual frontal position change is largely asynchronous. We also find that since 2010, there is continued terminus retreat in the northwest, which contrasts with considerable inter-annual variability in the southeast. Analysis of the role of glacier-specific factors demonstrates that fjord and bed geometry are important controls on the timing and magnitude of glacier retreat.

Spatial and temporal variability, triggers and drivers of seismically detected rockfalls in the Reintal catchment, German Alps 

2021 ◽  
Author(s):  
Anne Schöpa ◽  
Jens Turowski ◽  
Niels Hovius
Keyword(s):  
Temporal Variability ◽  
Human Life ◽  
Weather Data ◽  
Spatial And Temporal Variability ◽  
Resolution Time ◽  
Mountainous Regions ◽  
Direct Observations ◽  
Lag Times ◽  
Process Domains

<p>Rockfalls are a substantial geohazard to human life and infrastructure in mountainous regions but we still lack detailed understanding of when and where rockfalls occur, and which environmental conditions lead to rockfall over diurnal, seasonal and annual timescales. This is due to the fact that direct observations in alpine landscapes are difficult to make and long, high-resolution time series of measurements are rare. Using seismic techniques, we can collect near-complete catalogues of geomorphic events and record their distributions in time and space. This allows studying the interaction of process domains, the role of various rockfall triggers, and lead and lag times with unprecedented detail.</p><p>We use the unique six-year long seismic dataset of the Reintal rockfall observatory in the German Alps to detect, classify and locate rockfalls in the Reintal catchment. This rockfall catalogue enables us to analyse the spatial and temporal variability of rockfalls spanning several orders of magnitude in size. We test the hypothesis that variations of rockfall in the Reintal catchment are dominated by seasonal patterns. In combination with weather data, we examine boundary conditions, drivers and triggers of rockfalls in this alpine catchment.</p>

scholarly journals Rayleigh lidar observations of double stratopause structure over three different northern hemisphere stations

2006 ◽  
Vol 6 (4) ◽  
pp. 6933-6956 ◽  
Author(s):  
V. Sivakumar ◽  
H. Bencherif ◽  
A. Hauchecorne ◽  
P. Keckhut ◽  
D. N. Rao ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Northern Hemisphere ◽  
Planetary Wave ◽  
Middle Level ◽  
Lidar Data ◽  
Upper Level ◽  
Rayleigh Lidar ◽  
First Time ◽  
Lidar Observations

Abstract. Using four years of Rayleigh lidar data collected from three different northern hemisphere stations (Gadanki 13.5° N, 79.2° E ; Mt. Abu 24.5° N, 72.7° E and Observatoire de Haute Provence: OHP; 44° N, 6° E), the characteristics of double (separated) stratopause occurrence are presented here, for the first time. The characteristics are illustrated by a seasonal change during summer and winter and the variation in percentage of occurrence from place to place. It is found that the over-all mean normal stratopause (NS) positioned at the middle level of double stratopause (upper and lower level) with its location nearer to the lower level of double stratopause (LDS) than to the upper level of double stratopause (UDS). The frequency distribution of NS, LDS and UDS demonstrated variability with location, indicating role of dynamical activity. By making use of a quasi-continuous 40 days of lidar observations over Gadanki and OHP, the responsibility of Gravity Wave (GW) and Planetary Wave (PW) activity for the LDS and UDS occurrence are examined and presented.

Sign in / Sign up

Export Citation Format

Share Document