Search results for "Altitude"

Depletion of ozone and reservoir species of chlorine and nitrogen oxide in the lower Antarctic polar vortex measured from aircraft

2017

Novel airborne in situ measurements of inorganic chlorine, nitrogen oxide species, and ozone were performed inside the lower Antarctic polar vortex and at its edge in September 2012. We focus on one flight during the Transport and Composition of the LMS/Earth System Model Validation (TACTS/ESMVal) campaign with the German research aircraft HALO (High-Altitude LOng range research aircraft), reaching latitudes of 65°S and potential temperatures up to 405 K. Using the early winter correlations of reactive trace gases with N2O from the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), we find high depletion of chlorine reservoir gases up to ∼40% (0.8 ppbv) at 12 km to 1…

Production altitude and time delays of the terrestrial gamma flashes: Revisiting the Burst and Transient Source Experiment spectra

2008

[1] On the basis of the RHESSI results it has been suggested that terrestrial gamma flashes (TGFs) are produced at very low altitudes. On the other hand some of the Burst and Transient Source Experiment (BATSE) spectra show unabsorbed fluxes of X rays in the 25–50 keV energy range, indicating a higher production altitude. To investigate this, we have developed a Monte Carlo code for X-ray propagation through the atmosphere. The most important features seen in the modeled spectra are (1) a low-energy cutoff which moves to lower energies as TGFs are produced at higher altitudes, (2) a high-energy cutoff which moves to lower energies as TGFs are observed at larger zenith angles, and (3) time d…

Possible Role of Glymphatic System of the Brain in the Pathogenesis of High-Altitude Cerebral Edema

2018

Simka, Marian, Paweł Latacz, and Joanna Czaja. Possible role of glymphatic system of the brain in the pathogenesis of high-altitude cerebral edema. High Alt Med Biol. 19:394–397, 2018.—In this article, we suggest that the glymphatic system of the brain can play an important role in the pathogenesis of high-altitude cerebral edema (HACE). Water enters the intercellular space of the brain primarily through aquaporin-4 (AQP-4) water channels, the main component of the glymphatic system, whereas acetazolamide, pharmacological agent used in the prevention of HACE, is the blocker of the AQP-4 molecule. In animal experiments, cerebral edema caused by hypobaric hypoxia was associated with an increa…

PHYTOSEIIDAE (ACARI: PARASITIFORMES) OF SICILY (ITALY): SPECIES DIVERSITY AFTER HALF A CENTURY OF SURVEYS

2020

Gli acari fitoseiidi sono divenuti interesse di studio in Sicilia a partire dai primi anni '70. Ricerche costanti nel tempo hanno arricchito le conoscenze sulla fauna siciliana con la segnalazione di 48 specie valide, cinque delle quali nuove per la Scienza. Nel presente lavoro riassumiamo i dati raccolti in circa cinquant'anni, con l’aggiunta di 12 nuove segnalazioni per la fauna isolana. Typhlodromus (Anthoseius) cryptus Athias-Henriot   stata confermata la specie pi  frequente (39,4%), seguita da Typhlodromus (Typhlodromus) exhilaratus Ragusa (32,6%), Kampimodromus aberrans (Oudemans) (22,9%), Typhlodromus (Anthoseius) rhenanoides Athias-Henriot (19,4%) (18,9%). Alcune specie hanno mostr…

The geography of hybrid speciation in plants

2015

High Arctic aircraft measurements characterising black carbon vertical variability in spring and summer

2019

The vertical distribution of black carbon (BC) particles in the Arctic atmosphere is one of the key parameters controlling their radiative forcing and thus role in Arctic climate change. This work investigates the presence and properties of these light-absorbing aerosols over the High Canadian Arctic (>70∘ N). Airborne campaigns were performed as part of the NETCARE project (Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments) and provided insights into the variability of the vertical distributions of BC particles in summer 2014 and spring 2015. The observation periods covered evolutions of cyclonic disturbances at the polar front, which f…

Bioaerosols in the Amazon rain forest: temporal variations and vertical profiles of Eukarya, Bacteria, and Archaea

2021

The Amazon rain forest plays a major role in global hydrological cycling, and biogenic aerosols are likely to influence the formation of clouds and precipitation. Information about the sources and altitude profiles of primary biological aerosol particles, however, is sparse. We used fluorescence in situ hybridization (FISH), a molecular biological staining technique largely unexplored in aerosol research, to investigate the sources and spatiotemporal distribution of Amazonian bioaerosols on the domain level. We found wet season bioaerosol number concentrations in the range of 1–5 × 105 m−3 accounting for > 70 % of the coarse mode aerosol. Eukaryotic and bacterial particles predominated, …

Relationship between erythemal UV and broadband solar irradiation at high altitude in Northwestern Argentina

2018

An analysis of the broadband solar irradiation, IT, and the erythemal UV irradiation, IUVER, has been performed using the measurements made from 2013 to 2015 at three sites located at altitudes over 1000 m a.s.l. In Northwestern Argentina (Salta, El Rosal, and Tolar Grande). The main objective of this paper is to determine a relationship between IT and IUVER, which would allow to estimate IUVER from IT in places with few IUVER measurements available, and especially in those where is important to establish adequate photoprotection measures given their dense population and location at high altitude. The relationship between the daily values of IUVER and IT has been fitted to a linear regressi…

Applicability of a simple model for computing diffuse solar radiation to locations of the European, African, Asian and North American areas

1992

Abstract It is tested if the correlation type D = K(s/S)−0.25 (sin hn)1.55, 0.2 ⩽ s/S ⩽ 0.9 previously proposed by Coppolino for Italian locations using K = 7.0, allows a reliable estimation of the monthly mean daily diffuse solar radiation D (MJ m−2 day−1), from only the monthly mean daily relative sunshine s/S and the noon altitude of the sun on the 15th of the month hn (degrees) at locations of the European, African, Asian and North American areas. The test is performed at 14 stations in the above areas displaced at various latitudes L, elevations above sea level E and geographical situations, using K = 7.0 for the stations where 0.48 ⩽ (s/S)m, ⩽ 0.63, K = 8.5 for those where 0.40 ⩽ (s/S…

A very simple model for computing global solar radiation

1990

Abstract In this paper a very simple model for predicting the daily global solar radiation at any Italian location using as input of a few extensively measured meterological parameters is proposed. In fact the daily radiation G (MJ m−2) is here correlated only with the sunshine duration s (h) and the noon altitude of the sun on the 15th of the month h n (degrees) by the following equation: G= Ks 0.5 (sin h n ) 1.15 where only one value of the factor K is used. The validity of this formula is verified fixing K = 7.8 and using the data from 34 Italian stations displaced at various latitudes, altitudes or geographical situations (inland or coastal site). The test results show that the deviatio…