Archive for the ‘Climatology’ Category
Recent research supports the hypothesis that during the Cretaceous (from 145 million years ago to 65 million) fires were much more common than was thought until now.
At that time the world was subjected to an intense greenhouse effect and global temperatures were higher than today. The lightning would have been the main trigger of these fires, but this period had high concentrations of atmospheric oxygen. More heat and more oxygen mean that the vegetation now, even now rarely burn, was burnt down with ease.
The team of Ian Glasspool of the Field Museum of Natural History in Chicago, USA, and Andrew C. Scott and Sarah Brown of the Royal Holloway (University of London) traced the fire activity in the fossil record using for this the presence of charcoal deposits, creating a global database for this time interval. Charcoal is the remnant of vegetation burned and stored easily in the fossil record. Read the rest of this entry »
A new study shows how much soot reduces the reflectance of snow and ice, an effect that contributes to global climate change. Soot is a pollutant emitted in significant quantities by many power plants, diesel engines, and not a few devices for cooking or heating. Soot can travel great distances and deposited in remote areas far from emission sources.
Snow is the natural surface on earth that reflects more light. When it snows, snowflakes sweep the soot being present in the local air and is taken to the ground, so that the surface of the layer of snow resulting contains soot particles.
That was just depositing soot on snow and ice layers, such as those covering large areas of polar regions, or those which are common at high altitudes in the mountains, icy white layer darkens, which brings an inevitable reduction reflectance of snow. Read the rest of this entry »
The snow is as much a risk as a source of fresh water in various parts of the world. Many important decisions relating to transport, water management, and other areas of activity should be taken from precise measurements of how varying the thickness of snow covers over large areas.
Those responsible for emergency services are based on measurements of the snow on the ground to mobilize the snowplows or to decide whether to close roads and airports during storms more severe. In mountainous areas, emergency personnel need accurate information on the depth of snow cover to assess the potential threat of landslides or flooding, and also know the amount of water available during the spring thaw or summer of the masses alpine water ice. Read the rest of this entry »
Climate models fail to accurately represent the desirable individual clouds and the processes occurring in them because they lack the spatial resolution that would allow them to simulate properly.
Now, however, scientists have developed a new tool that will allow the clouds observed in the sky are better represented in climate models.
Traditionally, satellite observations of this kind allow us to infer the properties of clouds by light reflecting back into space, or the thermal emission of the planet. However, to use with the necessary precision satellite data in climate model evaluation, we need a tool that allows a more accurate comparison between the simulated virtual cloud and climate model cloud properties from satellite measurements. Read the rest of this entry »
Provide insightful information on the role of insoluble particles of dust in the formation of raindrops in the clouds could significantly improve the accuracy of regional climate models, especially in areas of the world that have significant amounts of mineral aerosols the atmosphere. A better understanding of this role could also be useful for global climate models.
The properties of clouds can have a significant influence on climate. Therefore it is very important to know in depth the climatic effects of aerosols such as dust, which is far from achieved, and in fact is one of the largest uncertainties in climate change models.
Scientists have long recognized the importance of soluble particles such as salt and sulphates, in the creation of droplets that form clouds and lead to precipitation. But so far, the role of insoluble particles, mostly windswept dust from places such as deserts, has had little presence in the climate models. Read the rest of this entry »
Some aspects of the link between decadal solar variability and winter weather in United Kingdom, Northern Europe and some regions of North America have been clarified.
The study, conducted from the British National Weather Service, and the specialists who worked at Imperial College London and University of Oxford, shows that the reduction of ultraviolet light from the sun can contribute to colder winters in many regions of the northern hemisphere. The harsh British winters in 2009-10 and 2010-11 are an example of this.
The years with increased ultraviolet radiation have the opposite effect. In previous studies we noted the connection between solar variability and winter weather, but new research by the team of Adam Scaife, Sarah Ineson and Joanna Haigh says this is not mere coincidence. Read the rest of this entry »
During the ice ages, not just the global climate was cooler but there was less atmospheric carbon dioxide. Since humans did not cause this change in the concentrations of carbon dioxide (CO2), this implies that the carbon was absorbed by another tank.
An obvious place to look for the missing carbon is the sea, where it is stored more than 90 percent of the carbon potential mobility.
The Pacific Ocean is the largest in terms of volume. The deep water mass that has been longer isolated from the atmosphere and the richest in carbon is found today in the Northeast Pacific, so the researchers directed their efforts towards it. Read the rest of this entry »
Until now, many scientists believed that the sightings of triple rainbow were as fanciful as the myth of the end of the rainbow is a treasure hidden by an elf. These optical legendary rarities have been finally confirmed through the perseverance of photographers and a new weather model that provides the scientific basis can be found.
Raymond Lee, a professor of meteorology at the U.S. Naval Academy, it was who took those pictures, but made them possible. A year ago, Lee predicted triple rainbow what circumstances might appear, and encouraged hunters to find rainbows.
Although surprisingly rare, triple rainbow is a natural product of the combination of refraction, dispersion, and reflection within the drops of rain. These are the same processes that create all rainbows, but carried to an extreme situation, which can produce these variants as impressive. Read the rest of this entry »
In Australia, as in other nations, scientists are taking steps to improve long-term estimates of changes in wind speed. These estimates are vital to the rapid growth that is recorded in the use of wind energy, that serve to reduce the risk of build windmills on sites that are later found to be inadequate.
Some studies have predicted a decrease in wind speed in various parts of the world, including Australia. However, more recent research by the CSIRO results that in fact, for practical purposes for wind energy, the average speed of the wind in Australia is increasing.
A team of scientists from CSIRO marine and atmospheric research has completed a thorough analysis of observations about the speed of the wind, in order to be able to predict the long-term trends in the speed of the wind in Australia. Read the rest of this entry »
The global emissions of carbon dioxide (CO2), which are the main cause of the global warming-up, it enlarged in 45 percent between 1990 and 2010, reaching 33,000 million tons, the highest quantity since the start of the Industrial Revolution.
This increase occurred despite reductions in emissions in several industrialized nations during the same period. The new report on long-term trend in global CO2 emissions, presented by the Joint Research Centre of the European Commission and the Netherlands Environmental Assessment Agency (PBL) shows large differences between the industrialized countries. Read the rest of this entry »