High-Altitude Experimental Test of the Wind-Wave Interaction Models

2021 ◽  
Author(s):  
Alexander Babanin ◽  
Eduardo Palenque
Keyword(s):  
Wave Interaction ◽  
Sandy Beaches ◽  
Dry Season ◽  
Daily Temperature ◽  
Temperature Cycle ◽  
The South ◽  
The North ◽  
Large Water ◽  
Empirical Coefficients ◽  
The Waves

<p>We present the idea to experimentaly test the empirical models used in fluid mechanics. The models consider that the waves develop due the wind energy trasferred from the air to the urface of the water. However, all of those models were validated considering data at sea level, with effectively fixed air density. Here we propose to test the adjustment of the empirical coefficients studying the waves generated in Lake Titikaka, which is located at an altitute high enough (3800 m) to have a reduced atmospheric pressure. Lake Titikaka is located in the North side of the Altiplano (high plateu) in South America. It is shared between Bolivia and Peru, and it is, by far, the largest water body in the region, and at such altitudes in general. So it becomes a dominant geographical and climatic unit in the South American Altiplano, which has a desert–like climate, with monsoon-type rainy season (November to February) and a long dry season (March to October). During the dry season (local winter) the daily temperature cycle goes from maxima around 15 °C (past noon) to freezing minima near -5 °C (before dawn). This temperature span is larger than the seasonal difference, around 5 °C, between summer and winter. Due to its large water mass, the Lake hampers the temperature variations and avoids the freezing of both the lake itself and its shores. The daily temperature fluctuations cause also a daily wind-intensity cycle, with maxima just before the sunset. Lake Titikaka has an alongated shape with a long axis of 120 km in the NW-SE direction, and its short axis of 50 km in the NE-SW direction; with a large peninsula on the South shore (Copacabana). This size, plus deep waters (in excess of 250 m, pelagic condition) allows development of extnsive waves produced by the surface winds, coming predominantly from the North. The shores of Lake Titikaka have several geographical features, among others: delta rivers, sandy beaches and rock cliffs. The (“main”) study site is located in the large portion of the lake, near a mid-point between Santiago de Huata and the Isla de la Luna (Moon Island) as far possible from the shores.</p>

Third report on Glossina investigations in Nyasaland

1916 ◽  
Vol 7 (1) ◽  
pp. 29-50 ◽  
Author(s):  
W. A. Lamborn
Keyword(s):  
Large Scale ◽  
Dry Season ◽  
The South ◽  
Glossina Morsitans ◽  
Lake Shore ◽  
The North ◽  
Sandy Ground ◽  
Artificial Breeding

I remained in the proclaimed area till 6th August 1915, then returning to the vicinity of Monkey Bay for the purpose of endeavouring to establish artificial breeding places on a large scale.While in the proclaimed area I took the opportunity of completing my survey of the distribution of Glossina morsitans, especially in the neighbourhood of Rifu and Kuti described by Dr. Shircore (Bull. Ent. Res., v, p. 87) as “primary centres 1 and 2,” which I had been unable to examine last season before the advent of the rains. As in the case of “ centres 3 and 4,” at Nyansato and Lingadzi respectively, I have not been able to find that the fly is sufficiently localised, even when the dry season is far advanced, as to render feasible any attempt to control it by prophylactic clearing of the bush. In the Rifu district there is a range of rocky hills and high ground running more or less parallel to the lake, with corresponding modification of the soil, so that a zone of scrub has sprung up, from half a mile to two miles in width, consisting very largely of thorn bush, among which are a few big trees. Towards the north this gradually dwindles, to be replaced by the borassus palms usually growing in the sandy ground along the Lake shore, and towards the south it gradually widens out and becomes continuous with the Kuti bush some five miles distant. Throughout its whole extent the fly was plentiful.

scholarly journals OFFSHORE ARTIFICIAL STRUCTURES AND THEIR INFLUENCE ON THE ISRAEL AND SINAI MEDITERRANEAN BEACHES

1982 ◽  
Vol 1 (18) ◽  
pp. 110
Author(s):  
Vaacov Nir
Keyword(s):  
Sandy Beaches ◽  
The South ◽  
The North ◽  
Northerly Direction ◽  
Levantine Basin ◽  
Beach Sediments ◽  
Port Said ◽  
North Beach ◽  
North Sinai ◽  
Quartz Grains

