scholarly journals Some problems connected with evaporation from large expanses of water

1921 ◽  
Vol 99 (701) ◽  
pp. 472-490 ◽  
Keyword(s):  
Vapour Pressure ◽  
Water Surface ◽  
Complex Problem ◽  
Dew Point ◽  
Ice Age ◽  
Trade Wind ◽  
Tropical Regions ◽  
The North ◽  
Rate Of Evaporation ◽  
Large Stretch

1. The water which falls as rain is originally evaporated either from land surfaces, forests, etc., or from the oceans, in particular from the latter. It is therefore of importance to ascertain how the evaporated water distributes itself in an atmospheric current during its progress across a water surface, and, further, to investigate the relation between the length of the path over the water surface and the amount of water thereby rendered available. In this paper, these problems are treated for the case of a current of air of uniform speed moving over a water surface of uniform temperature. An empirical formula is employed to represent the rate of evaporation from each element of the water surface, and account is taken of the stirring upwards of the evaporated water by the agency of turbulence, assuming the latter to be uniformly distributed throughout the current of air. The results obtained would find application, for example, in discussing problems connected with evaporation in the trade wind zones, or from inland seas and lakes, or, in particular, from the North Sea, winds from which frequently bring much cloud and quite appreciable rainfall to the eastern coasts of Great Britain and the northern coasts of France. All the constants occurring in the formulae obtained are known, either accurately or approximately, and, accordingly, the order of magnitude of the evaporation from a given stretch of water, under assigned conditions, can be estimated. What is also of importance, is the comparison of the amount of water evaporated from a given area or of the distribution of water vapour in the air above it, under one set of conditions, with those under a different set. Of particular interest is the effect of varying the speed of the air. 2. The suggestion which led to the present investigation is contained in a paper on “ The Meteorological Conditions of an Ice Sheet and their bearing on the Desiccation of the Globe.” The author of that paper, in considering the evaporation in tropical and sub-tropical regions during the Quaternary Ice Age as compared with that at the present time, has occasion to compare the rate of evaporation from large expanses of water under different conditions as to wind and surface temperature, and Lt. -Col. E. Gold, in the discussion, emphasises the fact that this is in reality a very complex problem for the formula used (quoted below, p. 474) for the rate of evaporation from an element of the surface, involves the vapour pressure at the dew point of the air “ near ” the surface. Now this vapour pressure varies from point to point along the current of air which is traversing the water, so that an integration is necessary in order to obtain the rate of evaporation from a large stretch of water, and, further, the vapour pressure at any point depends on the speed with which the air has reached that point, which complicates the problem of comparing the evaporation under different wind conditions.

Peculiarities of the course of the postpartum period in domestic reindeer females, its morphophysiology and behavioral reactions in the North-East of Russia (Republic of Sakha)

2020 ◽  
pp. 99-105
Author(s):  
V. Fedorov ◽  
E. Sleptsov ◽  
K. Plemyashov
Keyword(s):  
Postpartum Period ◽  
Reproductive Function ◽  
Complex Problem ◽  
Climatic Conditions ◽  
Taiga Zone ◽  
Behavioral Reactions ◽  
North East ◽  
The North ◽  
The Republic ◽  
Mountain Taiga

A growth in the number of deer and an increase in their productivity are closely related to the solution of the complex problem of reproduction and rational use of deer females. Significant damage to reindeer husbandry is caused by the barrenness of northern domestic deer, the level of which has been quite high in recent years. So, in the Republic of Sakha, on 01.01.2020, the number of domesticated reindeer was 152,068, of which female deer and heifers — 71,818, offspring per 100 females — 59, business yield amounted to 52 fawns per 100 females. The causes of infertility are very diverse, as the natural and climatic conditions of the breeding zones have a significant influence on the reproductive function of reindeer. In Yakutia, the main population of northern domestic deer is bred in mountain taiga and tundra natural-climatic zones, so there are about 55 thousand deer in the mountain taiga zone and more than 65 thousand deer in the tundra zone. In this regard, the study of the peculiarities of the postpartum period course in domestic reindeer females, its morphophysiology, and behavioral reactions depending on the natural and climatic conditions of breeding is of great importance.

