scholarly journals On the Vertical Distribution of the Light from Lighthouses Placed at High Elevations above the Sea-Level

Nature ◽  
1878 ◽  
Vol 19 (471) ◽  
pp. 19-20
Author(s):  
T. STEVENSON
2014 ◽  
Vol 7 (1) ◽  
pp. 105-119 ◽  
Author(s):  
Rajmund Skowron ◽  
Adam Piasecki

Abstract This study presents the results of monthly examinations of the vertical distribution of water thermal structure (2008-2011) carried out over a four-year period in the deepest lakes located in the Kashubian and Brodnickie Lakelands and the Tuchola Forest1. Three lakes were selected for examination (Raduńskie Górne, Zbiczno and Ostrowite). Their maximum depths slightly exceed 40 m, and their surface areas range from 121 to 362.5 ha. The results of the measurements show that, despite only minor differences in depth, water temperature varied significantly between the studied lakes. These differences were mainly apparent in the extent of the epilimnion, water thermal stratification, and in the water temperature in the bottom-most layers in summer and winter. The diversity in thermal stratification of the lakes is mainly determined by their morphometric properties, their location above sea level, and the dynamic influences of winds.


2020 ◽  
pp. 16-25
Author(s):  
I. Brovchenko ◽  
◽  
V. Maderich ◽  
К. Тerletska ◽  
A. Bezhenar ◽  
...  

The objective of the study is to simulate using numerical methods the seasonal and intraseasonal variations of circula-tion, sea level, temperature and salinity in the Bellingshausen Sea and on the shelf of the western part of the Antarctic Penin-sula (WAP). The Semi-implicit Cross-scale Hydroscience Integrated System Model with an unstructured triangular horizontal grid and a vertical local sigma coordinate system and ice dynamic-thermodynamic Finite-Element Sea Ice Model were applied. Heat, momentum and salt fluxes were set on the ocean surface using the ERA5 reanalysis data. At the open boundaries, the vertical distribution of temperature and salinity was determined according to the COPERNICUS reanalysis. At the western open boundary of the computational domain, the vertical distribution of velocity of currents from COPERNICUS was also specified, whereas at the open eastern boundary the level deviations were specified. Time variability analysis of sea level wasperformed using wavelet analysis. The results of modelling of the sea level, temperature, and salinity fields for 2014–2015 were compared with the available observational data on the shelf of the WAP, including data from the Ukrainian Antarctic Expedition. The simulated horizontal and vertical distributions of the subsurface layer with minimum of potential temperature Tmin (Winter Water) are given. The depth of the Tmin varies in the range of 10–100 m increasing to the north. The values of minimum of po-tential temperature Tmin also increase to the north from –1.8 to 1.2 °C. The intraseasonal oscillations of sea level computed by the model for 2014—2015 were analysed together with data of observations at the tidal stations Faraday/Akademik Vernadsky and Rothera located at the coast of WAP. In the range 1–150 days the largest amplitudes of the level scalegrams were found for a period of approximately 100 days in 2014 and 120 days in 2015 at both stations. The largest amplitudes of modelled level scale-grams were observed with a period of approximately 88 days in 2014 and 80 days in 2015 at both stations. The largest amplitudesof scalegrams for Antarctic Oscillation (AAO) were found for a period of 105 days in 2014 and 123 days in 2015. The corresponding correlation coefficients between observed sea level scalegrams and AAO for 2014 were 0.84 and 0.86, respectively, whereas for 2015 they were 0.87 and 0.90, respectively. It was concluded that the relationship between intraseasonal processes in the ocean in West Antarctica and AAO existed at a time scale of about 100 days.


Tellus B ◽  
2011 ◽  
Vol 63 (1) ◽  
Author(s):  
Abhay Devasthale ◽  
Michael Tjernström ◽  
Karl-Göran Karlsson ◽  
Manu Anna Thomas ◽  
Colin Jones ◽  
...  

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Katie E. Miles ◽  
Bryn Hubbard ◽  
Evan S. Miles ◽  
Duncan J. Quincey ◽  
Ann V. Rowan ◽  
...  

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.


2021 ◽  
Vol 42 (17) ◽  
pp. 6421-6436
Author(s):  
Sourita Saha ◽  
Som Sharma ◽  
K. Niranjan Kumar ◽  
Prashant Kumar ◽  
Vaidehi Joshi ◽  
...  

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