The Israel Mediterranean shore forms a gentle curve from an almost easterly direction in north Sinai to an almost northerly direction in Israel. This shore forms the southeastern corner of the Levantine Basin which itself forms the extreme eastern part of the Mediterranean Sea. The length of the Israel shoreline from Rosh Haniqra near the Lebanese border to northern Sinai in the south is about 230 km, while the Sinai coast from Rafah to Port Said (Fig.1), is almost 200 km long. The coastline region consists largely of Quaternary carbonate cemented quartz sandstone, known by local name "kurkar". Recent faulting is responsible for the shape and, to a certain extent, for the morphology of large parts of the central coastline, which is characterized by kurkar cliffs (Neev et. al_. , 1973 it 1978).Wide sandy beaches are found in the southern parts, while an abraded rocky platforms occur mainly in the central and northern parts, where the beaches are narrow having kurkar cliffs at their backshor.e side. Four different morphological sections can be found in the Israel Mediterranean shore, (Nir, 1982). These differ in their beach and inland morphology on one hand, and in their sedimentological properties on the other. The four different sections from north to south are: 1) Rosh Haniqra to Akko. A sedimentological1y isolated region, bounded on both the south and north. Beach sediments are mostly of local calcareous material of marine origin. Akko promontory is the most northern limit of Nile derived sands and plays as the recent edge of the Nile sedimentary cell (Nir, 1980). 2) Haifa Bay. Wide sandy beaches, bounded on the north by the Akko promontory, and by the Carmel "nose" on the south. 3) Mount Carmel coastal plain, is sedimentologically somewhat isolated region with relatively narrow beaches and small kurkar cliffs. Sediments consist of both local and imported components. 4) The kurkar cliffs and sandy beaches from Caesarea to Rafah. Beaches of differing width having quite uniform petrographic components, mostly quartz grains originating from the Nile river and transported along the Sinai beaches to the Israeli beaches. Some of the present beach components are derivated from the abraded kurkar cliff.

The Madra Çay Delta Archaeological Project, First Preliminary Report

1996 ◽  
Vol 46 ◽  
pp. 167-200 ◽  
Author(s):  
K. Lambrianides ◽  
N. Spencer ◽  
S. Vardar ◽  
H. Gümüş
Keyword(s):  
Coastal Plain ◽  
Preliminary Report ◽  
Sandy Beaches ◽  
The South ◽  
Human Occupation ◽  
The Holocene ◽  
The North ◽  
Sand Spit ◽  
Archaeological Project

In 1995 a new series of multi-disciplinary investigations were initiated by the authors into diachronic human occupation of the coastal plain at Altınova, between Ayvalık and Dikili on the Aegean coast of northwest Turkey (Fig. 1). Altınova lies approximately halfway between the much better-known (and certainly more intensively investigated) archaeological regions of Troy to the north and Bayraklı/Izmir to the south (Fig. 1). Through the plain flows the Madra Çay, and during the Holocene the river's depositional activity has created a large delta clearly visible on most maps as a projection outward into the Lesbos Channel (also known as the Mytilene/Midilli Strait), with the port of Mytilene and the marina of Thermi lying directly opposite (20 km. away) on the island of Lesbos (Fig. 1, Pl. XXII(a)). Altınova's iskele, located in a sand-spit which forms a natural marina, has developed into a modern holiday resort with 5 km. or more of holiday villas along its sandy beaches.

