scholarly journals The level variability, thermal structure and currents in Lake Chapala, Mexico

2016 ◽  
Vol 55 (3) ◽  
Author(s):  
David Ávalos-Cueva ◽  
Anatoliy Filonov ◽  
Iryna Tereshchenko ◽  
César Monzón ◽  
Diego Pantoja-González ◽  
...  
Keyword(s):  
Cross Sections ◽  
Thermal Structure ◽  
The North ◽  
Lake Chapala ◽  
Four Seasons ◽  
Anticyclonic Gyre ◽  
Dry Seasons ◽  
North And South ◽  
Good Agreement ◽  
Wet And Dry Seasons

Measurements of temperature, currents and lake level taken in 2005-2014 are analyzed and discussed. Moored measurements of temperature and level in the northern part of the lake reveal the presence of seiches oscillations of the first and second modes, with periods of 5.7 and 2.8 hours, and amplitudes of 15.4 and 2.1 mm. In 2006 four temperature cross-sections were carried out in the study area. The obtained data reveal that in all four seasons of the year the temperatures averaged over the north and south coastal areas differ by 2-3°C. The lake currents were simulated using the HAMSOM 2-D hydrodynamic model both for wet and dry seasons. The model results are in good agreement with the ADCP data. The presence of an anticyclonic gyre, 10-12 km in diameter, in the central part of the lake in both seasons is revealed. In particular, the summer 2014 data provide evidence of the gyre and its impact on the spatial distribution of temperature in the lake.

scholarly journals Thermal structure and circulation in Lake Chapala, Mexico

2016 ◽  
Vol 75 (s1) ◽  
Author(s):  
David Avalos-Cueva ◽  
Anatoliy Filonov ◽  
Iryna Tereshchenko ◽  
César O. Monzón ◽  
Federico Á. Velázquez-Muñoz
Keyword(s):  
Thermal Structure ◽  
Acoustic Doppler Current Profiler ◽  
Dry Season ◽  
Spatial Average ◽  
Average Temperature ◽  
Lake Chapala ◽  
Anticyclonic Gyre ◽  
Current Profiler ◽  
Adcp Measurements ◽  
Good Agreement

<p>This study analyzed and discussed the instrumental measurements of temperature and currents made on January 10, 2007, in Lake Chapala. We received new data on the formation of the thermocline. It is shown that the thermocline of the lake is formed only in the daytime and in a top-heated 0.5-1.0 m layer. The vertical temperature gradient reaches 2.5°C in the first meter, and the spatial average temperature across the lake showed that the northern end of the lake is, on average, 1°C warmer than the southern end. We numerically modelled the currents in the lake for the dry season using the HAMSOM 2D hydrodynamic model. The simulation results are in good agreement with the acoustic Doppler current profiler ADCP measurements. In the dry season, two gyres were found: a cyclonic gyre in the eastern part and an anticyclonic gyre in the western part.</p>

scholarly journals Long-term changes in rainfall and tropical cyclone activity over South and Southeast Asia

2011 ◽  
Vol 30 ◽  
pp. 17-22 ◽  
Author(s):  
H. G. Takahashi
Keyword(s):  
Tropical Cyclone ◽  
Southeast Asia ◽  
North Indian Ocean ◽  
Cyclone Activity ◽  
The North ◽  
South And Southeast Asia ◽  
Long Term Changes ◽  
Dry Seasons ◽  
Wet And Dry Seasons

Abstract. Long-term changes in rainfall and associated tropical cyclone (TC) activity in transition seasons between the wet and dry seasons in South and Southeast Asia, namely boreal spring and fall, were examined, using gridded rainfall, TC tracks, and reanalysis datasets, the focus of discussion being the long-term changes in coastal regions. It was found that long-term changes in rainfall during the transition seasons in South and Southeast Asia were closely associated with those in TC activity over the north Indian Ocean and South China Sea. Rainfall in May increased in the last 40 years over and around Myanmar, which indicates an earlier monsoon onset over the western Indochina Peninsula. Rainfall over and around northern Vietnam also increased in the last 40 years during October, which is known as the monsoon retreat period. These increases were associated with the long-term changes in TC activity. Furthermore, although linear trends have been previously suggested, monotonically increasing or decreasing trends in these long-term changes were not found over the last 60 years.

scholarly journals The seasonal diet of Aequidens tetramerus (Cichlidae) in a small forest stream in the Machado River basin, Rondônia, Brazil

2015 ◽  
Vol 45 (4) ◽  
pp. 365-372 ◽  
Author(s):  
Igor David da COSTA ◽  
Maiza Oliveira SOARES
Keyword(s):  
Drainage Basin ◽  
Temporal Variations ◽  
Trophic Relationships ◽  
Animal Origin ◽  
Wet Season ◽  
The North ◽  
Forest Stream ◽  
Dry Seasons ◽  
Terrestrial Insects ◽  
Wet And Dry Seasons