7000 years of paleostorm activity in the NW Mediterranean Sea in response to Holocene climate events

2012 ◽  
Vol 77 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Pierre Sabatier ◽  
Laurent Dezileau ◽  
Christophe Colin ◽  
Louis Briqueu ◽  
Frédéric Bouchette ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
North Atlantic ◽  
Clay Mineralogy ◽  
Mediterranean Coast ◽  
Ice Age ◽  
Storm Activity ◽  
The North ◽  
Nw Mediterranean ◽  
The North Atlantic ◽  
Nw Mediterranean Sea

A high-resolution record of paleostorm events along the French Mediterranean coast over the past 7000 years was established from a lagoonal sediment core in the Gulf of Lions. Integrating grain size, faunal analysis, clay mineralogy and geochemistry data with a chronology derived from radiocarbon dating, we recorded seven periods of increased storm activity at 6300–6100, 5650–5400, 4400–4050, 3650–3200, 2800–2600, 1950–1400 and 400–50 cal yr BP (in the Little Ice Age). In contrast, our results show that the Medieval Climate Anomaly (1150–650 cal yr BP) was characterised by low storm activity.The evidence for high storm activity in the NW Mediterranean Sea is in agreement with the changes in coastal hydrodynamics observed over the Eastern North Atlantic and seems to correspond to Holocene cooling in the North Atlantic. Periods of low SSTs there may have led to a stronger meridional temperature gradient and a southward migration of the westerlies. We hypothesise that the increase in storm activity during Holocene cold events over the North Atlantic and Mediterranean regions was probably due to an increase in the thermal gradient that led to an enhanced lower tropospheric baroclinicity over a large Central Atlantic-European domain.

scholarly journals Performance Study of a Floricultural Greenhouse Surrounded by Shallow Water Ponds

2017 ◽  
Vol 6 (2) ◽  
pp. 137
Author(s):  
Debajit Misra ◽  
Sudip Ghosh
Keyword(s):  
Shallow Water ◽  
Water Surface ◽  
Natural Ventilation ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Free Water ◽  
Weather Data ◽  
Ventilation Mode ◽  
Performance Study ◽  
Tropical Regions

In the present paper, an innovative low energy-intensive evaporative cooling system has been proposed for greenhouse application in near-tropical regions dominated by hot climate. The system can operate under dual- ventilation mode to maintain a favourable microclimate inside the greenhouse. A single ridge type un-even span greenhouse has been considered, targeting a few species of Indian tropical flowers. The greenhouse has a continuous roof vent as well as adjustable side vents and is equipped with exhaust fans on top and roll-up curtains on the sides. The greenhouse is surrounded by shallow water ponds outside its longitudinal walls and evaporative surfaces partially cover the free water surface. Inside the pond, low cost evaporative surfaces are so placed that they form air channels.  Thus, outside air flows through the channels formed by the wetted surfaces over the water surface and undergoes evaporative cooling before entering the greenhouse. A simplified theoretical model has been presented in this paper to predict the inside greenhouse air temperature while ambient weather data are used as model inputs. The study reveals that during average radiation periods, the greenhouse can depends solely on natural ventilation and during peak radiation hours fan-induced ventilation is needed to maintain the required level of temperature. It is seen that under dual-ventilation mode greenhouse, temperature can be kept 3-6 oC lower than ambient temperature when saturation effectiveness is 0.7 and with 75% shading. Keywords: Greenhouse, Evaporative Cooling, Ventilation, Saturation Effectiveness, Wetted SurfaceArticle History: Received February 25th 2017; Received in revised form April 14th 2017; Accepted May 4th 2017; Available onlineHow to Cite This Article: Misra, D. and Ghosh, S., (2017) Performance Study of a Floricultural Greenhouse Surrounded by Shallow Water Ponds. International Journal of Renewable Energy Develeopment, 6(2), 137-144.https://doi.org/10.14710/ijred.6.2.137-144

scholarly journals Multidecadal to millennial marine climate oscillations across the Denmark Strait (~ 66° N) over the last 2000 cal yr BP

2014 ◽  
Vol 10 (1) ◽  
pp. 325-343 ◽  
Author(s):  
J. T. Andrews ◽  
A. E. Jennings
Keyword(s):  
North Atlantic ◽  
Low Frequency ◽  
Atlantic Water ◽  
Ice Age ◽  
The North ◽  
Denmark Strait ◽  
Water Stratification ◽  
The North Atlantic Oscillation ◽  
Frequency Variations ◽  
Marine Climate

