scholarly journals Simultaneous generalized and low-layer SCIDAR turbulence profiles at san pedro mártir observatory

2019 ◽  
Vol 490 (1) ◽  
pp. 1397-1405 ◽  
Author(s):  
R Avila ◽  
O Valdés-Hernández ◽  
L J Sánchez ◽  
I Cruz-González ◽  
J L Avilés ◽  
...  
Keyword(s):  
High Altitude ◽  
Wind Direction ◽  
Close Agreement ◽  
Baja California ◽  
Ground Level ◽  
Combined Effect ◽  
Moderate Altitude ◽  
San Pedro ◽  
Simultaneous Measurements

ABSTRACT We present optical turbulence profiles obtained with a Generalized SCIDAR (G-SCIDAR) and a low-layer SCIDAR (LOLAS) at the Observatorio Astronómico Nacional in San Pedro Mártir (OAN-SPM), Baja California, Mexico, during three observing campaigns in 2013, 2014, and 2015. The G-SCIDAR delivers profiles with moderate altitude-resolution (a few hundred metres) along the entire turbulent section of the atmosphere, while the LOLAS gives high altitude resolution (on the order of tens of metres) but only within the first few hundred metres. Simultaneous measurements were obtained on 2014 and allowed us to characterize in detail the combined effect of the local orography and wind direction on the turbulence distribution close to the ground. At the beginning of several nights, the LOLAS profiles show that turbulence peaks between 25 and 50 m above the ground, not at ground level as was expected. The G-SCIDAR profiles exhibit a peak within the first kilometre. In 55 per cent and 36 per cent of the nights stable layers are detected between 10 and 15 km and at 3 km, respectively. This distribution is consistent with the results obtained with a G-SCIDAR in 1997 and 2000 observing campaigns. Statistics computed with the 7891 profiles that have been measured at the OAN-SPM with a G-SCIDAR in 1997, 2000, 2014, and 2015 campaigns are presented. The seeing values calculated with each of those profiles have a median of 0.79, first and third quartiles of 0.51 and 1.08 arcsec, which are in close agreement with other long term seeing monitoring performed at the OAN-SPM.

scholarly journals Combined Effect of Body Mass Index and Renal Function on Long-Term Clinical Outcomes in Elderly Adults After Percutaneous Coronary Intervention

2016 ◽  
Vol 64 (9) ◽  
pp. e39-e41
Author(s):  
Ryo Naito ◽  
Katsumi Miyauchi ◽  
Hirokazu Konishi ◽  
Shuta Tsuboi ◽  
Manabu Ogita ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Percutaneous Coronary Intervention ◽  
Renal Function ◽  
Clinical Outcomes ◽  
Body Mass ◽  
Coronary Intervention ◽  
Combined Effect ◽  
Elderly Adults ◽  
Percutaneous Coronary

Californian mixed-conifer forests under unmanaged fire regimes in the Sierra San Pedro Martir, Baja California, Mexico

2000 ◽  
Vol 27 (1) ◽  
pp. 105-129 ◽  
Author(s):  
R. A. Minnich ◽  
M. G. Barbour ◽  
J. H. Burk ◽  
J. Sosa-Ramirez
Keyword(s):  
Baja California ◽  
Fire Regimes ◽  
Conifer Forests ◽  
Mixed Conifer ◽  
San Pedro ◽  
Mixed Conifer Forests ◽  
Sierra San Pedro Martir

scholarly journals Long-term O<sub>3</sub>–precursor relationships in Hong Kong: field observation and model simulation

2017 ◽  
Vol 17 (18) ◽  
pp. 10919-10935 ◽  
Author(s):  
Yu Wang ◽  
Hao Wang ◽  
Hai Guo ◽  
Xiaopu Lyu ◽  
Hairong Cheng ◽  
...  
Keyword(s):  
Hong Kong ◽  
Model Simulation ◽  
Ground Level ◽  
Effective Control ◽  
Photochemical Pollution ◽  
Mixing Ratios ◽  
The Past ◽  
Total Volatile Organic Compounds

