Wednesday, May 22, 2013
GPS data could improve tsunami early warnings
offer detailed information about the events within minutes of an earthquake occurring. They believe the technology could have improved alerts issued when the devastating tsunami hit Japan in 2011. The study is published in Natural Hazards and Earth Systems Sciences . When an underwater earthquake happens, with the power to generate a tsunami, every second counts. The shifting tectonic platescan generate giant walls ofwater that can travel towards land in minutes, giving little time to put evacuation plans into action. Precise measurements Existing early warning systems use seismological data, measuring the wavesof energy that are generated as the earth moves and shakes. You can predict thetsunami and see how high a wave could be expected, with some accuracy Dr Andreas Hoechner, GFZ German Research Centre for Geosciences But in the vital first stagesof an earthquake, this is not always reliable. Now a team from the GFZ German Research Centre for Geosciences says that satellite navigation technology could help. GPS sensors placed around the coastlines of vulnerable countries could make highly precise measurements of how underwater tremors shift the ground. Lead researcher Dr Andreas Hoechner explained: "In case of a subduction earthquake, one plate slips under another plate. "It is measured in terms of relative displacement. Thisdeformation is mostly above the source, but the coastal area is also deformed and this can be picked up by GPS." He said that this information could be used to reconstruct the source of the earthquake and calculate its magnitude. "Then you can then predictthe tsunami and see how high a wave could be expected, with some accuracy." This process would take a matter of minutes, which would allow alerts to be issued extremely quickly. Disseminate warnings In the case of the 2011 tsunami that killed 16,000 people in Japan, the technology could have made a significant difference. Although the Japan Meteorological Agency issued a warning three minutes after the earthquake hit, it underestimated the scale of the event. It suggested that the quake was 7.9 magnitude; it was actually 30 times more powerful. By looking at data collectedby GPS stations in Japan - which at the time were not used to measure earthquakes - the researchers calculated that this would have provided an accurate estimate of the magnitude within three minutes. A number of countries are now installing GPS networks, including Chile and the US. But Dr Hoechner said that as well as having accuratealert systems, well thought-out evacuation plans were also essential. He said: "One point is to have the technology to realise what the earthquake is and where tsunami will be. But it is at least as important is to disseminate the warning. "You have to have the infrastructure to transmit this information to the population, and the population has to be readyto know what to do."
Oklahoma tornado: Mayor of Moore pushes for shelter law
Monday, May 20, 2013
TROPICAL MONSOON NATURAL VEGETATION
THE TROPICAL MARINE CLIMATE
THE RETREATING MONSOON
Wednesday, April 24, 2013
THE SEASONS OF THE TROPICAL MONSOON CLIMATE
CLIMATIC CONDITIONS IN TROPICAL MONSOON LANDS
Tuesday, April 23, 2013
THE TROPICAL MONSOON AND TROPICAL MARINE LANDS
The tropical monsoon lands are with on-shore wet monsoons in the summer and off-shore dry monsoons in the winter. They are best developed in the sub-continent of India, Pakistan and Bangladesh, Burma, Thailand, Laos, the Khmer Republic, parts of Vietnam and South China and Northern Australia. Outside this zone, the climate is modified by the influence of the on-shore Trade Winds all the year round, and has a more evenly distributed rainfall. Such a climate, better termed the Tropical Marine Climate, is experienced in Central America, West Indies, North-eastern Australia, the Philippines, parts of East Africa, Madagascar, the Guinea Coast and Eastern Brazil.
Sunday, January 29, 2012
THE EQUATORIAL REGION
DISTRIBUTION
The equatorial, hot, wet climate is found between 5 o north and 10 o south of the equator. Its greatest extent is found in the lowlands of the Amazon, the
Saturday, July 18, 2009
DISTRIBUTION
The equatorial, hot, wet climate is found between 5 o north and 10 o south of the equator. Its greatest extent is found in the lowlands of the Amazon, the
CLIMATE
Temperature: the most significant feature of the equatorial climate is its great uniformity of temperature round the year. The mean monthly temperatures are around 27oC (80 oF) with very little variation. There is no winter, cloudiness and heavy rainfall help to moderate the daily temperature, so that even the equator itself cannot be unbearable. Also regular land and sea breezes help in keeping a truly equable climate. The temperature range within the equatorial region are around 2° C (4° F) or less for example Warri (Nigeria) has its hottest Month around 28° C (82° F) and its collest month around 26° C (78° F), therefore having its annual range around 2° C (4° F)
Precipitation: precipitation in the equatorial region is heavy, between 60 inches and 106 inches and is well distributed throughout the year. There is no month without rain and there are two periods of maximum rainfall, July and September, which occur shortly after the equinoxes. Least rain falls at the January and December solstices. But this simple pattern may be altered or changed by local conditions.
Below is a chart showing the annual precipitation of Ukpo town (
Due to the great heat in the equatorial belt, mornings are bright and sunny and there is much evaporation and conventional air currents are set up, followed by heavy downpours of Convectional rain in the afternoons from the towering Cumulonbus cloud. Thunders and lightening often accompany the torrential showers. The amount of rainfall recorded in one afternoon may be as much as the deserts receive for the entire year.
NATURAL VEGETATION
Equatorial regions support a luxuriant type of dense vegetation (the tropical rain forest) because of the very heavy rainfall (over 80 inches) and uniformly high temperature (27 ºC / 80 ºF). In the Amazon lowlands, the forest is so dense and so complete in its vegetation extravagance. The growing season in equatorial region is not restricted by either drought or cold, planting is down throughout the year.