Arctic sea ice has thinned dramatically

Arctic sea ice thinned dramatically between the winters of 2004 and 2008—NASA

Analysis of data from a NASA Earth-orbiting spacecraft shows that “Arctic sea ice thinned dramatically between the winters of 2004 and 2008, with thin seasonal ice replacing thick older ice as the dominant type for the first time on record.”  The latest discovery “provide further evidence for the rapid, ongoing transformation of the Arctic’s ice cover.”

ICESat measures the distances to the top of the snow cover and to the sea surface. The difference between the two quantities gives the total “freeboard” measurement; that is, the amount of ice above the water line relative to the local sea level. Credit: Courtesy of Norbert Untersteiner, University of Washington

NASA says their and the University of Washington in Seattle researchers carried out “the most comprehensive survey to date using observations from NASA’s Ice, Cloud and land Elevation Satellite, known as ICESat,” to determine “the first basin-wide estimate of the thickness and volume of the Arctic Ocean’s ice cover.”  Their research team, led by Ron Kwok of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., published its findings on July 7 in the Journal of Geophysical Research-Oceans.

This schematic shows the geometric relationship between freeboard (the amount of ice above the water line), snow depth, and ice thickness. Buoyancy causes a fraction (about 10 percent) of sea ice to stick out above the sea surface. By knowing the density of the ice and applying “Archimedes’ Principle” — an object immersed in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object — the total thickness of the ice can be calculated. Credit: Ron Kwok, NASA/JPL

ICESat measurements of winter multi-year ice cover in the Arctic Ocean between 2004 and 2008, along with the corresponding downward trend in overall winter sea ice volume, and switch in dominant ice type from multi-year ice to first-year ice. Credit: Ron Kwok, NASA/JPL

ICESat measurements of winter multi-year ice cover in the Arctic Ocean between 2004 and 2008, along with the corresponding downward trend in overall winter sea ice volume, and switch in dominant ice type from multi-year ice to first-year ice. Credit: Ron Kwok, NASA/JPL

Data visualization of Arctic sea ice thickness, as measured by ICESat, shows the decline of the thickest ice (white, 4 to 5 meters thick) and increase in thinner ice (deep blue, 0 to 1 meter) from 2003 to 2008. Credit: NASA Goddard’s Scientific Visualization Studio.

Data visualization of ice thickness, as measured by ICESat, shows the yearly growth (winter) and retreat (fall) of ice in the Arctic Ocean. Credit: NASA Goddard’s Scientific Visualization Studio

More Images Available at Source

Related Links:

• Arctic Sea Ice Reaches Lowest Coverage For 2008
• Satellites Show Arctic Literally on Thin Ice

FEWW Links

• Strong Quake Strikes Baffin Bay

China, Vietnam Submereged Under Floods

Earth Observatory Image [acquired June 29, 2009 – July 5, 2009]

Intense Rain Floods China and Vietnam

Floods swept across southern China and northern Vietnam in the wake of several days of extreme rain in early July 2009. This image, based on data collected by the Tropical Rainfall Measuring Mission (TRMM) satellite, shows rainfall anomalies for the week of June 29 through July 5, 2009. Blue indicates regions where rainfall was much heavier than average, while brown indicates that less rain fell than average. A broad swath of blue covers southern China and northern Vietnam, revealing patterns of heavy rain during the week. NASA image courtesy Jesse Allen based on data provided by the TRMM team. Caption by Holli Riebeek.

Widespread flooding and landslides have killed 75 people, with up to 1.5 million people left homeless in southern China, according to various reports. In Vietnam, up to 50 people may have died from severe weather, and dozens are missing. More intense rain was forecast in the region.

Related Links:

• Drought and Deluge
• Floods, Extreme Rain Events, Rising Sea Levels, Storms

Strong Quake Strikes Baffin Bay

Magnitude 6.1 Earthquake Occurred at Baffin Bay off the NW Coast of Greenland

FEWW Moderators believe magnitude of the seismicity most likely intensified as a result of icemelt in the region.

Other examples of climate-intensified natural events would be posted on this blog when they occur.

Location of earthquake is marked on the Bathymetric map of the Arctic Ocean. Original Map: NOAA

Details of the Earthquake

• Magnitude: 6.1
• Date-Time:
  • Tuesday, July 07, 2009 at 19:11:45 UTC
  • Tuesday, July 07, 2009 at 02:11:45 PM at epicenter

• Location: 75.325°N, 72.312°W
• Depth: 10 km (6.2 miles) set by location program
• Region: BAFFIN BAY
• Distances:
  • 170 km (105 miles) SW of Qaanaaq (Thule), Greenland
  • 315 km (195 miles) ESE of Grise Fiord, Nunavut, Canada
  • 1455 km (910 miles) NNW of NUUK (GODTHAB), Greenland
  • 3330 km (2070 miles) N of Montreal, Quebec, Canada

• Location Uncertainty: horizontal +/- 3.8 km (2.4 miles); depth fixed by location program
• Parameters:  NST=216, Nph=216, Dmin=>999 km, Rmss=0.98 sec, Gp= 58°, M-type=centroid moment magnitude (Mw), Version=T
• Source: USGS NEIC (WDCS-D)
• Event ID us2009iubh

Earthquake Location:

10-degree Map Centered at 75°N,80°W

Seismic Hazard Map

Historic Seismicity

Related Links:

• Volcanoes [FEWW Links]
• Earthquakes

• The 1933 November 20 (M_s= 7.3) Baffin Bay earthquake