Abstract. In the area of Denmark Strait (~66° N), the two modes of the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) are expressed in changes of the northward flux of Atlantic water and the southward advection of polar water in the East Iceland current. Proxies from marine cores along an environmental gradient from extensive to little or no drift ice, capture low frequency variations over the last 2000 cal yr BP. Key proxies are the weight% of calcite, a measure of surface water stratification and nutrient supply, the weight% of quartz, a measure of drift ice transport, and grain size. Records from Nansen and Kangerlussuaq fjords show variable ice-rafted debris (IRD) records but have distinct mineralogy associated with differences in the fjord catchment bedrock. A comparison between cores on either side of the Denmark Strait (MD99-2322 and MD99-2269) show a remarkable millennial-scale similarity in the trends of the weight% of calcite with a trough reached during the Little Ice Age. However, the quartz records from these two sites are quite different. The calcite records from the Denmark Strait parallel the 2000 yr Arctic summer-temperature reconstructions; analysis of the detrended calcite and quartz data reveal significant multi-decadal–century periodicities superimposed on a major environmental shift occurring ca. 1450 AD.

RATE OF EVAPORATION FROM A FREE-WATER SURFACE AS INFLUENCED BY EXPOSURE

1961 ◽  
Vol 41 (1) ◽  
pp. 199-203 ◽  
Author(s):  
A. C. Carder
Keyword(s):  
Water Surface ◽  
Meteorological Factors ◽  
Free Water ◽  
Water Evaporation ◽  
High Wind ◽  
Progressive Decrease ◽  
Factors Affecting ◽  
Wind Velocities ◽  
Rate Of Evaporation ◽  
Low Rate

In a 3-year free-water evaporation study, an evaporimeter tank in the open field lost 34.5 per cent more water than a tank sheltered by buildings and trees. Meteorological factors responsible for this difference appear to be high wind velocities and long daily periods of sunshine. Changes in temperature regime had no effect.Difference in evaporation from the two tanks led to examination of data obtained over 35 years from the sheltered tank. It was found that, although there was a progressive decrease in amount of evaporation over the years from this tank, rainfall at the same time had increased and that the effect of this increase on evaporation was roughly equal to that of all other factors affecting evaporation, such as a change in exposure, etc. Thus, the comparatively low rate of evaporation from the sheltered tank was undoubtedly due in part to the proximity of buildings and trees which had been established.

scholarly journals Climatic variability and human impact during the last 2000 years in western Mesoamerica: evidence of late Classic (AD 600–900) and Little Ice Age drought events

2015 ◽  
Vol 11 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
A. Rodríguez-Ramírez ◽  
M. Caballero ◽  
P. Roy ◽  
B. Ortega ◽  
G. Vázquez-Castro ◽  
...  
Keyword(s):  
Human Impact ◽  
Little Ice Age ◽  
Climatic Variability ◽  
Seasonal Migration ◽  
Ice Age ◽  
Cultural Tradition ◽  
Late Classic ◽  
High Pressure Cell ◽  
Western Mexico ◽  
The North

Abstract. We present results of analysis of biological (diatoms and ostracodes) and non-biological (Ti, Ca / Ti, total inorganic carbon, magnetic susceptibility) variables from an 8.8 m long, high-resolution (~ 20 yr sample−1) laminated sediment sequence from Lake Santa María del Oro (SMO), western Mexico. This lake lies at a sensitive location between the dry climates of northern Mexico, under the influence of the North Pacific subtropical high-pressure cell and the moister climates of central Mexico, under the influence of the seasonal migration of the intertropical convergence zone and the North American monsoon (NAM). The sequence covers the last 2000 years and provides evidence of two periods of human impact in the catchment, shown by increases in the diatom Achnanthidium minutissimum. The first from AD 100 to 400 (Early Classic) is related to the shaft and chamber tombs cultural tradition in western Mexico, and the second is related to Post-Classic occupation from AD 1100 to 1300. Both periods correspond to relatively wet conditions. Three dry intervals are identified from increased carbonate and the presence of ostracodes and aerophilous Eolimna minima. The first, from AD 500 to 1000 (most intense during the late Classic, from AD 600 to 800), correlates with the end of the shaft and chamber tradition in western Mexico after ca. AD 600. This late Classic dry period is the most important climatic signal in the Mesoamerican region during the last 2000 years, and has been recorded at several sites from Yucatan to the Pacific coast. In the Yucatan area, this dry interval has been related with the demise of the Maya culture at the end of the Classic (AD 850 to 950). The last two dry events (AD 1400 to 1550 and 1690 to 1770) correspond with the onset of, and the late, Little Ice Age, and follow largely the Spörer and Maunder minima in solar radiation. The first of these intervals (AD 1400 to 1550) shows the most intense signal over western Mexico; however this pattern is different at other sites. Dry/wet intervals in the SMO record are related with lower/higher intensity of the NAM over this region, respectively.

