Determination of Ku-band specific attenuation parameters based on measurements in the tropics

2013 ◽  
Author(s):  
A.F. Ismail ◽  
K. Badron ◽  
A.A.H. Yaccop ◽  
Y.D. Yao
Keyword(s):  
Specific Attenuation ◽  
The Tropics ◽  
Ku Band

scholarly journals Glacier Fluctuations and Climate in the Cordillera Blanca, Peru

1990 ◽  
Vol 14 ◽  
pp. 136-140 ◽  
Author(s):  
Georg Kaser ◽  
Alcides Ames ◽  
Marino Zamora
Keyword(s):  
Seasonal Temperature ◽  
Wet Season ◽  
Equilibrium Line Altitude ◽  
Cordillera Blanca ◽  
Covered Area ◽  
Recession Rates ◽  
Tropical Areas ◽  
Precipitation Records ◽  
The Tropics

With a total of 723 km2 of glaciers (1970) the Cordillera Blanca includes the largest glacier-covered area in the tropics. The climate is characterized by relatively large daily and small seasonal temperature variations as well as by a distinct succession between a dry (May–September) and a wet season (October–April). Since the early 1970s an ablation stake network has been installed on the tongues of the glaciers Uruashraju and Yanamarey. The determination of the equilibrium-line altitude at each end of a wet season was possible, showing a fair correlation with temperature, but not with the precipitation records of the nearby climatological station Querococha. Mean ablation rates at the lowest parts of the glacier tongues are markedly higher during the wet season than during the dry season. Reasons are presumably to be found in the seasonal variation of cloudiness and air moisture rates. Terminus variations of four glaciers in the Cordillera Blanca have been monitored since the early seventies, earlier positions are reconstructed back to 1948 by vertical air photographs. For the glaciers Uruashraju and Yanamarey the terminus positions of 1939 are known from an early map. The general retreat of glaciers in the Cordillera Blanca during the last five decades correlates with the global attitude of glaciers and especially with the attitude of glaciers in other tropical areas. Decreased recession rates with minor advances (1974–79 and 1985–86) are accompanied by lower annual temperatures and preceded and accompanied by years with relatively high annual precipitation sums.

scholarly journals DETERMINATION OF PLANTING PATTERN BASED ON WATER BALANCE ANALYSIS FOR FARMING PLANNING AT DRYLANDS IN THE TROPIC (A CASE STUDY IN GUNUNG MAS DISTRICT, CENTRAL KALIMANTAN PROVINCE, INDONESIA)

2021 ◽  
Vol 56 (4) ◽  
pp. 613-618
Author(s):  
Vera Amelia ◽  
Soaloon Sinaga ◽  
Andy Bhermana
Keyword(s):  
Water Balance ◽  
Water Availability ◽  
Critical Factor ◽  
Cropping Pattern ◽  
Horticultural Crops ◽  
Balance Analysis ◽  
Growth Requirement ◽  
The Tropics

The existence of water as a crop growth requirement is a prerequisite in tropical drylands. In addition, water balance, as an important part of climate change, is needed to be accessed under certain conditions. This study aimed to observe water availability and analyze water balance at drylands for farming planning purposes. The results of this study were then required to determine planting patterns and farming planning in the tropics, in which information related to hydrology is still lack. The Thornthwaite-Mather method approach was used in this study to analyze water balance in areas observed and. Because of its simplicity, this method can also be applied to areas with limited data. The water balance analysis that provides the information on water availability can be used as basic consideration for farming planning, especially at drylands in which water availability is a critical factor for farming activities. In tropical drylands, the cropping pattern of food crops – secondary crops – fallow – horticulture crops can be proposed within farming planning. Maize as a food crop can be planted for the early planting period in January, in which it can be harvested at the age of 80 days around March. In the following month, secondary crops such as soybeans can be planted and harvested at 135 days. Fallow periods during August and September, the lands cannot be optimally used because of water deficit. Entering the beginning of October, the land can be cultivated and prepared for the next crop, eggplant, as horticultural crops, harvested at 135 days in early February.

The apparent digestibility of crude protein by the ruminant: II. The general equation and some of its implications

1957 ◽  
Vol 48 (3) ◽  
pp. 379-383 ◽  
Author(s):  
M. H. French ◽  
J. Glover ◽  
D. W. Duthie
Keyword(s):  
General Equation ◽  
Crude Protein ◽  
Protein Digestibility ◽  
Practical Applications ◽  
Total Percentage ◽  
Large Bulk ◽  
Mixed Feeds ◽  
The Tropics ◽  
First Time

The general equation, y = 70 log x − 15, connecting y, the digestibility coefficient, to x, the percentage of crude protein in the dry matter of the feed of ruminants, which was proposed in an earlier paper, has been shown to fit all the directly determined world data for cattle, sheep and goats which have been published by Schneider (1947). It is applicable to rations composed of both single and mixed feeds for it is the total percentage of crude protein in the ration which determines its digestibility.The equation is of general application, irrespective of climate or feed, and for the first time a link is provided between the large bulk of data from temperate regions and those hitherto neglected and apparently aberrant data from the tropics and subtropics.The equation adequately explains a large part of the variability of results obtained by the ‘by difference’ method. In particular, attention is drawn to its value in explaining ‘associative effects’ in mixed feeds.It would seem to have several practical applications; one being the ready determination of the average digestibility of crude protein in rapidly growing grasses and herbages at different stages of development; another being the evaluation of average crude protein digestibility of single or compound feeds in those parts of the world where adequate facilities for digestibility studies are not available. It can also be used in computing maintenance and production rations for meat and milk.

