A beautiful and deadly natural phenomenon, lightning is simply a sudden, electrostatic discharge - a ‘spark’ or ‘flash’ as charged regions in the atmosphere temporarily equalise themselves through this discharge. It is the polarity of lightning discharge that can affect the way it spreads and branches in space and time.
We may be at the end of the heatwave season, but Urban Heat Islands (UHI) can occur at any time of the year. Here, we explore the UHI and its implications through some bite-sized Q&As.
Q. What is the Urban Heat Island (UHI) effect?
In simple terms, fog is cloud at ground level. It can cover vast areas, vary in density and thickness, and, like clouds, comprises of a various types.
Photo: The picture is actually an animation, showing global temperature change since 1850.Source: Ed Hawkins, ClimateLabBook
Climate scientist, Ed Hawkins from the University of Reading has produced a revolutionary way to illustrate global warming over the past 160 years. Ed's graphic's has been retweeted more than 15,000 times, and now Jay Alder, from the USGS has stretched the the spiral out to model data out to 2100.
The air around us is made up of nitrogen (78%), oxygen (20.9%), carbon dioxide (0.03%), argon (0.9%) and other gases (0.17%). These other gases are made up of substances that can cause health problems, including:
Although not always a ‘welcome friend,’ precipitation is essential to the life on Earth and the latent heat released from its formation provides much of the energy that drives atmospheric circulation.
Precipitation takes a variety of forms and each develop in different ways:
The name El Niño, Spanish for ‘child’or ‘the Christ child’, was first used by fishermen along the coasts of Ecuador and Peru to refer to a warm ocean current that typically appears around Christmastime and lasts for several months. Fish are less abundant during these warm intervals, so fishermen often took a break to repair their equipment and spend time with their families.
by Dr. Peter N. Francis. Manager at Satellite Imagery Applications Group, Met Office, UK.
Observations of the weather are made 24 hours a day, all over the world. The main observations are from weather satellites, balloons, landbased instruments, ships, buoys and aircraft.
Generalised model of thermohaline circulation, adapted from NASA.
The Atlantic Meridional Overturning Circulation (AMOC) is a system of currents in the Atlantic Ocean, including the Gulf Stream that circulates a vast amount of heat from the tropics towards the North Pole disseminating the cold, saline, dense waters towards the Tropics and even further south towards the South Pole. The figure above captures that in a generalised worldwide model of thermohaline (thermo- referring to temperature and –haline referring to salt content) circulation.
The Aurora Borealis, also known as the Northern Lights, and Aurora Australis (Southern Lights) in the Southern Hemisphere, are a spectacular natural phenomenon. They light up a night sky, dancing around in fantastic colours. There are few places in the Northern Hemisphere where you can see them, but they can be elusive if you are really unlucky. Here we explain the science behind the Northern Lights and share few tips on how to maximise your chances of witnessing this wonderful spectacle.