Trophic relationships in fish communities are affected by the availability of resources, which in turn is affected by spatial and temporal variations throughout the year. The aims of this study were to characterize the diet of A. tetramerus in a streamlet in the north of Brazil and compare its composition in different hydrological seasons (wet and dry seasons). Collections were performed every two months from October 2011 to September 2012 with the aid of seine nets, hand net and fishing traps in the streamlet located in the Machado River drainage basin in the Rondônia state. Most of the specimens collected were quite small (< 40 mm) and had empty stomachs. Our results showed that A. tetramerus feeds on a wide variety of items of plant origin, such as algae, seeds and leaves, as well as items of animal origin, including bryozoans, crustaceans, fish scales, terrestrial insects and detritus. The data also indicated higher consumption of aquatic insects than other food items, suggesting a primarily insect-based diet. Items of plant and allochthonous origin were consumed more in the wet season than in the dry season, but there were no seasonal differences in the consumption of animal and autochthonous items.

Observations on The bionomics ofAnopheles darlingiRoot (Diptera: Culicidae) from Brazil

1980 ◽  
Vol 70 (4) ◽  
pp. 685-692 ◽  
Author(s):  
J. D. Charlwood
Keyword(s):  
Malaria Vector ◽  
Rainy Season ◽  
Physiological Age ◽  
Adult Survival ◽  
Anopheles Darlingi ◽  
Mato Grosso ◽  
The North ◽  
Dry Seasons ◽  
The Village ◽  
Wet And Dry Seasons

AbstractThe physiological age-structure of populations of the malaria vectorAnopheles darlingiRoot, collected biting man, was determined from collections made from March to June 1979 at the end of the rainy season in the village of Aripuanã, Mato Grosso, Brazil. The number of mosquitoes biting increased during the transition between the wet and dry seasons, but adult survival remained low at all times. Only seven of 1596 females dissected had laid eggs four or more times, and thus the proportion of females that could be potentially infective with malaria sporozoites was 0.4%. The mosquitoes rested in the vicinity of the host for periods of up to 10 min before biting. The results are compared to those obtained during a study onA. darlingion the Manaus-Boa Vista Highway, 1000 km to the north. In this area, peak numbers were collected at the beginning of the rainy season and adult survival was longer than at Aripuanã.

117. An Unusual Variation in the Butterfat Content of Milk

1935 ◽  
Vol 6 (3) ◽  
pp. 353-362 ◽  
Author(s):  
K. Hartley ◽  
D. W. H. Baker
Keyword(s):  
Dry Season ◽  
Wet Season ◽  
Four Seasons ◽  
Dry Seasons ◽  
The Government ◽  
Wet And Dry Seasons

1. Some account has been given of the cattle kept on the Government Farm at Samaru, Zaria, and of their management in the wet and dry seasons.2. Figures extending over four seasons have been presented to show thatthe butterfat content of the milk produced on this farm is consistently higher in the morning than in the evening during the wet season, and that the reverseis true during the dry season.3. The relative quantity of milk produced in the evening during the dry season is slightly less than during the wet season, but this difference is quiteinadequate to explain the change in the percentages of butterfat.4. Some evidence is offered that this change in butterfat content is directly due to the marked climatic differences between the two seasons, and that it cannot be controlled by altering the diet of the cattle.

The Pleistocene Succession in the Lower parts of the Thames Valley

1936 ◽  
Vol 2 (1-2) ◽  
pp. 52-76 ◽  
Author(s):  
W. B. R. King ◽  
K. P. Oakley
Keyword(s):  
Cross Sections ◽  
Present Knowledge ◽  
Present Communication ◽  
River Level ◽  
Main Valley ◽  
The North ◽  
Composite Section ◽  
The One ◽  
North And South ◽  
As If

The object of the present communication is to demonstrate the relationships which, in the light of present knowledge, appear to exist between the various Pleistocene and Holocene deposits in the Lower and Middle Thames Valley. For this purpose two cross-sections of the valley have been drawn indicating the relative positions of the deposits which occur at various localities as though they were all present in two localities, one in the Lower, and one in the Middle Thames.As many of the more important deposits in the Lower Thames are represented to the north and south of the river in the Dartford area, we have drawn the one section as if our ideal locality occurred in that neighbourhood. In this section, therefore, the relative altitudes of the various beds above and below present river level are those which are found in that part of the Thames basin. In tributary valleys, or in other parts of the main valley these altitudes are not of course necessarily maintained. In cases where deposits belonging to a particular stage have not been preserved in the Dartford area, but occur in a neighbouring part of the valley, or in a tributary valley, their position in the composite section has been roughly gauged by a process of extrapolation. Similarly when dealing with the Middle Thames, we have drawn our ideal section as though all the deposits occurred in one section of the valley in the neighbourhood of Iver.

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