Study of a coincident observation between the ROCSAT-1 density irregularity and Ascension Island scintillation

Radio Science ◽  
2012 ◽  
Vol 47 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Y. H. Liu ◽  
C. K. Chao ◽  
S.-Y. Su ◽  
C. H. Liu
Keyword(s):  
Ascension Island ◽  
Density Irregularity

Recent Bairdiidae (Ostracoda) From Ascension Island

Crustaceana ◽  
1975 ◽  
Vol 28 (1) ◽  
pp. 53-65 ◽  
Author(s):  
Rosalie F. Maddocks
Keyword(s):  
Ascension Island

scholarly journals Classification of Ascension Island and Natal ozonesondes using self-organizing maps

2012 ◽  
Vol 117 (D4) ◽  
pp. n/a-n/a ◽  
Author(s):  
Anders A. Jensen ◽  
Anne M. Thompson ◽  
F. J. Schmidlin
Keyword(s):  
Self Organizing Maps ◽  
Ascension Island ◽  
Self Organizing

Angusticopula rowlingiana, a new melosiroid diatom (Bacillariophyta) from Ascension Island (South Atlantic Ocean)

Phytotaxa ◽  
2019 ◽  
Vol 388 (2) ◽  
pp. 155 ◽  
Author(s):  
BART VAN DE VIJVER ◽  
SANDRA WILFERT ◽  
VACLAV HOUK ◽  
DAVID M. JOHN
Keyword(s):  
Electron Microscopy ◽  
New Species ◽  
Atlantic Ocean ◽  
Diatom Species ◽  
Ascension Island ◽  
Remote Island ◽  
A New Species ◽  
Similar Combination ◽  
Southern Atlantic Ocean ◽  
Scanning Electron

During a diatom survey of some samples from Ascension Island, a remote island located in the southern Atlantic Ocean, an unknown melosiroid diatom species was studied using both light and scanning electron microscopy. It proved to be a new species described as Angusticopula rowlingiana sp. nov. and characterized by a large number of narrow copulae in the girdle, a marginal ring of small granules, very small pores covering the entire valve face and occasionally having internal valves.                The new species is compared with all Angusticopula species known worldwide and with several Melosira species showing a similar combination of characters. Short notes on its ecology are included.

scholarly journals Sunlight-absorbing aerosol amplifies the seasonal cycle in low cloud fraction over the southeast Atlantic

2021 ◽  
Author(s):  
Jianhao Zhang ◽  
Paquita Zuidema
Keyword(s):  
Boundary Layer ◽  
Seasonal Cycle ◽  
Large Scale ◽  
Cloud Fraction ◽  
Small Scale ◽  
Aerosol Cloud ◽  
Ascension Island ◽  
Tropospheric Aerosol ◽  
Low Cloud ◽  
Aerosol Cloud Interactions

Abstract. Many studies examining shortwave-absorbing aerosol-cloud interactions over the southeast Atlantic apply a seasonal averaging. This disregards a meteorology that raises the mean altitude of the smoke layer from July to October. This study details the month-by-month changes in cloud properties and the large-scale environment as a function of the biomass-burning aerosol loading at Ascension Island from July to October, based on measurements from Ascension Island (8º S, 14.5º W), satellite retrievals and reanalysis. In July and August, variability in the smoke loading predominantly occurs in the boundary layer. During both months, the low-cloud fraction is less and is increasingly cumuliform when more smoke is present, with the exception of a late morning boundary layer deepening that encourages a short-lived cloud development. The meteorology varies little, suggesting aerosol-cloud interactions consistent with a boundary-layer semi-direct effect can explain the cloudiness changes. September marks a transition month during which mid-latitude disturbances can intrude into the Atlantic subtropics, constraining the land-based anticyclonic circulation transporting free-tropospheric aerosol to closer to the coast. Stronger boundary layer winds help deepen, dry, and cool the boundary layer near the main stratocumulus deck compared to that on days with high smoke loadings, with stratocumulus reducing everywhere but at the northern deck edge. Longwave cooling rates generated by a sharp water vapor gradient at the aerosol layer top facilitates small-scale vertical mixing, and could help to maintain a better-mixed September free troposphere. The October meteorology is more singularly dependent on the strength of the free-tropospheric winds advecting aerosol offshore. Free-tropospheric aerosol is less, and moisture variability more, compared to September. Low-level clouds increase and are more stratiform, when the smoke loadings are higher. The increased free-tropospheric moisture can help sustain the clouds through reducing evaporative drying during cloud-top entrainment. Enhanced subsidence above the coastal upwelling region increasing cloud droplet number concentrations may further prolong cloud lifetime through microphysical interactions. Reduced subsidence underneath stronger free-tropospheric winds at Ascension supports slightly higher cloud tops during smokier conditions. Overall the monthly changes in the large-scale aerosol and moisture vertical structure act to amplify the seasonal cycle in low-cloud amount and morphology, raising a climate importance as cloudiness changes dominate changes in the top-of-atmosphere radiation budget.

scholarly journals STUDY ON URBAN RESIDUAL SPACE AS SOLUTIONS REVIEW FOR AREA PROBLEMS

SINERGI ◽  
2021 ◽  
Vol 25 (3) ◽  
pp. 245
Author(s):  
Diana Ayudya ◽  
Mona Anggiani
Keyword(s):  
Urban Areas ◽  
Open Space ◽  
Social Conditions ◽  
Urban Spaces ◽  
Vacant Land ◽  
Study Results ◽  
Spatial Use ◽  
Residual Space ◽  
Density Irregularity ◽  
The City

In cities, spaces were intentionally formed, planned, or unintentionally unplanned. Unlike planned spaces, unplanned spaces in urban areas eventually tend to cause problems for the area. These spaces were referred to as residual spaces, which were generally vacant land or open space in various urban spaces. Urban residual space was also commonly found in tertiary activity centers in big cities like Jakarta, one of which was in the trade and service area of the city. Residual space in such areas grew and developed due to dense activity within the area, resulting building density, irregularity in some spatial use and environmental degradation. Due such conditions, several questions are significant to be raised.  What are the typology, utilization, and its impacts on the area? Did it only cause a problem, or could it be a solution to problems within the area? This study aimed to examine the typology of residual space based on the shape, location, utilization, and impact of trade and service activities in South Jakarta, Kebayoran Lama area. The proposed approach used was a qualitative study of the residual spaces in predetermined trade and commercial areas. The study results of the physical, spatial, visual, and social conditions of urban residual space were explained descriptively to get a picture of the characteristics of the form, location, utilization, and impact on the area.

Sign in / Sign up

Export Citation Format

Share Document