Friday, March 27, 2015

Do they still call it Antarctica if its warm?
Antarctica, Earth's coldest, most barren continent, may have just set a remarkably unusual weather record. An Argentinian research station on the rapidly warming Antarctic Peninsula recorded a high temperature of 63.5 degrees Fahrenheit (17.5 degrees Celsius) on March 24, according to reports from Weather Underground. 
If this is investigated and verified by the World Meteorological Organization (WMO), it could become the highest temperature on record for the entire continent of Antarctica.
The warmth at the Esperanza research station came one day after a nearly identical high temperature was logged at another Argentinean base, known as Base Marambio, also located along the Antarctic Peninsula. Interestingly, the mild conditions occurred during the Antarctic fall, not the height of summer.
More broadly, the Antarctic ice sheet is proving to be far more dynamic than scientists thought was the case just two decades ago. A study published on Thursday, for example, found that the loss rate of Antarctic ice shelves, which play a crucial roll in buttressing inland glaciers and preventing them from sliding quickly into the sea, has accelerated by 70% in just the past decade. 
This may mean that climate scientists will need to raise their global sea level rise projections. Such projections also take into account ice loss from the Greenland ice sheet, where temperatures are also increasing rapidly.

Southern California Turns White?

Beaches and streets in Southern California suddenly turned white during a hailstorm late Monday morning, stunning residents who quickly ran outside to get a picture or play in the unusual weather.
    The hail was reported in areas like Huntington Beach and Long Beach – areas that have seen little precipitation of any kind in recent months due to a long-term drought that has gripped the West.
    "Upper-level energy associated with Winter Storm Thor has been triggering thunderstorms along the California coast since this past weekend," said meteorologist Chris Dolce. "These thunderstorms produced small hail that whitened the ground in parts of the Bay Area on Saturday and did the same in Southern California on Monday."
    Winter Storm Thor is expected to move from the West Coast through the Plains and East, affecting parts of 48 states on the way.
    Check out more of the most awesome images from the Southern California hailstorm below.

    Unusual Weather Accelerates Summer Crop Season

    Californian growers are gearing up for another early season of their summer crops following record high temperatures in parts of the state. apricot_69882310 thirdsq
    California Fresh Fruit Association (CFFA) president Barry Bedwell said the industry may be roughly two to three days ahead of last season, which was early in itself.
    The high temperatures began around Friday (March 13) last week, when a high pressure system built up over parts of the state.
    “I think that once again we’re experiencing an early season, and this heat certainly confirms and accelerates that,” he told
    “Having said that, this weather is highly unusual and once again continues to set records. That 91°F (33°C) I think we had in this area [Fresno] on Sunday was an all-time record for the date by four degrees, and one of the hottest temperatures we have seen in the month of March ever.”

    Weather Causes Unusual Amount of Arctic Ice

    Satellites that take pictures of ice in the Arctic are showing the lowest amount of sea ice ever recorded, according to scientists at the National Snow and Ice Data Center in Colorado.

    “The middle part of the country and the east coast were getting a lot of the cold winter weather, whereas here in Alaska, we were getting more of the warmer weather,” Schreck explained. “There was warm air coming into the state that we don’t usually see.”
    But Schreck said the ice closest to Alaska in the Bering Sea did not look significantly different from last year, with the exception that it may be thinner. She said it’s not unusual for the ice pack to change on an almost daily basis.
    “What happens with the ice — especially during the spring — is so reliant on weather patterns,” Shreck said. “The current weather patterns, not what has happened over the last few months. So it is normal for it to retreat and grow back and retreat and grow back throughout the spring time.”

    Shreck says it’s possible the ice pack in the Bering Sea is still growing, and may not reach it’s maximum extent for another week or so.

