Travelling disturbances in the ionosphere

1950 ◽  
Vol 202 (1069) ◽  
pp. 208-223 ◽  
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Sudden Change ◽  
Frequent Occurrence ◽  
Vertical Movements ◽  
Short Period ◽  
The Mean ◽  
The Vertical Distribution

Methods have been developed for the examination of the horizontal and vertical movements of short-period disturbances in the ionosphere. It has been found that quasi-periodic travelling disturbances with periods of from 10 to 60 min. are of frequent occurrence in the F region by day. They appear as temporary variations in the vertical distribution of ionization which show a horizontal progression and a vertical progression downwards. The horizontal directions of travel have a well-defined mean direction on most days. The mean direction shows a marked seasonal variation with a sudden change at each equinox. The horizontal rate of travel is usually between 5 and 10 km./min., and the rate of vertical progression downwards is approximately half the horizontal rate. The disturbances are considered to be variations of a compressional type in the atmosphere resulting in changes in the distribution of ionization.

scholarly journals Continuous borehole optical televiewing reveals variable englacial debris concentrations at Khumbu Glacier, Nepal

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katie E. Miles ◽  
Bryn Hubbard ◽  
Evan S. Miles ◽  
Duncan J. Quincey ◽  
Ann V. Rowan ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Water Supply ◽  
Depth Profile ◽  
Variable Thickness ◽  
Surface Melting ◽  
High Mountain ◽  
Ablation Area ◽  
The Mean ◽  
Surface Melt ◽  
The Vertical Distribution

AbstractSurface melting of High Mountain Asian debris-covered glaciers shapes the seasonal water supply to millions of people. This melt is strongly influenced by the spatially variable thickness of the supraglacial debris layer, which is itself partially controlled by englacial debris concentration and melt-out. Here, we present measurements of deep englacial debris concentrations from debris-covered Khumbu Glacier, Nepal, based on four borehole optical televiewer logs, each up to 150 m long. The mean borehole englacial debris content is ≤ 0.7% by volume in the glacier’s mid-to-upper ablation area, and increases to 6.4% by volume near the terminus. These concentrations are higher than those reported for other valley glaciers, although those measurements relate to discrete samples while our approach yields a continuous depth profile. The vertical distribution of englacial debris increases with depth, but is also highly variable, which will complicate predictions of future rates of surface melt and debris exhumation at such glaciers.

Daily inundation induced seasonal variation in the vertical distribution of soil water salinity in an estuarine mangrove forest under a tropical monsoon climate

2020 ◽  
Vol 35 (4) ◽  
pp. 638-649
Author(s):  
Akira Komiyama ◽  
Sasitorn Poungparn ◽  
Suthathip Umnouysin ◽  
Chadtip Rodtassana ◽  
Shogo Kato ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Soil Water ◽  
Mangrove Forest ◽  
Water Salinity ◽  
Monsoon Climate ◽  
Tropical Monsoon ◽  
The Vertical Distribution

scholarly journals Vertical movements of “escaped” farmed Atlantic salmon (Salmo salar L.)—a simulation study in a western Norwegian fjord

2009 ◽  
Vol 66 (2) ◽  
pp. 278-288 ◽  
Author(s):  
Ove T. Skilbrei ◽  
Jens Christian Holst ◽  
Lars Asplin ◽  
Marianne Holm
Keyword(s):  
Atlantic Salmon ◽  
Vertical Distribution ◽  
Salmo Salar ◽  
Simulation Study ◽  
Vertical Movements ◽  
Atlantic Salmon Salmo Salar ◽  
Wide Range ◽  
Norwegian Fjord ◽  
Farmed Atlantic Salmon ◽  
The Vertical Distribution

Abstract Skilbrei, O. T., Holst, J. C., Asplin, L., and Holm, M. 2009. Vertical movements of “escaped” farmed Atlantic salmon (Salmo salar L.)—a simulation study in a western Norwegian fjord. – ICES Journal of Marine Science, 66: 278–288. To study the vertical distribution of fish that had been allowed to escape, farmed Atlantic salmon were tagged with acoustic tags equipped with depth sensors, and then released on five different dates in the course of a year from two fish farms in the Hardanger Fjord in western Norway. Release stimulated the fish to dive to deeper than 15 m during the first hours or days post-release, often down to 50–80 m. However, during the following 4 weeks, most of the escapees spent most of their time above the pycnocline at depths of 0–4 m. The fish were more widely distributed in the water column after release during winter, but still spent most of the time in the cold surface layers. There was a wide range in the vertical distribution of individual fish, and the proportion of detections below 14-m depth ranged from 0 to 90%. There was a significant diurnal cycle in all seasons except midsummer, when the fish were less abundant in the upper layer during daylight, especially on brighter days. The results suggest that salmon diving activity following escape may complicate the recapture of escaped fish at the farm site but that the subsequent tendency of most fish to stay near the surface, virtually irrespective of the time of year, may facilitate recapture.