Abstract. Over the past 10 years (2005–2014), ground-level O3 in Hong Kong has consistently increased in all seasons except winter, despite the yearly reduction of its precursors, i.e. nitrogen oxides (NOx =  NO + NO2), total volatile organic compounds (TVOCs), and carbon monoxide (CO). To explain the contradictory phenomena, an observation-based box model (OBM) coupled with CB05 mechanism was applied in order to understand the influence of both locally produced O3 and regional transport. The simulation of locally produced O3 showed an increasing trend in spring, a decreasing trend in autumn, and no changes in summer and winter. The O3 increase in spring was caused by the net effect of more rapid decrease in NO titration and unchanged TVOC reactivity despite decreased TVOC mixing ratios, while the decreased local O3 formation in autumn was mainly due to the reduction of aromatic VOC mixing ratios and the TVOC reactivity and much slower decrease in NO titration. However, the decreased in situ O3 formation in autumn was overridden by the regional contribution, resulting in elevated O3 observations. Furthermore, the OBM-derived relative incremental reactivity indicated that the O3 formation was VOC-limited in all seasons, and that the long-term O3 formation was more sensitive to VOCs and less to NOx and CO in the past 10 years. In addition, the OBM results found that the contributions of aromatics to O3 formation decreased in all seasons of these years, particularly in autumn, probably due to the effective control of solvent-related sources. In contrast, the contributions of alkenes increased, suggesting a continuing need to reduce traffic emissions. The findings provide updated information on photochemical pollution and its impact in Hong Kong.

scholarly journals Aging of stimulus-driven and goal-directed attentional processes in young immigrants with long-term high altitude exposure in Tibet: An ERP study

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Hailin Ma ◽  
Xiaoyan Huang ◽  
Ming Liu ◽  
Huifang Ma ◽  
Delong Zhang
Keyword(s):  
High Altitude ◽  
Attentional Processes ◽  
Altitude Exposure ◽  
Young Immigrants

scholarly journals A coastal population of Large-blotched Ensatina Ensatina klauberi (Caudata: Plethodontidae) in Baja California, México

Check List ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 1649 ◽  
Author(s):  
Jorge Heriberto Valdez-Villavicencio ◽  
Anny Peralta-Garcia ◽  
Bradford Damion Hollingsworth
Keyword(s):  
Baja California ◽  
Volcanic Field ◽  
Species Range ◽  
Oak Woodlands ◽  
Coastal Population ◽  
San Pedro ◽  
Sierra San Pedro Martir

We found a new population of Ensatina klauberi in San Quintín volcanic field, Baja California. It represents the first coastal population of this species. This record extends the species range ca. 71 km southwest of the southernmost record of E. klauberi in the Sierra San Pedro Mártir and represents the first population discovered outside of coniferous and pine-oak woodlands.

scholarly journals First marlin archival tagging study suggests new direction for research

2019 ◽  
Vol 70 (4) ◽  
pp. 603 ◽  
Author(s):  
Michael L. Domeier ◽  
Sofia Ortega-Garcia ◽  
Nicole Nasby-Lucas ◽  
Paxson Offield
Keyword(s):  
Peritoneal Cavity ◽  
Baja California ◽  
Tracking Data ◽  
Recovery Rates ◽  
Geographic Position ◽  
Archival Tags ◽  
Fish Tracking ◽  
Tag Shedding

Decades of billfish tagging studies have been hindered by below-par conventional tag recovery rates and high rates of premature satellite pop-up tag shedding. With hopes of obtaining long-term tracking data, we performed the world’s first archival tagging study on an istiophorid, surgically implanting 99 archival tags into the peritoneal cavity of striped marlin (Kajikia audax) off the coast of Baja California, Mexico. Marlin were also tagged externally with a conventional tag before release. Ten archival tags (10.1%) were recovered with days at liberty (DAL) ranging from 400 to 2795. Nine recoveries were from Mexican waters, whereas one marlin was recaptured off Ecuador. In total, 100% of the light stalks on the archival tags failed, with nine failing within the first 3 months of deployment; because the light data are used to estimate the geographic position of the tagged fish, tracking data were compromised. The absence of conventional tags on all recaptured marlin indicates that studies of marlin using conventional tags have been hindered by tag shedding rather than tagging-associated mortality or underreporting. Our high recapture rate and long DAL suggest istiophorid science could be greatly advanced by archival tagging if new tag designs or methods can eliminate tag failure.