scholarly journals Bunker Cave stalagmites: an archive for central European Holocene climate variability

2012 ◽  
Vol 8 (3) ◽  
pp. 1687-1720 ◽  
Author(s):  
J. Fohlmeister ◽  
A. Schröder-Ritzrau ◽  
D. Scholz ◽  
C. Spötl ◽  
D. F. C. Riechelmann ◽  
...  
Keyword(s):  
Climate Variability ◽  
North Atlantic ◽  
Little Ice Age ◽  
Ice Age ◽  
Holocene Climate ◽  
Central European ◽  
The North ◽  
The North Atlantic ◽  
Meteoric Precipitation ◽  
Precipitation And Temperature

Abstract. Holocene climate was characterised by variability on multi-centennial to multi-decadal time scales. In central Europe, these fluctuations were most pronounced during winter. Here we present a new record of past winter climate variability for the last 10.8 ka based on four speleothems from Bunker Cave, Western Germany. Due to its central European location, the cave site is particularly well suited to record changes in precipitation and temperature in response to changes in the North Atlantic realm. We present high resolution records of δ18O, δ13C values and Mg/Ca ratios. We attribute changes in the Mg/Ca ratio to variations in the meteoric precipitation. The stable C isotope composition of the speleothems most likely reflects changes in vegetation and precipitation and variations in the δ18O signal are interpreted as variations in meteoric precipitation and temperature. We found cold and dry periods between 9 and 7 ka, 6.5 and 5.5 ka, 4 and 3 ka as well as between 0.7 to 0.2 ka. The proxy signals in our stalagmites compare well with other isotope records and, thus, seem representative for central European Holocene climate variability. The prominent 8.2 ka event and the Little Ice Age cold events are both recorded in the Bunker cave record. However, these events show a contrasting relationship between climate and δ18O, which is explained by different causes underlying the two climate anomalies. Whereas the Little Ice Age is attributed to a pronounced negative phase of the North Atlantic Oscillation, the 8.2 ka event was triggered by cooler conditions in the North Atlantic due to a slowdown of the Thermohaline Circulation.

scholarly journals A high-resolution model of the 100 ka ice-age cycle

1997 ◽  
Vol 25 ◽  
pp. 58-65 ◽  
Author(s):  
L. Tarasov ◽  
W. R. Peltier
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Relaxation Times ◽  
Ice Age ◽  
Adjustment Process ◽  
Glacial Cycle ◽  
Ice Dynamics ◽  
Last Glacial ◽  
The North ◽  
The Last Glacial

Significant improvements to the representation of climate forcing and mass-balance response in a coupled two-dimensional global energy balance climate model (EBM) and vertically integrated ice-sheet model (ISM) have led to the prediction of an ice-volume chronology for the most recent ice-age cycle of the Northern Hemisphere that is close to that inferred from the geological record. Most significant is that full glacial termination is delivered by the model without the need for new physical ingredients. In addition, a relatively close match is achieved between the Last Glacial Maximum (LGM) model ice topography and that of the recently-described ICE-4G reconstruction. These results suggest that large-scale climate system reorganization is not required to explain the main variations of the North American (NA) ice sheets over the last glacial cycle. Lack of sea-ice and marine-ice dynamics in the model leaves the situation over the Eurasian (EA) sector much more uncertain.The incorporation of a gravitationally self-consistent description of the glacial isostatic adjustment process demonstrates that the NA and EA bedrock responses can be adequately represented by simpler damped-relaxation models with characteristic time-scales of 3–5ka and 5 ka, respectively. These relaxation times agree with those independently inferred on the basis of postglacial relative sea-level histories.