Seasonal and Diurnal Vertical Distribution of Herring (Clupea harengus L.) in Passamaquoddy, Bay, N.B.

1960 ◽  
Vol 17 (5) ◽  
pp. 699-711 ◽  
Author(s):  
Vivien M. Brawn
Keyword(s):  
Solar Radiation ◽  
Vertical Distribution ◽  
Water Temperature ◽  
Inverse Correlation ◽  
Clupea Harengus ◽  
Significant Inverse Correlation ◽  
Vertical Movements ◽  
Passamaquoddy Bay ◽  
The Mean ◽  
Echo Sounder

The depth of schools of immature herring in Passamaquoddy Bay was determined from echo-sounder records taken from 1947 to 1958. The records gave no information on the presence of herring between the surface and 14 ft, and any herring in this zone have been omitted from the calculations. The herring schools showed diurnal vertical movements, being closer to the surface by night than by day in every month of the year. From May until December the median depth varied from 30 to 44 ft by day and from 21 to 26 ft by night. From January to April the schools were deeper in the water by day with a median depth of 83 to 126 ft, though still rising towards the surface at night, to a median depth of 36 ft in February. No correlation was found between the mean solar radiation for the daylight hours and the median depth of herring by day in each month. Between 2° and 4–7 °C there was a significant inverse correlation between water temperature and the depth of the herring by day, but as temperature increased above 7 °C, up to 12°, there was no further decrease in median depth.

scholarly journals On the spatial variability of the regional aerosol distribution as determined from ceilometers

2020 ◽  
Author(s):  
Matthias Wiegner ◽  
Alexander Geiß ◽  
Ina Mattis ◽  
Fred Meier ◽  
Thomas Ruhtz
Keyword(s):  
Vertical Distribution ◽  
Mixing Layer ◽  
Data Set ◽  
Integrated Backscatter ◽  
Aerosol Distribution ◽  
Mixing Layer Height ◽  
Aerosol Sources ◽  
The Mean ◽  
Two Parameters ◽  
The Vertical Distribution

Abstract. Measurements of the vertical distribution of aerosol particles are typically only available at selected sites leaving the question of their representativeness for urban and regional scales unanswered. As a contribution to solve this problem we have investigated ceilometer signals from two testbeds in Munich and Berlin, Germany. For each testbed measurements of 24 months from 6 ceilometers were available. This constitutes a unique data set, in particular as the same type of instruments are deployed and the same data evaluation schemes applied. Two parameters are discussed: the mixing layer height (MLH) as an indicator for the vertical distribution and the integrated backscatter as a proxy for the amount of aerosols in the mixing layer. The MLH was determined by the COBOLT algorithm, the integrated backscatter from the Klett (backward and forward) inversion scheme. It was found that the mean difference of the MLH at two sites within a testbed typically only varies by less than 50 m, slightly increasing with the distance of the corresponding sites. Almost 60 % of all intercomparisons agree within ±100 m. MLHs are typically correlated with R > 0.9 in particular for the Berlin-testbed. With respect to the integrated backscatter the correlation is in the range of 0.7 < R < 0.9. This is expected from the diversity of local aerosol sources within a given testbed. We conclude from our data that the MLH determined from a single ceilometer is applicable for a whole metropolitan area. However, the integrated backscatter of particles within the mixing layer exhibits a variability of 15–25 % suggesting that one ceilometer is not representative, especially if atmospheric processes shall be investigated.

scholarly journals Seasonal variation in the vertical distribution of zone over Oakshin Gangotri, Antarctica

MAUSAM ◽  
2021 ◽  
Vol 42 (3) ◽  
pp. 275-278
Author(s):  
A.L. KOPPAR ◽  
S.C. NAGRATH
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
Early Spring ◽  
The Other ◽  
Late Winter ◽  
Double Peak ◽  
The Vertical Distribution

Ozone soundings made from Dakshin Gangotri, Antarctica during 1987 are presented. The vertical distribution of ozone over Antarctica is characterised by a double peak profile, one around 200-150 hPa and the other around 50 hPa. During late winter-early spring the upper peak is considerably depleted. Tropospheric ozoe remains low and nearly constant throughout the year.  