The Temporal and Spatial Evolution of Saltwater Intrusion during Dry Season in the Yangtze River Estuary, China

2014 ◽  
Vol 1010-1012 ◽  
pp. 1099-1103
Author(s):  
Wei Na Zhang ◽  
Yi Gang Wang ◽  
Tong Jun Yang ◽  
Hui Ming Huang
Keyword(s):  
Saltwater Intrusion ◽  
Yangtze River ◽  
River Estuary ◽  
Dry Season ◽  
Yangtze River Estuary ◽  
The Yangtze River ◽  
The South ◽  
The North ◽  
The Yangtze River Estuary ◽  
Temporal And Spatial

Abstract. The saltwater intrusion in the Yangtze River Estuary is very frequent and complicated with a great effect on freshwater supply in Shanghai and nearby cities. By using the hydrologic data observed in dry season, the temporal and spatial variation of the saltwater intrusion in the Yangtze River Estuary were analyzed. The results show that the saltwater intrusion of the south branch is mainly induced by the saltwater spilling over from the north branch, which causes the Chenhang reservoir being plagued by saltwater intrusion during dry season. As the saltwater group from the north branch moving downward along the south branch, the longitudinal salinity distribution present a high-low-high shape during spring tide cycle, low-high-low-high shape during medium tide cycle and low-high shape during neap tide cycle along the south branch-south channel-south passage. Moreover, the north branch is controlled by high saline water with the increase of the salinity in the upstream reach in medium and spring tides, but this phenomenon is vanished in neap tide. In addition, the vertical distribution of salinity is more homogeneous in shoals than that in deep channels, which is induced by mixing degree in water column.

scholarly journals First tomographic observations of gravity waves by the infrared limb imager GLORIA

2017 ◽  
Author(s):  
Isabell Krisch ◽  
Peter Preusse ◽  
Jörn Ungermann ◽  
Andreas Dörnbrack ◽  
Stephen D. Eckermann ◽  
...  
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Wave Packets ◽  
Regional Climate ◽  
Climate Projections ◽  
Atmospheric Models ◽  
The South ◽  
Flight Pattern ◽  
The North ◽  
The Waves

Abstract. Atmospheric gravity waves are a major cause of uncertainty in global atmospheric models. This uncertainty affects regional climate projections and seasonal weather predictions. Improving the representation of gravity waves in global atmospheric models, is therefore of primary interest. In this regard, measurements providing an accurate 3-D characterization of gravity waves are needed. Using the Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA), the first airborne implementation of a novel infrared limb imaging technique, a gravity wave event over Iceland was measured. An air volume disturbed by this gravity wave, was investigated from different angles by encircling the volume with a closed flight pattern. Using a tomographic retrieval approach the measurements of this air mass under different angles allowed for a 3-D reconstruction of the temperature and trace gas structure. The temperature measurements were used to derive gravity wave amplitudes, 3-D wave vectors, and direction-resolved momentum fluxes. These parameters facilitated the backtracing of the waves to their sources on the south coast of Iceland. Two wave packets are distinguished, one stemming from the main mountain ridge in the South of Iceland, a second one from the smaller mountains in the North. The total, area-integrated fluxes of these two wave packets are determined. Following the waves forward with a ray-tracing model highlighted the importance of 3-D propagation, an effect generally neglected in global atmospheric models.

Potential hydro-meteorological impacts over Burundi from climate change

2021 ◽  
Author(s):  
María del Rocío Rivas López ◽  
Stefan Liersch ◽  
Fred Fokko Hattermann
Keyword(s):  
Climate Change ◽  
Rainy Season ◽  
Climate Models ◽  
Climatic Conditions ◽  
Dry Season ◽  
Future Climate ◽  
Internal Displacement ◽  
Climate Projections ◽  
The South ◽  
The North