    Big storms increase tropical rainfall

    Joint research from the Monash branch of the Australian Research Council Centre of Excellence for Climate System Science (ARCCSS) and NASA published in Nature found even though other types of rainfall has decreased in frequency and the total number of thunderstorms remained the same, the increase in big storms had elevated total rainfall.
    Thunderstorms play an important role in rainfall in the tropics. Despite organised deep convective storms only occurring 5% of the time in the world's equatorial regions, they deliver almost 50% of all its rainfall.
    The research has also contributed to answering the important question whether the increase in rainfall observed in the tropics was simply caused by the fact of a warmer atmosphere or whether the underlying circulation in that region had changed.
    The changes to the deep convection discovered in the study suggested a dynamic change in the climate system was responsible for the change in rainfall.
    The revelation that large thunderstorms appear to be the source of increased precipitation in the tropics explains why climate models may have difficulties in accurately representing the details of tropical rainfall.
    The small-scale processes giving rise to thunderstorms make their direct simulation in climate models impossible given current computing power.
    "This limitation, which is a well-known issue in global climate models, might well be a contributing factor to the precipitation errors and the bias towards light rain," said another author from Monash University, Prof Christian Jakob.
    "Given how important these large storms are to rainfall in the tropics, it is vital that there is a renewed effort to represent convective organisation in global climate models if we are to fully understand precipitation changes in the future."

    Climate Change does not cause extreme weathers

    Repeated cold snaps led to temperatures far below freezing across the eastern United States in the past two winters. Parts of the Niagara Falls froze, and ice floes formed on Lake Michigan. Such low temperatures had become rare in recent years. Pictures of icy, snow-covered cities made their way around the world, raising the question of whether climate change could be responsible for these extreme events.
    It has been argued that the amplified warming of the Arctic relative to lower latitudes in recent decades has weakened the polar jet stream, a strong wind current several kilometres high in the atmosphere driven by temperature differences between the warm tropics and cold polar regions. One hypothesis is that a weaker jet stream may become more wavy, leading to greater fluctuations in temperature in mid-latitudes. Through a wavier jet stream, it has been suggested, amplified Arctic warming may have contributed to the cold snaps that hit the eastern United States.
    Scientists at ETH Zurich and at the California Institute of Technology, led by Tapio Schneider, professor of climate dynamics at ETH Zurich, have come to a different conclusion. They used climate simulations and theoretical arguments to show that in most places, the range of temperature fluctuations will decrease as the climate warms. So not only will cold snaps become rarer simply because the climate is warming. Additionally, their frequency will be reduced because fluctuations about the warming mean temperature also become smaller, the scientists wrote in the latest issue of the Journal of Climate.
    Using a highly simplified climate model, they examined various climate scenarios to verify their theory. It showed that the temperature variability in mid-latitudes indeed decreases as the temperature difference between the poles and the equator diminishes. Climate model simulations by the Intergovernmental Panel on Climate Change (IPCC) showed similar results: as the climate warms, temperature differences in mid-latitudes decrease, and so does temperature variability, especially in winter.
    Temperature extremes will therefore become rarer as this variability is reduced. But this does not mean there will be no temperature extremes in the future. "Despite lower temperature variance, there will be more extreme warm periods in the future because the Earth is warming," says Schneider. The researchers limited their work to temperature trends. Other extreme events, such as storms with heavy rain or snowfall, can still become more common as the climate warms, as other studies have shown.

    Tuesday, March 24, 2015

    California Statewide Snowpack Now Below Record Low Benchmark

    Snowpack in California has reached a new low milestone that has not been seen in more than 30 years. It's just the latest chapter in the dire drought now entering its fourth year.
    According to the California Nevada River Forecast Center, snowpack statewide was just nine percent of average as of March 23. That figure breaks the previous snowpack record for this point in the snow season, set back during the 1976 to 1977 season. 
    "That's not a typo, it's now in single digits," the River Forecast Center said in a Facebook post announcing the new low. 
    Winter storms capable of delivering feet of snow have been scarce so far in 2015. The animation below shows how the snowpack has receded greatly from early January into the middle of March.
    The overall statewide snowpack is calculated based on the combined snow water content of the northern, central and southern Sierra Nevada.
    On March 23,  the central and southern Sierra Nevada were both at 10 percent of average, while the northern Sierra Nevada was at seven percent of average.
    This snow water content is very important for the water supply in California. As the snow melts later in the spring, it helps to replenish reservoirs in the state. As of March 23, all reservoirs near the Sierra Nevada and in northern California were at 60 percent or less capacity, according to the California Department of Water Resources.
    Although northern California reservoirs got a boost from heavy rainfall in February, snow was confined to the highest elevations. This means the moisture-laden storm systems did very little to help the mountain snowpack.