scholarly journals Overview of a prescribed burning experiment within a boreal forest in Finland

2013 ◽  
Vol 13 (8) ◽  
pp. 21703-21763 ◽  
Author(s):  
A. Virkkula ◽  
J. Levula ◽  
T. Pohja ◽  
P. P. Aalto ◽  
P. Keronen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Radiative Forcing ◽  
Prescribed Burning ◽  
Geometric Mean ◽  
Sonic Anemometer ◽  
Ground Level ◽  
Organic Layer ◽  
Available Nitrogen ◽  
Mean Diameter

Abstract. A prescribed burning of a boreal forest was conducted on 26 June 2009 in Hyytiälä, Finland, to study aerosol and trace gas emissions from wildfires and the effects of fire on soil properties in a controlled environment. A 0.8 ha forest near the SMEAR II was cut clear; some tree trunks, all tree tops and branches were left on the ground and burned. The amount of burned organic material was ~46.8 t (i.e., ~60 t ha−1). The flaming phase lasted 2 h 15 min, the smoldering phase 3 h. Measurements were conducted on the ground with both fixed and mobile instrumentation, and from a research aircraft. In the middle of the burning area, CO2 concentration peaks were around 2000–3000 ppm above the baseline and peak vertical flow velocities were 6 ± 3 m s−1, as measured a 10-Hz 3-D sonic anemometer placed within the burn area. Peak particle number concentrations were approximately 1–2 × 106 cm−3 in the plume at a distance of 100–200 m from the burn area. The geometric mean diameter of the mode with the highest concentration was at 80 ± 1 nm during the flaming phase and in the middle of the smoldering phase but at the end of the smoldering phase the largest mode was at 122 nm. In the volume size distributions geometric mean diameter of the largest volume mode was at 153 nm during the flaming phase and at 300 nm during the smoldering phase. The lowest single-scattering albedo of the ground-level measurents was 0.7 in the flaming-phase plume and ~0.9 in the smoldering phase. The radiative forcing efficiency was negative above dark surfaces, in other words, the particles cool the atmosphere. Elevated concentrations of several VOCs (including acetonitrile which is a biomass burning marker) were observed in the smoke plume at ground level. The forest floor (i.e., richly organic layer of soil and debris, characteristic of forested land) measurements showed that VOC fluxes were generally low and consisted mainly of monoterpenes, but a clear peak of VOC flux was observed after the burning. After one year, the fluxes were nearly stabilised close to the level before the burning. The clearcutting and burning of slash increased the total long-term CO2 release from the soil, altered the soil's physical, chemical and biological properties such as increased the available nitrogen contents of the soil, which in turn, affected the level of the long-term fluxes of greenhouse gases.

scholarly journals Dollar’s Influence on Crude Oil and Gold Based on MF-DPCCA Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhonghui Ding ◽  
Kai Shi ◽  
Bin Wang
Keyword(s):  
Correlation Analysis ◽  
Crude Oil ◽  
Cross Correlation ◽  
Combined Effect ◽  
Analysis Method ◽  
Correlation Relationship ◽  
Cross Correlation Analysis ◽  
Correlation Analysis Method ◽  
Phase Randomization

This paper analyzed the influence of dollar on crude oil and gold based on the multifractal detrended partial cross-correlation analysis method. It showed that affected by the dollar, the crude oil and gold markets have a partial cross-correlation relationship which is stronger than their own cross-correlation. The partial cross-correlation is long-term and has multifractal characteristics. Through shuffled and Fourier-phase randomization, it is found that this multifractal feature is caused by the combined effect of the long-term cross-correlation between the returns and the fluctuation fat-tailed distribution, where the influence of the fat-tailed distribution is slightly greater than that of the long-term cross-correlation between the returns.

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