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Climate Change in the Barents Sea – June 21st, 2013

70.2N 50.8E

June 21st, 2013 Category: Climate Change, Image of the day VIIRSSuomi-NPP

Russia – June 21st, 2013

Visible on the right side of this image is the Novaya Zemlya archipelago, part of Russia, between the Barents and Kara Seas. Recent data over the last decade show an Arctic wide temperature increase consistent with model projections of global warming rather than showing regional warming patterns which would have been caused by natural variability as occurred in previous Arctic warming episodes such as the 1930s.

While a major surprise was the nearly 40% loss of September sea ice extent in 2007, the major change is that in every year since then sea ice has been below 30% and that much old, thick sea ice has disappeared. Extensive forest fires are another major Arctic change. These shifts seem to be rapid and occurring 20-30 years earlier than expected by steady processes in climate forecast models.

The Arctic is normally dominated a very stable “Polar Vortex” of counter-clockwise circulating winds surrounding the North Pole which traps the cold Arctic air mass at high latitudes. However, during early winter of 2009-2010 the Polar Vortex weakened due to higher geopotential heights over the Arctic, allowing cold air to spill southwards and be replaced by warm air moving poleward, a warm Arctic –cold continent climate pattern. One
indicator of a weak Polar Vortex is the North Atlantic Oscillation (NAO) index which in December 2009 through February 2010 had its most negative value (weak vortex) in 145 years of record.

Meteorological attribution to these sub-Arctic events is difficult. Certainly random chaos in the development of weather patterns can produce such extreme events. There is a potential impact, however, from Arctic regions where heat stored in the ocean in sea-ice-free and thin ice areas has been released to the lower atmosphere during autumn. One would not expect a sub-Arctic impact in every year or the in the same locations every year. The Barents Sea seems to be part of the Arctic wide warming pattern, while northern Europe is in the subArctic high climate variability zone (click here for more information).

Fires in Guatemala and Southern Mexico – May 21st, 2013

17.3N 91W

May 21st, 2013 Category: Fires, Image of the day

Mexico – May 21st, 2013

The locations of fires burning in southern Mexico, mostly on the Isthmus of Tehuantepec, and in northern Guatemala are marked by red indicators in this image. Smoke from the fires blows over both countries and spreads northwestward across the Gulf of Mexico.

Climate Change and the Danish Coastline – April 21st, 2013

56.0N 10.0E

April 21st, 2013 Category: Climate Change, Image of the day

Denmark- April 20th, 2013

The Danish coastline measures 4605 km, bordering the Baltic Sea in the east and the North Sea in the west. Along the western coast, the country consists of a large peninsula, Jutland. Denmark is known for its many islands as Zealand and Lolland as well as its hundreds of minor islands often referred to as the Danish Archipelago.

The main climate change risks for the coastal zones of Denmark are likely to come from increased rainfall and flash storms. Also, the loss of eco-systems or wetlands due to climate change deserves attention.

The main populated areas of Denmark vulnerable to coastal flooding and erosion are the municipalities of Lolland and Greve situated along the Baltic Sea as well as the west coast of Jutland which is exposed to the North Sea.

Salt marshes and dunes are commonly found along the Danish coastline, especially along the west coast of Jutland. The areas constitute important natural habitats for a large number of plant and animal species (click here for more information).

Tropical Cyclone Imelda (21S) Restrengthens, Continues Towards Madagascar – April 14th, 2013

10.7S 53.4E

April 14th, 2013 Category: Image of the day, Tropical Cyclones

Tropical Storm Twenty One (21S) – April 13th, 2013

Enhanced image

Track of Tropical Storm Twenty One (21S) - April 12th, 2013 © Univ. of Wisconsin

Track of TC 21S

Tropical Cyclone Imelda (TC 21S), located approximately 315 nm northeast of La Reunion, has tracked west-southwestward at 03 knots over the past six hours.

Animated infrared satellite imagery shows a deepened central dense overcast feature over a well-defined low-level circulation center. This is also evident on an SSMI-S microwave pass. The initial position is based on closely grouped agency fixes and on the above microwave image with high confidence. The initial intensity is an average of subjective Dvorak estimates from PGTW, KNES, and FIMP.

Upper level analysis (ULA) indicates the system is between two ridge axes – one to the north and another to south in an area of low (05-10 knot) vertical wind shear (VWS). TC 21S has unpredictably tracked west-southwestward over the past 12 hours. From the same ULA, the steering ridge to the east was not significantly weakened by a passing mid-latitude trough as previously forecast. Instead, the ridge was deformed into a kidney-shaped anticyclone along a meridional axis. In response to this transformation to the steering ridge, 21S jogged westward. This recent development necessitated a slight change in the JTWC track forecast philosophy.

Tropical Cyclone Imelda (21S) May Re-intensify – April 12th, 2013

11.8S 54.8E

April 12th, 2013 Category: Image of the day, Tropical Cyclones

Tropical Storm Twenty One (21S) – April 11th, 2013

Enhanced image

Track of Tropical Storm Twenty One (21S) - April 11th, 2013 © Univ. of Wisconsin

Track of TC 21S

Tropical Cyclone Imelda (TC 21S) is forecast to continue tracking generally southward through TAU 48 as the steering ridge becomes re- established.

Beyond TAU 48 the system will shift to a southeastward track as it rounds the southern periphery of the steering ridge. Model guidance is in fair agreement with the forecast track, with NVGM being the western-most outlier and EGRR the eastern-most. There is also fair agreement with this scenario in the available ensemble model products.

Despite the slight weakening trend over the past 12 hours, favorable (28 to 29 degrees Celsius) sea surface temperatures, low to moderate vertical wind shear (VWS), and enhanced outflow from the deep-layer trough (DLT) should allow for a period of slight re-intensification through TAU 48. After that time, increasing interaction with mid-latitude westerlies will result in higher VWS, beginning a gradual dissipation of TC 21S.

Although there is some variability in the track speeds among dynamical models, they suggest that TC 21S will begin to interact with the baroclinic mid-latitude flow around TAU 120. Based on the fair agreement in model guidance there is high confidence in the forecast track. Maximum significant wave height is 30 feet.