scholarly journals CARTOGRAFIAS DA VITICULTURA EM MINAS GERAIS: da gênese no Sul à expansão para o Norte

2021 ◽  
Vol 7 (20) ◽  
pp. 202106
Author(s):  
Marcelo Cervo Chelotti ◽  
Rosa Maria Vieira Medeiros
Keyword(s):  
Spatial Pattern ◽  
Agricultural Research ◽  
Secondary Data ◽  
Minas Gerais ◽  
The State ◽  
The South ◽  
New Paradigm ◽  
Tropical Regions ◽  
The North ◽  
Agricultural Census

CARTOGRAPHS OF VITICULTURE IN MINAS GERAIS: from South genesis to North expansionCARTOGRAFÍAS DE LA VITICULTURA EN MINAS GERAIS: de la génesis en el Sur a la expansión al NorteRESUMOO presente artigo tem como objetivo analisar a reorientação no deslocamento do padrão espacial do cultivo de uvas no estado de Minas Gerais, originalmente localizado no Sul, mas expandiu-se para o norte mineiro nas últimas décadas. Os procedimentos metodológicos centraram-se na revisão de literatura sobre a viticultura no Brasil, e na coleta em dados secundários na Pesquisa Agrícola Municipal/PAM/IBGE, nos Censos Agropecuários do IBGE, além do Banco de Dados de Uva, Vinho e Derivados/VITIBRASIL. Os mapas temáticos demonstraram a dinâmica da viticultura em Minas Gerais, evidenciando uma mudança no padrão espacial, ou seja, historicamente concentrada no sul do estado, mas verificamos no pós-1990 uma expansão geográfica para o norte, principalmente em direção ao Cerrado e vale do Rio São Francisco. O papel desempenhado pela pesquisa, na busca de novas técnicas para a viticultura em regiões tropicais, tem uma grande centralidade nesse processo, uma vez que estamos diante de um novo paradigma para a produção de uvas e vinhos.Palavras-chave: Viticultura; Regionalização; Geografia do Vinho; Minas Gerais.ABSTRACTThis article has the goal to analyze the reorientation in the displacement of the spatial pattern of grape cultivation in the state of Minas Gerais, originally located in the south, but has expanded to the north of Minas Gerais in recent decades. The methodological procedures focused on the literature review on viticulture in Brazil, and the collection of secondary data from the Municipal Agricultural Research/PAM/IBGE, the IBGE Agricultural Census, and the Grape, Wine and Derivatives Database/VITIBRASIL. Thematic maps showed the dynamics of viticulture in Minas Gerais, showing a change in the spatial pattern, that is, historically concentrated in the south of the state. Sao Francisco River. The role played by the research in the search for new techniques for viticulture in tropical regions has a great centrality in this process, since we are facing a new paradigm for the production of grapes and wines.Keywords: Viticulture; Regionalization; Wine Geography; Minas Gerais.RESUMENEl presente artículo tiene como objetivo analizar la reorientación en el desplazamiento del patrón espacial del cultivo de la uva en el estado de Minas Gerais, originalmente ubicado en el sur, pero se ha expandido al norte de Minas Gerais en las últimas décadas. Los procedimientos metodológicos se centraron en la revisión de la literatura sobre viticultura en Brasil, y en la recopilación de datos secundarios en la Investigación Agrícola Municipal/PAM/IBGE, en los Censos Agrícolas del IBGE, además de la Base de Datos de Uva, Vino y Derivados/VITIBRASIL. Los mapas temáticos demostraron la dinámica de la viticultura en Minas Gerais, mostrando un cambio en el patrón espacial, es decir, históricamente concentrado en el sur del estado, pero en la década de 1990 verificamos una expansión geográfica hacia el norte, principalmente hacia el Cerrado y Vale do Río São Francisco El papel desempeñado por la investigación, en la búsqueda de nuevas técnicas para la viticultura en las regiones tropicales, tiene una gran centralidad en este proceso, ya que nos enfrentamos a un nuevo paradigma para la producción de uvas y vinos.Palabras-clave: Viticultura; Regionalización; Geografía del Vino; Minas Gerais.

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