Saturday, 3. May 2008, 08:48:53
hurricanes, natural hazards
At the time of writing the Severe Cyclonic Storm NARGIS is passing over Yangon (Rangoon). It stayed more or less on the course I mentioned a few days ago (See this
post). Late Friday night it hit the Myanmar coast with wind-speeds around 210 km/h. Up to 7.45 million people may be affected by wind speeds of hurricane strength or above. In addition, 1.78 million people are living in coastal areas below 5 m and may therefore be affected by storm surge.
The storm made landfall around the mouth of the Ayeyawaddy (Irrawaddy) river, about 220 kilometres Southwest of Yangon, before hitting the country's economic hub. Meteorologists have warned of a tidal surge up to 3.5 metres due to the cyclone.
It is still too early to get an overview over damage and casualties. Myanmar has been ruled by the military since 1962 and the junta restricts media activities, so information could be slow in coming out. It is not known whether damage from the storm would affect a referendum next Saturday on a new constitution which the ruling junta says will pave the way for democratic elections in 2010. No doubt the damage will be extensive as the cyclone passed through many densely populated areas. It obviously wreaked havoc in Yangon (where the airport was closed and electricity fell out) and the Irrawaddy delta town of Bassein.
Cyclone Nargis missed neighbouring Bangladesh, where fishing crews were told to stay close to shore and not to venture into the Bay of Bengal, after fears the storm would slam into the Southeast coast.
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http://ap.google.com/article/ALeqM5greyFH3qkj9mc9oagSoulgjN4KHgD90E15LO0 •
http://www.reliefweb.int/rw/RWB.NSF/db900SID/MUMA-7EAAR3?OpenDocument •
http://afp.google.com/article/ALeqM5h5kIScmy1U7oTnHZjavFOqWLKmtA •
http://www.hindu.com/thehindu/holnus/003200805031021.htm •
http://www.terradaily.com/reports/Cyclone_to_hit_Bangladesh_and_Myanmar_coast_official_999.html •
http://earthobservatory.nasa.gov/NaturalHazards/shownh.php3?img_id=14809Ole
Tuesday, 29. April 2008, 19:03:58
climate, natural hazards, hurricanes
The tropical cyclone Nargis in the Bay of Bengal is on course towards the west coast of Myanmar. It is expected to hit the lowest central part of the country, the Ayeyarwady (or Irrawaddy) delta near the great city of Yangon (also known as Rangoon) and the low coast to the north of it. In the northern hemisphere a cyclone rotates counter-clockwise, because of the coriolis force, which means that water masses from the Bay of Bengal will be forced far over land on the right side of the cyclone, where the delta is. Further north the mountain range Arakan Yoma (also known as the Chin Hills) forms a wall towards the bay, and here Nargis is expected to release torrential rains, when the humid air is forced up over the up to 3000 m high mountain tops.
The majority of
Burma's Myanmar's population lives in the Ayeyarwady valley. The upper and central portions of the Ayeyarwady delta are almost entirely under cultivation, principally for rice. The climate is monsoonal climate, with an average annual rainfall of about 1,500-2,000 mm in the north increasing to 2,500 mm in the southeast and 3,500 mm in the southwest. Over 90% of the rain falls between mid May and mid November.
Sorry at my age we sometimes have difficulties with "new" geographical names, but I do my utmost to keep to the official, politically correct, spelling.
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http://www.gdacs.org/reports.asp?eventType=TC&ID=NARGIS-08&system=asgard&alertlevel=Green&glide_no=&location=&country=&new=true •
http://www.arcbc.org.ph/wetlands/myanmar/mmr_irrdel.htm
PS of 30 April 2008Bangladesh raises storm alert and urges swift rice harvest:
http://www.alertnet.org/thenews/newsdesk/DHA224084.htmThe cyclone can also be tracked here, with up to 72 hours lead:
http://tsr.mssl.ucl.ac.uk/PS of 3 May 2008: See follow up
here.
Friday, 1. February 2008, 09:40:14
hurricanes, natural hazards
Many researchers believe warming is causing Atlantic hurricanes to get stronger, while others aren't so sure. As late as last week U.S. researchers challenged the view that as hurricanes feed on warm water global warming would lead to more powerful storms - saying global warming could reduce the number of hurricanes hitting the United States with warmer waters resulting in atmospheric instabilities that prevent storms from forming.
