In situ measurements of attenuation coefficient for evaluating the hardness of cataract lens by a high frequency ultrasonic needle transducer

2009 ◽  
Author(s):  
Chih-Chung Huang ◽  
Ruimin Chen ◽  
Po-Hsiang Tsui ◽  
Qifa Zhou ◽  
Mark S. Humayun ◽  
...  
Keyword(s):  
Attenuation Coefficient ◽  
High Frequency ◽  
In Situ Measurements

scholarly journals Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Brian Helmuth ◽  
Francis Choi ◽  
Allison Matzelle ◽  
Jessica L. Torossian ◽  
Scott L. Morello ◽  
...  
Keyword(s):  
High Frequency ◽  
In Situ Measurements ◽  
Mussel Bed ◽  
Intertidal Mussel

scholarly journals A five year record of high-frequency in situ measurements of non-methane hydrocarbons at Mace Head, Ireland

2011 ◽  
Vol 4 (5) ◽  
pp. 955-964 ◽  
Author(s):  
A. Grant ◽  
E. L. Yates ◽  
P. G. Simmonds ◽  
R. G. Derwent ◽  
A. J. Manning ◽  
...  
Keyword(s):  
High Frequency ◽  
Temporal Trends ◽  
Kendall Test ◽  
In Situ Measurements ◽  
Baseline Data ◽  
Seasonal Cycles ◽  
Air Masses ◽  
Northern Hemispheric ◽  
Eastern Edge

Abstract. Continuous high-frequency in situ measurements of a range of non-methane hydrocarbons have been made at Mace Head since January 2005. Mace Head is a background Northern Hemispheric site situated on the eastern edge of the Atlantic. Five year measurements (2005–2009) of six C2–C5 non-methane hydrocarbons have been separated into baseline Northern Hemispheric and European polluted air masses, among other sectors. Seasonal cycles in baseline Northern Hemispheric air masses and European polluted air masses arriving at Mace Head have been studied. Baseline air masses show a broad summer minima between June and September for shorter lived species, longer lived species show summer minima in July/August. All species displayed a winter maxima in February. European air masses showed baseline elevated mole fractions for all non-methane hydrocarbons. Largest elevations (of up to 360 ppt for ethane maxima) from baseline data were observed in winter maxima, with smaller elevations observed during the summer. Analysis of temporal trends using the Mann-Kendall test showed small (<6 % yr−1) but statistically significant decreases in the butanes and i-pentane between 2005 and 2009 in European air. No significant trends were found for any species in baseline air.

scholarly journals In-situ multispectral and bathymetric measurements over a supraglacial lake in western Greenland using a remotely controlled watercraft

2011 ◽  
Vol 5 (1) ◽  
pp. 479-498
Author(s):  
M. Tedesco ◽  
N. Steiner
Keyword(s):  
Attenuation Coefficient ◽  
Attenuation Factor ◽  
In Situ Measurements ◽  
Shallow Waters ◽  
Lake Depth ◽  
In Situ Data ◽  
Lake Bottom ◽  
Exponential Trend ◽  
Bottom Albedo

Abstract. We report concurrent in-situ multi-spectral and depth measurements over a supraglacial lake in West Greenland, collected by means of a remotely controlled boat equipped with a GPS, a sonar and a spectrometer. We focus our attention on the analysis of some of the key parameters widely used for multispectral spaceborne bathymetry, namely the lake bottom albedo and the water attenuation coefficient. The analysis of in-situ data highlights the exponential trend of the water-leaving reflectance with lake depth. The values of the attenuation factor are obtained from in-situ data and compared with those computed using approaches proposed in the literature. Also, the values of the lake bottom albedo from in-situ measurements are compared with those obtained from the analysis of reflectance of shallow-waters. Finally, we quantify the error between in-situ measured and satellite-estimated lake depth values for the lake under study.

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