Occurrence of discontinuities in the ozone concentration data from three reanalyses

2020 ◽  
Author(s):  
Peter Krizan
Keyword(s):  
Vertical Distribution ◽  
Data Quality ◽  
Ozone Concentration ◽  
Frequent Occurrence ◽  
Homogeneity Test ◽  
Concentration Data ◽  
Trend Analyses ◽  
Ozone Data ◽  
Before And After ◽  
The Vertical Distribution

&lt;p&gt;The aim of this presentation is to compare the occurrence of discontinuities in the ozone concentration data from the MERRA-2, ERA-5 and JRA-55 reanalyse, with the help of the Pettitt homogeneity test. We distinguish between the significant and insignificant discontinuities, according to the relation between the dispersion and the average ozone values before and after the discontinuity.&amp;#160;&amp;#160; &amp;#160;This occurrence is important for trend analyses, because the presence of discontinuities influences the values of trends and their significance. Discontinuities arise from the changing in the assimilation procedure, introducing new observation to the reanalyse, and changing of data quality. We search for their spatial, temporal and geographical occurrence. There are differences among these reanalyses. In the case of the MERRA-2 data, the transition from SBUV to EOS Aura data in 2004 has great impact on discontinuity behaviour. The frequent occurrence of discontinuities is seen in the uppermost model layers. The uppermost MERRA-2 layer is 0.1 hPa, while for ERA-5 this layer is 1 hPa. So there are differences in the vertical distribution of discontinuities among the reanalyses. The ozone data with the strong occurrence of the significant discontinuities is not suitable for trend analyses. &amp;#160;&amp;#160;&lt;/p&gt;

Vertical distribution, seasonality and troposphericity of ice-supersaturated air masses in the northern mid-latitudes from regular in-situ observations by passenger aircraft

2020 ◽  
Author(s):  
Andreas Petzold ◽  
Susanne Rohs ◽  
Mihal Rütimann ◽  
Patrick Neis ◽  
Berkes Florian ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Vertical Distribution ◽  
North Atlantic ◽  
Observation Data ◽  
European Research ◽  
Air Masses ◽  
The North ◽  
The North Atlantic ◽  
Passenger Aircraft ◽  
The Vertical Distribution

&lt;p&gt;The vertical distribution and seasonal variation of water vapour volume mixing ratio (H&lt;sub&gt;2&lt;/sub&gt;O VMR), relative humidity with respect to ice (RH&lt;sub&gt;ice&lt;/sub&gt;) and particularly of regions with ice-supersaturated air masses (ISSR) in the extratropical upper troposphere and lowermost stratosphere are investigated at northern mid-latitudes over the regions Eastern North America, the North Atlantic and Europe for the period 1995 to 2010.&lt;/p&gt;&lt;p&gt;Observation data originate from regular and continuous long-term measurements of H&lt;sub&gt;2&lt;/sub&gt;O VMR, temperature and RH&lt;sub&gt;ice&lt;/sub&gt; by instrumented passenger aircraft in the framework of the European research program MOZAIC which is continued as European research infrastructure IAGOS (from 2011; see www.iagos.org). The observation data are analysed with respect to the thermal and dynamical tropopauses, as provided by ERA-Interim. Additionally, collocated O&lt;sub&gt;3&lt;/sub&gt; observations from MOZAIC are used as tracer for stratospheric air masses.&lt;/p&gt;&lt;p&gt;Our key results provide in-depth insight into seasonal and regional variability and tropospheric nature of ice-supersaturated air masses at various distances from the tropopause layer. For the vertical distribution and seasonal variation of ISSR occurrence we show a comparison of our results to radio soundings and to satellite observations of cirrus cloud occurrence from AIRS and TOVs Path B instruments. Finally, for all three regions, we investigate the trends and the dependencies of ISSR occurrence on the North Atlantic Oscillation (NAO) index.&lt;/p&gt;

Predicting the vertical distribution of the opossum shrimp, Mysis relicta, in Lake Ontario: a test of laboratory-based light preferences

2009 ◽  
Vol 66 (1) ◽  
pp. 101-113 ◽  
Author(s):  
Brent T. Boscarino ◽  
Lars G. Rudstam ◽  
Ellis R. Loew ◽  
Edward L. Mills
Keyword(s):  
Vertical Distribution ◽  
Thermal Conditions ◽  
Lake Ontario ◽  
Equal Weight ◽  
Mysis Relicta ◽  
Vertical Movements ◽  
Light Levels ◽  
Preference Functions ◽  
The Vertical Distribution ◽  
Mysid Shrimp

Light and temperature strongly influence the vertical distribution of the mysid shrimp, Mysis relicta . We monitored the vertical movements and depth selection behavior of mysids exposed to different light intensities and light–temperature gradients in the laboratory and derived a mysid light preference function in units relevant to mysid vision: “mylux”. Mysids preferred light levels between 10−8 and 10−7 mylux (∼10−6 to 10−5 lux) and rarely moved into waters of 10−3 mylux (∼0.1 lux) and greater. A model that assumed equal weight and independence of mysid light and temperature preference functions successfully predicted the proportion of mysids found in two different temperature–light combinations in the laboratory. This model also predicted the depth of maximum mysid density to within 2 m on two spring nights and within 5 m on two summer nights of varying moon phase and thermal conditions in Lake Ontario. This study provides novel insights into how temperature and light interact to influence the vertical distribution of mysids. Our model may be used to predict mysid vertical distribution in any deepwater system inhabited by mysids in which the primary mysid predators are visual feeders.

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