According to an article published yesterday, 31 January 2008, in Nature sea surface warming contributes largely to the recent increase in Atlantic hurricane activity. I am referring to
Large contribution of sea surface warming to recent increase in Atlantic hurricane activity by Saunders & Lea.
The researchers claim that 0.5°C increase in sea surface temperature is associated with a 40 percent increase in hurricane frequency and activity. They showed that ocean warming is directly linked to the frequency, strength and duration of hurricanes. The authors looked at storms that formed in the tropical North Atlantic, Caribbean Sea and Gulf of Mexico - a region that produced nearly 90 percent of the hurricanes that struck the United States between 1950 and 2005. The results refer to increase in hurricane activity relative to the fifty year (1950-2000) average between 1996 and 2005.
In the period 1950-2000 there were around six hurricanes per year on average, roughly half of which were intense hurricanes. But for the 10 years from 1996 to 2005, the tally rose to about eight hurricanes per year, about four of which were intense ones. After stripping out the role of wind in hurricane generation, the researchers calculate that an increase of 0.5 degrees Celsius was responsible for about 40 percent of the rise in hurricane activity.
The paper could be a major contribution to scientists struggling to understand impacts from global warming.
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http://www.nature.com/nature/journal/v451/n7178/abs/nature06422.html •
http://www.scientificblogging.com/news_releases/study_links_north_atlantic_sea_surface_temperature_and_hurricane_activity_0 •
http://www.terradaily.com/reports/Warmer_seas_boosted_hurricane_frequency_by_40_percent_study_999.html •
http://www.eurekalert.org/pub_releases/2008-01/ucl-iha012808.php •
http://www.guardian.co.uk/feedarticle?id=7268579 •
http://www.sciencedaily.com/releases/2008/01/080130130647.htm •
http://physicsworld.com/cws/article/news/32646;jsessionid=301BEAC2887974FB134045748FF44F28
Saturday, 1. December 2007, 10:50:48
hurricanes, oceanography, climate change
After the
record-breaking hurricane season in 2005 it was suspected that global warming is leading to stronger and more frequent tropical storms (hurricanes, typhoons, and cyclones). Satellites have only given us sufficient data over the last twenty years or so, but nevertheless recently documented trends in the existing records of hurricane intensity and their relationship to increasing sea surface temperatures suggest that hurricane intensity may be increasing due to global warming. It seems however that the Atlantic is more vulnerable to climate change than the Pacific and the Indian Ocean.
According to a paper published on 29 November 2007 in the
Bulletin of the American Meteorological Society warmer ocean water is only part of the story. Wind and precipitation over the ocean also play their role. The atmosphere and the ocean interact with each other in a distinct way creating a special basin wide north south circulation pattern, called
Meridional Mode (meaning along longitudinal meridians and thus north/south and south/north directed).
In a study published in
February 2007, Kossin and his co-authors created a record of hurricane data that accounted for the significant improvement in storm detection that followed the advent of weather satellites. An analysis of this recalibrated data showed that hurricanes have become stronger and more frequent in the Atlantic Ocean over the last two decades. The increasing trend, however, is harder to identify in the world's other oceans. The other oceanic basins have their own modes of ocean-atmosphere variability.
Because higher sea surface temperatures in the Atlantic act in concert with the
Atlantic Meridional Mode, Vimont and Kossin suggest that Atlantic hurricanes will be more sensitive to climate changes than storms in other ocean basins.
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http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2FBAMS-88-11-1767 •
http://www.news.wisc.edu/14493 •
http://www.physorg.com/news115574276.html •
http://www.sciencedaily.com/releases/2007/11/071129183753.htm •
http://www.terradaily.com/reports/Recipe_For_A_Storm_The_Ingredients_For_More_Powerful_Atlantic_Hurricanes_999.html •
http://www.agu.org/pubs/crossref/2007/2007GL029683.shtml •
http://www.aos.wisc.edu/~dvimont/Research/Meridional: In meteorology, a flow, average, or functional variation taken in a direction that is parallel to a line of longitude; along a meridian; northerly or southerly; as opposed to zonal.
Meridian: An imaginary great circle on the earth's surface passing through the North and South geographic poles. All points on the same meridian have the same longitude.
climate change, oceanography, hurricanes
