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Archive for November 10th, 2009

Bridges Spanning Bays by San Francisco, USA

37.7N 122.4W

November 10th, 2009 Category: Snapshots

California, USA - October 22nd, 2009

California, USA - October 22nd, 2009

The city of San Francisco, California, can be seen along the shores of the San Francisco Bay in this orthorectified image. A series of bodies of water are visible, as the San Francisco Bay (bottom right quadrant) is connected to the San Pablo Bay to the northwest, which in turn is joined with the Suisun Bay, above the image center.

The bridges spanning these bays appear as thin white or light grey lines in this ASAR image. These are, moving from the center to the lower right corner, the Richmond-San Rafael Bridge, the San Francisco-Oakland Bay Bridge, the San Mateo-Hayward Bridge, and the Dumbarton Bridge.

Ida Weakens to Tropical Storm and Turns Northward, Poised to Make Landfall on Gulf Coast

November 10th, 2009 Category: Tropical Cyclones

Tropical Storm Ida - November 9th, 2009

Tropical Storm Ida - November 9th, 2009

Track of Ida - November 9th, 2009 © Univ. of Wisconsin

Track of Ida

Enhanced image

Enhanced image

As of 3:00 PM CST (2100 UTC), the center of Tropical Storm Ida was located near latitude 28.4 north, longitude 88.5 west, or about 60 miles (95 km) southeast of the mouth of the Mississippi River and about 165 miles (265 km) south-southwest of Pensacola, Florida.

Ida is moving toward the north near 18 mph (30 km/hr). A reduction in forward speed is expected over Monday night. On the forecast track, the center of Ida should reach the northern gulf coast Monday night. After landfall, Ida is expected to turn eastward on Tuesday.

Maximum sustained winds are near 70 mph (110 km/hr) with higher gusts. Weakening is expected Monday evening as Ida moves over cooler waters prior to making landfall and is expected to merge with a frontal zone on Wednesday.

Tropical storm force winds extend outward up to 200 miles (325 km) from the center. The latest minimum central pressure reported was 991 mb (29.26 inches).

A tropical storm warning remains in effect from Grand Isle, Louisiana eastward to the Aucilla River, Florida, including New Orleans and Lake Pontchartrain, meaning that tropical storm conditions are expected somewhere within the warning area within 24 hours.

Rains from Ida are already moving across the coast within the warning area. Total storm accumulations of 3 to 6 inches, with isolated maximum storm totals of 8 inches, are possible through Wednesday evening from the central and eastern Gulf coast across the southeastern United States into the southern mid-atlantic states.

A dangerous storm tide will raise water levels by as much as 3 to 5 feet above ground level along the coast near and to the east of where the center makes landfall, as well as in areas of onshore flow in southeastern Louisiana. Near the coast, the surge will be accompanied by large and destructive waves.

Lakes in New Zealand’s Mackenzie Basin – November 10th, 2009

44.1S 170.1E

November 10th, 2009 Category: Image of the day, Lakes, Rivers

New Zealand - October 22nd, 2009

New Zealand - October 22nd, 2009

The bright blue waters of several lakes stand out against the snowy white peaks of the Southern Alps on New Zealand’s South Island. These lakes are in the Mackenzie Basin, an elliptical intermontane basin, located in the Mackenzie and Waitaki Districts.

The largest such basin in the country, it extends approximately 100 kilometers (62 miles) north to south, and 40 kilometers (25 miles) east to west. The Southern Alps constitute its western edge. Aside from a few mountain passes, the terrain is generally highest at the northern end and gradually descends in a southward direction.

Prominent rivers crossing the Mackenzie Basin include the Waitaki, the Ahuriri, the Hakataramea and the Tekapo Rivers. Lakes Ohau, Pukaki, Alexandrina and Tekapo lie within the Mackenzie Basin, as do the artificial hydroelectric lakes of Ruataniwha, Benmore and Aviemore.

Here, moving diagonally downward from the  upper right is the bright turquoise Lake Tekapo, followed by Lake Pukaki and finally by the slightly darker turquoise Lake Ohau. South of these three is the artificial Lake Benmore. Outside the basin, the dark blue Lakes Hawea (right) and Wanaka (left) are visible near the left edge of the image.

The Ust-Ilimsk Reservoir on the Angara River, Russia

58.0N 102.8E

November 10th, 2009 Category: Lakes, Rivers

Russia - October 5th, 2009

Russia - October 5th, 2009

The Angara River (Russian: Ангара́) is a 1,779 kilometers (1,105 mi) long river in Irkutsk Oblast and Krasnoyarsk Krai, south-east Siberia, Russia. It is the only river flowing out of Lake Baikal, and is a headwater of the Yenisei River.

Here, it is visible near Ust-Ilimsk, after flowing past Bratsk. It then turns west, enters the Krasnoyarsk Krai, and falls into the Yenisei near Strelka.

The Angara is dammed by the dams of three major hydroelectric plants that have been constructed since the 1950s: Irkutsk Dam, Bratsk Dam forming the Bratsk Reservoir, Ust-Ilimsk Dam forming the Ust-Ilimsk Reservoir (visible here), and Boguchany Dam (under construction) at Kodinsk.