scholarly journals Nitrogen Source Preference and Growth Carbon Costs of Leucaena leucocephala (Lam.) de Wit Saplings in South African Grassland Soils

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2242
Author(s):  
Nonkululeko Sithole ◽  
Zivanai Tsvuura ◽  
Kevin Kirkman ◽  
Anathi Magadlela
Keyword(s):  
South African ◽  
Leucaena Leucocephala ◽  
Biomass Accumulation ◽  
N Nutrition ◽  
Climatic Regions ◽  
Carbon Costs ◽  
Kwazulu Natal ◽  
Microbial Symbiosis ◽  
The Tropics

Leucaena leucocephala (Fabaceae) is native to Central America and has invaded many climatic regions of the tropics. In South Africa, the species is categorized as an emerging or incipient weed used as fodder, timber, firewood and in erosion control on degraded habitats. The species is common along the eastern subtropical regions of KwaZulu-Natal (KZN) Province, where it invades grasslands, savannas and edges of forests. Soils of these ecosystems are characterized as nutrient deficient and acidic. Using a pot trial, we determined the effects of the nutrient addition treatments on microbial symbiosis, N nutrition and biomass accumulation of L. leucocephala under greenhouse conditions. After 180 days of growth, plants were harvested, and their utilization of N derived from the atmosphere and from the soil was quantified through determination of δ15N values. L. leucocephala maintained growth and N nutrition by relying on both atmospheric- and soil-derived N across all soil treatments. The NDFA was significantly higher in high P (N1 + P, N2 + P and N3 + P) soils. L. leucocephala was able to nodulate with intermediate and fast-growing strains from the Mesorhizobium and Rhizobium genus in N2 + P grown plants. This shows that L. leucocephala possesses traits that are successful in acquiring nutrients, especially in nutrient limited conditions, by establishing plant symbiosis with multiple bacteria and relying on extracting N from the soil and from the atmosphere through the symbiosis.

scholarly journals UJI AKTIVITAS TABIR SURYA DAN ANTIOKSIDAN EKSTRAK ETANOL DAUN SUNGKAI (Perenema canescens Jack)

2021 ◽  
Vol 6 (2) ◽  
pp. 322-330
Author(s):  
Fadlilaturrahmah Fadlilaturrahmah ◽  
◽  
Amalia Khairunnisa ◽  
Aditya MP Putra ◽  
Ivanna Sinta
Keyword(s):  
Antioxidant Activity ◽  
Plant Extract ◽  
Inhibitory Concentration ◽  
Premature Aging ◽  
Cosmetic Products ◽  
Natural Plant ◽  
Synthetic Chemicals ◽  
Dpph Method ◽  
The Tropics

Indonesia, which is located in the tropics, causes people's skin to easily experience premature aging and tan. Most of these cosmetic products contain dangerous synthetic chemicals. For this reason, cosmetic products with natural active ingredients or phytocosmetics that are effective and safe to use need to be developed. One of the typical natural plant plants from South Kalimantan that has the potential to be developed as a cosmetic preparation is Sungkai (Peronema canescens Jack). The aim of the study was to determine the antioxidant activity and sunscreen activity of Sungkai leaves. The method used for the determination of antioxidant activity is the DPPH method using a uv-vis spectrophotometer and for the determination of sunscreen activity using a uv-vis spectrophotometer. The results showed that the P. canescens plant extract contained anthraquinones, flavonoids, saponins, tannins, and phenols. P.canescens plants have an Inhibitory Concentration 50 (IC50 ) of 42.219±19.440 ppm and have sunscreen activity with spf (Sun Protecting Factor) values ??with concentrations of 600 ppm, 400 ppm, 200 respectively as follows: 24±0.31; 16±0.34; and 8±0.3. The conclusion of this study Sungkai (Peronema canescens Jack) has antioxidant activity and has sunscreen activity so that it has the potential to be developed into natural skin care.

scholarly journals Support vector machine tropical wind speed retrieval in the presence of rain for Ku-band wind scatterometry

2021 ◽  
Author(s):  
Xingou Xu ◽  
Ad Stoffelen
Keyword(s):  
Machine Learning ◽  
Support Vector Machine ◽  
Wind Speed ◽  
Error Variance ◽  
Complex Problem ◽  
Support Vector ◽  
Tropical Regions ◽  
Wind Retrieval ◽  
Ku Band

Abstract. Wind retrieval parameters, i.e., quality indicators and the 2DVAR analysis speeds, are explored with the aim to improve wind speed retrieval during rain for tropical regions. We apply the well-researched support vector machine (SVM) method in machine learning (ML) to solve this complex problem in a data-orientated regression. To guarantee the effectiveness of SVM, the inputs are extensively analysed to evaluate their appropriateness for this problem, before the results are produced. Subsequently, triple collocation shows that the similarity of the resolved Ku-band (OSCAT-2) wind speed in rain is better than the 2DVAR speed, with respect to the collocated C-band (ASCAT) speed, which is much less affected by rain. The comparisons between distributions and differences between data of rain-contaminated winds, corrected winds and good quality C-band winds, illustrate that the rain-distorted wind distributions become more nominal with SVM, hence eliminating rain-induced biases and error variance. Further confirmation is obtained from a case with synchronous Himawari-8 observation indicating rain (clouds) in the scene. Furthermore, the determination of simultaneous rain rate is attempted to retrieve both wind and rain. Although, additional observations or higher resolution may be required to better assess the accuracy of the wind and rain retrievals, the Machine Learning (ML) results demonstrate benefits of such methodology in geophysical retrieval and nowcasting applications.

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