<p>Burundi is one of the poorest countries in the world with about 65% of the population living below the poverty line and suffering from alarming food insecurity. Its population is highly dependent on rain-fed agriculture, which makes them extremely sensitive to climate variability and extremes for their subsistence. During the last decades, heavy rains, floods, and landslides suffered by Burundi’s population have led to severe famines, death, conflicts, and internal displacement among other fatalities, indicating the high vulnerability of this region to extreme events. Therefore, it is of vital importance to provide detailed information about the potential impacts of climate change in order to enhance adaptation options and preparedness in a country for which little information about climate projections and hydro-climatic impacts is available.</p><p>In this work, we investigated the changes in future climate over Burundi projected by a set of 13 regional climate models, for two future periods, under RCP4.5 and RCP8.5. The projections from CORDEX models have been used as forcing climate for the eco-hydrological Soil and Water Integrated Model (SWIM) in order to assess future changes in mean and extreme river discharge and water availability across Burundi.</p><p>Our results indicate that unabated climate change will lead to faster and more severe warming over Burundi than the global mean. Precipitation will increase in the north of Burundi despite a possible prolongation of the dry season, and will decrease in the south, with the exception of the months core of the rainy season that show the highest rise along the year and across the country. <!-- Option 2. #Two different signals of change were found for future long-term annual mean precipitation in North (+) and South (-) Burundi. Higher increases would take place in the months core of the rainy season in the whole region, while the north may experience a prolongation of the dry season. -->The increase in the frequency, magnitude, and intensity of extreme climate events (daily temperature, dry and wet events) will characterize the future climate in this region according to CORDEX models.</p><p>These changes get translated into increases of discharge in North Burundi across the whole year in all future scenarios and periods (up to 196% in annual streamflow in small catchments and 40% in larger ones), and slight decreases in the south from February to October (up to 7%). The increase of daily and annual extreme river discharges, their probabilities of exceedance, and the decrease in their recurrence intervals implies a higher risk of floods in magnitude and frequency.</p><p>These findings indicate the critical importance of adaptation of land and water management to changing hydro-climatic conditions in Burundi to improve food security and support its development.</p>

scholarly journals Latitudinal Structure of Solitons in the South China Sea

2019 ◽  
Vol 49 (7) ◽  
pp. 1747-1767 ◽  
Author(s):  
Steven R. Ramp ◽  
J.-H. Park ◽  
Yiing Jang Yang ◽  
Frederick L. Bahr ◽  
Chanhyung Jeon
Keyword(s):  
South China Sea ◽  
Internal Waves ◽  
South China ◽  
Near Field ◽  
The South China Sea ◽  
Dimensional Structure ◽  
The South ◽  
China Sea ◽  
The North ◽  
The Waves

AbstractFour current-meter moorings and 12 pressure sensor–equipped inverted echo sounders (PIES) were deployed during summer 2011 in the South China Sea. The goal of the experiment was to obtain synoptic observations of the large-amplitude nonlinear internal waves from the near field to the far field as they propagated west-northwest across the sea. The program was unique because it was the first to observe the latitudinal variability of the wave crests in addition to the transformations along a single east–west transect. The waves were strongest down the center of the PIES array along roughly 20°45′N and were weaker off axis in both directions. Both a-waves and b-waves arrived earlier in the south than the north, but with different lag times indicating different propagation directions and therefore different sources. The waves were classified by their arrival patterns and source locations and not by their amplitude or packet structure. The Stanford Unstructured Nonhydrostatic Terrain-Following Adaptive Navier–Stokes Simulator (SUNTANS) model, calibrated against the array, showed that the a-waves developed out of the internal tide spawned in the southern portion of the Luzon Strait and the b-waves originated in the north. The northern tides were refracted and suffered large dissipative losses over the shallow portion of the western ridge, whereas the southern tides propagated west-northwest unimpeded, which resulted in a-waves that were larger and appeared sooner than the b-waves. The results were consistent with previous observations that can now be understood in light of the full three-dimensional structure of the internal waves and tides in the northeastern South China Sea.

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

US and Russian policies and strategies in the Middle East: Iraq and Syria as a model

2019 ◽  
pp. 220
Author(s):  
Esraa Aladdin Noori ◽  
Nasser Zain AlAbidine Ahmed
Keyword(s):  
Middle East ◽  
East Asia ◽  
Balance Of Power ◽  
Western World ◽  
International Conflicts ◽  
The South ◽  
The West ◽  
The North ◽  
East Region ◽  
Middle East Region

The Russian-American relations have undergone many stages of conflict and competition over cooperation that have left their mark on the international balance of power in the Middle East. The Iraqi and Syrian crises are a detailed development in the Middle East region. The Middle East region has allowed some regional and international conflicts to intensify, with the expansion of the geopolitical circle, which, if applied strategically to the Middle East region, covers the area between Afghanistan and East Asia, From the north to the Maghreb to the west and to the Sudan and the Greater Sahara to the south, its strategic importance will seem clear. It is the main lifeline of the Western world.

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